Hot water supply system and hot water supply method

Abstract

A hot water supply system (100) includes: an obtainer (120) that obtains a plurality of items of hot water supply information, each including a boiling amount of a water heater (11) and a usage start time of the water heater (11), and a first reference power of a plurality of residences in which a plurality of water heaters (11) are respectively installed, each of the plurality of water heaters (11) being the water heater (11); a determiner (130) that, based on the boiling amount included in each of the plurality of items of the hot water supply information obtained, determines a schedule for starting boiling in order from a water heater (11), among the plurality of water heaters (11), for which a latest boiling start time is earliest, when starting boiling by the plurality of water heaters (11) simultaneously is determined to cause an overall demand power of the plurality of residences to exceed the first reference power obtained, the latest boiling start time being a latest time to start boiling to ensure hot water does not run out at the usage start time included in the hot water supply information for that water heater (11); and a controller (140) that controls boiling by the plurality of water heaters (11) based on the schedule determined.

Description

[Technical Field]

[0001] The present invention relates to a hot water supply system and a hot water supply method.[Background Art]

[0002] Patent Literature (PTL) 1 discloses a storage-type water heater. Such a storage-type water heater generally stores hot water boiled during a time slot when the power unit price is low in a storage tank, and then supplies that hot water as necessary. The power unit price is low in nighttime time slots, for example.[Citation List][Patent Literature]

[0003] [PTL 1] Japanese Unexamined Patent Application Publication No. 2012-225601[Summary of Invention][Technical Problem]

[0004] A plurality of the water heaters disclosed in PTL 1 may be installed in a housing complex including a plurality of residences, for example. In such a case, if the water heaters start boiling simultaneously during a nighttime time slot, the overall demand power of the housing complex at that time may become extremely high.

[0005] Incidentally, the types of contracts for supplying power to a housing complex include a high-voltage collective power reception contract. In such a contract, the management company or management association of the housing complex enters into a contract with the power company, and a user in each household then enters into a contract with the manager or management association of the housing complex. In a high-voltage collective power reception contract, a reference power, which is a reference value (an upper limit value) for the overall demand power of the housing complex, is set. If the reference power is exceeded, a contract in which the reference power is increased and the base rate is raised will be required for the current month and the 11 months from the following month.

[0006] Accordingly, if the overall demand power of a housing complex including a plurality of residences becomes extremely high due to boiling by a plurality of water heaters as described above, the demand power (and more specifically, a maximum value of the demand power) may exceed the reference power and cause the base rate to rise as a result. Problems such as breakers tripping also occur when the demand power increases.

[0007] The present invention provides a hot water supply system and the like capable of suppressing the maximum value of the overall demand power of a plurality of residences.[Solution to Problem]

[0008] A hot water supply system according to one aspect of the present invention includes: an obtainer that obtains a plurality of items of hot water supply information, each including a boiling amount of a water heater and a usage start time of the water heater, and a first reference power of a plurality of residences in which a plurality of water heaters are respectively installed, each of the plurality of water heaters being the water heater; a determiner that, based on the boiling amount included in each of the plurality of items of the hot water supply information obtained, determines a schedule for starting boiling in order from a water heater, among the plurality of water heaters, for which a latest boiling start time is earliest, when starting boiling by the plurality of water heaters simultaneously is determined to cause an overall demand power of the plurality of residences to exceed the first reference power obtained, the latest boiling start time being a latest time to start boiling to ensure hot water does not run out at the usage start time included in the hot water supply information for that water heater; and a controller that controls boiling by the plurality of water heaters based on the schedule determined.

[0009] A hot water supply method according to one aspect of the present invention is a hot water supply method executed by a hot water supply system, the hot water supply method including: obtaining a plurality of items of hot water supply information, each including a boiling amount of a water heater and a usage start time of the water heater, and a first reference power of a plurality of residences in which a plurality of water heaters are respectively installed, each of the plurality of water heaters being the water heater; determining, based on the boiling amount included in each of the plurality of items of the hot water supply information obtained, a schedule for starting boiling in order from a water heater, among the plurality of water heaters, for which a latest boiling start time is earliest, when starting boiling by the plurality of water heaters simultaneously is determined to cause an overall demand power of the plurality of residences to exceed the first reference power obtained, the latest boiling start time being a latest time to start boiling to ensure hot water does not run out at the usage start time included in the hot water supply information for that water heater; and controlling boiling by the plurality of water heaters based on the schedule determined.[Advantageous Effects of Invention]

[0010] The hot water supply system and the like of the present invention make it possible to suppress the maximum value of the overall demand power of a plurality of residences.[Brief Description of Drawings]

[0011] [FIG. 1A] FIG. 1A is a block diagram illustrating the functional configuration of a hot water supply system according to an embodiment. [FIG. 1B] FIG. 1B is a diagram illustrating an example of a power unit price according to the embodiment. [FIG. 2] FIG. 2 is a flowchart of Operation Example 1 according to the embodiment. [FIG. 3] FIG. 3 is a diagram illustrating a schedule of Operation Example 1 according to the embodiment. [FIG. 4] FIG. 4 is a more detailed flowchart illustrating step S30 of Operation Example 1 according to the embodiment. [FIG. 5] FIG. 5 is another diagram illustrating a schedule of Operation Example 1 according to the embodiment. [FIG. 6] FIG. 6 is a flowchart of Operation Example 2 according to the embodiment. [FIG. 7] FIG. 7 is a diagram illustrating a schedule of Operation Example 2 according to the embodiment. [FIG. 8] FIG. 8 is a flowchart of Operation Example 3 according to the embodiment. [FIG. 9] FIG. 9 is a diagram illustrating a schedule of Operation Example 3 according to the embodiment. [FIG. 10] FIG. 10 is a flowchart of Operation Example 4 according to the embodiment. [FIG. 11] FIG. 11 is a diagram illustrating a schedule of Operation Example 4 according to the embodiment. [FIG. 12] FIG. 12 is a flowchart of Operation Example 5 according to the embodiment. [FIG. 13] FIG. 13 is a diagram illustrating a schedule of Operation Example 5 according to the embodiment. [FIG. 14] FIG. 14 is a flowchart of Operation Example 6 according to the embodiment. [FIG. 15] FIG. 15 is a diagram illustrating a schedule of Operation Example 6 according to the embodiment. [FIG. 16] FIG. 16 is a flowchart of Operation Example 7 according to the embodiment. [FIG. 17] FIG. 17 is a flowchart of Operation Example 8 according to the embodiment. [FIG. 18] FIG. 18 is a diagram illustrating a schedule and an electricity rate of Operation Example 8 according to the embodiment. [FIG. 19] FIG. 19 is a flowchart of Operation Example 9 according to the embodiment. [FIG. 20] FIG. 20 is a diagram illustrating a schedule of Operation Example 9 according to the embodiment. [FIG. 21] FIG. 21 is a flowchart of Operation Example 10 according to the embodiment. [FIG. 22] FIG. 22 is a flowchart of Operation Example 11 according to the embodiment. [FIG. 23] FIG. 23 is a flowchart of Operation Example 12 according to the embodiment. [FIG. 24] FIG. 24 is a block diagram illustrating the functional configuration of a hot water supply system according to Variation 1 on the embodiment. [FIG. 25] FIG. 25 is a block diagram illustrating the functional configuration of a hot water supply system according to Variation 2 on the embodiment. [FIG. 26] FIG. 26 is a block diagram illustrating the functional configuration of a hot water supply system according to Variation 3 on the embodiment. [Description of Embodiment]

[0012] An embodiment will be described in detail hereinafter with reference to the drawings. The following embodiment will describe general or specific examples. The numerical values, shapes, materials, constituent elements, arrangements and connection states of constituent elements, steps, orders of steps, and the like in the following embodiment are merely examples, and are not intended to limit the present invention. Additionally, of the constituent elements in the following embodiment, constituent elements not denoted in the independent claims will be described as optional constituent elements.

[0013] Note also that the drawings are schematic diagrams, and are not necessarily exact illustrations. Configurations that are substantially the same are given the same reference signs in the drawings, and redundant descriptions may be omitted or simplified.[Embodiment][Configuration]

[0014] The configuration of hot water supply system 100 according to the present embodiment will be described.

[0015] FIG. 1A is a block diagram illustrating the functional configuration of hot water supply system 100 according to the present embodiment.

[0016] Hot water supply system 100 is a system installed in housing complex 40. Accordingly, FIG. 1A is a block diagram also illustrating functional configurations of housing complex 40 aside from hot water supply system 100. Hot water supply system 100 suppresses a maximum value of the overall demand power of housing complex 40 by controlling a plurality of water heaters 11 installed in a plurality of residences included in housing complex 40.

[0017] In housing complex 40 according to the present embodiment, a high-voltage collective power reception contract is selected as the type of contract for supplying power to housing complex 40. In this contract, two types of time slots having different power unit prices are provided, the two types of time slots being, for example, a first time slot and a second time slot in which the power unit price is lower than in the first time slot. Note, however, that in the contract, three types of time slots having different power unit prices may be provided, the three types of time slots being, for example, a first time slot, a second time slot in which the power unit price is lower than in the first time slot, and a third time slot in which the power unit price is higher than in the first time slot. In the contract, four or more types of time slots having different power unit prices may be provided.

[0018] The power unit price and time slots will be described further with reference to FIG. 1B.

[0019] FIG. 1B is a diagram illustrating an example of the power unit price according to the present embodiment. More specifically, (a) of FIG. 1B is a diagram illustrating an example in which two types of time slots having different power unit prices are provided for a single day, and (b) of FIG. 1B is a diagram illustrating an example in which the power unit price changes each predetermined time period (e.g., 30 minutes) in a single day. In the present embodiment, as described above, two types of time slots may be provided, three or more types of time slots may be provided, and the power unit price may fluctuate every predetermined time period (e.g., 30 minutes) as indicated in (b) of FIG. 1B. Hereinafter, unless otherwise stated, the present embodiment will be described assuming that two types of time slots having different power unit prices are provided.

[0020] For example, the first time slot is a time slot other than at night, and the second time slot is a time slot at night. Unless otherwise stated, the first time slot in which the power unit price is higher is from 7 AM to 11 PM, the second time slot in which the power unit price is lower is from 11 PM to 7 AM the next day, and the first time slot and the second time slot are consecutive time slots. In general, hot water stored in water heater 11 has a higher usage amount and usage frequency in the first time slot other than at night, and a low usage amount and usage frequency in the second time slot at night.

[0021] Hot water supply system 100 according to the present embodiment determines a schedule for boiling by the plurality of water heaters 11 before boiling by the plurality of water heaters 11 starts, and controls the plurality of water heaters 11 based on the schedule determined. For example, hot water supply system 100 determines a schedule for boiling by the plurality of water heaters 11 before the start of the second time slot, i.e., during the first time slot, and controls the plurality of water heaters 11 based on the schedule determined.

[0022] Housing complex 40 is a facility including a plurality of households (i.e., a plurality of residences) and common area 20, and is, for example, an apartment building or the like.

[0023] The number of households in housing complex 40 is, for example, in the teens, 20 to 100, or hundreds, but is not limited thereto. Here, each of the plurality of households is individual dwelling 10 (i.e., a residence) of a resident, and may be referred to as first individual dwelling 10a, second individual dwelling 10b, third individual dwelling 10c, fourth individual dwelling 10d, and fifth individual dwelling 10e for identification. The plurality of households also include a plurality of other individual dwellings 10 in addition to first to fifth individual dwellings 10a to 10e. When there is no particular need for identification, first to fifth individual dwellings 10a to 10e may simply be referred to as individual dwellings 10.

[0024] Each of the plurality of households includes water heater 11, electrical equipment 12, and control device 13. In other words, each of the plurality of water heaters 11 installed in a plurality of residences is a water heater provided for a corresponding one of the plurality of households, and more specifically, is a storage-type water heater. For identification, water heaters 11 provided in first to fifth individual dwellings 10a to 10e will be referred to as first to fifth water heaters 11a to 11e. In other words, the plurality of water heaters 11 include first to fifth water heaters 11a to 11e. When there is no particular need for identification, first to fifth water heaters 11a to 11e may simply be referred to as "water heaters 11". Each of the plurality of water heaters 11 communicates with a respective one of a plurality of control devices 13.

[0025] Electrical equipment 12 and control device 13 have the same functions throughout the plurality of households, and thus electrical equipment 12 and control device 13 provided in first individual dwelling 10a will be described here as an example.

[0026] "Electrical equipment 12" refers to all electrical equipment in first individual dwelling 10a aside from first water heater 11a. For example, electrical equipment 12 includes household appliances such as lighting fixtures, air conditioners, and the like in first individual dwelling 10a.

[0027] Control device 13 is a device for communicating with and controlling first water heater 11a and electrical equipment 12 in first individual dwelling 10a. More specifically, control device 13 is what is known as a Home Energy Management System (HEMS) controller that monitors or controls the operating states of first water heater 11a and electrical equipment 12 by communicating with first water heater 11a and electrical equipment 12. For example, through this communication, control device 13 obtains, from first water heater 11a, the remaining hot water amount in a storage tank of first water heater 11a (also called a "stored hot water amount"). Control device 13 also communicates with hot water supply system 100.

[0028] Control device 13 includes an acceptor that accepts operations from an owner (i.e., a resident) of first individual dwelling 10a. Specifically, the acceptor is realized by a touch panel or the like. This acceptor accepts, from the owner of first individual dwelling 10a, an operation instructing a target boiling amount for first water heater 11a, for example.

[0029] The target boiling amount is a target amount for the remaining hot water amount in the storage tank (stored hot water amount) of first water heater 11a when boiling by first water heater 11a is completed by hot water supply system 100. The target boiling amount may also be a hot water amount expected to be used by the owner of first individual dwelling 10a. It should be noted that control device 13 may determine a value obtained by subtracting (i) the remaining hot water amount in the storage tank of first water heater 11a (more specifically, the stored hot water amount from before the boiling) obtained from (ii) the target boiling amount indicated by the accepted instruction as the boiling amount of first water heater 11a.

[0030] The acceptor of control device 13 accepts, from the owner of first individual dwelling 10a, an operation instructing a usage start time, which is a time at which the use of hot water stored in first water heater 11a starts.

[0031] Control device 13 outputs hot water supply information about first water heater 11a to hot water supply system 100. The hot water supply information for first water heater 11a is information including a determined boiling amount (i.e., the boiling amount of first water heater 11a) and a usage start time indicated by an instruction accepted by the acceptor of control device 13 (i.e., a usage start time of first water heater 11a).

[0032] In addition, control device 13 outputs, to hot water supply system 100, individual dwelling power information about the power used by electrical equipment 12.

[0033] The individual dwelling power information includes information indicating an expected used power based on an expected usage amount for electrical equipment 12. The information indicating the expected used power is information based on an expected usage amount for electrical equipment 12, the expected usage amount being for a predetermined time slot (e.g., the second time slot) on a given day. For example, at 10 PM, which corresponds to the first time slot on that day, control device 13 predicts and determines the expected used power for the second time slot starting at 11 PM on that day, based on the past used power amount for electrical equipment 12 on that day. In this case, as the expected used power for electrical equipment 12 for that day, control device 13 determines an average value of the power used by electrical equipment 12 in the second time slot over a past predetermined period (e.g., a period of one week in the past from the previous day). The individual dwelling power information also includes information indicating the power used by electrical equipment 12 at the present time in a predetermined time slot (e.g., the second time slot) on a given day. Control device 13 outputs such individual dwelling power information to hot water supply system 100. Note that the predetermined time slot on a given day described above is not limited to the second time slot, and may be the first time slot.

[0034] Common area 20 in housing complex 40 is, for example, an area other than the plurality of households (residences) in housing complex 40, and is a common space such as hallways, the roof, gardens, staircases, and the like, for example.

[0035] Electrical equipment 21 and power measurement device 22 are installed in common area 20. Lighting, elevators, water pumps, and the like, for example, fall under electrical equipment 21. Power measurement device 22 measures the power used by electrical equipment 21 and outputs the measured power used to hot water supply system 100.

[0036] Furthermore, power measurement device 22 outputs, to hot water supply system 100, common area power information about the power used by electrical equipment 21. The common area power information includes information indicating an expected used power based on an expected usage amount for electrical equipment 21. The information indicating the expected used power is information based on an expected usage amount for electrical equipment 21, the expected usage amount being for a predetermined time slot (e.g., the second time slot) on a given day. For example, at 10 PM, which corresponds to the first time slot on that day, power measurement device 22 predicts and determines the expected used power for the second time slot starting at 11 PM on that day, based on the past used power amount for electrical equipment 21 on that day. In this case, as the expected used power for electrical equipment 21 for that day, power measurement device 22 determines an average value of the power used by electrical equipment 21 in the second time slot over a past predetermined period (e.g., a period of one week in the past from the previous day). The common area power information also includes information indicating the power used by electrical equipment 21 at the present time in a predetermined time slot (e.g., the second time slot) on a given day. Control device 13 outputs such common area power information to hot water supply system 100. Note that the predetermined time slot on a given day described above is not limited to the second time slot, and may be the first time slot.

[0037] Power supply equipment 23 is also installed in common area 20. Solar power generation equipment, charging equipment, and the like, for example, fall under power supply equipment 23. In other words, in the present embodiment, housing complex 40 includes power supply equipment 23, and power supply equipment 23 includes solar power generation equipment and charging equipment (e.g., storage batteries and electric automobiles).

[0038] The power output from power supply equipment 23 is supplied to a plurality of households (the plurality of water heaters 11, for example).

[0039] Note that power supply equipment 23 outputs power supply equipment information indicating a power generation amount, a charging amount, and the like by power supply equipment 23 to power measurement device 22, and power measurement device 22 outputs the obtained power supply equipment information to hot water supply system 100.

[0040] The constituent elements of hot water supply system 100 will be described here.

[0041] As illustrated in FIG. 1A, hot water supply system 100 includes communicator 110, obtainer 120, determiner 130, controller 140, and storage 150. Hot water supply system 100 is, for example, a personal computer, but may also be a server device or the like.

[0042] Communicator 110 is communication circuitry for hot water supply system 100 to communicate with control device 13 provided in each of the plurality of households and power measurement device 22 of common area 20. In the present embodiment, communicator 110 is circuitry for wireless communication, and communicator 110 communicates wirelessly according to various communication standards. Note that communicator 110 may be circuitry for communicating over wires.

[0043] Communicator 110 obtains the hot water supply information for each of the plurality of water heaters 11 from control device 13 of corresponding ones of the plurality of households. In other words, for example, communicator 110 obtains hot water supply information of first water heater 11a from control device 13 of first individual dwelling 10a, and obtains hot water supply information of second water heater 11b from control device 13 of second individual dwelling 10b.

[0044] Obtainer 120 is a processor that obtains a plurality of items of the hot water supply information and a first reference power. More specifically, obtainer 120 obtains the hot water supply information for each of the plurality of water heaters 11 obtained by communicator 110, and obtains the first reference power stored in storage 150. Note that this first reference power is a reference power for a plurality of residences in which a plurality of water heaters 11 are installed (here, housing complex 40), and is, for example, a reference power for the second time slot. The first reference power for the second time slot is a reference power specified in a high-voltage collective power reception contract, and is a first reference power for housing complex 40 in which the plurality of water heaters 11 are installed. When the overall demand power of housing complex 40 exceeds the first reference power, a contract in which the first reference power has been raised and the base rate is higher is required for the current month and the 11 months from the following month.

[0045] Determiner 130 determines a schedule based on the plurality of items of hot water supply information obtained by obtainer 120 and the first reference power obtained by obtainer 120. The schedule indicates a planned start time and a planned end time for the boiling by each of the plurality of water heaters 11. The schedule is, for example, a schedule for the boiling by each of the plurality of water heaters 11 in the second time slot. However, the schedule is not limited thereto, and may be, for example, a schedule for the boiling by each of the plurality of water heaters 11 in the first, second, and third time slots. The schedule further indicates a supply source that supplies power required for the boiling by each of the plurality of water heaters 11. Examples of the supply source include a power company, power supply equipment 23, and the like.

[0046] Controller 140 is a processor that controls the boiling by the plurality of water heaters 11 based on the schedule determined by determiner 130. Here, controller 140 causes communicator 110 to output, to each of the plurality of control devices 13, a control signal instructing the plurality of water heaters 11 to boil as indicated by the determined schedule.

[0047] As a result, each of the plurality of control devices 13 controls the corresponding one of the plurality of water heaters 11 according to the control signal output from communicator 110.

[0048] Each of obtainer 120, determiner 130, and controller 140 is realized by a microcomputer, for example, but may be realized by a processor or dedicated circuitry. The respective functions of obtainer 120, determiner 130, and controller 140 are realized by hardware such as microcomputers constituting obtainer 120, determiner 130, and controller 140, respectively, executing software stored in storage 150.

[0049] Storage 150 is a storage device that stores information necessary for information processing for controlling the plurality of water heaters 11, such as software executed by obtainer 120, determiner 130, and controller 140. Storage 150 is realized by semiconductor memory or the like, for example.

[0050] Operations performed in hot water supply system 100 according to the present embodiment having the foregoing configuration will be described next.[Operation Example 1]

[0051] FIG. 2 is a flowchart of Operation Example 1 according to the present embodiment.

[0052] As illustrated in FIG. 2, steps S10, S20, S30, and S40 are processing performed in the first time slot, and step S90 is processing performed in the second time slot. Note that the time slot in which a step is performed may be indicated in the flowcharts in subsequent figures as well.

[0053] Although the present operation example describes an example in which the schedule is determined in the first time slot and the boiling by the plurality of water heaters 11 is performed in the second time slot, the configuration is not limited thereto. As described above, hot water supply system 100 may determine a schedule for boiling by the plurality of water heaters 11 before the boiling by the plurality of water heaters 11 starts, and control the boiling by the plurality of water heaters 11 based on the schedule determined. Accordingly, for example, the schedule may be determined in the second time slot, and the boiling by the plurality of water heaters 11 may be performed in the first time slot. In the example illustrated in (b) of FIG. 1B, for example, the schedule may be determined by the start of a predetermined time slot (e.g., 12 PM to 2 PM), and the boiling by the plurality of water heaters 11 may be performed in the predetermined time slot.

[0054] First, obtainer 120 obtains a plurality of items of hot water supply information, each including a boiling amount and a usage start time, and a first reference power (S10). Here, obtainer 120 obtains the first reference power for the second time slot. Obtainer 120 obtains the plurality of items of hot water supply information obtained by communicator 110, and obtains the first reference power stored in storage 150. Before this step S10 is performed, each of the plurality of control devices 13 outputs the hot water supply information about the corresponding water heater 11 to hot water supply system 100 as described above.

[0055] In step S10, obtainer 120 may obtain the target boiling amount and the remaining hot water amount in the storage tank for each of the plurality of water heaters 11, obtained by communicator 110.

[0056] Note that step S10 corresponds to a step of obtaining.

[0057] In Operation Example 1, in the process of step S10, obtainer 120 obtains the individual dwelling power information about the power used by electrical equipment 12, and the common area power information about the power used by electrical equipment 21. More specifically, communicator 110 obtains the individual dwelling power information from each of the plurality of control devices 13 and the common area power information from power measurement device 22, and obtainer 120 obtains the individual dwelling power information and the common area power information obtained by communicator 110.

[0058] Accordingly, obtainer 120 obtains information indicating the expected used power based on the expected usage amount, in the second time slot, for electrical equipment 12 included in the individual dwelling power information. Likewise, obtainer 120 obtains information indicating the expected used power based on the expected usage amount, in the second time slot, for electrical equipment 21 included in the common area power information. In the present embodiment, all of the plurality of electrical equipment 12 in the plurality of households and electrical equipment 21 in common area 20 constitute electrical equipment aside from the plurality of water heaters 11 in housing complex 40. Accordingly, it can also be said that obtainer 120 obtains a second used power based on the expected usage amount, in the second time slot, by the electrical equipment aside from the plurality of water heaters 11 in housing complex 40.

[0059] Note that the "second used power" is information that integrates the expected used power, in the second time slot, for electrical equipment 12 indicated by the individual dwelling power information, and the expected used power, in the second time slot, for electrical equipment 21 indicated by the common area power information.

[0060] In this manner, in Operation Example 1, in the process of step S10, obtainer 120 obtains the second used power, which corresponds to the expected power amount in the second time slot for the electrical equipment aside from the plurality of water heaters 11 in housing complex 40.

[0061] Based on the boiling amounts included in the plurality of items of hot water supply information obtained by obtainer 120, determiner 130 determines whether the overall demand power of housing complex 40 will exceed the first reference power obtained if the plurality of water heaters 11 start boiling simultaneously (S20). Here, determiner 130 determines whether the overall demand power of housing complex 40 will exceed the first reference power obtained if the plurality of water heaters 11 start boiling simultaneously in the second time slot. More specifically, determiner 130 makes this determination based on the boiling amounts included in the plurality of items of hot water supply information and the second used power obtained (an expected power amount in the second time slot).

[0062] Subsequently, if determiner 130 determines that the demand power will exceed the first reference power (Yes in S20), determiner 130 determines the following schedule prior to the second time slot, i.e., the first time slot, in this instance. Determiner 130 determines a schedule that starts boiling in order from water heater 11, among the plurality of water heaters 11, for which a latest boiling start time is earliest (S30). The "latest boiling start time" is the latest time to start boiling so that hot water will not run out at the usage start time included in the hot water supply information for that water heater 11. For example, in first water heater 11a, if the usage start time is 6 AM and the time required for boiling is 3 hours, the latest boiling start time of first water heater 11a is 3 AM. If, in this case, the boiling start time of first water heater 11a is determined to be 5:50 AM or the like, it is likely that the remaining hot water amount will be insufficient at 6 AM, which is the usage start time, and that the hot water will run out (no hot water will remain).

[0063] Step S20 and step S30 will be described in more detail with reference to FIG. 3.

[0064] FIG. 3 is a diagram illustrating a schedule of Operation Example 1 according to the present embodiment. More specifically, (a) of FIG. 3 is a diagram illustrating the schedule when the plurality of water heaters 11 (first to third water heaters 11a to 11c) start boiling simultaneously, and (b) of FIG. 3 is a diagram illustrating the schedule when the start of boiling by third water heater 11c is delayed.

[0065] In FIG. 3, the period from t0 to t1, which indicate times, corresponds to the second time slot, and the period from t1 on corresponds to the first time slot. In step S20, determiner 130 determines whether the demand power will exceed the first reference power if the plurality of water heaters 11 start boiling at t0, which is the time at which the second time slot starts. The "demand power" is the sum of all the power used by the plurality of water heaters 11, the plurality of electrical equipment 12, and electrical equipment 21 in housing complex 40. The power used (consumed power) for the boiling by water heater 11 is proportional to the boiling amount by that water heater 11. As the boiling amount decreases, the time required for boiling by water heater 11 decreases as well.

[0066] In the schedule illustrated in (a) of FIG. 3, the demand power is higher than the first reference power, and determiner 130 therefore determines that the demand power will exceed the first reference power.

[0067] In addition, in the schedule illustrated in FIG. 3, the latest boiling start time of first water heater 11a is t11, the latest boiling start time of second water heater 11b is t12, and the latest boiling start time of third water heater 11c is t13. t11 is a time earlier than t12 and t13, and t12 is a time earlier than t13.

[0068] In such a case, determiner 130 determines a schedule to expedite the start of boiling by first and second water heaters 11a and 11b, which have an earlier latest boiling start time than third water heater 11c among first to third water heaters 11a to 11c (the schedule indicated by (b) of FIG. 3). In other words, determiner 130 determines a schedule that delays the start of boiling by third water heater 11c for which the latest boiling start time is the latest among first to third water heaters 11a to 11c. At this time, determiner 130 determines the schedule such that the demand power does not exceed the first reference power in the second time slot.

[0069] In (b) of FIG. 3, the boiling by first and second water heaters 11a and 11b begins simultaneously at time t0, at which the second time slot begins. However, the configuration is not limited thereto. A case will be described in which the demand power will exceed the first reference power if the boiling by first and second water heaters 11a and 11b starts simultaneously. In this case, determiner 130 determines a schedule that expedites the start of boiling by first water heater 11a, which has an earlier latest boiling start time than second water heater 11b among first and second water heaters 11a and 11b.

[0070] In this manner, determiner 130 determines a schedule that starts boiling in order from water heater 11 for which the latest boiling start time is the earliest.

[0071] Note that step S20 and step S30 correspond to a step of determining.

[0072] However, if determiner 130 determines that the demand power will not exceed the first reference power (No in S20), determiner 130 determines the following schedule prior to the second time slot, i.e., the first time slot, in this instance. Determiner 130 determines a schedule that starts the boiling by the plurality of water heaters 11 simultaneously (step S40).

[0073] Furthermore, controller 140 controls the boiling by the plurality of water heaters 11 based on the schedule determined by determiner 130 in step S30 or S40 (S90). Here, controller 140 controls boiling by the plurality of water heaters 11 in the second time slot based on the schedule determined. More specifically, controller 140 controls communicator 110 to output, to each of the plurality of control devices 13, a control signal instructing the plurality of water heaters 11 to boil as indicated by the determined schedule. As a result, each of the plurality of control devices 13 controls a corresponding one of the plurality of water heaters 11 based on control signals obtained from communicator 110. For example, control device 13 of first individual dwelling 10a causes first water heater 11a to boil using time t0 indicated in (b) of FIG. 3 as a boiling start time of first water heater 11a. Additionally, for example, control device 13 of second individual dwelling 10b causes second water heater 11b to boil using time t0 indicated in (b) of FIG. 3 as the boiling start time of second water heater 11b. Additionally, for example, control device 13 of third individual dwelling 10c causes third water heater 11c to boil using time t13 indicated in (b) of FIG. 3 as the boiling start time of third water heater 11c. Note that step S90 corresponds to a step of controlling.

[0074] In this manner, if determiner 130 determines that the demand power will exceed the first reference power in the first time slot (Yes in S20), determiner 130 determines the following schedule. Determiner 130 determines a schedule that starts boiling in order from water heater 11 for which the latest boiling start time is the earliest among the plurality of water heaters 11.

[0075] Through this, in Operation Example 1, hot water supply system 100 capable of suppressing the overall demand power (and more specifically, the maximum value of the demand power) of housing complex 40 is realized. For example, as indicated in (b) of FIG. 3, situations where the maximum value of the demand power exceeds the first reference power are suppressed. This makes it less likely that the base rate for housing complex 40 will rise.

