Storage tank type hot water supply device

Abstract

To provide a hot water storage type water heater which can use power generated by a photovoltaic system for boiling while reflecting a desire of each user.SOLUTION: A hot water storage type water heater comprises: a heat pump unit operated by self-generated power generated by a photovoltaic system, and commercial power, and boils hot water; a weather prediction information acquisition part for acquiring weather prediction information of a prescribed time band; an execution determination part for determining whether or not the boiling by the self-generated power should be executed in the prescribed time band on the basis of a predicted power generation amount of the self-generated power calculated on the basis of the weather prediction information; and a mode acquisition part for acquiring information related to a mode selected by a user out of a first mode and a second mode. In order to facilitate determination to execute the boiling by the self-generated power when the second mode is selected, the execution determination part makes calculation methods of the prediction power generation amount differ from each other in the case that the first mode is selected, and in the case that the second mode is selected.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a storage type hot water supply device that boils water using electricity generated by a solar power generation system. [Background technology]

[0002] Conventionally, there is known a technology that uses a Home Energy Management System (HEMS) to centrally manage the energy used in a home. For example, there is known a technology that predicts a time period when the HEMS can generate enough power to perform a water heating operation so that a storage-type hot water heater linked to a solar power generation system can efficiently heat water using the power generated by the solar power generation system. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-115826 A Summary of the Invention [Problem to be solved by the invention]

[0004] Although the introduction of a HEMS offers many benefits, it also has disadvantages, such as the introduction costs and construction work required for the introduction, making it difficult to introduce a HEMS in some cases. Even in such cases, there is a need for a method to link existing equipment and use the electricity generated by the solar power generation system to heat water efficiently while reflecting the wishes of each user.

[0005] The present invention has been made in consideration of these circumstances, and aims to provide a storage type hot water supply device that can use the electricity generated by a solar power generation system for heating water while reflecting the wishes of each user. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, the storage type hot water supply device of the present invention comprises a hot water storage tank for storing hot water, a heat pump unit that operates on self-generated power generated by a solar power generation system and commercial power supplied from a commercial power source and boils the hot water, a weather forecast information acquisition unit that acquires weather forecast information for a specified time period, an execution determination unit that determines whether or not to operate the heat pump unit with the self-generated power during the specified time period to boil the hot water using self-generated power, based on a predicted power generation amount of the self-generated power calculated based on the weather forecast information acquisition unit, and a mode acquisition unit that acquires information regarding a mode selected by a user from a first mode and a second mode which are modes related to the judgment of the execution determination unit, and the execution determination unit calculates the predicted power generation amount in a different way when the first mode is selected and when the second mode is selected, so that it is more likely to determine that boiling using the self-generated power will be performed when the second mode is selected than when the first mode is selected. Among the specified time periods in which it is determined that boiling will be performed using the self-generated electricity, the time period that is consecutively obtained for the time required to boil the water using the self-generated electricity and that is the earliest time period relative to the timing at which the weather forecast information was obtained is determined to be the start time of boiling the water using the self-generated electricity. Effect of the Invention

[0007] In the storage type hot water supply device according to the present invention, the electricity generated by the solar power generation system can be used for boiling water while reflecting the wishes of each user. [Brief description of the drawings]

[0008] [Figure 1] 1 is a system configuration diagram of a hot water supply system including a storage type hot water supply device in this embodiment. [Diagram 2] FIG. 2 is a functional block diagram of the control unit and the server. [Diagram 3] 11 is a flowchart illustrating a daytime boiling determination process executed by the control unit. [Figure 4] A conceptual diagram of the processing executed in the water heating device when it is determined in the daytime heating determination process that daytime heating is impossible. [Diagram 5] 13 is a conceptual diagram of the process executed in the water heating device when it is determined in the daytime boiling determination process that daytime boiling is possible. FIG. [Figure 6]FIG. 13 is an explanatory diagram conceptually showing information required to execute the daytime boiling determination process when the standard mode is selected. [Figure 7] FIG. 13 is an explanatory diagram conceptually showing information required to execute the daytime boiling determination process when the active mode is selected. [Figure 8] FIG. 13 is a diagram showing an example of a screen display when information required to perform the daytime boiling determination process is received from a user on a user terminal. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] BEST MODE FOR CARRYING OUT THE DISCLOSURE A hot water storage type hot water supply device 1 according to an embodiment of the present invention will be described with reference to the accompanying drawings.

