JP2023166859A - heat pump water heater - Google Patents

Abstract

To provide a heat pump water heater which is advantageous in accurately controlling a heat quantity remaining in a hot water storage tank.SOLUTION: A heat pump water heater according to an embodiment includes heating means having a heat pump cycle for heating water and capable of changing heating capability, a hot water storage tank, and control means for controlling boiling-up operation for making hot water heated by the heating means flow into the hot water storage tank. The control means ends the boiling-up operation when a boiling-up quantity which is a heat quantity generated by the boiling-up operation reaches a target boiling-up quantity. The control means decreases a target boiling-up quantity on the day when heating capability on the day which is heating capability of the boiling-up operation on the day is larger than past heating capability which is a leaning value of heating capability of the boiling-up operation in a past prescribed period than when the heating capability on the day is smaller than the past heating capability.SELECTED DRAWING: Figure 3

Description

The present disclosure relates to a heat pump water heater.

Patent Document 1 listed below discloses a hot water storage type electric water heater that changes the boiling temperature for the day based on the difference between the amount of hot water remaining at a predetermined temperature in a hot water storage tank and a predetermined value.

Japanese Patent Application Publication No. 2-166346

In the method disclosed in Patent Document 1, the amount of heat remaining in the hot water storage tank may not always be accurately controlled.

The present disclosure has been made to solve the above-mentioned problems, and an object of the present disclosure is to provide a heat pump water heater that is advantageous in precisely controlling the amount of heat remaining in a hot water storage tank.

A heat pump water heater according to the present disclosure has a heat pump cycle that heats water, and includes a heating means that can change heating capacity, a hot water storage tank, and a boiling operation that causes hot water heated by the heating means to flow into the hot water storage tank. A heat pump water heater comprising: a control means for controlling the boiling operation; If the current heating capacity, which is the heating capacity of the boiling operation on that day, is larger than the past heating capacity, which is the learning value of the heating capacity of the boiling operation in the past predetermined period, the current heating capacity is greater than the past heating capacity. Compared to a smaller case, the target boiling amount for the day is made smaller.

According to the present disclosure, it is possible to provide a heat pump water heater that is advantageous in accurately controlling the amount of heat remaining in the hot water storage tank.

1 is a diagram showing a heat pump water heater according to Embodiment 1. FIG. FIG. 3 is a diagram showing flows of water and refrigerant during boiling operation in the heat pump water heater according to the first embodiment. It is a flow chart showing an example of processing when the water heater control device calculates the target boiling amount for the day. FIG. 2 is a schematic cross-sectional view of a building in which a heat pump water heater according to a second embodiment is installed.

Embodiments will be described below with reference to the drawings. Common or corresponding elements in each figure are denoted by the same reference numerals, and description thereof will be simplified or omitted. In the following description, descriptions such as "water", "hot water", "warm water", "hot water", etc. basically mean liquid water, and can include anything from cold water to hot water.

Embodiment 1.
FIG. 1 is a diagram showing a heat pump water heater according to a first embodiment. In the present embodiment, the calorific value of hot water is calculated as, for example, the difference between the calorific value of water at the same temperature as the water supplied from the water source. Furthermore, in this embodiment, when describing the calorific value of hot water, in principle, the calorific value of hot water is described using the unit of hot water volume [L] when converted to the calorific value of hot water at a predetermined standard hot water supply temperature. The value of the reference hot water supply temperature may be, for example, 40°C.

As shown in FIG. 1, the heat pump water heater of this embodiment is a hot water storage type heat pump water heater that includes a heat pump unit 100 corresponding to a heating means for heating water, and a hot water storage unit 200 having a hot water storage tank 11. be. The heat pump unit 100 and the hot water storage unit 200 are connected via pipes 16a and 16k through which water passes, and electrical wiring (not shown). The heat pump water heater of this embodiment may be, for example, a home-use one or a commercial-use one used in a store or facility.

The heat pump unit 100 includes devices such as a compressor 1, a water/refrigerant heat exchanger 2, an expansion valve 3, and an air heat exchanger 4, and operates using electric power. These devices are connected in an annular manner by piping and the like, and constitute a refrigerant circuit 101 in which the compressor 1 circulates refrigerant. The refrigerant circuit 101 corresponds to a heat pump cycle that heats water. The water-refrigerant heat exchanger 2 exchanges heat between water and a refrigerant, and has an inlet and an outlet for water. In the following description, the hot water heated by the heat pump unit 100 may be referred to as "heated water." The water-refrigerant heat exchanger 2 heats the water that flows in through the inlet with a refrigerant, and causes the heated water to flow out through the outlet. Moreover, the air heat exchanger 4 exchanges heat between air and refrigerant. The heat pump unit 100 further includes a fan 5 that blows outside air to the air heat exchanger 4.

In addition to the hot water storage tank 11, the hot water storage unit 200 includes a circulation pump 6a, a reheating pump 6b, a switching valve 7, a switching valve 8, a switching valve 9, a mixing valve 10, and the like. The circulation pump 6a circulates water (including heated water) through a hot water storage circuit 201 and a reheating circuit 202, which will be described later, and sends the water toward the inlet of the water-refrigerant heat exchanger 2. The circulation pump 6a constitutes a part of the hot water storage circuit 201 and the reheating circuit 202. The reheating pump 6b sends water from a bathtub (not shown) toward the reheating heat exchanger 12. The switching valve 7 is constituted by, for example, an electromagnetically driven four-way valve having four ports: an A port, a B port, a C port, and a D port. The switching valve 7 constitutes a switching mechanism that switches the flow path of heated water flowing out from the outlet of the water-refrigerant heat exchanger 2 to the switching valve 8 and the low-temperature water return port 11e located at the lower part of the hot water storage tank 11. There is. Further, the switching valve 7 constitutes a switching mechanism that returns the hot water flowing out from the high temperature water outlet 11a in the upper part of the hot water storage tank 11 to the low temperature water return port 11e.

The switching valve 8 is constituted by, for example, an electromagnetically driven four-way valve having four ports: an E port, an F port, a G port, and an H port. The switching valve 8 connects the flow path of the water flowing in from the E port to the reheating return port 11c located at the intermediate height of the hot water storage tank 11 and the high temperature water outflow port 11b located at the top of the hot water storage tank 11 for reheating heat exchange. It constitutes a switching mechanism for switching to the device 12. The switching valve 9 is constituted by, for example, an electromagnetically driven three-way valve having three ports: an I port, a J port, and a K port. The switching valve 9 controls the flow path state in which water flowing out from the water intake 11f at the bottom of the hot water storage tank 11 passes through the circulation pump 6a and flows into the water-refrigerant heat exchanger 2, and the flow path state in which water flows out from the reheating heat exchanger 12. It constitutes a switching mechanism that switches between a flow path state in which water passes through the circulation pump 6a and flows into the water-refrigerant heat exchanger 2.

