JP7262175B2 - heat pump device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a hybrid heat pump device comprising a compression refrigeration cycle and an absorption refrigeration cycle.

Conventional refrigeration cycles include compression refrigeration cycles and absorption refrigeration cycles. In the compression refrigeration cycle, the refrigerant vapor evaporated in the evaporator E is compressed in the compressor P, the high temperature and high pressure refrigerant vapor is cooled and liquefied in the condenser C, and this refrigerant liquid is returned to the evaporator E via the expansion valve. ing. In a heat pump device using this compression refrigeration cycle, by switching the circulation direction of the refrigerant, the user-side heat exchanger can be used as an evaporator for cooling operation, and the user-side heat exchanger can be used as a condenser for heating operation. can.

In the absorption refrigeration cycle, the refrigerant vapor vaporized in the evaporator E is absorbed by the absorption liquid in the absorber A, and the absorption liquid is sent to the regenerator G to be heated to generate and separate the refrigerant vapor from the absorption liquid. The generated refrigerant vapor is led to the condenser C to be cooled and liquefied, and this refrigerant liquid is returned to the evaporator E via the expansion valve. The Dühring diagram is a diagram in which the vertical axis represents the saturation temperature with respect to the vapor pressure of the refrigerant, and the horizontal axis represents the temperature of the refrigerant and the absorbing liquid. a). As shown in FIG. 4(b), the above-mentioned compression refrigeration cycle is shown on a Dühring diagram. As shown in FIG. It is cooled and liquefied at C and returned to the evaporator E.

A compression refrigeration cycle using a compressor is often used as a heat pump device, but it has been proposed to reduce the compression work by incorporating an absorption refrigeration cycle driven by hot water from a solar panel or an engine radiator. ing. For example, in Documents 1 and 2, the same refrigerant is used in the compression refrigeration cycle and the absorption refrigeration cycle, and the evaporator E and the condenser C are shared by both cycles, and the compressor P and the absorption refrigeration cycle are used as shown in FIG. The solution cycles A to G are provided in parallel so that the compression refrigeration cycle and the absorption refrigeration cycle are performed in parallel. Of the amount of refrigerant vapor from the evaporator E, the amount absorbed by the absorber A is compressed in the absorbent solution cycle, so the compression work of the compressor P can be reduced by that amount. Moreover, in Documents 3 and 4, the refrigerants of the compression refrigeration cycle and the absorption refrigeration cycle are separated into separate systems, and the cycles are thermally connected, so that different refrigerants are used in the compression refrigeration cycle and the absorption refrigeration cycle. making it possible. In the example of Document 3, the refrigerant vapor coming out of the evaporator of the compression refrigeration cycle is liquefied on the cooled side of the evaporator of the absorption refrigeration cycle and returned to the inlet side of the evaporator of the compression refrigeration cycle, thereby reducing compression work. ing. In addition, in the example of Document 4, the refrigerant liquid at the outlet of the condenser of the compression refrigeration cycle is subcooled by the cold heat of the absorption refrigeration cycle to increase the cooling capacity without increasing the compression work of the compression refrigeration cycle. The intermediate pressure refrigerant vapor of the stage compressor is cooled by the cold heat of the absorption refrigeration cycle to reduce the compression work required by the compressor.

Heat sources for the absorption refrigeration cycle include heat medium from solar panels, exhaust heat from engines, and exhaust heat from fuel cells. The temperature and amount of heat of the hot water from the engine or fuel cell fluctuate depending on the incident angle of sunlight and the weather, and the operating conditions of the hot water from the engine or fuel cell. If the heat source heat quantity decreases, the absorption refrigeration effect will also decrease accordingly. In particular, when the heat source hot water temperature decreases, the output of the absorption refrigeration cycle will drop sharply, and furthermore, the absorption refrigeration cycle will not work and output will not be possible. Sometimes. The refrigerating capacity, condensing temperature, evaporating temperature, etc. required for the heat pump device are determined from the usage conditions (indoor temperature and humidity, outside air temperature, etc.) of the heat pump device. When the compression refrigeration cycle and the absorption refrigeration cycle are operated in parallel as shown in FIG. If the hot water temperature is less than 100°C, the absorption solution cannot be heated, and the absorption refrigeration cycle fails, resulting in no refrigeration output.

Japanese Patent Publication No. 57-51029 Japanese Patent Application Laid-Open No. 08-145496 Japanese Patent Application Laid-Open No. 2003-307364 JP 2010-271030

The present invention incorporates the effect of the absorption refrigeration cycle into the heat pump device even if the heat source hot water temperature drops or the heat source hot water is relatively low in temperature, and exhibits the effect of reducing the compressor work of the compression refrigeration cycle. This is what I am trying to do.

