JP2013024487A - Water heater, controller, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water heater that is adaptive to excess electric power varying in energy level and is not apt to run short in hot water supply even when excess electric power is not received from a commercial electric power system, and to provide a controller and a program.SOLUTION: A water heater 1 has a compressor 15 constituted of a first individual compressor 151 and a second individual compressor 152 which are provided side by side. The compressor 15 changes in power consumption in steps depending upon the number of the individual compressors 151, 152 in operation. A controller 7 includes a selection section 71 which selects the individual compressors 151, 152 to be placed in operation in a time zone determined in a schedule as an operation time zone in which the water heater 1 is operated with excess electric power of solar cells, and a schedule storage section 72 which stores the schedule. The selection section 71 selects the individual compressors 151, 152 to be placed in operation so that the power consumption of the water heater 1 becomes maximum within the range of actual excess electric power in the operation time zone.

Description

  The present invention relates to a heat pump type water heater, a control device, and a program.

  Generally, heat pump water heaters are devices that operate and store hot water at midnight, where late-night charges are applied to electricity bills, but when hot water heated up at midnight is used the next night For example, if the hot water storage time becomes longer, the loss due to heat dissipation during that time will increase. Furthermore, since the atmospheric temperature is lower at night than in the daytime, the energy consumption efficiency (COP: Coefficient Of Performance) of the heat pump type hot water heater is lowered.

  By the way, in recent years, even in ordinary homes and the like, a grid interconnection system that supplies power from a solar cell to various loads and supplies power from the commercial power system to the load when the generated power of the solar cell is insufficient is rapidly increasing. Is popular. In the grid-connected system, if the generated power of the solar cell exceeds the power consumption and there is a surplus in the power generated by the solar cell (surplus power), this surplus power flows back to the commercial power system (commercial AC power supply). Can be sold to an electric power company (see, for example, Patent Document 1).

  However, in the future, if reverse flow (power sale) is performed simultaneously from a large number of customers, the power generated by solar cells will have a greater impact on the commercial power system, resulting in a decrease in power quality of the commercial power system. May lead to Therefore, as a method for effectively using the surplus power of the solar cell by a method other than the power sale, it has been proposed to operate the heat pump water heater during the day with the surplus power of the solar cell (for example, non-patent) Reference 1).

  Non-Patent Document 1 extracts a driving pattern that minimizes the average cost for each scenario by using a genetic algorithm (GA) assuming a plurality of scenarios from predicted patterns of power / hot water demand and solar cell output. A technique is disclosed. Thereby, reverse power flow suppression can be aimed at in consideration of the uncertainty of prediction of electric power and hot water supply demand, and the output of a solar cell.

Japanese Patent Laying-Open No. 2003-189477 (paragraphs 0047-0048)

Masahiro Asari, Kenichi Tokoro, "Solar power generation reverse power flow suppression method using interconnection control with customer equipment-Operation planning method of heat pump water heater considering forecast uncertainty", Central Research Institute of Electric Power Industry report (R08025), Central Research Institute of Electric Power Industry, August 2009, p. 1-13

  However, since the amount of heat (heating capacity) generated per unit time is substantially constant in a normal heat pump type water heater, a relatively large electric power (at least 1 kW) is required to operate even during days when the atmospheric temperature is high and the COP is high. Degree) is required. Therefore, if the solar cell does not have enough surplus power to operate the heat pump water heater due to bad weather or high power demand at the load, the heat pump water heater will be The belt cannot be operated, and as a result, hot water may run out.

  In addition, the heat pump water heater can be operated by receiving additional power from the commercial power system (power purchase) for the shortage of power, but in this case, the time when surplus power should normally be generated The band will receive extra power from the commercial power system.

  The present invention has been made in view of the above-described reasons, and corresponds to various amounts of surplus power, and a hot water heater, a control device, and a program that are unlikely to cause hot water shortage without receiving excessive power supply from a commercial power system. The purpose is to provide.

  The hot water supply apparatus of the present invention is a hot water storage type hot water supply apparatus that includes a hot water storage tank that stores hot water and a heat pump type heating device that heats the hot water stored in the hot water storage tank, and supplies hot water using the hot water in the hot water storage tank. The heating device includes a compressor that compresses the refrigerant, and the compressor includes a plurality of individual compressors provided in parallel with each other in the flow path of the refrigerant, depending on the number of operating individual compressors. The power consumption is switched in stages.