[0076] The time range over which the boiling start time can be changed is shorter for water heater 11 having an earlier latest boiling start time than for water heater 11 having a later latest boiling start time. For example, as illustrated in FIG. 3, if the boiling by second water heater 11b does not start between time t0 and time t12, the hot water from second water heater 11b will run out. On the other hand, the boiling by third water heater 11c may start between time t0 and time t13, and the hot water from third water heater 11c will not run out even if the boiling starts between time t12 and time t13, unlike second water heater 11b.

[0077] In this manner, determiner 130 determining a schedule in which boiling by water heater 11 having a shorter time range over which the boiling start time can be changed (here, second water heater 11b) is prioritized makes it less likely that the hot water from second water heater 11b will run out.

[0078] More detailed processing in step S30 will now be described with reference to FIGS. 4 and 5.

[0079] FIG. 4 is a more detailed flowchart illustrating step S30 of Operation Example 1 according to the present embodiment. FIG. 5 is another diagram illustrating a schedule of Operation Example 1 according to the present embodiment. More specifically, (a) of FIG. 5 is a diagram illustrating the schedule when the plurality of water heaters 11 start boiling simultaneously, in the same manner as (a) of FIG. 3, and (b) of FIG. 5 illustrates the schedule when the start of boiling by second water heater 11b is delayed.

[0080] In FIGS. 4 and 5, the latest boiling start time of first water heater 11a is t11, the latest boiling start time of second water heater 11b is t12, and the latest boiling start time of third water heater 11c is t13. t11 is a time earlier than t12 and t13, and t12 and t13 are the same time.

[0081] As illustrated in FIG. 4, in step S30, determiner 130 determines a schedule that starts boiling in order from water heater 11 for which the latest boiling start time is the earliest among the plurality of water heaters 11.

[0082] More specifically, determiner 130 determines whether two water heaters 11 for which the latest boiling start time is the same time are present among the plurality of water heaters 11 (S30a).

[0083] If two water heaters 11 for which the latest boiling start time is the same time are present (Yes in step S30a), determiner 130 determines the following schedule. In this case, determiner 130 determines a schedule that starts boiling in order from water heater 11, among the two water heaters 11, having the highest boiling amount included in the hot water supply information for that water heater 11 (S30b).

[0084] Steps S30a and S30b will be described in more detail with reference to FIG. 5.

[0085] As described above, t11 is a time earlier than t12 and t13. Accordingly, first, determiner 130 determines a schedule that expedites the start of boiling by first water heater 11a for which, among first to third water heaters 11a to 11c, the latest boiling start time is earlier than second and third water heaters 11b and 11c.

[0086] t12 and t13 are the same time. Here, the boiling amount included in the hot water supply information for third water heater 11c is higher than the boiling amount included in the hot water supply information for second water heater 11b. Accordingly, determiner 130 determines a schedule that expedites the start of boiling by third water heater 11c, which has a higher boiling amount than second water heater 11b, among second and third water heaters 11b and 11c (the schedule indicated in (b) of FIG. 5).

[0087] The processing of step S90 is then performed.

[0088] Water heater 11 having a higher boiling amount requires a longer time for boiling. In Operation Example 1 illustrated in FIGS. 4 and 5, the schedule is determined such that boiling by water heater 11 having a high boiling amount in this manner (e.g., third water heater 11c) is performed preferentially, which makes it less likely that water heater 11 will run out of hot water. Having water heater 11 that has a high boiling amount perform boiling in a time slot when the power unit price is lower (the second time slot) provides a greater electricity rate reduction effect than having that water heater 11 perform boiling in the first time slot. Accordingly, determining the schedule such that water heater 11 having a higher boiling amount boils preferentially reduces the electricity rate paid by the owner of that water heater 11.

[0089] Operation Example 1 may also be configured as follows.

[0090] The boiling amounts of first to fifth water heaters 11a to 11e may be different from each other, and the usage start times of first to fifth water heaters 11a to 11e may be different from each other. In other words, each of the owners of first to fifth individual dwellings 10a to 10e can set a preferred numerical value by operating the acceptor of control device 13.

[0091] As described above, the hot water supply information for each of first to fifth water heaters 11a to 11e includes the boiling amount and the usage start time for that water heater 11. In the present embodiment, the hot water supply information for each of first to fifth water heaters 11a to 11e is determined by the owner operating the acceptor of control device 13, but the configuration is not limited thereto.

[0092] For example, the manager of hot water supply system 100 may obtain information about the boiling amounts and the usage start times by conducting a questionnaire on the use of hot water with the owners of first to fifth individual dwellings 10a to 10e. By controlling an information terminal such as a smartphone, a tablet, or a personal computer, the manager sends information about the boiling amounts and the usage start times to communicator 110 of hot water supply system 100. Obtainer 120 of hot water supply system 100 may obtain the information about the boiling amounts and the usage start times, and determine these as the boiling amounts and the usage start times for first to fifth water heaters 11a to 11e, respectively. The questionnaire also asks each owner about the types of hot water usage (bathing, showering, or other household chores), the hot water usage amount for each type, and the timing of each behavior, in each season, for first to fifth individual dwellings 10a to 10e.

[0093] Additionally, for example, the hot water supply information for first to fifth water heaters 11a to 11e may be determined based on past usage data, rather than a questionnaire as described above. It is desirable that the boiling amount and the usage start time in a past predetermined period for first water heater 11a, for example, be stored as the past usage data in storage 150 of hot water supply system 100. The past predetermined period is, for example, a period from the day before the one day back to one week prior thereto, but is not limited thereto. Obtainer 120 may obtain the hot water supply information based on the past usage data. For example, the boiling amount included in the hot water supply information based on the past usage data is an average value of the boiling amounts from the past predetermined period. Additionally, for example, the usage start time included in the hot water supply information based on the past usage data is an average value of the usage start times from the past predetermined period.

[0094] For example, the hot water supply information for first to fifth water heaters 11a to 11e may be determined based on life schedule information obtained from the information terminals of the owners of first to fifth individual dwellings 10a to 10e. If the owner is using a schedule management app on their smartphone, which is an example of an information terminal, control device 13 may obtain, from the information terminal, the life schedule information, which indicates a daily life schedule of the owner. The boiling amount and usage start time included in the hot water supply information may be determined based on the obtained life schedule information. In addition, by accepting an operation instructing a target boiling amount and an operation instructing a usage start time from the owner, the information terminal may output information instructing the target boiling amount and the usage start time to control device 13. The hot water supply information may be determined in this manner.[Operation Example 2]

[0095] FIG. 6 is a flowchart of Operation Example 2 according to the present embodiment. FIG. 7 is a diagram illustrating a schedule of Operation Example 2 according to the present embodiment.

[0096] Operation Example 2 will describe an example in which three types of time slots having different power unit prices (first to third time slots) are provided, and a schedule for boiling by one water heater 11 (here, first water heater 11a) is determined.

[0097] As illustrated in FIG. 6, the processing of step S10 is performed first, in the same manner as in FIG. 2.

[0098] Then, obtainer 120 obtains the first power unit price for the first time slot and the second power unit price for the second time slot. More specifically, obtainer 120 obtains the first power unit price for the first time slot, the second power unit price for the second time slot, and the third power unit price for the third time slot (S11). Obtainer 120 obtains the first power unit price, the second power unit price, and the third power unit price stored in storage 150, for example.

[0099] The power unit price is the electricity rate per kWh, and is a value that varies depending on the time slot. The first power unit price is Y yen / kWh, the second power unit price is X yen / kWh, and the third power unit price is Z yen / kWh. In addition, the second power unit price is cheaper than the first power unit price, and the first power unit price is cheaper than the third power unit price.

[0100] In Operation Example 2, the second time slot is from 11 PM to 7 AM the next day, the first time slot is from 7 AM to 12 PM, and the third time slot is from 12 PM to 11 PM. The second time slot, the first time slot, and the third time slot are consecutive time slots.

[0101] Determiner 130 determines a schedule based on the first power unit price and the second power unit price obtained by obtainer 120 to lower the electricity rate from the boiling by the plurality of water heaters 11. In the present operation example, the schedule is determined to lower the electricity rate from the boiling by first water heater 11a based on the first to third power unit prices obtained by obtainer 120 (S31).

[0102] Step S31 will be described in more detail with reference to FIG. 7.

[0103] As described above, the second power unit price is cheaper than the first power unit price and the first power unit price is cheaper than the third power unit price, and determiner 130 therefore determines a schedule such that the boiling by first water heater 11a is performed during the second time slot in which the power unit price is the lowest. Furthermore, as illustrated in FIG. 7, determiner 130 determines a schedule in which if the boiling by first water heater 11a is not completed during the second time slot, the remaining boiling is performed during the first time slot, in which the power unit price is the second lowest.

[0104] The processing of step S90 is then performed in the same manner as in FIG. 2.

[0105] In Operation Example 2, the boiling by water heater 11 (e.g., first water heater 11a) is performed during a time slot in which the power unit price is lower, which makes it possible to reduce the electricity rate paid by the owner of water heater 11.[Operation Example 3]

[0106] FIG. 8 is a flowchart of Operation Example 3 according to the present embodiment. FIG. 9 is a diagram illustrating a schedule of Operation Example 3 according to the present embodiment. (a) of FIG. 9 illustrates a schedule for boiling by first water heater 11a during a second time slot starting at an earlier time, and (b) of FIG. 9 illustrates a schedule for boiling by first water heater 11a during a second time slot starting at a later time.

[0107] Operation Example 3 will describe an example in which two types of time slots having different power unit prices (first and second time slots) are provided, and a schedule for boiling by one water heater 11 (here, first water heater 11a) is determined. In the present operation example, two of the second time slots are provided for one day, i.e., a plurality of the second time slots are provided. For identification, the second time slot starting at an earlier time in FIG. 9 will be referred to as second time slot A, and the second time slot starting at a later time will be referred to as second time slot B.

[0108] As illustrated in FIG. 8, the processing of step S10 is performed first, in the same manner as in FIG. 2.

[0109] Then, obtainer 120 obtains the first power unit price for the first time slot and the second power unit price for the second time slot (S12). Obtainer 120 obtains the first power unit price and the second power unit price stored in storage 150, for example.

[0110] As in Operation Example 2, the first power unit price is Y yen / kWh, and the second power unit price is X yen / kWh. The second power unit price is cheaper than the first power unit price.

[0111] Determiner 130 determines the following schedule based on the first power unit price and the second power unit price obtained by obtainer 120 and the usage start time included in each of the plurality of items of hot water supply information obtained by obtainer 120. Determiner 130 determines the schedule such that the electricity rate from the boiling by each of the plurality of water heaters 11 is reduced, and a time difference between a first expected completion time, which is the time at which the boiling by each of the plurality of water heaters 11 is expected to be completed, and the usage start time, is shortened (S32). In the present operation example, determiner 130 determines the schedule based on the first power unit price, the second power unit price, and the usage start time, to reduce the electricity rate from the boiling by first water heater 11a, and to shorten the time difference between the first expected completion time and the usage start time. In this manner, determiner 130 determines the schedule such that the time difference between the first expected completion time and the usage start time is shortened, and more specifically, determines the schedule such that the time difference is within a predetermined time period. The predetermined time period may be, for example, at least 30 minutes and no greater than 8 hours, and it is desirable that the predetermined time period be a time period determined by the manager of hot water supply system 100 in advance.

[0112] Step S32 will be described in more detail with reference to FIG. 9.

[0113] As described above, the second power unit price is cheaper than the first power unit price, and determiner 130 therefore determines the schedule such that the boiling by first water heater 11a is performed during the second time slot in which the power unit price is the lowest. Furthermore, determiner 130 determines a schedule in which if the boiling by first water heater 11a is not completed during the second time slot, the remaining boiling is performed during the first time slot, in which the power unit price is the second lowest. It is therefore possible that two schedules will be determined, as indicated in (a) and (b) of FIG. 9.

[0114] Furthermore, in the present operation example, the time at which second time slot B, which starts at a later time, ends, is the usage start time at which the owner starts using hot water, as illustrated in FIG. 9. The first expected completion time is the time at which boiling by water heater 11 (here, first water heater 11a) is completed in the schedule. In the example illustrated in (a) of FIG. 9, the first expected completion time is included in the first time slot, and in the example illustrated in (b) of FIG. 9, the first expected completion time is the time at which second time slot B has ended, and is included in second time slot B.

[0115] Determiner 130 then determines the schedule to reduce the time difference between the first expected completion time and the usage start time for first water heater 11a. The time difference between the first expected completion time and the usage start time in the schedule illustrated in (b) of FIG. 9 is shorter than the time difference between the first expected completion time and the usage start time in the schedule illustrated in (a) of FIG. 9. Determiner 130 therefore determines the schedule illustrated in (b) of FIG. 9 as a schedule that reduces the electricity rate from the boiling by first water heater 11a and reduces the time difference between the first expected completion time and the usage start time.

[0116] The processing of step S90 is then performed.

[0117] In Operation Example 3, the boiling by water heater 11 (e.g., first water heater 11a) is performed during a time slot in which the power unit price is lower, which makes it possible to reduce the electricity rate paid by the owner of water heater 11.

[0118] Additionally, for example, as indicated in (a) of FIG. 9, if the time from the first expected completion time to the usage start time is long, a problem arises in that the boiled water cools down. However, in Operation Example 3, as indicated in (b) of FIG. 9, the time difference between the first expected completion time and the usage start time is short, which makes it unlikely that the stated problem will arise.[Operation Example 4]

[0119] FIG. 10 is a flowchart of Operation Example 4 according to the present embodiment. FIG. 11 is a diagram illustrating a schedule of Operation Example 4 according to the present embodiment.

[0120] Operation Example 4 is operations in which, for example, in step S90 in Operation Example 1, controller 140 is controlling the boiling by the plurality of water heaters 11 (first and second water heaters 11a and 11b) in the second time slot based on the schedule determined. More specifically, these are operations in which first and second water heaters 11a and 11b are in the middle of boiling.

[0121] As described above, in Operation Example 1, obtainer 120 obtains the second used power, which corresponds to the expected power amount in the second time slot for the electrical equipment aside from the plurality of water heaters 11 in housing complex 40. However, it is also possible that an amount of power exceeding the expected power amount will be consumed. Operation Example 4 is operations performed under the assumption that in step S90, when boiling by the plurality of water heaters 11 is performed, the power amount of the electrical equipment aside from the plurality of water heaters 11 in housing complex 40 exceeds the expected power amount.

[0122] Obtainer 120 obtains the first used power, at the present time, of the electrical equipment in housing complex 40 aside from the plurality of water heaters 11 in the second time slot (step S13). Note that obtainer 120 obtains the first used power as follows.

[0123] In step S13, obtainer 120 obtains, through communicator 110, the individual dwelling power information about the power used by electrical equipment 12 and the common area power information about the power used by electrical equipment 21. As described above, in the present embodiment, the electrical equipment aside from the plurality of water heaters 11 is constituted by all of the plurality of electrical equipment 12 in the plurality of households and electrical equipment 21 in common area 20. The first used power is information that integrates the used power at the present time (the second time slot) for electrical equipment 12, indicated by the individual dwelling power information, and the used power at the present time (the second time slot) for electrical equipment 21, indicated by the common area power information.

[0124] In other words, by having obtainer 120 obtain the individual dwelling power information and the common area power information, obtainer 120 obtains the first used power, at the present time, of the electrical equipment aside from the plurality of water heaters 11 in housing complex 40, in the second time slot. The first used power can also be said to be a measured value of the power of the electrical equipment aside from the plurality of water heaters 11 at the present time (the second time slot).

[0125] Next, based on the boiling amount included in the plurality of items of hot water supply information and the first used power obtained, determiner 130 determines whether the overall demand power of housing complex 40 at the present time (the second time slot) exceeds the first reference power obtained (S23). In other words, in step S23, it is determined whether the demand power will still exceed the first reference power even if the start of boiling by any one water heater 11 is delayed in step S30 of Operation Example 1. In other words, determiner 130 predicts and determines whether the demand power will exceed the reference power based on the first used power, which is the measured value of the power of the electrical equipment aside from the plurality of water heaters 11, after the start of the second time slot (in step S23).

[0126] Furthermore, if it is determined that the demand power will exceed the first reference power in the second time slot (Yes in step S23), determiner 130 updates the schedule as follows, based on the determined schedule. That is, determiner 130 updates the schedule determined in step S30 to stop the boiling by water heater 11 for which the time difference between the second expected completion time and the third expected completion time is greatest (S33). Note that the second expected completion time is a time at which boiling indicated by the schedule determined in step S30 is expected to be completed. The third expected completion time is a time at which boiling is expected to be completed when boiling is started at the latest boiling start time.

[0127] The processing of step S33 will be described with reference to FIG. 11.

[0128] (a) of FIG. 11 is a diagram illustrating a schedule when it is determined that the demand power will exceed the first reference power. For example, as indicated in (a) of FIG. 11, at time t2 (the current time), the first used power for the electrical equipment aside from the plurality of water heaters 11 is obtained, and it is determined that the demand power will exceed the first reference power in the second time slot (and more specifically, after time t2). In such a case, determiner 130 updates the schedule to stop boiling by water heater 11, among the plurality of water heaters 11, for which the time difference between the second expected completion time and the third expected completion time is greatest.

[0129] The second expected completion time and the third expected completion time will be described in more detail here.

[0130] The second expected completion time is a time at which boiling by water heater 11 is expected to be completed, as indicated by the schedule determined in step S30, for example. For example, (a) of FIG. 11 indicates that the second expected completion time of first water heater 11a is t21, and the second expected completion time of second water heater 11b is t22. t21 and t22 are the same time.

[0131] The third expected completion time is a time at which boiling is expected to be completed when the boiling by water heater 11 is started at the latest boiling start time. For example, (a) of FIG. 11 indicates that the third expected completion time of first water heater 11a is t31, and the third expected completion time of second water heater 11b is t32. t31 is a time earlier than t32.

[0132] In step S33, determiner 130 updates the schedule to stop the boiling by water heater 11, among the plurality of water heaters 11 (here, first and second water heaters 11a and 11b), for which the time difference between the second expected completion time and the third expected completion time is greatest. As illustrated in (a) of FIG. 11, the time difference between the second expected completion time and the third expected completion time of second water heater 11b is greater than the time difference between the second expected completion time and the third expected completion time of first water heater 11a. Accordingly, determiner 130 updates the schedule to stop the boiling by second water heater 11b among first and second water heaters 11a and 11b. More specifically, determiner 130 updates the schedule to stop the boiling by second water heater 11b at current time t2.

[0133] (b) of FIG. 11 is a diagram illustrating the schedule in which the boiling by second water heater 11b has been stopped, i.e., the updated schedule. Note that the present embodiment is not limited to the example indicated in (b) of FIG. 11, and the boiling by the plurality of water heaters 11 may be stopped. Additionally, the first used power is obtained every set period of time (e.g., every five minutes), and a time slot in which the first used power decreases after t21 is present, the schedule may be updated so that the boiling by second water heater 11b is started again.

[0134] Compared to water heater 11 for which the time difference between the second expected completion time and the third expected completion time is small, for water heater 11 for which the time difference is large, even if the boiling is paused, the time from the time at which the boiling is paused to the expected usage time is long. Accordingly, compared to water heater 11 for which the time difference is small, for water heater 11 for which the time difference is large, even if the boiling is paused, performing the boiling again makes it more likely that the boiling will be completed by the usage start time. Accordingly, having determiner 130 update the schedule to stop the boiling by water heater 11 for which the time difference is large (e.g., second water heater 11b) makes it less likely that water heater 11 for which the time difference is small and water heater 11 for which the time difference is large will run out of hot water.

[0135] Furthermore, controller 140 controls the boiling by the plurality of water heaters 11 in the second time slot based on the schedule updated by determiner 130 in step S33 (S53a).

[0136] Note that if it is determined that the demand power will not exceed the first reference power in the second time slot (No in step S23), controller 140 performs the following processing. In this case, controller 140 controls the boiling by the plurality of water heaters 11 in the second time slot based on the schedule determined by determiner 130 in step S30 (S53b).

[0137] In Operation Example 4, if, during the second time slot, the demand power exceeds the first reference power, hot water supply system 100 suppresses situations where the demand power exceeds the first reference power by updating the schedule to stop the boiling by water heater 11 (second water heater 11b). In other words, hot water supply system 100 capable of suppressing the overall demand power (and more specifically, the maximum value of the demand power) of housing complex 40 is realized. Additionally, as described above, having determiner 130 update the schedule to stop the boiling by water heater 11 for which the time difference between the second expected completion time and the third expected completion time is large makes it less likely that water heater 11 for which the time difference is small and water heater 11 for which the time difference is large will run out of hot water.

[0138] In Operation Example 4, the schedule is updated in the second time slot, but the configuration is not limited thereto. For example, the schedule may be updated in the first time slot, and control of the boiling by the plurality of water heaters 11 may be performed in the first time slot. Additionally, for example, in the example illustrated in (b) of FIG. 1B, the schedule may be updated in a predetermined time slot (e.g., 12 PM to 2 PM), and the boiling by the plurality of water heaters 11 may be controlled in the predetermined time slot.[Operation Example 5]

[0139] FIG. 12 is a flowchart of Operation Example 5 according to the present embodiment. FIG. 13 is a diagram illustrating a schedule of Operation Example 5 according to the present embodiment.

[0140] Operation Example 5 is operations in which, for example, in step S90 in Operation Example 1, controller 140 is controlling the boiling by two or more water heaters 11 (first and second water heaters 11a and 11b) in the second time slot based on the schedule determined. More specifically, these are operations in which first and second water heaters 11a and 11b are in the middle of boiling.

[0141] Like Operation Example 4, Operation Example 5 is operations performed under the assumption that in step S90, when boiling by the two or more water heaters 11 is performed, the power amount of the electrical equipment aside from the plurality of water heaters 11 in housing complex 40 exceeds the expected power amount.

[0142] Obtainer 120 obtains the first used power, at the present time, of the electrical equipment in housing complex 40 aside from the plurality of water heaters 11 in the second time slot (step S13). As described above, the first used power can also be said to be a measured value of the power of the electrical equipment aside from the plurality of water heaters 11 at the present time (the second time slot).

[0143] Furthermore, obtainer 120 obtains a boiling instruction instructing boiling by an other water heater 11 other than the two or more water heaters 11 (first and second water heaters 11a and 11b) (S14). Here, it is assumed that other water heater 11 is third water heater 11c. The boiling instruction indicates the boiling amount of that water heater 11 (here, third water heater 11c).

[0144] For example, obtainer 120 may obtain the boiling instruction when an information processing device accepts an operation from the owner of third water heater 11c (i.e., the owner of third individual dwelling 10c). The information processing device is control device 13 owned by the owner, an information terminal such as a smartphone, a tablet, or a personal computer, or the like.

[0145] If the owner of third water heater 11c wishes to use hot water, they operate an acceptor of control device 13, which is an example of the information processing device. In other words, the acceptor accepts an operation instructing boiling by third water heater 11c. As a result, control device 13 outputs the boiling instruction to communicator 110 in accordance with the accepted operation. Obtainer 120 then obtains the boiling instruction obtained by communicator 110.

[0146] Note that by operating the information terminal such as a smartphone, a tablet, or a personal computer, which is an example of an information processing terminal, the owner of third water heater 11c may output the boiling instruction from the information terminal to control device 13. Through this, control device 13 obtains the boiling instruction that has been output, and outputs the boiling instruction obtained to communicator 110. Obtainer 120 then obtains the boiling instruction obtained by communicator 110.

[0147] In this manner, in step S14, obtainer 120 obtains the boiling instruction for third water heater 11c.

[0148] Based on the boiling amount included in the hot water supply information for the two or more water heaters 11, the first used power obtained, and the boiling instruction obtained, determiner 130 determines whether the overall demand power of housing complex 40 at the present time (the second time slot) exceeds the first reference power obtained (S24). In other words, determiner 130 makes this determination based on the boiling amounts of first and second water heaters 11a and 11b, the first used power, and the boiling amount of third water heater 11c included in the boiling instruction.

[0149] If the demand power is determined to exceed the first reference power in the second time slot (Yes in step S24), determiner 130 updates the schedule as follows, based on the schedule determined in step S30 and the boiling instruction obtained in step S14. That is, determiner 130 updates the schedule to stop boiling by water heater 11, among the two or more water heaters 11, for which the time difference between the second expected completion time and the third expected completion time is the greatest, and start boiling by other water heater 11 (S34a). In the present operation example, determiner 130 updates the schedule to stop the boiling by water heater 11, among first and second water heaters 11a and 11b, for which the time difference between the second expected completion time and the third expected completion time is greatest, and to start the boiling by third water heater 11c.

[0150] The processing of steps S24 and S34A will be described with reference to FIG. 13.

[0151] (a) of FIG. 13 is a diagram illustrating the schedule determined in step S30. (b) of FIG. 13 is a diagram illustrating a schedule in which the boiling by third water heater 11c is added to the schedule in which the boiling by first and second water heaters 11a and 11b is performed, indicated in (a) of FIG. 13. The schedule indicated in (b) of FIG. 13 is a diagram illustrating a schedule when it is determined that the demand power will exceed the first reference power. For example, as indicated in (b) of FIG. 13, the first used power for the electrical equipment aside from the plurality of water heaters 11 and the boiling instruction for third water heater 11c are obtained at time t2 (the current time). At this time, it is determined that the demand power will exceed the first reference power in the second time slot (and more specifically, after time t2). In such a case, determiner 130 updates the schedule to stop the boiling by water heater 11, among the two or more water heaters 11, for which the time difference between the second expected completion time and the third expected completion time is the greatest, and start the boiling by other water heater 11.

[0152] In step S34a, determiner 130 updates the schedule to stop the boiling by water heater 11, among the two or more water heaters 11 (here, first and second water heaters 11a and 11b), for which the time difference between the second expected completion time and the third expected completion time is greatest. As indicated in (b) of FIG. 13, the time difference between the second expected completion time and the third expected completion time of second water heater 11b is greater than the time difference between the second expected completion time and the third expected completion time of first water heater 11a. Accordingly, determiner 130 updates the schedule to stop the boiling by second water heater 11b among first and second water heaters 11a and 11b.

[0153] As in Operation Example 4, having determiner 130 update the schedule to stop the boiling by water heater 11 for which the time difference is large makes it less likely that water heater 11 for which the time difference is small and water heater 11 for which the time difference is large will run out of hot water.

[0154] In this manner, hot water supply system 100 suppresses situations where the demand power exceeds the first reference power by updating the schedule to stop the boiling by water heater 11 (second water heater 11b). In other words, hot water supply system 100 capable of suppressing the overall demand power (and more specifically, the maximum value of the demand power) of housing complex 40 is realized.

[0155] Furthermore, in step S34a, determiner 130 updates the schedule to start the boiling by other water heater 11 (third water heater 11c). More specifically, determiner 130 updates the schedule such that the boiling by third water heater 11c begins at time t2 or later. Note that determiner 130 preferably updates the schedule such that the boiling by third water heater 11c begins at an early time following time t2 (a time within several minutes from time t2, for example).

[0156] (c) of FIG. 13 is a diagram illustrating the schedule in which the boiling by second water heater 11b has been stopped and the boiling by third water heater 11c has been started, i.e., the updated schedule. As indicated in (c) of FIG. 13, the boiling by second water heater 11b, which has been paused, may be repeated after the end of the boiling by third water heater 11c.

[0157] Furthermore, controller 140 controls the boiling by the plurality of water heaters 11 in the second time slot based on the schedule updated by determiner 130 in step S34a (S54a).

[0158] If the demand power is determined not to exceed the first reference power in the second time slot (No in step S24), determiner 130 updates the schedule as follows, based on the schedule determined in step S30 and the boiling instruction obtained in step S14. That is, determiner 130 updates the schedule to start the boiling by other water heater 11 (S34b). Determiner 130 updates the schedule to be a schedule in which the boiling by third water heater 11c is added to the schedule in which the boiling by first and second water heaters 11a and 11b is performed, indicated in (a) of FIG. 13.

[0159] Next, controller 140 controls the boiling by the plurality of water heaters 11 in the second time slot based on the schedule updated by determiner 130 in step S34b (S54b).

[0160] In Operation Example 5, hot water supply system 100 performs the following processing when the boiling instruction of other water heater 11 (third water heater 11c) is obtained during the second time slot. That is, hot water supply system 100 updates the schedule to start the boiling by other water heater 11. Through this, hot water supply system 100 can perform the boiling by other water heater 11.

[0161] In Operation Example 4 and Operation Example 5, the boiling by second water heater 11b for which, among the plurality of water heaters 11 (first and second water heaters 11a and 11b), the time difference between the second expected completion time and the third expected completion time is greatest, is stopped, but the configuration is not limited thereto.

[0162] For example, the manager of hot water supply system 100 may obtain information about the stopping of boiling for each of the plurality of owners by conducting a questionnaire on the stopping of the boiling with the owners of first to fifth individual dwellings 10a to 10e. By controlling an information terminal such as a smartphone, a tablet, or a personal computer, the manager sends information about the stopping of the boiling to communicator 110 of hot water supply system 100. Obtainer 120 of hot water supply system 100 obtains the information about the stopping of the boiling. As described in Operation Example 4 and Operation Example 5, the questionnaire asks the owner whether it is acceptable to stop the boiling by water heater 11 owned by that owner when the overall demand power of housing complex 40 exceeds the first reference power obtained. Information about the stopping of boiling for one owner indicates whether it is acceptable to stop the boiling by water heater 11 owned by the one owner.

[0163] As one example, assume that the information about the stopping of boiling for the owner of first water heater 11a indicates that it is acceptable to stop the boiling by first water heater 11a. Furthermore, assume that the information about the stopping of boiling for the owner of second water heater 11b indicates that it is not acceptable to stop the boiling by second water heater 11b.

[0164] In such a case, in step S33 of Operation Example 4 and step S34a of Operation Example 5, determiner 130 performs the following processing. That is, based on the information about stopping the boiling for the owners of first water heater 11a and second water heater 11b, determiner 130 updates the schedule to stop the boiling by first water heater 11a among first water heater 11a and second water heater 11b. In other words, if the owner agrees to stop the boiling, the boiling by water heater 11 owned by that owner is stopped. If the owner does not agree to stop the boiling, the boiling by water heater 11 owned by that owner is not stopped. In other words, determiner 130 updates the schedule according to the owner's wishes.

