JP2005300057A - Heat pump water heater - Google Patents

Abstract

An object of the present invention is to provide a heat pump water heater capable of supplying hot water by effectively using the capacity of a hot water tank with low power consumption.
A refrigerant circuit in which a compression means 31, a main hot water supply heat exchanger 32, a main decompression means 33, and an evaporator 34 are sequentially connected, a hot water storage means 36, a circulation means 37, and the main hot water supply heat exchange. A hot water supply circuit in which the heaters 32 are sequentially connected, and an opening / closing means 38 and a sub decompression means 40 are provided between the compression means 31 and the hot water supply heat exchanger 32 and between the compression means 31 and the evaporator 34. Are connected in series, and even when the incoming water temperature becomes high, the refrigerant discharged from the compression means 31 is bypassed to the low pressure side. The hot water can be easily heated to a high temperature while reducing the temperature, and the heat pump can be operated safely and efficiently.
[Selection] Figure 1

Description

  The present invention relates to a hot water storage type heat pump hot water supply apparatus.

  Conventionally, this type of heat pump water heater is shown in FIG. FIG. 4 is a cycle configuration diagram of a conventional heat pump water heater. In FIG. 4, a refrigerant circulation circuit comprising a compressor 1, a hot water supply heat exchanger 2, an expansion device 3, and an evaporator 4, a hot water tank 5, a circulation pump 6, the hot water supply heat exchanger 2, and an auxiliary heater 19 are provided. The high-temperature and high-pressure superheated gas refrigerant discharged from the compressor 1 flows into the hot water supply heat exchanger 2 and heats the hot water supplied from the circulation pump 6.

The condensed and liquefied refrigerant is decompressed by the expansion device 3 and flows into the evaporator 4, where it absorbs atmospheric heat to evaporate and returns to the compressor 1. On the other hand, the hot water heated by the hot water supply heat exchanger 2 flows into the upper part of the hot water storage tank 5 and is gradually stored from above. When the inlet water temperature of the hot water supply heat exchanger 2 reaches a set value, the water temperature detector 20 detects it, stops the heat pump operation by the compressor 1, and switches to the independent operation of the auxiliary heater 19. Yes (see, for example, Patent Document 1).
JP 60-164157 A

  However, in the conventional configuration as described above, a hot water mixed layer is formed at the portion where the hot water in the hot water tank 5 is in contact with water as the boiling operation time elapses, and the layer gradually expands. This occurs due to heat conduction and convection in high temperature hot water and low temperature water. Heat is transferred from the high temperature hot water to the low temperature water, and the temperature of the high temperature hot water decreases at the boundary portion, while the temperature of the low temperature water increases.

  Accordingly, when the boiling operation is almost completed, the temperature of the water flowing into the hot water supply heat exchanger 2 becomes high, so that the discharge pressure and the discharge temperature of the compressor 1 rise, and the winding of the motor of the compressor 1 The durability of the compressor 1, such as a rise in temperature, has been a problem.

  Therefore, since the operation was stopped in a state where the temperature of the water flowing into the hot water supply heat exchanger was low, the operation was stopped with the lower part of the hot water tank 5 being in a state of low temperature water, and the hot water in the hot water tank 5 was The capacity could not be used effectively, and the amount of hot water stored was decreasing.

  In addition, in order to increase the amount of stored hot water, after stopping the heat pump operation, when the amount of stored hot water is increased by the independent operation of the auxiliary heater 19, heating is performed by an electric heater, so that power consumption increases and efficiency decreases. It was.

  This invention solves the said conventional subject, and it aims at providing the heat pump water heater which can supply hot water using the capacity | capacitance of a hot water tank effectively with low power consumption.

In order to solve the above-described conventional problems, a heat pump hot water supply apparatus of the present invention includes a compression means for compressing refrigerant, a heat exchanger for main hot water supply, a main decompression means, a refrigerant circuit in which an evaporator is sequentially connected, hot water storage means, circulation And a hot water supply circuit in which the main hot water supply heat exchangers are sequentially connected, and an open / close means and a sub-reduced pressure between the compression means and the hot water heat exchanger, and between the compression means and the evaporator. In order to bypass the refrigerant discharged from the compression means to the low-pressure side even when the incoming water temperature becomes close to completion of the boiling operation, the refrigerant is bypassed. While reducing the discharge pressure and discharge temperature of the compression means of the circuit, the hot water can be easily heated to a high temperature, and the heat pump can be operated safely and efficiently. Moreover, hot water can be stored up to the lower part of the hot water tank, and the capacity of the hot water tank can be used effectively.

