JP2011153723A - Refrigerating cycle apparatus and heat pump water heater using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigerating cycle apparatus that operates with high energy efficiency, by preventing heat leakage from a compressor, and by controlling heat transfer from a first refrigerant piping to a second refrigerant piping during defrosting operation. <P>SOLUTION: A refrigerating cycle apparatus includes: a refrigerant circuit 5 that is formed by sequentially connecting a compressor 1, a radiator 2, a decompression mechanism 3, and an evaporator 4 which exchanges heat between air and a refrigerant; a first refrigerant piping that is part of the refrigerant circuit 5 and supplies a refrigerant from the radiator 2 to the evaporator 4; and a second refrigerant piping that supplies a refrigerant from the evaporator 4 to the compressor 1. The refrigerating cycle apparatus is provided with a first heat insulating material 9 between the compressor 1 and the second circuit piping; a second heat insulating 10 between the fist refrigerant piping and the second refrigerating piping. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a refrigeration cycle apparatus.

  Conventionally, this type of refrigeration cycle apparatus is typically used as a refrigeration cycle apparatus equipped with a heat pump water heater as shown in FIG. Therefore, below, the conventional structure and operation | movement are demonstrated taking the example of the refrigerating-cycle apparatus carrying a heat pump water heater.

  In FIG. 6, 1 is a compressor, 2 is a radiator, 3 is an expansion valve, and 4 is an evaporator, which are configured in an annular shape in this order to form a refrigerant circuit 5. In addition, 6 is an expansion valve inlet pipe, 7 is an expansion valve outlet pipe, 8 is a suction pipe, and 22 is a compressor heat insulating material. Is.

  The operation of the refrigeration cycle apparatus equipped with the heat pump water heater configured as described above will be described below.

  The high-pressure refrigerant discharged from the compressor 1 is supplied to the radiator 2, and heat is exchanged with water in the radiator 2 to dissipate heat and then supplied to the expansion valve 3. After being depressurized by the expansion valve 3, it is supplied to the evaporator 4, absorbs heat, and then sucked into the compressor 1. Moreover, the compressor heat insulating material 22 insulates the compressor 1 and maintains the temperature of the refrigerant supplied to the radiator 2 higher.

  In order to increase the energy efficiency of the refrigeration cycle apparatus, it is necessary to reduce the amount of heat leakage from the compressor 1 so that the compressor 1 is thermally insulated by the compressor heat insulating material 22 (for example, Patent Document 1). reference).

JP 2007-192440 A

  However, in the refrigeration cycle apparatus mounted on the heat pump type water heater described in Patent Document 1, although heat leakage from the high-temperature compressor 1 is suppressed, frost adhering to the evaporator 4 is melted and removed. In the defrosting operation, even though heat transfer from the expansion valve inlet pipe 6 or the expansion valve outlet pipe 7 which becomes high temperature to the low temperature pipe such as the suction pipe 8 occurs, a countermeasure is particularly taken against this. Not. If heat leakage occurs from the expansion valve inlet pipe 6 or the expansion valve outlet pipe 7 during the defrosting operation, the heat energy of the refrigerant supplied to the evaporator 4 is reduced, so that the defrosting operation takes longer and the refrigeration cycle apparatus It had the subject of reducing the energy efficiency of.

  The present invention solves the above-mentioned conventional problems, and operates with high energy efficiency by suppressing heat leakage from the compressor and suppressing heat transfer between refrigerant pipes during defrosting operation. It is an object of the present invention to provide a refrigeration cycle apparatus that can perform such a process.

In order to achieve the above object, a refrigeration cycle apparatus of the present invention includes a compressor, a radiator, a decompression mechanism, a refrigerant circuit formed by sequentially connecting an evaporator that exchanges heat between air and a refrigerant, and the refrigerant circuit. A first refrigerant pipe that supplies a refrigerant from the radiator to the evaporator and a second refrigerant pipe that supplies a refrigerant from the evaporator to the compressor, the compressor A first heat insulating material between the first refrigerant pipe and the second refrigerant pipe, and a second heat insulating material between the first refrigerant pipe and the second refrigerant pipe. Not only suppressing heat leakage, but also suppressing heat transfer from the first refrigerant pipe to the second refrigerant pipe during the defrosting operation, and supplying more heat energy to the evaporator to shorten the defrosting operation. Is possible.

