Power control device and power control method

Abstract

To promote self-consumption of power by consumers by carrying out possible idle heating without impairing the benefits of shift heating.SOLUTION: A power control device including a storage-type water heater and a solar power generation device includes a surplus power prediction unit that calculates predicted surplus power for each hour, a water heating power acquisition unit that acquires water heating power for each hour of the storage-type water heater, a shift water heating setting unit that compares the predicted surplus power with the water heating power to schedule daytime shift water heating operation, a shift water heating control unit that, when performing daytime shift water heating operation, reduces the amount of water to be heated by prior nighttime water heating operation, and a spare-moments water heating control unit that compares the surplus power for each hour with the water heating power for each hour to determine whether there is time available for spare-moments water heating operation which performs water heating operation using surplus power during a period when daytime shift water heating operation is not being performed, and performs spare-moments water heating operation if possible.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a power control device and a power control method for controlling a power system of a consumer that includes a storage type hot water heater and a solar power generator. [Background technology]

[0002] The following is known regarding a customer's storage-type hot water supply system equipped with a hot water storage tank for storing hot water generated by a heating means and a solar power generation facility: In order to self-consumer surplus electricity that exceeds the electricity consumed by the customer during the day when electricity generated by the solar power generation facility is available, the surplus electricity for the day is predicted, and if the surplus electricity is high, the amount of water to be heated during the nighttime heating operation of the storage-type hot water supply system on the previous day is reduced compared to when the surplus electricity is low (see, for example, Patent Document 1). Also known is a storage-type hot water supply system that includes a solar power generation system, a heat pump heating means for heating water in a hot water storage tank, a heat pump power consumption storage means for storing the power consumption of the heat pump heating means, a surplus power monitoring means, and a water heating control means. This storage-type hot water supply system reduces the amount of water heated during the previous nighttime period by the amount that can be heated with the surplus power generated, assuming that the water will be heated using surplus power generated during the daytime. The surplus power monitoring means monitors the surplus power generated by the solar power generation system on that day and heats the water in the hot water storage tank if the generated power is greater than the heat pump power consumption. The water heating control means stops the water heating operation if the generated power is equal to or less than the heat pump power consumption. In this way, water is heated when there is surplus power on that day (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-148287 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-044849 Summary of the Invention [Problem to be solved by the invention]

[0004] In the case of a method such as that described in Patent Document 1, in which surplus power is predicted for the day and, if there is surplus power, nighttime water heating operation from the previous day is suppressed and water heating is performed using the surplus power for that day (hereinafter referred to as daytime shift water heating operation), daytime shift water heating operation can only be scheduled when a certain amount of surplus power is expected for that day. This is because heating water to store hot water in the hot water storage tank requires continuous heating for a certain period of time, which requires a corresponding amount of surplus power. Even if daytime shift water heating operation is scheduled, if the weather on the day is cloudy instead of the predicted sunny weather, and the suppression of nighttime water heating operation results in a shortage of hot water storage for that day, water heating must be performed using power from the power grid on that day. In this case, water heating will be performed using more expensive power than nighttime water heating. Therefore, shift water heating can only be scheduled during periods of relatively stable weather. On the other hand, as in Patent Document 2, a method of monitoring surplus electricity for the day and heating water if there is surplus electricity available for heating, even for a short period of time (hereinafter referred to as "gap heating"), is an effective method in that it allows for flexible self-consumption using a storage-type hot water heater. However, shift heating is sometimes used as a means of increasing demand response (DR), in which case it is required to perform daytime shift heating operation at a specified time on the day to heat a specified amount of hot water. Simply combining such shift heating and gap heating may result in the inability to perform daytime shift heating operation for the planned amount of hot water, resulting in the imposition of penalties related to demand response. On the other hand, in recent years, growing concern about environmental issues and rising energy resource prices have led to an increasing demand for self-consumption of electricity among consumers. This invention has been made in consideration of the above circumstances, and provides a power control device and a power control method that can promote self-consumption of electricity by consumers by performing gap heating where possible without compromising the benefits of shift heating. [Means for solving the problem]

[0005] The present invention provides a power control device that controls the power system of a consumer connected to a power grid and including a storage-type hot water heater and a solar power generation device, and that includes: a surplus power prediction unit that determines in advance the predicted hourly surplus power of the power generated by the solar power generation device; a heat-up power acquisition unit that acquires the hourly heat-up power used to heat the water from the storage-type hot water heater; a shift heat-up setting unit that compares the predicted surplus power with the magnitude of the heat-up power to determine a schedule for daytime shift heat-up operation, including the case where operation is not performed; a shift heat-up control unit that, when the daytime shift heat-up operation is to be performed, performs the daytime shift heat-up operation by suppressing the amount of heat generated by the prior nighttime heat-up operation; and a gap heat-up control unit that compares the magnitude of the hourly surplus power with the magnitude of the hourly heat-up power to determine whether there is time available for gap heat-up operation, which uses the surplus power to heat water during periods when the daytime shift heat-up operation is not being performed, and performs the gap heat-up operation if there is time available.

[0006] From a different perspective, the present invention provides a power control method comprising the steps of: a control unit of a power control device that controls a power system of a consumer connected to a power grid, the control unit of which includes a hot water storage type water heater and a solar power generation device, determining in advance the predicted hourly surplus power of the power generated by the solar power generation device; obtaining the hourly heating power to be used for heating the hot water storage type water heater; comparing the magnitude of the predicted surplus power with the heating power to determine a schedule for daytime shift heating operation, including the case where operation is not performed; if the daytime shift heating operation is performed, reducing the amount of heating by prior nighttime heating operation; and comparing the magnitude of the hourly surplus power with the hourly heating power to determine whether there is time available for gap heating operation, which uses the surplus power to heat water during periods when the daytime shift heating operation is not performed, and performing the gap heating operation if there is time available. [Effects of the Invention]

[0007] The power control device of this invention is equipped with a shift heating control unit that, when performing daytime shift heating operation, performs daytime shift heating operation by suppressing the amount of heating generated in the previous nighttime heating operation, and a gap heating control unit that compares the amount of surplus power per hour with the amount of heating power per hour to determine whether there is time available for gap heating operation, which uses the surplus power to heat water during periods when daytime shift heating operation is not being performed, and performs gap heating operation if there is time available.Therefore, it is possible to perform gap heating where possible without compromising the benefits of daytime shift heating, thereby promoting self-consumption of electricity by consumers. The power control method according to the present invention also provides the same effects. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a block diagram showing a configuration example of a power system according to an embodiment; [Figure 2] 10 is an explanatory diagram showing an example of a time when daytime shift heating operation is possible and a time when gap heating operation is possible according to an embodiment of the present invention. FIG. [Figure 3] 4 is a first flowchart illustrating an example of processing executed by a power control unit in the first embodiment. [Figure 4] 10 is a second flowchart illustrating an example of processing executed by the power control unit in the first embodiment. [Figure 5] 10 is a third flowchart illustrating an example of processing executed by a power control unit in the first embodiment. [Figure 6] 10 is a fourth flowchart illustrating an example of processing executed by a power control unit in the first embodiment. [Figure 7] 4 is a flowchart showing an example of processing executed by a power control unit in the second embodiment, instead of the processing shown in FIG. 3; [Figure 8] 6 is a first flowchart showing an example of processing executed by a power control unit in the second embodiment, in place of that in FIG. 5; [Figure 9]6 is a second flowchart showing an example of processing executed by the power control unit in the second embodiment, in place of that in FIG. 5; [Figure 10] 7 is a flowchart showing an example of processing executed by a power control unit in the second embodiment, instead of the processing shown in FIG. 6; [Figure 11] 10 is a flowchart showing an example of processing executed by a power control unit in the third embodiment, instead of the processing shown in FIG. 3; [Figure 12] 6 is a flowchart showing an example of processing executed by a power control unit in the third embodiment, instead of FIG. 5; [Figure 13] 7 is a flowchart showing an example of processing executed by a power control unit in the third embodiment, instead of the processing shown in FIG. 6; DETAILED DESCRIPTION OF THE INVENTION

