JP2005083692A - Heat pump water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance convenience of a user, without stopping an inverter, even when the outside air temperature is high in summer, by enhancing cooling efficiency of the inverter. <P>SOLUTION: This heat pump water heater has a coolant circuit 10 including a capacity variable compressor 1, a hot water supply heat exchanger 12, a decompressing means 3, and an endothermic unit 4, a coolant pipe 14 and a water pipe 13 for mutually exchanging heat in the hot water supply heat exchanger 12. The heat pump water heater has a water supply pipe 31 for supplying city water to the water pipe 13, a hot water supply terminal 15 for feeding water from the water pipe 13, and the inverter 8 for varying a rotating speed of the compressor 1. The heat pump water heater is characterized by cooling the inverter 8 by the endothermic unit 4. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a heat pump water heater controlled by an inverter, and relates to cooling of the inverter.

  FIG. 7 shows cooling of a conventional inverter. In FIG. 7, the refrigerant circuit 10 to which the compressor 1, the radiator 2, the decompression means 3, and the heat absorber 4 are connected, the inverter 8 to which the radiator plate 9 is attached, the radiator 2, the radiator fan 7 and the radiator plate. It was comprised by the case 6 for radiators which installed 9 and formed an air path. Reference numeral 5 denotes a heat absorber blower.

  Only characteristic operations will be described here. The high-temperature and high-pressure refrigerant discharged from the compressor 1 enters the radiator 2. The refrigerant that has entered the radiator 2 radiates heat by exchanging heat with the outside air introduced into the radiator case 6 by the radiating fan 7.

  That is, the air flow in the radiator case 6 absorbs the heat of the radiator 2 through the radiator 2, reaches the radiator plate 9 attached to the inverter 8, and releases to the outside through the radiator fan 7. Is done.

Moreover, when the temperature of the inverter 8 becomes equal to or higher than the set value, an air conditioner has been proposed in which the operation of the heat dissipating blower 7 is continued and the operation of the inverter 8 is stopped (see, for example, Patent Document 1).
JP-A-60-120128 (FIG. 7)

  However, in the above conventional configuration, since the outside air is heated by the radiator, heat exchange is performed between the air that has become higher than the temperature of the outside air and the heat radiating plate, so that the cooling efficiency of the inverter by the heat radiating plate is poor.

  In particular, when the outside air temperature is high, such as in summer, the cooling efficiency is further reduced, so the inverter temperature may exceed the allowable value. To protect the inverter, the inverter operation is stopped, that is, the compressor is stopped. There is a problem that the convenience for the user is bad.

  An object of the present invention is to increase the cooling efficiency of an inverter and improve the convenience for the user without stopping the inverter even when the outside air temperature is high such as in summer.

  In order to achieve this object, the heat pump water heater of the present invention includes a refrigerant circuit including a variable capacity compressor, a hot water heat exchanger, a decompression means, and a heat absorber, and heat exchange with each other in the hot water heat exchanger. A water supply pipe for supplying city water to the water pipe, a hot water supply terminal for passing water from the water pipe, and an inverter for changing the rotation speed of the compressor And the inverter is cooled by the heat absorber.

  Thus, by using a heat absorber that is lower than the outside air temperature to absorb the heat generated by the inverter, the cooling efficiency of the inverter can be increased even when the outside air temperature is high such as in summer.

  ADVANTAGE OF THE INVENTION According to this invention, the cooling efficiency of an inverter can be improved and a user's convenience can be improved, without stopping an inverter, even when outside temperature is high, such as summer.

  A first invention is a refrigerant circuit including a variable capacity compressor, a hot water supply heat exchanger, a decompression means, and a heat absorber, and a refrigerant pipe and a water pipe that exchange heat with each other in the hot water heat exchanger. A water supply pipe that supplies city water to the water pipe, a hot water supply terminal that passes water from the water pipe, and an inverter that changes the number of revolutions of the compressor. The inverter is cooled.

  This makes it possible to increase the cooling efficiency of the inverter even when the outside air temperature is high, such as in summer, by absorbing the heat generated by the inverter using a heat absorber that is cooler than the outside air temperature, without stopping the inverter. , User convenience can be improved.