  ADVANTAGE OF THE INVENTION According to this invention, the refrigerating-cycle apparatus which can be drive | operated with high energy efficiency by suppressing the heat leak from a compressor and suppressing the heat transfer between refrigerant | coolant piping at the time of a defrost operation is provided. it can.

Horizontal direction sectional view of the refrigerating cycle device carried in the heat pump water heater in Embodiment 1 of the present invention. Horizontal direction sectional view of the refrigerating cycle device carried in the heat pump water heater in Embodiment 2 of the present invention. Horizontal sectional view of another refrigeration cycle device mounted on the heat pump water heater in Embodiment 2 of the present invention Horizontal sectional view of another refrigeration cycle device mounted on the heat pump water heater in Embodiment 2 of the present invention Horizontal sectional view of a refrigeration cycle system installed in a conventional heat pump water heater Circuit diagram of refrigeration cycle equipment installed in conventional heat pump water heater

  1st invention comprises a refrigerant circuit formed by connecting in order a compressor, a radiator, a decompression mechanism, an evaporator in which air and a refrigerant exchange heat, and a part of the refrigerant circuit to constitute the radiator A first refrigerant pipe for supplying refrigerant from the evaporator to the compressor, and a second refrigerant pipe for supplying refrigerant from the evaporator to the compressor, and between the compressor and the second refrigerant pipe In addition to suppressing heat leakage from the compressor by disposing the second heat insulating material between the first heat insulating material and the first refrigerant piping and the second refrigerant piping, during the defrosting operation The heat transfer from the high-temperature first refrigerant pipe to the low-temperature second refrigerant pipe can be suppressed, and more heat energy can be supplied to the evaporator to shorten the defrosting operation time. The refrigeration cycle apparatus can be operated.

  In the second invention, in particular, the first refrigerant pipe described in the first invention is a refrigerant pipe that supplies the refrigerant from the radiator to the decompression mechanism, so that the decompression mechanism that has a higher temperature during the defrosting operation. The heat transfer from the inlet pipe to the low temperature part can be suppressed, and the defrosting operation time can be shortened compared to the case where the first refrigerant pipe is used as the decompression mechanism outlet pipe.

  In the third invention, in particular, the first refrigerant pipe described in the first invention is a refrigerant pipe that supplies the refrigerant from the decompression mechanism to the evaporator, so that the high-temperature decompression mechanism outlet pipe is used during the defrosting operation. Heat transfer from the low-temperature second refrigerant pipe to the defrosting operation time can be shortened, and during the heating operation, the heat transfer from the medium-temperature second refrigerant pipe to the low-temperature decompression mechanism outlet pipe can be reduced. Therefore, the refrigeration cycle apparatus can be operated with higher energy efficiency than when the first refrigerant pipe is used as the pressure reducing mechanism inlet pipe.

In particular, according to a fourth invention, in any one of the first to third inventions, an average distance L1 between the compressor and the first refrigerant pipe and an average distance L2 between the compressor and the second refrigerant pipe are L1>. By having the relationship of L2, the heat energy leaking from the compressor through the first heat insulating material is received by the second refrigerant pipe during the heating operation, and the degree of superheat of the refrigerant at the evaporator outlet is reduced. The degree of superheat of the refrigerant sucked into the compressor can be increased, and the energy efficiency during the heating operation can be increased as compared with the refrigeration cycle apparatuses according to the first to third inventions.

  According to a fifth aspect of the invention, in particular, in the fourth aspect of the invention, the second heat insulating material is disposed so as to surround the whole or a part of the compressor, so that the high-temperature first refrigerant pipe is used during the defrosting operation. It is possible to reduce the defrosting operation time by suppressing the heat transfer from the first to the low-temperature second refrigerant pipe, and the atmosphere of the space formed in the gap between the first heat insulating material and the second heat insulating material during the heating operation The temperature of the refrigerant flowing through the second refrigerant pipe can be increased by increasing the temperature, and the energy efficiency during the heating operation can be increased as compared with the refrigeration cycle apparatus in the fourth invention.

