JP3876738B2 - Heat pump type water heater and its boiling control method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to control of a boiling operation of a heat pump type water heater.
[0002]
[Prior art]
Recently, heat pump type water heaters using CO ₂ refrigerant are known. This water heater has the advantage that the boiling temperature can be heated to a high temperature of 90 ° C. or higher and the heating efficiency is high, but the liquid supplied to the heat pump main body that heats the hot water supply liquid using the heat pump cycle As the temperature increases, the heating efficiency decreases.
[0003]
In addition, when the amount of hot water used is small, a large amount of hot water remains in the hot water storage tank, and the large amount of hot water in the hot water storage tank drops uniformly, and when the heating operation starts, a small amount of water is boiled and immediately supplied to the heat pump. The liquid temperature exceeds the overheat stop temperature and the operation is immediately stopped.
[0004]
6 is a block diagram of a conventional heat pump type water heater, FIG. 7 is a block diagram of a conventional heat pump body, FIG. 8 is a block diagram of a conventional control device, and 9 is a conventional boiling control operation. It is a flowchart.
In FIG. 6, 1 is a hot water supply body, 2 is a hot water storage tank disposed in the main body 1, 3 is a water supply pipe connected to the lower part of the hot water storage tank 2, and 3 a is a pressure reduction provided in the water supply pipe 3. A valve 4 is a hot water supply pipe connected to the upper part of the hot water storage tank 2, 4 a is a relief valve, and 5 a is a temperature sensor A that is attached to the outer wall surface of the hot water storage tank 2 and detects the temperature of water in the hot water storage tank 2. By attaching the temperature sensor A5a to a position of a predetermined capacity on the outer wall surface of the hot water storage tank 2, the amount of hot water in the hot water storage tank 2 is also detected from the detected temperature at the attachment position. Reference numeral 6 denotes a temperature sensor C that is attached to the lower pipe of the hot water storage tank 2 and detects the temperature for stopping the heating operation of the heat pump main body 12 when the entire hot water storage tank 2 is boiled.
[0005]
7 is a circulation in which the water in the hot water storage tank 2 is circulated between the heat pump main body 10 by the cold water pipe 10a and the hot water pipe 10b in order to replace the heat generated in the heat cycle of the heat pump main body 10 with the water in the hot water storage tank 2. It is a pump. Water is supplied to the heat pump main body 10 by the circulation pump 7 from the cold water pipe 10a connected to the lower part of the hot water storage tank 2, and the water heated by the heat pump main body 10 is returned by the hot water pipe 10b connected to the upper part of the hot water storage tank 2. 2 Store hot water from the upper part.
[0006]
In FIG. 8, 8 is a control unit for controlling the boiling of the water in the hot water storage tank 2 and the start / stop of the operation of the heat pump body 10, and the detected values and the boiling temperature of the temperature sensor A5a and the temperature sensor C6. On the basis of the input value from the operation unit 9 for setting the heating operation start / stop of the heat pump body 10 and the operation of the circulation pump 7 are controlled.
[0007]
In FIG. 7, the heat pump cycle of the heat pump body 10 is configured by connecting a compressor 11, a hot water supply heat exchanger 12, an expansion valve 13, an outdoor heat exchanger 14, and an accumulator 15 through a refrigerant pipe 10 c in order. Here, a fan 16 is attached to the outdoor heat exchanger 14 to absorb heat, and the hot water supply heat exchanger 12 exchanges heat between the high-pressure gas refrigerant discharged from the compressor 11 and hot water supply water. It has a refrigerant passage 12a through which refrigerant flows and a hot water supply water passage 12b through which hot water is supplied.
[0008]
Next, a conventional boiling control operation will be described with reference to the flowchart of FIG.