  2nd invention is 1st invention, The heat absorber is equipped with the heat sink fan apparatus for accelerating | sucking the heat | fever absorption from air | atmosphere, and the heat sink which is attached to an inverter and accelerates | stimulates heat radiation, A heat radiating plate was installed in the air passage blown by the blower.

  As a result, the heat absorbed by the heat sink and the heat of the heat sink can be absorbed by the air that has become lower than the outside air temperature, so the cooling efficiency of the heat sink can be increased and the cooling efficiency of the inverter can be increased. The convenience of the user can be improved without stopping.

  3rd invention is 2nd invention, and installed the heat sink in parallel with the flow of the wind in an air path.

  As a result, the outside air flows between the heat sinks, the outside air uniformly contacts the heat sinks and can dissipate heat, and the heat dissipation efficiency at the heat sinks can be further increased, so that the convenience of the user can be improved without stopping the inverter. Can be increased.

  A fourth invention is the invention according to claim 2 or 3, wherein the predetermined blown amount of the heat absorber blower is set as the minimum blown amount.

  This makes it possible to absorb the heat of the heat sink by the air absorbed by the heat absorber and become cooler than the outside air temperature, increase the cooling efficiency of the heat sink, increase the cooling efficiency of the inverter, and stop the inverter In addition, user convenience can be improved. In addition, energy efficiency can be improved while avoiding shortage of heat radiation by the heat sink.

  A fifth invention is the second to fourth inventions, wherein a part of the heat radiating plate is brought into contact with the heat absorber to conduct heat.

  As a result, in addition to heat absorption by the outside air, heat can be radiated to the heat absorber by heat conduction, so that the cooling efficiency of the heat sink can be increased and the cooling efficiency of the inverter can be further increased, so the inverter is stopped. Therefore, the convenience for the user can be improved.

  A sixth invention is the first to fifth inventions, each having a plurality of compressors, a heat absorber blower, an inverter, and a heat radiating plate.

  As a result, the heat of each heat sink can be absorbed by the air that has been absorbed by each heat sink and becomes lower than the outside air temperature, so that the cooling efficiency of each heat sink can be increased, and the cooling efficiency of each inverter can be increased. Therefore, the convenience of the user can be improved without stopping the inverter.

  A seventh invention is the sixth invention, wherein a plurality of the refrigerant circuits are provided at a position where a pair of the heat absorber blower installed in the same air passage of the plurality of refrigerant circuits and the heat sink of the inverter are paired. The heat-absorbing device blower, which is paired when a part of the air-conditioner stops, is set to a predetermined blowing amount.

  As a result, the heat of each heat sink can be absorbed by the air that has been absorbed by the heat sink and becomes lower than the outside air temperature, so that the cooling efficiency of each heat sink can be increased, and the cooling efficiency of each inverter can be increased. Therefore, user convenience can be improved without stopping the inverter. In addition, energy efficiency can be improved while avoiding shortage of heat radiation by each heat sink.

  The eighth invention is the sixth invention, wherein the heat absorber blower and the inverter heat sink are installed in a pair of independent air passages, and the heat sink blower paired when a part of the refrigerant circuit stops. The device was stopped.

  As a result, the heat of each heat sink can be absorbed by the air that has been absorbed by each heat sink and becomes lower than the outside air temperature, and the cooling efficiency of each heat sink can be increased. The convenience of the user can be enhanced without stopping the inverter. In addition, energy efficiency can be further improved while avoiding shortage of heat radiation by each heat sink.

  According to a ninth invention, in the inventions described in the first to eighth inventions, a refrigerant whose pressure is equal to or higher than a critical pressure is used in the refrigerant circuit.

  According to the present invention, since the refrigerant flowing through the hot water supply heat exchanger is pressurized to a critical pressure or higher by the compressor, the refrigerant is condensed even if the temperature is lowered due to heat deprived by the flowing water in the water flow path of the heat exchanger. There is nothing to do. Therefore, it becomes easy to form a temperature difference between the refrigerant and water in the entire heat exchanger, high-temperature hot water can be obtained, and heat exchange efficiency can be increased.

  Embodiments of a heat pump water heater according to the present invention will be described below with reference to the drawings.

(Example 1)
Hereinafter, a heat pump water heater according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a circuit configuration diagram of a heat pump water heater in Embodiment 1 of the present invention.