  In a sixth aspect of the present invention, in particular, in the fourth or fifth aspect of the invention, the second refrigerant pipe is changed from the internal heat exchanger to a part of the suction pipe or a part of the internal heat exchanger, thereby performing the defrosting operation. The heat transfer from the high-temperature first refrigerant pipe to the low-temperature second refrigerant pipe at the time can be suppressed and the defrosting operation time can be shortened, and overheating of the refrigerant sucked into the compressor during the heating operation Since the degree of superheat of the refrigerant at the outlet of the evaporator can be reduced to increase the heat exchange efficiency of the evaporator, the heating operation can be performed more than the refrigeration cycle apparatus in the fourth or fifth invention. The energy efficiency of time can be increased.

  In particular, according to a seventh invention, in any one of the fourth to sixth inventions, the thickness t1, the thermal conductivity k1 of the first heat insulating material, the thickness t2, the thermal conductivity k2 of the second heat insulating material, However, by having a relationship of t1 / k1 <t2 / k2, the heat transfer from the high-temperature first refrigerant pipe to the low-temperature second refrigerant pipe during the defrosting operation is suppressed to shorten the defrosting operation time. In addition, during the heating operation, the atmospheric temperature of the space formed in the gap between the first heat insulating material and the second heat insulating material can be increased, and the degree of superheating of the refrigerant at the evaporator outlet can be reduced. Therefore, the energy efficiency at the time of heating operation can be made higher than that of the refrigeration cycle apparatus in the fourth to sixth inventions.

  In the eighth aspect of the invention, in particular, by using the second heat insulating material described in any one of the first to seventh aspects as a vacuum heat insulating material, the heat insulating material can be thinned, and glass wool, pileton or foaming resin can be used. Effective use of the space around the first and second refrigerant pipes for piping arrangement, etc. while obtaining the effect of improving energy efficiency by heat insulation, compared to the case of using heat insulation with high thermal conductivity of the system can do.

  In the ninth aspect of the invention, when the compressor is driven, the refrigerant circuit is operated at a supercritical pressure so that the heat leakage is suppressed by heat insulation, and the refrigerant does not condense and has a sufficient temperature difference from the fluid to be heated even in a high temperature part. The refrigeration cycle can be operated with high energy efficiency to generate hot water and air.

  In the tenth invention, in particular, by using carbon dioxide as the refrigerant described in the ninth invention, there is no danger of combustion even if the refrigerant leaks, and the refrigeration cycle apparatus can be operated with peace of mind.

  The eleventh aspect of the invention is a heat pump water heater equipped with the refrigeration cycle apparatus according to any one of the first to tenth aspects of the invention.

  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 is a horizontal cross-sectional view of a refrigeration cycle apparatus mounted on a heat pump water heater in a first embodiment of the present invention.

  In FIG. 1, 9 is a first heat insulating material and 10 is a second heat insulating material. The expansion valve inlet pipe 6 and the expansion valve outlet pipe 7 are arranged such that the average distance L1 between the compressor 1 and the average distance L2 between the suction pipe 8 and the compressor 1 is larger.

  Further, as shown in FIG. 1, the first heat insulating material 9 is wound around the compressor 1 and disposed, and the second heat insulating material 10 is a vacuum heat insulating material, which is connected to the expansion valve inlet pipe 6 and the suction pipe. It is disposed in the gap between the pipes 8 or in the gap between the expansion valve outlet pipe 7 and the suction pipe 8. Further, the refrigerant circuit 5 is configured as shown in FIG. 5 similarly to the conventional refrigeration cycle apparatus, and carbon dioxide circulates as a refrigerant in the refrigerant circuit 5.

  About the refrigerating-cycle apparatus comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  When the refrigeration cycle apparatus is in the defrosting operation state, the first heat insulating material 9 suppresses heat leakage from the compressor 1 (about 50 to 100 ° C.) to the surroundings (about 10 to 30 ° C.). Suppresses heat transfer from the expansion valve inlet pipe 6 (about 25 to 50 ° C.) and the expansion valve outlet pipe 7 (about 5 to 15 ° C.) to the suction pipe 8 (about 0 ° C.).

