JP2011252675A - Heat pump water heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat pump water heater that can be re-heated with a power consumption less than the case of pouring hot water.SOLUTION: The heat pump water heater 1000 includes: a refrigerant circuit 101 with a high temperature side heat transfer pipe 2H constituting a compressor 1 and condenser 2, an expansion valve 3 and an evaporator 4, which are connected sequentially; a bathtub water circuit 301 with a bathtub 10, a bathtub water pump 11 and a low-temperature side heat transfer pipe 12L constituting a reheating heat exchanger 12, which are connected sequentially; a circulation hot water pump 6 and a low-temperature side heat transfer pipe 2L constituting the condenser 2; a circulation hot water heater circuit (reheating circuit) 202 with a selector valve 7 and a high temperature side heat transfer pipe 12H constituting the reheating heat exchanger 12, which are connected sequentially; a heating capacity controller 400 for controlling a heating capacity in the condenser 2 within a predetermined range, based on a difference between a target temperature of the bathtub water and a measured temperature thereof, when the bathtub water is heated in the reheating heat exchanger 12 by a circulation hot water heated in the condenser 2.

Description

  The present invention relates to a heat pump water heater, and more particularly, to a heat pump water heater that can keep bathtub water in a bathtub.

Conventional heat pump water heaters store hot water (hereinafter referred to as “hot water”) heated by inexpensive nighttime electricity in a hot water tank, supply the hot water to the bathtub, and when the supplied hot water cools, It was possible to whisper.
For example, a heat source circuit (refrigerant flows) that realizes a refrigeration cycle, a heating circuit (hot water flows) that is thermally connected to the heat source circuit by a condenser, and a heat exchanger that heats the heating circuit A connected bath water circuit (where bath water flows), and when the temperature of the bath water in the bath is lowered and heat retention (hereinafter referred to as “reheating”) is performed, additional heat exchange An invention is disclosed in which the heating efficiency (COP) is increased by reducing the temperature difference between the circulating hot water (gradually lowering temperature) and the bath water (gradually increasing temperature) in the process of heat exchange with the vessel ( For example, see Patent Document 1).

JP 2006-234314 A (pages 10-11, FIG. 1)

  However, the conventional heat pump water heater described in Patent Document 1 controls the temperature of the circulating hot water (water heated by the condenser) flowing into the reheating heat exchanger based on the temperature of the bath water. As the heating capacity increases, the amount of power consumed for carrying out the chasing increases. For this reason, there has been a problem that the amount of power consumption is larger than that in which heat is stored with hot water stored in a hot water tank (hereinafter referred to as “hot water pouring”).

  The present invention has been made to solve the above-mentioned problems. The power consumption necessary for securing the heating amount necessary for reheating is ensured, and the heating amount necessary for pouring the hot water is ensured. An object of the present invention is to provide a hot pump water heater capable of reducing the amount of power consumption required for the purpose.

The heat pump water heater according to the present invention is
A refrigerant circuit in which a compressor, a high-temperature side heat transfer tube constituting an condenser, an expansion valve, and an evaporator are sequentially connected by a refrigerant pipe;
A bathtub water circuit in which the low temperature side heat transfer pipes constituting the bathtub, the bathtub water pump and the additional heat exchanger are sequentially connected by the bathtub water piping;
A circulating hot water heating circuit in which a low temperature side heat transfer tube constituting the condenser, a high temperature side heat transfer tube constituting the follow-up heat exchanger, and a circulating hot water pump are sequentially connected by circulating hot water piping;
Heating capacity control means for controlling the heating capacity of the refrigerant circuit,
When the heating capacity control means heats the bathtub water flowing through the bathtub water pipe in the reheating heat exchanger with the circulating hot water flowing through the circulating hot water pipe heated in the condenser, Based on the difference between the temperature and the measured temperature, the heating capacity of the condenser is controlled within a predetermined range.

  According to the heat pump water heater according to the present invention, the amount of heating necessary for reheating (power consumption necessary for boiling the recirculated hot water to a predetermined temperature) is adjusted by adjusting the heat-retention heating capacity of the recirculated hot water during reheating operation. Amount) can be reduced compared to the heating amount necessary for pouring (when using the tank warm water stored in the hot water tank, the amount of power consumed for boiling the tank warm water to be used).