[0009] The present invention will be described in more detail below with reference to the accompanying drawings. Note that the following description is given by way of example only in all respects and should not be construed as limiting the present invention. <Example of power system configuration> First, a configuration example of a power system according to this embodiment will be described. FIG. 1 is a block diagram showing an example of the configuration of a power system according to this embodiment. As shown in FIG. 1, power system 10 according to this embodiment includes photovoltaic power generation device 11, hot water storage device 12, electrical appliances 13-1 to 13-n, power conditioner 14 (also referred to as PCS, an acronym for Power Conditioning System), and HEMS 15, and is connected to an external power grid 100. HEMS (Home Energy Management System) 15 is a device that manages the power of power system 10. HEMS 15 manages the power generated by photovoltaic power generation device 11, the power used by hot water storage device 12 and electrical appliances 13-1 to 13-n, the charging and discharging of storage battery 102, and the purchase and sale of power with respect to power grid 100. HEMS 15 can communicate with an external HEMS server 17 via a network. HEMS server 17 obtains weather information from the Japan Meteorological Agency and service providers and provides the information to HEMS 15.

[0010] In FIG. 1, the power generated by the solar power generation device 11 is P PV , the power consumed by the electrical devices 13-1 to 13-n is P L1 ~P Ln In addition, the power consumed by the hot water storage type hot water supply device 12 is P L0 Furthermore, the input and output power of the power conditioner is P PCS , the power transmitted and received from the power grid is P s Solar power generation device 11 includes a solar cell module, and supplies DC power generated by the solar cell module to power conditioner 14. Power conditioner 14 converts the DC power supplied from solar power generation device 11 to a predetermined voltage using DC / DC converter 14D, and outputs the converted voltage to electrical devices 13-1 to 13-n and power system 100 via inverter 14V.

[0011] As shown by the dotted line in FIG. 1 , the power system 10 may include an optional storage battery 102. In this case, the inverter 14V of the power conditioner 14 is a bidirectional inverter. The storage battery 102 is connected to the DC side of the inverter 14V, i.e., the side of the DC / DC converter 14D, via the bidirectional DC / DC converter 14B. When the storage battery 102 is being charged, the bidirectional DC / DC converter 14B converts the voltage from the solar power generation device 11 or the power system 100 into a DC voltage of an appropriate magnitude for charging and provides it to the storage battery. When the storage battery 102 is being discharged, the DC power from the storage battery 102 is supplied to the hot water storage type water heater 12, the electrical appliances 13-1 to 13-n, and the power system 100 via the bidirectional DC / DC converter 14B and the inverter 14V. The HEMS 15 and the power conditioner 14 may be integrated into one unit.

[0012] The HEMS 15 is configured to include hardware resources centered around a CPU, memory, input / output circuits, a communication interface circuit, and a timer circuit. In this embodiment, the HEMS 15 may also include a power control unit 16. The power control unit 16 includes a surplus power prediction unit 16-1, a water heating power acquisition unit 16-2, a shift water heating setting unit 16-3, a shift water heating control unit 16-4, and a gap water heating control unit 16-5. The power control unit 16 controls the power conditioner 14 to control the power of the power system 10. That is, the power control unit 16 supplies the power generated by the solar power generation device 11 to the electrical appliances 13-1 to 13-n and the power grid 100. If the power system 10 includes a storage battery 102, the power control unit 16 further controls the direction of charging and discharging the battery and the power (amount of power) thereof. The power control unit 16 also communicates with the hot water storage device 12. The details of communication with storage type hot water heater 12 will be described later, but it is preferable to communicate with storage type hot water heater 12 based on standardized communication specifications such as ECONET Lite.

[0013] In addition to a configuration in which the HEMS 15 includes the power control unit 16, a configuration in which the HEMS server 17 also includes the power control unit 16 may also be used. Alternatively, the power control unit 16 may be distributed between the HEMS 15 and the HEMS server 17. In this case, the elements of the power control unit 16 arranged in the HEMS server 17 and the elements of the power control unit 16 arranged in the HEMS 15 jointly control the power system 10. Various modes of sharing of processing between the HEMS 15 and the HEMS server 17, which are physically located in different places, are conceivable. To encompass all of these, a power control device 18 including the HEMS 15 and the HEMS server 17 is shown in a dashed line frame in FIG. 1.

[0014] The power control unit 16 outputs the generated power P of the solar power generation device 11 from the power conditioner 14 at predetermined time intervals (for example, every 30 minutes). PV When the storage battery 102 is connected, its load power (positive is the power when charging, negative is the power when discharging) P PB Also, the power consumption P of each of the electric devices 13-1 to 13-n for each predetermined period is sequentially acquired. L1 ~PLn The total of the generated power P PV and the power consumption of each electrical device (P L1 ~P Ln ) is stored in memory as a history. The history is time-series data of the generated power and consumed power for each predetermined period. Furthermore, although not shown in FIG. 1, a smart meter or a CT sensor is used to measure the transmitted and received power P s Also, the electric power P used for heating is acquired from the hot water storage type hot water supply device 12. L0 The power control unit 16 obtains the actual value (actual power) for each hour of the power generation time P PV The power consumption P of the hot water storage type hot water supply device 12 and the electrical equipment 13-1 to 13-n L1 ~P Ln and the load power P of the storage battery 102 PB Furthermore, the current surplus power can be calculated based on the power information that is successively acquired. When the surplus power is a positive value, the power P transmitted and received from the power grid 100 is calculated. s is negative (electricity sold).

[0015] The HEMS 15 notifies the user of the status of the power system 10 via communication to the user's information terminal 19. The HEMS 15 also accepts user settings related to control of the power system 10 at the information terminal 19. For example, the HEMS 15 may accept an operation related to setting a schedule for the hot water storage type hot water heater 12 to heat water. The HEMS 15 may also accept an operation to switch from an automatic heating mode, in which heating is performed based on a preset schedule or a schedule based on past performance, to a manual heating mode, in which heating is performed in response to a user's instruction. An example of the information terminal 19 is a mobile terminal such as a smartphone or tablet terminal owned by the user, or a stationary or portable personal computer. Another example is a monitor (whether dedicated or not) installed in the home.

[0016] <Communication with storage-type hot water heater> The hot water storage device 12 uses electricity to heat water and stores it in a tank. The hot water storage device 12 heats and stores the predicted amount of hot water used in the tank during nighttime hours (late-night power hours) when the unit price of the power grid 100 is low, before the unit price of the power grid 100 becomes high. The hot water storage device 12 has a function to reduce the amount of power used for heating from the power grid 100 by suppressing nighttime heating operation, which heats water using power from the power grid 100 during nighttime hours, and performing daytime shift heating operation, which heats water using surplus power generated by the solar power generation system 11. The predicted amount of hot water used, or in other words, the target amount of hot water stored, is predicted based on, for example, learning the amount of hot water used each day in the past. Because the amount of hot water used varies depending on the season or time of year, the target amount of hot water stored each day is predicted by learning the amount of hot water used (history) for the past two weeks, for example.

[0017] Because it takes a certain amount of time to heat water, it is necessary to start heating it early to prevent hot water shortages. For example, if the amount of hot water stored to be heated during the nighttime hours is determined based on the average amount of hot water used each day in the past, the amount of hot water not wasted will not be large because the amount of hot water stored is not large enough to allow for a margin, but shortages will occur on days when usage is high. To prevent hot water shortages, it is necessary to predict hot water shortages early and increase the amount of hot water. As described above, determining the timing and amount of hot water to be heated by hot water storage device 12 is complex, and hot water storage device 12 autonomously controls these operations during automatic heating mode. HEMS 15 acquires status and information from hot water storage device 12 via communication. HEMS 15 then remotely controls hot water storage device 12 to perform daytime shift heating operation and gap heating operation so as not to conflict with the autonomous operation of hot water storage device 12 (operation in automatic heating mode) and operation based on user instructions (operation in manual heating mode).