First, when boiling control is started (S1), the temperature of the hot water tank 2 wall surface is detected by the temperature sensor A5a to determine whether or not the predetermined remaining hot water amount for starting the heating operation is reached by the control unit 8 (S13). When the temperature sensor A5a becomes a predetermined temperature (for example, 45 ° C.) or less, it is determined that the predetermined remaining hot water amount (75 L) or less is reached (S14), and the heat pump main body is operated by operating the circulation pump 7 and the heat pump cycle according to the instruction of the control unit 8 10 starts a heating operation with a constant heating capacity (for example, 4.5 kW) (S4), boils hot water at the hot water storage temperature T ₁ ° C (for example, 90 ° C.) set by the operation unit 9 from the upper part of the hot water storage tank 2, temperature sensor A5a it is determined whether the detected hot water storage temperature _{T 1} ° C. (for example 90 ℃) (S9), the temperature sensor A5a detects _{T 1} ° C. (e.g., 90 ° C.), to stop the heating operation (S11) . When the temperature sensor A5a does not detect the hot water storage temperature T ₁ ° C. (for example, 90 ° C.), it is determined whether the temperature sensor C6 has detected a predetermined temperature T ₂ ° C. (for example, 60 ° C.) (S10). predetermined temperature _{T 2} ° C. (for example 60 ° C.) to return to the judgment temperature sensor A5a when not in detection of whether the detected hot water storage temperature _{T 1} ° C. (for example 90 ° C.) to (S9), the temperature sensor C6 predetermined temperature _{T 2} When the temperature (for example, 60 ° C.) is detected, the heating operation of the heat pump main body 10 is stopped by an instruction from the control unit 8 (S11), and the boiling control is finished (S12).
[0009]
[Problems to be solved by the invention]
When the amount of hot water used on the previous day is small, the amount of remaining hot water increases and a large amount of hot water in the hot water storage tank 2 decreases uniformly. When the next heating operation starts, The temperature of the liquid supplied to the heat pump becomes equal to or higher than the heating stop temperature, the operation is immediately stopped, the amount of stored heat decreases, and there is a problem that hot water runs out when hot water is used as usual on the day.
[0010]
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a heat pump type water heater that can prevent hot water from running out the next day even if the amount used is smaller than normal. .
[0011]
[Means for Solving the Problems]
The heat pump type hot water heater according to claim 1 of the present invention heats a hot water supply liquid using a heat pump cycle, stores the heated liquid from the upper part of the hot water storage tank of the hot water supply body, and supplies the heating source from the lower part of the hot water storage tank. pump body back is, the temperature of the liquid back to the heat Toponpu body becomes a predetermined temperature set in advance lower than the hot-water storage temperature, to stop the heating operation of the heat pump body, while the remaining hot water in the hot water storage tank is below a predetermined amount Then, in the heat pump type water heater that starts the heating operation of the heat pump body, the hot water storage means for storing the past hot water usage, and the hot water usage the previous day from the past hot water storage stored in the hot water storage means is a predetermined amount. When the amount is less than the above, there is provided a heating operation start remaining hot water amount changing means for changing the remaining hot water amount at the start of the heating operation more.
[0012]
The heat pump type hot water heater according to claim 2 heats the hot water supply liquid using a heat pump cycle, stores the heated liquid from the upper part of the hot water storage tank of the hot water supply body, and is a heating source from the lower part of the hot water storage tank. back to the heat pump body, the temperature of the liquid back to the heat Toponpu body becomes a predetermined temperature set in advance lower than the hot-water storage temperature, to stop the heating operation of the heat pump body, whereas, when the amount of hot water storage tank falls below a predetermined amount, In a heat pump type water heater for starting the heating operation of the heat pump main body, used hot water amount storage means for storing a past used hot water amount, heating start remaining hot water amount storage means for storing a past heating operation starting remaining hot water amount, and said used hot water amount storage means When the amount of hot water used on the previous day is less than the predetermined amount of hot water stored in the past, the remaining hot water amount at the start of the heating operation is determined only once. Ku change, heating operation starting amount of hot water later has a heating operation start remaining hot water changing means for the past remaining hot water stored in the heating start remaining hot water storage unit.
[0013]
According to a third aspect of the present invention, there is provided a method for controlling the boiling of a heat pump type water heater, wherein a liquid for hot water supply is heated using a heat pump cycle, the heated liquid is stored from an upper part of a hot water storage tank of a hot water heater body, back to the heat pump body is more heat source, the temperature of the liquid back to the heat Toponpu body becomes a predetermined temperature set in advance lower than the hot-water storage temperature, to stop the heating operation of the heat pump body, whereas, the remaining hot water is Tokoro of the hot water storage tank When heating up the heat pump water heater that starts heating operation of the heat pump body below the fixed amount, the past hot water volume is stored, and the heating operation is performed when the hot water volume of the previous day is less than the past hot water volume by a predetermined amount or more. Change the amount of remaining hot water at the start.