  On the other hand, when the refrigeration cycle apparatus is in the heating operation state, the first heat insulating material 9 is heated from the high-temperature compressor 1 (about 90 to 120 ° C.) to the surroundings (about 10 to 30 ° C.) as in the defrosting operation. Leakage is suppressed, and the second heat insulating material 10 suppresses heat transfer from the suction pipe 8 (about 5 to 15 ° C.) to the expansion valve outlet pipe 7 (about −5 to 7 ° C.) contrary to the defrosting operation. . In addition, the suction pipe 8 (about 5 to 15 ° C.) is disposed closer to the compressor 1 (about 10 to 30 ° C.) than the expansion valve inlet pipe 6 and the expansion valve outlet pipe 7, whereby the first heat insulating material. The thermal energy leaking from the compressor 1 is received via 9 to increase the degree of superheat of the refrigerant.

  Thus, by arrange | positioning the 1st heat insulating material 9 and the 2nd heat insulating material 10, and suppressing a heat leak and heat transfer as mentioned above, in the time of a defrost operation, after being discharged from the compressor 1 The heat energy of the refrigerant supplied to the evaporator 4 is kept large by suppressing the heat radiation from the refrigerant, and the frost adhering to the evaporator 4 is quickly melted and removed, and is supplied to the radiator 2 during the heating operation. In addition to increasing the temperature of the refrigerant to be discharged, the refrigerant acts to increase the degree of superheating of the refrigerant sucked into the compressor 1 while decreasing the degree of superheating of the refrigerant at the outlet of the evaporator 4.

  As described above, in the present embodiment, the suction pipe 8 is disposed closer to the compressor 1 than the expansion valve inlet pipe 6 and the expansion valve outlet pipe 7, and the suction pipe 8 is disposed between the compressor 1 and the suction pipe 8. By disposing the second heat insulating material 10 between the one heat insulating material 9, the expansion valve inlet piping 6, the expansion valve outlet piping 7, and the suction piping 8, the defrosting operation is supplied to the evaporator 4. While maintaining the heat energy of the refrigerant large, the frost adhering to the evaporator 4 is rapidly melted and removed, and during the heating operation, the temperature of the refrigerant supplied to the radiator 2 is increased and the outlet of the evaporator 4 is increased. The refrigerant acts to increase the superheat degree of the refrigerant sucked into the compressor 1 while reducing the superheat degree of the refrigerant.

  As a result, the ratio of the defrosting operation time to the total operation time of the refrigeration cycle apparatus can be reduced, and the heat leakage from the compressor 1 can be suppressed and the heat exchange efficiency of the evaporator can be improved during the heating operation. The refrigeration cycle apparatus can be operated with high energy efficiency.

In the present embodiment, the suction pipe 8 is arranged closer to the compressor 1 than the expansion valve inlet pipe 6 and the expansion valve outlet pipe 7, but the expansion valve inlet pipe 6 and the expansion valve outlet are arranged. Even if the pipe 7 is disposed nearer to the compressor 1 than the suction pipe 8 or similarly, the expansion valve inlet pipe 6 and the expansion valve outlet pipe 7 to the suction pipe 8 during the defrosting operation. Thus, the effect of shortening the defrosting operation time can be obtained.

  In the present embodiment, the second heat insulating material 10 is a vacuum heat insulating material, but glass wool, pileton or foamed resin may be used. The first heat insulating material 9 and the second heat insulating material 10 may both be heat insulating sound absorbing materials integrated with the sound absorbing material.

(Embodiment 2)
FIG. 2 is a horizontal cross-sectional view of the refrigeration cycle apparatus mounted on the heat pump water heater in the second embodiment of the present invention. As shown in FIG. 2, the second heat insulating material 10 is disposed so as to surround the surrounding space of the compressor 1, and is not shown in the drawing, but the second heat insulating material 10 is also arranged above the compressor 1 in the vertical direction. It is installed.

  Further, the refrigerant circuit 5 is configured as shown in FIG. 6 similarly to the conventional refrigeration cycle apparatus and the refrigeration cycle described in (Embodiment 1), and carbon dioxide circulates as a refrigerant in the refrigerant circuit 5.

  About the refrigerating-cycle apparatus comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  Since the operation when the refrigeration cycle apparatus is in the defrosting operation state is the same as that of the refrigeration cycle apparatus described in (Embodiment 1), the details thereof will be omitted, but the second heat insulating material 10 is provided with the expansion valve inlet pipe 6 ( The heat transfer from the expansion valve outlet pipe 7 (about 5 to 15 ° C.) to the suction pipe 8 (about 0 ° C.) is suppressed.

