JP4016875B2 - Heat pump water heater - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat pump water heater.
[0002]
[Prior art]
As shown in FIG. 2, the conventional heat pump hot water supply apparatus is configured by connecting a compressor 2, a heat exchanger 3 as a radiator, a decompression means 4, and a heat absorber 5 through a refrigerant pipe 1 configured in a closed circuit. A refrigerant circulation circuit 6, a water flow path 8 in the heat exchanger 3 that exchanges heat with the refrigerant flow path 7 of the heat exchanger 3, a water supply pipe 9 that supplies tap water to the water flow path 8, and the water flow path 8 And a hot water supply circuit 11 for connecting a hot water supply terminal 10 such as a shower and a faucet, a temperature sensor 12 provided in the hot water supply circuit 11 for detecting the hot water supply temperature, and an inverter 13 for controlling the rotation speed of the compressor 2, There is one in which the hot water supply set temperature set by the means 14 and the compressor 2 convert the output frequency of the inverter 13 by the control means 15 according to the difference between the temperature detected by the temperature sensor 12 (for example, Patent Document 1). reference.). That is, in the conventional hot water supply device, the heating speed is changed according to the hot water supply load by controlling to increase the rotation speed of the compressor 2 when the hot water supply temperature is lower than the set temperature and lowering the rotation speed when the hot water supply temperature is high. Let
[0003]
Conventionally, in a multi-type air conditioner, a plurality of compressors are connected in parallel, and one of the compressors has a variable capacity and the other compressor has a constant capacity. By changing the number of compressors with constant capacity to be operated and the operating capacity of variable capacity compressors, a compression capacity corresponding to a wide range of load fluctuations has been realized.
[0004]
[Patent Document 1]
JP-A-2-223767
[Problems to be solved by the invention]
However, in the configuration of the conventional heat pump hot water supply apparatus, the hot water supply load during hot water supply is not constant. In particular, since the flow rate is varied by the user depending on the purpose of hot water supply, the hot water supply load changes greatly. For example, in the case of hot water supply for home use, a large flow rate of 10 to 20 L / min is used when supplying hot water to a shower or bath, but 3 to 5 L / min for washing dishes in the kitchen or hot water supply to the wash surface. Small flow rate. In addition, the hot water supply load varies greatly depending on the seasonal change in the temperature of the water supply.
[0006]
When a hot water supply load that varies greatly depending on changes in the flow rate and water temperature is to control the amount of hot water supply by simply changing the rotation speed of a single compressor as in the conventional heat pump water heater, A large compressor is required to cope with the hot water supply load. However, there is a limit in reducing the capacity for a small hot water supply load, and there is a disadvantage that it is difficult to cope with such a low load.
[0007]
In this way, with the conventional heat pump hot water supply device, there is a limit to the capacity change width in the control that only changes the rotation speed of a single compressor with a large device, for example, large capacity such as simultaneous use of shower and bath hot water filling , And could not cover a wide range of hot water supply capacity, from dishwashing and other micro-capacities. For this reason, there may be inconveniences such as a drop in shower temperature and hot water coming out of the dishes.
[0008]
Also, if the operating conditions of the heat pump cycle change due to temperature, water temperature, and hot water supply load, the operating efficiency also changes, but the conventional heat pump water heater only changes the rotation speed of the large compressor according to the hot water supply temperature, so the temperature Not only the start-up is delayed, but even when the hot water supply load is small, the large compressor is operated under the condition that the mechanical loss is large and the operation efficiency is poor. Therefore, depending on the conditions, the efficiency is extremely deteriorated and not only the ability cannot be exhibited, but also the running cost may be increased.
[0009]
As described above, the conventional heat pump water heater is operated with a single compressor regardless of the size of the hot water supply load and the outside air condition, so it is difficult to cope with a wide range of hot water supply loads, the responsiveness deteriorates, There were problems such as deterioration of efficiency.
[0010]
Also, in the conventional multi-type air conditioner, the compression capacity is widely changed by configuring one compressor with variable capacity and the other compressor with constant capacity, and greatly varies depending on the number of indoor units operated. It corresponds to the air conditioning load. When changing the compression capacity in accordance with the change in the load, the number of compressors having a constant capacity is changed, and at the same time, the operating capacity of the variable capacity compressor is changed, so that the change in the compression capacity is delayed. The use of hot water at the hot water supply terminal is mostly for a short time of a few seconds to a few minutes, and the overall hot water supply load changes abruptly depending on the number of hot water terminals used and their flow rates. Even if the product is applied to a hot water supply device, it cannot cope with a sudden change in hot water supply load. In addition, since the variable capacity compressor is continuously operated, there is a problem that the life is shortened compared with other compressors having a constant volume, and the reliability of the apparatus is lowered.