[0010] FIG. 1 is a system configuration diagram of a hot water supply system 100 including a storage type hot water supply device 1 in this embodiment.

[0011] The hot water supply system 100 includes a distribution board 2, a solar power generation system 3, a server 6, and a storage type hot water supply apparatus 1 (hereinafter simply referred to as "hot water supply apparatus 1").

[0012] The distribution board 2 is installed in a building such as a house (hereinafter simply referred to as a "house") together with the solar power generation system 3 and the hot water heater 1. The distribution board 2 is connected to a commercial power source 2a and the solar power generation system 3. The distribution board 2 supplies commercial power supplied from the commercial power source 2a and privately generated power generated by the solar power generation system 3 to the hot water heater 1 used in the house and to electrical load devices in the house other than the hot water heater 1, such as an air conditioner (hereinafter simply referred to as "air conditioner, etc. 7" in the following explanation and in FIG. 1).

[0013] The solar power generation system 3 includes a solar power generation panel 4 and an inverter 5. The solar power generation panel 4 is installed on the roof of a house or the like. The inverter 5 converts the power generated by the solar power generation panel 4 into AC power.

[0014] Server 6 is connected to water heating apparatus 1 and user terminal 9 via network 8. Server 6 transmits and receives information (details will be described later) necessary for various processes executed by water heating apparatus 1 to and from water heating apparatus 1 and user terminal 9. User terminal 9 is a device owned by the user of water heating apparatus 1 that is capable of communicating with server 6 via network 8, such as a smartphone, tablet, or personal computer.

[0015] The hot water supply device 1 includes a hot water tank 10, a heat pump unit 19, a circulation circuit 27, a remote control 32, and a control unit 31.

[0016] The hot water tank 10 stores hot water to be supplied to hot water supply terminals such as a bath, a kitchen, etc. The hot water tank 10 has a water supply pipe 11, a hot water outlet pipe 12, a water supply bypass pipe 13, a hot water supply pipe 15, and a hot water temperature sensor 18.

[0017] The water supply pipe 11 is connected to the bottom of the hot water storage tank 10 and supplies water to the hot water storage tank 10. The hot water outlet pipe 12 is connected to the top of the hot water storage tank 10 and outlets hot water from the hot water storage tank 10. The water supply bypass pipe 13 is a pipe branched off from the water supply pipe 11 and is connected to the hot water outlet pipe 12 via a mixing valve 14. The mixing valve 14 mixes the hot water from the hot water outlet pipe 12 and the water from the water supply bypass pipe 13 to a hot water supply temperature set by the remote control 32.

[0018] The hot water supply pipe 15 supplies hot water supplied via the mixing valve 14 to the hot water supply terminal. The hot water supply pipe 15 has a hot water supply flow rate sensor 16 and a hot water supply temperature sensor 17. The hot water supply flow rate sensor 16 detects the hot water supply flow rate and outputs a corresponding detection signal to the control unit 31. The hot water supply temperature sensor 17 detects the hot water supply temperature and outputs a corresponding detection signal.

[0019] The hot water temperature sensor 18 detects the temperature of the hot water in the hot water storage tank 10 and outputs a corresponding detection signal to the control unit 31. A plurality of hot water temperature sensors 18 are provided at different height positions on the side of the hot water storage tank 10. When each of the plurality of hot water temperature sensors 18 detects a hot water temperature equal to or higher than a predetermined threshold value that is preset corresponding to the temperature of hot water in a sufficiently heated state, it outputs a corresponding detection signal to the control unit 31. The control unit 31 detects the amount of hot water in the hot water storage tank 10 that is in a sufficiently heated state (i.e., the amount of hot water stored) based on the number of hot water temperature sensors 18 that output detection signals.

[0020] The heat pump unit 19 operates using privately generated power and commercial power, and exchanges heat with hot water to boil the water. The heat pump unit 19 has a compressor 20, a water-refrigerant heat exchanger 21, an expansion valve 22, an air heat exchanger 23, a refrigerant pipe 26, and a blower 24.

[0021] The compressor 20 compresses the refrigerant to a high temperature and high pressure and transports it. The water-refrigerant heat exchanger 21 exchanges heat between the high temperature, high pressure refrigerant and the water from the hot water storage tank 10. The expansion valve 22 reduces the pressure and expands the refrigerant that has been heat exchanged in the water-refrigerant heat exchanger 21. The air heat exchanger 23 exchanges heat between outside air and the low pressure refrigerant to evaporate the low pressure refrigerant. The refrigerant pipe 26 circulates the refrigerant through the compressor 20, the water-refrigerant heat exchanger 21, the expansion valve 22, and the air heat exchanger 23. The blower 24 blows outside air to the air heat exchanger 23.