[0018] Although not shown in FIG. 1 , HEMS 15 or HEMS server 17 may communicate with an aggregator that requests DR and perform control corresponding to the DR. Storage-type hot water heater 12 may then heat up in response to a request for upward DR, which increases power demand. Upward DR ensures power demand commensurate with the amount of solar power generated during the solar radiation hours on the day of the DR. The aggregator sends an upward DR request the day before. Upon receiving a request for upward DR for the next day, power control unit 16 heats up the amount of hot water in storage-type hot water heater 12 predicted to be needed the next morning during the nighttime hours. Then, power control unit 16 predicts the amount of hot water that may be heated during the daytime hours of the next day and the heating power corresponding to each hour. Then, it determines whether to shift the heating during the nighttime hours to the daytime hours of the next day, and if so, the start time of the heating. If daytime shift heating operation is scheduled for the next day, the heating time and heating amount for the scheduled daytime shift heating operation are updated. If no daytime shift boiling operation is scheduled for the following day, a new daytime shift boiling operation will be scheduled for the following day.

[0019] <Daytime shift heating operation and gap heating operation> Examples of daytime shift water heating operation and gap water heating operation will now be described. FIG. 2 is an explanatory diagram showing examples of times when daytime shift water heating operation is possible and times when gap water heating operation is possible. The left side of FIG. 2 shows an example of how the power control unit 16 determines the time period when daytime shift water heating operation is possible (daytime shift water heating possible period). The right side of FIG. 2 shows an example of how the power control unit 16 determines the time when gap water heating operation is possible. As of the day before daytime shift water heating operation, the power control unit 16 estimates the water heating power 21 required to perform daytime shift water heating operation on the day of daytime shift water heating operation, i.e., the day after the previous day. This estimation is performed based on the power information history and meteorological information related to the weather for that day obtained from the HEMS server 17. In the following explanation, the day after the previous day will be referred to as the current day.

[0020] In the example shown in FIG. 2, the water heating power 21 required for daytime shift water heating operation is continuous over three unit times (time increments). The value of the water heating power required for daytime shift water heating operation is acquired by the power control unit 16, acting as the water heating power acquisition unit 16-2, by querying the hot water storage-type hot water heater 12 via the HEMS. The hot water storage-type hot water heater 12 requires a certain amount of power to heat a predetermined amount of hot water all at once during daytime shift water heating operation. As a result, as shown in the example of FIG. 2, the hot water storage-type hot water heater 12 tends to require power over a long period of time. Note that the horizontal direction in FIG. 2 indicates a predetermined unit time (time increment). In the example shown in the lower part of FIG. 2, the unit time is one hour, and the eight unit times from 10:00 AM to 5:00 PM on the same day are the possible daytime shift water heating periods, i.e., the candidate time periods for daytime shift water heating operation. The possible daytime shift water heating periods are not limited to the time period from 10:00 AM to 5:00 PM, but can be any time period during which the solar power generation system 11 is capable of generating power. 2 shows an example of predicted surplus power for each unit time during the daytime shift available for heating. This is an example of predicted surplus power predicted by the power control unit 16 as the surplus power prediction unit 16-1. Note that the unit time is not limited to one hour, and may be, for example, 30 minutes or 90 minutes, as long as an appropriate value is applied depending on the characteristics of the power system 10.

[0021] The power control unit 16, functioning as the shift boil-up power setting unit 16-3, finds a time period among the candidate time periods for the predicted surplus power 22 during which boil-up power 21 required for daytime shift boil-up operation can be provided. Preferably, the power control unit 16 sequentially determines whether boil-up power 21 required for daytime shift boil-up operation can be provided, starting with the earliest of the candidate time periods. As shown in the example in the lower left of FIG. 2, the power control unit 16 first determines whether boil-up power 21 can be provided in the time period from 10:00 to 12:00 of the predicted surplus power 22. Because there is insufficient surplus power available for the unit time of 11:00, the determination result is No. This is indicated by an X in the example in FIG. 2. Next, the power control unit 16 determines whether boil-up power 21 can be provided in the time period from 11:00 to 13:00, one unit time later. Because there is also insufficient surplus power available for the unit time of 11:00, the determination result is No, and this determination result is indicated by an X in FIG. 2. Next, the power control unit 16 determines whether boil-up power 21 can be provided in the time period from 12:00 to 14:00, one unit time later. Since there is surplus power that can be provided by water heating power 21 during that time period, the result of the determination is Yes. The result of the determination is indicated by a circle in Figure 2. Based on the result of the determination, power control unit 16, functioning as shift water heating setting unit 16-3, schedules daytime shift water heating operation for the time period from 12:00 to 14:00 on that day, and requests hot water storage type water heater 12 to perform daytime shift water heating operation for the unit time starting from 12:00 on that day. The above is an example of determining whether daytime shift water heating operation is possible, and determining the schedule if possible.

[0022] Next, we will explain an example of gap boiling operation. Gap boiling operation is a method of boiling water when there is surplus power available for boiling water, even if there is no surplus power available for continuous boiling water over a long period of time, as in daytime shift boiling operation. The time available for gap boiling operation is shorter than the time available for daytime shift boiling operation. However, since energy efficiency is poor if the boiling time is extremely short, a minimum time is set and used for judgment. The unit time is determined based on this minimum time.

[0023] An example of gap boiling operation is shown on the right side of Figure 2. The power control unit 16, acting as the gap boiling control unit 16-5, finds a time period during which the boiling power 23 required for the gap boiling operation can be provided for each unit of time within the candidate time period on that day. Starting with the earliest time period among the candidate time periods, it sequentially determines whether the boiling power 23 required for the gap boiling operation can be provided. As shown in the example in the lower right of Figure 2, it determines whether the boiling power 23 required for the gap boiling operation can be provided from the surplus power 24 for that day for each unit of time within the candidate time period. In the example shown in Figure 2, the boiling power 23 can be provided for each unit of time from 1:00 PM and 3:00 PM. Because the time during which gap boiling operation can be performed is shorter than the time during which daytime shift boiling operation can be performed, it is easy to find a time period during which the boiling power 23 required for the gap boiling operation can be provided. Note that time periods during which daytime shift boiling operation is being performed on that day are given priority. Gap water heating operation is performed in the gaps between daytime shift water heating operation. Because daytime shift water heating operation is prioritized, the benefits of shift water heating are not lost. By performing gap water heating operation in addition to daytime shift water heating operation, it is possible to promote the consumer's own consumption of electricity. Even if daytime shift water heating operation is not possible, gap water heating operation can be performed to promote the consumer's own consumption of electricity. Furthermore, even if the tank of the hot water storage type hot water heater 12 is filled with hot water up to the amount predicted for use by nighttime water heating operation or daytime shift water heating operation at the start of gap water heating operation, gap water heating operation may be performed again. Even if the amount of hot water in the tank exceeds the amount predicted for use, this does not pose a problem and does not change the fact that surplus electricity is being consumed in-house. Furthermore, by performing gap water heating after daytime shift water heating operation, the amount of water to be heated in nighttime water heating operation on the same day can be reduced, which is expected to increase the consumer's own consumption rate of surplus electricity.

[0024] <Processing related to daytime shift heating operation and gap heating operation> Next, an example of the processing executed by the power control unit 16 for daytime shift water heating operation and gap water heating operation will be described with reference to a flowchart. Figures 3 to 6 are flowcharts showing an example of the flow of processing executed by the power control unit 16 in this embodiment. Figures 3 and 4 show processing executed on the day before daytime shift water heating operation and gap water heating operation, and Figures 5 and 6 show processing executed on the day of daytime shift water heating operation and gap water heating operation.