The mixing valve 10 has three ports: an L port, an M port, and an N port. The mixing valve 10 mixes or selects the medium-temperature water taken out from the medium-temperature water outlet 11d located at the intermediate height of the hot water storage tank 11 and the low-temperature water from the water supply end connected to the water source. to flow out to. The hot water storage tank 11 stores heated water. The hot water storage tank 11 is located at the lower part of the hot water storage tank 11, in addition to the high temperature water outlet 11a, the high temperature water inlet 11b, the reheating return port 11c, the medium temperature water outlet 11d, the low temperature water return port 11e, and the water intake 11f. It is equipped with a water supply port 11g. The water supply port 11g is connected to the water supply end via a pipe 16p. Low-temperature water supplied from the water supply end flows into the hot water storage tank 11 through the pipe 16p.

The outlet of the water-refrigerant heat exchanger 2 is connected to the A port of the switching valve 7 via a pipe 16a. The B port of the switching valve 7 is connected to the E port of the switching valve 8 via a pipe 16b. The F port of the switching valve 8 is connected to the high temperature water outlet 11a via a pipe 16c and a pipe 16d. Further, the F port is connected to the primary side inlet of the reheating heat exchanger 12 via piping 16c and piping 16e. The primary side outlet of the reheating heat exchanger 12 is connected to the J port of the switching valve 9 via a pipe 16f. Further, the primary side outlet of the reheating heat exchanger 12 is connected to a flow path connecting the medium temperature water outlet 11d and the L port of the mixing valve 10 via a pipe 16g. The I port of the switching valve 9 is connected to the water intake 11f via a pipe 16h. The K port of the switching valve 9 is connected to the suction port of the circulation pump 6a via a pipe 16j. A discharge port of the circulation pump 6a is connected to an inlet of the water-refrigerant heat exchanger 2 via a pipe 16k. Further, the discharge port of the circulation pump 6a is connected to the C port of the switching valve 7 via a pipe 16l. The D port of the switching valve 7 is connected to the low temperature water return port 11e via a pipe 16m. The H port of the switching valve 8 is connected to the high temperature water inlet 11b via a pipe 16n and a pipe 16q. The G port of the switching valve 8 is connected to the reheat return port 11c via a pipe 16o.

The circulation pump 6a, the hot water storage tank 11, the pipes 16a, 16b, 16h, 16j, 16k, 16n, 16q, and the switching valves 7, 8, 9 direct the heated water flowing out from the water/refrigerant heat exchanger 2 into the hot water storage tank 11. It constitutes a hot water storage circuit 201 that stores hot water.

The circulation pump 6a, the reheating heat exchanger 12, the piping 16b, 16d, 16e, 16f, 16j, 16l, 16o, and the switching valves 7, 8, 9 are configured to allow the reheating heat exchanger 12 to heat the water to be heated on the load side. It constitutes a reheating circuit 202 for heating.

The water to be heated by the reheating heat exchanger 12 is not limited to the above-mentioned bath water, and may be, for example, circulating water for floor heating. The circulation pump 6a does not necessarily need to be installed in the hot water storage unit 200, and may be installed in the heat pump unit 100 side. Further, the high temperature water inlet 11b, medium temperature water outlet 11d, piping 16q, mixing valve 10, and hot water mixing unit 15 constitute a hot water supply circuit 203 that takes out hot water from the hot water storage tank 11 and supplies it to the bathtub or the hot water supply end. There is.

In this embodiment, the value of the heating capacity and the value of the boiling temperature by the refrigerant circuit 101 of the heat pump unit 100 can be changed. In the following description, the heating capacity of the refrigerant circuit 101 of the heat pump unit 100 may be simply referred to as "heating capacity." The heating capacity corresponds to the amount of heat that the heat pump unit 100 gives to water per hour. The unit of heating capacity is, for example, kW (kilowatt). The compressor 1 is driven by a drive device (not shown) including, for example, an inverter-controlled DC brushless motor. In this case, by adjusting the rotation speed of the compressor 1 using the drive device, the pressure and temperature of the refrigerant discharged from the compressor 1 can be changed, and the value of the heating capacity can be changed. However, in the heat pump water heater of the present disclosure, there is no need to use such a drive device. For example, the heat pump unit 100 can be equipped with a plurality of compressors, and the number of compressors that are in operation can be changed. , the pressure and temperature of the refrigerant to be discharged, or the value of the heating capacity may be changed.

Next, the control system of the heat pump water heater will be explained. In the following description, the temperature of the heated water flowing out from the water-refrigerant heat exchanger 2 will be referred to as "boiling temperature." The heat pump unit 100 includes an inlet water temperature sensor 13a that detects the temperature of water flowing into the water-refrigerant heat exchanger 2, a boiling temperature sensor 13b that detects the boiling temperature, and an outside air temperature around the heat pump unit 100. It also includes an outside air temperature sensor 13c. The boiling temperature sensor 13b is arranged near the outlet of the water-refrigerant heat exchanger 2. The refrigerant circuit 101 also includes a discharge temperature sensor 13d that detects the temperature of the refrigerant discharged from the compressor 1, a suction temperature sensor 13e that detects the temperature of the refrigerant sucked into the compressor 1, and an air heat exchanger 4. The evaporation temperature sensor 13f detects the temperature of the refrigerant at the inlet or intermediate position of the refrigerant. The hot water storage unit 200 is provided with a plurality of hot water storage temperature sensors 13g, 13h, 13i, and 13j. The hot water storage temperature sensors 13g, 13h, 13i, and 13j are installed in the hot water storage tank 11 at positions at different heights, and detect the water temperature in the hot water storage tank 11 at each installation location.

The heat pump water heater of this embodiment includes a heat pump control device 14 mounted on a heat pump unit 100 and a water heater control device 50 mounted on a hot water storage unit 200. Each of the heat pump control device 14 and the water heater control device 50 includes a microcomputer having a memory and a processor. The heat pump control device 14 and the water heater control device 50 are connected to be able to communicate in both directions. In this embodiment, the heat pump control device 14 and the water heater control device 50 cooperate to control the operation of the heat pump water heater. The heat pump control device 14 and the water heater control device 50 correspond to control means that controls a boiling operation in which hot water heated by the heat pump unit 100, that is, heated water, flows into the hot water storage tank 11.