  The control device of the present invention includes the water heater and a solar battery, and a consumer who operates the water heater with surplus power obtained by subtracting power consumed by a load other than the water heater from the output of the solar battery. A control device for controlling the operation of the water heater used in the system, the schedule storage unit storing a schedule in which an operating time zone for operating the water heater is operated with the surplus power, and the schedule The size of the surplus power of an individual compressor that is operated from among the plurality of individual compressors so that the power consumption of the hot water heater is maximized within the range of the surplus power during the operation time period determined in And a selection unit that selects according to the above.

  The control apparatus preferably further includes a schedule setting unit that sets the schedule according to an operation input to the user interface and writes the schedule in the schedule storage unit.

  In this control device, the surplus power of the next day is predicted for each time zone, the schedule for the next day is determined with the time zone predicted that the surplus power is equal to or greater than a predetermined value as the operating time zone, and the schedule is It is more desirable to further include a surplus prediction unit that writes to the schedule storage unit.

  A program according to the present invention includes the above-described hot water heater and a solar battery, and operates the hot water heater with surplus power obtained by subtracting power consumed by a load other than the hot water heater from the output of the solar battery. Is a program that is executed by a computer that controls the operation of the water heater, the computer storing a schedule in which an operating time zone in which the water heater is operated with the surplus power is determined. An individual compressor that is operated from among the plurality of individual compressors so that the power consumption of the water heater is maximized within the range of the surplus power during the operation time period determined by the schedule. Is a program for functioning as a selection unit that selects according to the magnitude of the surplus power.

  According to the present invention, since the power consumption is changed in stages depending on the number of operating individual compressors, it corresponds to various amounts of surplus power, and it is difficult to cause hot water shortage without receiving extra power supply from the commercial power system. There are advantages.

It is explanatory drawing which shows the structure of the water heater based on Embodiment 1. FIG. It is explanatory drawing which shows the whole structure of the customer system which concerns on Embodiment 1. FIG. FIG. 6 is an explanatory diagram of an operation of the control device according to the first embodiment. FIG. 10 is an explanatory diagram of an operation on a “sunny” day of the control device according to the second embodiment. It is explanatory drawing of operation | movement of the day of "cloudy" of the control apparatus which concerns on Embodiment 2. FIG.

(Embodiment 1)
As shown in FIG. 2, the water heater 1 of the present embodiment includes a consumer 10 together with a load 4 including a solar cell 2, a power conditioner 3, and various devices (air conditioning, lighting, IH heater, refrigerator, television, dryer, etc.). And constitutes a customer system together with the solar cell 2 and the like. Here, a general detached house will be described as an example of a consumer. However, the present invention is not limited to this, and the present invention can also be applied to an apartment house or a facility as a consumer.

  The solar cell 2 constitutes a power generator that generates direct-current power using natural energy (sunlight). Since the generated electric power of the solar cell 2 fluctuates in accordance with the amount of solar radiation, the solar battery 2 basically generates power during the day and stops generating at night. The solar cell 2 is connected to the power conditioner 3 through a connection box (not shown).

  The power conditioner 3 has an inverter circuit (not shown) that converts DC power from the solar cell 2 into AC power synchronized with the phase of the commercial power system 5. The output of the power conditioner 3 is connected to a distribution board 6 installed in the house, and the power from the solar cell 2 is supplied to the load 4 via the power conditioner 3 and the distribution board 6. The distribution board 6 is also connected to the commercial power system 5. When the total demand power of the load 4 cannot be covered only by the output from the solar battery 2, the load 4 is supplied with power from the commercial power system 5.

  Furthermore, the power conditioner 3 stops the operation of the inverter circuit when the power failure of the commercial power system 5 is detected, and a protective device (not shown) that disconnects the disconnection relay (not shown) inserted between the distribution board 6 and the inverter. (Not shown) to prevent the solar cell 2 from being operated alone. In addition, when the surplus power (hereinafter referred to as “surplus power”) is generated in the generated power of the solar cell 2, the power conditioner 3 reversely flows the surplus power to the commercial power system 5 and sells the power to the power company. It has a function. The surplus power here is the power obtained by subtracting the power consumed by the load 4 from the output of the solar cell 2. The power conditioner 3 is installed in the distribution board 6 or around the distribution board 6.

  The commercial power system 5 is a single-phase three-wire system, and is drawn into a house by a lead-in wire (not shown) consisting of three wires of a neutral electrode and a pair of voltage electrodes, and is connected to a distribution board 6. The distribution board 6 accommodates a main breaker (not shown), a plurality of branch breakers (not shown), and the like, and a load 4 is connected to each branch breaker.