  ADVANTAGE OF THE INVENTION According to this invention, the heat pump water heater which can supply hot water using the capacity | capacitance of a hot water storage tank effectively with low power consumption can be provided.

  The first aspect of the present invention sequentially connects a refrigerant circuit in which a compression means for compressing refrigerant, a main hot water supply heat exchanger, a main decompression means, an evaporator are connected in sequence, a hot water storage means, a circulation means, and the main hot water supply heat exchanger. A sub-circuit for connecting between the compression means and the heat exchanger for hot water supply and between the compression means and the evaporator via an opening / closing means and a sub-pressure reduction means in series. In order to bypass the refrigerant discharged from the compression means to the low pressure side even when the incoming water temperature becomes close to the completion of the boiling operation, the discharge pressure and discharge temperature of the compression means of the refrigerant circuit are reduced. While hot water can be easily heated to a high temperature, the heat pump can be operated safely and with high efficiency. Moreover, hot water can be stored up to the bottom of the hot water tank, and the capacity of the hot water tank can be used effectively.

  According to a second aspect of the present invention, a sub-hot water supply heat exchanger is provided in the sub-circuit, and when the water temperature is high, the refrigerant discharged from the compression means is cooled by the sub-hot water heat exchanger, and the refrigerant therein A large amount can be retained, and the amount of refrigerant present in the main circuit can be reduced, so that the discharge pressure and discharge temperature of the compression means can be reduced.

  3rd invention connects the water outlet piping of the heat exchanger for sub-hot water supply, and the water inlet piping of the heat exchanger for main hot water supply, does not require a switching valve in a water side circuit, and has high inlet water temperature In this case, the temperature can be lowered by the heat exchanger for auxiliary hot water supply so that a large amount of refrigerant can be held there, and the amount of refrigerant existing in the main circuit is reduced to reduce the discharge pressure and discharge temperature of the compression means. be able to.

  According to a fourth aspect of the present invention, the passage resistance between the opening / closing means and the sub decompression means is made smaller than the passage resistance between the evaporator and the compression means, and the refrigerant discharged from the compression means when the water temperature is high. By bypassing to the low pressure side, a large amount of refrigerant can be retained between the opening / closing means and the sub pressure reducing means of the sub circuit, and the refrigerant amount existing in the main circuit is reduced to reduce the discharge pressure and discharge of the compression means. The temperature can be reduced.

  According to a fifth aspect of the present invention, an auxiliary heat exchanger for exchanging heat with the outside air is provided between the opening / closing means and the auxiliary pressure reducing means. When the water temperature is high, the refrigerant discharged from the compression means is exchanged with the outside air. Thus, the temperature can be lowered and a large amount of refrigerant can be retained, and the amount of refrigerant present in the main circuit can be reduced to reduce the discharge pressure and discharge temperature of the compression means.

  In the sixth aspect of the invention, the auxiliary heat exchanger is formed integrally with the evaporator, and a fan for blowing outside air to the evaporator can be shared, and the discharge of the compression means can be performed without increasing the size of the apparatus. Pressure and discharge temperature can be reduced. Moreover, the heat quantity of a high temperature refrigerant | coolant can be given to an evaporator at the time of a defrost, and a defrost time can be shortened.

  The seventh invention is configured to exchange heat between the opening / closing means and the sub-decompression means and between the main decompression means and the compression means.When the water temperature is high, the refrigerant discharged from the compression means is Heat exchange with a low-temperature main circuit refrigerant can lower the temperature and retain a large amount of refrigerant there, and the amount of refrigerant present in the main circuit can be reduced to reduce the discharge pressure and discharge temperature of the compression means Can do.

  The eighth invention comprises a control device for controlling the operation of the opening / closing means, and opens the opening / closing means when the water inlet temperature of the heat exchanger for hot water supply exceeds a predetermined value. High-efficiency operation is possible, and it is possible to bypass the refrigerant discharged from the compression means to the low-pressure side only when the incoming water temperature becomes high near the completion of the boiling operation. Safe operation that reduces temperature is possible.