The circuit diagram which shows the structure of the heat pump water heater based on Embodiment of this invention. The circuit diagram which shows the structure of the heat pump water heater based on Embodiment of this invention. The control flowchart at the time of the chasing (heat retention) driving | operation of the heat pump water heater which concerns on embodiment of this invention. The characteristic view which shows the power consumption with respect to the heat retention heating capability of the heat pump water heater which concerns on embodiment of this invention.

1 to 4 are diagrams for explaining a heat pump water heater according to an embodiment of the present invention. FIG. 1 and FIG. 2 are circuit diagrams schematically showing the configuration, and FIG. FIG. 4 is a characteristic diagram illustrating the effect.
1 and 2, the heat pump water heater 1000 includes a heat pump unit 100, a hot water tank unit 200, a bathtub unit 300, and a measurement control device 400. Each will be described individually below.

(Heat pump unit)
The heat pump unit 100 includes a compressor 1, a condenser (which performs heat exchange between the refrigerant and water) 2, an expansion valve 3 and an evaporator (which performs heat exchange between the refrigerant and air) 4. These are sequentially connected by the refrigerant pipe 5 to form a circuit 101 through which the refrigerant circulates, so that the refrigeration cycle can be executed (more precisely, the high-temperature side heat transfer pipe 2H constituting the condenser 2 is the refrigerant circuit 101). Part of A fan 4 f that blows outside air is disposed opposite to the evaporator 4.
In addition, an outside air temperature sensor 13 c is provided at or near the outer periphery of the heat pump unit 100, and the outside air temperature around the heat pump unit 100 is measured.
Further, in the refrigerant circuit 101, the discharge temperature sensor 13 d is provided on the outlet side of the compressor 1, the suction temperature sensor 13 e is provided on the inlet side of the compressor 1, and the evaporation temperature sensor 13 f is provided at the intermediate portion from the inlet of the evaporator 4. The refrigerant temperature at each of the locations is measured.

The compressor drive device (not shown) uses an inverter-controlled DC brushless motor so that the rotation speed is variable so that the pressure and temperature of the refrigerant discharged from the compressor 1 can be changed. However, the overall capability may be made variable by combining a plurality of compressors and switching the combination. In addition, a structure such as a suction muffler that reduces refrigerant noise on the suction side of the compressor 1 or a device that collects lubricating oil that has flowed out to the discharge side of the compressor 1 may be added. .
As the refrigerant of the heat pump unit 100, a refrigerant that can be compressed to a high temperature, for example, a refrigerant such as carbon dioxide, R410A, propane, or propylene is suitable, but the present invention is not limited to these.

(Tub unit)
The bathtub unit 300 includes a bathtub 10, a bathtub water pump 11 that circulates bathtub water, and a reheating heat exchanger (heat exchange between bathtub water and circulating hot water described later) 12, and these are bathtub water pipes 9h. To 9j to form a bathtub water circuit 301 (more precisely, on the upstream side and the downstream side of the low-temperature side heat transfer pipe 12L constituting the reheating heat exchanger 12, respectively, on the downstream side of the bathtub water pipe 9h And the upstream side of the bathtub water pipe 9j is connected).
Moreover, the bathtub water temperature sensor 13k is provided in the bathtub 10, and the temperature of the bathtub water in a bathtub is measured. In the bathtub water circuit 301, the additional heat exchanger incoming water temperature sensor 13l and the additional heat exchanger hot water temperature sensor 13m are provided on the inlet side and the outlet side of the additional heat exchanger 12, respectively. The temperature of is measured.