In the present disclosure, the heat pump control device 14, the water heater control device 50, and the remote control 51 may cooperate to control the operation of the heat pump water heater. In the following description, any process described as being executed by the water heater control device 50 may be executed by the heat pump control device 14 alone, or may be executed by the water heater control device 50 alone. , the remote controller 51 may execute the operation alone, or two or more of the heat pump control device 14, the water heater control device 50, and the remote control 51 may execute the operation in cooperation. Further, the control means of the heat pump water heater in the present disclosure is not limited to the configuration in which a plurality of control devices cooperate as in the present embodiment, but may be configured by a single control device.

Bidirectional communication is possible between the water heater control device 50 and the remote controller 51 by wired or wireless communication. Remote control 51 is an example of a user interface. The remote control 51 has a display section 51a that displays information and an operation section 51b that is operated by a user. The remote control 51 may include a touch screen that functions as both a display section 51a and an operation section 51b. By operating the remote controller 51, a person such as a user can remotely control the heat pump water heater and make various settings. The display section 51a has a function as a notification means for notifying information to a person such as a user. The remote control 51 in this embodiment includes the display section 51a as a notification means, but as a modification, it may also include other notification means such as a voice guidance device. The remote control 51 may be installed on a wall in the kitchen, living room, bathroom, etc., for example. A plurality of remote controllers 51 may be able to communicate with the water heater control device 50. In addition to or in place of the remote control 51, a device such as a mobile terminal such as a smartphone, a smart speaker, or a television may be configured to be used as a user interface. The water heater control device 50 and the remote control 51 and other user interfaces may be able to communicate via the Internet or a local area network. In the following description, operations using the remote controller 51 may be substituted for operations using a user interface other than the remote controller 51.

The water heater control device 50 receives outputs from various sensors included in the heat pump water heater, information on the user's operation on the remote controller 51, and the like. Water heater control device 50 controls the operations of heat pump unit 100 and hot water storage unit 200, respectively, based on this input information. For example, the water heater control device 50 controls the operating states of the compressor 1, the circulation pump 6a, and the reheating pump 6b, the opening degree of the expansion valve 3, the switching valve 7, the switching valve 8, the switching valve 9, and the mixing valve. The flow path direction or switching position of the valve 10 is controlled. Further, the water heater control device 50 executes a boiling operation, a reheating operation, etc., as described later. The water heater control device 50 controls the boiling temperature and the heating capacity of the refrigerant circuit 101 during the boiling operation.

The water heater control device 50 may be configured to be able to receive weather forecast information distributed over the Internet.

In this embodiment, the night time period may be a time period in which the unit price of electricity is cheaper than other time periods. The night time period may be, for example, a time period from 11:00 PM to 7:00 AM the next morning. The daytime period is a time period other than the nighttime period. The daytime time period is, for example, a time period from 7:00 to 23:00. This daytime time period may be a time period in which the unit price of electricity is higher than the nighttime time period. However, the night time period and the day time period are not limited to the example in this embodiment, and their start time and end time may change depending on the contract with the power supply company, etc. It is. The water heater control device 50 stores information on the start time and end time of the night time period and the daytime time period. The water heater control device 50 has a timer function and a calendar function, and can determine whether the current time is in the night time zone or in the day time zone. Further, the water heater control device 50 may acquire information on the start time and end time of the night time period and the daytime time period from the remote control 51 or an external device.

The water heater control device 50 in this embodiment includes a hot water supply heat amount calculation means 52 that calculates the amount of heat used for hot water supply (hereinafter referred to as "heat amount used for hot water supply"). The hot water supply heat amount calculation unit 52 calculates the water supply temperature detected by the water supply temperature sensor 13k, the hot water temperature detected by the hot water temperature sensor 13l, the hot water temperature detected by the bath hot water temperature sensor 13m, and the hot water flow rate detected by the hot water flow rate sensor 17a. The amount of heat used for hot water supply is calculated based on the hot water supply flow rate detected by the bath hot water supply flow rate sensor 17b. The water supply temperature detected by the water supply temperature sensor 13k is the temperature of low-temperature water supplied from the water source to the water supply end. The hot water temperature detected by the hot water temperature sensor 13l is the temperature of hot water supplied from the hot water mixing section 15 to the hot water supply end other than the bathtub. The hot water temperature detected by the bath hot water temperature sensor 13m is the temperature of hot water supplied from the hot water mixing section 15 to the bathtub. The hot water supply flow rate detected by the hot water supply flow rate sensor 17a is the flow rate of hot water supplied from the hot water supply mixing section 15 to the hot water supply end. The hot water supply flow rate detected by the bath hot water supply flow rate sensor 17b is the flow rate of hot water supplied from the hot water supply mixing section 15 to the bathtub.

The hot water supply machine control device 50 has a function of learning the amount of heat used for hot water supply by storing data regarding the amount of heat used for hot water supply calculated by the hot water supply heat amount calculating means 52 during a predetermined period in the past. In the present disclosure, the past predetermined period may be, for example, the past two weeks. For example, the water heater control device 50 learns the amount of heat used for hot water supply by statistically processing the amount of heat used for hot water supply over a predetermined period in the past. Further, the water heater control device 50 can learn the amount of heat used for hot water supply for each hour of the day. The amount of heat used for hot water supply in the past predetermined period corresponds to the past hot water supply load.

Next, the boiling operation of the heat pump water heater will be described with reference to FIG. 2. FIG. 2 is a diagram showing the flow of water and refrigerant during boiling operation in the heat pump water heater according to the first embodiment. As shown in FIG. 2, in the boiling operation, by operating the refrigerant circuit 101 and the hot water storage circuit 201, the low-temperature water flowing out from the water intake port 11f of the hot water storage tank 11 is heated by the refrigerant circuit 101, and water-refrigerant heat exchange is performed. High-temperature heated water flowing out from the outlet of the vessel 2 is made to flow into the hot water storage tank 11 from the high-temperature water outlet 11b.

The boiling operation will be further explained below. In the refrigerant circuit 101, the temperature of the high-temperature, high-pressure gas refrigerant discharged from the compressor 1 decreases while radiating heat to the water flowing through the water-refrigerant heat exchanger 2. At this time, if the high pressure side refrigerant pressure is below the critical pressure, the refrigerant radiates heat while being liquefied. Further, the high-pressure low-temperature refrigerant flowing out from the water-refrigerant heat exchanger 2 is reduced in pressure to a low-pressure gas-liquid two-phase state by passing through the expansion valve 3. Then, this refrigerant absorbs heat from the outside air while flowing through the air heat exchanger 4, thereby being evaporated and gasified. The low-pressure refrigerant flowing out of the air heat exchanger 4 is sucked into the compressor 1 and circulated, and this circulation forms a refrigeration cycle, that is, a heat pump cycle.