[0025] As shown in FIG. 3, the power control unit 16, functioning as the surplus power prediction unit 16-1, performs the following processing every day. First, on the day before the target day (the current day) for daytime shift water heating operation and gap water heating operation, the predicted power generation per unit hour by the solar power generation device 11 on that day is calculated (step S11). The predicted power consumption per unit hour to be consumed by the hot water storage type hot water supply device 12 and the electrical appliances 13-1 to 13-n on that day is also calculated. Furthermore, if the power system 10 includes a storage battery 102, the predicted power consumption per unit hour consumed by charging the storage battery 102 is calculated (step S12). Note that if the storage battery 102 is discharged, the predicted power consumption is calculated as a negative value. While FIGS. 3 and 4 illustrate the processing performed on the day before the daytime shift water heating operation and gap water heating operation, it does not necessarily have to be the day before midnight, and may be any time before the candidate time slot for the daytime shift water heating operation and gap water heating operation. It may also be more than 24 hours before that time slot. Using the power information, surplus power predictor 16-1 calculates the predicted surplus power for each unit time of the day in power system 10 (step S13). The predicted surplus power is calculated by subtracting the predicted power consumption from the predicted power generation.

[0026] Furthermore, the power control unit 16, functioning as the water heating power acquisition unit 16-2, estimates the power (water heating power) required for water heating on the day when daytime shift water heating operation is performed (step S14). Even if the predicted value of water heating power cannot be directly obtained from the hot water storage type hot water supply device 12, if, for example, the power consumption per unit time of the previous day can be obtained, the actual power consumption per unit time of the previous day may be used as the predicted value of water heating power to estimate the water heating power. This can be applied not only to daytime shift water heating operation but also to estimating the water heating power required for performing gap water heating operation. As the shift water heating setting unit 16-3, the power control unit 16 performs processing to find a time period in which the predicted surplus power per unit time of the day can cover the estimated water heating power amount (see water heating power 21 in Figure 2) (step S15). This processing is illustrated on the left side of Figure 2.

[0027] If no time period is found in which there is predicted surplus power sufficient to cover the estimated amount of water heating power (No in step S15), the shift water heating setting unit 16-3 determines that daytime shift water heating operation will not be performed that day, and proceeds to determining the time period during which water heating is possible in the gap between the water and the boiling water. This is the process shown in the flowchart in FIG. 4. The power control unit 16, functioning as the gap between the water heating control unit 16-5, performs a process to find a time period during which the predicted surplus power for that day will cover the water heating power per unit time (see water heating power 23 in FIG. 2) (step S21 shown in FIG. 4). This is the process exemplified on the right side of FIG. 2. In other words, the gap between the water heating control unit 16-5 determines the surplus power and water heating power related to the gap between the water and the boiling water operation for the same length of time as the determination of the predicted surplus power and water heating power related to the daytime shift water heating operation. If no time slot is found in which the predicted surplus power can cover the estimated amount of water boiling power (No in step S22), the gap water boiling control unit 16-5 determines that gap water boiling operation will not be performed during the daytime on that day and terminates the processing related to daytime shift water boiling operation and gap water boiling operation. On the other hand, if one or more time slots in which the predicted surplus power can cover the estimated amount of water boiling power are found (Yes in step S22), the gap water boiling control unit 16-5 stores the found time slots as available gap water boiling times for that day (step S23). This is because if there is a time slot available for gap water boiling operation on a day when daytime shift water boiling operation is not scheduled, the gap water boiling operation will be performed. The available gap water boiling times can be considered as candidate time slots for performing gap water boiling operation on that day. The processing then proceeds to step S32 in FIG. 5, which will be described later. If it is determined that daytime shift heating operation will not be performed, hot water storage type hot water supply device 12 will heat hot water up to the amount of hot water predicted to be used (target hot water storage amount) through nighttime heating operation. Even if a time available for gap heating is found, if it is determined that daytime shift heating operation will not be performed, hot water storage type hot water supply device 12 will heat hot water up to the amount of hot water predicted to be used (target hot water storage amount) through nighttime heating operation.

[0028] Returning to the explanation of the process shown in FIG. 3, if a time slot in which predicted surplus power sufficient to cover the amount of water-heating power estimated in the determination of step S15 is found (Yes in step S15), the shift water-heating setting unit 16-3 makes the following determination: It determines whether the found time slot is a time slot in which predicted surplus power sufficient to cover the water-heating power is continuous throughout the period during which daytime shift water-heating operation is performed (step S16). Applying this to the example shown on the left side of FIG. 2, the water-heating power 21 required for daytime shift water-heating operation is a period of three consecutive unit hours, and the determination of step S15 determines whether there is a time slot with surplus power sufficient to cover the water-heating power 21 in the first unit hour. Step S16 corresponds to the process of determining whether predicted surplus power sufficient to cover the water-heating power will also be generated in the two time slots following the found time slot.

[0029] If the predicted surplus power sufficient to cover the water heating power is not continuous throughout the period during which daytime shift water heating operation is performed (No in step S16), the shift water heating setting unit 16-3 determines that daytime shift water heating operation will not be performed on that day and proceeds to step S21 in FIG. 4, which relates to determining the available time for gap water heating. This is the process already described. On the other hand, if the predicted surplus power sufficient to cover the water heating power is continuous throughout the period during which daytime shift water heating operation is performed (Yes in step S16), the shift water heating setting unit 16-3 reserves daytime shift water heating operation (step S17). The start time of the found time slot is specified and a request is made to the hot water storage type hot water supply device 12 to perform daytime shift water heating operation. Here, if gap water heating operation will not be performed on the day when daytime shift water heating operation is performed, the process proceeds to the process for that day (processing after daytime shift water heating operation reservation) shown in FIG. 5. However, even on days when daytime shift heating operation is performed, if gap heating operation is performed after the daytime shift heating operation is completed, the time after the reserved time for daytime shift heating operation and within the daytime shift heating possible period is stored in memory as the gap heating possible time until the day (step S18).

[0030] As a modified example, the period from a predetermined time onward within the daytime shift heating available period may be stored in memory as the gap heating available time. For example, if the daytime shift heating available period is from 10:00 to 17:00, the gap heating available time may be from 15:00 onward, i.e., in units of one hour from 15:00 to 17:00. As a further modified example, the entire daytime shift heating available period may be stored in memory as the gap heating available time, and the status of whether or not hot water storage type hot water heater 12 is heating water may be obtained from hot water storage type hot water heater 12 for each hour of the daytime shift heating available period on that day. The time when hot water storage type hot water heater 12 is not heating water is defined as the gap heating available time. After step S18, power control unit 16 proceeds to the processing for that day (processing after daytime shift heating operation reservation) shown in FIG. 5.

[0031] As shown in FIG. 5, power control unit 16, functioning as shift water heating control unit 16-4, monitors whether the daytime shift water heating operation scheduled by the processing of step S17 (see FIG. 3) described above has been canceled by hot water storage type hot water heater 12 (step S31). In other words, it determines whether hot water storage type hot water heater 12 is not performing daytime shift water heating operation even though the scheduled time for daytime shift water heating operation has arrived. Even when the scheduled time slot for daytime shift water heating operation on the day approaches, if there is a sufficient amount of hot water stored in the tank of hot water storage type hot water heater 12, hot water storage type hot water heater 12 may decide not to perform daytime shift water heating operation. This is the cancellation described above. To determine whether a cancellation has occurred, shift water heating control unit 16-4 inquires of hot water storage type hot water heater 12 whether water heating is currently being performed when the scheduled time slot for daytime shift water heating operation arrives. If the heating state is confirmed for a predetermined period or a predetermined number of times or more, it is determined that the daytime shift heating operation is being performed, and otherwise it is determined that it has been canceled.