[0011]
SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and provides a heat pump hot water supply apparatus that can quickly cope with a wide range of fluctuations in hot water supply load and that improves the reliability of the apparatus by dispersing the burden on the compressor. The purpose is to provide.
[0012]
[Means for Solving the Problems]
In order to solve the above problems, the present invention performs a heat exchange with a refrigerant circulation circuit including a plurality of compressors connected in parallel and a hot water supply heat exchanger as a radiator, and a refrigerant flow path of the hot water supply heat exchanger. A water flow path in the hot water supply heat exchanger to be performed, a water supply pipe for supplying tap water to the water flow path, a hot water supply circuit connected to pass water from the water flow path to the hot water supply terminal, and the hot water supply heat exchanger A boiling temperature detection means for detecting the water temperature at the outlet, a hot water temperature setting means for setting the hot water temperature, and a hot water heat exchanger are provided in parallel with the hot water supply circuit via the mixing means. A hot water storage tank for storing hot water that is hotter than the hot water supply temperature , wherein the plurality of compressors are variable in operating frequency, and when the detected temperature of the boiling temperature detecting means is equal to or lower than a predetermined value, the hot water supply heat exchange Before the water from the vessel and the water from the hot water storage tank Is obtained by the heat pump hot water supply apparatus is characterized in that a configuration of mixing in the mixing unit.
[0013]
According to the above invention, since the plurality of compressors are connected in parallel, the compression capacity can be widely changed from the operation at the minimum capacity of one compressor to the operation at the maximum capacity of all the compressors. . Since the operation frequency of the compressor is variable, the compressor can be operated with as many compressors as possible and can be quickly changed to the required compression capacity.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
The heat pump hot water supply apparatus according to the first aspect of the present invention includes a refrigerant circulation circuit including a plurality of compressors connected in parallel and a hot water supply heat exchanger as a radiator, and a refrigerant flow path and heat of the hot water supply heat exchanger. A water flow path in the hot water heat exchanger for exchanging, a water supply pipe for supplying tap water to the water flow path, a hot water supply circuit connected to pass water from the water flow path to the hot water supply terminal, and the hot water supply heat exchange A boiling temperature detection means for detecting the water temperature at the outlet of the water heater, a hot water supply temperature setting means for setting the hot water supply temperature, and in parallel with the hot water supply heat exchanger, and in communication with the hot water supply circuit via the mixing means A hot water storage tank for storing hot water that is hotter than the hot water supply temperature , the plurality of compressors have variable operating frequencies, and when the detected temperature of the boiling temperature detecting means is not more than a predetermined value, the hot water supply Water from the heat exchanger and the hot water storage tank Is characterized in that the the water and configured to mix in said mixing means.
[0015]
According to the present invention, since a plurality of compressors are connected in parallel, the hot water supply load can be varied by changing the compression capacity widely from the operation at the minimum capacity of one compressor to the operation at the maximum capacity of all the compressors. Can handle a wide range of fluctuations. In addition, since the operation frequency of the compressor is variable, it is possible to improve the reliability of the device by operating with as many compressors as possible to disperse the burden on the compressor and to quickly perform the necessary compression. The capacity can be changed to cope with sudden fluctuations in hot water supply load.
[0016]
In the heat pump hot water supply apparatus according to the second aspect of the present invention, all the operating compressors are operated at the same operating frequency.
[0017]
According to the present invention, by operating the compressors to be operated at the same operating frequency, the operating conditions of the compressors that are operating can be made equal, and the concentration of the burden on the compressors can be suppressed.
[0018]
According to a third aspect of the present invention, there is provided a heat pump hot water supply apparatus in which a check valve is provided in the discharge pipe of the compressor according to the first or second aspect.
[0019]
According to this invention, it is possible to prevent the refrigerant discharged from the operating compressor from flowing backward through the stopped compressor and causing a loss. Moreover, since the pressure of the stopped compressor can be maintained at the low pressure side when some of the compressors are operating, the stopped compressor can be started smoothly.