[0014]
According to a fourth aspect of the present invention, there is provided a method for controlling the boiling of a heat pump type hot water heater, wherein a liquid for hot water supply is heated using a heat pump cycle, the heated liquid is stored from an upper part of a hot water storage tank of a hot water heater body, back to the heat pump body is more heat source, the temperature of the liquid back to the heat Toponpu body becomes a predetermined temperature set in advance lower than the hot-water storage temperature, to stop the heating operation of the heat pump body, whereas, the remaining hot water is Tokoro of the hot water storage tank When the heating pump body heating operation starts when the heat pump becomes less than the fixed amount, the past hot water usage and the past heating operation remaining hot water amount are stored in the heating control of the heat pump water heater. When the amount is more than the fixed amount, the amount of remaining hot water at the start of the heating operation is changed only once, and the remaining amount of hot water at the start of the subsequent heating operation is stored in the past. To hot water.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
FIG. 1 is a block diagram of a heat pump type water heater showing Embodiment 1 of the present invention, FIG. 2 is a block diagram of a control device in Embodiment 1 of the present invention, and FIG. 3 is boiling in Embodiment 1 of the present invention. It is a flowchart which shows control operation.
In addition, since the block diagram of the heat pump main body 10 in Embodiment 1 of this invention is the same as the conventional structure shown in FIG. 7, description is abbreviate | omitted.
[0016]
The difference between the configuration diagram of the first embodiment of the present invention shown in FIG. 1 and the configuration diagram of the conventional heat pump type water heater shown in FIG. 6 is that the first embodiment of the present invention is used for four hot water supply pipes. The addition of the flow sensor 17 for detecting the amount of hot water, the configuration of the control unit 8, and the temperature sensor B5b are attached.
That is, in the first embodiment of the present invention, the control unit 8 controls the boiling of water in the hot water storage tank 2 and the start / stop of the operation of the heat pump main body 10, as well as the heating operation start remaining hot water amount changing means 8 a. The temperature sensor B5b is attached to the lower part of the hot water storage tank 2 as compared with the temperature sensor A5a, and can detect a larger amount of remaining hot water than the temperature sensor A5a.
[0017]
The heating control operation of the heat pump type water heater in the first embodiment will be described with reference to the flowchart of FIG.
In addition, description is abbreviate | omitted about the same part as a prior art example, or an equivalent part.
[0018]
First, when boiling control is started (S1), the controller 8 detects the amount of hot water used by the flow sensor 17, and reads the past hot water amount stored in the hot water storage unit 8b (S2). Also, the amount of hot water used on the previous day is read (S3). Compare the amount of hot water used on the previous day with the amount of hot water used in the past (S4). If the amount of hot water used on the previous day is more than a predetermined amount (for example, 100L) compared to the amount of hot water used in the past, 2 determines that the amount of stored heat is small, and detects the amount of remaining hot water at the start of the heating operation by the temperature sensor B5b having a larger amount of remaining hot water than the temperature sensor A5a (S6). When the temperature sensor B5b detects a predetermined temperature (for example, 45 ° C.) or less, it is determined that the amount of remaining hot water (150L) or less is reached (S7), and the circulation pump 7 and the heat pump main body 10 have a certain heating capacity according to the instruction of the control unit 8. The heating operation is started at (for example, 4.5 KW) (S8), the hot water is boiled from the upper part of the hot water storage tank 2 at the hot water storage temperature T ₁ ° C. (for example, 90 ° C.) set by the operation unit 9, and the temperature sensor B5b It is determined whether or not T ₁ ° C. (for example, 90 ° C.) has been detected (S9), and when the temperature sensor B5b detects T ₁ ° C. (for example, 90 ° C.), the heating operation is stopped (S11). When the temperature sensor B5b does not detect the hot water storage temperature T ₁ ° C. (for example, 90 ° C.), it is determined whether the temperature sensor C6 has detected a predetermined temperature T ₂ ° C. (for example, 60 ° C.) (S10). When the predetermined temperature T ₂ ° C (for example, 60 ° C) is not detected, the process returns to the determination (S9) as to whether the temperature sensor B5b has detected the hot water storage temperature T ₁ ° C (for example, 90 ° C), and the temperature sensor C6 returns to the predetermined temperature T _2. When the temperature (for example, 60 ° C.) is detected, the heating operation of the heat pump main body 10 is stopped by an instruction from the control unit 8 (S11), and the boiling control is finished (S12).