(Hot water tank unit)
The hot water tank unit 200 includes a circulating hot water pump 6 that supplies water to the condenser 2, a hot water tank 8 that stores water heated by the condenser 2 (hereinafter referred to as “hot water”), and a flow path of the circulating water. And a switching valve (three-way valve) 7 for switching between.
That is, by switching the switching valve 7, the circulating hot water pump 6, the condenser 2 (more precisely, the low temperature side heat transfer pipe 2L constituting the condenser 2), the switching valve 7, and the reheating heat exchanger 12 (accurate) Are connected to the high-temperature side heat transfer pipe 12H constituting the reheating heat exchanger 12 and the circulating hot water pump 6 by circulating hot water pipes 9a, 9b, 9e, 9f, 9g, and a circulating hot water heating circuit (heating) Circuit) 202 is configured.
Furthermore, an inlet water temperature sensor 13a and an outlet water temperature sensor 13b are respectively provided on the inlet side and the outlet side of the condenser 2 (more precisely, the low temperature side heat transfer tube 2L constituting the condenser 2), and each of them circulates at the installation site. The water temperature is measured.

Further, by switching the switching valve 7, the circulating hot water pump 6, the condenser 2 (more precisely, the low temperature side heat transfer pipe 2L constituting the condenser 2), the switching valve 7, the hot water tank 8, and the circulating hot water pump. 6 are connected by the circulating hot water pipes 9a and 9b, the connecting pipes 9c and 9d, and the circulating hot water pipe 9g to form a hot water tank heating circuit (hot water supply circuit) 201.
Further, hot water tank temperature sensors 13g to 13j are provided on the surface of the hot water tank 8, and the temperature of the tank hot water stored in the hot water tank 8 is measured.

  In FIG. 1, for example, a connection pipe that directly supplies hot water of a constant temperature stored in the hot water tank 8 of the hot water tank heating circuit 201 to the bathtub 10, a kitchen (not shown), or the like, or water from a water source. Description of connection piping for supplying water from the hot water tank heating circuit 201 to the bathtub 10, kitchen (not shown), etc. is omitted.

(Measurement control device)
In the heat pump unit 100, a measurement control device 400 is provided as a control means. The measurement control device 400 is based on the measurement information measured by the temperature sensors 13a to 13m or the like and the content of the operation command information instructed by the remote control device (not shown) or the like from the user of the heat pump water heater 1000. The operation method of the compressor 1, the opening degree of the expansion valve 3, the operation method of the circulating hot water pump 6, the flow direction of the switching valve 7, the operation method of the bathtub water pump 11, the boiling operation, the reheating operation, and the like are controlled.

(Operation of boiling operation)
The operation of the boiling operation in the heat pump water heater 1000 will be described with reference to FIG.
In the boiling operation, the refrigerant circuit 101 and the hot water tank heating circuit 201 are operated (to be exact, the switching valve 7 is switched and the compressor 1 and the circulating hot water pump 6 are operated), and water is taken in at the bottom of the hot water tank 8. A relatively low temperature tank warm water flows out from the port 8b, is sent to the condenser 2, and heat exchange with the refrigerant is performed in the condenser 2 (the temperature of the refrigerant is transferred to the tank warm water) to increase the temperature of the tank warm water. In this operation, the hot water tank 8 is returned from the hot water storage port 8a to the hot water tank 8. In the figure, the connection piping in which the circulating water or bathtub water does not flow is indicated by broken lines.

That is, in the refrigerant circuit 101 of the heat pump unit 100, the temperature of the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 decreases while radiating heat (heats the tank hot water) to the hot water tank heating circuit 201 side in the condenser 2. At this time, if the pressure of the refrigerant is equal to or higher than the critical pressure, the refrigerant maintains a supercritical state (gas phase), lowers the temperature without causing a gas-liquid phase transition, and releases warm heat. On the other hand, if the pressure of the refrigerant is lower than the critical pressure, the gas-liquid phase transition occurs, so that the heat is released while liquefying.
That is, boiling (hot water supply heating) is performed by giving the heat radiated from the refrigerant to the load-side medium (here, the tank warm water flowing through the warm water tank heating circuit 201). The high-pressure refrigerant that has been boiled up and has flowed out of the condenser 2 and has fallen in temperature flows into the expansion valve 3.

The high-pressure refrigerant that has flowed into the expansion valve 3 is reduced in pressure to a low-pressure gas-liquid two-phase state.
Further, the refrigerant flowing out of the expansion valve 3 (depressurized and having a low temperature) flows into the evaporator 4, where it absorbs heat from the outside air (ambient air) and is vaporized into gas. The low-pressure refrigerant exiting the evaporator 4 is sucked into the compressor 1 and a refrigeration cycle in which the refrigerant circulates is executed.