[0165] In Operation Example 4 and Operation Example 5, stopping the boiling by water heater 11 may cause the boiling by that water heater 11 to be performed in a time slot having a higher power unit price (e.g., the first time slot). As a result, the electricity rate paid by the owner of water heater 11 will be higher than when the boiling by that water heater 11 is performed in a time slot having a lower power unit price. In such a case, a display of hot water supply system 100 displays the monetary amount of the difference between the electricity rate when the boiling by water heater 11 is performed in a time slot having a lower power unit price and the electricity rate when the boiling by water heater 11 is performed in a time slot having a higher power unit price. The manager of hot water supply system 100 can make the owner more amenable to cooperating with stopping of the boiling by paying the displayed monetary amount to the owner.

[0166] Furthermore, there are cases where the boiling by one water heater 11 is stopped and then performed in a time slot having a higher power unit price for a predetermined period of time (e.g., two days). Such cases are likely to occur especially in winter, when there is increased demand for hot water.

[0167] When such a case occurs, the following processing may be performed to suppress the electricity rate paid by the owners in housing complex 40 as a whole. That is, when such a case occurs, during one season including the predetermined period (e.g., winter), hot water supply system 100 deems that the boiling by water heater 11 is performed during a time slot having a higher power unit price. Hot water supply system 100 compares the monetary amount when the difference occurs throughout the one season, with the amount of the price increase in the electricity rate for the current year when a contract with a high base rate in the current month and the 11 months from the following month has been entered into due to the boiling by water heater 11 not being stopped and the demand power exceeding the first reference power. If hot water supply system 100 determines that the amount of the price increase is lower, the demand power is permitted to exceed the first reference power, and the first reference power is changed to a higher first reference power after that date. In other words, hot water supply system 100 determines a schedule based on the changed higher first reference power after the date.

[0168] Note that the predetermined period is not limited to two days, and may be, for example, several days, a week, or a month.

[0169] In Operation Example 5, the schedule is updated in the second time slot, but the configuration is not limited thereto. For example, the schedule may be updated in the first time slot, and control of the boiling by the plurality of water heaters 11 may be performed in the first time slot. Additionally, for example, in the example illustrated in (b) of FIG. 1B, the schedule may be updated in a predetermined time slot (e.g., 12 PM to 2 PM), and the boiling by the plurality of water heaters 11 may be controlled in the predetermined time slot.[Operation Example 6]

[0170] FIG. 14 is a flowchart of Operation Example 6 according to the present embodiment. FIG. 15 is a diagram illustrating a schedule of Operation Example 6 according to the present embodiment.

[0171] Operation Example 6 is operations in which, for example, after determiner 130 determines the schedule in step S30 in Operation Example 1, determiner 130 reviews and re-determines the schedule determined.

[0172] Operation Example 6 will describe an example in which two types of time slots having different power unit prices (first and second time slots) are provided, and a schedule for boiling by one water heater 11 (here, first water heater 11a) is determined. In the present operation example, two of the second time slots are provided for one day, i.e., a plurality of the second time slots are provided. For identification, the second time slot starting at an earlier time in FIG. 15 will be referred to as second time slot A, and the second time slot starting at a later time will be referred to as second time slot B.

[0173] After step S30 is performed, determiner 130 makes the following determination based on the usage start time included in each of the plurality of items of hot water supply information obtained by obtainer 120. In other words, determiner 130 determines whether the plurality of water heaters 11 include a first target water heater for which the time from the second expected completion time to the usage start time exceeds a reference time (S60). The second expected completion time is a time at which boiling indicated by the schedule determined by determiner 130 in step S30 is expected to be completed.

[0174] The reference time may be, for example, at least 30 minutes and no greater than 8 hours, and it is desirable that the predetermined time period be a time period determined by the manager of hot water supply system 100 in advance.

[0175] Furthermore, if the first target water heater for which the time from the second expected completion time to the usage start time exceeds the reference time is determined to be present (Yes in step S60), determiner 130 performs the following processing. In other words, determiner 130 re-determines the schedule to temporarily stop the boiling by the first target water heater in the second time slot, start the boiling again, and complete the boiling by the first target water heater by the usage start time (S70).

[0176] The processing of steps S60 and S70 will be described with reference to FIG. 15.

[0177] (a) in FIG. 15 is a diagram illustrating a schedule when it is determined that the first target water heater (here, first water heater 11a) is present when the time from the second expected completion time to the usage start time exceeds the reference time. (a) of FIG. 15 is a diagram illustrating the schedule determined in step S30 of Operation Example 1, for example.

[0178] Additionally, for example, as indicated in (a) of FIG. 15, if the time from the second expected completion time to the usage start time exceeds the reference time, i.e., if the time from the second expected completion time to the usage start time is long, a problem arises in that the boiled water cools down. Accordingly, determiner 130 re-determines the schedule such that in the second time slot (here, second time slot A), the boiling by the first target water heater is stopped temporarily, and in the second time slot (here, second time slot B), the boiling is performed again. At this time, determiner 130 re-determines the schedule such that the time from the time when the boiling by the first target water heater is completed to the expected usage time drops below the reference time due to the boiling being performed again.

[0179] (b) of FIG. 15 is a diagram illustrating the schedule in which the boiling by first water heater 11a is temporarily stopped and the boiling is performed again, i.e., the re-determined schedule. Note that the configuration is not limited to the example indicated in (b) of FIG. 15, and in the present operation example, if a plurality of first target water heaters are present, determiner 130 performs the following processing. That is, determiner 130 may re-determine the schedule to temporarily stop the boiling by the plurality of first target water heaters after that boiling, and then start the boiling again such that the boiling by the plurality of first target water heaters is completed by the usage start time.

[0180] Furthermore, controller 140 controls the boiling by the plurality of water heaters 11 in the second time slot based on the schedule re-determined by determiner 130 in step S70 (S90).

[0181] Note that if the first target water heater for which the time from the second expected completion time to the usage start time exceeds the reference time is determined not to be present (No in step S60), controller 140 performs the following processing. In this case, controller 140 controls the boiling by the plurality of water heaters 11 in the second time slot based on the schedule determined by determiner 130 in step S30 (S90).

[0182] In addition, as illustrated in FIG. 15, in the present operation example, the second expected completion time is included in the first time slot in the schedule determined in step S30. In this schedule, the electricity rate increases compared to when the boiling by the first target water heater (first water heater 11a) is completed in the second time slot alone.

[0183] Accordingly, if the second expected completion time is included in the first time slot, determiner 130 may re-determine the schedule such that the boiling by the first target water heater (first water heater 11a) is completed in the second time slot only. Specifically, as illustrated in (b) of FIG. 15, determiner 130 re-determines the schedule such that when the boiling by the first target water heater (first water heater 11a) is not completed in second time slot A alone, the boiling is performed in second time slot B as well.

[0184] In Operation Example 6, two of the second time slots (second time slot A and second time slot B) are provided for one day, i.e., a plurality of the second time slots are provided, but the same processing may be performed even if only one of the second time slots is provided for one day. In other words, if determiner 130 determines that the first target water heater for which the time from the second expected completion time to the usage start time exceeds the reference time is present, the following processing is performed. Determiner 130 re-determines the schedule such that in one second time slot, the boiling by the first target water heater is stopped temporarily, and the boiling is performed again in that second time slot.

[0185] As indicated in (b) of FIG. 15, in Operation Example 6, the schedule is re-determined by determiner 130 to temporarily stop the boiling by the first target water heater, start the boiling again, and complete the boiling by the first target water heater by the usage start time. Note that determiner 130 re-determines the schedule such that the time from the time when the boiling by the first target water heater is completed to the expected usage time drops below the reference time due to the boiling being performed again. Accordingly, because the time from the time when the boiling by the first target water heater is completed to the expected usage time is sufficiently shortened, the problem that the boiled water cools down due to the time from the time when the boiling is completed (the second expected completion time) to the expected usage start time being long is unlikely to occur.[Operation Example 7]

[0186] FIG. 16 is a flowchart of Operation Example 7 according to the present embodiment.

[0187] Like Operation Example 6, Operation Example 7 is operations in which, for example, after determiner 130 determines the schedule in step S30 in Operation Example 1, determiner 130 reviews and re-determines the schedule determined.

[0188] As illustrated in FIG. 16, in Operation Example 7, after step S30 is performed, determiner 130 makes the following determination. In other words, determiner 130 determines whether the plurality of water heaters 11 include a second target water heater for which a boiling number indicated by the schedule determined by determiner 130 in step S30 is at least a predetermined number (S61).

[0189] "Boiling number" refers to the number of times water heater 11 performs boiling before the target boiling amount is reached. For example, in (a) of FIG. 15, the boiling number of first water heater 11a is one time, and in (b) of FIG. 15, the boiling number of first water heater 11a is two times. The predetermined number may be, for example, at least three times and no greater than ten times.

[0190] Furthermore, if a second target water heater having a boiling number that is at least the predetermined number is determined to be present (Yes in step S61), determiner 130 re-determines the schedule such that the boiling number of the second target water heater drops below the predetermined number (S71).

[0191] Furthermore, controller 140 controls the boiling by the plurality of water heaters 11 in the second time slot based on the schedule re-determined by determiner 130 in step S71 (S90).

[0192] Note that if a second target water heater for which the boiling number is at least the predetermined number is determined not to be present (No in step S61), controller 140 performs the following processing. In this case, controller 140 controls the boiling by the plurality of water heaters 11 in the second time slot based on the schedule determined by determiner 130 in step S30 (S90).

[0193] As described above, the predetermined number may be, for example, at least three times and no greater than ten times. As the number of instances of boiling increases, the boiling efficiency when water heater 11 is started up decreases, causing a problem that the amount of consumed power increases. In Operation Example 7, the boiling number of the second target water heater is less than the predetermined number, and thus such a problem is unlikely to occur. In other words, the amount of consumed power is suppressed, and thus hot water supply system 100 can suppress the overall demand power (and more specifically, the maximum value of the demand power) of housing complex 40.

[0194] In Operation Example 7, the schedule is re-determined in the first time slot, but the configuration is not limited thereto. For example, the schedule may be re-determined in the second time slot, and control of the boiling by the plurality of water heaters 11 may be performed in the first time slot. In the example illustrated in (b) of FIG. 1B, for example, the schedule may be re-determined by the start of a predetermined time slot (e.g., 12 PM to 2 PM), and the control of the boiling by the plurality of water heaters 11 may be performed in the predetermined time slot.[Operation Example 8]

[0195] FIG. 17 is a flowchart of Operation Example 8 according to the present embodiment. FIG. 18 is a diagram illustrating a schedule and an electricity rate of Operation Example 8 according to the present embodiment.

[0196] Like Operation Examples 6 and 7, Operation Example 8 is operations in which, for example, after determiner 130 determines the schedule in step S30 in Operation Example 1, determiner 130 reviews and re-determines the schedule determined.

[0197] In Operation Example 8, step S30 is performed, as illustrated in FIG. 17. Then, if determiner 130 determines that the second expected completion time of the boiling by third water heater 11c, for which the start of boiling was delayed in the schedule determined by determiner 130 in step S30, falls within the first time slot, determiner 130 performs the following processing. That is, determiner 130 determines whether a second price increase is lower than a first price increase (S62). As described above, the second time slot is from 11 PM to 7 AM the next day. In other words, the second expected completion time of the boiling by third water heater 11c falling within the first time slot means that the second expected completion time falls within the first time slot of the next day (from 7 AM on the next day to 11 PM on the next day).

[0198] The first price increase and the second price increase will be described here with reference to FIG. 18.

[0199] FIG. 18 is a diagram illustrating a schedule re-determined through the processing of Operation Example 8 according to the present embodiment. More specifically, (a) of FIG. 18 is a diagram illustrating a schedule in which the second expected completion time of the boiling by third water heater 11c, for which the start of boiling has been delayed, is included in the first time slot. (b) of FIG. 18 is a diagram illustrating a schedule when a demand power (rate Pb) exceeds a first reference power (rate Pa).

[0200] The first price increase will be described with reference to (a) of FIG. 18.

[0201] As described above, the first time slot is a time slot in which the power unit price is higher, and the second time slot is a time slot in which the power unit price is lower.

[0202] As indicated in (a) of FIG. 18, if the second expected completion time of the boiling by third water heater 11c falls within the first time slot, the electricity rate paid by the owner of third water heater 11c will be higher than if the boiling by third water heater 11c ends in the second time slot. The first price increase is a price increase in the electricity rate due to the second expected completion time of the boiling by third water heater 11c falling within the first time slot, compared to the electricity rate when the second expected completion time falls within the second time slot.

[0203] For example, assume that the power unit price in the second time slot is X (yen / kWh), the power unit price in the first time slot is Y (yen / kWh), and the power amount required by third water heater 11c to boil within the first time slot, indicated in (a) of FIG. 18, is W (kWh). In this case, the first price increase is expressed by Formula (1). W × Y − X

[0204] The second price increase will be described next with reference to (b) of FIG. 18.

[0205] The second price increase is an increase in the electricity rate due to the demand power (rate Pb) exceeding the first reference power (rate Pa) when the boiling by third water heater 11c is performed such that the second expected completion time of the boiling by third water heater 11c falls within the second time slot.

[0206] For example, assuming the rate at the demand power is Pb (yen) and the rate at the first reference power is Pa (yen), the second price increase for the boiling by third water heater 11c, indicated in (b) of FIG. 18, is expressed by Formula (2). Pb − Pa

[0207] Pb (yen), which is the rate at the demand power, is a rate that needs to be paid to the power company, for example, when the overall demand power is required by housing complex 40 in the event that the demand power exceeds the first reference power. The rate at the first reference power, namely Pa (yen), is a rate that needs to be paid to the power company, for example, when the overall demand power is required by housing complex 40 in the event that the demand power does not exceed the first reference power.

[0208] As illustrated in FIG. 17, when the second price increase is lower than the first price increase (yes in S62), determiner 130 increases the first reference power, and re-determines the schedule such that the second expected completion time of the boiling by third water heater 11c falls within the second time slot (S72). In other words, in this case, determiner 130 changes the reference power such that the reference power increases from the first reference power (rate Pa) to the first reference power (rate Pc) after the change and the demand power (rate Pb) becomes lower than the first reference power (rate Pc) after the change. As a result, determiner 130 re-determines the schedule to be the schedule indicated in (b) of FIG. 18.

[0209] Furthermore, controller 140 controls the boiling by the plurality of water heaters 11 in the second time slot based on the schedule re-determined by determiner 130 in step S72 (S90).

[0210] Note that if the second price increase is at least the first price increase (No in S62), controller 140 performs the following processing. In this case, controller 140 controls the boiling by the plurality of water heaters 11 in the second time slot based on the schedule determined by determiner 130 in step S30 (S90).

[0211] In Operation Example 8, by comparing the first price increase with the second price increase, hot water supply system 100 can re-determine the schedule such that the electricity rate is lower throughout the year.[Operation Example 9]

[0212] FIG. 19 is a flowchart of Operation Example 9 according to the present embodiment. FIG. 20 is a diagram illustrating a schedule of Operation Example 9 according to the present embodiment.

[0213] Like Operation Example 4, Operation Example 9 is operations in which, for example, in step S90 in Operation Example 1, controller 140 is controlling the boiling by the plurality of water heaters 11 (first to fourth water heaters 11a to 11d) in the second time slot based on the schedule determined. More specifically, these are operations in which first and second water heaters 11a and 11b are boiling, and as will be described later, at the time when step S25 according to Operation Example 9 is performed, third and fourth water heaters 11c and 11d are not yet boiling.

[0214] Operation Example 9 describes an example in which the second time slot includes a partial time slot, as illustrated in FIG. 20. As described above, the second time slot is from 11 PM to 7 AM the next day. The partial time slot is, for example, from 2 AM the next day to 4 AM the next day in the second time slot, but is not limited thereto.

[0215] The partial time slot will be described further.

[0216] There are cases where the need to conserve power rises sharply due to tight supply and demand of electricity or soaring electricity market prices. In such cases, it may be necessary to keep the demand power below the first reference power, or keeping the demand power below the first reference power may keep the electricity rate lower. In the present operation example, a time slot in which the reference power is set to be less than the first reference power in this manner is the partial time slot. It should be noted that it is often difficult to determine whether the need to conserve power will increase before the start of the second time slot. Accordingly, Operation Example 9 will be described assuming that at a stage such as step S30 of Operation Example 1 before Operation Example 9 is performed, the first reference power is used and the schedule is determined under the assumption that no such partial time slot will occur.

[0217] Furthermore, obtainer 120 obtains the second reference power for the partial time slot (S15). Obtainer 120 obtains the second reference power stored in storage 150. The second reference power is a reference power lower than the first reference power and is a reference power for housing complex 40 (the plurality of residences). Furthermore, the second reference power is also a reference power for the partial time slot included in the second time slot.

[0218] Note that before step S15 is performed, hot water supply system 100 may perform the following processing. As described above, if the need to conserve power rises sharply, an information terminal such as a smartphone, a tablet, or a personal computer accepts a predetermined operation from the manager of hot water supply system 100. The predetermined operation is an operation instructing obtainer 120 of hot water supply system 100 to obtain the second reference power. The information terminal sends information instructing obtainer 120 to obtain the second reference power to communicator 110 of hot water supply system 100. Obtainer 120 may obtain the second reference power in step S15 by obtaining that information from communicator 110 of hot water supply system 100.

[0219] Furthermore, determiner 130 determines whether the overall demand power of housing complex 40 (the plurality of residences) has exceeded the second reference power obtained by obtainer 120 in the partial time slot in the schedule determined in step S30 (S25). As described above, the schedule determined in step S30 is determined without using the second reference power, and the second reference power may therefore be exceeded in that schedule. In this manner, it can also be said that in Operation Example 9, the reference power is changed from the first reference power to the second reference power.

[0220] Next, if determiner 130 determines that the demand power will exceed the second reference power (Yes in S25), determiner 130 updates the schedule determined by determiner 130 in step S30 prior to the partial time slot, which here is the second time slot. In other words, determiner 130 updates the schedule to start boiling in order from water heater 11, among the plurality of water heaters 11, for which the latest boiling start time is earliest (S35). More specifically, determiner 130 updates the schedule to start the boiling in order from water heater 11 for which the latest boiling start time is the earliest, among the plurality of water heaters 11 that have not yet started the boiling at the time of step S25. As described above, at the time when Operation Example 9 begins, two or more water heaters 11 (first and second water heaters 11a and 11b) are boiling. Accordingly, in step S35, determiner 130 updates the schedule to start boiling in order from water heater 11, among the plurality of water heaters 11, which is not one of the two or more water heaters 11 and for which the latest boiling start time is earliest.

[0221] Step S25 and step S35 will be described in more detail with reference to FIG. 20. For example, the time at which the processing of step S25 is being performed (the current time) is time t2, illustrated in FIG. 20. In addition, in the schedule illustrated in FIG. 20, the latest boiling start time of first water heater 11a is t11, the latest boiling start time of second water heater 11b is t12, the latest boiling start time of third water heater 11c is t13, and the latest boiling start time of fourth water heater 11d is t14. t11 is a time earlier than t12, t12 is a time earlier than t13, and t13 is a time earlier than t14.

[0222] (a) of FIG. 20 is a diagram illustrating the schedule determined in step S30. The schedule indicated in (b) of FIG. 20 is a diagram illustrating a schedule when it is determined that the demand power will exceed the second reference power. (b) of FIG. 20 is a diagram illustrating a schedule in which the boiling by third water heater 11c, for which the latest boiling start time is the earliest among the plurality of water heaters 11 that have not yet started boiling at time t2 (third and fourth water heaters 11c and 11d), starts earlier. In other words, (b) of FIG. 20 is a diagram illustrating the updated schedule.

[0223] For example, as indicated in (a) of FIG. 20, it is determined that the demand power will exceed the second reference power in the partial time slot at time t2 (the current time). In such a case, in step S35, determiner 130 updates the schedule to start boiling in order from water heater 11, among the plurality of water heaters 11, for which the latest boiling start time is earliest.

[0224] Determiner 130 updates the schedule such that the boiling by third water heater 11c, for which the latest boiling start time is earliest among third and fourth water heaters 11c and 11d, starts earlier, and the boiling by fourth water heater 11d, for which the latest boiling start time is later, starts later. Here, determiner 130 updates the schedule such that the boiling by third water heater 11c starts in the partial time slot. Additionally, to prevent the demand power from exceeding the second reference power in the partial time slot, determiner 130 updates the schedule such that the boiling by fourth water heater 11d starts in the second time slot after the partial time slot.

[0225] Furthermore, controller 140 controls the boiling by the plurality of water heaters 11 in the second time slot including the partial time slot based on the schedule updated by determiner 130 in step S35 (S95a).

[0226] Note that if it is determined that the demand power will not exceed the second reference power in the second time slot (No in S25), controller 140 performs the following processing. In this case, controller 140 controls the boiling by the plurality of water heaters 11 in the second time slot including the partial time slot based on the schedule determined by determiner 130 in step S30 (S95b).

[0227] Operation Example 9 describes operations in which the reference power is changed from the first reference power to the second reference power when the need to conserve power rises sharply due to tight supply and demand of electricity or soaring electricity market prices.

[0228] Then, if determiner 130 determines that the demand power will exceed the second reference power in the partial time slot where the reference power has been changed to the second reference power (Yes in S25), determiner 130 determines the following schedule. Determiner 130 determines a schedule that starts boiling in order from water heater 11 for which the latest boiling start time is the earliest among the plurality of water heaters 11.

[0229] Through this, in Operation Example 9, hot water supply system 100 capable of suppressing the overall demand power (and more specifically, the maximum value of the demand power) of housing complex 40 is realized. For example, as indicated in (b) of FIG. 20, situations where the maximum value of the demand power exceeds the second reference power are suppressed. This makes it less likely that the base rate for housing complex 40 will rise.

[0230] In addition, as described above, the reference power being changed from the first reference power to the second reference power is equivalent to a case where there is demand to conserve power due to tightening in the electricity supply and demand. Even in such a case, hot water supply system 100 can suppress the overall demand power (and more specifically, the maximum value of the demand power) of housing complex 40, and can meet the societal need to conserve electricity.[Operation Example 10]

[0231] FIG. 21 is a flowchart of Operation Example 10 according to the present embodiment.

[0232] Operation Example 10, illustrated in FIG. 21, will describe an example in which the schedule is re-determined such that power is supplied from power supply equipment 23 in the second time slot.

[0233] In Operation Example 10, first, step S30 described in Operation Example 1 is performed, and the schedule is determined.

[0234] Next, based on the schedule determined in step S30 and the first reference power obtained, determiner 130 determines whether the overall demand power of housing complex 40 will exceed the obtained first reference power in the second time slot (S63). In other words, in step S63, it is predicted and determined whether the demand power will still exceed the first reference power even if the start of boiling by third water heater 11c is delayed in step S30 of Operation Example 1.

[0235] Furthermore, if it is determined that the demand power will exceed the first reference power in the second time slot (Yes in S63), determiner 130 re-determines the schedule to supply power from power supply equipment 23 provided in housing complex 40 to housing complex 40 (S73).

[0236] Here, determiner 130 re-determines the schedule to supply power from power supply equipment 23 to housing complex 40 by the amount by which the demand power exceeds the first reference power. The sum of the power supplied by the power company and the power supplied by power supply equipment 23 is equivalent to the demand power. In other words, because the power supplied by the power company is equivalent to the first reference power, situations where the power supplied by the power company exceeds the first reference power are suppressed even if the demand power exceeds the first reference power.

[0237] Furthermore, controller 140 controls the boiling by the plurality of water heaters 11 in the second time slot based on the schedule determined by determiner 130 in step S73 (S90).

[0238] Note that if it is determined that the demand power will not exceed the first reference power in the second time slot (No in S63), controller 140 performs the following processing. In this case, controller 140 controls the boiling by the plurality of water heaters 11 in the second time slot based on the schedule determined by determiner 130 in step S30 (S90).

[0239] In Operation Example 10, if it is determined that the demand power will exceed the first reference power, the schedule is re-determined such that power is supplied from power supply equipment 23 to housing complex 40. Accordingly, situations where the power supplied by the power company exceeds the first reference power are suppressed. This makes it less likely that the electricity rate for housing complex 40 will rise.

[0240] Additionally, in Operation Example 10, if it is determined that the demand power will exceed the first reference power (Yes in S63), determiner 130 re-determines the schedule to supply power from power supply equipment 23 provided in housing complex 40 to housing complex 40, but the configuration is not limited thereto. In this case, for example, determiner 130 may re-determine the schedule to stop electrical equipment 21 (lighting, elevators, and the like) or the like of common area 20. Accordingly, the demand power is reduced, and thus situations where the power supplied by the power company exceeds the first reference power are suppressed.[Operation Example 11]

[0241] FIG. 22 is a flowchart of Operation Example 11 according to the present embodiment.

[0242] Operation Example 11, illustrated in FIG. 22, will describe an example in which the schedule is re-determined such that power is supplied from power supply equipment 23 in the first time slot.

[0243] In Operation Example 11, first, step S30 described in Operation Example 1 is performed, and the schedule is determined.

[0244] Next, determiner 130 determines whether the second expected completion time of boiling by at least one of water heaters 11 falls within the first time slot in the schedule determined in step S30 (S64). Here, the at least one water heater 11 is third water heater 11c for which the start of boiling is delayed in the schedule determined.

[0245] As described above, the second time slot is from 11 PM to 7 AM the next day. In other words, the second expected completion time of the boiling by third water heater 11c, for which the start of the boiling has been delayed, falling within the first time slot means that the second expected completion time falls within the first time slot on the next day (from 7 AM on the next day to 11 PM on the next day).

[0246] Furthermore, if it is determined that the second expected completion time of the boiling by third water heater 11c falls within the first time slot (Yes in S64), determiner 130 re-determines the schedule as follows (S74). In this case, determiner 130 re-determines the schedule to supply power from power supply equipment 23 provided by housing complex 40 for the boiling by third water heater 11c in the first time slot. Here, determiner 130 re-determines the schedule such that all the power required for the boiling by third water heater 11c in the first time slot is supplied from power supply equipment 23. In other words, it is not necessary for power to be supplied from the power company to housing complex 40 for the boiling by third water heater 11c in the first time slot.

[0247] Furthermore, controller 140 controls the boiling by the plurality of water heaters 11 in the second time slot based on the schedule determined by determiner 130 in step S74 (S90).

[0248] Note that if it is determined that the second expected completion time of the boiling by third water heater 11c does not fall within the first time slot (No in S64), controller 140 performs the following processing. In this case, controller 140 controls the boiling by the plurality of water heaters 11 in the second time slot based on the schedule determined by determiner 130 in step S30 (S90).

[0249] In Operation Example 11, if the second expected completion time of the boiling by third water heater 11cs within the first time slot, the schedule is re-determined to supply power from power supply equipment 23 for the boiling. It is therefore not necessary for power to be supplied from the power company to housing complex 40 for the boiling. This makes it possible to keep the electricity rate for housing complex 40 low.[Operation Example 12]

[0250] FIG. 23 is a flowchart of Operation Example 12 according to the present embodiment.

[0251] Operation Example 12, illustrated in FIG. 23, will describe an example in which fifth water heater 11e boils in the first time slot.

[0252] As an example, the processing of Operation Example 12 begins when obtainer 120 obtains, in the first time slot, a boiling instruction for fifth water heater 11e, included in the plurality of water heaters 11, from the owner of fifth water heater 11e. In other words, in Operation Example 12, it is necessary for fifth water heater 11e to boil in the first time slot.

[0253] First, when boiling by fifth water heater 11e is to be performed in the first time slot, determiner 130 determines the lowest price among a first price, a second price, and a third price (S80). The first price, the second price, and the third price will be described here.

[0254] The "first price" refers to a price when the boiling by fifth water heater 11e is performed using power supplied by the power company. In other words, the first price is the price paid to the power company when fifth water heater 11e boils using the power supplied by the power company.

[0255] When the boiling by fifth water heater 11e is performed using power with which charging equipment provided in housing complex 40 was charged (and more specifically, charging equipment included in power supply equipment 23), the price required to recharge the charging equipment is the "second price". In other words, the second price is the price for purchasing power supplied by the power company to recharge the power consumed due to the charging equipment discharging power for fifth water heater 11e to boil.

[0256] When the power required for the boiling by fifth water heater 11e is generated by solar power generation equipment provided in housing complex 40, the selling price of that generated power is the "third price". In other words, if the power required for the boiling by fifth water heater 11e has been generated by the solar power generation equipment, the third price is the price at which that power is sold to the power company, assuming the power is not consumed for boiling.

[0257] Furthermore, if it is determined in step S80 that the first price is lowest among the first price, the second price, and the third price, determiner 130 determines a control signal such that fifth water heater 11e boils using the power supplied by the power company (S81).

[0258] If it is determined in step S80 that the second price is lowest among the first price, the second price, and the third price, determiner 130 determines the control signal such that fifth water heater 11e boils using the power with which the charging equipment has been charged (S82).

[0259] If it is determined in step S80 that the third price is lowest among the first price, the second price, and the third price, determiner 130 determines the control signal such that fifth water heater 11e boils using the power generated by the solar power generation equipment (S83).

[0260] Furthermore, controller 140 controls the boiling by fifth water heater 11e based on the control signals determined by determiner 130 in steps S81, S82 and S83 (S84). More specifically, controller 140 controls communicator 110 to output the determined control signal to control device 13 of fifth individual dwelling 10e. Through this, control device 13 controls the boiling by fifth water heater 11e based on the obtained control signal.

[0261] In Operation Example 12, controller 140 controls the boiling by fifth water heater 11e to ensure the lowest amount of monetary loss. This makes it possible to minimize the monetary loss for the manager of housing complex 40.(Variation 1)

[0262] Variation 1 on the embodiment will be described next. The following descriptions will focus on the differences from the embodiment, and descriptions of common points will be omitted or simplified.