[0019]
On the other hand, the amount of hot water used on the previous day is compared with the amount of hot water used in the past (S4), and if the amount of hot water used on the previous day is less than a predetermined amount (for example, 100 L) compared to the amount of hot water used in the past (S5), It is determined that the amount of stored heat is large, and the remaining hot water amount at the start of the heating operation is detected by the temperature sensor A5a (S13). When the temperature sensor A5a detects a predetermined temperature (for example, 45 ° C.) or less, it is determined that the predetermined remaining hot water amount (75 L) or less is reached (S14), and the circulation pump 7 and the heat pump main body 10 are heated to a certain degree according to an instruction from the control unit 8. A heating operation is started with a capacity (for example, 4.5 kW) (S8), a predetermined boiling operation is performed, and the boiling control is terminated (S12).
[0020]
As described above, according to the first embodiment, the amount of hot water used on the previous day is more than a predetermined amount (for example, 100 L) compared to the amount of hot water used in the past. Therefore, even when the amount of heat stored in the hot water storage tank is small, boiling can be started from a state where the amount of remaining hot water is large, and hot water shortage can be prevented.
[0021]
Embodiment 2. FIG.
FIG. 4 is a block diagram of the control device according to the second embodiment of the present invention, and FIG. 5 is a flowchart showing the boiling control operation according to the second embodiment of the present invention.
In addition, since the block diagram of the heat pump main body 10 in Embodiment 2 of this invention is the same as the conventional structure shown in FIG. 7, description is abbreviate | omitted.
[0022]
The difference between the configuration diagram of the second embodiment of the present invention shown in FIG. 1 and the configuration diagram of the conventional heat pump type hot water heater shown in FIG. 6 is that the amount of hot water used in the hot water supply piping 4 in the second embodiment of the present invention. The flow sensor 17 for detecting the temperature sensor is provided, the configuration of the controller 8, and the hot water storage tank 2 are provided with a temperature sensor B5b in addition to the temperature sensor A5a.
That is, in the second embodiment of the present invention, the control unit 8 in FIG. 4 controls the boiling of water in the hot water storage tank 2 and the start / stop of the operation of the heat pump body 10, as well as the heating operation start remaining hot water amount. A change means 8a, a hot water storage unit 8b, and a heating operation start remaining hot water storage unit 8c are provided, and the temperature sensor B5b is attached to the lower part of the hot water storage tank 2 as compared with the temperature sensor A5a, and the remaining amount is higher than the temperature sensor A5a. The amount of hot water can be detected.
[0023]
The boiling-up control operation of the heat pump type water heater in Embodiment 2 will be described using the flowchart of FIG.
In addition, description is abbreviate | omitted about the same part as a prior art example, or an equivalent part.
[0024]
First, when boiling control is started (S1), the controller 8 detects the amount of hot water used by the flow sensor 17, and reads the past hot water amount stored in the hot water storage unit 8b (S2). Also, the amount of hot water used on the previous day is read (S3). Compare the amount of hot water used on the previous day with the amount of hot water used in the past (S4). If the amount of hot water used on the previous day is more than a predetermined amount (for example, 100L) compared to the amount of hot water used in the past, 2 determines that the amount of stored heat is small, and detects the amount of remaining hot water at the start of the heating operation by the temperature sensor B5b having a larger amount of remaining hot water than the temperature sensor A5a (S6). When the temperature sensor B5b detects a predetermined temperature (for example, 45 ° C.) or less, it is determined that the predetermined remaining hot water amount (150 L) has been reached (S7), and the circulation pump 7 and the heat pump main body 10 are heated to a certain degree according to instructions from the control unit 8. The heating operation is started with the capacity (for example, 4.5 KW) (S8), the hot water is boiled from the upper part of the hot water storage tank 2 at the hot water storage temperature T ₁ ° C. (for example, 90 ° C.) set by the operation unit 9, and the temperature sensor B5b stores the hot water. It is determined whether or not the temperature T ₁ ° C. (for example, 90 ° C.) has been detected (S9), and when the temperature sensor B5b detects T ₁ ° C. (for example, 90 ° C.), the heating operation is stopped (S11). When the temperature sensor B5b does not detect the hot water storage temperature T ₁ ° C. (for example, 90 ° C.), it is determined whether the temperature sensor C6 has detected a predetermined temperature T ₂ ° C. (for example, 60 ° C.) (S10). When the predetermined temperature T ₂ ° C. (for example, 60 ° C.) is not detected, the process returns to the determination (S9) as to whether the temperature sensor B5b has detected the hot water storage temperature T ₁ ° C. (for example, 90 ° C.). _{When 2} ° C. (for example, 60 ° C.) is detected, the heating operation of the heat pump body 10 is stopped by an instruction from the control unit 8 (S11), and the next heating operation is started in the past stored in the heating operation start remaining hot water storage means 8c. The heating operation start remaining hot water amount is changed (S15), and the boiling control is finished (S12).