  The water heater 1 is connected to a branch breaker of the distribution board 6 together with other loads 4 and operates by receiving power supply from the solar cell 2 or the commercial power system 5. As shown in FIG. 1, the water heater 1 includes a hot water storage tank 11 that stores hot water and a heating device 12 that heats the hot water stored in the hot water storage tank 11, and supplies hot water using hot water in the hot water storage tank. This is a water heater. The heating device 12 is of a heat pump type and is installed outside the house together with the hot water storage tank 11.

  The hot water storage tank 11 has a forward pipe 111 connected to the bottom, and is connected to an inlet of a heating heat exchanger 13 of the heating device 12 described later via the forward pipe 111. Further, the hot water storage tank 11 has a return pipe 112 connected to an upper portion thereof and is connected to an outlet of the heat exchanger 13 for heating via the return pipe 112. A circulation pump 14 for circulating hot water is provided in the outgoing pipe 111 between the hot water storage tank 11 and the heat exchanger 13 for heating. Thereby, hot water in the hot water storage tank 11 is conveyed from the bottom of the hot water storage tank 11 to the heating heat exchanger 13 through the outgoing pipe 111, heated in the heating heat exchanger 13, and then passed through the return pipe 112 to the hot water storage tank. 11 is returned to the hot water storage tank 11 from the upper part.

  The hot water storage tank 11 is connected to a water supply or the like (not shown) and has a water supply port (not shown) for supplying low-temperature water to the inside, and a hot water supply pipe (not shown) for hot water supply. And a discharge port (not shown) for discharging high-temperature hot water. The hot water storage tank 11 employs a heat insulating structure so that the heat of the internal hot water is not easily released.

  With the above configuration, the hot water storage tank 11 is always filled with hot water, and hot water supplied from the bottom (water supply port) and heated is returned from the top, so that the hot water in the inside becomes higher as it goes upward. Here, a plurality of temperature sensors (not shown) arranged in the vertical direction are provided in the hot water storage tank 11, and the hot water heater 1 has a predetermined temperature (from the upper end of the hot water storage tank 11 to a predetermined temperature (high temperature) by the output of the temperature sensor. For example, it is detected whether the hot water is 90 ° C.) and the amount of hot water is determined. If the amount of hot water in the hot water storage tank 11 has reached a predetermined amount of boiling hot water, the water heater 1 determines that the boiling has been completed, and stops the operation of the heating device 12. The amount of hot water here refers to the amount of hot water in the hot water storage tank 11 that is not lower than a predetermined temperature. The amount of boiling hot water is arbitrarily set by a user or the like by a controller (not shown) of the water heater 1.

The heating device 12 collects heat in the atmosphere in a refrigerant (for example, a natural refrigerant such as CO ₂ ), compresses the refrigerant with the compressor 15 to a high temperature, and then heats the refrigerant in the heat exchanger 13 for heating. Hot water is heated by transmitting to hot water.

  More specifically, the heating device 12 includes an atmospheric heat exchanger 16 that transmits atmospheric heat to the refrigerant, a compressor 15 that compresses the refrigerant, and a heating heat exchanger 13 that transfers the heat of the refrigerant to hot water. And an expansion valve 17. The atmospheric heat exchanger 16 exchanges heat between the atmosphere and the refrigerant, and takes heat in the atmosphere into the refrigerant. The compressor 15 heats the refrigerant by adiabatically compressing the refrigerant discharged from the atmospheric heat exchanger 16. The heating heat exchanger 13 takes in the refrigerant compressed by the compressor 15, performs heat exchange between the refrigerant and hot water sent from the hot water storage tank 11, and heats the hot water stored in the hot water storage tank 11. The expansion valve 17 expands the refrigerant discharged from the heating heat exchanger 13 and sends it to the atmospheric heat exchanger 16.

  In short, the heating device 12 circulates the refrigerant in the order of the atmospheric heat exchanger 16 → the compressor 15 → the heating heat exchanger 13 → the expansion valve 17 → the atmospheric heat exchanger 16. Thus, the refrigerant absorbs heat in the atmosphere by the atmospheric heat exchanger 16, is compressed by the compressor 15 to become high temperature and high pressure, radiates heat by the heating heat exchanger 13, and is decompressed by the expansion valve 17. Then, it returns to the atmospheric heat exchanger 16. Therefore, the heating device 12 can heat the hot water sent from the hot water storage tank 11 by the heat exchanger 13 for heating.