[0263] In the embodiment, hot water supply system 100 is installed in housing complex 40, but the configuration is not limited thereto. In the present variation, hot water supply system 100 is installed in region 340 including housing complex 40.[Configuration]

[0264] FIG. 24 is a block diagram illustrating the functional configuration of hot water supply system 100 according to Variation 1 on the embodiment.

[0265] Hot water supply system 100 is a system installed in region 340 including housing complex 40, a plurality of detached houses 410, and a plurality of facilities 520. Accordingly, FIG. 24 is a block diagram also illustrating functional configuration of each of housing complex 40, the plurality of detached houses 410, and the plurality of facilities 520 included in region 340.

[0266] Hot water supply system 100 suppresses a maximum value of the overall demand power of region 340 by controlling a plurality of water heaters 411 installed in the plurality of detached houses 410 and a plurality of water heaters 11 installed in a plurality of households included in housing complex 40. Note that the plurality of residences according to the present variation include the plurality of detached houses 410 and the plurality of households included in housing complex 40.

[0267] In region 340 according to the present variation, a high-voltage collective power reception contract is selected as the type of contract for supplying power to region 340.

[0268] Hot water supply system 100 according to the present variation determines a schedule for boiling by the plurality of water heaters 411 and the plurality of water heaters 11 before the start of the second time slot, i.e., during the first time slot. Hot water supply system 100 controls the plurality of water heaters 411 and the plurality of water heaters 11 based on the schedule determines.

[0269] Detached house 410 is an example of a residence constructed in region 340. Each of the plurality of detached houses 410 includes water heater 411, electrical equipment 412, control device 413, and power supply equipment 423. Water heater 411, electrical equipment 412, control device 413, and power supply equipment 423 have the same functions as water heater 11, electrical equipment 12, control device 13, and power supply equipment 23 described in the embodiment, respectively.

[0270] Accordingly, control device 413 can perform the same information processing as control device 13. Control device 413 installed in one detached house 410 can output information, such as the hot water supply information about water heater 411 installed in that one detached house 410, to communicator 110. Additionally, control device 413 installed in one detached house 410 can output information, such as power information about electrical equipment 412 installed in that one detached house 410 (equivalent to the individual dwelling power information of the embodiment), to communicator 110.

[0271] Facility 520 is a facility constructed in region 340, and is, for example, a commercial facility, an industrial facility, a school, a public facility, or the like. Each of the plurality of facilities 520 includes electrical equipment 521, power measurement device 522, and power supply equipment 523. Electrical equipment 521, power measurement device 522, and power supply equipment 523 have the same functions as electrical equipment 21, power measurement device 22, and power supply equipment 23 described in the embodiment, respectively.

[0272] Accordingly, power measurement device 522 can perform the same information processing as power measurement device 22. Power measurement device 522 installed in one facility 520 can output information, such as power information about electrical equipment 521 installed in that one facility 520 (equivalent to the common area power information of the embodiment), to communicator 110.

[0273] As a result, hot water supply system 100 according to Variation 1 can also perform Operation Examples 1 to 12 described in the embodiment.(Variation 2)

[0274] Variation 2 on the embodiment will be described next. The following descriptions will focus on the differences from the embodiment, and descriptions of common points will be omitted or simplified.

[0275] In the embodiment, hot water supply system 100 obtains information from control device 13 and power measurement device 22, but the configuration is not limited thereto. In the present variation, hot water supply system 100 obtains information from water heater 11, smart meter 15, power supply equipment 23, and smart meter 25.[Configuration]

[0276] FIG. 25 is a block diagram illustrating the functional configuration of hot water supply system 100 according to Variation 2 on the embodiment.

[0277] In the present variation, each of a plurality of households includes water heater 11 and smart meter 15. Each of the plurality of households does not include control device 13.

[0278] Water heater 11 according to the present variation outputs information, such as the hot water supply information about that water heater 11, to hot water supply system 100.

[0279] Smart meter 15 is a device that can measure the power usage amount by a household every predetermined time period (e.g., 30 minutes), and has a communication function. In other words, smart meter 15 can measure the power used by electrical equipment 12 (not shown), and can output the individual dwelling power information to hot water supply system 100.

[0280] In the present variation, smart meter 25 and power supply equipment 23 are installed in common area 20. Power measurement device 22 is not installed in common area 20.

[0281] Power supply equipment 23 according to the present variation outputs power supply equipment information, indicating a power generation amount, a charging amount, and the like by power supply equipment 23, to hot water supply system 100.

[0282] Smart meter 25 is a device that can measure the power usage amount by common area 20 every predetermined time period (e.g., 30 minutes), and has a communication function. In other words, smart meter 25 can measure the power used by electrical equipment 21 (not shown), and can output the common area power information to hot water supply system 100.

[0283] As a result, hot water supply system 100 according to Variation 2 can also perform Operation Examples 1 to 12 described in the embodiment.(Variation 3)

[0284] Variation 3 on the embodiment will be described next. The following descriptions will focus on the differences from Variations 1 and 2, and descriptions of common points will be omitted or simplified.[Configuration]

[0285] FIG. 26 is a block diagram illustrating the functional configuration of hot water supply system 100 according to Variation 3 on the embodiment.

[0286] In Variation 1, hot water supply system 100 obtains information from control devices 13 and 413 and power measurement devices 22 and 522, but the configuration is not limited thereto. In the present variation, hot water supply system 100 obtains information from water heaters 11 and 411, smart meters 15, 25, 415, and 525, and power supply equipment 23, 423, and 523.

[0287] Hot water supply system 100 according to Variation 3 can therefore also perform Operation Examples 1 to 12 described in the embodiment.(Effects, Etc.)

[0288] Invention 1 is hot water supply system 100, including: obtainer 120 that obtains a plurality of items of hot water supply information, each including a boiling amount of water heater 11 and a usage start time of water heater 11, and a first reference power of a plurality of residences in which a plurality of water heaters 11 are respectively installed, each of the plurality of water heaters 11 being water heater 11; determiner 130 that, based on the boiling amount included in each of the plurality of items of hot water supply information obtained, determines a schedule for starting boiling in order from water heater 11, among the plurality of water heaters 11, for which a latest boiling start time is earliest, when starting boiling by the plurality of water heaters 11 simultaneously is determined to cause an overall demand power of the plurality of residences to exceed the first reference power obtained, the latest boiling start time being a latest time to start boiling to ensure hot water does not run out at the usage start time included in the hot water supply information for that water heater 11; and controller 140 that controls boiling by the plurality of water heaters 11 based on the schedule determined.

[0289] Through this, as described in Operation Example 1, hot water supply system 100 capable of suppressing the overall demand power (and more specifically, the maximum value of the demand power) of a plurality of residences (housing complex 40, in Operation Example 1) is realized. For example, as indicated in (b) of FIG. 3, situations where the maximum value of the demand power exceeds the first reference power are suppressed. This makes it less likely that the base rate for housing complex 40 will rise.

[0290] Invention 2 is hot water supply system 100 according to Invention 1, wherein among a first time slot and a second time slot in which a power unit price is lower than in the first time slot, obtainer 120 obtains the first reference power in the second time slot; determiner 130 determines, before the second time slot, the schedule for starting the boiling in order from water heater 11 for which the latest boiling start time is earliest, when starting boiling by the plurality of water heaters 11 simultaneously in the second time slot is determined to cause the overall demand power of the plurality of residences to exceed the first reference power obtained; and controller 140 controls boiling by the plurality of water heaters 11 in the second time slot based on the schedule determined.

[0291] Through this, as described in Operation Example 1, the boiling by the plurality of water heaters 11 is performed in the second time slot in which the power unit price is lower, which makes it possible to reduce the electricity rate paid by the owners of water heaters 11. In other words, hot water supply system 100 capable of reducing the electricity rate paid by the owners of water heaters 11 is realized.

[0292] Invention 3 is hot water supply system 100 according to Invention 1 or 2, wherein when the plurality of water heaters 11 include two water heaters 11 for which the latest boiling start time is a same time, determiner 130 determines the schedule to start boiling in order from water heater 11, among the two water heaters 11, for which the boiling amount included in the hot water supply information for that water heater 11 is higher.

[0293] Through this, as described in Operation Example 1, the schedule is determined such that boiling by water heater 11 having a high boiling amount (e.g., third water heater 11c) is performed preferentially, which makes it less likely that water heater 11 will run out of hot water. In other words, hot water supply system 100 that makes it difficult for hot water heaters 11 to run out of hot water is realized.

[0294] Invention 4 is hot water supply system 100 according to Invention 2, wherein obtainer 120 obtains a first power unit price for the first time slot and a second power unit price for the second time slot, and based on the first power unit price and the second power unit price obtained, determiner 130 determines the schedule to reduce an electricity rate resulting from the boiling by each of the plurality of water heaters 11.

[0295] Through this, as described in Operation Example 2, the boiling by water heater 11 (e.g., first water heater 11a) is performed during a time slot in which the power unit price is lower, which makes it possible to reduce the electricity rate paid by the owner of water heater 11. In other words, hot water supply system 100 capable of reducing the electricity rate paid by the owners of water heaters 11 is realized.

[0296] Invention 5 is hot water supply system 100 according to Invention 4, wherein when a plurality of second time slots, each being the second time slot, are provided in one day, based on the first power unit price and the second power unit price obtained, and the usage start time included in each of the plurality of items of hot water supply information obtained, determiner 130 determines the schedule to reduce the electricity rate resulting from the boiling by each of the plurality of water heaters 11, and to shorten a time difference between a first expected completion time and the usage start time, the first expected completion time being a time at which the boiling by each of the plurality of water heaters 11 is expected to be completed.

[0297] Through this, as described in Operation Example 3, the boiling by water heater 11 (e.g., first water heater 11a) is performed during a time slot in which the power unit price is lower, which makes it possible to reduce the electricity rate paid by the owner of water heater 11. Incidentally, as indicated in (a) of FIG. 9, if the time from the first expected completion time to the usage start time is long, a problem arises in that the boiled water cools down. However, in Operation Example 3, as indicated in (b) of FIG. 9, the time difference between the first expected completion time and the usage start time is short, which makes it unlikely that the stated problem will arise. In other words, hot water supply system 100 that can reduce the electricity rate paid by the owners of water heaters 11, and that makes it less likely that a problem in which the boiled water cools down will occur, is realized.

[0298] Invention 6 is hot water supply system 100 according to any one of Inventions 1 to 5, wherein when controller 140 is controlling boiling by the plurality of water heaters 11 based on the schedule determined, when the overall demand power of the plurality of residences is determined to exceed the first reference power obtained, determiner 130 updates the schedule to stop boiling by water heater 11, among the plurality of water heaters 11, for which a time difference between a second expected completion time and a third expected completion time is greatest, the second expected completion time being a time at which boiling indicated by the schedule determined is expected to be completed, and the third expected completion time being a time at which boiling is expected to be completed when the boiling is started at the latest boiling start time; and controller 140 controls boiling by the plurality of water heaters 11 based on the schedule updated.

[0299] Through this, as described in Operation Example 4, the schedule is updated such that hot water supply system 100 stops the boiling by water heater 11 (second water heater 11b) when the demand power exceeds the first reference power. Accordingly, situations where the demand power exceeds the first reference power are suppressed. In other words, hot water supply system 100 capable of suppressing the overall demand power (and more specifically, the maximum value of the demand power) of a plurality of residences (housing complex 40, in Operation Example 4) is realized. Additionally, having determiner 130 update the schedule to stop the boiling by water heater 11 for which the time difference between the second expected completion time and the third expected completion time is large makes it less likely that water heater 11 for which the time difference is small and water heater 11 for which the time difference is large will run out of hot water.

[0300] Invention 7 is hot water supply system 100 according to any one of Inventions 1 to 6, wherein when controller 140 is causing two or more water heaters 11 among the plurality of water heaters 11 to boil according to the schedule determined, obtainer 120 obtains a boiling instruction instructing boiling by other water heater 11, among the plurality of water heaters 11, aside from the two or more water heaters 11; determiner 130 updates the schedule to start the boiling by other water heater 11 based on the boiling instruction obtained; and controller 140 controls boiling by the plurality of water heaters 11 based on the schedule updated.

[0301] Through this, as described in Operation Example 5, hot water supply system 100 performs the following processing when the boiling instruction for other water heater 11 (third water heater 11c) is obtained. That is, hot water supply system 100 updates the schedule to start the boiling by other water heater 11. Through this, hot water supply system 100 can perform the boiling by other water heater 11.

[0302] Invention 8 is hot water supply system 100 according to Invention 7, wherein when an information processing device accepts an operation from an owner of other water heater 11, the information processing device outputs the boiling instruction, the boiling instruction being indicated by the operation accepted, and obtainer 120 obtains the boiling instruction output.

[0303] Through this, as described in Operation Example 5, hot water supply system 100 can update the schedule in response to an operation made by the owner.

[0304] Invention 9 is hot water supply system 100 according to Invention 7 or 8, wherein based on the boiling instruction obtained, when the overall demand power of the plurality of residences is determined to exceed the first reference power obtained, determiner 130 updates the schedule to stop boiling by water heater 11, among the two or more water heaters 11, for which a time difference between a second expected completion time and a third expected completion time is greatest, and to start the boiling by other water heater 11, the second expected completion time being a time at which boiling indicated by the schedule determined is expected to be completed, and the third expected completion time being a time at which boiling is expected to be completed when boiling is started at the latest boiling start time.

[0305] Through this, as described in Operation Example 5, hot water supply system 100 performs the following processing when the demand power is determined to exceed the first reference power based on the boiling instruction for other water heater 11 (third water heater 11c). That is, hot water supply system 100 suppresses situations where the demand power exceeds the first reference power by updating the schedule to stop the boiling by water heater 11 (second water heater 11b). In other words, hot water supply system 100 capable of suppressing the overall demand power (and more specifically, the maximum value of the demand power) of a plurality of residences (housing complex 40, in Operation Example 5) is realized. Furthermore, determiner 130 updates the schedule to stop the boiling by water heater 11 for which the time difference between the second expected completion time and the third expected completion time is large (second water heater 11b). Through this, it becomes less likely that water heater 11 for which the time difference is small and water heater 11 for which the time difference is large will run out of hot water. In other words, hot water supply system 100 that makes it difficult to run out of hot water is realized.

[0306] Invention 10 is hot water supply system 100 according to Invention 2, wherein based on the usage start time included in each of the plurality of items of hot water supply information obtained, when, among the plurality of water heaters 11, a first target water heater for which a time from a second expected completion time to the usage start time exceeds a reference time is determined to be present, the second expected completion time being a time at which boiling indicated by the schedule determined is expected to be completed, determiner 130 re-determines the schedule to pause and then re-perform boiling by the first target water heater after the boiling by the first target water heater is performed in the second time slot, and complete the boiling by the first target water heater by the usage start time.

[0307] Through this, as described in Operation Example 6, the schedule is re-determined by determiner 130 to temporarily stop the boiling by the first target water heater after the boiling by the first target water heater, start the boiling again, and complete the boiling by the first target water heater by the usage start time. Note that determiner 130 re-determines the schedule such that the time from the time when the boiling by the first target water heater is completed to the expected usage time drops below the reference time due to the boiling being performed again. Accordingly, the time from the time when the boiling by the first target water heater is completed to the expected usage time is sufficiently shortened, and the problem that the boiled water cools down therefore becomes unlikely to occur. In other words, hot water supply system 100 that makes it difficult for the stated problem to occur is realized.

[0308] Invention 11 is hot water supply system 100 according to any one of Inventions 1 to 10, wherein when the plurality of water heaters 11 include a second target water heater for which a boiling number indicated by the schedule determined is at least a predetermined number, determiner 130 re-determines the schedule to bring the boiling number of the second target water heater to less than the predetermined number.

[0309] Through this, as described in Operation Example 7, the boiling number of the second target water heater is less than the predetermined number, and thus a problem that the amount of power consumed by water heater 11 increases due to the number of boiling times being high is unlikely to occur. In other words, the amount of consumed power is suppressed, and thus hot water supply system 100 can suppress the overall demand power (and more specifically, the maximum value of the demand power) of housing complex 40.

[0310] Invention 12 is hot water supply system 100 according to Invention 2, wherein when controller 140 is controlling boiling by the plurality of water heaters 11 in accordance with the schedule determined, obtainer 120 obtains a second reference power for the plurality of residences, the second reference power being a reference power lower than the first reference power and for a partial time slot included in the second time slot; when the overall demand power of the plurality of residences is determined to exceed the second reference power obtained in the partial time slot in the schedule determined, determiner 130 updates the schedule to start boiling in order from water heater 11, among the plurality of water heaters 11, for which the latest boiling start time is earliest; and controller 140 controls boiling by the plurality of water heaters 11 in the partial time slot based on the schedule updated.

[0311] Through this, as described in Operation Example 9, hot water supply system 100 capable of suppressing the overall demand power (and more specifically, the maximum value of the demand power) of a plurality of residences (housing complex 40, in Operation Example 9) is realized. For example, as indicated in (b) of FIG. 20, situations where the maximum value of the demand power exceeds the second reference power are suppressed. This makes it less likely that the base rate for housing complex 40 will rise.

[0312] Invention 13 is a hot water supply method executed by hot water supply system 100, the hot water supply method including: obtaining a plurality of items of hot water supply information, each including a boiling amount of water heater 11 and a usage start time of water heater 11, and a first reference power of a plurality of residences in which a plurality of water heaters 11 are respectively installed, each of the plurality of water heaters 11 being water heater 11; determining, based on the boiling amount included in each of the plurality of items of the hot water supply information obtained, a schedule for starting boiling in order from water heater 11, among the plurality of water heaters 11, for which a latest boiling start time is earliest, when starting boiling by the plurality of water heaters 11 simultaneously is determined to cause an overall demand power of the plurality of residences to exceed the first reference power obtained, the latest boiling start time being a latest time to start boiling to ensure hot water does not run out at the usage start time included in the hot water supply information for that water heater 11; and controlling boiling by the plurality of water heaters 11 based on the schedule determined.

[0313] Through this, as described in Operation Example 1, a hot water supply method capable of suppressing the overall demand power (and more specifically, the maximum value of the demand power) of a plurality of residences (housing complex 40, in Operation Example 1) is realized. For example, as indicated in (b) of FIG. 3, situations where the maximum value of the demand power exceeds the first reference power are suppressed. This makes it less likely that the base rate for housing complex 40 will rise.(Other Embodiments)

[0314] Although an embodiment has been described thus far, the present invention is not limited to the foregoing embodiment and variations.

[0315] Note that the first time slot was described as being from 7 AM to 11 PM, and the second time slot as being from 11 PM to 7 AM the next day, as an example, but the time slots are not limited thereto.

[0316] In addition, although the boiling amount was determined by control device 13, the configuration is not limited thereto. For example, hot water supply system 100 may calculate the boiling amount from the target boiling amount and the remaining hot water amount in the storage tank.

[0317] To determine the boiling amount and the usage start time, a period from the day before the one day back to one week prior thereto was used as the past predetermined period, but the configuration is not limited thereto. For example, a period of one week before and after the day one year previous to the stated day may be used as the predetermined period in the past.

[0318] Additionally, the method through which the devices communicate with each other described in the foregoing embodiment and variations is merely one example. The method through which the devices communicate with each other is not particularly limited.

[0319] In the foregoing embodiment and variations, the used power (consumed power) required for the boiling by water heater 11 was proportional to the boiling amount of that water heater 11, but the configuration is not limited thereto.

[0320] For example, hot water supply system 100 may calculate the used power required for the boiling by water heater 11 and the time required for the boiling based on the specifications (specs) of each of the plurality of water heaters 11, the region where the plurality of water heaters 11 are installed, the season at the present time, and the like. Hot water supply system 100 performs this calculation such that, for example, if the area where the plurality of water heaters 11 are installed is a colder region, the used power required for the boiling by water heater 11 is greater, and the time required for the boiling by water heater 11 is longer. In addition, hot water supply system 100 performs the calculation such that, if the current season is winter, the used power required for the boiling by water heater 11 is greater, and the time required for the boiling by water heater 11 is longer. Additionally, for example, if hot water supply system 100 cannot obtain information indicating the season at the present time, hot water supply system 100 may obtain data including the temperature and the water temperature at the present time (data from the Meteorological Agency or the like), and calculate the used power required for the boiling by water heater 11 and the time required for the boiling based on that data.

[0321] Additionally, for example, hot water supply system 100 may obtain data including historical temperatures and water temperatures (data from the Meteorological Agency or the like), and calculate the used power required for the boiling by water heater 11 and the time required for the boiling based on that data.

[0322] Additionally, if the overall demand power of the plurality of residences is determined to exceed the first reference power, the following processing may be performed. For example, communicator 110 of hot water supply system 100 according to the embodiment sends information (a message) requesting cooperation with power conservation to control device 13 of each of the plurality of individual dwellings 10 or the information terminals (e.g., smartphones) owned by the owners. The owners of individual dwellings 10 can therefore be expected to cooperate with power conservation. A display of hot water supply system 100 displays the difference in the rates (the amount by which the rate is reduced) when the demand power does not exceed the first reference power compared to when the demand power exceeds the first reference power. The manager of hot water supply system 100 can make the owners who cooperate with power conservation more amenable to such cooperation by paying the displayed rate reduction to those owners.

[0323] Note that it is preferable to notify the owner of the reduction in the stated rate before the information (message) requesting cooperation with power conservation is sent. For example, information indicating the stated reduction in the rate may be output from communicator 110 of hot water supply system 100 to control device 13 of each of the plurality of individual dwellings 10 or the information terminals (e.g., smartphones) owned by the owners. This enables the owners to see the financial benefits of cooperating with power conservation.

[0324] In addition, there are cases where it is clear in advance (e.g., one hour or one week in advance) that the overall demand power of the plurality of residences will exceed the first reference power in a given time slot.

[0325] As an example, in this case, it is preferable to send the information (message) requesting cooperation with power conservation before the given time slot (e.g., the day before or several hours before the given time slot). This gives the owner time to consider whether to cooperate with power conservation before the start of the given time slot.

[0326] As another example, in this case, the power unit price for the given time slot may be raised. In other words, a higher power unit price is used than the power unit price used when the overall demand power of the plurality of residences does not exceed the first reference power in the given time slot. Hot water supply system 100 performs the processing of the foregoing operation examples using the power unit price raised in this manner.

[0327] In addition, the manager of hot water supply system 100 may obtain information on cooperation with power conservation by a plurality of owners by conducting a questionnaire on such cooperation with the owners of first to fifth individual dwellings 10a to 10e. By controlling an information terminal such as a smartphone, a tablet, or a personal computer, the manager sends information about the cooperation with power conservation to communicator 110 of hot water supply system 100. Obtainer 120 of hot water supply system 100 obtains a plurality of items of information on cooperation with power conservation, obtained by communicator 110. The questionnaire asks whether the owner can cooperate with power conservation in individual dwelling 10 they own when the overall demand power of the plurality of residences exceeds the first reference power obtained, and the results of the questionnaire are reflected in the information on the cooperation with power conservation. Based on the plurality of items of information about cooperation with power conservation obtained, hot water supply system 100 determines equipment (water heaters 11 and electrical equipment 21) to stop when the overall demand power of the plurality of residences exceeds the first reference power obtained. Hot water supply system 100 determines a schedule to stop the determined equipment, and controls the equipment based on the schedule determined. For example, if the information on cooperation with power conservation indicates that such cooperation is not possible in all of first to fifth individual dwellings 10a to 10e, hot water supply system 100 determines a schedule to stop electrical equipment 21 installed in common area 20.

[0328] Processing executed by a specific processor in the foregoing embodiment and variations may be executed by a different processor. Additionally, the order of multiple processes may be changed, and multiple processes may be executed in parallel.

[0329] Additionally, in the foregoing embodiment and variation, the constituent elements such as obtainer 120, determiner 130, controller 140, and the like may be implemented by executing software programs corresponding to those constituent elements. Each constituent element may be realized by a program executor such as a CPU or a processor reading out and executing a software program recorded into a recording medium such as a hard disk or semiconductor memory.

[0330] Constituent elements such as obtainer 120, determiner 130, controller 140, and the like may be implemented by hardware. For example, constituent elements such as controller 140 may be circuitry (or integrated circuitry). This circuitry may constitute a single overall circuit, or may be separate circuits. The circuitry may be generic circuitry, or may be dedicated circuitry.

[0331] The general or specific aspects of the present invention may be implemented by a system, a device, a method, an integrated circuit, a computer program, or a computer-readable recording medium such as a CD-ROM. These forms may also be implemented by any desired combination of systems, devices, methods, integrated circuits, computer programs, and recording media. For example, the present invention may be realized as hot water supply system 100 according to the foregoing embodiment and variations, or as a hot water supply method executed by hot water supply system 100. The present invention may be implemented as a program for causing a computer to execute such a hot water supply method, or as a non-transitory recording medium having such a program recorded thereon. Such a program includes an application program for causing a computer, such as a general-purpose information terminal or the like, to function as hot water supply system 100 according to the foregoing embodiment and variations.

[0332] Note that embodiments resulting from variations on the above embodiment and variations arrived at by those skilled in the art, as well as embodiments resulting from optional combinations of elements and functions in the above embodiment and variations are included within the present invention as long as the embodiments do not depart from the scope of the present invention.[Reference Signs List]

[0333] 11, 411 Water heater 100 Hot water supply system 120 Obtainer 130 Determiner 140 Controller

Examples

embodiment

[Embodiment]

[Configuration]

[0014]The configuration of hot water supply system 100 according to the present embodiment will be described.

[0015]FIG. 1A is a block diagram illustrating the functional configuration of hot water supply system 100 according to the present embodiment.

[0016]Hot water supply system 100 is a system installed in housing complex 40. Accordingly, FIG. 1A is a block diagram also illustrating functional configurations of housing complex 40 aside from hot water supply system 100. Hot water supply system 100 suppresses a maximum value of the overall demand power of housing complex 40 by controlling a plurality of water heaters 11 installed in a plurality of residences included in housing complex 40.

[0017]In housing complex 40 according to the present embodiment, a high-voltage collective power reception contract is selected as the type of contract for supplying power to housing complex 40. In this contract, two types of time slots having different power unit prices ...

example 1

[Operation Example 1]

[0051]FIG. 2 is a flowchart of Operation Example 1 according to the present embodiment.

[0052]As illustrated in FIG. 2, steps S10, S20, S30, and S40 are processing performed in the first time slot, and step S90 is processing performed in the second time slot. Note that the time slot in which a step is performed may be indicated in the flowcharts in subsequent figures as well.

[0053]Although the present operation example describes an example in which the schedule is determined in the first time slot and the boiling by the plurality of water heaters 11 is performed in the second time slot, the configuration is not limited thereto. As described above, hot water supply system 100 may determine a schedule for boiling by the plurality of water heaters 11 before the boiling by the plurality of water heaters 11 starts, and control the boiling by the plurality of water heaters 11 based on the schedule determined. Accordingly, for example, the schedule may be determined in ...

example 2

[Operation Example 2]

[0095]FIG. 6 is a flowchart of Operation Example 2 according to the present embodiment. FIG. 7 is a diagram illustrating a schedule of Operation Example 2 according to the present embodiment.

[0096]Operation Example 2 will describe an example in which three types of time slots having different power unit prices (first to third time slots) are provided, and a schedule for boiling by one water heater 11 (here, first water heater 11a) is determined.

[0097]As illustrated in FIG. 6, the processing of step S10 is performed first, in the same manner as in FIG. 2.

[0098] Then, obtainer 120 obtains the first power unit price for the first time slot and the second power unit price for the second time slot. More specifically, obtainer 120 obtains the first power unit price for the first time slot, the second power unit price for the second time slot, and the third power unit price for the third time slot (S11). Obtainer 120 obtains the first power unit price, the second power...

[Technical Field]

[0001] The present invention relates to a hot water supply system and a hot water supply method.[Background Art]

[0002] Patent Literature (PTL) 1 discloses a storage-type water heater. Such a storage-type water heater generally stores hot water boiled during a time slot when the power unit price is low in a storage tank, and then supplies that hot water as necessary. The power unit price is low in nighttime time slots, for example.[Citation List][Patent Literature]

[0003] [PTL 1] Japanese Unexamined Patent Application Publication No. 2012-225601[Summary of Invention][Technical Problem]

[0004] A plurality of the water heaters disclosed in PTL 1 may be installed in a housing complex including a plurality of residences, for example. In such a case, if the water heaters start boiling simultaneously during a nighttime time slot, the overall demand power of the housing complex at that time may become extremely high.

[0005] Incidentally, the types of contracts for supplying power to a housing complex include a high-voltage collective power reception contract. In such a contract, the management company or management association of the housing complex enters into a contract with the power company, and a user in each household then enters into a contract with the manager or management association of the housing complex. In a high-voltage collective power reception contract, a reference power, which is a reference value (an upper limit value) for the overall demand power of the housing complex, is set. If the reference power is exceeded, a contract in which the reference power is increased and the base rate is raised will be required for the current month and the 11 months from the following month.

[0006] Accordingly, if the overall demand power of a housing complex including a plurality of residences becomes extremely high due to boiling by a plurality of water heaters as described above, the demand power (and more specifically, a maximum value of the demand power) may exceed the reference power and cause the base rate to rise as a result. Problems such as breakers tripping also occur when the demand power increases.

[0007] The present invention provides a hot water supply system and the like capable of suppressing the maximum value of the overall demand power of a plurality of residences.[Solution to Problem]

[0008] A hot water supply system according to one aspect of the present invention includes: an obtainer that obtains a plurality of items of hot water supply information, each including a boiling amount of a water heater and a usage start time of the water heater, and a first reference power of a plurality of residences in which a plurality of water heaters are respectively installed, each of the plurality of water heaters being the water heater; a determiner that, based on the boiling amount included in each of the plurality of items of the hot water supply information obtained, determines a schedule for starting boiling in order from a water heater, among the plurality of water heaters, for which a latest boiling start time is earliest, when starting boiling by the plurality of water heaters simultaneously is determined to cause an overall demand power of the plurality of residences to exceed the first reference power obtained, the latest boiling start time being a latest time to start boiling to ensure hot water does not run out at the usage start time included in the hot water supply information for that water heater; and a controller that controls boiling by the plurality of water heaters based on the schedule determined.