[0025]
On the other hand, the amount of hot water used on the previous day is compared with the amount of hot water used in the past (S4), and if the amount of hot water used on the previous day is less than a predetermined amount (for example, 100 L) compared to the amount of hot water used in the past (S5), It is determined that the amount of stored heat is large, and the remaining hot water amount at the start of boiling is detected by the temperature sensor A5a (S13). When the temperature sensor A5a detects a predetermined temperature (for example, 45 ° C.) or less, it is determined that the predetermined remaining hot water amount (75 L) or less is reached (S14), and the circulation pump 7 and the heat pump main body 10 are heated to a certain degree according to an instruction from the control unit 8. A heating operation is started with a capacity (for example, 4.5 KW) (S8), a predetermined boiling operation is performed, and the next heating operation is started after the previous heating operation start remaining stored in the heating operation start remaining hot water storage means 8c. The amount of hot water is changed (S15), and the boiling control is finished (S12).
[0026]
Therefore, according to the second embodiment, the amount of hot water used on the previous day is more than a predetermined amount (for example, 100 L) compared to the amount of hot water used in the past. On the other hand, the remaining amount of hot water at the start of the next heating operation is 75L, so if the amount of heat stored in the hot water storage tank is small, the heating operation is temporarily started from a state where the remaining hot water amount is large and the hot water runs out. Since the amount of remaining hot water at the start of the next heating operation returns to normal, energy saving operation can be performed and the electricity bill can be reduced.
[0027]
【The invention's effect】
As described above, according to the heat pump type water heater of the first aspect of the present invention, the amount of hot water used on the previous day is more than a predetermined amount compared to the amount of hot water used in the past, and if the amount of hot water used is small, Since the amount of hot water is changed a lot, even when the amount of heat stored in the hot water storage tank is small, the heating operation can be started from the state where the amount of remaining hot water is large, and a heat pump water heater that can prevent hot water from running out can be obtained.
[0028]
According to the heat pump water heater of claim 2 according to the present invention, the amount of hot water used on the previous day is more than a predetermined amount compared to the amount of hot water used in the past, and if the amount of hot water is small, the amount of remaining hot water at the start of the heating operation is increased. On the other hand, the amount of remaining hot water at the start of the next heating operation is the normal amount of remaining hot water, so if the amount of heat stored in the hot water storage tank is small, boiling is started by temporarily starting from a state where the remaining hot water amount is large. Since the amount of remaining hot water at the start of the next heating operation can be returned to normal, it is possible to obtain a heat pump type hot water heater that can save energy by operating energy saving.
[0029]
According to the heating control method for a heat pump type water heater according to claim 3 of the present invention, the amount of hot water used on the previous day is more than a predetermined amount compared to the amount of hot water used in the past, and if it is small, the heating operation is started. Therefore, even when the amount of heat stored in the hot water storage tank is small, the heating operation can be started from a state where the amount of residual hot water is large, and hot water shortage can be prevented.
[0030]
According to the heating control method for a heat pump type water heater of claim 4 according to the present invention, the amount of hot water used on the previous day is more than a predetermined amount compared to the amount of hot water used in the past, and if it is small, the heating operation is started. On the other hand, the amount of remaining hot water at the start of the next heating operation is changed to a normal small amount of remaining hot water, so if the amount of heat stored in the hot water storage tank is small, the heating operation is temporarily started from a state where the remaining hot water amount is large. The hot water can be prevented from running out and the amount of remaining hot water at the start of the next heating operation on the day returns to normal, so energy saving operation can be performed and the electricity bill can be reduced.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a configuration diagram of a heat pump type water heater showing Embodiment 1 of the present invention.