Furthermore, the switching valve 7 connects the pipes 16a and 16b to each other, the switching valve 8 connects the pipes 16b and 16n to each other, and the switching valve 9 connects the pipes 16h and 16j to each other. . Thereby, a hot water storage circuit 201 is formed. Then, when the circulation pump 6a operates, water in the hot water storage tank 11 is introduced into the water-refrigerant heat exchanger 2 from the water intake port 11f through the pipes 16h, 16j, and 16k. Then, this water is heated by the gas refrigerant in the water-refrigerant heat exchanger 2 and flows out of the water-refrigerant heat exchanger 2 as heated water. This heated water passes through the pipes 16a, 16b, 16n, and 16q and flows into the hot water storage tank 11 from the high-temperature water outlet 11b. In this way, when the boiling operation is executed, hot water is stored while maintaining a temperature distribution state in which the upper part of the hot water storage tank 11 is high-temperature water and the lower part is low-temperature water.

Next, the temperature control of the heated water and the heating capacity control of the refrigerant circuit 101 executed by the water heater control device 50 during the boiling operation will be described. First, temperature control is feedback control of the rotation speed of the circulation pump 6a so that the boiling temperature detected by the boiling temperature sensor 13b becomes equal to a predetermined target boiling temperature. This feedback control is performed periodically at regular time intervals, for example. In the boiling operation, hot water storage is executed with the target boiling temperature set to a predetermined target hot water storage temperature. That is, the target boiling temperature is equal to the target hot water storage temperature. For example, the water heater control device 50 sets a target hot water storage temperature, that is, a target boiling temperature, in relation to the capacity of the hot water storage tank 11 so that the target hot water storage amount can be stored in the hot water storage tank 11. The target amount of hot water storage corresponds to the target value of the amount of heat stored in the hot water storage tank 11. The water heater control device 50 may set the target amount of hot water storage based on the operation details of the remote controller 51, for example, or may calculate the target amount of hot water storage based on information obtained by learning the amount of heat used for hot water supply in the past. Further, the water heater control device 50 sets the target hot water storage temperature, that is, the target boiling temperature, so that it falls within a predetermined range (for example, 65 to 90° C.).

In the temperature control described above, only the flow rate of heated water flowing in and out of the water-refrigerant heat exchanger 2 is controlled, so the maximum value of the boiling temperature achieved by the temperature control depends on the heating capacity of the refrigerant circuit 101. Therefore, the refrigerant circuit 101 is required to have sufficient heating capacity to realize the target boiling temperature even if it is set to the maximum value within the set range (90° C. in the above example). Therefore, in the heating capacity control, a target value of the heating capacity (target heating capacity) that satisfies the above requirements is set based on, for example, the amount of hot water stored in the hot water storage tank 11, the outside air temperature, the water supply temperature, etc., and the actual value of the refrigerant circuit 101 is The rotation speed and the like of the compressor 1 are controlled so that the heating capacity of the compressor 1 becomes equal to the target heating capacity. By controlling the heating capacity in this way, the required boiling temperature can be stably ensured no matter how the setting of the target boiling temperature and the external conditions change. For example, the heating capacity control is performed periodically at regular time intervals. Moreover, the rotation speed of the compressor 1 is provided with an upper limit rotation speed and a lower limit rotation speed from the viewpoint of durability.

In this embodiment, the value of the heating capacity during the boiling operation may be settable by the user operating the remote control 51. Further, the value of the heating capacity during the boiling operation may be automatically set by the water heater control device 50.

In this disclosure, the amount of heat generated by the boiling operation is referred to as the "boiling amount." The water heater control device 50 calculates a target boiling amount when starting the boiling operation. The water heater control device 50 ends the boiling operation when the boiling amount reaches the target boiling amount. In the present disclosure, the amount of heat remaining in the hot water storage tank 11 at a predetermined time in a day is referred to as "the amount of heat remaining in the hot water at a predetermined time." In the present embodiment, water heater control device 50 calculates the target boiling amount for the day so that the amount of heat remaining in the hot water at a predetermined time is equal to the target value. The predetermined time may be, for example, 23:00 or 9:00 in the morning. The predetermined time may be a predetermined time or a time that can be set by the user operating the remote control 51. The target value of the heat amount of hot water remaining at a predetermined time is a value that serves as an index for preventing the hot water storage tank 11 from running out of hot water. The target value of the residual hot water heat amount at a predetermined time may be, for example, 100L or 0L. The target value of the amount of heat remaining in the hot water at a predetermined time may be a value that is fixed in advance, or may be a value that can be set by the user operating the remote control 51. It can be said that the larger the target value of the heat amount of hot water remaining at a predetermined time is, the more reliably it is possible to prevent the hot water storage tank 11 from running out of hot water, but the amount of power consumption tends to increase.

The water heater control device 50 can predict the amount of heat used for hot water supply on the day from the start of the boiling operation to a predetermined time, based on the data on the amount of heat used for hot water supply learned over a predetermined period in the past. The predicted value of the amount of heat used for hot water supply is referred to as a "predicted value of the amount of heat used for hot water supply." The water heater control device 50 determines the target boiling amount according to, for example, the predicted value of the amount of heat used for hot water supply, the target value of the amount of heat remaining at a predetermined time, and the amount of hot water stored in the hot water storage tank 11 at the start of the boiling operation. It can be calculated. For example, the water heater control device 50 may subtract the amount of hot water stored in the hot water storage tank 11 at the start of the boiling operation from the sum of the predicted value of the amount of heat used for hot water supply and the target value of the amount of heat remaining at a predetermined time. , the target boiling amount may be calculated.

In this disclosure, the heating capacity of the boiling operation on the same day is referred to as "the heating capacity on the same day." The current boiling operation is the boiling operation that will be carried out on the same day. The water heater control device 50 stores the value of the heating capacity of the daily boiling operation in the past predetermined period. In this disclosure, the learned value of the heating capacity of the daily boiling operation in the past predetermined period is referred to as "past heating capacity." The water heater control device 50 may change the heating capacity during one day's boiling operation. If the heating capacity changes during one day's boiling operation, the water heater control device 50 may treat the temporally averaged heating capacity value as the heating capacity value for that day. The water heater control device 50 can calculate the past heating capacity by statistically processing the values of the heating capacity of daily boiling operations in the past predetermined period. For example, the past heating capacity may be a value obtained by averaging the heating capacity values of daily boiling operations during a predetermined period in the past.