  On the other hand, on the warm water tank unit 200 side, in the warm water tank heating circuit 201, the water in the warm water tank 8 passes from the water intake port 8b at the bottom of the warm water tank 8 through the connection pipe 9d and the circulating hot water pipe 9g. And is conveyed into the condenser 2 (low temperature side heat transfer tube 2L) via the circulating hot water pipe 9a. Then, it is heated (boiling) by exchanging heat with a high-temperature refrigerant, and passes through the circulating hot water pipe 9b, the switching valve 7, and the connecting pipe 9c, and enters the hot water tank 8 from the hot water storage port 8a above the hot water tank 8. Flow into. Thereby, the upper part of the hot water in the hot water tank 8 is in a high temperature state and the lower part is in a low temperature state.

(Control operation of boiling operation)
Next, the control operation of the boiling operation in this heat pump water heater will be described.
First, the operating capacity of the compressor 1 controlled by the number of revolutions and the like and the number of revolutions of the circulating hot water pump 6 are adjusted based on the heating capacity calculated by the measurement control device 400 described later.
That is, adjustment control is performed so that the heating capacity and the hot water temperature Tb (measured by the hot water temperature sensor 13b) of the tank hot water at the outlet of the low temperature side heat transfer tube 2L of the condenser 2 become a predetermined target value (Tb1). Is done. The target hot water temperature Tb1 is set from the operation command information instructed by the user from the remote controller, or is stored from the past hot water supply usage amount in the remote controller or by the microcomputer provided in the measurement control device 400. It is set so that energy (hot water storage amount) can be secured. The target hot water temperature Tb1 has a predetermined range, for example, a range of 65 ° C to 90 ° C.
If the predetermined heating capacity can be secured at the maximum value (for example, 90 ° C.) of the target hot water temperature Tb1, the predetermined heating capacity can be secured within the range of the target hot water temperature Tb1 (for example, 65 ° C. to 90 ° C.).

(Compressor control operation)
Therefore, as for the compressor 1 which is the heating capability of the condenser 2, the number of rotations thereof is, for example, the outside temperature Tc (measured by the outside temperature sensor 13c) and the tapping temperature Tb (tapping temperature sensor 13b) of the tank warm water as described above. The predetermined heating capacity can be ensured at any target hot water temperature Tb1.
In other words, the output of the compressor 1 is provided with a heating capacity that can ensure the hot water discharge temperature Tb of the tank warm water required as a “hot water supply” at any time under any external conditions. Tank hot water (hot water) having a desired temperature can be obtained as a “hot water supply device”.
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 compressor durability. For example, the rotation speed corresponds to a range of 40 to 100% of the rated capacity of the compressor 1. It is preferable.

(Expansion valve control operation)
The opening degree of the expansion valve 3 is controlled so that the discharge temperature Td (measured by the temperature sensor 13d) becomes a predetermined value (target discharge temperature Td1). The target discharge temperature Td1 is set to a temperature that is higher than the target hot water temperature Tb1 by “α [° C.]”, that is, “Td1 = Tb1 + α” in order to make the target hot water temperature Tb1 secure.
The value of “α” is, for example, a function of the outside air temperature Tc (measured by the temperature sensor 13c) and the target hot water temperature Tb1. Thus, the required hot water temperature Tb can be ensured by setting the target discharge temperature Td1 according to the target hot water temperature Tb1.
Further, from the viewpoint of the durability of the compressor 1 and the deterioration of the refrigerator oil, an upper limit temperature is usually provided for the discharge temperature Td.

(Pump control operation)
The rotation speed of the circulating hot water pump 6 is controlled so that the tapping temperature Tb becomes the target tapping temperature Tb1. In the expansion valve 3, since the discharge temperature Td is controlled to “target hot water temperature Tb1 + α [° C.]”, that is, the heating capacity on the refrigerant circuit 101 side is maintained constant, the hot water temperature Tb is reliably ensured. be able to.