[0020]
According to a fourth aspect of the present invention, there is provided a heat pump hot-water supply apparatus in which the start-up of the compressor according to any one of the first to third aspects is shifted by a predetermined time or more.
[0021]
According to the present invention, the start-up of the compressors is dispersed in time to prevent the load applied when starting up the plurality of compressors from being concentrated.
[0022]
According to a fifth aspect of the present invention, there is provided a heat pump hot water supply apparatus according to any one of the first to fourth aspects, wherein a hot water supply load detecting means for detecting a required hot water supply load is provided.
[0023]
According to this invention, by operating a plurality of compressors in advance with a total operating capacity that is a compression capacity corresponding to the required hot water supply load detected by the hot water supply load detecting means, it is possible to respond to a sudden change in the hot water supply load. Can quickly change the compression capacity.
[0024]
The heat pump hot water supply apparatus of the invention described in claim 6 is the supercritical refrigerant circulation circuit in which the refrigerant pressure is equal to or higher than the critical pressure, wherein the refrigerant circulation circuit according to any one of claims 1 to 5 is used. The flowing water in the water flow path of the hot water supply heat exchanger is heated by the pressurized refrigerant as described above.
[0025]
According to the present invention, the refrigerant flowing through the refrigerant flow path of the hot water supply heat exchanger is pressurized to a pressure higher than the critical pressure by the compressor. Even if it does not condense. Therefore, it becomes easy to form a temperature difference between the refrigerant flow path and the water flow path in the entire hot water supply heat exchanger, so that hot water can be obtained and the heat exchange efficiency can be increased.
[0026]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
[0027]
Example 1
FIG. 1 is a configuration diagram of a heat pump type hot water supply apparatus in an embodiment of the present invention. In FIG. 1, two compressors 22a and 22b having the same specifications provided in parallel by a refrigerant pipe 21, a hot water supply heat exchanger 23 functioning as a radiator, a decompression means 24, and a heat absorber 25 are connected in a closed circuit. Thus, a refrigerant circulation circuit 26 is configured. The refrigerant circulation circuit 26 uses, for example, carbon dioxide as a refrigerant, and uses a supercritical heat pump cycle in which the refrigerant pressure on the high pressure side is equal to or higher than the critical pressure of the refrigerant.
[0028]
The compressors 22a and 22b are independently driven by inverters 27a and 27b that operate at an arbitrary operating frequency. The refrigerant sucked by driving the compressor 22 is compressed to a pressure exceeding the critical pressure and discharged. The discharge pipes of the compressors 22a and 22b are provided with check valves 28a and 28b, respectively.
[0029]
The hot water supply heat exchanger 23 includes a refrigerant flow path 29 through which a refrigerant flows and a water flow path 30 through which water flows, so that heat can be exchanged between the refrigerant and water. A water supply pipe 31 directly connected to the water flow path 30 to supply tap water and a hot water supply circuit 33 for passing hot water discharged from the water flow path 30 to the hot water supply terminals 32a and 32b are connected. The hot water supply heat exchanger 23 is configured so that the flow direction of the refrigerant flow path 29 and the flow direction of the water flow path 30 are opposed to each other and are in close contact with each other so as to facilitate heat transfer. With this configuration, heat transfer between the refrigerant flow path 29 and the water flow path 30 is made uniform, and heat exchange efficiency is improved. In addition, hot water can be discharged.
[0030]
And in the refrigerant circuit side water circuit 34 comprised by the water supply pipe 31 and the water flow path 30 in the hot water supply heat exchanger 23, and the hot water supply circuit 33, the storage tank 35 which stores water higher than hot water supply temperature in parallel with the heat exchanger 23. It has. The storage tank 35 is covered with heat insulating means 36, and water is supplied to the bottom of the storage tank 35 from the water supply pipe 31 through the water supply branch pipe 37, and the piping from the upper part of the storage tank 35 exchanges hot water in the refrigerant circuit side water circuit 34. The mixing means 38 is connected downstream of the vessel 23 so as to be mixed with water from the hot water supply heat exchanger 23 at an arbitrary mixing ratio.