When the heating capacity is small, the boiling operation time is longer than when the heating capacity is large. The longer the boiling operation takes, the greater the amount of heat dissipated from the upper part of the hot water storage tank 11 in which hot water is stored during the boiling operation. Furthermore, the longer the boiling operation takes, the more heat is dissipated from the pipes 16a, 16b, 16n, and 16q through which high-temperature hot water passes during the boiling operation. Therefore, when the heating capacity is small, the amount of heat dissipated during the boiling operation is larger than when the heating capacity is large. Conversely, when the heating capacity is large, the amount of heat dissipated during the boiling operation is smaller than when the heating capacity is small.

In view of the above, the water heater control device 50 according to the present embodiment is configured such that when the current heating capacity is greater than the past heating capacity, the current heating capacity is smaller than the past heating capacity. The target boiling amount for the day is corrected so as to reduce the target boiling amount. When the current heating capacity is larger than the past heating capacity, the amount of heat dissipated during the boiling operation is smaller than when the current heating capacity is smaller than the past heating capacity. Therefore, when the current heating capacity is larger than the past heating capacity, even if the target boiling amount for the current day is reduced, it is possible to prevent the actual heat quantity of the remaining hot water at a predetermined time from being insufficient with respect to the target value.

In other words, when the current heating capacity is smaller than the past heating capacity, the water heater control device 50 in the present embodiment has a higher target boiling amount for the current day than when the current heating capacity is larger than the past heating capacity. Correct the target boiling amount for the day so as to increase the amount. When the current heating capacity is smaller than the past heating capacity, the amount of heat dissipated during the boiling operation is larger than when the current heating capacity is larger than the past heating capacity. In this case, by increasing the target boiling amount for the day, it is possible to suppress the actual amount of heat remaining in the hot water at the predetermined time from being insufficient with respect to the target value.

From the above, according to the present embodiment, it is possible to control the actual amount of residual hot water heat at a predetermined time to be as close to the target value as possible. Therefore, it is more advantageous in both reliably preventing the hot water storage tank 11 from running out of hot water and saving power consumption as much as possible.

FIG. 3 is a flowchart illustrating an example of processing when the water heater control device 50 calculates the target boiling amount for the day. When the calculation of the target boiling amount for the day is started, in step S1 of FIG. The target boiling amount is calculated according to the current amount of hot water stored in the hot water storage tank 11.

Next, in step S2, the water heater control device 50 sets the heating capacity for the boiling operation to be performed from now on, that is, the heating capacity for the current day. In this step S2, the water heater control device 50 may set the value set by the user by operating the remote controller 51 as the heating capacity for the day, or automatically set the heating capacity for the day according to predetermined conditions. You may.

Subsequently, in step S3, the water heater control device 50 determines whether the current heating capacity set in step S2 is greater than the past heating capacity. If the heating capacity on the current day is larger than the heating capacity in the past, the process proceeds to step S4, and the water heater control device 50 subtracts the correction amount from the target boiling amount calculated in step S1. Store it as the target boiling amount. On the other hand, if the current heating capacity is less than or equal to the past heating capacity, the process proceeds to step S5, and the water heater control device 50 calculates the value obtained by adding the correction amount to the target boiling amount calculated in step S1. , is stored as the corrected target boiling amount. After step S4 or step S5, the water heater control device 50 ends the process of calculating the target boiling amount for the day. The water heater control device 50 executes the boiling operation for the day using the corrected target boiling amount in step S4 or step S5. The correction amounts in steps S4 and S5 are positive values. The water heater control device 50 may set the value of this correction amount to increase as the absolute value of the difference between the current heating capacity and the past heating capacity increases.

The water heater control device 50 may adjust the target boiling amount for the day using the following equation.
Target boiling amount Q' after adjustment = Target boiling amount Q before adjustment + Adjustment amount A...(1)

The "target boiling amount Q before adjustment" in equation (1) is calculated based on the predicted value of the amount of heat used for hot water supply, the target value of the amount of remaining hot water at a predetermined time, and the current amount of hot water stored in the hot water storage tank 11. This corresponds to the target boiling amount calculated by the control device 50.

The "adjustment amount A" in equation (1) may include a first correction amount D and a second correction amount E, which will be described below. That is, the water heater control device 50 may calculate the adjustment amount A using the following equation.
Adjustment amount A=D+E…(2)

The water heater control device 50 stores error data every day between the target value of the heat amount of remaining hot water at a predetermined time and the actual heat amount of hot water remaining at a predetermined time at a predetermined time, and learns the error in the past predetermined period. You can. The first correction amount D is a value that the water heater control device 50 has learned from this error. For example, the first correction amount D is a value obtained by statistically processing the error between the target value of the heat amount of remaining hot water at a predetermined time and the actual heat amount of hot water remaining at a predetermined time in a past predetermined period.

The second correction amount E is a value calculated by the water heater control device 50 according to the ratio or difference between the past heating capacity and the current heating capacity. For example, the water heater control device 50 may calculate the second correction amount E according to the following equation using the difference (B−C) between the past heating capacity B and the current heating capacity C.
E=(B-C)×θ…(3)
Note that θ is a predetermined coefficient.

Alternatively, the water heater control device 50 may calculate the second correction amount E using the following equation using the ratio C/B between the past heating capacity B and the current heating capacity C.
E=(1-C/B)×φ…(4)
Note that φ is a predetermined coefficient.

The water heater control device 50 ends the boiling operation when the amount of heat generated by the boiling operation reaches the adjusted target boiling amount Q' calculated by equations (1) to (4). You can. In this embodiment, by correcting the target boiling amount for the day using the first correction amount D that has learned the error between the target value of the heat amount of remaining water at a predetermined time and the actual heat amount of remaining water at a predetermined time, It becomes possible to bring the actual heat amount of hot water remaining at a predetermined time closer to the target value with higher accuracy.

When the current heating capacity C is larger than the past heating capacity B, the second correction amount E calculated by equation (3) or equation (4) becomes a negative value. Adding the negative second correction amount E to the adjustment amount A corresponds to the process of step S4 in FIG. When the current heating capacity C is smaller than the past heating capacity B, the second correction amount E calculated by equation (3) or equation (4) becomes a positive value. Adding the positive second correction amount E to the adjustment amount A corresponds to the process of step S5 in FIG.

The temperature of hot water stored in the hot water storage tank 11 during the boiling operation on that day is referred to as "hot water storage temperature on that day." The hot water storage temperature on that day can be considered to be approximately equal to the boiling temperature of the boiling operation on that day. The water heater control device 50 may increase the value of the second correction amount E as the difference between the stored hot water temperature on that day and the outside air temperature on that day detected by the outside air temperature sensor 13c is larger. For example, the water heater control device 50 may increase the value of the coefficient θ in equation (3) or the coefficient φ in equation (4) as the difference between the hot water storage temperature on that day and the outside temperature on that day is larger. The larger the difference between the hot water storage temperature on that day and the outside temperature on that day, the greater the amount of heat dissipated during the heating operation, and the greater the effect. Therefore, the larger the difference between the hot water storage temperature on the day and the outside temperature on the day, the larger the value of the second correction amount E becomes, thereby more reliably correcting the influence of the amount of heat dissipated during the boiling operation. can. Therefore, it is possible to control the actual amount of residual hot water heat at a predetermined time to be closer to the target value.