  By the way, although a general heat pump type hot water heater has only one compressor, the heat pump type hot water heater 1 of the present embodiment includes a plurality of individual compressors in which the compressors 15 individually operate. In the example of FIG. 1, the compressor 15 is composed of two individual compressors, a first individual compressor 151 and a second individual compressor 152.

  The plurality of (two in this case) individual compressors 151 and 152 are provided in parallel with each other in the refrigerant flow path between the atmospheric heat exchanger 16 and the heating heat exchanger 13. . Accordingly, the heating device 12 can operate only one of the first and second individual compressors 151 and 152, or can operate both the first and second individual compressors 151 and 152 simultaneously. it can.

  Here, in the compressor 15 as a whole, the power consumption is switched in stages depending on the number of operating individual compressors 151 and 152, and the amount of heat (heating capacity) generated per unit time is also switched in stages. That is, as the number of operating individual compressors 151 and 152 increases, the heating device 12 increases the power consumption of the compressor 15 as a whole, but increases the amount of heat given to hot water per unit time, and boiles the same amount of water. It takes less time to complete.

  In the present embodiment, it is assumed that each of the plurality of individual compressors 151 and 152 constituting the compressor 15 has the same heating capacity and the same rated power consumption (each 0.5 kW). However, the plurality of individual compressors 151 and 152 constituting the compressor 15 may have different heating capacities, and in this case, the heating device 12 can be used for power consumption or per unit time depending on the individual compressors 151 and 152 to be operated. The amount of heat given to hot water is different. Moreover, the compressor 15 should just be the structure which consists of several separate compressors, and may have three or more separate compressors.

  Here, the consumer system of the present embodiment has surplus power in at least a part of a time zone in which surplus power is generated by subtracting the power consumed by the load 4 other than the water heater 1 from the output of the solar cell 2. The surplus power is effectively utilized by operating the water heater 1 at. That is, in this customer system, the water heater 1 is operated not only at midnight but also during the day when surplus power is generated in the solar cell 2.

  As shown in FIG. 1, the customer system includes a control device 7 that controls the operation of the water heater 1. In the present embodiment, the control device 7 is provided integrally with the water heater 1 and controls the operation of the circulation pump 14 and the compressor 15. However, the control device 7 may be provided separately from the water heater 1, and may be provided integrally with the power conditioner 3, for example, or provided in a home server (not shown). Good. In FIG. 1, control signal lines are indicated by dotted lines.

  The control device 7 includes a selection unit 71 that selects the individual compressors 151 and 152 to be operated in a time period determined by the schedule as an operation time period for operating the water heater 1 with surplus power, and a schedule storage for storing the schedule. Part 72. The control device 7 includes a computer having a CPU (Central Processing Unit) and a memory as main components, and implements functions as a selection unit 71 and a schedule storage unit 72 by executing a predetermined program.

  When the current time measured by the clock unit (not shown) of the control device 7 is the start time of the operation time zone, the selection unit 71 sets a plurality of individual compressors to be operated according to the amount of surplus power at that time. The individual compressors 151 and 152 are selected. Here, the selection part 71 is monitoring the electric power generation output of the solar cell 2, and the power consumption in the load 4, and calculates | requires the magnitude | size of actual surplus electric power by taking the difference of both. The selection unit 71 selects the individual compressors 151 and 152 to be operated so that the power consumption of the water heater 1 is maximized within the obtained surplus power range. In addition, since the water heater 1 uses electric power even in the circulation pump 14 and the like, the selection unit 71 not only consumes power in the compressor 15 but also makes the power consumption of the entire water heater 1 fall within the range of surplus power. Individual compressors 151 and 152 to be operated are selected. However, in the following description, it is assumed that the power consumption of the water heater 1 other than the compressor 15 is negligible.

  In the present embodiment, the plurality of (two) individual compressors 151 and 152 have the same heating capacity and the same rated power consumption (each 0.5 kW). Only the number of operating individual compressors is determined according to the size. That is, if the number of operating individual compressors is one, the water heater 1 does not change the overall power consumption even if the first and second individual compressors 151 and 152 are operated. 71 substantially selects the number of operating units from 0, 1 and 2. On the other hand, when the heating capacities (rated power consumption) are different among a plurality of individual compressors, the selection unit 71 determines which individual compressors to operate in addition to the number of individual compressors to be operated. Become.