  First, the heat pump circuit of the heat pump water heater according to the present embodiment will be described. The refrigerant circuit 10 is configured by connecting a compressor 1, a hot water supply heat exchanger 12, a decompression unit 3, and a heat absorber 4 in order, and a blower for a radiator for introducing outside air into the heat absorber 4. 5 and an air passage 11 are provided. In addition, a heat radiating plate 9 for cooling the inverter 8 is installed in the air passage 11.

  The heat pump water heater according to this embodiment preferably uses carbon dioxide as a refrigerant and is operated in a state where the critical pressure is exceeded on the high pressure side.

  Next, the hot water supply circuit 19 of the heat pump water heater according to the present embodiment will be described. The hot water supply circuit 19 is connected to the water supply pipe 31 such as a water pipe via the pressure reducing valve 16 on the inflow side of the water pipe 13, and is connected to the kitchen or the washroom via the water pipe 13 of the hot water supply heat exchanger 12. Is connected to a hot water supply terminal 15 such as a hot water supply faucet.

  The hot water circuit 19 includes a flow rate sensor 30 </ b> A for detecting the amount of incoming water flowing into the water pipe 13 and a temperature sensor 30 </ b> B for detecting the outlet temperature of the water pipe 13. Further, the heat absorber 4, the heat absorber blower 5, the inverter 8, the heat radiating plate 9 and the air passage 11 form a heat absorber 20. Reference numeral 17 denotes a remote controller that allows the user to set a desired hot water supply temperature, and 18 denotes a control device.

  Hereinafter, the hot water supply operation of the heat pump water heater according to the present embodiment will be described. When the opening of the hot water supply terminal 15 is detected by the flow sensor 30A and water flows out of the hot water circuit 19, the refrigerant circuit 10 starts operation. That is, the control device 18 sends a command to the inverter 8 to start the compressor 1. At this time, the electronic components incorporated in the inverter 8 generate heat and gradually rise in temperature.

  In the refrigerant circuit 10, the refrigerant is compressed by the compressor 1 and is in a high-pressure and high-temperature gas state. The refrigerant pipe 14 in the hot water supply heat exchanger 12 exchanges heat with water flowing in the water pipe 13 to release heat. descend. Further, the pressure is reduced by the pressure reducing means 3, the pressure is lowered, and a two-phase state of a low-temperature liquid and gas is obtained. Then, the heat absorber 4 absorbs heat and is sucked into the compressor 1 in a gas state.

  In the heat absorber 4, the temperature of the refrigerant flowing inside becomes lower than the outside air temperature, so that heat is exchanged with the outside air introduced into the air passage 11 by the heat absorber blower 5 to absorb heat from the outside air. At this time, the temperature of the outside air subjected to heat exchange decreases. Further, heat exchange is performed by contacting the outside air whose temperature has decreased and the heat radiating plate 9 which has become high temperature by conducting heat generated by the inverter 8. That is, the heat of the inverter 8 is guided to the heat radiating plate 9 by heat conduction, and the heat of the heat radiating plate 9 is absorbed by the outside air, so that the inverter 8 is cooled.

  On the other hand, the water supplied from the water supply pipe 31 passes through the pressure reducing valve 16 and is guided to the water pipe 13 of the hot water supply heat exchanger 12. Hot water heated by exchanging heat with the refrigerant flowing in the refrigerant pipe 14 in the water pipe 13 in the hot water supply heat exchanger 12 is guided to the water supply terminal 15.

  The hot water supply capacity control in the compressor 1, the air volume control of the heat absorber blower 5, and the opening degree control in the pressure reducing means 3 are performed so that the temperature detected by the temperature sensor 30 </ b> B approaches the hot water temperature set by the remote controller 17. This is performed based on detection values from the sensor 30A and the temperature sensor 30B. That is, the excess / deficiency of the capacity is calculated by multiplying the difference between the hot water temperature set by the remote controller 17 and the hot water temperature detected by the hot water temperature sensor 30B by the flow rate of water detected by the flow sensor 30A.

  When the controller 18 determines that the capacity is insufficient, the inverter 8 increases the rotational speed of the compressor 1 by a predetermined value, and the decompression means 3 also increases the predetermined value opening degree. The air volume of the heat absorber blower 5 does not change.