[0031]
In addition, a circulation water channel 39 is provided for taking out water in the storage tank 35 from the bottom, flowing it through the water flow path 30 of the hot water supply heat exchanger 23 and returning it to the top of the storage tank 35, and the water flow path of the hot water supply heat exchanger 23 in the circulation water channel 39. A circulation pump 40 capable of adjusting the flow rate is provided downstream of 30. Regarding such switching of the water channel, a circulating water channel closing valve 41 is provided at the return portion of the circulating water channel 39 to the storage tank 35. When the circulating water channel 39 is not used, the circulating water channel closing valve 41 is closed and the water supply pipe 31 is provided. Is prevented from flowing into the upper portion of the storage tank 35 through the water flow path 30 in the hot water supply heat exchanger 23. In addition, a short-circuit prevention valve 42 is provided in the water supply branch pipe 37, and when the circulation water channel 39 is used, the short-circuit prevention valve 42 is closed and water is short-circuited through the water supply branch pipe 37 by the circulation pump 40 and does not flow. Like that.
[0032]
Control means 43 is provided to control the operating state of the heat pump water heater configured as described above. In order to grasp the operating state of the apparatus, the feed water temperature detecting means 44 for detecting the water temperature in the feed water pipe 31 and the boiling temperature detecting means 45 for detecting the water temperature at the outlet of the hot water supply heat exchanger 23 in the refrigerant circuit side water circuit 34. The hot water supply temperature detecting means 46 for detecting the water temperature immediately before being supplied to the hot water supply terminal 32 on the downstream side of the mixing means 38, the hot water supply flow rate detecting means 47 for detecting the water flow rate, and the storage tank 35 for storing the heat storage amount. Temperature detection means 48a, 48b and 48c are provided and connected to send the detection results to the control means, and the compressors 22a and 22b are individually connected at arbitrary operating frequencies based on the detection results of these detection means. The inverters 27a and 27b to be driven, the decompression means 24, the mixing means 38, and the circulation pump 40 are connected to be controlled by the control means 43. And the hot water supply temperature setting means 49 which a user sets arbitrarily the target temperature of hot water supply is provided, and it connects so that the temperature may be transmitted to the control means 43.
[0033]
The operation and action of the above configuration will be described. In the embodiment shown in FIG. 1, tap water starts to flow from the water supply pipe 31 when the hot water supply terminal 32a or 32b is opened. At this time, the hot water supply flow rate detecting means 47 detects the hot water supply flow rate, calculates the required hot water supply load from the hot water supply temperature detected by the hot water supply temperature detecting means 44 and the hot water supply temperature setting temperature set by the hot water supply temperature setting means 49, and By determining the operating frequency of the two compressors 22a and 22b so as to achieve the compression capacity corresponding to the load, the operation is started with the required compression capacity in advance and the start-up of the apparatus is accelerated. At this time, the compressors 22a and 22b are started after a certain time difference so as not to start at the same time. The apparatus is smoothly started up by dispersing instantaneous load increases such as an increase in current value applied when the compressor is started. Water flowing through the water passage 30 is heated by the high-temperature and high-pressure refrigerant gas discharged from the two compressors 22a and 22b and flowing into the refrigerant passage 29 of the hot water supply heat exchanger 23. Since the refrigerant flowing through the refrigerant flow path 29 of the hot water supply heat exchanger 23 is pressurized to a critical pressure or higher by the compressor, the heat is taken away by the flowing water in the water flow path 30 of the hot water supply heat exchanger 23 and the temperature drops. Will not condense. Therefore, it becomes easy to form a temperature difference between the refrigerant flow path 29 and the water flow path 30 in the entire area of the hot water supply heat exchanger 23, high-temperature hot water can be obtained, and heat exchange efficiency can be increased. On the other hand, the refrigerant cooled by the hot water supply heat exchanger 23 is depressurized by the decompression means 24 and flows into the heat absorber 25, where it absorbs natural energy such as atmospheric heat and solar heat to evaporate and is converted into the compressors 22a and 22b. Return.
[0034]
Since the compressors 22a and 22b are driven by the inverters 27a and 27b, respectively, both the compressors 22a and 22b can be operated from a lower operating frequency to a higher frequency than a certain frequency by the commercial power source, and the total frequency of the two units can be widely used. Can be changed. For example, if the minimum operation frequency is 40 Hz and the maximum operation frequency is 120 Hz, the compression capacity can be changed from a single operation of 40 Hz to a total of 240 Hz corresponding to the operation of two units at 120 Hz. You can respond by changing. Since the operation frequency of both compressors can be changed, if the required compression capacity is equivalent to 80 Hz or more, which is the minimum operation frequency of 40 Hz, the compressor can be operated simultaneously with two units. Can be distributed. By performing this simultaneous operation at the same frequency, it is possible to equalize the operating conditions of the compressor and optimize the distribution of the load applied to each.