  Here, since the surplus power fluctuates even in the operation time zone, the selection unit 71 operates according to the actual surplus power at any time so as to follow the fluctuation of the surplus power in the operation time zone. Individual compressors 151 and 152 are selected. In short, when the surplus power changes in the operating time zone, the selection unit 71 selects the individual compressors 151 and 152 to be operated so that the power consumption of the water heater 1 becomes maximum within the range of the surplus power after the change.

  The schedule memory | storage part 72 has memorize | stored beforehand the schedule by which the time zone which operates the water heater 1 with surplus electric power was defined as an operation time zone. The schedule stored in the schedule storage unit 72 is a daytime period during which the generated power of the solar cell 2 exceeds the power consumption of the load 4 and the surplus power of the solar cell 2 becomes relatively large (for example, the time between 9 and 14:00) ) Is defined as the operating hours.

  However, the generated power of the solar cell 2 in each time zone varies depending on the season, and the power consumption in the load 4 in each time zone also varies depending on the day of the week and the season. Therefore, the time when surplus power is actually generated with only one type of schedule. There may be a gap between the time zone and the operating time zone. Therefore, the control device 7 has a calendar function including information on the day of the week and season (month), and stores the schedule for each day of the week and season in the schedule storage unit 72, so that it is applied according to the day of the week and the season. The schedule may be changed automatically.

  In the present embodiment, the control device 7 further includes a schedule setting unit 73 that sets a schedule according to an operation input to the user interface and writes the schedule in the schedule storage unit 72. Here, the user interface is, for example, a controller of the water heater 1, and a user or an administrator of the customer system (hereinafter referred to as “user etc.”) can arbitrarily rewrite the schedule by operating the user interface. . Therefore, the user etc. can determine an operation time zone according to the actual power value of the generated power of the solar cell 2 and the power consumption of the load 4 in each customer 10, and can set a schedule.

  Furthermore, the schedule memorize | stored in the schedule memory | storage part 72 operates the water heater 1 also in the night (midnight) when the generated electric power does not arise in the solar cell 2 in addition to the daytime operation time zone as mentioned above. The time zone (hereinafter referred to as “night operation hours”) is fixed. Here, the ratio between the daytime operation time zone and the nighttime operation time zone is set in advance, for example, 3: 7 (= daytime: nighttime).

  In the nighttime operating hours, no surplus power is generated in the solar cell 2, so that the water heater 1 operates by receiving power supply from the commercial power system 5. Therefore, the selection unit 71 operates the predetermined individual compressors 151 and 152 regardless of the amount of surplus power during the night operation hours. In the present embodiment, the selection unit 71 operates both the first and second individual compressors 151 and 152 during the night operating hours.

  Note that when the water heater 1 is in the boiling-up completed state, the control device 7 stops the compressor 15 even in the operation time zone or the night operation time zone.

  Next, operation | movement of the control apparatus 7 comprised as mentioned above is demonstrated with reference to FIG. 3 which shows the electric power fluctuation of 1 day (24 hours) in the consumer 10. FIG. In FIG. 3, the horizontal axis is the time axis and the vertical axis is the electric power, (a) is the generated power of the solar cell 2, (b) is the power consumption of the load 4 other than the water heater 1, and (c) is the water heater 1. Power consumption, (d) represents the power sales power when the water heater 1 is not present, and (e) represents the power sales power when the water heater 1 is present. In addition, since the sold power is a power that flows backward to the commercial power system 5 as viewed from the consumer, the sold power is represented as negative power in FIG.

  That is, the control device 7 receives supply of power from the commercial power system 5 (power purchase) during the time period from time t1 to time t2 that is determined as the nighttime operation time zone in the schedule, and the first and second individual devices Both compressors 151 and 152 are operated. Thereby, in the time slot | zone of the time t1-t2 in FIG. 3, about 1.0 kW (= 0.5 kWx2) power consumption generate | occur | produces in the water heater 1. FIG.

  Thereafter, the solar cell 2 starts generating power at time t3 in FIG. 3, and surplus power is generated at time t4 because the generated power of the solar cell 2 exceeds the power consumption of the load 4. If there is no hot water heater 1, all generated surplus power is reversely flowed to the commercial power system 5 to be sold power, so that sold power as shown in FIG. 3 (d) is generated.