  When the controller 18 determines that the capacity is excessive, the inverter 8 reduces the rotational speed of the compressor 1 by a predetermined value, and the decompression means 3 also decreases the predetermined value opening degree. The air volume of the heat absorber blower 5 does not change.

  Further, when the capacity is excessive and the rotation speed of the compressor 1 reaches the minimum rotation speed, the air volume of the heat absorber blower 5 is decreased by a predetermined value.

  FIG. 2 is a perspective view showing a configuration of the heat absorbing device 20 in FIG. In the present embodiment, the inverter 8 and the heat radiating plate 9 are installed on the top surface of the heat absorbing device 20, and are arranged in parallel to the flow of the outside air so that the outside air uniformly contacts the heat radiating plate 9. Thereby, since the contact area of the heat sink 9 and external air can be enlarged, the heat sink 9 heat dissipation efficiency can be improved.

  FIG. 3 is a graph showing an example of the relationship between the number of rotations of the compressor 1 and the blower amount of the heat absorber blower 5 in FIG. When the compressor 1 is larger than the minimum rotation speed Rmin, the air volume of the heat absorber blower 5 is constant at Qn, and when the compressor 1 reaches the minimum rotation speed Rmin and the capacity is controlled to reduce the hot water supply capacity. The control is performed in a range Qn to Qmin that does not fall below the predetermined minimum air volume.

  As a result, the necessary heat dissipation amount of the inverter 8 is ensured, so that an abnormal temperature rise of the inverter 8 can be avoided and the power consumption of the heat absorber blower 5 can be reduced by reducing the amount of air blown by the heat absorber blower 5. This can improve energy efficiency.

  FIG. 4 is a conceptual diagram showing the relationship between the heat sink 9 and the heat absorber 4 in FIG. In FIG. 4, only the heat sink 9 and the heat absorber 4 are shown, and the others are omitted. In FIG. 4, a part of the heat radiating plate 9 is embedded in the heat absorber 4 and brought into contact therewith. Thereby, the heat of the heat radiating plate 9 is absorbed by the heat absorber 4 by heat conduction and the inverter 8 is cooled, so that the cooling efficiency is further improved.

  In the present embodiment, the refrigerant is described as carbon dioxide, but a natural refrigerant such as ammonia, a fluorocarbon refrigerant such as R410A, or a hydrocarbon refrigerant (HC refrigerant) such as propane or butane may be used.

  Moreover, although the present Example demonstrated as an instantaneous type heat pump water heater which discharges hot water directly to the hot water supply terminal 15 using a heat pump, you may use the hot water storage type heat pump water heater which stores hot water in a hot water storage tank using a heat pump. .

(Example 2)
FIG. 5 is a circuit configuration diagram of a heat pump water heater according to another embodiment 2 of the present invention. In the present embodiment, in order to simplify the description, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  First, the heat pump circuit of the heat pump water heater according to the present embodiment will be described. The other refrigerant circuit 10A is configured by connecting a compressor 1A, a hot water supply heat exchanger 2A, a decompression means 3A, and an evaporator 4A in order by a pipe, and a blower for a heat absorber for blowing air to the heat absorber 4A. 5A and the air path 11 are provided. Further, a radiator plate 9A for cooling the inverter 8A is installed in the air passage 11.

  The heat pump water heater according to this embodiment preferably uses carbon dioxide as a refrigerant and is operated in a state where the critical pressure is exceeded on the high pressure side.

  Next, the hot water supply circuit 19 of the heat pump water heater according to the present embodiment will be described. The inflow side of the water pipe 13A is connected to a water supply pipe 31 such as a water pipe through the pressure reducing valve 16 and the flow meter 30A in parallel with the water pipe 13. Further, the outflow side of the water pipe 13A is connected in parallel to the water pipe 13 to a hot water supply terminal 15 such as a kitchen or a faucet for hot water supply such as a washroom. Further, the heat absorbers 4, 4 </ b> A, the heat absorber blowers 5, 5 </ b> A, and the heat sinks 9, 9 </ b> A are housed in the same air passage 11 to form the heat absorber 20.

  The inverter 8 and the radiator plate 9 that drive the compressor 1 are installed in the vicinity of the heat absorber blower 5, and the inverter 8A and the radiator plate 9 A that drive the compressor 1 A are installed in the vicinity of the heat absorber fan 5 A. Has been.