[0035]
Furthermore, regarding the circulation of the refrigerant, the discharge amount from each compressor 22a, 22b and the branch amount before suction are equivalent, so that the lubricating oil that circulates in the refrigerant circulation circuit 26 together with the refrigerant is also in each compressor 22a, 22b can be circulated under the same conditions, and the amount of lubricating oil in the compressor can be kept uniform, and a plurality of stable compressors can be operated. Further, the switching of the number of operating compressors is set to 80 Hz which is low in the variable range of the operating frequency. The operating frequency can be continuously changed in a wide range from 80 Hz to 240 Hz, and the compression capability corresponding to the hot water supply load changing rapidly and widely can be quickly changed.
[0036]
Since the check valves 28a and 28b are provided on the discharge sides of the compressors 22a and 22b, respectively, during the one-side operation, for example, when the compressor 22a is operated to stop the compressor 22b, the operation-side compressor The high-pressure refrigerant discharged from 22a flows into the stop-side compressor 22b from the discharge side, passes through the inside of the stop-side compressor 22b, and flows to the suction side of the operation-side compressor 22a, resulting in a loss. To prevent. At this time, since the flow of the refrigerant is stopped on the discharge side, the compressor 22b on the stop side is kept at a low pressure almost equal to the suction pressure of the compressor 22a on the operation side. Therefore, it is possible to smoothly start the compressor 22b on the stop side from the one-side operation of the compressor 22a. Further, since the check valves 28a and 28b are equally provided on the discharge side of both the compressors 22a and 22b, the pressure loss in the check valves 28a and 28b generated during operation is equivalent to that of the compressors 22a and 22b. As a result, the operating conditions can be made equal during simultaneous operation, and one-sided operation can be performed without loss in either compressor 22a, 22b.
[0037]
At the time of start-up, water having a temperature lower than the required hot water supply temperature comes out of the water flow path 30, so that water having a temperature higher than the hot water temperature stored in the storage tank 35 is mixed and heated to supply hot water. At this time, the water in the upper part of the storage tank 35 is pushed out by opening the short-circuit prevention valve 42 and supplying water to the lower part of the storage tank 35. The control means 43 adjusts the mixing ratio of the mixing means 38 so that the temperature of the hot water supply temperature detecting means 46 becomes the hot water supply set temperature required at the hot water supply terminal 32. Then, when the temperature of the water from the refrigerant circuit side water circuit 34 rises, the mixing means 38 is adjusted so as to reduce the mixing ratio from the storage tank 35 side so that the hot water supply temperature becomes the hot water supply set temperature. Thus, hot water is supplied at a required hot water supply temperature immediately after the operation of the refrigerant circulation circuit 26 is started. When the water from the refrigerant circuit side water circuit 34 rises to the hot water supply set temperature, the mixing ratio of the mixing means 38 becomes only the water from the refrigerant circuit side water circuit 34, and hot water is supplied only by heating the refrigerant circuit 26. When heating is performed by a heat pump cycle, if the boiling temperature is increased, the operation efficiency is deteriorated. However, since heating is performed only up to the required hot water supply temperature, an efficient hot water supply operation can be achieved.
[0038]
When the hot water supply terminal 32 is closed and the hot water supply is stopped, the hot water supply flow rate detecting means 47 detects the stop of the hot water supply. A hot water storage operation is performed in which heat is stored in the hot water storage tank 35 using a time during which no hot water is supplied. The heat storage operation is performed by flowing low-temperature water from the bottom of the storage tank 35 to the circulation water channel 39, heating it in the hot water supply heat exchanger 23, and returning it to the top of the storage tank 35. In addition, the use of heat storage during hot water supply operation is performed by supplying hot water from the bottom of the storage tank 35 with water supply and storing the heat from the top to the mixing means. A temperature boundary layer is formed in the storage tank 35 by water having an upper heat storage temperature and water having a lower water supply temperature. Therefore, the heat storage temperature detection means 48a, 48b, 48c provided in the upper part, the middle part, and the lower part of the storage tank 35 are heated to the position of which heat storage temperature detection means 48 from the upper part of the storage tank 35. The amount of stored heat is estimated by detecting whether there is water. Then, when the heat storage amount estimated by the heat storage temperature detecting means 48 becomes a certain amount or less, the heat storage operation is performed. As the heated water is returned to the upper part of the storage tank 35 by performing the heat storage operation, the position of the temperature boundary layer formed between the heated water and the water at the feed water temperature is lowered. In order to increase the amount of heat stored in the storage tank 35 as much as possible and use it effectively, the temperature of the water sent to the hot water supply heat exchanger 23 rises as the temperature of the temperature boundary layer is heated, and the heat pump cycle As the high pressure side rises, the heating capacity must be reduced accordingly.