[0032] If it is determined that the daytime shift water heating operation has not been canceled (No in step S31), and if the system is configured such that gap water heating operation is not performed on the day when the daytime shift water heating operation is performed, the processing for that day is terminated. However, if the system is configured such that gap water heating operation is performed after the daytime shift water heating operation is completed even on the day when the daytime shift water heating operation is performed, the power control unit 16 proceeds to step S46 shown in FIG. 6, which will be described later. On the other hand, if it is determined that the daytime shift water heating operation has been canceled (Yes in step S31), the power control unit 16, functioning as the gap water heating control unit 16-5, waits for the arrival of a gap water heating available time (a loop for No in step S32). This is one or more gap water heating available time periods stored in memory in step S18 (see FIG. 3) or step S23 (see FIG. 4) described above. In the example shown in the lower right of FIG. 2, this corresponds to the process of waiting for the arrival of the time periods of 1:00 PM and 3:00 PM.

[0033] When any of the available gap heating times arrives (Yes in step S32), the gap heating control unit 16-5 further determines the conditions for performing gap heating. First, it checks whether the hot water storage type hot water heater 12 is set to allow daytime heating and is not in manual heating mode, in other words, whether it is in automatic heating mode (step S33). Here, manual heating mode is a mode in which the hot water storage type hot water heater 12 performs heating in response to a user's instruction, so the user's will takes priority. Therefore, there is no room for gap heating. If the setting is such that daytime heating is not performed or if the setting is in manual heating mode (No in step S33), the power control unit 16 proceeds to step S46 in FIG. 6, which will be described later, and determines whether there is a gap heating available time after the current time.

[0034] On the other hand, if the setting allows daytime heating and the automatic heating mode is selected (Yes in step S33), the gap heating control unit 16-5 then determines whether there is currently sufficient surplus power to cover the heating power required for gap heating operation (step S34). This determination is based on the current surplus power, not the predicted surplus power. If there is not sufficient surplus power to cover the heating power (No in step S34), the power control unit 16 proceeds to step S46 in FIG. 6 (described later) and determines whether there is any time after the current time that gap heating is possible. On the other hand, if there is sufficient surplus power to cover the heating power (Yes in step S34), the power control unit 16 requests the hot water storage type hot water heater 12 to start gap heating operation (step S35). Even if the tank of the hot water storage type hot water heater 12 is full and the daytime shift heating operation is canceled, the amount of hot water in the tank may have decreased due to subsequent use, in which case gap heating is performed. Furthermore, when gap heating operation starts, the tank of the hot water storage type hot water heater 12 is already filled with hot water up to the amount predicted to be used, and even if the amount of hot water in the tank increases further due to gap heating operation, no problem occurs and the surplus electricity is still consumed in-house. Also, by performing gap heating after the daytime shift heating operation, the amount of hot water to be heated in the nighttime heating operation from that day onwards can be reduced, which is expected to have the effect of increasing the self-consumption rate of surplus electricity.

[0035] The gap boiling operation can be started, for example, by the gap boiling control unit 16-5 requesting the hot water storage type hot water heater 12 to switch from automatic boiling mode to manual boiling mode via communication. This switch to manual boiling mode is the same as the manual boiling mode set by the user's will as described in step S33 above. However, unlike a switch set by the user's will, this is a process that enables the gap boiling control unit 16-5 to control the boiling of the hot water storage type hot water heater 12. If the hot water storage type hot water heater 12 switches to manual boiling mode in response to the request (Yes in step S36), boiling begins. In other words, execution of the gap boiling operation is initiated. There may be cases where the hot water storage type hot water heater 12 does not switch to manual boiling mode even when requested. In this case (No in step S36), the power control unit 16 abandons the start of gap boiling operation at this time and proceeds to step S46 in FIG. 6 described later, where it determines whether there is any time after the current time that gap boiling is possible.

[0036] When the gap boiling operation has started (Yes in step S36 described above), the gap boiling control unit 16-5 then performs a process to determine when to stop the gap boiling. Specifically, it monitors whether the end of the unit time during which the gap boiling operation started has arrived (step S41 shown in FIG. 6). If the end has not yet arrived and the unit time during which the gap boiling operation started has begun (No in step S41), the process proceeds to step S43 described below, where it is confirmed whether the manual boiling mode of the hot water storage type hot water heater 12 is maintained and the gap boiling operation is possible (step S43). This is because the hot water storage type hot water heater 12 autonomously switches from the manual boiling mode to the automatic boiling mode when the hot water tank becomes full due to manual boiling. If the mode is switched to automatic boiling mode (No in step S43), the gap boiling control unit 16-5 determines that the storage type water heater 12 will autonomously boil water to fill the tank, so that further gap boiling is not possible, and ends the processing for that day.

[0037] On the other hand, if the manual boil-up mode is maintained (Yes in step S43), the gap boil-up control unit 16-5 further determines whether there is currently surplus power sufficient to cover the boil-up power required to execute the gap boil-up operation (step S44). The determination of whether there is currently surplus power sufficient to cover the boil-up power can be made, for example, by sequentially acquiring the amount of power sold or purchased from the power grid 100 while the gap boil-up operation is being executed, and determining that there is no surplus power sufficient to cover the boil-up power if the amount of power purchased continues to exceed a predetermined number. If there is currently surplus power sufficient to cover the boil-up power (Yes in step S44), the process returns to the aforementioned step S41, and the gap boil-up operation continues. On the other hand, if it is determined that there is currently no surplus power sufficient to cover the boil-up power required to execute the gap boil-up operation (No in step S44), the storage-type hot water heater 12 is requested to stop boil-up (step S45). This is the process of stopping the gap boil-up operation. The subsequent processing will be described later.

[0038] Furthermore, if it is determined in the aforementioned step S41 that the end of the unit time at which the gap boiling operation started has arrived (Yes in step S41), the gap boiling control unit 16-5 checks whether the next unit time also belongs to the gap boiling available time (step S42). If the next unit time also belongs to the gap boiling available time (Yes in step S42), the process proceeds to the aforementioned step S43, where it checks whether the manual boiling mode is maintained and gap boiling operation is available. On the other hand, if the next unit time does not belong to the gap boiling available time (No in step S42), the gap boiling control unit 16-5 proceeds to step S45, where it performs processing to stop the gap boiling operation. Then, it checks whether there is any gap boiling available time after the current time (step S46). If it is determined that there is a gap boiling time available after the current time (Yes in step S46), the gap boiling control unit 16-5 returns the process to the above-mentioned step S32 (see FIG. 5) and continues the gap boiling operation. On the other hand, if it is determined that there is no gap boiling time available after the current time (No in step S46), the process ends. The above is an example of the processing executed by the power control unit 16 regarding the daytime shift water heating operation and the gap water heating operation.

[0039] (Embodiment 2) In the first embodiment, the system predicts the predicted surplus power per unit time the day before, stores the available time for gap heating based on the prediction, and determines whether to perform gap heating on the day only during the available time. Because starting and immediately ending gap heating is inefficient, this is prevented by predetermining candidate gap heating times, i.e., the available gap heating times, the same unit time (hour interval) as the daytime shift heating operation the day before. In contrast, in this embodiment, the available gap heating time is not determined the day before. At predetermined time intervals on the day, the system determines whether the current surplus power is sufficient to cover the heating power required to perform gap heating. The predetermined time intervals may be, but are not limited to, the same unit time as the daytime shift heating operation. For example, the predetermined time intervals may be half the length of the daytime shift heating operation. Alternatively, the predetermined time intervals may be 1 / 3, 1 / 4, or the like. In this case, the gap heating control unit 16-5 acquires the surplus power corresponding to the time intervals. However, the time interval for the water heating power that can be obtained from the hot water storage type water heater 12 is fixed, and this is usually the unit time required for the daytime shift water heating operation schedule. In this case, for example, the water heating power corresponding to the time interval can be calculated using a numerical interpolation technique.

[0040] The power control unit 16, functioning as the gap heating control unit 16-5, executes the gap heating operation when it determines that there is surplus power sufficient to cover the heating power required to execute the gap heating operation. In this embodiment, the gap heating operation is executed if the hot water storage type hot water heater 12 is not executing the heating operation on that day. Note that when the gap heating operation starts, the tank of the hot water storage type hot water heater 12 has already been filled with hot water up to the amount predicted to be used. Even if the amount of hot water in the tank increases further due to the gap heating operation, no problem occurs, and the surplus power is still consumed in-house. Furthermore, by executing the gap heating operation after the daytime shift heating operation, the amount of hot water to be heated in the nighttime heating operation on that day can be reduced, which is expected to have the effect of increasing the self-consumption rate of surplus power.