(Operation of chasing operation)
With reference to FIG. 1, the operation of the chasing (warming) operation that is a characteristic part of the operation operation of the heat pump water heater 1000 will be described.
In the reheating operation, the refrigerant circuit 101, the circulating hot water heating circuit 202, and the bathtub water circuit 301 are simultaneously operated (more precisely, the switching valve 7 is switched, the compressor 1, the circulating hot water pump 6, and the bathtub water pump 11 are switched. Driving). In the figure, the connection piping where the circulating water does not flow is indicated by a broken line.
That is, the circulating hot water pipes 9a, 9b, 9e, 9f, and 9g forming the circulating hot water heating circuit 202 (the hot water tank 8 is separated), the low-temperature heat transfer pipe 2L of the condenser 2, and the reheating heat exchanger 12 The water stopped in the high-temperature side heat transfer pipe 12H (same as all tank hot water, except for the hot water tank 8 and the tank hot water stored in the connecting pipes 9c and 9d, hereinafter referred to as "circulated hot water"), It is circulated in the circulating hot water heating circuit 202.

At this time, in the refrigerant circuit 101, the circulating refrigerant flows into the condenser 2, and the heat is transferred to the circulating hot water circulating through the circulating hot water heating circuit 202 (cools the refrigerant).
In the circulating hot water heating circuit 202, the circulating hot water is circulated by the circulating hot water pump 6, the hot water is received from the refrigerant circulating in the refrigerant circuit 101 in the condenser 2 (heating the circulating hot water), and the reheating heat exchanger 12. , The hot water is transferred to the bathtub water circulating in the bathtub water circuit 301 (the circulating hot water is cooled).

  Further, in the bathtub water circuit 301, the bathtub water in the bathtub 10 is caused to flow into the reheating heat exchanger 12 by the bathtub water pump 11, and the recirculated hot water circulating in the recirculating hot water heating circuit 202 in the reheating heat exchanger 12. The heat is received from the tub, the bath water is heated and returned to the tub 10. Thereby, it will be in the state by which the temperature of the bathtub water in the bathtub 10 is kept constant (it keeps warm).

(Control operation for chasing operation)
Next, the control operation of the chasing (warming) operation in the heat pump water heater 1000 will be described. Since the operation control operation of the refrigerant circuit 101 of the heat pump unit 100 is the same as that in the boiling operation, the following describes the characteristic part of the reheating operation.
The operating capacity of the compressor 1 controlled by the rotational speed or the like is calculated by the measurement control device 400, and the incoming temperature Ta of the circulating hot water (measured and detected by the incoming water temperature sensor 13a) and the hot water temperature Tb of the circulating hot water (the outgoing hot water). The circulating hot water inlet / outlet temperature difference ΔTba (= Tb−Ta) with respect to (measured by the temperature sensor 13b) is adjusted and controlled so as to be within a predetermined range (this will be described in detail separately).

That is, the operation capacity of the compressor 1 is adjusted and controlled so that the heating capacity of the refrigerant circulating in the refrigerant circuit 101 is within a predetermined range.
The rotation speed of the circulating hot water pump 6 is adjusted and controlled so that the hot water temperature Tb becomes a predetermined hot water target hot water temperature Tb2. The chasing target hot water temperature Tb2 is set from the operation command information instructed by the user from the remote controller. Further, the range of the hot water target hot water temperature Tb2 is determined in advance, and is set, for example, in the range of 50 ° C to 70 ° C.

In the bathtub water circuit 301, the number of revolutions of the bathtub water pump 11 controlled by the number of revolutions is controlled at a constant number of revolutions, or the bath water incoming temperature Tl (additional temperature at the inlet of the reheating heat exchanger 12). The temperature difference (Tm-Tl) between the hot water exchanger incoming water temperature sensor 13l) and the tapping temperature Tm (measured and detected by the hot water exchanger hot water temperature sensor 13m) is a predetermined target temperature difference. It is controlled so as to be within ΔTml.
The target temperature difference ΔTml has a predetermined range, and is set, for example, in the range of 3 ° C. to 10 ° C.