In the present invention, as shown in FIG. 5(a), the compression mechanism has a two-stage configuration of a low-pressure stage compressor PL and a high-pressure stage compressor PH to reduce the temperature head per stage of the compressor. The intermediate pressure of the compression mechanism is made variable by adjusting the rotation speed of each unit, and it is characterized by being able to flexibly respond to the temperature head and heat source capacity of the absorbent solution cycle. The compression mechanism can be further divided into multiple stages, and the temperature head per stage of the compressor can be further reduced to correspond to the temperature head of the absorbent solution cycle.

A first invention comprises a compression mechanism consisting of a low-pressure stage compressor and a high-pressure stage compressor, a heat source side heat exchanger, a user side heat exchanger, and a refrigerant pipe, wherein the heat source side heat exchanger is a condenser, and the A heat pump device consisting of a compression refrigeration cycle capable of cooling operation using a heat exchanger on the user side as an evaporator, and an absorption refrigeration cycle equipped with a regenerator, an absorber, a solution pipe, and a refrigerant pipe. A part of the refrigerant vapor compressed by the low-pressure stage compressor is guided to the solution side of the absorber, and the refrigerant vapor generated in the regenerator of the absorption refrigeration cycle is guided to the discharge part of the high-pressure stage compressor. there is

FIG. 5(a) shows the state points of this heat pump device on a Dühring diagram. The compression mechanism is a two-stage compressor, and the intermediate pressure can be changed by adjusting the rotation speed. A reduction in compressor work can be achieved. The compressor should preferably have a relief mechanism that operates when overcompression is performed to prevent unnecessary overcompression. That is, when the internal pressure of the compressor becomes higher than the discharge pressure, it is preferable to release the internal pressure to the discharge section.

The third and fourth inventions relate to heating operation. In the heat pump device of the present invention, by switching the refrigerant circulation direction of the compression refrigeration cycle, cooling operation is performed with the use side heat exchanger as the evaporator and the heat source side heat exchanger as the condenser, and the use side heat exchanger as the condenser. Alternatively, the heat source side heat exchanger can be used as an evaporator for heating operation. In the third invention, during heating operation, the absorption refrigeration cycle is disconnected and suspended, and the compression refrigeration cycle performs heating operation. Further, in the fourth invention, only the regenerator part of the absorption refrigeration cycle is incorporated in the compression refrigeration cycle side as an evaporative heater for refrigerant, and the hot water heat source of the absorption refrigeration cycle heats and evaporates the refrigerant from the compression refrigeration cycle for heating. can be used for

The sixth invention provides a steam pipe that can bypass the low-pressure stage compressor, and combines the opening and closing of the valve in the steam pipe with the on/off of the low-pressure stage compressor, so that the absorption refrigeration cycle has a sufficient temperature head. The low-pressure stage compressor can be stopped in some cases.

According to a seventh aspect of the present invention, the compression mechanism has a multi-stage configuration of three or more compressors, thereby making it possible to cope with a smaller temperature head of the absorption refrigeration cycle.

In the present invention, the compression mechanism flexibly responds to the temperature head of the absorption solution cycle that changes with the temperature and heat quantity of the heat source, and the effect of the absorption refrigeration cycle can be taken into the compression refrigeration cycle side, reducing the work of the compressor. can be planned.

1 is a flow sheet showing the configuration of a heat pump device 1 according to an embodiment of Reference Example 1 of the present invention. 1 is a flow sheet showing the configuration of a heat pump device 2 according to a first embodiment of the invention; 2 is a flow sheet showing the configuration of a heat pump device 3 according to a form of Reference Example 2 of the present invention. FIG. 4 is a Dühring diagram for explaining the operating state of a conventional heat pump. FIG. 3 is a Dühring diagram for explaining the operating state of the heat pump of the present invention;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each figure, the same or similar members are denoted by the same or similar reference numerals, and redundant explanations are omitted.
[Reference Example 1]

A heat pump device 1 according to a first embodiment of the present invention will be described with reference to FIG . FIG. 1 is a flow sheet showing a schematic system of the heat pump device 1. FIG. A heat pump device 1 is composed of a compression refrigeration cycle 10 and an absorption refrigeration cycle 50 . The compression refrigeration cycle 10 includes a compression mechanism 20 including a low-pressure stage compressor 21 and a high-pressure stage compressor 22, a user-side heat exchanger 30, and a heat source-side heat exchanger 31 as main components, which are connected by refrigerant piping. By reversing the flow direction at 24, cooling operation and heating operation are switched. The absorption refrigeration cycle 50 has a regenerator 51 and an absorber 52 as main components, and the roles of the condenser and evaporator of the absorption refrigeration cycle are performed by the user-side heat exchanger 30 and the heat source-side heat exchanger 31 of the compression refrigeration cycle. , is shared with the compression refrigeration cycle. The refrigerant is, for example, R134a, which is used in common for both the compression and absorption cycles, the ionic liquid is used as the absorption solution, and the same ionic liquid is used as the compressor lubricating oil, or the highly viscous ionic liquid is used as the lubricating oil.