[0041] FIG. 7 corresponds to FIG. 3 of the first embodiment, FIGS. 8 and 9 correspond to FIG. 5 of the first embodiment, and FIG. 10 is a flowchart corresponding to FIG. 6 of the first embodiment. The same processes as those in the first embodiment are given the same reference numerals, so their explanation will be omitted and differences from the first embodiment will be mainly described. FIG. 7 differs from FIG. 3 in that there is no process corresponding to step S18 in FIG. 1. In other words, there is no process for determining and storing the gap boiling possible period on the previous day. Furthermore, the process corresponding to FIG. 4 of the first embodiment has been omitted. This is also a process for storing the gap boiling possible time.

[0042] FIG. 8 also shows the processing of steps S51, S52, and S53, which are not shown in FIG. 5. The processing of S51 and S52 is executed when, even on a day when daytime shift water heating operation is performed, gap water heating operation is executed after daytime shift water heating operation is completed. Power control unit 16, functioning as gap water heating control unit 16-5, monitors whether the scheduled daytime shift water heating operation has been canceled by hot water storage type hot water heater 12 (step S31). This processing monitors whether hot water storage type hot water heater 12 has canceled daytime shift water heating operation without performing it, even when the scheduled time for daytime shift water heating operation has arrived. If it is determined that the scheduled daytime shift water heating operation has been performed without being canceled (No in step S31), power control unit 16, functioning as gap water heating control unit 16-5, monitors whether daytime shift water heating operation is continuing and has not yet completed (step S51).

[0043] If the daytime shift water heating operation has not ended (Yes in step S51), the process proceeds to step S55 shown in Fig. 10 to determine whether there is a time after the current time at which it should be determined whether or not gap water heating operation is possible. On the other hand, if it is determined that the scheduled daytime shift water heating operation has ended (No in step S51), the power control unit 16 as gap water heating control unit 16-5 waits for the start of a unit time at which it should determine whether or not to perform gap water heating operation after the end of the daytime shift water heating operation (a loop of No in step S52). When the start of a unit time at which it should determine whether or not to perform gap water heating operation arrives in the process of step S52, the power control unit 16 as gap water heating control unit 16-5 proceeds to step S33 to determine whether or not it is possible to start executing gap water heating operation in that unit time. On the other hand, if it is determined that the daytime shift heating operation has been canceled (Yes in step S31), the power control unit 16, acting as the gap heating control unit 16-5, waits for the start of the unit time for which it should determine whether or not to perform gap heating operation (No loop in step S53).

[0044] The process of step S53 shown in Fig. 8 is a process that replaces step S32 in Fig. 5 of the first embodiment. That is, instead of determining whether any of the gap boiling possible times stored on the previous day has arrived in the first embodiment, in this embodiment, a determination is made as to whether the start of a predetermined unit time (time interval) for determining whether to perform gap boiling operation has arrived, in other words, whether the timing of a predetermined time interval has arrived. For example, if the period for determining whether to perform gap boiling is from 10:00 to 17:00, and the unit time is one hour, the start of the unit time is 10:00, 11:00, 12:00, ..., 16:00, for a total of seven timings.

[0045] The process of step S53 is similar to the process of step S52 described above. However, the time at which it is determined in step S53 whether to perform the gap heating operation is not necessarily the same as the time at which it is determined in step S52 whether to perform the gap heating operation. For example, if the unit time at which it is determined in step S53 whether to perform the gap heating operation is an hourly unit time from 10:00 to 17:00, the unit time at which it is determined in step S52 whether to perform the gap heating operation may be from 15:00 to 17:00. However, this is just an example and does not exclude the case where both are the same unit time. When the start of the unit time at which it is determined whether to perform the gap heating operation arrives in the process of step S53, the power control unit 16, functioning as the gap heating control unit 16-5, proceeds to step S33 and determines whether it is possible to start the gap heating operation at that unit time.

[0046] The process of step S54 shown in Figure 10 is a process that replaces steps S41 and S42 in Figure 6 of the first embodiment. That is, instead of determining whether the end of the unit time for performing gap boiling has arrived in the first embodiment, in this embodiment, a determination is made as to whether to end the gap boiling operation after waiting for the arrival of a predetermined time interval for determining whether to perform the gap boiling operation (a loop of No in step S54). Also, the process of step S55 shown in Figure 10 is a process that replaces step S46 in Figure 6 of the first embodiment. That is, instead of checking whether there is a time after the current time when gap boiling is possible in the first embodiment, in this embodiment, a determination is made as to whether there is a unit time after the current time when it is necessary to determine whether the execution of the gap boiling operation can be started.

[0047] As described above, in this embodiment, the available time for gap heating is not predicted the day before as in embodiment 1, but rather, at predetermined time intervals on the day, it is determined whether the current surplus power can cover the heating power required to perform gap heating operation. In this embodiment as well, both a configuration in which gap heating operation is not performed on days when daytime shift heating operation is performed, and a configuration in which gap heating operation is performed after the daytime shift heating operation is completed even on days when daytime shift heating operation is performed, are possible.

[0048] (Embodiment 3) In the second embodiment, instead of predicting the available time for gap heating the day before as in the first embodiment, a determination is made at predetermined time intervals on the day to see whether the current surplus power can cover the heating power required to perform gap heating operation. Furthermore, a process for performing gap heating operation after the end of daytime shift heating operation, even on a day when daytime shift heating operation is performed, was also described. In contrast, in this embodiment, if daytime shift heating operation is performed on the same day, gap heating is performed regardless of whether it occurs before or after daytime shift heating operation. Storage-type hot water supply device 12 autonomously stops heating when the hot water tank is full. Therefore, even if gap heating is performed before the scheduled daytime shift heating operation, resulting in more hot water in the tank than predicted at the start of daytime shift heating operation, no problem occurs, and the surplus power is still consumed by the household. In addition, by performing gap heating later than daytime shift heating operation, the amount of water heated during nighttime heating operation from that day onwards can be reduced, which is expected to have the effect of increasing the self-consumption rate of surplus electricity.

[0049] FIG. 11 is a flowchart corresponding to FIG. 7 in embodiment 2. FIG. 11 relating to the processing for the previous day is the same as FIG. 7. FIG. 12 is a flowchart corresponding to FIGS. 8 and 9 in embodiment 2. FIG. 13 is a flowchart corresponding to FIG. 10 in embodiment 2. FIG. 13 is the same as FIG. 10. Processing similar to that in embodiment 2 is given the same reference numerals, so explanations will be omitted and differences from embodiment 2 will be mainly described.

[0050] The processing of steps S61 and S62 shown in FIG. 12 replaces steps S31 and S53 in FIG. 8. In step S31 in FIG. 8, it is determined whether a scheduled daytime shift water heating operation has been canceled. In the second embodiment, if a daytime shift water heating operation is canceled, the daytime shift water heating operation will not be performed on that day or thereafter. Therefore, it is only necessary to determine whether or not gap water heating operation is possible. In contrast, in this embodiment, gap water heating operation is performed if possible even before the daytime shift water heating operation is performed. Therefore, regardless of whether the daytime shift water heating operation has been canceled, it is determined whether or not hot water storage type hot water supply apparatus 12 is not performing water heating operation (step S61). If hot water storage type hot water supply apparatus 12 is not performing water heating (Yes in step S61), the process waits for the start of the unit time for which it should be determined whether or not to perform gap water heating operation to arrive (step S62), and then determines whether or not gap water heating operation is possible. In this embodiment, as in the second embodiment, the time period for determining whether to perform the gap heating operation is set in advance. For example, the time period for determining whether to perform the gap heating operation is from 10:00 to 17:00 on the same day, and the time unit is one hour.