  The ninth aspect of the invention uses carbon dioxide gas as a refrigerant, achieves high temperature of hot water supply with high efficiency, and even when the refrigerant leaks to the outside, the influence on global warming is very small.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 shows a configuration diagram of a heat pump water heater in the first embodiment of the present invention.

  In FIG. 1, a compressor 31, which is a compression means for compressing a refrigerant, a heat exchanger 32 for hot water supply, a main throttle device 33, which is a main decompression means, and an evaporator 34 are sequentially connected in an annular manner, and carbon dioxide is enclosed as the refrigerant. Thus, a refrigerant circulation circuit is formed, and the evaporator 34 includes a fan 35 that is a blowing means for blowing outside air. Further, a hot water supply circuit is formed in which a hot water storage tank 36, a circulation pump 37 that is a circulation means, and a heat exchanger 32 for hot water supply are connected in order, and the high-temperature and high-pressure superheated gas refrigerant discharged from the compressor 31 is the heat for hot water supply. It flows into the exchanger 32 and heats the hot water supplied from the circulation pump 37 here.

  Further, the piping between the compressor 31 and the hot water supply heat exchanger 32 is branched to provide an on-off valve 38 as an opening / closing means, a heat exchanger 39 for auxiliary hot water supply, and a sub throttle device 40 as a sub pressure reducing means. A sub-circuit connected to the piping between the evaporator 34 and the compressor 31 is formed in order.

  The hot water supplied from the circulation pump 37 is first heated by the sub-hot water heat exchanger 39 and then further heated by the hot water heat exchanger 32. In addition, an incoming water temperature sensor 41 for detecting the incoming water temperature flowing into the auxiliary hot water supply heat exchanger 39 is provided, and the control for controlling the opening / closing of the on-off valve 38 in comparison with a predetermined temperature set in advance. A device 42 is installed. Further, carbon dioxide gas is sealed as the refrigerant.

  About the heat pump hot-water supply apparatus comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  The refrigerant (carbon dioxide gas) compressed to a supercritical state of high temperature and high pressure by the compressor 31 exchanges heat with water flowing through the hot water supply circuit in the hot water supply heat exchanger 32, and becomes a medium temperature and high pressure refrigerant itself. Then, the refrigerant flows into the evaporator 34 and exchanges heat with the outside air blown by the fan 35 to evaporate and return to the compressor 1. On the other hand, the hot water supplied by the circulation pump 37 passes through the sub-hot water heat exchanger 39 and is heated by the hot water heat exchanger 32, and the generated hot water flows into the upper part of the hot water storage tank 36, gradually from above. Hot water is being stored.

  On the other hand, as the boiling operation time elapses, a hot water mixed layer is formed at the portion where the hot water in the hot water tank 36 is in contact with water, and the layer expands to the lower part of the hot water tank 36, and when the boiling operation is nearly completed, The temperature of the water flowing into the sub-hot water supply heat exchanger 39 and the hot water supply heat exchanger 32 through the circulation pump 37 from the lower part 36 becomes higher.

  In this case, when the incoming water temperature detected by the incoming water temperature sensor 41 rises above a predetermined temperature preset in the control device 42, the on-off valve 38 is operated to open. By doing so, a part of the high-temperature and high-pressure refrigerant discharged from the compressor 31 passes through the on-off valve 38 and flows into the auxiliary hot water supply heat exchanger 39. The remaining refrigerant contributes to hot water supply in the main hot water supply heat exchanger 32, passes through the main throttle device 33 and the evaporator 34, exchanges heat with the outside air blown by the fan 35, and becomes evaporative gas.

  The refrigerant that has flowed into the auxiliary hot water supply heat exchanger 39 exchanges heat with the hot water supplied from the circulation pump 37 here, and the temperature of the refrigerant decreases, and the refrigerant becomes a high-density refrigerant and flows into the auxiliary throttle device 40. Here, the pressure is reduced to a low pressure, and the refrigerant merged with the refrigerant exiting the evaporator 34 and sucked into the compressor 31 again.

  On the other hand, the hot water supplied from the circulation pump 37 is first heated by the sub-hot water heat exchanger 39 and then heated to a high temperature by the main hot water heat exchanger 32, and the generated hot water is placed in the upper part of the hot water tank 36. It flows in and is gradually stored from above. Here, since the temperature of the refrigerant flowing into the sub-hot water supply heat exchanger 39 is low, the refrigerant exists as a high-density refrigerant, and the remaining refrigerant circulates through the main circuit.