  On the other hand, when the refrigeration cycle apparatus is in the heating operation state, the first heat insulating material 9 is moved from the high-temperature compressor 1 (about 90 to 120 ° C.) to the surroundings (about Although the heat leakage to 20 to 50 ° C. is suppressed, the second heat insulating material 10 transfers heat from the suction pipe 8 (about 5 to 15 ° C.) to the expansion valve outlet pipe 7 (about −5 to 7 ° C.). In addition to suppressing the above, the movement of the air existing in the gap between the first heat insulating material 9 and the second heat insulating material 10 is prevented, and the atmospheric temperature (about 20 to 50 ° C.) of the gap is increased. Yes.

  In addition, the suction pipe 8 is closer to the compressor 1 (about 20 to 50 ° C.) than the expansion valve inlet pipe 6 and the expansion valve outlet pipe 7 as in the refrigeration cycle apparatus described in the first embodiment. By being arranged, more heat energy leaking from the compressor 1 via the first heat insulating material 9 is received, and the degree of superheat of the refrigerant is increased.

  Thus, by arrange | positioning the 1st heat insulating material 9 and the 2nd heat insulating material 10, and suppressing a heat leak and heat transfer as mentioned above, in the time of a defrost operation, after being discharged from the compressor 1 The heat energy of the refrigerant supplied to the evaporator 4 is kept large by suppressing the heat radiation from the refrigerant, and the frost adhering to the evaporator 4 is quickly melted and removed, and is supplied to the radiator 2 during the heating operation. In addition to increasing the temperature of the refrigerant to be discharged, the refrigerant acts to increase the degree of superheating of the refrigerant sucked into the compressor 1 while decreasing the degree of superheating of the refrigerant at the outlet of the evaporator 4.

As described above, in the present embodiment, the suction pipe 8 is disposed closer to the compressor 1 than the expansion valve inlet pipe 6 and the expansion valve outlet pipe 7, and the suction pipe 8 is disposed between the compressor 1 and the suction pipe 8. By disposing the second heat insulating material 10 between the one heat insulating material 9, the expansion valve inlet piping 6, the expansion valve outlet piping 7, and the suction piping 8, the defrosting operation is supplied to the evaporator 4. While maintaining the heat energy of the refrigerant large, the frost adhering to the evaporator 4 is rapidly melted and removed, and during the heating operation, the temperature of the refrigerant supplied to the radiator 2 is increased and the outlet of the evaporator 4 is increased. The refrigerant acts to increase the superheat degree of the refrigerant sucked into the compressor 1 while reducing the superheat degree of the refrigerant.

  As a result, the ratio of the defrosting operation time to the total operation time of the refrigeration cycle apparatus can be reduced, and the heat leakage from the compressor 1 can be suppressed and the heat exchange efficiency of the evaporator can be improved during the heating operation. The refrigeration cycle apparatus can be operated with high energy efficiency.

  In addition, the suction pipe 8 of this Embodiment may be the internal heat exchanger 21 arrange | positioned as shown in FIG.

  In general, during the heating operation, the temperature of the high-pressure side refrigerant that exchanges heat with the low-pressure side refrigerant in the internal heat exchanger 21 (about 5 to 30 ° C.) is the gap between the first heat insulating material 9 and the second heat insulating material 10. Lower than ambient temperature (about 20-50 ° C.).

  By doing in this way, at the time of defrosting operation, the heat energy of the refrigerant | coolant supplied to the evaporator 4 is largely maintained by suppressing the heat radiation from the refrigerant | coolant discharged from the compressor 1, and the evaporator 4 is maintained. In addition to acting to quickly melt and remove frost adhering to the refrigerant, the refrigerant supplied to the compressor 1 from the outlet of the evaporator 4 is high-pressure in the internal heat exchanger 21 particularly during heating operation. The refrigerant receives heat from the side refrigerant, receives heat from the atmosphere in the gap between the first heat insulating material 9 and the second heat insulating material 10 in the downstream or in the low pressure side refrigerant piping of the internal heat exchanger 21, and flows the refrigerant at the outlet of the evaporator 4. The refrigeration cycle apparatus can be operated with high energy efficiency by acting to increase the superheat degree of the refrigerant sucked into the compressor 1 while reducing the superheat degree.