[0051] In step S61, as a result of determining whether or not the hot water storage type water heater 12 is not performing the heating operation, if the result is that the hot water storage type water heater 12 is performing the heating operation (No in step S61), the power control unit 16, functioning as the gap heating control unit 16-5, proceeds to step S55 in FIG. 13. Then, it determines whether or not there is a start point of a unit time after the current time at which it should be determined whether or not the gap heating operation is possible. On the other hand, if the hot water storage type water heater 12 is not performing the heating operation (Yes in step S61), the power control unit 16, functioning as the gap heating control unit 16-5, determines whether the timing for determining whether or not to perform the gap heating operation, i.e., the start point of the unit time, has arrived (step S62). If the timing for determining whether or not to perform the gap heating operation has arrived (Yes in step S62), it proceeds to determining whether or not the conditions for starting the gap heating operation have been satisfied (steps S33 and S34). If not (No in step S62), the process returns to step S61, and the determination of whether or not storage type hot water supply device 12 is not performing the boiling operation is repeated. The above is the flow of the process shown in FIG.

[0052] The processes of steps S63, S64, and S65 shown in FIG. 13 replace steps S54, S43, S44, and S45 in FIG. 10. The process corresponding to step S55 in FIG. 10 is also shown in FIG. 13. When the gap heating operation is started in step S36 shown in FIG. 12 (Yes in step S36), the power control unit 16 serving as the gap heating control unit 16-5 waits for the end of the unit time of the gap heating operation that has started to be executed (loop of No in step S63). When the end of the unit time of the currently executed gap heating operation has arrived (Yes in step S63), the power control unit 16 performs a process to stop the gap heating operation for the hot water storage type water heater 12 (step S64). The process to stop the gap heating operation may include a process to cancel the manual heating mode of the hot water storage type water heater 12. However, if it is determined that the manual boiling mode was set by the user during the unit time, the user's intention may be prioritized and the manual boiling mode may be continued. Between the end of the unit time and the start of the next unit time, at least the gap boiling control unit 16-5 is able to execute the process of step S61 via step S65 and wait for the start of the next unit time in step S62.

[0053] Following the processing of step S64, the power control unit 16, functioning as the gap heating control unit 16-5, determines whether there is a unit time after the current time for which daytime shift heating operation is scheduled or the start of a unit time for which it should be determined whether gap heating operation is possible (step S65). If there is a unit time after the current time for which daytime shift heating operation is scheduled, it is necessary to cancel the manual heating mode of the hot water storage type hot water supply device 12 and switch to the automatic heating mode in which daytime shift heating operation is performed before the start of that unit time. In this case, the determination in step S65 proceeds to Yes. The same applies if there is a unit time after the current time for which it should be determined whether gap heating operation is possible. On the other hand, if there is no unit time after the current time for which daytime shift heating operation is scheduled or the start of a unit time for which it should be determined whether gap heating operation is possible (No in step S65), the processing for that day ends.

[0054] If it is determined in step S65 that there is a unit time after the current time for which daytime shift boiling operation is scheduled or the start of a unit time for which it should be determined whether gap boiling operation is possible (Yes in step S65), the process returns to step S61 shown in FIG. 12. Then, it is determined whether the hot water storage type water heater 12 is not performing boiling operation (including daytime shift boiling operation). If boiling operation is not being performed, it waits for the start of the next unit time and determines whether to perform gap boiling operation. This is the flow of processing in this embodiment.

[0055] As mentioned above, (i) The power control device of this invention is a power control device that controls the power system of a consumer connected to a power grid, including a storage-type hot water heater and a solar power generation device, and is characterized by comprising: a surplus power prediction unit that determines in advance the predicted hourly surplus power from the power generated by the solar power generation device; a heat-up power acquisition unit that acquires the hourly heat-up power used to heat the hot water from the storage-type hot water heater; a shift heat-up setting unit that compares the predicted surplus power with the magnitude of the heat-up power to determine a schedule for daytime shift heat-up operation, including the case where operation is not performed; a shift heat-up control unit that, when the daytime shift heat-up operation is performed, performs the daytime shift heat-up operation by suppressing the amount of heat generated by the prior nighttime heat-up operation; and a gap heat-up control unit that compares the magnitude of the hourly surplus power with the magnitude of the hourly heat-up power to determine whether there is time available for gap heat-up operation, which uses the surplus power to heat water during periods when the daytime shift heat-up operation is not performed, and performs the gap heat-up operation if there is time available.

[0056] Further, preferred embodiments of the present invention will be described. (ii) The gap heating control unit may be configured to determine whether there is time available for gap heating operation using the surplus electricity on a day when the shift heating setting unit has decided not to perform daytime shift heating operation. According to this aspect, gap heating operation can be performed at a time available on the day when no daytime shift heating operation is scheduled.

[0057] (iii) When the storage-type hot water supply device does not perform daytime shift heating operation even though the shift heating setting unit has scheduled the daytime shift heating operation period, the gap heating control unit may be configured to determine whether there is time within the scheduled period during which gap heating operation using the surplus electricity is possible. According to this aspect, even when the scheduled period for daytime shift boiling operation arrives, the hot water storage type hot water supply device can perform gap boiling operation at a possible time on the day when the daytime shift boiling operation is not being performed.

[0058] (iv) The gap heating control unit may determine whether or not there is a time available for gap heating operation after the scheduled daytime shift heating operation has ended. According to this aspect, after the scheduled daytime shift boiling operation is completed, it is determined whether there is time available for gap boiling operation, and if possible, the gap boiling operation can be performed at that time.

[0059] (v) The gap heating control unit may be configured to determine whether there is a time during which the daytime shift heating operation will end and gap heating operation will be possible during a period that overlaps with a period during which the daytime shift heating operation may be scheduled but starts later than the period. According to this aspect, it is determined whether there is a time during a predetermined period on the day when daytime shift boiling operation can be scheduled, which period starts later than that, during which daytime shift boiling operation can end and gap boiling operation can be performed, and if there is such a time, gap boiling operation can be performed during that time.

[0060] (vi) The hourly increments of the surplus power used in determining whether there is time available for the gap heating operation may be the same length as the hourly increments of the predicted surplus power and the heating power used for comparison when scheduling the daytime shift heating operation. According to this aspect, by making the time intervals of the predicted surplus power and the heat-up power compared when scheduling daytime shift heat-up operation the same length as the time intervals of the surplus power used to determine whether there is time available for gap heat-up operation, it becomes easier to determine whether there is time available for gap heat-up operation during times when daytime shift heat-up operation is not being performed.In addition, it is possible to efficiently allocate time for gap heat-up operation during times when daytime shift heat-up operation is not being performed.

[0061] (vii) The shift heating setting unit may schedule the daytime shift heating operation to be performed during a predetermined number of consecutive periods when the magnitude of the predicted surplus power is equal to or greater than the magnitude of the heating power, and the gap heating control unit may determine whether the gap heating operation is possible during at least one period when the daytime shift heating operation is not performed and the magnitude of the surplus power is equal to or greater than the magnitude of the heating power. According to this aspect, daytime shift boiling operation is scheduled for a period of a predetermined number of consecutive times during which the magnitude of the predicted surplus power is equal to or greater than the magnitude of the boiling power, and if there is even one time during which the magnitude of the surplus power is equal to or greater than the magnitude of the boiling power, a determination is made as to whether or not the gap boiling operation is possible at that time.

[0062] (viii) The water-heating power acquisition unit may acquire actual hourly power used for water-heating in the past by the hot water storage type hot water heater, and use this as the water-heating power for the corresponding hourly period. According to this aspect, the heating power of the hot water storage type water heater required when scheduling daytime shift heating operation or determining the time when gap heating operation is possible can be obtained from past performance.