[0022] The heat pump unit 19 also has a discharge temperature sensor 25 and an outside air temperature sensor 30. The discharge temperature sensor 25 detects the temperature of the refrigerant discharged from the compressor 20, and outputs a corresponding detection signal to the control unit 31. The outside air temperature sensor 30 detects the outside air temperature, and outputs a corresponding detection signal to the control unit 31.

[0023] The circulation circuit 27 circulates the hot water in the hot water storage tank 10 between the hot water storage tank 10 and the water-refrigerant heat exchanger 21. The circulation circuit 27 has a heating supply pipe 27a, a heating return pipe 27b, a heating circulation pump 28, and a boiling temperature sensor 29.

[0024] The heating supply pipe 27a connects the lower part of the hot water storage tank 10 to the water-side inlet of the water-refrigerant heat exchanger 21. The heating return pipe 27b connects the water-side outlet of the water-refrigerant heat exchanger 21 to the upper part of the hot water storage tank 10. The heating circulation pump 28 is disposed on the heating supply pipe 27a and circulates hot water. The boiling temperature sensor 29 is disposed on the heating return pipe 27b and outputs a detection signal to the control unit 31.

[0025] Remote control 32 receives instructions from a user regarding water heating apparatus 1, such as the set temperature of hot water to be supplied to the hot water terminal.

[0026] Control unit 31 has a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc., and stores various programs and data necessary for the control of control unit 31. Control unit 31 controls the operation of water heating apparatus 1 as a whole in accordance with the various programs. Control unit 31 is connected to remote control 32 and communicates with remote control 32 bidirectionally.

[0027] The control unit 31 has a function for executing a daytime boiling determination process (described later). Here, Fig. 2 is a functional block diagram of the control unit 31 and the server 6. In Fig. 2, only the functions necessary for the daytime boiling determination process are shown, and other functions are omitted. The control unit 31 has a memory unit 50, a weather forecast information acquisition unit 41, an execution determination unit 42, and a mode acquisition unit 43.

[0028] The memory unit 50 stores information acquired from the user terminal 9 for the daytime boiling determination process, such as selection mode information 51, system capacity information 52, boiling time zone information 53, in-house power consumption information 54, and area information 55, which will be described later.

[0029] The weather forecast information acquisition unit 41 acquires weather forecast information 61 for a specific time period from the server 6. The weather forecast information 61 is weather defined by cloud cover, for example, three types: sunny (first weather), cloudy (second weather), and rain. Sunny is weather with the least cloud cover and the highest power generation efficiency of the solar power generation system 3. Cloudy is weather with more cloud cover than sunny and with a lower power generation efficiency of the solar power generation system 3 than sunny. Rain is weather in which the solar power generation system 3 does not generate power, or even if it does generate power, the power generation efficiency is lower than sunny and may be lower than cloudy.

[0030] The predetermined time period is a time period included in the daytime when the solar power generation system 3 is capable of generating power (hereinafter referred to as the "power generation time period"), for example, from 9:00 to 15:00. The weather forecast information acquisition unit 41 acquires weather forecast information 61 for each predetermined time period (for example, every hour) during the power generation time period from the server 6.

[0031] The execution determination unit 42 determines whether or not to perform boiling water using the self-generated power at any time during the power generation time zone, based on the predicted power generation amount of the self-generated power. The predicted power generation amount is calculated based on weather forecast information 61 acquired by the weather forecast information acquisition unit 41 (described later). Boiling water using self-generated power is an operation in which the heat pump unit 19 is operated using the self-generated power at any time during the power generation time zone to boil the hot water circulating through the circulation circuit 27. The execution determination unit 42 refers to the selected mode information 51 stored in the memory unit 50, and makes a determination based on the selected determination mode.

[0032] The mode acquisition unit 43 acquires information on the judgment mode selected by the user from the user terminal 9. The mode acquisition unit 43 stores the acquired judgment mode in the storage unit 50 as selected mode information 51. The judgment mode is a mode related to the judgment of the execution judgment unit 42, and is provided for the user to select. The judgment modes consist of a standard mode (first mode) and an aggressive mode (second mode).