In this disclosure, the boiling operation performed during the night time period is referred to as the "night boiling operation." Further, the boiling operation performed during the daytime hours, which is a time zone other than the nighttime hours, is referred to as "daytime boiling operation." The water heater control device 50 may cover the target boiling amount by performing both a nighttime boiling operation and a daytime boiling operation in one day (24 hours). That is, the water heater control device 50 may control the water heater controller 50 so that the sum of the amount of heat generated by the nighttime boiling operation and the amount of heat generated by the daytime boiling operation is equal to the target boiling amount.

In the present disclosure, the ratio of the time of the daytime boiling operation to the total time of the nighttime boiling operation and the daytime boiling operation time in one day is referred to as the "daytime boiling ratio." The water heater control device 50 can calculate the learned value of the daytime boiling ratio for the past predetermined period by storing the daily daytime boiling ratio values for the past predetermined period and statistically processing those values. For example, the learned value of the daytime boiling ratio for the past predetermined period may be a value obtained by averaging the daily daytime boiling ratio values for the past predetermined period.

The amount of heat used for hot water supply tends to be greatest in the evening when bathtubs are filled with hot water and people take a bath. In other words, it can be said that the hot water stored in the hot water storage tank 11 is mainly consumed in the evening hours. Hot water generated during the daytime boiling operation is stored in the hot water storage tank 11 for a short time until it is consumed in the evening. Therefore, the amount of heat dissipated from the hot water generated during the daytime boiling operation and stored in the hot water storage tank 11 is small. On the other hand, hot water generated during nighttime boiling operation is stored in the hot water storage tank 11 for a long time before being consumed in the evening. Therefore, a large amount of heat is dissipated from the hot water generated during the nighttime boiling operation and stored in the hot water storage tank 11. Therefore, the higher the daytime boiling ratio is, the less heat is dissipated from the hot water storage tank 11, and the lower the daytime boiling ratio is, the more heat is dissipated from the hot water tank 11.

The water heater control device 50 can predict the daytime boiling rate for the current day. For example, the water heater control device 50 uses the target boiling amount for the day and the heating capacity for the day to calculate the predicted time for the nighttime boiling operation and the predicted time for the daytime boiling operation. You can predict the daytime boiling rate for the day. If the daytime boiling ratio of the current day is larger than the learned value of the daytime boiling ratio of the past predetermined period, the water heater control device 50 sets the daytime boiling ratio of the current day to the learned value of the daytime boiling ratio of the past predetermined period. The target boiling amount for the day may be smaller than the case where it is smaller than .

For example, the water heater control device 50 may calculate the adjustment amount A using the following equation instead of the above-mentioned equation (2).
Adjustment amount A=D+E+F…(5)

The third correction amount F in Equation (5) is a correction amount according to the ratio or difference between the daytime boiling ratio of the current day and the learned value of the daytime boiling ratio of the past predetermined period. By using the third correction amount F, it is possible to correct the influence of variations in the amount of heat dissipated from the hot water storage tank 11 depending on the difference in the daytime boiling ratio. Therefore, it is possible to bring the actual heat value of the remaining hot water at a predetermined time closer to the target value with higher accuracy.

The water heater control device 50 can store the daily outside air temperature detected by the outside air temperature sensor 13c and calculate the average value of the outside air temperature for a predetermined period in the past. The higher the outside air temperature is, the smaller the amount of heat dissipated from the hot water storage tank 11 becomes, so it can be said that the target boiling amount may be reduced. In view of this, if the outside air temperature on the current day is higher than the average value of the outside air temperature over the past predetermined period, the water heater control device 50 determines that the outside air temperature on the current day is higher than the average outside air temperature over the past predetermined period. The target boiling amount for the day may be smaller than when the temperature is low.

For example, the water heater control device 50 may calculate the adjustment amount A using the following equation instead of the above-mentioned equation (2).
Adjustment amount A=D+E+F+G…(6)

The fourth correction amount G in Equation (6) is a correction amount that corresponds to the ratio or difference between the outside air temperature on that day and the average value of outside air temperatures over a predetermined period in the past. By using the fourth correction amount G, it is possible to correct the influence of the amount of heat dissipated from the hot water storage tank 11 varying depending on the outside temperature on that day. Therefore, it is possible to bring the actual heat value of the remaining hot water at a predetermined time closer to the target value with higher accuracy. Note that the water heater control device 50 may use the value detected by the outside air temperature sensor 13c as the value of the outside air temperature on that day, or may predict the outside air temperature on that day from weather forecast information.

Embodiment 2.
Next, a second embodiment will be described with reference to FIG. 4, focusing on differences from the first embodiment described above, and common explanations will be simplified or omitted. Further, elements common to or corresponding to those described above are given the same reference numerals.

FIG. 4 is a schematic cross-sectional view of a building 300 in which a heat pump water heater according to the second embodiment is installed. As shown in FIG. 4, a building 300 is equipped with a heat pump unit 100, a hot water storage unit 200, a solar power generation device 60, a distribution panel 61, a power distribution control device 62, and the like. The purpose of the building 300 may be, for example, a residence, a store, a facility, an office, or the like.

The solar power generation device 60 includes solar cells and the like that generate electricity by receiving sunlight, and performs solar power generation. The solar power generation device 60 is connected to the input side of the distribution board 61 via wiring 64 and transmits the generated power to the distribution board 61. The distribution board 61 is configured as a power supply circuit that performs input/output and distribution of electric power, and is connected to the electric power system of the electric power company via a power line 63. The distribution board 61 buys power from the power company via the power line 63 and sells power to the power company via the power line 63. A hot water storage unit 200 is connected to the output side of the distribution board 61 via wiring 65. The heat pump water heater operates in response to electric power supplied from the distribution board 61 through wiring 65. In the following description, electrical equipment (not shown) that receives power from the distribution board 61 other than the heat pump water heater will be referred to as "other electrical equipment". Other electrical equipment may include, for example, at least one of an air conditioner, a lighting fixture, a refrigerator, a washing machine, and an electric vehicle. Other electrical devices are connected to the output side of the distribution board 61 via wiring (not shown).