[0009] A hot water supply method according to one aspect of the present invention is a hot water supply method executed by a hot water supply system, the hot water supply method including: obtaining a plurality of items of hot water supply information, each including a boiling amount of a water heater and a usage start time of the water heater, and a first reference power of a plurality of residences in which a plurality of water heaters are respectively installed, each of the plurality of water heaters being the water heater; determining, based on the boiling amount included in each of the plurality of items of the hot water supply information obtained, a schedule for starting boiling in order from a water heater, among the plurality of water heaters, for which a latest boiling start time is earliest, when starting boiling by the plurality of water heaters simultaneously is determined to cause an overall demand power of the plurality of residences to exceed the first reference power obtained, the latest boiling start time being a latest time to start boiling to ensure hot water does not run out at the usage start time included in the hot water supply information for that water heater; and controlling boiling by the plurality of water heaters based on the schedule determined.[Advantageous Effects of Invention]

[0010] The hot water supply system and the like of the present invention make it possible to suppress the maximum value of the overall demand power of a plurality of residences.[Brief Description of Drawings]

[0011] [FIG. 1A] FIG. 1A is a block diagram illustrating the functional configuration of a hot water supply system according to an embodiment. [FIG. 1B] FIG. 1B is a diagram illustrating an example of a power unit price according to the embodiment. [FIG. 2] FIG. 2 is a flowchart of Operation Example 1 according to the embodiment. [FIG. 3] FIG. 3 is a diagram illustrating a schedule of Operation Example 1 according to the embodiment. [FIG. 4] FIG. 4 is a more detailed flowchart illustrating step S30 of Operation Example 1 according to the embodiment. [FIG. 5] FIG. 5 is another diagram illustrating a schedule of Operation Example 1 according to the embodiment. [FIG. 6] FIG. 6 is a flowchart of Operation Example 2 according to the embodiment. [FIG. 7] FIG. 7 is a diagram illustrating a schedule of Operation Example 2 according to the embodiment. [FIG. 8] FIG. 8 is a flowchart of Operation Example 3 according to the embodiment. [FIG. 9] FIG. 9 is a diagram illustrating a schedule of Operation Example 3 according to the embodiment. [FIG. 10] FIG. 10 is a flowchart of Operation Example 4 according to the embodiment. [FIG. 11] FIG. 11 is a diagram illustrating a schedule of Operation Example 4 according to the embodiment. [FIG. 12] FIG. 12 is a flowchart of Operation Example 5 according to the embodiment. [FIG. 13] FIG. 13 is a diagram illustrating a schedule of Operation Example 5 according to the embodiment. [FIG. 14] FIG. 14 is a flowchart of Operation Example 6 according to the embodiment. [FIG. 15] FIG. 15 is a diagram illustrating a schedule of Operation Example 6 according to the embodiment. [FIG. 16] FIG. 16 is a flowchart of Operation Example 7 according to the embodiment. [FIG. 17] FIG. 17 is a flowchart of Operation Example 8 according to the embodiment. [FIG. 18] FIG. 18 is a diagram illustrating a schedule and an electricity rate of Operation Example 8 according to the embodiment. [FIG. 19] FIG. 19 is a flowchart of Operation Example 9 according to the embodiment. [FIG. 20] FIG. 20 is a diagram illustrating a schedule of Operation Example 9 according to the embodiment. [FIG. 21] FIG. 21 is a flowchart of Operation Example 10 according to the embodiment. [FIG. 22] FIG. 22 is a flowchart of Operation Example 11 according to the embodiment. [FIG. 23] FIG. 23 is a flowchart of Operation Example 12 according to the embodiment. [FIG. 24] FIG. 24 is a block diagram illustrating the functional configuration of a hot water supply system according to Variation 1 on the embodiment. [FIG. 25] FIG. 25 is a block diagram illustrating the functional configuration of a hot water supply system according to Variation 2 on the embodiment. [FIG. 26] FIG. 26 is a block diagram illustrating the functional configuration of a hot water supply system according to Variation 3 on the embodiment. [Description of Embodiment]

[0012] An embodiment will be described in detail hereinafter with reference to the drawings. The following embodiment will describe general or specific examples. The numerical values, shapes, materials, constituent elements, arrangements and connection states of constituent elements, steps, orders of steps, and the like in the following embodiment are merely examples, and are not intended to limit the present invention. Additionally, of the constituent elements in the following embodiment, constituent elements not denoted in the independent claims will be described as optional constituent elements.

[0013] Note also that the drawings are schematic diagrams, and are not necessarily exact illustrations. Configurations that are substantially the same are given the same reference signs in the drawings, and redundant descriptions may be omitted or simplified.[Embodiment][Configuration]

[0014] The configuration of hot water supply system 100 according to the present embodiment will be described.

[0015] FIG. 1A is a block diagram illustrating the functional configuration of hot water supply system 100 according to the present embodiment.

[0016] Hot water supply system 100 is a system installed in housing complex 40. Accordingly, FIG. 1A is a block diagram also illustrating functional configurations of housing complex 40 aside from hot water supply system 100. Hot water supply system 100 suppresses a maximum value of the overall demand power of housing complex 40 by controlling a plurality of water heaters 11 installed in a plurality of residences included in housing complex 40.

[0017] In housing complex 40 according to the present embodiment, a high-voltage collective power reception contract is selected as the type of contract for supplying power to housing complex 40. In this contract, two types of time slots having different power unit prices are provided, the two types of time slots being, for example, a first time slot and a second time slot in which the power unit price is lower than in the first time slot. Note, however, that in the contract, three types of time slots having different power unit prices may be provided, the three types of time slots being, for example, a first time slot, a second time slot in which the power unit price is lower than in the first time slot, and a third time slot in which the power unit price is higher than in the first time slot. In the contract, four or more types of time slots having different power unit prices may be provided.

[0018] The power unit price and time slots will be described further with reference to FIG. 1B.

[0019] FIG. 1B is a diagram illustrating an example of the power unit price according to the present embodiment. More specifically, (a) of FIG. 1B is a diagram illustrating an example in which two types of time slots having different power unit prices are provided for a single day, and (b) of FIG. 1B is a diagram illustrating an example in which the power unit price changes each predetermined time period (e.g., 30 minutes) in a single day. In the present embodiment, as described above, two types of time slots may be provided, three or more types of time slots may be provided, and the power unit price may fluctuate every predetermined time period (e.g., 30 minutes) as indicated in (b) of FIG. 1B. Hereinafter, unless otherwise stated, the present embodiment will be described assuming that two types of time slots having different power unit prices are provided.

[0020] For example, the first time slot is a time slot other than at night, and the second time slot is a time slot at night. Unless otherwise stated, the first time slot in which the power unit price is higher is from 7 AM to 11 PM, the second time slot in which the power unit price is lower is from 11 PM to 7 AM the next day, and the first time slot and the second time slot are consecutive time slots. In general, hot water stored in water heater 11 has a higher usage amount and usage frequency in the first time slot other than at night, and a low usage amount and usage frequency in the second time slot at night.

[0021] Hot water supply system 100 according to the present embodiment determines a schedule for boiling by the plurality of water heaters 11 before boiling by the plurality of water heaters 11 starts, and controls the plurality of water heaters 11 based on the schedule determined. For example, hot water supply system 100 determines a schedule for boiling by the plurality of water heaters 11 before the start of the second time slot, i.e., during the first time slot, and controls the plurality of water heaters 11 based on the schedule determined.

[0022] Housing complex 40 is a facility including a plurality of households (i.e., a plurality of residences) and common area 20, and is, for example, an apartment building or the like.

[0023] The number of households in housing complex 40 is, for example, in the teens, 20 to 100, or hundreds, but is not limited thereto. Here, each of the plurality of households is individual dwelling 10 (i.e., a residence) of a resident, and may be referred to as first individual dwelling 10a, second individual dwelling 10b, third individual dwelling 10c, fourth individual dwelling 10d, and fifth individual dwelling 10e for identification. The plurality of households also include a plurality of other individual dwellings 10 in addition to first to fifth individual dwellings 10a to 10e. When there is no particular need for identification, first to fifth individual dwellings 10a to 10e may simply be referred to as individual dwellings 10.

[0024] Each of the plurality of households includes water heater 11, electrical equipment 12, and control device 13. In other words, each of the plurality of water heaters 11 installed in a plurality of residences is a water heater provided for a corresponding one of the plurality of households, and more specifically, is a storage-type water heater. For identification, water heaters 11 provided in first to fifth individual dwellings 10a to 10e will be referred to as first to fifth water heaters 11a to 11e. In other words, the plurality of water heaters 11 include first to fifth water heaters 11a to 11e. When there is no particular need for identification, first to fifth water heaters 11a to 11e may simply be referred to as "water heaters 11". Each of the plurality of water heaters 11 communicates with a respective one of a plurality of control devices 13.

[0025] Electrical equipment 12 and control device 13 have the same functions throughout the plurality of households, and thus electrical equipment 12 and control device 13 provided in first individual dwelling 10a will be described here as an example.

[0026] "Electrical equipment 12" refers to all electrical equipment in first individual dwelling 10a aside from first water heater 11a. For example, electrical equipment 12 includes household appliances such as lighting fixtures, air conditioners, and the like in first individual dwelling 10a.

[0027] Control device 13 is a device for communicating with and controlling first water heater 11a and electrical equipment 12 in first individual dwelling 10a. More specifically, control device 13 is what is known as a Home Energy Management System (HEMS) controller that monitors or controls the operating states of first water heater 11a and electrical equipment 12 by communicating with first water heater 11a and electrical equipment 12. For example, through this communication, control device 13 obtains, from first water heater 11a, the remaining hot water amount in a storage tank of first water heater 11a (also called a "stored hot water amount"). Control device 13 also communicates with hot water supply system 100.

[0028] Control device 13 includes an acceptor that accepts operations from an owner (i.e., a resident) of first individual dwelling 10a. Specifically, the acceptor is realized by a touch panel or the like. This acceptor accepts, from the owner of first individual dwelling 10a, an operation instructing a target boiling amount for first water heater 11a, for example.

[0029] The target boiling amount is a target amount for the remaining hot water amount in the storage tank (stored hot water amount) of first water heater 11a when boiling by first water heater 11a is completed by hot water supply system 100. The target boiling amount may also be a hot water amount expected to be used by the owner of first individual dwelling 10a. It should be noted that control device 13 may determine a value obtained by subtracting (i) the remaining hot water amount in the storage tank of first water heater 11a (more specifically, the stored hot water amount from before the boiling) obtained from (ii) the target boiling amount indicated by the accepted instruction as the boiling amount of first water heater 11a.

[0030] The acceptor of control device 13 accepts, from the owner of first individual dwelling 10a, an operation instructing a usage start time, which is a time at which the use of hot water stored in first water heater 11a starts.

[0031] Control device 13 outputs hot water supply information about first water heater 11a to hot water supply system 100. The hot water supply information for first water heater 11a is information including a determined boiling amount (i.e., the boiling amount of first water heater 11a) and a usage start time indicated by an instruction accepted by the acceptor of control device 13 (i.e., a usage start time of first water heater 11a).

[0032] In addition, control device 13 outputs, to hot water supply system 100, individual dwelling power information about the power used by electrical equipment 12.

[0033] The individual dwelling power information includes information indicating an expected used power based on an expected usage amount for electrical equipment 12. The information indicating the expected used power is information based on an expected usage amount for electrical equipment 12, the expected usage amount being for a predetermined time slot (e.g., the second time slot) on a given day. For example, at 10 PM, which corresponds to the first time slot on that day, control device 13 predicts and determines the expected used power for the second time slot starting at 11 PM on that day, based on the past used power amount for electrical equipment 12 on that day. In this case, as the expected used power for electrical equipment 12 for that day, control device 13 determines an average value of the power used by electrical equipment 12 in the second time slot over a past predetermined period (e.g., a period of one week in the past from the previous day). The individual dwelling power information also includes information indicating the power used by electrical equipment 12 at the present time in a predetermined time slot (e.g., the second time slot) on a given day. Control device 13 outputs such individual dwelling power information to hot water supply system 100. Note that the predetermined time slot on a given day described above is not limited to the second time slot, and may be the first time slot.

[0034] Common area 20 in housing complex 40 is, for example, an area other than the plurality of households (residences) in housing complex 40, and is a common space such as hallways, the roof, gardens, staircases, and the like, for example.

[0035] Electrical equipment 21 and power measurement device 22 are installed in common area 20. Lighting, elevators, water pumps, and the like, for example, fall under electrical equipment 21. Power measurement device 22 measures the power used by electrical equipment 21 and outputs the measured power used to hot water supply system 100.

[0036] Furthermore, power measurement device 22 outputs, to hot water supply system 100, common area power information about the power used by electrical equipment 21. The common area power information includes information indicating an expected used power based on an expected usage amount for electrical equipment 21. The information indicating the expected used power is information based on an expected usage amount for electrical equipment 21, the expected usage amount being for a predetermined time slot (e.g., the second time slot) on a given day. For example, at 10 PM, which corresponds to the first time slot on that day, power measurement device 22 predicts and determines the expected used power for the second time slot starting at 11 PM on that day, based on the past used power amount for electrical equipment 21 on that day. In this case, as the expected used power for electrical equipment 21 for that day, power measurement device 22 determines an average value of the power used by electrical equipment 21 in the second time slot over a past predetermined period (e.g., a period of one week in the past from the previous day). The common area power information also includes information indicating the power used by electrical equipment 21 at the present time in a predetermined time slot (e.g., the second time slot) on a given day. Control device 13 outputs such common area power information to hot water supply system 100. Note that the predetermined time slot on a given day described above is not limited to the second time slot, and may be the first time slot.

[0037] Power supply equipment 23 is also installed in common area 20. Solar power generation equipment, charging equipment, and the like, for example, fall under power supply equipment 23. In other words, in the present embodiment, housing complex 40 includes power supply equipment 23, and power supply equipment 23 includes solar power generation equipment and charging equipment (e.g., storage batteries and electric automobiles).

[0038] The power output from power supply equipment 23 is supplied to a plurality of households (the plurality of water heaters 11, for example).

[0039] Note that power supply equipment 23 outputs power supply equipment information indicating a power generation amount, a charging amount, and the like by power supply equipment 23 to power measurement device 22, and power measurement device 22 outputs the obtained power supply equipment information to hot water supply system 100.

[0040] The constituent elements of hot water supply system 100 will be described here.

[0041] As illustrated in FIG. 1A, hot water supply system 100 includes communicator 110, obtainer 120, determiner 130, controller 140, and storage 150. Hot water supply system 100 is, for example, a personal computer, but may also be a server device or the like.

[0042] Communicator 110 is communication circuitry for hot water supply system 100 to communicate with control device 13 provided in each of the plurality of households and power measurement device 22 of common area 20. In the present embodiment, communicator 110 is circuitry for wireless communication, and communicator 110 communicates wirelessly according to various communication standards. Note that communicator 110 may be circuitry for communicating over wires.

[0043] Communicator 110 obtains the hot water supply information for each of the plurality of water heaters 11 from control device 13 of corresponding ones of the plurality of households. In other words, for example, communicator 110 obtains hot water supply information of first water heater 11a from control device 13 of first individual dwelling 10a, and obtains hot water supply information of second water heater 11b from control device 13 of second individual dwelling 10b.

[0044] Obtainer 120 is a processor that obtains a plurality of items of the hot water supply information and a first reference power. More specifically, obtainer 120 obtains the hot water supply information for each of the plurality of water heaters 11 obtained by communicator 110, and obtains the first reference power stored in storage 150. Note that this first reference power is a reference power for a plurality of residences in which a plurality of water heaters 11 are installed (here, housing complex 40), and is, for example, a reference power for the second time slot. The first reference power for the second time slot is a reference power specified in a high-voltage collective power reception contract, and is a first reference power for housing complex 40 in which the plurality of water heaters 11 are installed. When the overall demand power of housing complex 40 exceeds the first reference power, a contract in which the first reference power has been raised and the base rate is higher is required for the current month and the 11 months from the following month.

[0045] Determiner 130 determines a schedule based on the plurality of items of hot water supply information obtained by obtainer 120 and the first reference power obtained by obtainer 120. The schedule indicates a planned start time and a planned end time for the boiling by each of the plurality of water heaters 11. The schedule is, for example, a schedule for the boiling by each of the plurality of water heaters 11 in the second time slot. However, the schedule is not limited thereto, and may be, for example, a schedule for the boiling by each of the plurality of water heaters 11 in the first, second, and third time slots. The schedule further indicates a supply source that supplies power required for the boiling by each of the plurality of water heaters 11. Examples of the supply source include a power company, power supply equipment 23, and the like.

[0046] Controller 140 is a processor that controls the boiling by the plurality of water heaters 11 based on the schedule determined by determiner 130. Here, controller 140 causes communicator 110 to output, to each of the plurality of control devices 13, a control signal instructing the plurality of water heaters 11 to boil as indicated by the determined schedule.

[0047] As a result, each of the plurality of control devices 13 controls the corresponding one of the plurality of water heaters 11 according to the control signal output from communicator 110.

[0048] Each of obtainer 120, determiner 130, and controller 140 is realized by a microcomputer, for example, but may be realized by a processor or dedicated circuitry. The respective functions of obtainer 120, determiner 130, and controller 140 are realized by hardware such as microcomputers constituting obtainer 120, determiner 130, and controller 140, respectively, executing software stored in storage 150.

[0049] Storage 150 is a storage device that stores information necessary for information processing for controlling the plurality of water heaters 11, such as software executed by obtainer 120, determiner 130, and controller 140. Storage 150 is realized by semiconductor memory or the like, for example.

[0050] Operations performed in hot water supply system 100 according to the present embodiment having the foregoing configuration will be described next.[Operation Example 1]

[0051] FIG. 2 is a flowchart of Operation Example 1 according to the present embodiment.

[0052] As illustrated in FIG. 2, steps S10, S20, S30, and S40 are processing performed in the first time slot, and step S90 is processing performed in the second time slot. Note that the time slot in which a step is performed may be indicated in the flowcharts in subsequent figures as well.

[0053] Although the present operation example describes an example in which the schedule is determined in the first time slot and the boiling by the plurality of water heaters 11 is performed in the second time slot, the configuration is not limited thereto. As described above, hot water supply system 100 may determine a schedule for boiling by the plurality of water heaters 11 before the boiling by the plurality of water heaters 11 starts, and control the boiling by the plurality of water heaters 11 based on the schedule determined. Accordingly, for example, the schedule may be determined in the second time slot, and the boiling by the plurality of water heaters 11 may be performed in the first time slot. In the example illustrated in (b) of FIG. 1B, for example, the schedule may be determined by the start of a predetermined time slot (e.g., 12 PM to 2 PM), and the boiling by the plurality of water heaters 11 may be performed in the predetermined time slot.

[0054] First, obtainer 120 obtains a plurality of items of hot water supply information, each including a boiling amount and a usage start time, and a first reference power (S10). Here, obtainer 120 obtains the first reference power for the second time slot. Obtainer 120 obtains the plurality of items of hot water supply information obtained by communicator 110, and obtains the first reference power stored in storage 150. Before this step S10 is performed, each of the plurality of control devices 13 outputs the hot water supply information about the corresponding water heater 11 to hot water supply system 100 as described above.

[0055] In step S10, obtainer 120 may obtain the target boiling amount and the remaining hot water amount in the storage tank for each of the plurality of water heaters 11, obtained by communicator 110.

[0056] Note that step S10 corresponds to a step of obtaining.

[0057] In Operation Example 1, in the process of step S10, obtainer 120 obtains the individual dwelling power information about the power used by electrical equipment 12, and the common area power information about the power used by electrical equipment 21. More specifically, communicator 110 obtains the individual dwelling power information from each of the plurality of control devices 13 and the common area power information from power measurement device 22, and obtainer 120 obtains the individual dwelling power information and the common area power information obtained by communicator 110.

[0058] Accordingly, obtainer 120 obtains information indicating the expected used power based on the expected usage amount, in the second time slot, for electrical equipment 12 included in the individual dwelling power information. Likewise, obtainer 120 obtains information indicating the expected used power based on the expected usage amount, in the second time slot, for electrical equipment 21 included in the common area power information. In the present embodiment, all of the plurality of electrical equipment 12 in the plurality of households and electrical equipment 21 in common area 20 constitute electrical equipment aside from the plurality of water heaters 11 in housing complex 40. Accordingly, it can also be said that obtainer 120 obtains a second used power based on the expected usage amount, in the second time slot, by the electrical equipment aside from the plurality of water heaters 11 in housing complex 40.

[0059] Note that the "second used power" is information that integrates the expected used power, in the second time slot, for electrical equipment 12 indicated by the individual dwelling power information, and the expected used power, in the second time slot, for electrical equipment 21 indicated by the common area power information.

[0060] In this manner, in Operation Example 1, in the process of step S10, obtainer 120 obtains the second used power, which corresponds to the expected power amount in the second time slot for the electrical equipment aside from the plurality of water heaters 11 in housing complex 40.

[0061] Based on the boiling amounts included in the plurality of items of hot water supply information obtained by obtainer 120, determiner 130 determines whether the overall demand power of housing complex 40 will exceed the first reference power obtained if the plurality of water heaters 11 start boiling simultaneously (S20). Here, determiner 130 determines whether the overall demand power of housing complex 40 will exceed the first reference power obtained if the plurality of water heaters 11 start boiling simultaneously in the second time slot. More specifically, determiner 130 makes this determination based on the boiling amounts included in the plurality of items of hot water supply information and the second used power obtained (an expected power amount in the second time slot).

[0062] Subsequently, if determiner 130 determines that the demand power will exceed the first reference power (Yes in S20), determiner 130 determines the following schedule prior to the second time slot, i.e., the first time slot, in this instance. Determiner 130 determines a schedule that starts boiling in order from water heater 11, among the plurality of water heaters 11, for which a latest boiling start time is earliest (S30). The "latest boiling start time" is the latest time to start boiling so that hot water will not run out at the usage start time included in the hot water supply information for that water heater 11. For example, in first water heater 11a, if the usage start time is 6 AM and the time required for boiling is 3 hours, the latest boiling start time of first water heater 11a is 3 AM. If, in this case, the boiling start time of first water heater 11a is determined to be 5:50 AM or the like, it is likely that the remaining hot water amount will be insufficient at 6 AM, which is the usage start time, and that the hot water will run out (no hot water will remain).

[0063] Step S20 and step S30 will be described in more detail with reference to FIG. 3.

[0064] FIG. 3 is a diagram illustrating a schedule of Operation Example 1 according to the present embodiment. More specifically, (a) of FIG. 3 is a diagram illustrating the schedule when the plurality of water heaters 11 (first to third water heaters 11a to 11c) start boiling simultaneously, and (b) of FIG. 3 is a diagram illustrating the schedule when the start of boiling by third water heater 11c is delayed.

[0065] In FIG. 3, the period from t0 to t1, which indicate times, corresponds to the second time slot, and the period from t1 on corresponds to the first time slot. In step S20, determiner 130 determines whether the demand power will exceed the first reference power if the plurality of water heaters 11 start boiling at t0, which is the time at which the second time slot starts. The "demand power" is the sum of all the power used by the plurality of water heaters 11, the plurality of electrical equipment 12, and electrical equipment 21 in housing complex 40. The power used (consumed power) for the boiling by water heater 11 is proportional to the boiling amount by that water heater 11. As the boiling amount decreases, the time required for boiling by water heater 11 decreases as well.

[0066] In the schedule illustrated in (a) of FIG. 3, the demand power is higher than the first reference power, and determiner 130 therefore determines that the demand power will exceed the first reference power.

[0067] In addition, in the schedule illustrated in FIG. 3, the latest boiling start time of first water heater 11a is t11, the latest boiling start time of second water heater 11b is t12, and the latest boiling start time of third water heater 11c is t13. t11 is a time earlier than t12 and t13, and t12 is a time earlier than t13.

[0068] In such a case, determiner 130 determines a schedule to expedite the start of boiling by first and second water heaters 11a and 11b, which have an earlier latest boiling start time than third water heater 11c among first to third water heaters 11a to 11c (the schedule indicated by (b) of FIG. 3). In other words, determiner 130 determines a schedule that delays the start of boiling by third water heater 11c for which the latest boiling start time is the latest among first to third water heaters 11a to 11c. At this time, determiner 130 determines the schedule such that the demand power does not exceed the first reference power in the second time slot.

[0069] In (b) of FIG. 3, the boiling by first and second water heaters 11a and 11b begins simultaneously at time t0, at which the second time slot begins. However, the configuration is not limited thereto. A case will be described in which the demand power will exceed the first reference power if the boiling by first and second water heaters 11a and 11b starts simultaneously. In this case, determiner 130 determines a schedule that expedites the start of boiling by first water heater 11a, which has an earlier latest boiling start time than second water heater 11b among first and second water heaters 11a and 11b.

[0070] In this manner, determiner 130 determines a schedule that starts boiling in order from water heater 11 for which the latest boiling start time is the earliest.

[0071] Note that step S20 and step S30 correspond to a step of determining.

[0072] However, if determiner 130 determines that the demand power will not exceed the first reference power (No in S20), determiner 130 determines the following schedule prior to the second time slot, i.e., the first time slot, in this instance. Determiner 130 determines a schedule that starts the boiling by the plurality of water heaters 11 simultaneously (step S40).

[0073] Furthermore, controller 140 controls the boiling by the plurality of water heaters 11 based on the schedule determined by determiner 130 in step S30 or S40 (S90). Here, controller 140 controls boiling by the plurality of water heaters 11 in the second time slot based on the schedule determined. More specifically, controller 140 controls communicator 110 to output, to each of the plurality of control devices 13, a control signal instructing the plurality of water heaters 11 to boil as indicated by the determined schedule. As a result, each of the plurality of control devices 13 controls a corresponding one of the plurality of water heaters 11 based on control signals obtained from communicator 110. For example, control device 13 of first individual dwelling 10a causes first water heater 11a to boil using time t0 indicated in (b) of FIG. 3 as a boiling start time of first water heater 11a. Additionally, for example, control device 13 of second individual dwelling 10b causes second water heater 11b to boil using time t0 indicated in (b) of FIG. 3 as the boiling start time of second water heater 11b. Additionally, for example, control device 13 of third individual dwelling 10c causes third water heater 11c to boil using time t13 indicated in (b) of FIG. 3 as the boiling start time of third water heater 11c. Note that step S90 corresponds to a step of controlling.

[0074] In this manner, if determiner 130 determines that the demand power will exceed the first reference power in the first time slot (Yes in S20), determiner 130 determines the following schedule. Determiner 130 determines a schedule that starts boiling in order from water heater 11 for which the latest boiling start time is the earliest among the plurality of water heaters 11.

[0075] Through this, in Operation Example 1, hot water supply system 100 capable of suppressing the overall demand power (and more specifically, the maximum value of the demand power) of housing complex 40 is realized. For example, as indicated in (b) of FIG. 3, situations where the maximum value of the demand power exceeds the first reference power are suppressed. This makes it less likely that the base rate for housing complex 40 will rise.

[0076] The time range over which the boiling start time can be changed is shorter for water heater 11 having an earlier latest boiling start time than for water heater 11 having a later latest boiling start time. For example, as illustrated in FIG. 3, if the boiling by second water heater 11b does not start between time t0 and time t12, the hot water from second water heater 11b will run out. On the other hand, the boiling by third water heater 11c may start between time t0 and time t13, and the hot water from third water heater 11c will not run out even if the boiling starts between time t12 and time t13, unlike second water heater 11b.

[0077] In this manner, determiner 130 determining a schedule in which boiling by water heater 11 having a shorter time range over which the boiling start time can be changed (here, second water heater 11b) is prioritized makes it less likely that the hot water from second water heater 11b will run out.

[0078] More detailed processing in step S30 will now be described with reference to FIGS. 4 and 5.

[0079] FIG. 4 is a more detailed flowchart illustrating step S30 of Operation Example 1 according to the present embodiment. FIG. 5 is another diagram illustrating a schedule of Operation Example 1 according to the present embodiment. More specifically, (a) of FIG. 5 is a diagram illustrating the schedule when the plurality of water heaters 11 start boiling simultaneously, in the same manner as (a) of FIG. 3, and (b) of FIG. 5 illustrates the schedule when the start of boiling by second water heater 11b is delayed.

[0080] In FIGS. 4 and 5, the latest boiling start time of first water heater 11a is t11, the latest boiling start time of second water heater 11b is t12, and the latest boiling start time of third water heater 11c is t13. t11 is a time earlier than t12 and t13, and t12 and t13 are the same time.

[0081] As illustrated in FIG. 4, in step S30, determiner 130 determines a schedule that starts boiling in order from water heater 11 for which the latest boiling start time is the earliest among the plurality of water heaters 11.

[0082] More specifically, determiner 130 determines whether two water heaters 11 for which the latest boiling start time is the same time are present among the plurality of water heaters 11 (S30a).

[0083] If two water heaters 11 for which the latest boiling start time is the same time are present (Yes in step S30a), determiner 130 determines the following schedule. In this case, determiner 130 determines a schedule that starts boiling in order from water heater 11, among the two water heaters 11, having the highest boiling amount included in the hot water supply information for that water heater 11 (S30b).

[0084] Steps S30a and S30b will be described in more detail with reference to FIG. 5.

[0085] As described above, t11 is a time earlier than t12 and t13. Accordingly, first, determiner 130 determines a schedule that expedites the start of boiling by first water heater 11a for which, among first to third water heaters 11a to 11c, the latest boiling start time is earlier than second and third water heaters 11b and 11c.

[0086] t12 and t13 are the same time. Here, the boiling amount included in the hot water supply information for third water heater 11c is higher than the boiling amount included in the hot water supply information for second water heater 11b. Accordingly, determiner 130 determines a schedule that expedites the start of boiling by third water heater 11c, which has a higher boiling amount than second water heater 11b, among second and third water heaters 11b and 11c (the schedule indicated in (b) of FIG. 5).

[0087] The processing of step S90 is then performed.

[0088] Water heater 11 having a higher boiling amount requires a longer time for boiling. In Operation Example 1 illustrated in FIGS. 4 and 5, the schedule is determined such that boiling by water heater 11 having a high boiling amount in this manner (e.g., third water heater 11c) is performed preferentially, which makes it less likely that water heater 11 will run out of hot water. Having water heater 11 that has a high boiling amount perform boiling in a time slot when the power unit price is lower (the second time slot) provides a greater electricity rate reduction effect than having that water heater 11 perform boiling in the first time slot. Accordingly, determining the schedule such that water heater 11 having a higher boiling amount boils preferentially reduces the electricity rate paid by the owner of that water heater 11.