[0033] The standard mode is a mode in which the execution determination unit 42 determines to perform daytime boiling using self-generated power only when there is a high degree of certainty that the self-generated power required for boiling can be obtained (for example, when the weather forecast information 61 is sunny). The proactive mode is a mode in which the execution determination unit 42 determines to perform daytime boiling even when there is a lower certainty that the self-generated power required for boiling can be obtained than is assumed in the standard mode (for example, when the weather forecast information 61 is cloudy).

[0034] That is, the proactive mode makes it easier for the execution determination unit 42 to determine that daytime heating using self-generated power is to be performed than the standard mode. For example, the standard mode is a mode in which it is determined that daytime heating using self-generated power is to be performed only when it is sunny, whereas the proactive mode is a mode in which it is determined that daytime heating using self-generated power is to be performed when it is sunny or cloudy. "Cloudy" has a range of cloud cover, and the same "cloudy" includes cases where the cloud cover allows the required amount of power to be obtained and cases where the cloud cover does not allow the required amount of power to be obtained. Therefore, even if it is determined that daytime heating using self-generated power is to be performed when the proactive mode is selected, the certainty of obtaining the amount of power generated is lower than in the standard mode. That is, on a cloudy day with a lot of cloud cover, there is a risk that sufficient self-generated power cannot be secured and daytime heating must be performed using commercial power during the day, when the unit price of electricity is relatively high.

[0035] Next, a daytime heating determination process executed by control unit 31 of water heating apparatus 1 in this embodiment will be described in detail. First, as a premise for the daytime heating determination process, a problem faced by water heating apparatus 1 will be described.

[0036] The water heater 1 boils hot water using commercial power or privately generated power. The unit price of commercial power is set lower at night (second time period) than during the day (first time period). For this reason, when using commercial power, it is preferable for the water heater 1 to boil hot water at night (night boiling operation) rather than during the day (day boiling operation) in order to reduce the burden on the user's electricity bill.

[0037] However, when a solar power generation system 3 is installed in a house together with the hot water heater 1, it is preferable to heat hot water using privately generated power rather than commercial power. The power generation efficiency of the solar power generation system 3 varies depending on the hours of sunlight and the amount of solar radiation. Therefore, in order for the hot water heater 1 to heat hot water using privately generated power, the solar power generation system 3 needs to know whether or not it can obtain the amount of power required to heat the amount of hot water required by the user during the daytime.

[0038] For example, when the HEMS centrally manages the energy used in the home, the hot water heater 1 can obtain the actual power generation amount of the solar power generation system 3 and the predicted value of the home's power consumption, and can determine whether or not to use the self-generated power to boil water depending on the power generation amount. However, in homes where a HEMS is not installed, this is currently difficult.

[0039] In other words, the water heating device 1 determines based on weather forecast information 61 that the amount of self-generated electricity required for boiling water will be available during the daytime the following day, and by reducing the amount of hot water to be boiled during the night, it is possible to reduce the amount of commercial electricity used and increase the amount of self-generated electricity used.

[0040] When the actual amount of power generated and the actual amount of power consumed by electrical load devices other than the hot water heater 1 can be grasped by the HEMS, these actual amounts of power generated and power consumed can be used to predict the amount of surplus power available for water heating with privately generated power during the day. However, in homes where a HEMS is not installed, the accuracy of predicting the amount of surplus power is relatively low because the actual amount of power generated cannot be used. For this reason, even if it is decided to heat water during the daytime of the following day, there is a risk that the amount of power cannot actually be obtained and water will be heated using commercial power during the day, when the unit price of electricity is high.

[0041] In order to ensure that surplus electricity from the solar power generation system 3 is available for use in heating the water heater 1, it is preferable to decide to perform daytime heating only when the weather forecast information 61 indicates sunny weather, which is highly efficient at generating electricity, and to perform nighttime heating to heat the entire required amount of hot water when it is cloudy or rainy, and not to perform daytime heating.

[0042] However, when the system capacity of the solar power generation system 3 is large, a certain amount of power can be expected even on cloudy days, so some users may wish to actively perform daytime heating. Therefore, the hot water supply device 1 in this embodiment executes a daytime heating determination process to perform daytime heating using privately generated power while reflecting the wishes of each user.

[0043] FIG. 3 is a flowchart illustrating the daytime boiling determination process executed by the control unit 31.