  Moreover, the 1st heat insulating material 9 and the 2nd heat insulating material 10 of this Embodiment have a relationship of t1 / k1 <t2 / k2, and may be arrange | positioned as shown in FIG.

  During the defrosting operation, heat release from the refrigerant discharged from the compressor 1 is suppressed, and the heat energy of the refrigerant supplied to the evaporator 4 is kept large, and the frost attached to the evaporator 4 is melted quickly. In addition to acting so as to be removed, in particular, during the heating operation, the atmospheric temperature (about 35 to 70 ° C.) of the gap between the first heat insulating material 9 and the second heat insulating material 10 is increased to perform suction. While the pipe 8 increases the amount of heat energy received from the atmosphere and reduces the degree of superheat of the refrigerant at the outlet of the evaporator 4, it acts to effectively suppress the heat leakage from the compressor 1. The refrigeration cycle apparatus can be operated with high energy efficiency.

  As described above, the refrigeration cycle apparatus according to the present invention can suppress heat leakage and heat transfer from a high-temperature part such as a compressor during heating operation, and can use the evaporator with high heat exchange efficiency. At the same time, the defrosting operation time can be shortened during the defrosting operation, and the refrigeration cycle apparatus can be operated with high energy efficiency. Therefore, the refrigeration using the heat radiation side, such as a heat pump water heater or a hot water heater. It can also be applied to improve the energy efficiency of cycle equipment.

DESCRIPTION OF SYMBOLS 1 Compressor 2 Radiator 3 Expansion valve 4 Evaporator 5 Refrigerant circuit 6 Expansion valve inlet piping 7 Expansion valve outlet piping 8 Suction piping 9 1st heat insulating material 10 2nd heat insulating material 21 Internal heat exchanger

Claims (11)

A compressor, a radiator, a decompression mechanism, a refrigerant circuit formed by sequentially connecting an evaporator that exchanges heat between air and a refrigerant, and a part of the refrigerant circuit to form the refrigerant to the evaporator A first refrigerant pipe for supplying refrigerant; and a second refrigerant pipe for supplying refrigerant from the evaporator to the compressor; a first heat insulating material between the compressor and the second refrigerant pipe; A refrigeration cycle apparatus, wherein a second heat insulating material is disposed between a first refrigerant pipe and the second refrigerant pipe. The refrigeration cycle apparatus according to claim 1, wherein the first refrigerant pipe is a refrigerant pipe that supplies a refrigerant from the radiator to the decompression mechanism. The refrigeration cycle apparatus according to claim 1, wherein the first refrigerant pipe is a refrigerant pipe that supplies a refrigerant from the pressure reducing mechanism to the evaporator. The average distance L1 between the compressor and the first refrigerant pipe and the average distance L2 between the compressor and the second refrigerant pipe have a relationship of L1> L2. The refrigeration cycle apparatus according to any one of the above. The refrigeration cycle apparatus according to claim 4, wherein the second heat insulating material surrounds the whole or a part of the compressor. The high-pressure side refrigerant and the low-pressure side refrigerant exchange heat in the refrigerant circuit, and the refrigerant supplied from the evaporator to the compressor includes an internal heat exchanger that exchanges heat with the high-pressure side refrigerant. The second refrigerant pipe is a part of a low-pressure side pipe of the internal heat exchanger or a refrigerant pipe for supplying a refrigerant from the internal heat exchanger to the compressor. 5. The refrigeration cycle apparatus according to 5. The thickness t1, the thermal conductivity k1 of the first heat insulating material and the thickness t2, the thermal conductivity k2 of the second heat insulating material have a relationship of t1 / k1 <t2 / k2. The refrigeration cycle apparatus according to any one of 4 to 6. The refrigeration cycle apparatus according to any one of claims 1 to 7, wherein the second heat insulating material is a vacuum heat insulating material. The refrigeration cycle apparatus according to any one of claims 1 to 8, wherein when the compressor is driven, the refrigerant circuit is operated at a supercritical pressure. The refrigeration cycle apparatus according to claim 9, wherein carbon dioxide is used as the refrigerant. A heat pump water heater equipped with the refrigeration cycle apparatus according to any one of claims 1 to 10.

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