[0089] Operation Example 1 may also be configured as follows.

[0090] The boiling amounts of first to fifth water heaters 11a to 11e may be different from each other, and the usage start times of first to fifth water heaters 11a to 11e may be different from each other. In other words, each of the owners of first to fifth individual dwellings 10a to 10e can set a preferred numerical value by operating the acceptor of control device 13.

[0091] As described above, the hot water supply information for each of first to fifth water heaters 11a to 11e includes the boiling amount and the usage start time for that water heater 11. In the present embodiment, the hot water supply information for each of first to fifth water heaters 11a to 11e is determined by the owner operating the acceptor of control device 13, but the configuration is not limited thereto.

[0092] For example, the manager of hot water supply system 100 may obtain information about the boiling amounts and the usage start times by conducting a questionnaire on the use of hot water with the owners of first to fifth individual dwellings 10a to 10e. By controlling an information terminal such as a smartphone, a tablet, or a personal computer, the manager sends information about the boiling amounts and the usage start times to communicator 110 of hot water supply system 100. Obtainer 120 of hot water supply system 100 may obtain the information about the boiling amounts and the usage start times, and determine these as the boiling amounts and the usage start times for first to fifth water heaters 11a to 11e, respectively. The questionnaire also asks each owner about the types of hot water usage (bathing, showering, or other household chores), the hot water usage amount for each type, and the timing of each behavior, in each season, for first to fifth individual dwellings 10a to 10e.

[0093] Additionally, for example, the hot water supply information for first to fifth water heaters 11a to 11e may be determined based on past usage data, rather than a questionnaire as described above. It is desirable that the boiling amount and the usage start time in a past predetermined period for first water heater 11a, for example, be stored as the past usage data in storage 150 of hot water supply system 100. The past predetermined period is, for example, a period from the day before the one day back to one week prior thereto, but is not limited thereto. Obtainer 120 may obtain the hot water supply information based on the past usage data. For example, the boiling amount included in the hot water supply information based on the past usage data is an average value of the boiling amounts from the past predetermined period. Additionally, for example, the usage start time included in the hot water supply information based on the past usage data is an average value of the usage start times from the past predetermined period.

[0094] For example, the hot water supply information for first to fifth water heaters 11a to 11e may be determined based on life schedule information obtained from the information terminals of the owners of first to fifth individual dwellings 10a to 10e. If the owner is using a schedule management app on their smartphone, which is an example of an information terminal, control device 13 may obtain, from the information terminal, the life schedule information, which indicates a daily life schedule of the owner. The boiling amount and usage start time included in the hot water supply information may be determined based on the obtained life schedule information. In addition, by accepting an operation instructing a target boiling amount and an operation instructing a usage start time from the owner, the information terminal may output information instructing the target boiling amount and the usage start time to control device 13. The hot water supply information may be determined in this manner.[Operation Example 2]

[0095] FIG. 6 is a flowchart of Operation Example 2 according to the present embodiment. FIG. 7 is a diagram illustrating a schedule of Operation Example 2 according to the present embodiment.

[0096] Operation Example 2 will describe an example in which three types of time slots having different power unit prices (first to third time slots) are provided, and a schedule for boiling by one water heater 11 (here, first water heater 11a) is determined.

[0097] As illustrated in FIG. 6, the processing of step S10 is performed first, in the same manner as in FIG. 2.

[0098] Then, obtainer 120 obtains the first power unit price for the first time slot and the second power unit price for the second time slot. More specifically, obtainer 120 obtains the first power unit price for the first time slot, the second power unit price for the second time slot, and the third power unit price for the third time slot (S11). Obtainer 120 obtains the first power unit price, the second power unit price, and the third power unit price stored in storage 150, for example.

[0099] The power unit price is the electricity rate per kWh, and is a value that varies depending on the time slot. The first power unit price is Y yen / kWh, the second power unit price is X yen / kWh, and the third power unit price is Z yen / kWh. In addition, the second power unit price is cheaper than the first power unit price, and the first power unit price is cheaper than the third power unit price.

[0100] In Operation Example 2, the second time slot is from 11 PM to 7 AM the next day, the first time slot is from 7 AM to 12 PM, and the third time slot is from 12 PM to 11 PM. The second time slot, the first time slot, and the third time slot are consecutive time slots.

[0101] Determiner 130 determines a schedule based on the first power unit price and the second power unit price obtained by obtainer 120 to lower the electricity rate from the boiling by the plurality of water heaters 11. In the present operation example, the schedule is determined to lower the electricity rate from the boiling by first water heater 11a based on the first to third power unit prices obtained by obtainer 120 (S31).

[0102] Step S31 will be described in more detail with reference to FIG. 7.

[0103] As described above, the second power unit price is cheaper than the first power unit price and the first power unit price is cheaper than the third power unit price, and determiner 130 therefore determines a schedule such that the boiling by first water heater 11a is performed during the second time slot in which the power unit price is the lowest. Furthermore, as illustrated in FIG. 7, determiner 130 determines a schedule in which if the boiling by first water heater 11a is not completed during the second time slot, the remaining boiling is performed during the first time slot, in which the power unit price is the second lowest.

[0104] The processing of step S90 is then performed in the same manner as in FIG. 2.

[0105] In Operation Example 2, the boiling by water heater 11 (e.g., first water heater 11a) is performed during a time slot in which the power unit price is lower, which makes it possible to reduce the electricity rate paid by the owner of water heater 11.[Operation Example 3]

[0106] FIG. 8 is a flowchart of Operation Example 3 according to the present embodiment. FIG. 9 is a diagram illustrating a schedule of Operation Example 3 according to the present embodiment. (a) of FIG. 9 illustrates a schedule for boiling by first water heater 11a during a second time slot starting at an earlier time, and (b) of FIG. 9 illustrates a schedule for boiling by first water heater 11a during a second time slot starting at a later time.

[0107] Operation Example 3 will describe an example in which two types of time slots having different power unit prices (first and second time slots) are provided, and a schedule for boiling by one water heater 11 (here, first water heater 11a) is determined. In the present operation example, two of the second time slots are provided for one day, i.e., a plurality of the second time slots are provided. For identification, the second time slot starting at an earlier time in FIG. 9 will be referred to as second time slot A, and the second time slot starting at a later time will be referred to as second time slot B.

[0108] As illustrated in FIG. 8, the processing of step S10 is performed first, in the same manner as in FIG. 2.

[0109] Then, obtainer 120 obtains the first power unit price for the first time slot and the second power unit price for the second time slot (S12). Obtainer 120 obtains the first power unit price and the second power unit price stored in storage 150, for example.

[0110] As in Operation Example 2, the first power unit price is Y yen / kWh, and the second power unit price is X yen / kWh. The second power unit price is cheaper than the first power unit price.

[0111] Determiner 130 determines the following schedule based on the first power unit price and the second power unit price obtained by obtainer 120 and the usage start time included in each of the plurality of items of hot water supply information obtained by obtainer 120. Determiner 130 determines the schedule such that the electricity rate from the boiling by each of the plurality of water heaters 11 is reduced, and a time difference between a first expected completion time, which is the time at which the boiling by each of the plurality of water heaters 11 is expected to be completed, and the usage start time, is shortened (S32). In the present operation example, determiner 130 determines the schedule based on the first power unit price, the second power unit price, and the usage start time, to reduce the electricity rate from the boiling by first water heater 11a, and to shorten the time difference between the first expected completion time and the usage start time. In this manner, determiner 130 determines the schedule such that the time difference between the first expected completion time and the usage start time is shortened, and more specifically, determines the schedule such that the time difference is within a predetermined time period. The predetermined time period may be, for example, at least 30 minutes and no greater than 8 hours, and it is desirable that the predetermined time period be a time period determined by the manager of hot water supply system 100 in advance.

[0112] Step S32 will be described in more detail with reference to FIG. 9.

[0113] As described above, the second power unit price is cheaper than the first power unit price, and determiner 130 therefore determines the schedule such that the boiling by first water heater 11a is performed during the second time slot in which the power unit price is the lowest. Furthermore, determiner 130 determines a schedule in which if the boiling by first water heater 11a is not completed during the second time slot, the remaining boiling is performed during the first time slot, in which the power unit price is the second lowest. It is therefore possible that two schedules will be determined, as indicated in (a) and (b) of FIG. 9.

[0114] Furthermore, in the present operation example, the time at which second time slot B, which starts at a later time, ends, is the usage start time at which the owner starts using hot water, as illustrated in FIG. 9. The first expected completion time is the time at which boiling by water heater 11 (here, first water heater 11a) is completed in the schedule. In the example illustrated in (a) of FIG. 9, the first expected completion time is included in the first time slot, and in the example illustrated in (b) of FIG. 9, the first expected completion time is the time at which second time slot B has ended, and is included in second time slot B.

[0115] Determiner 130 then determines the schedule to reduce the time difference between the first expected completion time and the usage start time for first water heater 11a. The time difference between the first expected completion time and the usage start time in the schedule illustrated in (b) of FIG. 9 is shorter than the time difference between the first expected completion time and the usage start time in the schedule illustrated in (a) of FIG. 9. Determiner 130 therefore determines the schedule illustrated in (b) of FIG. 9 as a schedule that reduces the electricity rate from the boiling by first water heater 11a and reduces the time difference between the first expected completion time and the usage start time.

[0116] The processing of step S90 is then performed.

[0117] In Operation Example 3, the boiling by water heater 11 (e.g., first water heater 11a) is performed during a time slot in which the power unit price is lower, which makes it possible to reduce the electricity rate paid by the owner of water heater 11.

[0118] Additionally, for example, as indicated in (a) of FIG. 9, if the time from the first expected completion time to the usage start time is long, a problem arises in that the boiled water cools down. However, in Operation Example 3, as indicated in (b) of FIG. 9, the time difference between the first expected completion time and the usage start time is short, which makes it unlikely that the stated problem will arise.[Operation Example 4]

[0119] FIG. 10 is a flowchart of Operation Example 4 according to the present embodiment. FIG. 11 is a diagram illustrating a schedule of Operation Example 4 according to the present embodiment.

[0120] Operation Example 4 is operations in which, for example, in step S90 in Operation Example 1, controller 140 is controlling the boiling by the plurality of water heaters 11 (first and second water heaters 11a and 11b) in the second time slot based on the schedule determined. More specifically, these are operations in which first and second water heaters 11a and 11b are in the middle of boiling.

[0121] As described above, in Operation Example 1, obtainer 120 obtains the second used power, which corresponds to the expected power amount in the second time slot for the electrical equipment aside from the plurality of water heaters 11 in housing complex 40. However, it is also possible that an amount of power exceeding the expected power amount will be consumed. Operation Example 4 is operations performed under the assumption that in step S90, when boiling by the plurality of water heaters 11 is performed, the power amount of the electrical equipment aside from the plurality of water heaters 11 in housing complex 40 exceeds the expected power amount.

[0122] Obtainer 120 obtains the first used power, at the present time, of the electrical equipment in housing complex 40 aside from the plurality of water heaters 11 in the second time slot (step S13). Note that obtainer 120 obtains the first used power as follows.

[0123] In step S13, obtainer 120 obtains, through communicator 110, the individual dwelling power information about the power used by electrical equipment 12 and the common area power information about the power used by electrical equipment 21. As described above, in the present embodiment, the electrical equipment aside from the plurality of water heaters 11 is constituted by all of the plurality of electrical equipment 12 in the plurality of households and electrical equipment 21 in common area 20. The first used power is information that integrates the used power at the present time (the second time slot) for electrical equipment 12, indicated by the individual dwelling power information, and the used power at the present time (the second time slot) for electrical equipment 21, indicated by the common area power information.

[0124] In other words, by having obtainer 120 obtain the individual dwelling power information and the common area power information, obtainer 120 obtains the first used power, at the present time, of the electrical equipment aside from the plurality of water heaters 11 in housing complex 40, in the second time slot. The first used power can also be said to be a measured value of the power of the electrical equipment aside from the plurality of water heaters 11 at the present time (the second time slot).

[0125] Next, based on the boiling amount included in the plurality of items of hot water supply information and the first used power obtained, determiner 130 determines whether the overall demand power of housing complex 40 at the present time (the second time slot) exceeds the first reference power obtained (S23). In other words, in step S23, it is determined whether the demand power will still exceed the first reference power even if the start of boiling by any one water heater 11 is delayed in step S30 of Operation Example 1. In other words, determiner 130 predicts and determines whether the demand power will exceed the reference power based on the first used power, which is the measured value of the power of the electrical equipment aside from the plurality of water heaters 11, after the start of the second time slot (in step S23).

[0126] Furthermore, if it is determined that the demand power will exceed the first reference power in the second time slot (Yes in step S23), determiner 130 updates the schedule as follows, based on the determined schedule. That is, determiner 130 updates the schedule determined in step S30 to stop the boiling by water heater 11 for which the time difference between the second expected completion time and the third expected completion time is greatest (S33). Note that the second expected completion time is a time at which boiling indicated by the schedule determined in step S30 is expected to be completed. The third expected completion time is a time at which boiling is expected to be completed when boiling is started at the latest boiling start time.

[0127] The processing of step S33 will be described with reference to FIG. 11.

[0128] (a) of FIG. 11 is a diagram illustrating a schedule when it is determined that the demand power will exceed the first reference power. For example, as indicated in (a) of FIG. 11, at time t2 (the current time), the first used power for the electrical equipment aside from the plurality of water heaters 11 is obtained, and it is determined that the demand power will exceed the first reference power in the second time slot (and more specifically, after time t2). In such a case, determiner 130 updates the schedule to stop boiling by water heater 11, among the plurality of water heaters 11, for which the time difference between the second expected completion time and the third expected completion time is greatest.

[0129] The second expected completion time and the third expected completion time will be described in more detail here.

[0130] The second expected completion time is a time at which boiling by water heater 11 is expected to be completed, as indicated by the schedule determined in step S30, for example. For example, (a) of FIG. 11 indicates that the second expected completion time of first water heater 11a is t21, and the second expected completion time of second water heater 11b is t22. t21 and t22 are the same time.

[0131] The third expected completion time is a time at which boiling is expected to be completed when the boiling by water heater 11 is started at the latest boiling start time. For example, (a) of FIG. 11 indicates that the third expected completion time of first water heater 11a is t31, and the third expected completion time of second water heater 11b is t32. t31 is a time earlier than t32.

[0132] In step S33, determiner 130 updates the schedule to stop the boiling by water heater 11, among the plurality of water heaters 11 (here, first and second water heaters 11a and 11b), for which the time difference between the second expected completion time and the third expected completion time is greatest. As illustrated in (a) of FIG. 11, the time difference between the second expected completion time and the third expected completion time of second water heater 11b is greater than the time difference between the second expected completion time and the third expected completion time of first water heater 11a. Accordingly, determiner 130 updates the schedule to stop the boiling by second water heater 11b among first and second water heaters 11a and 11b. More specifically, determiner 130 updates the schedule to stop the boiling by second water heater 11b at current time t2.

[0133] (b) of FIG. 11 is a diagram illustrating the schedule in which the boiling by second water heater 11b has been stopped, i.e., the updated schedule. Note that the present embodiment is not limited to the example indicated in (b) of FIG. 11, and the boiling by the plurality of water heaters 11 may be stopped. Additionally, the first used power is obtained every set period of time (e.g., every five minutes), and a time slot in which the first used power decreases after t21 is present, the schedule may be updated so that the boiling by second water heater 11b is started again.

[0134] Compared to water heater 11 for which the time difference between the second expected completion time and the third expected completion time is small, for water heater 11 for which the time difference is large, even if the boiling is paused, the time from the time at which the boiling is paused to the expected usage time is long. Accordingly, compared to water heater 11 for which the time difference is small, for water heater 11 for which the time difference is large, even if the boiling is paused, performing the boiling again makes it more likely that the boiling will be completed by the usage start time. Accordingly, having determiner 130 update the schedule to stop the boiling by water heater 11 for which the time difference is large (e.g., second water heater 11b) makes it less likely that water heater 11 for which the time difference is small and water heater 11 for which the time difference is large will run out of hot water.

[0135] Furthermore, controller 140 controls the boiling by the plurality of water heaters 11 in the second time slot based on the schedule updated by determiner 130 in step S33 (S53a).

[0136] Note that if it is determined that the demand power will not exceed the first reference power in the second time slot (No in step S23), controller 140 performs the following processing. In this case, controller 140 controls the boiling by the plurality of water heaters 11 in the second time slot based on the schedule determined by determiner 130 in step S30 (S53b).

[0137] In Operation Example 4, if, during the second time slot, the demand power exceeds the first reference power, hot water supply system 100 suppresses situations where the demand power exceeds the first reference power by updating the schedule to stop the boiling by water heater 11 (second water heater 11b). In other words, hot water supply system 100 capable of suppressing the overall demand power (and more specifically, the maximum value of the demand power) of housing complex 40 is realized. Additionally, as described above, having determiner 130 update the schedule to stop the boiling by water heater 11 for which the time difference between the second expected completion time and the third expected completion time is large makes it less likely that water heater 11 for which the time difference is small and water heater 11 for which the time difference is large will run out of hot water.

[0138] In Operation Example 4, the schedule is updated in the second time slot, but the configuration is not limited thereto. For example, the schedule may be updated in the first time slot, and control of the boiling by the plurality of water heaters 11 may be performed in the first time slot. Additionally, for example, in the example illustrated in (b) of FIG. 1B, the schedule may be updated in a predetermined time slot (e.g., 12 PM to 2 PM), and the boiling by the plurality of water heaters 11 may be controlled in the predetermined time slot.[Operation Example 5]

[0139] FIG. 12 is a flowchart of Operation Example 5 according to the present embodiment. FIG. 13 is a diagram illustrating a schedule of Operation Example 5 according to the present embodiment.

[0140] Operation Example 5 is operations in which, for example, in step S90 in Operation Example 1, controller 140 is controlling the boiling by two or more water heaters 11 (first and second water heaters 11a and 11b) in the second time slot based on the schedule determined. More specifically, these are operations in which first and second water heaters 11a and 11b are in the middle of boiling.

[0141] Like Operation Example 4, Operation Example 5 is operations performed under the assumption that in step S90, when boiling by the two or more water heaters 11 is performed, the power amount of the electrical equipment aside from the plurality of water heaters 11 in housing complex 40 exceeds the expected power amount.

[0142] Obtainer 120 obtains the first used power, at the present time, of the electrical equipment in housing complex 40 aside from the plurality of water heaters 11 in the second time slot (step S13). As described above, the first used power can also be said to be a measured value of the power of the electrical equipment aside from the plurality of water heaters 11 at the present time (the second time slot).

[0143] Furthermore, obtainer 120 obtains a boiling instruction instructing boiling by an other water heater 11 other than the two or more water heaters 11 (first and second water heaters 11a and 11b) (S14). Here, it is assumed that other water heater 11 is third water heater 11c. The boiling instruction indicates the boiling amount of that water heater 11 (here, third water heater 11c).

[0144] For example, obtainer 120 may obtain the boiling instruction when an information processing device accepts an operation from the owner of third water heater 11c (i.e., the owner of third individual dwelling 10c). The information processing device is control device 13 owned by the owner, an information terminal such as a smartphone, a tablet, or a personal computer, or the like.

[0145] If the owner of third water heater 11c wishes to use hot water, they operate an acceptor of control device 13, which is an example of the information processing device. In other words, the acceptor accepts an operation instructing boiling by third water heater 11c. As a result, control device 13 outputs the boiling instruction to communicator 110 in accordance with the accepted operation. Obtainer 120 then obtains the boiling instruction obtained by communicator 110.

[0146] Note that by operating the information terminal such as a smartphone, a tablet, or a personal computer, which is an example of an information processing terminal, the owner of third water heater 11c may output the boiling instruction from the information terminal to control device 13. Through this, control device 13 obtains the boiling instruction that has been output, and outputs the boiling instruction obtained to communicator 110. Obtainer 120 then obtains the boiling instruction obtained by communicator 110.

[0147] In this manner, in step S14, obtainer 120 obtains the boiling instruction for third water heater 11c.

[0148] Based on the boiling amount included in the hot water supply information for the two or more water heaters 11, the first used power obtained, and the boiling instruction obtained, determiner 130 determines whether the overall demand power of housing complex 40 at the present time (the second time slot) exceeds the first reference power obtained (S24). In other words, determiner 130 makes this determination based on the boiling amounts of first and second water heaters 11a and 11b, the first used power, and the boiling amount of third water heater 11c included in the boiling instruction.

[0149] If the demand power is determined to exceed the first reference power in the second time slot (Yes in step S24), determiner 130 updates the schedule as follows, based on the schedule determined in step S30 and the boiling instruction obtained in step S14. That is, determiner 130 updates the schedule to stop boiling by water heater 11, among the two or more water heaters 11, for which the time difference between the second expected completion time and the third expected completion time is the greatest, and start boiling by other water heater 11 (S34a). In the present operation example, determiner 130 updates the schedule to stop the boiling by water heater 11, among first and second water heaters 11a and 11b, for which the time difference between the second expected completion time and the third expected completion time is greatest, and to start the boiling by third water heater 11c.

[0150] The processing of steps S24 and S34A will be described with reference to FIG. 13.

[0151] (a) of FIG. 13 is a diagram illustrating the schedule determined in step S30. (b) of FIG. 13 is a diagram illustrating a schedule in which the boiling by third water heater 11c is added to the schedule in which the boiling by first and second water heaters 11a and 11b is performed, indicated in (a) of FIG. 13. The schedule indicated in (b) of FIG. 13 is a diagram illustrating a schedule when it is determined that the demand power will exceed the first reference power. For example, as indicated in (b) of FIG. 13, the first used power for the electrical equipment aside from the plurality of water heaters 11 and the boiling instruction for third water heater 11c are obtained at time t2 (the current time). At this time, it is determined that the demand power will exceed the first reference power in the second time slot (and more specifically, after time t2). In such a case, determiner 130 updates the schedule to stop the boiling by water heater 11, among the two or more water heaters 11, for which the time difference between the second expected completion time and the third expected completion time is the greatest, and start the boiling by other water heater 11.

[0152] In step S34a, determiner 130 updates the schedule to stop the boiling by water heater 11, among the two or more water heaters 11 (here, first and second water heaters 11a and 11b), for which the time difference between the second expected completion time and the third expected completion time is greatest. As indicated in (b) of FIG. 13, the time difference between the second expected completion time and the third expected completion time of second water heater 11b is greater than the time difference between the second expected completion time and the third expected completion time of first water heater 11a. Accordingly, determiner 130 updates the schedule to stop the boiling by second water heater 11b among first and second water heaters 11a and 11b.

[0153] As in Operation Example 4, having determiner 130 update the schedule to stop the boiling by water heater 11 for which the time difference is large makes it less likely that water heater 11 for which the time difference is small and water heater 11 for which the time difference is large will run out of hot water.

[0154] In this manner, hot water supply system 100 suppresses situations where the demand power exceeds the first reference power by updating the schedule to stop the boiling by water heater 11 (second water heater 11b). In other words, hot water supply system 100 capable of suppressing the overall demand power (and more specifically, the maximum value of the demand power) of housing complex 40 is realized.

[0155] Furthermore, in step S34a, determiner 130 updates the schedule to start the boiling by other water heater 11 (third water heater 11c). More specifically, determiner 130 updates the schedule such that the boiling by third water heater 11c begins at time t2 or later. Note that determiner 130 preferably updates the schedule such that the boiling by third water heater 11c begins at an early time following time t2 (a time within several minutes from time t2, for example).

[0156] (c) of FIG. 13 is a diagram illustrating the schedule in which the boiling by second water heater 11b has been stopped and the boiling by third water heater 11c has been started, i.e., the updated schedule. As indicated in (c) of FIG. 13, the boiling by second water heater 11b, which has been paused, may be repeated after the end of the boiling by third water heater 11c.

[0157] Furthermore, controller 140 controls the boiling by the plurality of water heaters 11 in the second time slot based on the schedule updated by determiner 130 in step S34a (S54a).

[0158] If the demand power is determined not to exceed the first reference power in the second time slot (No in step S24), determiner 130 updates the schedule as follows, based on the schedule determined in step S30 and the boiling instruction obtained in step S14. That is, determiner 130 updates the schedule to start the boiling by other water heater 11 (S34b). Determiner 130 updates the schedule to be a schedule in which the boiling by third water heater 11c is added to the schedule in which the boiling by first and second water heaters 11a and 11b is performed, indicated in (a) of FIG. 13.

[0159] Next, controller 140 controls the boiling by the plurality of water heaters 11 in the second time slot based on the schedule updated by determiner 130 in step S34b (S54b).

[0160] In Operation Example 5, hot water supply system 100 performs the following processing when the boiling instruction of other water heater 11 (third water heater 11c) is obtained during the second time slot. That is, hot water supply system 100 updates the schedule to start the boiling by other water heater 11. Through this, hot water supply system 100 can perform the boiling by other water heater 11.

[0161] In Operation Example 4 and Operation Example 5, the boiling by second water heater 11b for which, among the plurality of water heaters 11 (first and second water heaters 11a and 11b), the time difference between the second expected completion time and the third expected completion time is greatest, is stopped, but the configuration is not limited thereto.

[0162] For example, the manager of hot water supply system 100 may obtain information about the stopping of boiling for each of the plurality of owners by conducting a questionnaire on the stopping of the boiling with the owners of first to fifth individual dwellings 10a to 10e. By controlling an information terminal such as a smartphone, a tablet, or a personal computer, the manager sends information about the stopping of the boiling to communicator 110 of hot water supply system 100. Obtainer 120 of hot water supply system 100 obtains the information about the stopping of the boiling. As described in Operation Example 4 and Operation Example 5, the questionnaire asks the owner whether it is acceptable to stop the boiling by water heater 11 owned by that owner when the overall demand power of housing complex 40 exceeds the first reference power obtained. Information about the stopping of boiling for one owner indicates whether it is acceptable to stop the boiling by water heater 11 owned by the one owner.

[0163] As one example, assume that the information about the stopping of boiling for the owner of first water heater 11a indicates that it is acceptable to stop the boiling by first water heater 11a. Furthermore, assume that the information about the stopping of boiling for the owner of second water heater 11b indicates that it is not acceptable to stop the boiling by second water heater 11b.

[0164] In such a case, in step S33 of Operation Example 4 and step S34a of Operation Example 5, determiner 130 performs the following processing. That is, based on the information about stopping the boiling for the owners of first water heater 11a and second water heater 11b, determiner 130 updates the schedule to stop the boiling by first water heater 11a among first water heater 11a and second water heater 11b. In other words, if the owner agrees to stop the boiling, the boiling by water heater 11 owned by that owner is stopped. If the owner does not agree to stop the boiling, the boiling by water heater 11 owned by that owner is not stopped. In other words, determiner 130 updates the schedule according to the owner's wishes.

[0165] In Operation Example 4 and Operation Example 5, stopping the boiling by water heater 11 may cause the boiling by that water heater 11 to be performed in a time slot having a higher power unit price (e.g., the first time slot). As a result, the electricity rate paid by the owner of water heater 11 will be higher than when the boiling by that water heater 11 is performed in a time slot having a lower power unit price. In such a case, a display of hot water supply system 100 displays the monetary amount of the difference between the electricity rate when the boiling by water heater 11 is performed in a time slot having a lower power unit price and the electricity rate when the boiling by water heater 11 is performed in a time slot having a higher power unit price. The manager of hot water supply system 100 can make the owner more amenable to cooperating with stopping of the boiling by paying the displayed monetary amount to the owner.

[0166] Furthermore, there are cases where the boiling by one water heater 11 is stopped and then performed in a time slot having a higher power unit price for a predetermined period of time (e.g., two days). Such cases are likely to occur especially in winter, when there is increased demand for hot water.

[0167] When such a case occurs, the following processing may be performed to suppress the electricity rate paid by the owners in housing complex 40 as a whole. That is, when such a case occurs, during one season including the predetermined period (e.g., winter), hot water supply system 100 deems that the boiling by water heater 11 is performed during a time slot having a higher power unit price. Hot water supply system 100 compares the monetary amount when the difference occurs throughout the one season, with the amount of the price increase in the electricity rate for the current year when a contract with a high base rate in the current month and the 11 months from the following month has been entered into due to the boiling by water heater 11 not being stopped and the demand power exceeding the first reference power. If hot water supply system 100 determines that the amount of the price increase is lower, the demand power is permitted to exceed the first reference power, and the first reference power is changed to a higher first reference power after that date. In other words, hot water supply system 100 determines a schedule based on the changed higher first reference power after the date.

[0168] Note that the predetermined period is not limited to two days, and may be, for example, several days, a week, or a month.

[0169] In Operation Example 5, the schedule is updated in the second time slot, but the configuration is not limited thereto. For example, the schedule may be updated in the first time slot, and control of the boiling by the plurality of water heaters 11 may be performed in the first time slot. Additionally, for example, in the example illustrated in (b) of FIG. 1B, the schedule may be updated in a predetermined time slot (e.g., 12 PM to 2 PM), and the boiling by the plurality of water heaters 11 may be controlled in the predetermined time slot.[Operation Example 6]

[0170] FIG. 14 is a flowchart of Operation Example 6 according to the present embodiment. FIG. 15 is a diagram illustrating a schedule of Operation Example 6 according to the present embodiment.

[0171] Operation Example 6 is operations in which, for example, after determiner 130 determines the schedule in step S30 in Operation Example 1, determiner 130 reviews and re-determines the schedule determined.

[0172] Operation Example 6 will describe an example in which two types of time slots having different power unit prices (first and second time slots) are provided, and a schedule for boiling by one water heater 11 (here, first water heater 11a) is determined. In the present operation example, two of the second time slots are provided for one day, i.e., a plurality of the second time slots are provided. For identification, the second time slot starting at an earlier time in FIG. 15 will be referred to as second time slot A, and the second time slot starting at a later time will be referred to as second time slot B.

[0173] After step S30 is performed, determiner 130 makes the following determination based on the usage start time included in each of the plurality of items of hot water supply information obtained by obtainer 120. In other words, determiner 130 determines whether the plurality of water heaters 11 include a first target water heater for which the time from the second expected completion time to the usage start time exceeds a reference time (S60). The second expected completion time is a time at which boiling indicated by the schedule determined by determiner 130 in step S30 is expected to be completed.