FIG. 2 is a block diagram of a control device according to Embodiment 1 of the present invention.
FIG. 3 is a flowchart of a boiling control operation in Embodiment 1 of the present invention.
FIG. 4 is a block diagram of a control device according to Embodiment 2 of the present invention.
FIG. 5 is a flowchart of a boiling control operation in Embodiment 2 of the present invention.
FIG. 6 is a configuration diagram of a conventional heat pump type water heater.
FIG. 7 is a configuration diagram of a conventional heat pump main body.
FIG. 8 is a block diagram of a control device in a conventional heat pump type water heater.
FIG. 9 is a flowchart of a conventional boiling water heating control operation.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Hot water heater main body, 2 Hot water storage tank, 5a Temperature sensor A, 5b Temperature sensor B, 6 Temperature sensor C, 8 Control part, 8a Heating operation start remaining hot water amount changing means, 8b Hot water amount storage means, 10 Heat pump main body.

Claims (4)

The liquid for hot water heated using the heat pump cycle, stored from the hot water storage tank upper part of the heated water heater body fluid back to the heat pump body is a heat source than the hot water storage tank bottom, the temperature of the liquid back to the heat Toponpu body In the heat pump water heater that stops the heating operation of the heat pump main body when the temperature reaches a predetermined temperature lower than the hot water storage temperature, and starts the heating operation of the heat pump main body when the remaining amount of hot water in the hot water storage tank falls below a predetermined amount. The amount of hot water used to store the amount of hot water used in the past, and when the amount of hot water used on the previous day is less than the predetermined amount of hot water stored in the amount of hot water stored in the used hot water storage means are changed by a large amount. A heat pump type hot water heater comprising heating operation start remaining hot water amount changing means. The liquid for hot water heated using the heat pump cycle, stored from the hot water storage tank upper part of the heated water heater body fluid back to the heat pump body is a heat source than the hot water storage tank bottom, the temperature of the liquid back to the heat Toponpu body In the heat pump water heater that stops the heating operation of the heat pump main body when the temperature reaches a predetermined temperature lower than the hot water storage temperature, and starts the heating operation of the heat pump main body when the remaining amount of hot water in the hot water storage tank falls below a predetermined amount. Used hot water storage means for storing past hot water usage, heating start remaining hot water storage means for storing past heating operation starting residual hot water volume, hot water usage for the day before the past hot water storage stored in said hot water storage means Is less than a predetermined amount, the amount of remaining hot water at the start of the heating operation is changed only once, and the remaining amount of hot water at the start of the subsequent heating operation is changed as described above. Heat pump water heater, characterized in that it comprises a heating operation start remaining hot water changing means for the stored past the remaining hot water in the starting remaining hot water storage unit. The liquid for hot water heated using the heat pump cycle, stored from the hot water storage tank upper part of the heated water heater body fluid back to the heat pump body is a heat source than the hot water storage tank bottom, the temperature of the liquid back to the heat Toponpu body Of the heat pump water heater that stops the heating operation of the heat pump main body when the temperature reaches a predetermined temperature lower than the hot water storage temperature, and starts the heating operation of the heat pump main body when the remaining hot water amount of the hot water storage tank becomes less than the predetermined amount. In the boiling control, a past amount of hot water used is memorized, and when the amount of hot water used on the previous day is less than a predetermined amount more than the past amount of used hot water, the amount of remaining hot water at the start of the heating operation is changed to be larger. Boil-up control method. The liquid for hot water heated using the heat pump cycle, stored from the hot water storage tank upper part of the heated water heater body fluid back to the heat pump body is a heat source than the hot water storage tank bottom, the temperature of the liquid back to the heat Toponpu body Of the heat pump water heater that stops the heating operation of the heat pump main body when the temperature reaches a predetermined temperature lower than the hot water storage temperature, and starts the heating operation of the heat pump main body when the remaining hot water amount of the hot water storage tank becomes less than the predetermined amount. In boiling control, the amount of hot water used in the past and the amount of hot water remaining at the start of the heating operation are stored, and when the amount of hot water used on the previous day is less than the predetermined amount of hot water, the amount of hot water at the start of the heating operation is determined only once. Heating-up control of a heat pump water heater, characterized in that the amount of remaining hot water after the start of heating operation is changed to the amount of hot water stored in the past. Law.

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