  On the other hand, when the temperature of the hot water supply flowing into the main hot water supply heat exchanger 32 becomes higher in this way, the refrigerant outlet temperature of the main hot water supply heat exchanger 32 also becomes higher, so the discharge pressure of the compressor 31 increases. As a result, the refrigeration cycle balances and the discharge temperature rises accordingly.

  In this embodiment, in such a case, by operating the opening / closing valve 38 in the opening direction, a part of the high-temperature / high-pressure refrigerant discharged from the compressor 31 passes through the opening / closing valve 38 and performs heat exchange for the auxiliary hot water supply. In order to contribute to hot water by flowing into the heater 39, the refrigerant temperature of the sub-hot water heat exchanger 39 can be lowered, and a large amount of refrigerant can be held there, and the amount of refrigerant present in the main circuit is reduced, The discharge pressure and discharge temperature of the compressor can be reduced.

  Therefore, the hot water can be easily heated to a high temperature, and the heat pump can be operated safely and efficiently. Moreover, hot water can be stored up to the lower part of the hot water tank 36, and the capacity of the hot water tank can be effectively used.

(Embodiment 2)
FIG. 2 shows a configuration diagram of a heat pump hot-water supply apparatus in the second embodiment of the present invention. The same parts shown in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In the present embodiment, the piping between the compressor 31 and the main hot water supply heat exchanger 32 branches, and the switching valve 50, the auxiliary heat exchanger 51 for exchanging heat with the outside air, and the sub-throttle device 52 are sequentially provided. Thus, a sub-circuit connected to the piping between the evaporator 34 and the compressor 31 is configured.

  In addition, an incoming water temperature sensor 53 for detecting the incoming water temperature flowing into the main hot water supply heat exchanger 32 is provided, and the opening / closing valve 50 is controlled to be opened and closed by comparing the incoming water temperature with a preset temperature. A device 54 is installed. Further, carbon dioxide gas is sealed as the refrigerant.

  About the heat pump hot-water supply apparatus comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

The refrigerant (carbon dioxide gas) compressed to a supercritical state of high temperature and high pressure by the compressor 31 exchanges heat with water flowing through the hot water supply circuit in the hot water supply heat exchanger 32, and becomes a medium temperature and high pressure refrigerant itself. Then, the refrigerant flows into the evaporator 34 and exchanges heat with the outside air blown by the fan 35 to evaporate and return to the compressor 1. On the other hand, the hot water supplied by the circulation pump 37 is heated by the heat exchanger 32 for main hot water supply, and the generated hot water flows into the upper part of the hot water storage tank 36 and is gradually stored from above.

  On the other hand, as the boiling operation time elapses, a hot water mixed layer is formed at the portion where the hot water in the hot water tank 36 is in contact with water, and the layer expands to the lower part of the hot water tank 36, and when the boiling operation is nearly completed, The temperature of water flowing into the main hot water supply heat exchanger 32 through the circulation pump 37 from the lower part 36 becomes higher.

  In this case, when the incoming water temperature detected by the incoming water temperature sensor 53 rises above the temperature preset in the control device 54, the on-off valve 50 is operated to open. As a result, a part of the high-temperature and high-pressure refrigerant discharged from the compressor 31 flows into the auxiliary heat exchanger 51 through the on-off valve 50. The remaining refrigerant contributes to hot water supply in the main hot water supply heat exchanger 32, passes through the main throttle device 33 and the evaporator 34, exchanges heat with the outside air blown by the fan 35, and becomes evaporative gas.

  The refrigerant flowing into the auxiliary heat exchanger 51 exchanges heat with the outside air sent from the fan 35 here, the temperature of the refrigerant decreases, and the refrigerant becomes a high-density refrigerant and flows into the sub-throttle device 52, where the low pressure The refrigerant is discharged to the compressor 31, merged with the refrigerant exiting the evaporator 34, and sucked into the compressor 31 again. Here, since the temperature of the refrigerant flowing into the auxiliary hot water supply heat exchanger 51 is low, the refrigerant exists as a high-density refrigerant, and the remaining refrigerant circulates through the main circuit.