[0039]
Therefore, in the heat storage operation, either the compressor 22a or 22b is operated alone, and the operating frequency is lowered in accordance with the rise in the temperature of the water sent to the hot water supply heat exchanger 23. It avoids discontinuous changes in compression capacity that occur when switching the number of operating units, and responds to hot water supply loads that change continuously and rapidly. That is, if it is known in advance, it is possible to respond by changing the switching point between the single operation and the two-unit operation. Further, the reliability of the apparatus can be improved by replacing only one compressor of the compressors 22a and 22b by replacing the compressor that performs the single operation according to the accumulation of the operation load and the operation time. You can also. In the present embodiment, two compressors are described, but three or more compressors may be connected in parallel.
[0040]
In this embodiment, the heat pump cycle is a supercritical heat pump cycle in which the pressure of the refrigerant is equal to or higher than the critical pressure. The refrigerant can also be realized by using a chlorofluorocarbon refrigerant, a hydrocarbon refrigerant, or the like. In addition, the effect of each invention in the present embodiment is effective even when used alone.
[0041]
【The invention's effect】
As described above, according to the present invention, it is possible to change the compression capacity widely from the operation at the minimum capacity of one compressor to the operation at the maximum capacity of all the compressors to cope with a wide fluctuation of the hot water supply load. it can. In addition, since all the compressors have variable capacity, they can quickly change to the required compression capacity to cope with sudden fluctuations in the hot water supply load, and operate with as many compressors as possible. The reliability of the apparatus can be improved by distributing the burden on the apparatus.
[Brief description of the drawings]
FIG. 1 is a block diagram of a heat pump water heater in an embodiment of the present invention. FIG. 2 is a block diagram of a conventional heat pump water heater.
DESCRIPTION OF SYMBOLS 22 Compressor 23 Hot water supply heat exchanger 26 Refrigerant circulation circuit 28 Check valve 29 Refrigerant flow path 30 Water flow path 31 Water supply pipe 32 Hot water supply terminal 33 Hot water supply circuit 44 Hot water supply temperature detection means (hot water supply load detection means)
47 Hot water flow rate detection means (hot water load detection means)

Claims (6)

A refrigerant circulation circuit including a plurality of compressors connected in parallel and a hot water supply heat exchanger as a radiator; a water flow path in the hot water supply heat exchanger for exchanging heat with a refrigerant flow path of the hot water supply heat exchanger; A water supply pipe for supplying tap water to the water flow path, a hot water supply circuit connected to pass water from the water flow path to the hot water supply terminal, and a boiling temperature detection for detecting the water temperature at the outlet of the hot water heat exchanger Means, a hot water supply temperature setting means for setting a hot water supply temperature, and a hot water storage device provided in parallel with the hot water supply heat exchanger and in communication with the hot water supply circuit via a mixing means. A plurality of compressors, the operation frequency of the plurality of compressors being variable, and when the detected temperature of the boiling temperature detecting means is not more than a predetermined value, water from the hot water supply heat exchanger and water from the hot water storage tank Are mixed in the mixing means. The heat pump water heater, characterized in that.   The heat pump hot-water supply apparatus according to claim 1, wherein all of the operating compressors are operated at the same operating frequency.   The heat pump hot-water supply apparatus of Claim 1 or 2 which provided the check valve in the discharge pipe of the compressor.   The heat pump hot water supply apparatus according to any one of claims 1 to 3, wherein the start of the plurality of compressors is performed while being shifted by a predetermined time or more.   The heat pump hot-water supply apparatus of Claims 1-4 which provided the hot-water supply load detection means which detects required hot-water supply load.   The refrigerant circulation circuit is a supercritical heat pump cycle in which the pressure of the refrigerant becomes 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. The heat pump hot-water supply apparatus of item 1.

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