[0044] FIG. 4 is a conceptual diagram of the process executed in the water heating apparatus when it is determined in the daytime heating determination process that daytime heating is impossible.

[0045] FIG. 5 is a conceptual diagram of the process executed in the water heating apparatus when it is determined in the daytime heating determination process that daytime heating is possible.

[0046] This daytime heating determination process is executed repeatedly while hot water supply device 1 is activated, for example.

[0047] In step S1, the weather forecast information acquisition unit 41 determines whether the primary judgment time has arrived. The primary judgment time is a preset time at which weather forecast information 61 for the power generation time period of the next day is acquired from the server 6. The primary judgment time is, for example, the timing at which night heating can be completed after it is determined in step S4 described below that all of the hot water that needs to be heated can be heated in the night heating. From the viewpoint of the accuracy of the weather forecast, the primary judgment time is preferably a time as close as possible to the power generation time period (for example, 11pm).

[0048] When the weather forecast information acquisition unit 41 determines that the primary judgment time has not yet arrived (NO in step S1), it waits until the primary judgment time arrives. On the other hand, when the weather forecast information acquisition unit 41 determines that the primary judgment time has arrived (YES in step S1), it acquires weather forecast information 61 from the server 6 in step S2. Here, FIG. 6 is an explanatory diagram conceptually showing information required to execute the daytime boiling judgment process when the standard mode is selected. FIG. 7 is an explanatory diagram conceptually showing information required to execute the daytime boiling judgment process when the aggressive mode is selected. In FIG. 6, the weather forecast information 61 acquired at the primary judgment time and the weather forecast information 61 acquired at the secondary judgment time are shown. In FIG. 7, the weather forecast information 61 acquired at the primary judgment time is shown.

[0049] Weather forecast information acquisition unit 41 acquires weather forecast information 61 for the corresponding region from server 6 based on regional information 55 relating to the region of the house in which hot water heating apparatus 1 is installed. Here, Fig. 8 is a diagram showing an example of a display screen when information required for performing daytime boiling determination processing is received from a user at user terminal 9.

[0050] User terminal 9 sends instructions for operating water heating apparatus 1 and views the current usage status and past usage history of water heating apparatus 1, for example by downloading from a specified server and installing an application program (app) created and provided exclusively by water heating apparatus 1. Control unit 31 provides user terminal 9 with necessary information required for these processes, and executes instructions obtained from user terminal 9 in water heating apparatus 1. In this embodiment, control unit 31 accepts necessary information from user terminal 9 on display screen 9a in Fig. 8 as initial setting for executing the daytime boiling determination process.

[0051] The control unit 31 acquires the regional information 55 by accepting information on prefectures and cities, towns and villages from the user terminal 9 via the application. The storage unit 50 stores the acquired regional information 55.

[0052] Server 6 stores in advance weather forecast information 61 for multiple locations across the country, provided by, for example, a weather information provider. Alternatively, when weather forecast information 61 is requested by water heating apparatus 1, server 6 acquires weather forecast information 61 from a specified data server. Weather forecast information acquisition unit 41 requests and acquires corresponding weather forecast information 61 from server 6 based on area information 55. Weather forecast information acquisition unit 41 acquires hourly weather forecast information 61 for the power generation time period from 9:00 to 15:00, for example, as shown in Figs. 6 and 7.

[0053] In step S3, the execution determination unit 42 determines whether or not to perform daytime heating using privately generated power, which operates the heat pump unit 19 with privately generated power to heat water during the power generation time period. That is, the execution determination unit 42 determines whether or not daytime heating is possible by operating the heat pump unit 19 with privately generated power instead of commercial power, based on the predicted power generation amount of privately generated power.

[0054] Specifically, execution determination unit 42 calculates the predicted power generation amount based on the contents of the obtained weather forecast information 61, i.e., the power generation rates assigned to sunny, cloudy, and rainy days. Furthermore, execution determination unit 42 compares the surplus power amount obtained by subtracting the amount of power consumed by air conditioners, etc. 7 (hereinafter simply referred to as "in-house power consumption") from the predicted power generation amount with the amount of power consumed by heat pump unit 19 when boiling water. Execution determination unit 42 compares the surplus power amount with the amount consumed by heat pump unit 19 (hereinafter simply referred to as heat pump power consumption), and if the surplus power amount is greater than the amount of heat pump power consumption, determines to boil water using self-generated power.