  On the other hand, when the temperature of the hot water supply flowing into the main hot water supply heat exchanger 32 becomes higher in this way, the refrigerant outlet temperature of the main hot water supply heat exchanger 32 also becomes higher, so the discharge pressure of the compressor 31 increases. As a result, the refrigeration cycle balances and the discharge temperature rises accordingly.

  In this embodiment, in such a case, by operating the opening / closing valve 50 in the opening direction, a part of the high-temperature / high-pressure refrigerant discharged from the compressor 31 passes through the opening / closing valve 50 and the auxiliary heat exchanger 51. It is possible to reduce the refrigerant temperature in the main circuit by reducing the refrigerant temperature and reduce the refrigerant amount existing in the main circuit, thereby reducing the discharge pressure and discharge temperature of the compressor 31.

  Therefore, the hot water can be easily heated to a high temperature, and the heat pump can be operated safely and efficiently. Moreover, hot water can be stored up to the lower part of the hot water tank 36, and the capacity of the hot water tank can be effectively used.

  Here, the auxiliary heat exchanger 51 is preferably formed integrally with the evaporator 34. That is, a part of the evaporator 34, which is a so-called fin-and-tube heat exchanger composed of tubes and fins, is used as the auxiliary heat exchanger 51 by allowing the refrigerant that has exited the on-off valve 50 to flow in. By doing so, there is no need to separately install the auxiliary heat exchanger 51, and the apparatus can be miniaturized.

(Embodiment 3)
FIG. 3 shows a configuration diagram of a heat pump hot-water supply apparatus according to the third embodiment of the present invention. The same parts shown in the above embodiment are given the same numbers, and the description thereof is omitted.

  In the present embodiment, the piping between the compressor 31 and the main hot water supply heat exchanger 32 branches, the on-off valve 60, the auxiliary heat exchanger 61 that exchanges heat with the inlet piping of the evaporator 34, and the sub-throttle. A sub-circuit connected to the piping between the evaporator 34 and the compressor 31 through the device 62 in order is configured.

  In addition, an incoming water temperature sensor 63 for detecting the incoming water temperature flowing into the main hot water supply heat exchanger 32 is provided, and the control for controlling the opening and closing of the on-off valve 60 by comparing the incoming water temperature with a preset temperature. A device 54 is installed. Further, carbon dioxide gas is sealed as the refrigerant.

  About the heat pump hot-water supply apparatus comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  The refrigerant (carbon dioxide gas) compressed to a supercritical state of high temperature and high pressure by the compressor 31 exchanges heat with water flowing through the hot water supply circuit in the hot water supply heat exchanger 32, and becomes a medium temperature and high pressure refrigerant itself. Then, the refrigerant flows into the evaporator 34 and exchanges heat with the outside air blown by the fan 35 to evaporate and return to the compressor 1. On the other hand, the hot water supplied by the circulation pump 37 is heated by the heat exchanger 32 for main hot water supply, and the generated hot water flows into the upper part of the hot water storage tank 36 and is gradually stored from above.

  On the other hand, as the boiling operation time elapses, a hot water mixed layer is formed at the portion where the hot water in the hot water tank 36 is in contact with water, and the layer expands to the lower part of the hot water tank 36, and when the boiling operation is nearly completed, The temperature of water flowing into the main hot water supply heat exchanger 32 through the circulation pump 37 from the lower part 36 becomes higher.

  In this case, when the incoming water temperature detected by the incoming water temperature sensor 63 rises above the temperature preset in the control device 64, the on-off valve 60 is operated in the opening direction. As a result, a part of the high-temperature and high-pressure refrigerant discharged from the compressor 31 flows into the auxiliary heat exchanger 61 through the on-off valve 60. The remaining refrigerant contributes to hot water supply in the main hot water supply heat exchanger 32, passes through the main throttle device 33 and the evaporator 34, exchanges heat with the outside air blown by the fan 35, and becomes evaporative gas.

  The refrigerant that has flowed into the auxiliary heat exchanger 61 indirectly exchanges heat with the low-temperature refrigerant that has exited the main throttle device 33 here, and the temperature of the refrigerant decreases, and the refrigerant becomes a high-density refrigerant and enters the sub-throttle device 62. The refrigerant flows in, is decompressed to a low pressure, merges with the refrigerant exiting the evaporator 34, and is sucked into the compressor 31 again.