The power distribution control device 62 is connected to the distribution board 61 via wiring 66. Power distribution control device 62 includes at least one memory and at least one processor. The power distribution control device 62 may be configured by, for example, an EMS (Energy Management System) controller or the like. The power distribution control device 62 has a function of acquiring information on the solar power generation device 60 and information on the heat pump water heater via the distribution board 61 or the communication device 70, a function of controlling the operating state of the distribution board 61, and a function of controlling the operation state of the distribution board 61. It also has a function of transmitting commands to the water heater control device 50 via the device 70.

The information acquired by the power distribution control device 62 includes information on the amount of power generated by the solar power generation device 60 and information on the amount of hot water stored in the hot water storage tank 11. The power distribution control device 62 is provided with a selection switch 62a used for various operations. The power distribution control device 62 has a function of communicating with an external network such as the Internet via the communication device 70 and acquiring various information such as weather forecast information from the external network. The communication device 70 may be configured to perform wireless communication with the water heater control device 50 and the power distribution control device 62.

In the following description, the sum of the power consumption of the heat pump water heater and the power consumption of other electrical devices will be referred to as "total power consumption." The water heater control device 50 has a plurality of operation modes with different heating capacity values for boiling operation. The smaller the heating capacity, the lower the power consumption of the heat pump water heater during boiling operation.

Next, the operation of the solar power generation device 60 according to this embodiment will be explained. The solar power generation device 60 receives daytime sunlight and generates power. Electric power generated by sunlight is transmitted to the distribution board 61 via wiring 64. At this time, the distribution board 61 reversely flows the power obtained by subtracting the total power consumption from the power generated by the solar power generation device 60 through the power line 63, and sells the power to the power company.

When the solar power generation device 60 is not generating power, the distribution board 61 supplies power supplied from the power company via the power line 63 to the heat pump water heater. Note that the operation of the electricity distribution board 61 may be executed based on a command from a control circuit or the like mounted on the electricity distribution board 61, or may be performed based on a command from the power distribution control device 62.

The heat pump water heater of this embodiment can perform a PV boiling operation, which is a boiling operation using surplus electric power of the electric power generated by the solar power generation device 60. PV boiling operation corresponds to daytime boiling operation.

The power distribution control device 62 includes a surplus power calculation section. The surplus power calculation unit calculates the surplus power generated by solar power generation from the power generation amount of the solar power generation device 60 and the power consumption of electric devices other than the heat pump water heater. The surplus power calculation unit can calculate the surplus power by subtracting the power consumption of electric devices other than the heat pump water heater from the power generation amount of the solar power generation device 60. The power distribution control device 62 learns information on daily surplus power during a predetermined past period (for example, the past two weeks). The power distribution control device 62 may learn surplus power information as well as time information.

The power distribution control device 62 includes a surplus power prediction unit that predicts the value of surplus power to be generated on the next day. For example, the surplus power prediction unit may predict the value of surplus power at each time that will occur on the next day using information on surplus power learned over a predetermined period in the past and weather forecast information for the next day. The value of surplus power predicted by the surplus power prediction unit is hereinafter referred to as "surplus power predicted value." The water heater control device 50 sets the time for the PV boiling operation to be performed on the next day according to the predicted surplus power value.

During the PV heating operation, the water heater control device 50 receives information about the current actual surplus power value calculated by the surplus power calculation unit from the power distribution control device 62. If the weather during the PV heating operation becomes worse than the weather forecast, the actual surplus power will be smaller than the predicted surplus power value. In this case, the time during which the PV boiling operation can be performed may be shorter than the set value set on the previous day.

Therefore, while performing the PV boiling operation, the water heater control device 50 predicts whether the time during which the PV boiling operation can be performed will reach the set value. For example, the water heater control device 50 compares the actual surplus power with the predicted surplus power value at each time to predict whether the time during which the PV boiling operation can be performed will reach the set value.

Here, it is assumed that the current heating capacity of the PV boiling operation is smaller than the past heating capacity, and the target boiling amount for the day has been corrected to increase. That is, assume the case where the second correction amount E>0 described in the first embodiment. In this case, if the water heater control device 50 predicts that the time during which the PV boiling operation can be performed will be less than the set value, the water heater control device 50 will adjust the actual boiling amount to the target boiling amount before performing the increase correction. When it reaches that point, the PV boiling operation ends. That is, the water heater control device 50 considers that the second correction amount E=0, and ends the PV boiling operation.

Thus, in this embodiment, the second correction amount E>0, the actual surplus power is less than predicted, and the time during which PV boiling operation can be performed is predicted to be less than the set value. In this case, the water heater control device 50 assumes that the second correction amount E=0, and when the actual boiling amount reaches the target boiling amount to which the second correction amount E is not added, the PV End boiling operation. Thereby, the PV heating operation can be ended early, so even if the actual surplus power is less than predicted, an increase in the amount of power purchased from the electric power company can be suppressed. In this case, the actual predetermined time remaining hot water heat amount is expected to be smaller than the target value by the original second correction amount E. However, the error between the target value of the heat amount of the remaining hot water at the predetermined time and the actual heat amount of the remaining hot water at the predetermined time in the past predetermined period is corrected by the first correction amount D. Therefore, it can be considered that the shortfall in the actual heat amount of the remaining hot water at the predetermined time from the target value is small. Therefore, there is a small possibility that the hot water storage tank 11 will run out of hot water, and therefore, there is a small possibility that the user's usability will be affected.

Note that among the features of the plurality of embodiments described above, two or more features that can be combined may be combined and implemented.

Hereinafter, various aspects of the present disclosure will be collectively described as supplementary notes.