[0055] As described above, the judgment mode is set by the user when the mode acquisition unit 43 accepts the selection via the user terminal 9. On the display screen 9a of the user terminal 9 in Fig. 8, the judgment mode is set by selecting the "aggressive" button or the "standard" button. The mode acquisition unit 43 stores information related to the judgment mode accepted by the user as selected mode information 51.

[0056] When the standard mode is selected, the execution determination unit 42 sets the power generation rate to 0.6 if the weather forecast information 61 is fine. Also, when it is cloudy or raining, the power generation rate is set to 0. When the aggressive mode is selected, the power generation rate is set to 0.6 if the weather forecast information 61 is fine. Also, when it is cloudy, the power generation rate is set to 0.4. Also, when it is raining, the power generation rate is set to 0.

[0057] When the aggressive mode is selected, the power generation rate is set to be higher in the cloudy state than when the standard mode is selected. That is, the execution determination unit 42 uses different methods for calculating the predicted power generation amount when the standard mode is selected and when the aggressive mode is selected. This makes it easier to determine that water boiling should be performed using self-generated power when the aggressive mode is selected by the user than when the standard mode is selected.

[0058] The predicted power generation amount is calculated by multiplying the system capacity of the solar power generation system 3 by the power generation rate allocated to the obtained weather forecast information 61. The system capacity is the amount of power generated per unit time (per hour) of the solar power generation system 3, and is a value that indicates the power generation capability, and is a value unique to the solar power generation system 3. The control unit 31 receives the system capacity from the user terminal 9 on the display screen 9a of the application as shown in FIG. 8, and stores it in the storage unit 50 as system capacity information 52.

[0059] When the standard mode is selected and weather forecast information 61 as shown in FIG. 6 is obtained, the execution determination unit 42 calculates the predicted power generation amount for each hour by multiplying the system capacity and the power generation rate.

[0060] The home power consumption is, for example, an average home power consumption per unit time (per hour) and is a value set by the user. The control unit 31 stores the home power consumption received from the user terminal 9 via the display screen 9a in the storage unit 50 as home power consumption information 54.

[0061] The execution determination unit 42 calculates the amount of surplus power by subtracting the amount of in-house power consumption from the predicted amount of power generation. That is, the amount of surplus power is defined as the system capacity×power generation rate−the amount of in-house power consumption.

[0062] The heat pump power consumption is a value obtained by multiplying the amount of power consumed by the heat pump unit 19 during boiling water, which is preset and stored in the control unit 31, by a slight additional coefficient. The heat pump power consumption is a value that can vary depending on the season, day of the week, etc. For example, the heat pump power consumption is normally set to a value of 1 kW multiplied by a coefficient of 1.2. Also, in winter, when the heat pump unit 19 is used more frequently, it is set to a value of 1.5 kW multiplied by a coefficient of 1.2.

[0063] In step S4, the execution determination unit 42 determines whether or not the calculated amount of surplus power is greater than the amount of power consumed by the heat pump, thereby determining whether or not daytime boiling of hot water is possible with the amount of surplus power from the self-generated power. The execution determination unit 42 determines that daytime boiling is possible when the amount of surplus power is greater than the amount of power consumed by the heat pump for a continuous period of time required for boiling (e.g., three hours). For example, in the examples of Figs. 6 and 7, the amount of surplus power is greater than the amount of power consumed by the heat pump for three consecutive hours in both determination modes, and the operation determination is ◯, so the execution determination unit 42 determines that daytime boiling is possible.

[0064] If the execution determination unit 42 determines that daytime boiling is not possible (NO in step S4), then in step S5, nighttime boiling is performed to boil all of the hot water that needs to be boiled (see FIG. 4). That is, since the required hours of sunlight and amount of solar radiation are not available during the daytime of the following day and daytime boiling cannot be performed, the entire amount of hot water is boiled using commercial electricity during the night when the electricity rate is low. The control unit 31 then returns to step S1 and repeats the subsequent processes.

[0065] On the other hand, when the execution determination unit 42 determines that daytime boiling is possible (YES in step S4), in step S6, it determines the start time of daytime boiling. The execution determination unit 42 determines the earliest time period among the times obtained continuously for the time required for boiling as the start time of daytime boiling. This is because it can be said that the weather forecast information 61 for a time close to the timing when the weather forecast information 61 was acquired has a high degree of accuracy. For example, in the examples of Figures 5 to 7, 9:00, the earliest time among the times when daytime boiling can be performed for three consecutive hours, is determined as the start time.