  Here, since the refrigerant flowing into the auxiliary hot water supply heat exchanger 61 has a low temperature, it exists as a high-density refrigerant, and the remaining refrigerant circulates through the main circuit.

  On the other hand, when the temperature of the hot water supply flowing into the main hot water supply heat exchanger 32 becomes higher in this way, the refrigerant outlet temperature of the main hot water supply heat exchanger 32 also becomes higher, so the discharge pressure of the compressor 31 increases. As a result, the refrigeration cycle balances and the discharge temperature rises accordingly.

  In this embodiment, in such a case, by operating the opening / closing valve 60 in the opening direction, a part of the high-temperature and high-pressure refrigerant discharged from the compressor 31 passes through the opening / closing valve 60 and the auxiliary heat exchanger 61. It is possible to reduce the refrigerant temperature in the main circuit by reducing the refrigerant temperature and reduce the refrigerant amount existing in the main circuit, thereby reducing the discharge pressure and discharge temperature of the compressor 31.

  Therefore, the hot water can be easily heated to a high temperature, and the heat pump can be operated safely and efficiently. Moreover, hot water can be stored up to the lower part of the hot water tank 36, and the capacity of the hot water tank can be effectively used.

Here, the auxiliary heat exchanger 61 may have a configuration in which a tube and a tube are brazed, a configuration of a double tube, and the like, which are all included in the present invention.

  As described above, the heat pump hot water supply apparatus according to the present invention can easily heat the hot water supply to a high temperature while reducing the discharge pressure and discharge temperature of the compressor of the refrigerant circuit. It is useful for a heat pump water heater to be obtained and an air conditioner for obtaining high temperature air.

The block diagram of the heat pump hot-water supply apparatus in Embodiment 1 of this invention The block diagram of the heat pump hot-water supply apparatus in Embodiment 2 of this invention The block diagram of the heat pump hot-water supply apparatus in Embodiment 3 of this invention Configuration diagram of conventional heat pump water heater

Explanation of symbols

31 Compressor (compression means)
32 Heat exchanger for main hot water supply 33 Main throttle device (main decompression means)
34 Evaporator 35 Fan 36 Hot water storage tank (hot water storage means)
37 Circulation pump (circulation means)
38, 50, 60 Open / close valve (open / close means)
39 Heat exchanger for sub-hot water supply 40, 52, 62 Sub-throttle device (sub-pressure reduction means)
41, 53, 63 Inlet temperature sensor 42, 54, 64 Control device 51, 61 Auxiliary heat exchanger

Claims (9)

Compressor means for compressing refrigerant, heat exchanger for main hot water supply, main decompression means, refrigerant circuit sequentially connected with evaporator, hot water storage means, circulation means, and hot water supply circuit sequentially connected with main heat exchanger for hot water supply A heat pump hot water supply apparatus provided with a subcircuit that connects between the compression means and the hot water heat exchanger and between the compression means and the evaporator via an opening / closing means and a sub pressure reduction means in series. The heat pump hot-water supply apparatus of Claim 1 which provided the heat exchanger for sub-hot-water supply in the subcircuit. The heat pump hot-water supply apparatus of Claim 2 which connects the water outlet piping of the heat exchanger for auxiliary hot water supply, and the water inlet piping of the heat exchanger for main hot water supply. The heat pump hot water supply apparatus according to claim 1, wherein the passage resistance between the opening / closing means and the sub-decompression means is smaller than the passage resistance between the evaporator and the compression means. The heat pump hot water supply apparatus according to claim 1, wherein an auxiliary heat exchanger for exchanging heat with the outside air is provided between the opening / closing means and the sub-decompression means. The heat pump hot water supply apparatus according to claim 5, wherein the auxiliary heat exchanger is formed integrally with the evaporator. The heat pump hot water supply apparatus according to claim 1, wherein heat exchange is performed between the opening / closing means and the sub pressure reducing means and between the main pressure reducing means and the compression means. The control device for controlling the operation of the opening / closing means is provided, and the opening / closing means is opened when the water inlet temperature of the heat exchanger for hot water supply reaches a predetermined value or higher. Heat pump water heater. The heat pump hot-water supply apparatus of any one of Claims 1-8 which uses a carbon dioxide gas as a refrigerant | coolant.

Images