(Control flow)
With reference to the flowchart shown in FIG. 3, the control operation of the chasing (warming) operation in the heat pump water heater 1000 will be described. Step j is described as “Sj”.
First, in step 1 (S1), the measurement control device 400 records the target temperature Tk1 for bath water designated by the user with a remote controller or the like.
Next, in step 2 (S2), the measurement control device 400 measures and records the bath water temperature Tk by the bath water temperature sensor 13k.
Further, in step 3 (S3), the measurement control device 400 calculates a temperature difference ΔTk (= Tk1−Tk) between the target heat retention temperature Tk1 and the bath water temperature Tk, and is equal to or less than a predetermined temperature difference ΔT1 (ΔTk ≦ ΔT1). If so, the process returns to step 2 after a lapse of a predetermined time, and if larger than the predetermined temperature difference ΔTk1 (ΔTk> ΔT1), the process proceeds to step 4 (S4).

In step 4 (S4), the measurement control device 400 sets a target hot water temperature Tb1 of the heat pump water heater 1000 during reheating.
In step 5 (S5), the measurement control device 400 sets the frequency of the compressor 1 of the heat pump water heater during reheating.
In step 6 (S6), the measurement control device 400 starts operation of the heat pump water heater.

In step 7 (S7) after the lapse of a certain time, the measurement control device 400 measures the incoming temperature Ta of the circulating hot water (measured and detected by the incoming water temperature sensor 13a) and the outgoing hot water temperature Tb (measured by the temperature sensor 13b). And the circulating hot water inlet / outlet temperature difference ΔTba (= Tb−Ta).
When the circulating hot water inlet / outlet temperature difference ΔTba is smaller than the predetermined value ΔT2 (ΔTba <ΔT2), the process proceeds to step 8 (S8), the frequency of the compressor 1 is increased, and after a predetermined time has elapsed, the process returns to step 7 (S7).
On the other hand, when the circulating hot water inlet / outlet temperature difference ΔTba is larger than the predetermined value ΔT3 (ΔTba> ΔT3), the process proceeds to step 8 (S8), the frequency of the compressor 1 is decreased, and the process returns to step 7 (S7) after a predetermined time has elapsed. .

  In step 7 (S7), when the circulating hot water inlet / outlet temperature difference ΔTba is within a certain range (ΔT2 ≦ ΔTba ≦ ΔT3), the process proceeds to step 9 (S9) after a certain period of time. The water temperature sensor 13k detects the bathtub water temperature Tk again.

In Step 10 (S10), the measurement control device 400 calculates a temperature difference ΔTk (= Tk1−Tk) between the target heat retention temperature Tk1 and the bath water temperature Tk. If the temperature difference ΔTk is within a predetermined range (ΔT4 ≦ ΔTk ≦ ΔT5), the operation of the heat pump water heater 1000 is stopped in step 11 (S11), and the chasing operation is ended.
On the other hand, if the temperature difference ΔTk is not within the predetermined range (ΔTk <ΔT4, ΔT5 <ΔTk), after a predetermined time has elapsed, the process returns to step 7 (S7) to continue the chasing operation.

  According to the embodiment of the present invention, when the bathtub water of the bathtub 10 is chased by the heat transferred from the circulating hot water (heated by the heat in the refrigeration cycle) (heat-retained), the heat pump water heater 1000 can be added. Compared with the case where the hot water heated by night electricity stored in the hot water tank 8 is directly supplied to the bathtub 10 (pour hot water) by controlling the watering ability (heat insulation heating ability), it is necessary for heat insulation. It is possible to reliably reduce the amount of power consumption required to secure the heating amount.

In FIG. 4, heat insulation using the reheating operation with circulating hot water according to the present invention for the heat insulation heating capacity of the bath water and conventional hot water pouring (the tank hot water heated by the night electricity stored in the hot water tank 8 is taken into the bathtub 10. Power supply with heat retention by direct supply).
Therefore, when the temperature of the circulating hot water of the present invention (the hot water temperature Tb) is fixed and the heat retention heating capacity is used as a parameter, the power consumption of heat retention using the circulating hot water of the present invention with a heating capacity within a specific range is conventionally It is smaller than the amount of power consumed by pouring hot water.
In other words, by maintaining the temperature of the bath water with the heat-retaining and heating capacity (replacement capacity) within this range, the amount of power consumed for heat retention using the circulating hot water can be reduced for hot water pouring (heat retention using the tank warm water). It can be made smaller than the amount of power consumed when boiling the hot water in the tank at night.