(Additional note 1)
A heating means that has a heat pump cycle that heats water and whose heating capacity can be changed;
hot water storage tank,
A control means for controlling a boiling operation in which hot water heated by the heating means flows into the hot water storage tank;
A heat pump water heater comprising:
The control means ends the boiling operation when the boiling amount, which is the amount of heat generated by the boiling operation, reaches a target boiling amount,
When the current heating capacity, which is the heating capacity of the boiling operation on the current day, is larger than the past heating capacity, which is the learned value of the heating capacity of the boiling operation in the past predetermined period, the control means A heat pump water heater that reduces the target boiling amount on the day compared to a case where the heating capacity on that day is smaller than the heating capacity in the past.
(Additional note 2)
The heat pump hot water supply according to appendix 1, wherein the control means calculates the target boiling amount for the day so that the amount of heat remaining in the hot water at a predetermined time, which is the amount of heat remaining in the hot water storage tank at a predetermined time, is equal to the target value. Machine.
(Additional note 3)
The control means includes a first correction amount that is a value learned in a past predetermined period of the difference between the target value of the heat amount of the remaining hot water at the predetermined time and the actual heat amount of the remaining hot water at the predetermined time, the past heating capacity, and the current day. A second correction amount according to the ratio or difference with the heating capacity is calculated, and the target boiling amount for the day is corrected using the first correction amount and the second correction amount. heat pump water heater.
(Additional note 4)
The control means corrects the target boiling amount for the current day using a correction amount according to a ratio or difference between the past heating capacity and the current heating capacity,
Supplementary Notes 1 to 3, wherein the control means increases the value of the correction amount as the difference between the hot water storage temperature, which is the temperature of hot water stored in the hot water storage tank during the boiling operation on the day, and the outside air temperature on the day is large. The heat pump water heater according to any one of the above.
(Appendix 5)
The control means performs a night boiling operation, which is the boiling operation performed during the night time, and a daytime boiling operation, which is the boiling operation performed during a time other than the night time. It is possible and
The ratio of the daytime boiling operation time to the total time of the nighttime boiling operation and the daytime boiling operation time in one day is the daytime boiling ratio,
When the daytime boiling ratio on the current day is larger than the learned value of the daytime boiling ratio in the past predetermined period, the control means controls the daytime boiling ratio on the current day to be the same as the daytime boiling ratio in the past predetermined period. The heat pump water heater according to any one of Supplementary Notes 1 to 4, which reduces the target boiling amount for the day compared to a case where it is smaller than a learned value.
(Appendix 6)
When the outside air temperature on the current day is higher than the average value of the outside air temperature over a predetermined period in the past, the control means controls the temperature on the current day. The heat pump water heater according to any one of Supplementary notes 1 to 5, which reduces the target boiling amount.
(Appendix 7)
The heat pump water heater is capable of carrying out a PV boiling operation, which is the boiling operation, using surplus electricity of the electricity generated by the solar power generation device,
In a case where the current heating capacity is smaller than the past heating capacity and the target boiling amount for the day has been corrected to increase, during the execution of the PV boiling operation, the control means controls the PV boiling operation. Supplementary Note 1: When the actual boiling amount is predicted to be less than the set value, the PV boiling operation is terminated when the actual boiling amount reaches the target boiling amount before the increase correction is performed. The heat pump water heater according to any one of appendix 6.

1 compressor, 2 water refrigerant heat exchanger, 3 expansion valve, 4 air heat exchanger, 5 fan, 6a circulation pump, 6b reheating pump, 7, 8, 9 switching valve, 10 mixing valve, 11 hot water storage tank, 11a High temperature water intake port, 11b High temperature water inlet, 11c Reheating return port, 11d Medium temperature water outlet, 11e Low temperature water return port, 11f Water intake port, 11g Water supply port, 12 Reheating heat exchanger, 13a Inlet water temperature sensor, 13b Boiling temperature sensor, 13c Outside air temperature sensor, 13d Discharge temperature sensor, 13e Suction temperature sensor, 13f Evaporation temperature sensor, 13g, 13h, 13i, 13j Hot water storage temperature sensor, 13k Water supply temperature sensor, 13l Hot water supply temperature sensor, 13m Bath water supply temperature sensor, 14 heat pump control device, 15 hot water mixing unit, 17a hot water supply flow rate sensor, 17b bath hot water supply flow rate sensor, 50 water heater control device, 51 remote control, 51a display section, 51b operation section, 52 hot water supply heat amount calculation means, 60 solar power generation device, 61 distribution board, 62 power distribution control device, 62a selection switch, 62b display section, 63 power line, 64 wiring, 65 wiring, 66 wiring, 70 communication device, 100 heat pump unit, 101 refrigerant circuit, 200 hot water storage unit, 201 hot water storage Circuit, 202 Reheating circuit, 203 Hot water supply circuit, 300 Building

Claims (7)

A heating means that has a heat pump cycle that heats water and whose heating capacity can be changed;
hot water storage tank,
A control means for controlling a boiling operation in which hot water heated by the heating means flows into the hot water storage tank;
A heat pump water heater comprising:
The control means ends the boiling operation when the boiling amount, which is the amount of heat generated by the boiling operation, reaches a target boiling amount,
When the current heating capacity, which is the heating capacity of the boiling operation on the current day, is larger than the past heating capacity, which is the learned value of the heating capacity of the boiling operation in the past predetermined period, the control means A heat pump water heater that reduces the target boiling amount on the day compared to a case where the heating capacity on that day is smaller than the heating capacity in the past. The heat pump according to claim 1, wherein the control means calculates the target boiling amount for the day so that the amount of heat remaining in the hot water at a predetermined time, which is the amount of heat remaining in the hot water storage tank at a predetermined time, is equal to a target value. Water heater. The control means includes a first correction amount that is a value learned in a past predetermined period of the difference between the target value of the heat amount of the remaining hot water at the predetermined time and the actual heat amount of the remaining hot water at the predetermined time, the past heating capacity, and the current day. 3. A second correction amount according to a ratio or difference with heating capacity is calculated, and the target boiling amount for the day is corrected using the first correction amount and the second correction amount. The heat pump water heater described. The control means corrects the target boiling amount for the current day using a correction amount according to a ratio or difference between the past heating capacity and the current heating capacity,
The control means increases the value of the correction amount as the difference between the hot water storage temperature, which is the temperature of the hot water stored in the hot water storage tank during the boiling operation on the day, and the outside air temperature on the day is large. The heat pump water heater according to any one of Item 3. The control means performs a night boiling operation, which is the boiling operation performed during the night time, and a daytime boiling operation, which is the boiling operation performed during a time other than the night time. It is possible and
The ratio of the daytime boiling operation time to the total time of the nighttime boiling operation and the daytime boiling operation time in one day is the daytime boiling ratio,
When the daytime boiling ratio on the current day is larger than the learned value of the daytime boiling ratio in the past predetermined period, the control means controls the daytime boiling ratio on the current day to be the same as the daytime boiling ratio in the past predetermined period. The heat pump water heater according to any one of claims 1 to 3, wherein the target boiling amount for the day is smaller than when it is smaller than a learned value. When the outside air temperature on the current day is higher than the average value of the outside air temperature over a predetermined period in the past, the control means controls the temperature on the current day. The heat pump water heater according to any one of claims 1 to 3, wherein the target boiling amount is reduced. The heat pump water heater is capable of carrying out a PV boiling operation, which is the boiling operation, using surplus electricity of the electricity generated by the solar power generation device,
In a case where the current heating capacity is smaller than the past heating capacity and the target boiling amount for the day has been corrected to increase, during the execution of the PV boiling operation, the control means controls the PV boiling operation. If the actual boiling amount is predicted to be less than the set value, the PV boiling operation is ended when the actual boiling amount reaches the target boiling amount before the increase correction is applied. The heat pump water heater according to any one of claims 1 to 3.

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