[0174] The reference time may be, for example, at least 30 minutes and no greater than 8 hours, and it is desirable that the predetermined time period be a time period determined by the manager of hot water supply system 100 in advance.

[0175] Furthermore, if the first target water heater for which the time from the second expected completion time to the usage start time exceeds the reference time is determined to be present (Yes in step S60), determiner 130 performs the following processing. In other words, determiner 130 re-determines the schedule to temporarily stop the boiling by the first target water heater in the second time slot, start the boiling again, and complete the boiling by the first target water heater by the usage start time (S70).

[0176] The processing of steps S60 and S70 will be described with reference to FIG. 15.

[0177] (a) in FIG. 15 is a diagram illustrating a schedule when it is determined that the first target water heater (here, first water heater 11a) is present when the time from the second expected completion time to the usage start time exceeds the reference time. (a) of FIG. 15 is a diagram illustrating the schedule determined in step S30 of Operation Example 1, for example.

[0178] Additionally, for example, as indicated in (a) of FIG. 15, if the time from the second expected completion time to the usage start time exceeds the reference time, i.e., if the time from the second expected completion time to the usage start time is long, a problem arises in that the boiled water cools down. Accordingly, determiner 130 re-determines the schedule such that in the second time slot (here, second time slot A), the boiling by the first target water heater is stopped temporarily, and in the second time slot (here, second time slot B), the boiling is performed again. At this time, determiner 130 re-determines the schedule such that the time from the time when the boiling by the first target water heater is completed to the expected usage time drops below the reference time due to the boiling being performed again.

[0179] (b) of FIG. 15 is a diagram illustrating the schedule in which the boiling by first water heater 11a is temporarily stopped and the boiling is performed again, i.e., the re-determined schedule. Note that the configuration is not limited to the example indicated in (b) of FIG. 15, and in the present operation example, if a plurality of first target water heaters are present, determiner 130 performs the following processing. That is, determiner 130 may re-determine the schedule to temporarily stop the boiling by the plurality of first target water heaters after that boiling, and then start the boiling again such that the boiling by the plurality of first target water heaters is completed by the usage start time.

[0180] Furthermore, controller 140 controls the boiling by the plurality of water heaters 11 in the second time slot based on the schedule re-determined by determiner 130 in step S70 (S90).

[0181] Note that if the first target water heater for which the time from the second expected completion time to the usage start time exceeds the reference time is determined not to be present (No in step S60), controller 140 performs the following processing. In this case, controller 140 controls the boiling by the plurality of water heaters 11 in the second time slot based on the schedule determined by determiner 130 in step S30 (S90).

[0182] In addition, as illustrated in FIG. 15, in the present operation example, the second expected completion time is included in the first time slot in the schedule determined in step S30. In this schedule, the electricity rate increases compared to when the boiling by the first target water heater (first water heater 11a) is completed in the second time slot alone.

[0183] Accordingly, if the second expected completion time is included in the first time slot, determiner 130 may re-determine the schedule such that the boiling by the first target water heater (first water heater 11a) is completed in the second time slot only. Specifically, as illustrated in (b) of FIG. 15, determiner 130 re-determines the schedule such that when the boiling by the first target water heater (first water heater 11a) is not completed in second time slot A alone, the boiling is performed in second time slot B as well.

[0184] In Operation Example 6, two of the second time slots (second time slot A and second time slot B) are provided for one day, i.e., a plurality of the second time slots are provided, but the same processing may be performed even if only one of the second time slots is provided for one day. In other words, if determiner 130 determines that the first target water heater for which the time from the second expected completion time to the usage start time exceeds the reference time is present, the following processing is performed. Determiner 130 re-determines the schedule such that in one second time slot, the boiling by the first target water heater is stopped temporarily, and the boiling is performed again in that second time slot.

[0185] As indicated in (b) of FIG. 15, in Operation Example 6, the schedule is re-determined by determiner 130 to temporarily stop the boiling by the first target water heater, start the boiling again, and complete the boiling by the first target water heater by the usage start time. Note that determiner 130 re-determines the schedule such that the time from the time when the boiling by the first target water heater is completed to the expected usage time drops below the reference time due to the boiling being performed again. Accordingly, because the time from the time when the boiling by the first target water heater is completed to the expected usage time is sufficiently shortened, the problem that the boiled water cools down due to the time from the time when the boiling is completed (the second expected completion time) to the expected usage start time being long is unlikely to occur.[Operation Example 7]

[0186] FIG. 16 is a flowchart of Operation Example 7 according to the present embodiment.

[0187] Like Operation Example 6, Operation Example 7 is operations in which, for example, after determiner 130 determines the schedule in step S30 in Operation Example 1, determiner 130 reviews and re-determines the schedule determined.

[0188] As illustrated in FIG. 16, in Operation Example 7, after step S30 is performed, determiner 130 makes the following determination. In other words, determiner 130 determines whether the plurality of water heaters 11 include a second target water heater for which a boiling number indicated by the schedule determined by determiner 130 in step S30 is at least a predetermined number (S61).

[0189] "Boiling number" refers to the number of times water heater 11 performs boiling before the target boiling amount is reached. For example, in (a) of FIG. 15, the boiling number of first water heater 11a is one time, and in (b) of FIG. 15, the boiling number of first water heater 11a is two times. The predetermined number may be, for example, at least three times and no greater than ten times.

[0190] Furthermore, if a second target water heater having a boiling number that is at least the predetermined number is determined to be present (Yes in step S61), determiner 130 re-determines the schedule such that the boiling number of the second target water heater drops below the predetermined number (S71).

[0191] Furthermore, controller 140 controls the boiling by the plurality of water heaters 11 in the second time slot based on the schedule re-determined by determiner 130 in step S71 (S90).

[0192] Note that if a second target water heater for which the boiling number is at least the predetermined number is determined not to be present (No in step S61), controller 140 performs the following processing. In this case, controller 140 controls the boiling by the plurality of water heaters 11 in the second time slot based on the schedule determined by determiner 130 in step S30 (S90).

[0193] As described above, the predetermined number may be, for example, at least three times and no greater than ten times. As the number of instances of boiling increases, the boiling efficiency when water heater 11 is started up decreases, causing a problem that the amount of consumed power increases. In Operation Example 7, the boiling number of the second target water heater is less than the predetermined number, and thus such a problem is unlikely to occur. In other words, the amount of consumed power is suppressed, and thus hot water supply system 100 can suppress the overall demand power (and more specifically, the maximum value of the demand power) of housing complex 40.

[0194] In Operation Example 7, the schedule is re-determined in the first time slot, but the configuration is not limited thereto. For example, the schedule may be re-determined in the second time slot, and control of the boiling by the plurality of water heaters 11 may be performed in the first time slot. In the example illustrated in (b) of FIG. 1B, for example, the schedule may be re-determined by the start of a predetermined time slot (e.g., 12 PM to 2 PM), and the control of the boiling by the plurality of water heaters 11 may be performed in the predetermined time slot.[Operation Example 8]

[0195] FIG. 17 is a flowchart of Operation Example 8 according to the present embodiment. FIG. 18 is a diagram illustrating a schedule and an electricity rate of Operation Example 8 according to the present embodiment.

[0196] Like Operation Examples 6 and 7, Operation Example 8 is operations in which, for example, after determiner 130 determines the schedule in step S30 in Operation Example 1, determiner 130 reviews and re-determines the schedule determined.

[0197] In Operation Example 8, step S30 is performed, as illustrated in FIG. 17. Then, if determiner 130 determines that the second expected completion time of the boiling by third water heater 11c, for which the start of boiling was delayed in the schedule determined by determiner 130 in step S30, falls within the first time slot, determiner 130 performs the following processing. That is, determiner 130 determines whether a second price increase is lower than a first price increase (S62). As described above, the second time slot is from 11 PM to 7 AM the next day. In other words, the second expected completion time of the boiling by third water heater 11c falling within the first time slot means that the second expected completion time falls within the first time slot of the next day (from 7 AM on the next day to 11 PM on the next day).

[0198] The first price increase and the second price increase will be described here with reference to FIG. 18.

[0199] FIG. 18 is a diagram illustrating a schedule re-determined through the processing of Operation Example 8 according to the present embodiment. More specifically, (a) of FIG. 18 is a diagram illustrating a schedule in which the second expected completion time of the boiling by third water heater 11c, for which the start of boiling has been delayed, is included in the first time slot. (b) of FIG. 18 is a diagram illustrating a schedule when a demand power (rate Pb) exceeds a first reference power (rate Pa).

[0200] The first price increase will be described with reference to (a) of FIG. 18.

[0201] As described above, the first time slot is a time slot in which the power unit price is higher, and the second time slot is a time slot in which the power unit price is lower.

[0202] As indicated in (a) of FIG. 18, if the second expected completion time of the boiling by third water heater 11c falls within the first time slot, the electricity rate paid by the owner of third water heater 11c will be higher than if the boiling by third water heater 11c ends in the second time slot. The first price increase is a price increase in the electricity rate due to the second expected completion time of the boiling by third water heater 11c falling within the first time slot, compared to the electricity rate when the second expected completion time falls within the second time slot.

[0203] For example, assume that the power unit price in the second time slot is X (yen / kWh), the power unit price in the first time slot is Y (yen / kWh), and the power amount required by third water heater 11c to boil within the first time slot, indicated in (a) of FIG. 18, is W (kWh). In this case, the first price increase is expressed by Formula (1). W × Y − X

[0204] The second price increase will be described next with reference to (b) of FIG. 18.

[0205] The second price increase is an increase in the electricity rate due to the demand power (rate Pb) exceeding the first reference power (rate Pa) when the boiling by third water heater 11c is performed such that the second expected completion time of the boiling by third water heater 11c falls within the second time slot.

[0206] For example, assuming the rate at the demand power is Pb (yen) and the rate at the first reference power is Pa (yen), the second price increase for the boiling by third water heater 11c, indicated in (b) of FIG. 18, is expressed by Formula (2). Pb − Pa

[0207] Pb (yen), which is the rate at the demand power, is a rate that needs to be paid to the power company, for example, when the overall demand power is required by housing complex 40 in the event that the demand power exceeds the first reference power. The rate at the first reference power, namely Pa (yen), is a rate that needs to be paid to the power company, for example, when the overall demand power is required by housing complex 40 in the event that the demand power does not exceed the first reference power.

[0208] As illustrated in FIG. 17, when the second price increase is lower than the first price increase (yes in S62), determiner 130 increases the first reference power, and re-determines the schedule such that the second expected completion time of the boiling by third water heater 11c falls within the second time slot (S72). In other words, in this case, determiner 130 changes the reference power such that the reference power increases from the first reference power (rate Pa) to the first reference power (rate Pc) after the change and the demand power (rate Pb) becomes lower than the first reference power (rate Pc) after the change. As a result, determiner 130 re-determines the schedule to be the schedule indicated in (b) of FIG. 18.

[0209] Furthermore, controller 140 controls the boiling by the plurality of water heaters 11 in the second time slot based on the schedule re-determined by determiner 130 in step S72 (S90).

[0210] Note that if the second price increase is at least the first price increase (No in S62), controller 140 performs the following processing. In this case, controller 140 controls the boiling by the plurality of water heaters 11 in the second time slot based on the schedule determined by determiner 130 in step S30 (S90).

[0211] In Operation Example 8, by comparing the first price increase with the second price increase, hot water supply system 100 can re-determine the schedule such that the electricity rate is lower throughout the year.[Operation Example 9]

[0212] FIG. 19 is a flowchart of Operation Example 9 according to the present embodiment. FIG. 20 is a diagram illustrating a schedule of Operation Example 9 according to the present embodiment.

[0213] Like Operation Example 4, Operation Example 9 is operations in which, for example, in step S90 in Operation Example 1, controller 140 is controlling the boiling by the plurality of water heaters 11 (first to fourth water heaters 11a to 11d) in the second time slot based on the schedule determined. More specifically, these are operations in which first and second water heaters 11a and 11b are boiling, and as will be described later, at the time when step S25 according to Operation Example 9 is performed, third and fourth water heaters 11c and 11d are not yet boiling.

[0214] Operation Example 9 describes an example in which the second time slot includes a partial time slot, as illustrated in FIG. 20. As described above, the second time slot is from 11 PM to 7 AM the next day. The partial time slot is, for example, from 2 AM the next day to 4 AM the next day in the second time slot, but is not limited thereto.

[0215] The partial time slot will be described further.

[0216] There are cases where the need to conserve power rises sharply due to tight supply and demand of electricity or soaring electricity market prices. In such cases, it may be necessary to keep the demand power below the first reference power, or keeping the demand power below the first reference power may keep the electricity rate lower. In the present operation example, a time slot in which the reference power is set to be less than the first reference power in this manner is the partial time slot. It should be noted that it is often difficult to determine whether the need to conserve power will increase before the start of the second time slot. Accordingly, Operation Example 9 will be described assuming that at a stage such as step S30 of Operation Example 1 before Operation Example 9 is performed, the first reference power is used and the schedule is determined under the assumption that no such partial time slot will occur.

[0217] Furthermore, obtainer 120 obtains the second reference power for the partial time slot (S15). Obtainer 120 obtains the second reference power stored in storage 150. The second reference power is a reference power lower than the first reference power and is a reference power for housing complex 40 (the plurality of residences). Furthermore, the second reference power is also a reference power for the partial time slot included in the second time slot.

[0218] Note that before step S15 is performed, hot water supply system 100 may perform the following processing. As described above, if the need to conserve power rises sharply, an information terminal such as a smartphone, a tablet, or a personal computer accepts a predetermined operation from the manager of hot water supply system 100. The predetermined operation is an operation instructing obtainer 120 of hot water supply system 100 to obtain the second reference power. The information terminal sends information instructing obtainer 120 to obtain the second reference power to communicator 110 of hot water supply system 100. Obtainer 120 may obtain the second reference power in step S15 by obtaining that information from communicator 110 of hot water supply system 100.

[0219] Furthermore, determiner 130 determines whether the overall demand power of housing complex 40 (the plurality of residences) has exceeded the second reference power obtained by obtainer 120 in the partial time slot in the schedule determined in step S30 (S25). As described above, the schedule determined in step S30 is determined without using the second reference power, and the second reference power may therefore be exceeded in that schedule. In this manner, it can also be said that in Operation Example 9, the reference power is changed from the first reference power to the second reference power.

[0220] Next, if determiner 130 determines that the demand power will exceed the second reference power (Yes in S25), determiner 130 updates the schedule determined by determiner 130 in step S30 prior to the partial time slot, which here is the second time slot. In other words, determiner 130 updates the schedule to start boiling in order from water heater 11, among the plurality of water heaters 11, for which the latest boiling start time is earliest (S35). More specifically, determiner 130 updates the schedule to start the boiling in order from water heater 11 for which the latest boiling start time is the earliest, among the plurality of water heaters 11 that have not yet started the boiling at the time of step S25. As described above, at the time when Operation Example 9 begins, two or more water heaters 11 (first and second water heaters 11a and 11b) are boiling. Accordingly, in step S35, determiner 130 updates the schedule to start boiling in order from water heater 11, among the plurality of water heaters 11, which is not one of the two or more water heaters 11 and for which the latest boiling start time is earliest.

[0221] Step S25 and step S35 will be described in more detail with reference to FIG. 20. For example, the time at which the processing of step S25 is being performed (the current time) is time t2, illustrated in FIG. 20. In addition, in the schedule illustrated in FIG. 20, the latest boiling start time of first water heater 11a is t11, the latest boiling start time of second water heater 11b is t12, the latest boiling start time of third water heater 11c is t13, and the latest boiling start time of fourth water heater 11d is t14. t11 is a time earlier than t12, t12 is a time earlier than t13, and t13 is a time earlier than t14.

[0222] (a) of FIG. 20 is a diagram illustrating the schedule determined in step S30. The schedule indicated in (b) of FIG. 20 is a diagram illustrating a schedule when it is determined that the demand power will exceed the second reference power. (b) of FIG. 20 is a diagram illustrating a schedule in which the boiling by third water heater 11c, for which the latest boiling start time is the earliest among the plurality of water heaters 11 that have not yet started boiling at time t2 (third and fourth water heaters 11c and 11d), starts earlier. In other words, (b) of FIG. 20 is a diagram illustrating the updated schedule.

[0223] For example, as indicated in (a) of FIG. 20, it is determined that the demand power will exceed the second reference power in the partial time slot at time t2 (the current time). In such a case, in step S35, determiner 130 updates the schedule to start boiling in order from water heater 11, among the plurality of water heaters 11, for which the latest boiling start time is earliest.

[0224] Determiner 130 updates the schedule such that the boiling by third water heater 11c, for which the latest boiling start time is earliest among third and fourth water heaters 11c and 11d, starts earlier, and the boiling by fourth water heater 11d, for which the latest boiling start time is later, starts later. Here, determiner 130 updates the schedule such that the boiling by third water heater 11c starts in the partial time slot. Additionally, to prevent the demand power from exceeding the second reference power in the partial time slot, determiner 130 updates the schedule such that the boiling by fourth water heater 11d starts in the second time slot after the partial time slot.

[0225] Furthermore, controller 140 controls the boiling by the plurality of water heaters 11 in the second time slot including the partial time slot based on the schedule updated by determiner 130 in step S35 (S95a).

[0226] Note that if it is determined that the demand power will not exceed the second reference power in the second time slot (No in S25), controller 140 performs the following processing. In this case, controller 140 controls the boiling by the plurality of water heaters 11 in the second time slot including the partial time slot based on the schedule determined by determiner 130 in step S30 (S95b).

[0227] Operation Example 9 describes operations in which the reference power is changed from the first reference power to the second reference power when the need to conserve power rises sharply due to tight supply and demand of electricity or soaring electricity market prices.

[0228] Then, if determiner 130 determines that the demand power will exceed the second reference power in the partial time slot where the reference power has been changed to the second reference power (Yes in S25), determiner 130 determines the following schedule. Determiner 130 determines a schedule that starts boiling in order from water heater 11 for which the latest boiling start time is the earliest among the plurality of water heaters 11.

[0229] Through this, in Operation Example 9, hot water supply system 100 capable of suppressing the overall demand power (and more specifically, the maximum value of the demand power) of housing complex 40 is realized. For example, as indicated in (b) of FIG. 20, situations where the maximum value of the demand power exceeds the second reference power are suppressed. This makes it less likely that the base rate for housing complex 40 will rise.

[0230] In addition, as described above, the reference power being changed from the first reference power to the second reference power is equivalent to a case where there is demand to conserve power due to tightening in the electricity supply and demand. Even in such a case, hot water supply system 100 can suppress the overall demand power (and more specifically, the maximum value of the demand power) of housing complex 40, and can meet the societal need to conserve electricity.[Operation Example 10]

[0231] FIG. 21 is a flowchart of Operation Example 10 according to the present embodiment.

[0232] Operation Example 10, illustrated in FIG. 21, will describe an example in which the schedule is re-determined such that power is supplied from power supply equipment 23 in the second time slot.

[0233] In Operation Example 10, first, step S30 described in Operation Example 1 is performed, and the schedule is determined.

[0234] Next, based on the schedule determined in step S30 and the first reference power obtained, determiner 130 determines whether the overall demand power of housing complex 40 will exceed the obtained first reference power in the second time slot (S63). In other words, in step S63, it is predicted and determined whether the demand power will still exceed the first reference power even if the start of boiling by third water heater 11c is delayed in step S30 of Operation Example 1.

[0235] Furthermore, if it is determined that the demand power will exceed the first reference power in the second time slot (Yes in S63), determiner 130 re-determines the schedule to supply power from power supply equipment 23 provided in housing complex 40 to housing complex 40 (S73).

[0236] Here, determiner 130 re-determines the schedule to supply power from power supply equipment 23 to housing complex 40 by the amount by which the demand power exceeds the first reference power. The sum of the power supplied by the power company and the power supplied by power supply equipment 23 is equivalent to the demand power. In other words, because the power supplied by the power company is equivalent to the first reference power, situations where the power supplied by the power company exceeds the first reference power are suppressed even if the demand power exceeds the first reference power.

[0237] Furthermore, controller 140 controls the boiling by the plurality of water heaters 11 in the second time slot based on the schedule determined by determiner 130 in step S73 (S90).

[0238] Note that if it is determined that the demand power will not exceed the first reference power in the second time slot (No in S63), controller 140 performs the following processing. In this case, controller 140 controls the boiling by the plurality of water heaters 11 in the second time slot based on the schedule determined by determiner 130 in step S30 (S90).

[0239] In Operation Example 10, if it is determined that the demand power will exceed the first reference power, the schedule is re-determined such that power is supplied from power supply equipment 23 to housing complex 40. Accordingly, situations where the power supplied by the power company exceeds the first reference power are suppressed. This makes it less likely that the electricity rate for housing complex 40 will rise.

[0240] Additionally, in Operation Example 10, if it is determined that the demand power will exceed the first reference power (Yes in S63), determiner 130 re-determines the schedule to supply power from power supply equipment 23 provided in housing complex 40 to housing complex 40, but the configuration is not limited thereto. In this case, for example, determiner 130 may re-determine the schedule to stop electrical equipment 21 (lighting, elevators, and the like) or the like of common area 20. Accordingly, the demand power is reduced, and thus situations where the power supplied by the power company exceeds the first reference power are suppressed.[Operation Example 11]

[0241] FIG. 22 is a flowchart of Operation Example 11 according to the present embodiment.

[0242] Operation Example 11, illustrated in FIG. 22, will describe an example in which the schedule is re-determined such that power is supplied from power supply equipment 23 in the first time slot.

[0243] In Operation Example 11, first, step S30 described in Operation Example 1 is performed, and the schedule is determined.

[0244] Next, determiner 130 determines whether the second expected completion time of boiling by at least one of water heaters 11 falls within the first time slot in the schedule determined in step S30 (S64). Here, the at least one water heater 11 is third water heater 11c for which the start of boiling is delayed in the schedule determined.

[0245] As described above, the second time slot is from 11 PM to 7 AM the next day. In other words, the second expected completion time of the boiling by third water heater 11c, for which the start of the boiling has been delayed, falling within the first time slot means that the second expected completion time falls within the first time slot on the next day (from 7 AM on the next day to 11 PM on the next day).

[0246] Furthermore, if it is determined that the second expected completion time of the boiling by third water heater 11c falls within the first time slot (Yes in S64), determiner 130 re-determines the schedule as follows (S74). In this case, determiner 130 re-determines the schedule to supply power from power supply equipment 23 provided by housing complex 40 for the boiling by third water heater 11c in the first time slot. Here, determiner 130 re-determines the schedule such that all the power required for the boiling by third water heater 11c in the first time slot is supplied from power supply equipment 23. In other words, it is not necessary for power to be supplied from the power company to housing complex 40 for the boiling by third water heater 11c in the first time slot.

[0247] Furthermore, controller 140 controls the boiling by the plurality of water heaters 11 in the second time slot based on the schedule determined by determiner 130 in step S74 (S90).

[0248] Note that if it is determined that the second expected completion time of the boiling by third water heater 11c does not fall within the first time slot (No in S64), controller 140 performs the following processing. In this case, controller 140 controls the boiling by the plurality of water heaters 11 in the second time slot based on the schedule determined by determiner 130 in step S30 (S90).

[0249] In Operation Example 11, if the second expected completion time of the boiling by third water heater 11cs within the first time slot, the schedule is re-determined to supply power from power supply equipment 23 for the boiling. It is therefore not necessary for power to be supplied from the power company to housing complex 40 for the boiling. This makes it possible to keep the electricity rate for housing complex 40 low.[Operation Example 12]

[0250] FIG. 23 is a flowchart of Operation Example 12 according to the present embodiment.

[0251] Operation Example 12, illustrated in FIG. 23, will describe an example in which fifth water heater 11e boils in the first time slot.

[0252] As an example, the processing of Operation Example 12 begins when obtainer 120 obtains, in the first time slot, a boiling instruction for fifth water heater 11e, included in the plurality of water heaters 11, from the owner of fifth water heater 11e. In other words, in Operation Example 12, it is necessary for fifth water heater 11e to boil in the first time slot.

[0253] First, when boiling by fifth water heater 11e is to be performed in the first time slot, determiner 130 determines the lowest price among a first price, a second price, and a third price (S80). The first price, the second price, and the third price will be described here.

[0254] The "first price" refers to a price when the boiling by fifth water heater 11e is performed using power supplied by the power company. In other words, the first price is the price paid to the power company when fifth water heater 11e boils using the power supplied by the power company.

[0255] When the boiling by fifth water heater 11e is performed using power with which charging equipment provided in housing complex 40 was charged (and more specifically, charging equipment included in power supply equipment 23), the price required to recharge the charging equipment is the "second price". In other words, the second price is the price for purchasing power supplied by the power company to recharge the power consumed due to the charging equipment discharging power for fifth water heater 11e to boil.

[0256] When the power required for the boiling by fifth water heater 11e is generated by solar power generation equipment provided in housing complex 40, the selling price of that generated power is the "third price". In other words, if the power required for the boiling by fifth water heater 11e has been generated by the solar power generation equipment, the third price is the price at which that power is sold to the power company, assuming the power is not consumed for boiling.

[0257] Furthermore, if it is determined in step S80 that the first price is lowest among the first price, the second price, and the third price, determiner 130 determines a control signal such that fifth water heater 11e boils using the power supplied by the power company (S81).

[0258] If it is determined in step S80 that the second price is lowest among the first price, the second price, and the third price, determiner 130 determines the control signal such that fifth water heater 11e boils using the power with which the charging equipment has been charged (S82).

[0259] If it is determined in step S80 that the third price is lowest among the first price, the second price, and the third price, determiner 130 determines the control signal such that fifth water heater 11e boils using the power generated by the solar power generation equipment (S83).

[0260] Furthermore, controller 140 controls the boiling by fifth water heater 11e based on the control signals determined by determiner 130 in steps S81, S82 and S83 (S84). More specifically, controller 140 controls communicator 110 to output the determined control signal to control device 13 of fifth individual dwelling 10e. Through this, control device 13 controls the boiling by fifth water heater 11e based on the obtained control signal.

[0261] In Operation Example 12, controller 140 controls the boiling by fifth water heater 11e to ensure the lowest amount of monetary loss. This makes it possible to minimize the monetary loss for the manager of housing complex 40.(Variation 1)

[0262] Variation 1 on the embodiment will be described next. The following descriptions will focus on the differences from the embodiment, and descriptions of common points will be omitted or simplified.

[0263] In the embodiment, hot water supply system 100 is installed in housing complex 40, but the configuration is not limited thereto. In the present variation, hot water supply system 100 is installed in region 340 including housing complex 40.[Configuration]

[0264] FIG. 24 is a block diagram illustrating the functional configuration of hot water supply system 100 according to Variation 1 on the embodiment.

[0265] Hot water supply system 100 is a system installed in region 340 including housing complex 40, a plurality of detached houses 410, and a plurality of facilities 520. Accordingly, FIG. 24 is a block diagram also illustrating functional configuration of each of housing complex 40, the plurality of detached houses 410, and the plurality of facilities 520 included in region 340.

[0266] Hot water supply system 100 suppresses a maximum value of the overall demand power of region 340 by controlling a plurality of water heaters 411 installed in the plurality of detached houses 410 and a plurality of water heaters 11 installed in a plurality of households included in housing complex 40. Note that the plurality of residences according to the present variation include the plurality of detached houses 410 and the plurality of households included in housing complex 40.

[0267] In region 340 according to the present variation, a high-voltage collective power reception contract is selected as the type of contract for supplying power to region 340.

[0268] Hot water supply system 100 according to the present variation determines a schedule for boiling by the plurality of water heaters 411 and the plurality of water heaters 11 before the start of the second time slot, i.e., during the first time slot. Hot water supply system 100 controls the plurality of water heaters 411 and the plurality of water heaters 11 based on the schedule determines.

[0269] Detached house 410 is an example of a residence constructed in region 340. Each of the plurality of detached houses 410 includes water heater 411, electrical equipment 412, control device 413, and power supply equipment 423. Water heater 411, electrical equipment 412, control device 413, and power supply equipment 423 have the same functions as water heater 11, electrical equipment 12, control device 13, and power supply equipment 23 described in the embodiment, respectively.

[0270] Accordingly, control device 413 can perform the same information processing as control device 13. Control device 413 installed in one detached house 410 can output information, such as the hot water supply information about water heater 411 installed in that one detached house 410, to communicator 110. Additionally, control device 413 installed in one detached house 410 can output information, such as power information about electrical equipment 412 installed in that one detached house 410 (equivalent to the individual dwelling power information of the embodiment), to communicator 110.

[0271] Facility 520 is a facility constructed in region 340, and is, for example, a commercial facility, an industrial facility, a school, a public facility, or the like. Each of the plurality of facilities 520 includes electrical equipment 521, power measurement device 522, and power supply equipment 523. Electrical equipment 521, power measurement device 522, and power supply equipment 523 have the same functions as electrical equipment 21, power measurement device 22, and power supply equipment 23 described in the embodiment, respectively.

[0272] Accordingly, power measurement device 522 can perform the same information processing as power measurement device 22. Power measurement device 522 installed in one facility 520 can output information, such as power information about electrical equipment 521 installed in that one facility 520 (equivalent to the common area power information of the embodiment), to communicator 110.

[0273] As a result, hot water supply system 100 according to Variation 1 can also perform Operation Examples 1 to 12 described in the embodiment.(Variation 2)

[0274] Variation 2 on the embodiment will be described next. The following descriptions will focus on the differences from the embodiment, and descriptions of common points will be omitted or simplified.

[0275] In the embodiment, hot water supply system 100 obtains information from control device 13 and power measurement device 22, but the configuration is not limited thereto. In the present variation, hot water supply system 100 obtains information from water heater 11, smart meter 15, power supply equipment 23, and smart meter 25.[Configuration]

[0276] FIG. 25 is a block diagram illustrating the functional configuration of hot water supply system 100 according to Variation 2 on the embodiment.

[0277] In the present variation, each of a plurality of households includes water heater 11 and smart meter 15. Each of the plurality of households does not include control device 13.