  On the other hand, in this embodiment, the control apparatus 7 operates the water heater 1 with surplus electric power during the time period from time t5 to t6 determined as the operation time period in the schedule. Here, the control device 7 operates only the first individual compressor 151 so that the power consumption of the water heater 1 is maximized within the range of surplus power. Therefore, in the time period from time t5 to t6 in FIG. 3, compared with the case where there is no hot water heater 1, the electric power sold is less than the power consumption (about 0.5 kW) of the hot water heater 1 as shown in (e). It gets smaller by the minute.

  Thereafter, at time t7 in FIG. 3, the generated power of the solar cell 2 falls below the power consumption of the load 4, so that the surplus power disappears, and at time t8, the solar cell 2 stops generating power.

  According to the consumer system of the present embodiment described above, the power generated by the solar cell 2 is basically supplied to the load 4, and when surplus power is generated in the solar cell 2, the surplus power is supplied to the hot water supply. Used as power for the heating device 12 of the machine 1. Therefore, the surplus electrical energy (surplus power) generated in the solar cell 2 is effectively used by a method other than backflowing into the commercial power system 5 and selling it to the power company. Therefore, in the configuration of the present embodiment, power selling due to the reverse power flow of surplus power is suppressed, and the influence of the power generated by the solar cell 2 on the commercial power system 5 is reduced. 5 can be suppressed.

  Further, in this case, the hot water heater 1 operates even during the day when surplus power is generated in the solar cell 2, so that the hot water boiled during the day is used on the evening of the day as compared with the case where the hot water is operated and stored at midnight. As a result, the hot water storage time is shortened, and the loss due to heat dissipation during that time can be reduced. Furthermore, since the atmospheric temperature is higher during the day than at midnight, the heat pump type hot water heater 1 has an advantage that the energy consumption efficiency (COP: Coefficient Of Performance) is increased by operating during the day.

  In addition, since the compressor 15 includes a plurality of individual compressors 151 and 152 in the water heater 1 of the present embodiment, the power consumption of the compressor 15 can be switched in stages depending on the number of operating individual compressors 151 and 152. Thereby, the water heater 1 can operate only some of the individual compressors 151 and 152 even when the surplus power sufficient to operate all the individual compressors 151 and 152 is not generated in the solar cell 2. . Therefore, even when sufficient surplus power does not occur in the solar cell 2 due to bad weather or a large demand for power at the load 4, the water heater 1 can be operated in a time zone to be operated, As a result, it is possible to avoid hot water shortage (the amount of hot water in the hot water storage tank 11 falls below the lower limit).

  Furthermore, the control device 7 can cover the power of the water heater 1 with only the surplus power by determining the number of operating individual compressors 151 and 152 within a range where the power consumption of the water heater 1 does not exceed the surplus power. . That is, the control device 7 is additionally provided from the commercial power system 5 in order to operate the water heater 1 by limiting the individual compressors 151 and 152 to be operated even when the surplus power is not generated in the solar cell 2. It is possible to avoid receiving power supply (power purchase). Therefore, the hot water heater 1 can cope with surplus power of various sizes, and even without receiving extra power supply from the commercial power system 5, it is difficult for hot water to run out.

  A storage battery (not shown) may be added to the consumer system as described above. The storage battery is connected to the power conditioner 3, and charging / discharging is controlled by the power conditioner 3. In this case, since the storage battery can store as electric energy the amount obtained by subtracting the power consumption of the water heater 1 from the surplus power of the solar battery 2, it is possible to further suppress the power sale due to the reverse power flow of the surplus power.

  By the way, in this embodiment, the power conditioner 3 has a function of selling surplus power back to the commercial power system 5 to sell power, but such a function for selling power is not essential. That is, with the further spread of solar cells and the like in the future, there is a view that power sales will be regulated from the viewpoint of stabilizing the power quality of the commercial power system 5, and in the future surplus of solar cells It is also possible that power cannot be sold freely. If the surplus power can no longer be sold, the surplus power will be discarded or stored in the storage battery, but even if stored in the storage value, the remaining power will be discarded if the storage battery is fully charged. As a result, power is wasted eventually.

  On the other hand, according to the customer system of the present embodiment, surplus power of the solar cell 2 is effectively used as power for the heating device 12 of the water heater 1, so that originally wasted power is sold. It can be used effectively by other methods. In other words, according to the configuration of the present embodiment, not only power selling due to a reverse power flow of surplus power can be suppressed and a reduction in power quality of the commercial power system 5 can be suppressed, but also surplus even in a situation where power cannot be sold. The effect that electric power can be used effectively is also produced.