  Hereinafter, the hot water supply operation of the heat pump water heater according to the present embodiment will be described. When the opening of the hot water supply terminal 15 is detected by the flow sensor 30A and water flows through the hot water circuit 19, the refrigerant circuits 10 and 10A start operation. That is, the control device 18 sends a command to the inverters 8 and 8A to start the respective compressors 1 and 1A. At this time, the electronic components incorporated in the inverters 8 and 8A generate heat and gradually rise in temperature.

  In the refrigerant circuit 10A, the refrigerant is compressed by the compressor 1A and is in a high-pressure and high-temperature gas state. The refrigerant pipe 14A in the hot water supply heat exchanger 12A exchanges heat with water flowing in the water pipe 13A, and is radiated and radiated. Decreases. Further, the pressure is reduced by the pressure reducing means 3A, the pressure is lowered, and a two-phase state of a low-temperature liquid and gas is obtained. Then, the heat is absorbed by the heat absorber 4A and is sucked into the compressor 1A in a gas state. In the heat absorber 4, heat is exchanged with the outside air introduced into the air path 11 by the heat absorber blower 5 </ b> A to absorb heat from the outside air, and the temperature of the heat exchanged outside air is lowered.

  Further, the outside air whose temperature has passed through the air passage 11 is brought into contact with the heat sink 9A to absorb heat. The heat of the inverter 8A is guided to the heat sink 9A by heat conduction. That is, since the heat of the inverter 8A is absorbed by the outside air, the inverter 8A is cooled.

  On the other hand, the water supplied from the water supply pipe 31 passes through the pressure reducing valve 16 and is guided to the water pipe 13A of the hot water supply heat exchanger 12A. Hot water heated by exchanging heat with the refrigerant flowing in the refrigerant pipe 14 </ b> A in the water pipe 13 </ b> A in the hot water supply heat exchanger 12 </ b> A is guided to the water supply terminal 15.

  The capacity control in the compressor 1A, the air volume control of the heat absorber blower 5A, and the opening degree control in the pressure reducing means 3A are performed so that the temperature detected by the temperature sensor 30B approaches the hot water temperature set by the remote controller 17. It is controlled by the detection value from 30A and temperature sensor 30B. That is, the excess / deficiency of the capacity is calculated by multiplying the difference between the hot water temperature set by the remote controller 17 and the hot water temperature detected by the hot water temperature sensor 30B by the flow rate of water detected by the flow sensor 30A.

  When the controller 18 determines that the capacity is insufficient, the inverter 8A increases the rotational speed of the compressor 1A by a predetermined value, and the decompression means 3A also increases the predetermined value opening.

  The air volume of the heat absorber blower 5A does not change. When the controller 18 determines that the capacity is excessive, the inverter 8A reduces the rotational speed of the compressor 1A by a predetermined value, and the decompression means 3A also decreases the predetermined value opening degree.

  The air volume of the heat absorber blower 5A does not change. Furthermore, if the capacity is excessive and the compressor 1A is stopped, the air volume of the heat absorber blower 5A is reduced to a predetermined value and set.

  Thereby, since the heat of the heat sinks 9 and 9A can be absorbed by the outside air absorbed by the heat absorbers 4 and 4A, the cooling efficiency of the heat sinks 9 and 9A can be increased, and the inverters 8 and 8A can be increased. The cooling efficiency can be increased.

  Moreover, energy efficiency can be improved by suppressing the power consumption by reducing the air volume of the air blower 5A for the heat absorber on the stop side while avoiding the shortage of the heat radiation amount by each heat sink.

  In the present embodiment, the refrigerant circuits 10 and 10A are described as two circuits, but three or more circuits may be used. Further, although the refrigerant is described as carbon dioxide, a natural refrigerant such as ammonia, a fluorocarbon refrigerant such as R410A, or a hydrocarbon refrigerant (HC refrigerant) such as propane or butane may be used. Different refrigerants may be used for each circuit.

(Example 3)
FIG. 6 is a circuit configuration diagram of a heat pump water heater according to another embodiment 3 of the present invention. In the present embodiment, in order to simplify the description, the same components as those in the first and second embodiments are denoted by the same reference numerals, and detailed description thereof is omitted.