[0063] (ix) The gap heating control unit can obtain from the storage type hot water supply device whether or not the water is being heated, and can sequentially obtain the status of whether or not the storage type hot water supply device is being heated during the period when the daytime shift heating operation is scheduled, and can determine that the storage type hot water supply device is not performing daytime shift heating operation if a status of not being heated is obtained for a predetermined number of consecutive times or more. According to this aspect, the gap heating control unit can determine, for example, whether the hot water storage type hot water supply device has canceled its scheduled daytime shift heating operation on the day by inquiring of the hot water storage type hot water supply device about its status of whether heating is in progress or not.

[0064] (x) The boil-up power acquisition unit may acquire actual hourly power consumption values ​​from the storage-type hot water supply device, and the gap boil-up control unit may use the actual values ​​as the boil-up power, acquire the surplus power of the power system at that time, compare the surplus power acquired at multiple times with the boil-up power at the corresponding time, and determine that the gap boil-up operation can be performed if the surplus power is greater than the boil-up power for a predetermined number of consecutive times or more. According to this aspect, the gap heating control unit can determine whether there is time available to perform gap heating operation by using the surplus power at that time obtained from the power system and the actual value of past heating power obtained from the storage type water heater.

[0065] (xi) The gap boiling control unit can obtain from the storage type hot water supply device whether the storage type hot water supply device is in a state of manual boiling based on a user's instruction, or whether the instruction has not been received or the device is in a state of automatic boiling after manual boiling has ended, and may be configured to perform the gap boiling operation when the storage type hot water supply device is not in a state of manual boiling. According to this aspect, during manual boiling based on the user's instructions, gap boiling operation can be refrained from and the user's wishes can be given priority.

[0066] (xii) The gap boiling control unit may sequentially acquire the amount of electricity sold or purchased from the power grid while the gap boiling operation is being performed, and may stop the gap boiling operation if the amount of electricity purchased continues to be more than a predetermined number of times. According to this aspect, it is possible to detect, by acquiring the amount of purchased power, that there is no surplus power sufficient to cover the heating power while the gap heating operation is being performed.

[0067] (xiii) One aspect of the present invention includes a power control method comprising the steps of: a control unit of a power control device that controls a power system of a consumer connected to a power grid and including a storage-type hot water heater and a solar power generation device; determining in advance predicted hourly surplus power from the power generated by the solar power generation device; obtaining hourly heating power to be used for heating the hot water of the storage-type hot water heater; comparing the predicted surplus power with the magnitude of the heating power to determine a schedule for daytime shift heating operation, including a case where operation is not performed; if the daytime shift heating operation is performed, reducing the amount of heating by prior nighttime heating operation; and comparing the magnitude of the hourly surplus power with the magnitude of the hourly heating power to determine whether there is time available for gap heating operation, which uses the surplus power to heat water during a period when the daytime shift heating operation is not performed, and performing the gap heating operation if there is time available.

[0068] The aspects of the present invention also include combinations of any of the above-described aspects. In addition to the above-described embodiment, various modifications of the present invention are possible. These modifications should not be interpreted as not falling within the scope of the present invention. The present invention should include all modifications and equivalents to the scope of the claims. [Explanation of symbols]

[0069] 10: Power system, 11: Photovoltaic power generation device, 12: Storage type hot water heater, 13-1 to 13-n: Electrical equipment, 14: Power conditioner, 14B: Bidirectional DC / DC converter, 14D: DC / DC converter, 14V: Inverter, 15: HEMS, 16: Power control unit, 16-1: Surplus power prediction unit, 16-2: Heating power acquisition unit, 16-3: Shift heating setting unit, 16-4: Shift heating control unit, 16-5: Gap heating control unit, 17: HEMS server, 18: Power control device, 19: Information terminal, 21, 23: Heating power, 22: Predicted surplus power, 24: Surplus power, 100: Power system, 102: Storage battery

Claims

1. A power control device that controls a power system of a consumer connected to a power grid, the power system including a hot water storage type hot water supply device and a solar power generation device, a surplus power prediction unit that calculates in advance a predicted hourly surplus power of the power generated by the solar power generation device; a water heating power acquisition unit that acquires water heating power used for water heating per hour in the hot water storage type hot water heater; a shift heating-up setting unit that compares the magnitude of the predicted surplus power with the heat-up power and determines a schedule for daytime shift heating-up operation, including a case where operation is not performed; a shift heating control unit that, when performing the daytime shift heating operation, suppresses the amount of water heated in a previous nighttime heating operation and performs the daytime shift heating operation; A power control device comprising: a gap heating control unit that compares the magnitude of hourly surplus power with the hourly heating power, determines whether there is time available for gap heating operation, which uses the surplus power to heat water during periods when the daytime shift heating operation is not performed, and performs the gap heating operation if there is time available.

2. The power control device according to claim 1, wherein the gap heating control unit determines whether there is time available for gap heating operation using the surplus electricity on a day when the shift heating setting unit has decided not to perform the daytime shift heating operation.

3. The power control device of claim 1, wherein the gap heating control unit determines whether there is time within the scheduled period when the storage type hot water supply device does not perform daytime shift heating operation even when the shift heating setting unit has scheduled the daytime shift heating operation, thereby performing gap heating operation using the surplus electricity.

4. The power control device according to claim 1 , wherein the gap boiling control unit determines whether there is a time available for gap boiling operation after the scheduled daytime shift boiling operation has ended.

5. The power control device described in claim 1, wherein the gap heating control unit determines whether there is a time during which the daytime shift heating operation will end and gap heating operation is possible during a period that overlaps with a period during which the daytime shift heating operation may be scheduled but whose start date is later than the period.

6. The power control device described in claim 1, wherein the hourly increments of the surplus power used to determine whether there is time available for the gap heating operation are the same length as the hourly increments of the predicted surplus power and the heating power used to compare when scheduling the daytime shift heating operation.

7. the shift heat-up setting unit, when a predetermined number of consecutive periods during which the magnitude of the predicted surplus power is equal to or greater than the magnitude of the heat-up power, schedules the daytime shift heat-up operation to be performed during those consecutive periods; The power control device described in claim 6, wherein the gap heating control unit determines whether the gap heating operation is possible at that time if there is at least one time when the daytime shift heating operation is not being performed and the magnitude of the surplus power is greater than or equal to the magnitude of the heating power.

8. The power control device described in claim 1, wherein the heating power acquisition unit acquires the actual power used per hour in past heating operations by the storage type water heater from the storage type water heater and uses this as the heating power per hour.

9. The gap heating control unit is capable of obtaining from the storage type hot water supply device whether or not the water is being heated, and sequentially obtains the status of whether or not the storage type hot water supply device is being heated during the period when the daytime shift heating operation is scheduled, and determines that the storage type hot water supply device is not performing daytime shift heating operation if a status of not being heated is obtained for a predetermined number of consecutive times or more.This is the power control device described in claim 1.

10. the water heating power acquisition unit is capable of acquiring an actual value of power consumption per hour from the hot water storage type water heater; The power control device described in claim 1, wherein the gap boiling control unit uses the actual value as the boiling power, obtains the surplus power of the power system at that time, compares the surplus power obtained at multiple times with the boiling power at the corresponding time, and determines that the gap boiling operation can be performed if the surplus power is greater than the boiling power for a predetermined number of consecutive times.

11. A control unit of a power control device that controls a power system of a consumer connected to a power grid, the power system including a storage type hot water supply device and a solar power generation device, calculating in advance a predicted hourly surplus power of the power generated by the solar power generation device; A step of acquiring hourly water heating power used for heating the hot water storage type hot water heater; a step of comparing the magnitude of the predicted surplus power with the boiling power and determining a schedule for daytime shift boiling operation, including a case where operation is not performed; When performing the daytime shift boiling operation, a step of suppressing the amount of boiling in a prior nighttime boiling operation; The power control method includes a step of comparing the magnitude of hourly surplus power with the hourly boiling power, determining whether there is time available for gap boiling operation, which uses the surplus power to boil water during a period when the daytime shift boiling operation is not performed, and performing the gap boiling operation if there is time available.

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