[0066] Furthermore, the execution determination unit 42 may receive from the user a setting for a time period during which daytime boiling will be performed. On the display screen 9a of the user terminal 9 in FIG. 8, the time period setting is received by selecting the "early" button, the "standard" button, or the "late" button. The control unit 31 stores the information on the boiling time period received from the user terminal 9 in the storage unit 50 as boiling time period information 53. The peak power generation of the solar power generation system 3 differs for each user depending on the installation angle of the solar power generation panel 4, etc. For this reason, the water heating device 1 allows the user to select a time period during which daytime boiling will be performed using self-generated power, thereby performing boiling that is tailored to each user.

[0067] In step S7, the control unit 31 performs nighttime boiling using commercial power for a portion of the amount of hot water that needs to be boiled (see FIG. 5). That is, since it is predicted that the required hours of sunshine and amount of solar radiation will be obtained during the daytime of the next day, a portion of the hot water that needs to be boiled (e.g., 20 to 60% of the total amount) is boiled using commercial power during the night when the unit price of electricity is low.

[0068] In step S8, the weather forecast information acquisition unit 41 determines whether or not the secondary determination time has arrived. The secondary determination time is a preset time at which weather forecast information 61 for the power generation time period on the day when the daytime boiling is performed is acquired from the server 6. The secondary determination time is a time before the start time of the daytime boiling that is performed in step S13 described later.

[0069] If the weather forecast information acquisition unit 41 determines that the secondary judgment time has not yet arrived (NO in step S8), it waits until the secondary judgment time arrives. On the other hand, if the weather forecast information acquisition unit 41 determines that the secondary judgment time has arrived (YES in step S8), in step S9, it acquires the weather forecast information 61 from the server 6 in the same way as in step S2.

[0070] The weather forecast information acquisition unit 41 acquires hourly weather forecast information 61 for a power generation time period from 9:00 to 15:00, as shown in FIG.

[0071] In step S10, the execution determination unit 42 determines whether or not there has been a change in the weather forecast information 61 acquired at the secondary determination time relative to the weather forecast information 61 acquired at the primary determination time. If the execution determination unit 42 determines that there has been a change (YES in step S10), in step S11, the execution determination unit 42 determines the start time of daytime boiling based on the changed weather forecast information 61. The execution determination unit 42 determines the earliest time period among the times at which the time required for boiling is continuously obtained as the start time of daytime boiling. The execution determination unit 42 may also determine the start time so that daytime boiling is performed in the time period with the largest total amount of surplus power over three consecutive hours.

[0072] For example, in the example of Fig. 6, the weather forecast information 61 at 10:00 changed from sunny to cloudy, so the surplus power amount was smaller than the heat pump power consumption amount, and the operation judgment was changed to x. Therefore, the execution judgment unit 42 judges that daytime heating starting from 9:00 is impossible. The execution judgment unit 42 determines that 11:00, a time when daytime heating can be performed for three consecutive hours, is the start time.

[0073] If it is determined that there is no change in the weather forecast information 61 (NO in step S10) and after step S11, in step S12, the control unit 31 determines whether or not the start time determined in the start time determination step S6 or S11 has arrived. If the control unit 31 determines that the start time has not yet arrived (NO in step S12), it waits until the start time arrives. On the other hand, if the control unit 31 determines that the start time has arrived (YES in step S12), in step S13, it boils the remaining amount of hot water that needs to be boiled using privately generated electricity (see FIG. 5). Thereafter, the control unit 31 returns to step S1 and repeats the subsequent processes.

[0074] In the daytime heating determination process described above, if a home has a HEMS installed, it is possible to obtain information necessary for determining whether or not daytime heating should be performed, such as system capacity, from information obtained from each device connected to the HEMS. On the other hand, if a HEMS is not connected to the water heating apparatus 1 as in this embodiment, it is difficult to grasp such information. Therefore, even if a HEMS is not connected, the water heating apparatus 1 in this embodiment can easily realize the cooperation between the photovoltaic power generation system 3 and the water heating apparatus 1 in the same way as a HEMS by obtaining the necessary information obtained from the user and weather forecast information 61.

[0075] Therefore, water heating apparatus 1 can use the power self-generated by solar power generation system 3 for boiling water while reflecting the desires of each user. In particular, water heating apparatus 1 determines whether or not to perform daytime boiling operation using a determination mode selected by the user from two types of determination modes. This allows water heating apparatus 1 to calculate the predicted power generation amount, which is calculated based on weather forecast information 61, based on the desires of the user.