  Reference numeral 19 denotes a partition plate. The heat absorber 4 </ b> A, the heat absorber blower 5 </ b> A, and the heat radiating plate 9 </ b> A are installed in the air passage 11 </ b> A partitioned by the partition plate 19, and the heat absorber 4, the heat absorber blower 5, and the heat radiating plate 9 are housed in the air passage 11. . When the controller 18 determines that the capacity is excessive and the compressor 1A is stopped, the heat absorber blower 5A is stopped. According to this, energy efficiency can be further improved by stopping the heat sink blower device 5A on the stop side and suppressing power consumption while avoiding shortage of heat radiation by each heat sink.

  In the present embodiment, the refrigerant circuits 10 and 10A are described as two circuits, but three or more circuits may be used. Further, although the refrigerant is described as carbon dioxide, a natural refrigerant such as ammonia, a fluorocarbon refrigerant such as R410A, or a hydrocarbon refrigerant (HC refrigerant) such as propane or butane may be used. Furthermore, a different refrigerant may be used for each circuit.

  As described above, the heat pump water heater according to the present invention increases the cooling efficiency of the inverter, and even when the outside air temperature is high such as in summer, the convenience of the user can be improved without stopping the inverter. There is a possibility to use on.

FIG. 1 is a circuit configuration diagram of Embodiment 1 of a heat pump water heater according to the present invention. The principal part perspective view in Example 1 of the heat pump water heater by this invention Characteristics diagram of compressor rotation speed and air volume of heat pump water heater according to the present invention The conceptual diagram which shows the structure of the heat sink and heat sink of the heat pump water heater by this invention FIG. 3 is a circuit configuration diagram of Embodiment 2 of a heat pump water heater according to the present invention. Circuit configuration diagram of Embodiment 3 of the heat pump water heater according to the present invention Conventional circuit diagram

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compressor 3 Pressure reducing means 4 Heat absorber 5 Heat blower for heat absorber 8 Inverter 9 Heat sink 10 Refrigerant circuit 12 Heat exchanger for hot water supply 13 Water pipe 14 Refrigerant pipe 15 Water supply terminal 31 Water supply pipe

Claims (9)

A refrigerant circuit including a variable capacity compressor, a hot water supply heat exchanger, a decompression unit, and a heat absorber; a refrigerant pipe and a water pipe that exchange heat with each other in the hot water heat exchanger; A water supply pipe that supplies city water to the pipe, a hot water supply terminal that passes water from the water pipe, and an inverter that varies the number of revolutions of the compressor, and the inverter is cooled by the heat absorber. A heat pump hot water supply machine. A heat absorber is provided with a heat absorber blower for promoting the absorption of heat from the atmosphere, and a heat radiating plate attached to the inverter for promoting heat dissipation, and in the air passage blown by the heat absorber blower The heat pump water heater of Claim 1 which installed the said heat sink. The heat pump water heater according to claim 2, wherein the heat radiating plate is installed in parallel with the air flow in the air passage. The heat pump water heater according to claim 2 or 3, wherein the blower amount for the heat absorber is set to a minimum blower amount. The heat pump water heater according to claim 2, wherein a part of the heat radiating plate is brought into thermal contact with the heat absorber. The heat pump water heater according to any one of claims 1 to 5, wherein a plurality of compressors, heat-absorber blowers, inverters, and heat sinks are provided, and a plurality of refrigerant circuits are configured by these. The heat absorption device that is paired when a part of the plurality of refrigerant circuits is stopped, provided in a position where the heat sink of each heat absorber installed in the same air passage of the plurality of refrigerant circuits and the radiator heat sink are paired. The heat pump water heater according to claim 6, wherein the blower device is set to a predetermined minimum air flow rate. 7. The heat absorber blower and the inverter heat sink are installed in a pair of independent air passages, and when the refrigerant circuit is partially stopped, the pair of heat absorber blowers is stopped. The heat pump water heater described. The refrigerant circuit is a supercritical heat pump cycle in which the pressure of the refrigerant is equal to or higher than the critical pressure, and the flowing water in the water flow path of the heat exchanger is heated by the refrigerant whose pressure is increased to the critical pressure or higher. 8. The heat pump water heater according to any one of 8 items.

Images