[0278] Water heater 11 according to the present variation outputs information, such as the hot water supply information about that water heater 11, to hot water supply system 100.

[0279] Smart meter 15 is a device that can measure the power usage amount by a household every predetermined time period (e.g., 30 minutes), and has a communication function. In other words, smart meter 15 can measure the power used by electrical equipment 12 (not shown), and can output the individual dwelling power information to hot water supply system 100.

[0280] In the present variation, smart meter 25 and power supply equipment 23 are installed in common area 20. Power measurement device 22 is not installed in common area 20.

[0281] Power supply equipment 23 according to the present variation outputs power supply equipment information, indicating a power generation amount, a charging amount, and the like by power supply equipment 23, to hot water supply system 100.

[0282] Smart meter 25 is a device that can measure the power usage amount by common area 20 every predetermined time period (e.g., 30 minutes), and has a communication function. In other words, smart meter 25 can measure the power used by electrical equipment 21 (not shown), and can output the common area power information to hot water supply system 100.

[0283] As a result, hot water supply system 100 according to Variation 2 can also perform Operation Examples 1 to 12 described in the embodiment.(Variation 3)

[0284] Variation 3 on the embodiment will be described next. The following descriptions will focus on the differences from Variations 1 and 2, and descriptions of common points will be omitted or simplified.[Configuration]

[0285] FIG. 26 is a block diagram illustrating the functional configuration of hot water supply system 100 according to Variation 3 on the embodiment.

[0286] In Variation 1, hot water supply system 100 obtains information from control devices 13 and 413 and power measurement devices 22 and 522, but the configuration is not limited thereto. In the present variation, hot water supply system 100 obtains information from water heaters 11 and 411, smart meters 15, 25, 415, and 525, and power supply equipment 23, 423, and 523.

[0287] Hot water supply system 100 according to Variation 3 can therefore also perform Operation Examples 1 to 12 described in the embodiment.(Effects, Etc.)

[0288] Invention 1 is hot water supply system 100, including: obtainer 120 that obtains a plurality of items of hot water supply information, each including a boiling amount of water heater 11 and a usage start time of water heater 11, and a first reference power of a plurality of residences in which a plurality of water heaters 11 are respectively installed, each of the plurality of water heaters 11 being water heater 11; determiner 130 that, based on the boiling amount included in each of the plurality of items of hot water supply information obtained, determines a schedule for starting boiling in order from water heater 11, among the plurality of water heaters 11, for which a latest boiling start time is earliest, when starting boiling by the plurality of water heaters 11 simultaneously is determined to cause an overall demand power of the plurality of residences to exceed the first reference power obtained, the latest boiling start time being a latest time to start boiling to ensure hot water does not run out at the usage start time included in the hot water supply information for that water heater 11; and controller 140 that controls boiling by the plurality of water heaters 11 based on the schedule determined.

[0289] Through this, as described in Operation Example 1, hot water supply system 100 capable of suppressing the overall demand power (and more specifically, the maximum value of the demand power) of a plurality of residences (housing complex 40, in Operation Example 1) is realized. For example, as indicated in (b) of FIG. 3, situations where the maximum value of the demand power exceeds the first reference power are suppressed. This makes it less likely that the base rate for housing complex 40 will rise.

[0290] Invention 2 is hot water supply system 100 according to Invention 1, wherein among a first time slot and a second time slot in which a power unit price is lower than in the first time slot, obtainer 120 obtains the first reference power in the second time slot; determiner 130 determines, before the second time slot, the schedule for starting the boiling in order from water heater 11 for which the latest boiling start time is earliest, when starting boiling by the plurality of water heaters 11 simultaneously in the second time slot is determined to cause the overall demand power of the plurality of residences to exceed the first reference power obtained; and controller 140 controls boiling by the plurality of water heaters 11 in the second time slot based on the schedule determined.

[0291] Through this, as described in Operation Example 1, the boiling by the plurality of water heaters 11 is performed in the second time slot in which the power unit price is lower, which makes it possible to reduce the electricity rate paid by the owners of water heaters 11. In other words, hot water supply system 100 capable of reducing the electricity rate paid by the owners of water heaters 11 is realized.

[0292] Invention 3 is hot water supply system 100 according to Invention 1 or 2, wherein when the plurality of water heaters 11 include two water heaters 11 for which the latest boiling start time is a same time, determiner 130 determines the schedule to start boiling in order from water heater 11, among the two water heaters 11, for which the boiling amount included in the hot water supply information for that water heater 11 is higher.

[0293] Through this, as described in Operation Example 1, the schedule is determined such that boiling by water heater 11 having a high boiling amount (e.g., third water heater 11c) is performed preferentially, which makes it less likely that water heater 11 will run out of hot water. In other words, hot water supply system 100 that makes it difficult for hot water heaters 11 to run out of hot water is realized.

[0294] Invention 4 is hot water supply system 100 according to Invention 2, wherein obtainer 120 obtains a first power unit price for the first time slot and a second power unit price for the second time slot, and based on the first power unit price and the second power unit price obtained, determiner 130 determines the schedule to reduce an electricity rate resulting from the boiling by each of the plurality of water heaters 11.

[0295] Through this, as described in Operation Example 2, the boiling by water heater 11 (e.g., first water heater 11a) is performed during a time slot in which the power unit price is lower, which makes it possible to reduce the electricity rate paid by the owner of water heater 11. In other words, hot water supply system 100 capable of reducing the electricity rate paid by the owners of water heaters 11 is realized.

[0296] Invention 5 is hot water supply system 100 according to Invention 4, wherein when a plurality of second time slots, each being the second time slot, are provided in one day, based on the first power unit price and the second power unit price obtained, and the usage start time included in each of the plurality of items of hot water supply information obtained, determiner 130 determines the schedule to reduce the electricity rate resulting from the boiling by each of the plurality of water heaters 11, and to shorten a time difference between a first expected completion time and the usage start time, the first expected completion time being a time at which the boiling by each of the plurality of water heaters 11 is expected to be completed.

[0297] Through this, as described in Operation Example 3, the boiling by water heater 11 (e.g., first water heater 11a) is performed during a time slot in which the power unit price is lower, which makes it possible to reduce the electricity rate paid by the owner of water heater 11. Incidentally, as indicated in (a) of FIG. 9, if the time from the first expected completion time to the usage start time is long, a problem arises in that the boiled water cools down. However, in Operation Example 3, as indicated in (b) of FIG. 9, the time difference between the first expected completion time and the usage start time is short, which makes it unlikely that the stated problem will arise. In other words, hot water supply system 100 that can reduce the electricity rate paid by the owners of water heaters 11, and that makes it less likely that a problem in which the boiled water cools down will occur, is realized.

[0298] Invention 6 is hot water supply system 100 according to any one of Inventions 1 to 5, wherein when controller 140 is controlling boiling by the plurality of water heaters 11 based on the schedule determined, when the overall demand power of the plurality of residences is determined to exceed the first reference power obtained, determiner 130 updates the schedule to stop boiling by water heater 11, among the plurality of water heaters 11, for which a time difference between a second expected completion time and a third expected completion time is greatest, the second expected completion time being a time at which boiling indicated by the schedule determined is expected to be completed, and the third expected completion time being a time at which boiling is expected to be completed when the boiling is started at the latest boiling start time; and controller 140 controls boiling by the plurality of water heaters 11 based on the schedule updated.

[0299] Through this, as described in Operation Example 4, the schedule is updated such that hot water supply system 100 stops the boiling by water heater 11 (second water heater 11b) when the demand power exceeds the first reference power. Accordingly, situations where the demand power exceeds the first reference power are suppressed. In other words, hot water supply system 100 capable of suppressing the overall demand power (and more specifically, the maximum value of the demand power) of a plurality of residences (housing complex 40, in Operation Example 4) is realized. Additionally, having determiner 130 update the schedule to stop the boiling by water heater 11 for which the time difference between the second expected completion time and the third expected completion time is large makes it less likely that water heater 11 for which the time difference is small and water heater 11 for which the time difference is large will run out of hot water.

[0300] Invention 7 is hot water supply system 100 according to any one of Inventions 1 to 6, wherein when controller 140 is causing two or more water heaters 11 among the plurality of water heaters 11 to boil according to the schedule determined, obtainer 120 obtains a boiling instruction instructing boiling by other water heater 11, among the plurality of water heaters 11, aside from the two or more water heaters 11; determiner 130 updates the schedule to start the boiling by other water heater 11 based on the boiling instruction obtained; and controller 140 controls boiling by the plurality of water heaters 11 based on the schedule updated.

[0301] Through this, as described in Operation Example 5, hot water supply system 100 performs the following processing when the boiling instruction for other water heater 11 (third water heater 11c) is obtained. That is, hot water supply system 100 updates the schedule to start the boiling by other water heater 11. Through this, hot water supply system 100 can perform the boiling by other water heater 11.

[0302] Invention 8 is hot water supply system 100 according to Invention 7, wherein when an information processing device accepts an operation from an owner of other water heater 11, the information processing device outputs the boiling instruction, the boiling instruction being indicated by the operation accepted, and obtainer 120 obtains the boiling instruction output.

[0303] Through this, as described in Operation Example 5, hot water supply system 100 can update the schedule in response to an operation made by the owner.

[0304] Invention 9 is hot water supply system 100 according to Invention 7 or 8, wherein based on the boiling instruction obtained, when the overall demand power of the plurality of residences is determined to exceed the first reference power obtained, determiner 130 updates the schedule to stop boiling by water heater 11, among the two or more water heaters 11, for which a time difference between a second expected completion time and a third expected completion time is greatest, and to start the boiling by other water heater 11, the second expected completion time being a time at which boiling indicated by the schedule determined is expected to be completed, and the third expected completion time being a time at which boiling is expected to be completed when boiling is started at the latest boiling start time.

[0305] Through this, as described in Operation Example 5, hot water supply system 100 performs the following processing when the demand power is determined to exceed the first reference power based on the boiling instruction for other water heater 11 (third water heater 11c). That is, hot water supply system 100 suppresses situations where the demand power exceeds the first reference power by updating the schedule to stop the boiling by water heater 11 (second water heater 11b). In other words, hot water supply system 100 capable of suppressing the overall demand power (and more specifically, the maximum value of the demand power) of a plurality of residences (housing complex 40, in Operation Example 5) is realized. Furthermore, determiner 130 updates the schedule to stop the boiling by water heater 11 for which the time difference between the second expected completion time and the third expected completion time is large (second water heater 11b). Through this, it becomes less likely that water heater 11 for which the time difference is small and water heater 11 for which the time difference is large will run out of hot water. In other words, hot water supply system 100 that makes it difficult to run out of hot water is realized.

[0306] Invention 10 is hot water supply system 100 according to Invention 2, wherein based on the usage start time included in each of the plurality of items of hot water supply information obtained, when, among the plurality of water heaters 11, a first target water heater for which a time from a second expected completion time to the usage start time exceeds a reference time is determined to be present, the second expected completion time being a time at which boiling indicated by the schedule determined is expected to be completed, determiner 130 re-determines the schedule to pause and then re-perform boiling by the first target water heater after the boiling by the first target water heater is performed in the second time slot, and complete the boiling by the first target water heater by the usage start time.

[0307] Through this, as described in Operation Example 6, the schedule is re-determined by determiner 130 to temporarily stop the boiling by the first target water heater after the boiling by the first target water heater, start the boiling again, and complete the boiling by the first target water heater by the usage start time. Note that determiner 130 re-determines the schedule such that the time from the time when the boiling by the first target water heater is completed to the expected usage time drops below the reference time due to the boiling being performed again. Accordingly, the time from the time when the boiling by the first target water heater is completed to the expected usage time is sufficiently shortened, and the problem that the boiled water cools down therefore becomes unlikely to occur. In other words, hot water supply system 100 that makes it difficult for the stated problem to occur is realized.

[0308] Invention 11 is hot water supply system 100 according to any one of Inventions 1 to 10, wherein when the plurality of water heaters 11 include a second target water heater for which a boiling number indicated by the schedule determined is at least a predetermined number, determiner 130 re-determines the schedule to bring the boiling number of the second target water heater to less than the predetermined number.

[0309] Through this, as described in Operation Example 7, the boiling number of the second target water heater is less than the predetermined number, and thus a problem that the amount of power consumed by water heater 11 increases due to the number of boiling times being high is unlikely to occur. In other words, the amount of consumed power is suppressed, and thus hot water supply system 100 can suppress the overall demand power (and more specifically, the maximum value of the demand power) of housing complex 40.

[0310] Invention 12 is hot water supply system 100 according to Invention 2, wherein when controller 140 is controlling boiling by the plurality of water heaters 11 in accordance with the schedule determined, obtainer 120 obtains a second reference power for the plurality of residences, the second reference power being a reference power lower than the first reference power and for a partial time slot included in the second time slot; when the overall demand power of the plurality of residences is determined to exceed the second reference power obtained in the partial time slot in the schedule determined, determiner 130 updates the schedule to start boiling in order from water heater 11, among the plurality of water heaters 11, for which the latest boiling start time is earliest; and controller 140 controls boiling by the plurality of water heaters 11 in the partial time slot based on the schedule updated.

[0311] Through this, as described in Operation Example 9, hot water supply system 100 capable of suppressing the overall demand power (and more specifically, the maximum value of the demand power) of a plurality of residences (housing complex 40, in Operation Example 9) is realized. For example, as indicated in (b) of FIG. 20, situations where the maximum value of the demand power exceeds the second reference power are suppressed. This makes it less likely that the base rate for housing complex 40 will rise.

[0312] Invention 13 is a hot water supply method executed by hot water supply system 100, the hot water supply method including: obtaining a plurality of items of hot water supply information, each including a boiling amount of water heater 11 and a usage start time of water heater 11, and a first reference power of a plurality of residences in which a plurality of water heaters 11 are respectively installed, each of the plurality of water heaters 11 being water heater 11; determining, based on the boiling amount included in each of the plurality of items of the hot water supply information obtained, a schedule for starting boiling in order from water heater 11, among the plurality of water heaters 11, for which a latest boiling start time is earliest, when starting boiling by the plurality of water heaters 11 simultaneously is determined to cause an overall demand power of the plurality of residences to exceed the first reference power obtained, the latest boiling start time being a latest time to start boiling to ensure hot water does not run out at the usage start time included in the hot water supply information for that water heater 11; and controlling boiling by the plurality of water heaters 11 based on the schedule determined.

[0313] Through this, as described in Operation Example 1, a hot water supply method capable of suppressing the overall demand power (and more specifically, the maximum value of the demand power) of a plurality of residences (housing complex 40, in Operation Example 1) is realized. For example, as indicated in (b) of FIG. 3, situations where the maximum value of the demand power exceeds the first reference power are suppressed. This makes it less likely that the base rate for housing complex 40 will rise.(Other Embodiments)

[0314] Although an embodiment has been described thus far, the present invention is not limited to the foregoing embodiment and variations.

[0315] Note that the first time slot was described as being from 7 AM to 11 PM, and the second time slot as being from 11 PM to 7 AM the next day, as an example, but the time slots are not limited thereto.

[0316] In addition, although the boiling amount was determined by control device 13, the configuration is not limited thereto. For example, hot water supply system 100 may calculate the boiling amount from the target boiling amount and the remaining hot water amount in the storage tank.

[0317] To determine the boiling amount and the usage start time, a period from the day before the one day back to one week prior thereto was used as the past predetermined period, but the configuration is not limited thereto. For example, a period of one week before and after the day one year previous to the stated day may be used as the predetermined period in the past.

[0318] Additionally, the method through which the devices communicate with each other described in the foregoing embodiment and variations is merely one example. The method through which the devices communicate with each other is not particularly limited.

[0319] In the foregoing embodiment and variations, the used power (consumed power) required for the boiling by water heater 11 was proportional to the boiling amount of that water heater 11, but the configuration is not limited thereto.

[0320] For example, hot water supply system 100 may calculate the used power required for the boiling by water heater 11 and the time required for the boiling based on the specifications (specs) of each of the plurality of water heaters 11, the region where the plurality of water heaters 11 are installed, the season at the present time, and the like. Hot water supply system 100 performs this calculation such that, for example, if the area where the plurality of water heaters 11 are installed is a colder region, the used power required for the boiling by water heater 11 is greater, and the time required for the boiling by water heater 11 is longer. In addition, hot water supply system 100 performs the calculation such that, if the current season is winter, the used power required for the boiling by water heater 11 is greater, and the time required for the boiling by water heater 11 is longer. Additionally, for example, if hot water supply system 100 cannot obtain information indicating the season at the present time, hot water supply system 100 may obtain data including the temperature and the water temperature at the present time (data from the Meteorological Agency or the like), and calculate the used power required for the boiling by water heater 11 and the time required for the boiling based on that data.

[0321] Additionally, for example, hot water supply system 100 may obtain data including historical temperatures and water temperatures (data from the Meteorological Agency or the like), and calculate the used power required for the boiling by water heater 11 and the time required for the boiling based on that data.

[0322] Additionally, if the overall demand power of the plurality of residences is determined to exceed the first reference power, the following processing may be performed. For example, communicator 110 of hot water supply system 100 according to the embodiment sends information (a message) requesting cooperation with power conservation to control device 13 of each of the plurality of individual dwellings 10 or the information terminals (e.g., smartphones) owned by the owners. The owners of individual dwellings 10 can therefore be expected to cooperate with power conservation. A display of hot water supply system 100 displays the difference in the rates (the amount by which the rate is reduced) when the demand power does not exceed the first reference power compared to when the demand power exceeds the first reference power. The manager of hot water supply system 100 can make the owners who cooperate with power conservation more amenable to such cooperation by paying the displayed rate reduction to those owners.

[0323] Note that it is preferable to notify the owner of the reduction in the stated rate before the information (message) requesting cooperation with power conservation is sent. For example, information indicating the stated reduction in the rate may be output from communicator 110 of hot water supply system 100 to control device 13 of each of the plurality of individual dwellings 10 or the information terminals (e.g., smartphones) owned by the owners. This enables the owners to see the financial benefits of cooperating with power conservation.

[0324] In addition, there are cases where it is clear in advance (e.g., one hour or one week in advance) that the overall demand power of the plurality of residences will exceed the first reference power in a given time slot.

[0325] As an example, in this case, it is preferable to send the information (message) requesting cooperation with power conservation before the given time slot (e.g., the day before or several hours before the given time slot). This gives the owner time to consider whether to cooperate with power conservation before the start of the given time slot.

[0326] As another example, in this case, the power unit price for the given time slot may be raised. In other words, a higher power unit price is used than the power unit price used when the overall demand power of the plurality of residences does not exceed the first reference power in the given time slot. Hot water supply system 100 performs the processing of the foregoing operation examples using the power unit price raised in this manner.

[0327] In addition, the manager of hot water supply system 100 may obtain information on cooperation with power conservation by a plurality of owners by conducting a questionnaire on such cooperation with the owners of first to fifth individual dwellings 10a to 10e. By controlling an information terminal such as a smartphone, a tablet, or a personal computer, the manager sends information about the cooperation with power conservation to communicator 110 of hot water supply system 100. Obtainer 120 of hot water supply system 100 obtains a plurality of items of information on cooperation with power conservation, obtained by communicator 110. The questionnaire asks whether the owner can cooperate with power conservation in individual dwelling 10 they own when the overall demand power of the plurality of residences exceeds the first reference power obtained, and the results of the questionnaire are reflected in the information on the cooperation with power conservation. Based on the plurality of items of information about cooperation with power conservation obtained, hot water supply system 100 determines equipment (water heaters 11 and electrical equipment 21) to stop when the overall demand power of the plurality of residences exceeds the first reference power obtained. Hot water supply system 100 determines a schedule to stop the determined equipment, and controls the equipment based on the schedule determined. For example, if the information on cooperation with power conservation indicates that such cooperation is not possible in all of first to fifth individual dwellings 10a to 10e, hot water supply system 100 determines a schedule to stop electrical equipment 21 installed in common area 20.

[0328] Processing executed by a specific processor in the foregoing embodiment and variations may be executed by a different processor. Additionally, the order of multiple processes may be changed, and multiple processes may be executed in parallel.

[0329] Additionally, in the foregoing embodiment and variation, the constituent elements such as obtainer 120, determiner 130, controller 140, and the like may be implemented by executing software programs corresponding to those constituent elements. Each constituent element may be realized by a program executor such as a CPU or a processor reading out and executing a software program recorded into a recording medium such as a hard disk or semiconductor memory.

[0330] Constituent elements such as obtainer 120, determiner 130, controller 140, and the like may be implemented by hardware. For example, constituent elements such as controller 140 may be circuitry (or integrated circuitry). This circuitry may constitute a single overall circuit, or may be separate circuits. The circuitry may be generic circuitry, or may be dedicated circuitry.

[0331] The general or specific aspects of the present invention may be implemented by a system, a device, a method, an integrated circuit, a computer program, or a computer-readable recording medium such as a CD-ROM. These forms may also be implemented by any desired combination of systems, devices, methods, integrated circuits, computer programs, and recording media. For example, the present invention may be realized as hot water supply system 100 according to the foregoing embodiment and variations, or as a hot water supply method executed by hot water supply system 100. The present invention may be implemented as a program for causing a computer to execute such a hot water supply method, or as a non-transitory recording medium having such a program recorded thereon. Such a program includes an application program for causing a computer, such as a general-purpose information terminal or the like, to function as hot water supply system 100 according to the foregoing embodiment and variations.

[0332] Note that embodiments resulting from variations on the above embodiment and variations arrived at by those skilled in the art, as well as embodiments resulting from optional combinations of elements and functions in the above embodiment and variations are included within the present invention as long as the embodiments do not depart from the scope of the present invention.[Reference Signs List]

[0333] 11, 411 Water heater 100 Hot water supply system 120 Obtainer 130 Determiner 140 Controller

Examples

embodiment

[Embodiment]

[Configuration]

[0014]The configuration of hot water supply system 100 according to the present embodiment will be described.

[0015]FIG. 1A is a block diagram illustrating the functional configuration of hot water supply system 100 according to the present embodiment.

[0016]Hot water supply system 100 is a system installed in housing complex 40. Accordingly, FIG. 1A is a block diagram also illustrating functional configurations of housing complex 40 aside from hot water supply system 100. Hot water supply system 100 suppresses a maximum value of the overall demand power of housing complex 40 by controlling a plurality of water heaters 11 installed in a plurality of residences included in housing complex 40.

[0017]In housing complex 40 according to the present embodiment, a high-voltage collective power reception contract is selected as the type of contract for supplying power to housing complex 40. In this contract, two types of time slots having different power unit prices ...

example 1

[Operation Example 1]

[0051]FIG. 2 is a flowchart of Operation Example 1 according to the present embodiment.

[0052]As illustrated in FIG. 2, steps S10, S20, S30, and S40 are processing performed in the first time slot, and step S90 is processing performed in the second time slot. Note that the time slot in which a step is performed may be indicated in the flowcharts in subsequent figures as well.

[0053]Although the present operation example describes an example in which the schedule is determined in the first time slot and the boiling by the plurality of water heaters 11 is performed in the second time slot, the configuration is not limited thereto. As described above, hot water supply system 100 may determine a schedule for boiling by the plurality of water heaters 11 before the boiling by the plurality of water heaters 11 starts, and control the boiling by the plurality of water heaters 11 based on the schedule determined. Accordingly, for example, the schedule may be determined in ...

example 2

[Operation Example 2]

[0095]FIG. 6 is a flowchart of Operation Example 2 according to the present embodiment. FIG. 7 is a diagram illustrating a schedule of Operation Example 2 according to the present embodiment.

[0096]Operation Example 2 will describe an example in which three types of time slots having different power unit prices (first to third time slots) are provided, and a schedule for boiling by one water heater 11 (here, first water heater 11a) is determined.

[0097]As illustrated in FIG. 6, the processing of step S10 is performed first, in the same manner as in FIG. 2.

[0098] Then, obtainer 120 obtains the first power unit price for the first time slot and the second power unit price for the second time slot. More specifically, obtainer 120 obtains the first power unit price for the first time slot, the second power unit price for the second time slot, and the third power unit price for the third time slot (S11). Obtainer 120 obtains the first power unit price, the second power...

Claims

1. A hot water supply system comprising: an obtainer that obtains a plurality of items of hot water supply information, each including a boiling amount of a water heater and a usage start time of the water heater, and a first reference power of a plurality of residences in which a plurality of water heaters are respectively installed, each of the plurality of water heaters being the water heater; a determiner that, based on the boiling amount included in each of the plurality of items of the hot water supply information obtained, determines a schedule for starting boiling in order from a water heater, among the plurality of water heaters, for which a latest boiling start time is earliest, when starting boiling by the plurality of water heaters simultaneously is determined to cause an overall demand power of the plurality of residences to exceed the first reference power obtained, the latest boiling start time being a latest time to start boiling to ensure hot water does not run out at the usage start time included in the hot water supply information for that water heater; and a controller that controls boiling by the plurality of water heaters based on the schedule determined.

2. The hot water supply system according to claim 1, wherein among a first time slot and a second time slot in which a power unit price is lower than in the first time slot, the obtainer obtains the first reference power in the second time slot, the determiner determines, before the second time slot, the schedule for starting the boiling in order from the water heater for which the latest boiling start time is earliest, when starting boiling by the plurality of water heaters simultaneously in the second time slot is determined to cause the overall demand power of the plurality of residences to exceed the first reference power obtained, and the controller controls boiling by the plurality of water heaters in the second time slot based on the schedule determined.

3. The hot water supply system according to claim 1, wherein when the plurality of water heaters include two water heaters for which the latest boiling start time is a same time, the determiner determines the schedule to start boiling in order from a water heater, among the two water heaters, for which the boiling amount included in the hot water supply information for that water heater is higher.

4. The hot water supply system according to claim 2, wherein the obtainer obtains a first power unit price for the first time slot and a second power unit price for the second time slot, and based on the first power unit price and the second power unit price obtained, the determiner determines the schedule to reduce an electricity rate resulting from the boiling by each of the plurality of water heaters.

5. The hot water supply system according to claim 4, wherein when a plurality of second time slots, each being the second time slot, are provided in one day, based on the first power unit price and the second power unit price obtained, and the usage start time included in each of the plurality of items of hot water supply information obtained, the determiner determines the schedule to reduce the electricity rate resulting from the boiling by each of the plurality of water heaters, and to shorten a time difference between a first expected completion time and the usage start time, the first expected completion time being a time at which the boiling by each of the plurality of water heaters is expected to be completed.

6. The hot water supply system according to claim 1, wherein when the controller is controlling boiling by the plurality of water heaters based on the schedule determined, when the overall demand power of the plurality of residences is determined to exceed the first reference power obtained, the determiner updates the schedule to stop boiling by a water heater, among the plurality of water heaters, for which a time difference between a second expected completion time and a third expected completion time is greatest, the second expected completion time being a time at which boiling indicated by the schedule determined is expected to be completed, and the third expected completion time being a time at which boiling is expected to be completed when the boiling is started at the latest boiling start time, and the controller controls boiling by the plurality of water heaters based on the schedule updated.

7. The hot water supply system according to claim 1, wherein when the controller is causing two or more water heaters among the plurality of water heaters to boil according to the schedule determined, the obtainer obtains a boiling instruction instructing boiling by an other water heater, among the plurality of water heaters, aside from the two or more water heaters, the determiner updates the schedule to start the boiling by the other water heater based on the boiling instruction obtained, and the controller controls boiling by the plurality of water heaters based on the schedule updated.

8. The hot water supply system according to claim 7, wherein when an information processing device accepts an operation from an owner of the other water heater, the information processing device outputs the boiling instruction, the boiling instruction being indicated by the operation accepted, and the obtainer obtains the boiling instruction output.

9. The hot water supply system according to claim 7 or 8, wherein based on the boiling instruction obtained, when the overall demand power of the plurality of residences is determined to exceed the first reference power obtained, the determiner updates the schedule to stop boiling by a water heater, among the two or more water heaters, for which a time difference between a second expected completion time and a third expected completion time is greatest, and to start the boiling by the other water heater, the second expected completion time being a time at which boiling indicated by the schedule determined is expected to be completed, and the third expected completion time being a time at which boiling is expected to be completed when boiling is started at the latest boiling start time.

10. The hot water supply system according to claim 2, wherein based on the usage start time included in each of the plurality of items of hot water supply information obtained, when, among the plurality of water heaters, a first target water heater for which a time from a second expected completion time to the usage start time exceeds a reference time is determined to be present, the second expected completion time being a time at which boiling indicated by the schedule determined is expected to be completed, the determiner re-determines the schedule to pause and then re-perform boiling by the first target water heater after the boiling by the first target water heater is performed in the second time slot, and complete the boiling by the first target water heater by the usage start time.

11. The hot water supply system according to claim 1, wherein when the plurality of water heaters include a second target water heater for which a boiling number indicated by the schedule determined is at least a predetermined number, the determiner re-determines the schedule to bring the boiling number of the second target water heater to less than the predetermined number.

12. The hot water supply system according to claim 2, wherein when the controller is controlling boiling by the plurality of water heaters in accordance with the schedule determined, the obtainer obtains a second reference power for the plurality of residences, the second reference power being a reference power lower than the first reference power and for a partial time slot included in the second time slot, when the overall demand power of the plurality of residences is determined to exceed the second reference power obtained in the partial time slot in the schedule determined, the determiner updates the schedule to start boiling in order from a water heater, among the plurality of water heaters, for which the latest boiling start time is earliest, and the controller controls boiling by the plurality of water heaters in the partial time slot based on the schedule updated.

13. A hot water supply method executed by a hot water supply system, the hot water supply method comprising: obtaining a plurality of items of hot water supply information, each including a boiling amount of a water heater and a usage start time of the water heater, and a first reference power of a plurality of residences in which a plurality of water heaters are respectively installed, each of the plurality of water heaters being the water heater; determining, based on the boiling amount included in each of the plurality of items of the hot water supply information obtained, a schedule for starting boiling in order from a water heater, among the plurality of water heaters, for which a latest boiling start time is earliest, when starting boiling by the plurality of water heaters simultaneously is determined to cause an overall demand power of the plurality of residences to exceed the first reference power obtained, the latest boiling start time being a latest time to start boiling to ensure hot water does not run out at the usage start time included in the hot water supply information for that water heater; and controlling boiling by the plurality of water heaters based on the schedule determined.

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