  Since the heat pump water heater according to the present invention is as described above, the heat pump water heater can be used as various heat pump water heaters that require bath water insulation of a bathtub.

  1: compressor, 2: condenser, 2H: high temperature side heat transfer tube, 2L: low temperature side heat transfer tube, 3: expansion valve, 4: evaporator, 4f: fan, 5: refrigerant piping, 6: circulating hot water pump, 7 : Switching valve, 8: hot water tank, 8a: hot water storage port, 8b: intake port, 9a: circulating hot water piping, 9b: circulating hot water piping, 9c: connecting piping, 9d: connecting piping, 9e: circulating hot water piping, 9f: circulating Hot water piping, 9 g: circulating hot water piping, 10: bathtub, 11: bathtub water pump, 12: reheating heat exchanger, 12H: high temperature side heat transfer tube, 12L: low temperature side heat transfer tube, 13a: incoming water temperature sensor, 13b: outgoing hot water Temperature sensor, 13c: Outside air temperature sensor, 13d: Discharge temperature sensor, 13e: Suction temperature sensor, 13f: Evaporation temperature sensor, 13g-13j: Hot water tank temperature sensor, 13k: Bath water temperature sensor, 13l: Reheating heat exchange Incoming water temperature sensor, 13 m: reheating heat exchanger hot water temperature sensor, 100: heat pump unit, 101: refrigerant circuit, 200: hot water tank unit, 201: hot water tank heating circuit, 202: circulating hot water heating circuit, 300: bathtub unit, 301: Bath water circuit, 400: Measurement control device, 1000: Heat pump water heater, Ta: Incoming water temperature, Tb: Outlet temperature, Tb1: Target hot water temperature, Tb2: Target hot water temperature, Tc: Outside air temperature, Td: Discharge temperature Td1: target discharge temperature, Tk: bath water temperature, Tk1: target heat retention temperature, Tl: incoming water temperature, Tm: hot water temperature, ΔT1: temperature difference, ΔT2: predetermined value, ΔT3: predetermined value, ΔTba: circulating hot water inlet / outlet temperature difference , ΔTk: temperature difference, ΔTml: target temperature difference.

Claims (4)

A refrigerant circuit in which a compressor, a high-temperature side heat transfer tube constituting an condenser, an expansion valve, and an evaporator are sequentially connected by a refrigerant pipe;
A bathtub water circuit in which the low temperature side heat transfer pipes constituting the bathtub, the bathtub water pump and the additional heat exchanger are sequentially connected by the bathtub water piping;
A circulating hot water heating circuit in which a low temperature side heat transfer tube constituting the condenser, a high temperature side heat transfer tube constituting the follow-up heat exchanger, and a circulating hot water pump are sequentially connected by circulating hot water piping;
Heating capacity control means for controlling the heating capacity of the refrigerant circuit,
When the heating capacity control means heats the bathtub water flowing through the bathtub water pipe in the reheating heat exchanger with the circulating hot water flowing through the circulating hot water pipe heated in the condenser, A heat pump water heater, wherein the heating capacity of the condenser is controlled within a predetermined range based on a difference between a temperature and a measured temperature.   The heating capacity control means controls the rotation speed of the compressor while keeping the rotation speed of the circulating hot water pump constant when controlling the heating capacity of the condenser to a predetermined range. The heat pump water heater according to 1.   The heat pump water heater according to claim 1 or 2, wherein the predetermined range of the controlled heating capacity in the condenser corresponds to a range of 40 to 100% of a rated capacity of the compressor.   The circulating hot water piping of the circulating hot water heating circuit is branched at the inlet side and the outlet side of the additional heat exchanger, respectively, and the hot water tank is connected to the branched inlet side branch portion and the outlet side branch portion via the connection piping. The heat pump water heater according to any one of claims 1 to 3, wherein a switching valve is installed in at least one of the inlet-side branch portion or the outlet-side branch portion.

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