(Embodiment 2)
In the present embodiment, the schedule is fixedly set by the schedule setting unit 73 in that the control device 7 dynamically determines a schedule (operation time zone) for operating the water heater 1 with surplus power. 1 and different. Hereinafter, configurations similar to those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and description thereof is omitted as appropriate.

  In the present embodiment, the control device 7 includes a surplus prediction unit (not shown) that predicts the surplus power of the next day for each time period and determines the next day's schedule based on the prediction result. The surplus prediction unit has a function of holding the actual value of the power consumption of the load 4 for a certain period in the past as history data, and a function of connecting to a server that transmits information such as a weather forecast via the Internet. The surplus prediction unit predicts the next day's power demand (power consumption of load 4) from the historical data by time zone, and forecasts the generated power of the solar cell 2 by the next day from the next day's weather forecast by time zone. And the surplus power of the next day is predicted according to the time zone from the generated power. The starting point of “next day” may be the time when the date changes (0:00), but may also be another time. In this embodiment, application of a late-night charge starts as an electricity charge. Assume that time is 00 minutes.

  The surplus prediction unit predicts the surplus power of the next day for each time zone as described above at a predetermined time (for example, 22:59) every day, determines the next day's schedule based on the prediction result, and stores the schedule. The schedule stored in the unit 72 is rewritten. Here, the surplus prediction unit determines a schedule for the next day using an operation time zone as a time zone in which surplus power is predicted to be equal to or greater than a predetermined value. The predetermined value here is a value larger than the rated power consumption (0.5 kW) per unit of the individual compressors 151 and 152 so that at least one of the individual compressors 151 and 152 can be operated with surplus power. (For example, 0.7 kW).

  However, if the water heater 1 is in the boiling completion state, the control device 7 does not need to operate the water heater 1 any more, no matter how much surplus power is generated. For this reason, the surplus prediction unit does not set all of the time zones in which the surplus power is expected to be on the default value as operating hours, but only a part of the time zone in which the surplus power is expected to be on the default value. The operating hours are assumed. Here, as the surplus power increases, the number of operating individual compressors 151 and 152 increases in the water heater 1, and thus the time required for completion of boiling increases. Therefore, the surplus prediction unit sets the operation time period shorter as the expected surplus power is larger.

  Next, operation | movement of the control apparatus 7 comprised as mentioned above is demonstrated with reference to FIG. 4, 5 which shows the electric power fluctuation | variation for 1 day (24 hours) in the consumer 10. FIG. Here, FIG. 4 shows power fluctuations on a “sunny” day, and FIG. 5 shows power fluctuations on a “cloudy” day. 4 and 5, the horizontal axis is the time axis and the vertical axis is power, (a) is the generated power of the solar cell 2, (b) is the power consumption of the load 4 other than the water heater 1, and (c) is the water heater. 1 shows power consumption, (d) shows power sales power when there is no hot water heater 1, and (e) shows power sales power when there is a water heater 1. In addition, since the sold power is a power that flows backward to the commercial power system 5 as viewed from the consumer, FIGS. 4 and 5 represent the sold power as negative power.

  First, in both “sunny” and “cloudy”, the control device 7 receives the supply of power from the commercial power system 5 during the time period from the time t1 to the time t2 determined as the nighttime operating time zone in the schedule. Electric), both the first and second individual compressors 151 and 152 are operated. Thereby, in the time slot | zone of the time t1-t2 in FIG. 4, 5, about 1.0 kW (= 0.5 kWx2) power consumption generate | occur | produces in the water heater 1. FIG.

  Thereafter, the solar cell 2 starts generating power at time t3 in FIGS. 4 and 5, and surplus power is generated at time t4 because the generated power of the solar cell 2 exceeds the power consumption of the load 4. If there is no hot water heater 1, all generated surplus power is reversely flowed into the commercial power system 5 to become sold power, so that sold power as shown in FIGS. 4 and 5 is generated. 4 and 5, the power consumption of the load 4 is the same, but the day of “sunny” (FIG. 4) has more solar radiation than the day of “cloudy” (FIG. 5). Since the generated power is large, the surplus power generated is also large.

  In the present embodiment, the control device 7 operates the water heater 1 with surplus power during each of the time periods t5 to t6 and t7 to 8 that are defined as operating hours in the schedule. Here, the control device 7 operates only the first individual compressor 151 so that the power consumption of the water heater 1 is maximized within the range of surplus power.