[0076] Specifically, when a user actively wants to use self-generated power to heat water during the day, the water heating apparatus 1 makes it easier to use self-generated power to heat water. On the other hand, when a user does not want to take the risk of using commercial power during the day when the electricity rate is relatively high due to a discrepancy between the weather forecast information 61 and the actual weather conditions, the water heating apparatus 1 makes it easier to heat water using self-generated power only when it is predicted that there is sufficient surplus power. This allows the water heating apparatus 1 to use self-generated power to heat water according to the user's wishes, even in a home that does not have a HEMS installed, improving usability for the user.

[0077] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims.

[0078] For example, the power generation rate value used in the daytime boiling determination process is just an example, and may be set to any value.

[0079] Furthermore, the server 6 acquires information necessary for the daytime boiling judgment process from the user and stores it, but the control unit 31 may acquire the information directly from the user. [Explanation of symbols]

[0080] 1. Storage tank type hot water supply system (hot water supply system) 3. Solar power generation system 6 Server 7 Air conditioners, etc. 8 Network 9 User terminals 10 Hot water tank 19 Heat pump unit 27 Circulation circuit 31 Control Unit 32 Remote Control 41 Weather forecast information acquisition unit 42 Execution decision unit 43 Mode acquisition section 50 Storage section 51 Selection mode information 52 System Capacity Information 53 Boiling time information 54 Home power consumption information 55 Local Information 61 Weather forecast information 100 Hot Water System

Claims

1. A hot water storage tank for storing hot water; a heat pump unit that operates using privately generated power generated by a solar power generation system and commercial power supplied from a commercial power source to heat the hot water; A weather forecast information acquisition unit that acquires weather forecast information for a predetermined time period; an execution determination unit that determines whether or not to perform boiling of the hot water using the self-generated power by operating the heat pump unit with the self-generated power during the specified time period based on a predicted power generation amount of the self-generated power calculated based on the weather forecast information; and a mode acquisition unit that acquires information about a mode selected by a user from a first mode and a second mode, which are modes related to the determination of the execution determination unit; The execution determination unit is In order to make it easier to determine that boiling water using the self-generated electric power is to be performed when the second mode is selected than when the first mode is selected, a calculation method of the predicted electric power generation amount is made different between when the first mode is selected and when the second mode is selected; A storage type hot water supply device in which the start time for boiling water using the self-generated power is set to the earliest time period among the specified time periods in which it is determined that boiling water using the self-generated power will be performed, the time period that is obtained consecutively for the time required for boiling water using the self-generated power relative to the timing at which the weather forecast information was obtained.

2. the weather forecast information includes a first weather and a second weather having more cloudiness than the first weather, the execution determination unit calculates the predicted power generation amount based on a power generation rate assigned to each of the first weather and the second weather, A hot water storage type hot water supply device as described in claim 1, wherein the power generation rate is set so that the power generation rate in the second weather is higher when the second mode is selected than when the first mode is selected.

3. The hot water storage type hot water supply device according to claim 2 , wherein the execution determination unit calculates the predicted power generation amount based on a capacity of the photovoltaic power generation system, which is a value set by the user.

4. the weather forecast information includes a first weather and a second weather having more cloudiness than the first weather, The storage type hot water supply device of claim 1, wherein the execution determination unit determines that when the weather forecast information is the second weather, the solar power generation system will not generate power when the first mode is selected, and that the solar power generation system will generate power when the second mode is selected.

5. 5. The storage type hot water supply device according to claim 2, wherein the first weather is sunny and the second weather is cloudy.

6. A storage type hot water heater according to any one of claims 1 to 5, wherein the execution determination unit determines to perform boiling using the self-generated electricity when the surplus electricity amount obtained by subtracting the amount of electricity consumed by electrical load equipment other than the heat pump unit from the predicted power generation amount is greater than the amount of electricity consumed by the heat pump unit when boiling the hot water.

7. The hot water storage type hot water supply device according to claim 6 , wherein the amount of power consumed by the electrical load devices other than the heat pump unit is a value set by the user.

8. The commercial power is set at a lower unit price in the second time period than in the first time period, The storage type hot water supply device according to claim 1 , wherein the predetermined time period is a time period included in the first time period.

Images