  However, as described above, surplus power is greater on a “sunny” day than on a “cloudy” day, so in a schedule, a “sunny” day (FIG. 4) is a “cloudy” day (see FIG. 4). The operation time zone is set shorter than 5). Here, the day of “clear” (FIG. 4) is set shorter than the day of “cloudy” (FIG. 5) in the operation time zones at times t5 to t6 and t7 to t8.

  In addition, since the surplus power generated is relatively large on a “sunny” day, the control device 7 operates both the first and second individual compressors 151 and 152. Therefore, in each of the time periods t5 to t6 and t7 to 8 in FIG. 4, compared with the case where there is no hot water heater 1, the electric power sales power is the power consumption (about approx. 1.0kW).

  On the other hand, since the surplus power generated is relatively small on the day of “cloudy”, the control device 7 operates only the first individual compressor 151. Therefore, in each time slot | zone of the time t5-t6 in FIG. 5, t7-8, compared with the case where there is no hot water heater 1, electric power selling electric power is the power consumption (about approx. 0.5kW). That is, the operating number of the individual compressors 151 and 152 in the operating time zone of the water heater 1 is different between the day of “sunny” and the day of “cloudy”.

  Thereafter, in any of FIGS. 4 and 5, the generated power of the solar cell 2 falls below the power consumption of the load 4 at time t <b> 9, so that the surplus power disappears, and the solar cell 2 stops generating power at time t <b> 10. .

  According to the configuration described above, the control device 7 predicts the surplus power of the next day by time zone in the surplus prediction unit, and determines the next day's schedule based on the prediction result, and therefore always sets an appropriate schedule. be able to. That is, the hot water heater 1 can supply extra power from the commercial power system 5 as compared to the case where the water heater 1 is controlled according to a fixed schedule without performing weather forecast or power demand prediction as in the first embodiment. It is hard to receive, and it becomes hard to produce out of hot water. Therefore, the control device 7 according to the present embodiment can flexibly cope with a change in the schedule even when the time zone in which surplus power is generated changes due to weather collapse or changes in power demand at the customer 10. Can do.

  Other configurations and functions are the same as those of the first embodiment.

DESCRIPTION OF SYMBOLS 1 Water heater 11 Hot water storage tank 12 Heating device 2 Solar cell 7 Control apparatus 71 Selection part 72 Schedule memory | storage part 73 Schedule setting part 15 Compressor 151 1st separate compressor 152 2nd separate compressor

Claims (5)

A hot water storage tank that stores hot water and a heat pump type heating device that heats the hot water stored in the hot water storage tank, and supplies hot water using hot water in the hot water storage tank;
The heating device has a compressor for compressing the refrigerant,
The hot water heater is characterized in that the compressor includes a plurality of individual compressors provided in parallel with each other in the flow path of the refrigerant, and the power consumption is switched in stages depending on the number of the individual compressors operating. A consumer system comprising the hot water heater according to claim 1 and a solar battery, wherein the hot water heater is operated with surplus power obtained by subtracting power consumed by a load other than the hot water heater from the output of the solar battery. A control device used to control the operation of the water heater,
A schedule storage unit storing a schedule in which an operating time zone for operating the water heater with the surplus power is determined;
An individual compressor that is operated from among the plurality of individual compressors so that the power consumption of the water heater is maximized within the range of the surplus power during the operation time period determined in the schedule. A control device comprising: a selection unit that selects according to size.   The control apparatus according to claim 2, further comprising a schedule setting unit that sets the schedule according to an operation input to a user interface and writes the schedule in the schedule storage unit.   The surplus power of the next day is predicted for each time zone, the schedule for the next day is determined with the time zone in which the surplus power is predicted to be greater than or equal to a predetermined value as the operating time zone, and the schedule is written to the schedule storage unit The control device according to claim 2, further comprising a surplus prediction unit. A consumer system comprising the hot water heater according to claim 1 and a solar battery, wherein the hot water heater is operated with surplus power obtained by subtracting power consumed by a load other than the hot water heater from the output of the solar battery. A program that is used and executed by a computer that controls the operation of the water heater;
The computer,
A schedule storage unit storing a schedule in which an operating time zone for operating the water heater with the surplus power is determined;
An individual compressor that is operated from among the plurality of individual compressors so that the power consumption of the water heater is maximized within the range of the surplus power during the operation time period determined in the schedule. A program to function as a selection part to select according to size.

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