During the cooling operation of the heat pump device 1, the switching valves V1 and V2 are opened. In the cooling operation of the compression refrigeration cycle 10, the refrigerant vapor from the user-side heat exchanger 30 passes through the refrigerant pipe 43, the four-way valve 24, and the refrigerant pipe 40, is guided to the suction side of the low-pressure stage compressor 21, and Part of the compressed refrigerant vapor goes through the refrigerant pipe 73 to the absorption refrigeration cycle side, and the remainder is sucked into the high-pressure stage compressor 22 and further compressed. Vapor on the discharge side of the high-pressure stage compressor 22 passes through the refrigerant pipe 42, the four-way valve 24, and the refrigerant pipe 44, is led to the heat source side heat exchanger 31, is cooled by an external cooling medium such as outside air, and is condensed. The heat source heat exchanger 31 functions as a condenser, and the condensed liquid passes through the expansion valve 35 and enters the vapor-liquid separator 23. Refrigerant liquid is led to the utilization side heat exchanger 30 through the expansion valve 36 . The utilization-side heat exchanger 30 serves as an evaporator, and the evaporated refrigerant vapor is led to the four-way valve 24 and the refrigerant pipe 40 .

During the heating operation of the heat pump device 1, the switching valves V1 and V2 are closed. In the heating operation of the compression refrigeration cycle 10, the refrigerant vapor from the heat source side heat exchanger 31 passes through the refrigerant pipe 44, the four-way valve 24, and the refrigerant pipe 40, is guided to the suction side of the low pressure stage compressor 21, and is Compressed to intermediate pressure. The intermediate pressure section is cut off from the absorption refrigeration cycle system by the switching valve V1, and the entire amount passes through the refrigerant pipe 41 and is sucked into the high pressure stage compressor 22 and compressed. The discharge-side steam of the high-pressure stage compressor 22 passes through the refrigerant pipe 42, the four-way valve 24, and the refrigerant pipe 43 and is led to the user-side heat exchanger 30 serving as a condenser, where it exerts a heating effect and becomes condensate. The condensed liquid passes through the refrigerant pipe 46 and the expansion valve 36 and enters the gas-liquid separator 23, and the separated refrigerant vapor is led to the intermediate pressure portion between the low-pressure stage compressor 21 and the high-pressure stage compressor 22, The refrigerant liquid is led to the heat source side heat exchanger 31 through the refrigerant pipe 47 and the expansion valve 35 . The heat source side heat exchanger 31 functions as an evaporator that takes heat from an external fluid, and the evaporated refrigerant vapor is guided to the refrigerant pipe 40 via the refrigerant pipe 44 and the four-way valve 24 .

The absorber 52 of the absorption refrigeration cycle absorbs refrigerant vapor from the compression refrigeration cycle guided by the refrigerant pipe 73 during cooling operation. The absorption solution whose temperature rises due to the heat of absorption at that time is cooled by the outside air serving as an external heat source. The absorbent solution that has absorbed the refrigerant passes through the solution pipe 71 by the solution pump 60, recovers heat by the solution heat exchanger 55, is sent to the regenerator 51, and is heated by the hot water of the external heat source supplied through the pipe 51X. and produce refrigerant vapor. The absorbent solution in the refrigerant vapor is separated by the gas-liquid separator 56 , and the refrigerant vapor is discharged to the refrigerant pipe 42 at the discharge portion of the compression mechanism 20 and joins with the refrigerant vapor discharged from the high-pressure stage compressor 22 . The solution from which the refrigerant has been released by the regenerator 52 returns to the absorber 52 through the pipe 72 , the solution heat exchanger 55 and the expansion valve 62 .

During heating operation, the switching valves V1 and V2 are closed, and the absorption refrigeration cycle is suspended. The heat source used as the heat source for the absorption refrigeration cycle during cooling is often used via another device, such as a hot water heater, during heating.

The compression refrigerating cycle of the heat pump device 1 compresses the refrigerant vapor sucked by the low-pressure stage compressor 21 to the discharge pressure of the compression mechanism 20. is sucked by the absorber 52, high-pressure refrigerant vapor is discharged from the regenerator 51, that is, the absorption refrigeration cycle compresses the high-pressure portion, and the remaining refrigerant vapor is compressed by the high-pressure stage compressor 22 to the compression mechanism discharge pressure. Become. Therefore, the work of the compression mechanism can be reduced by the compression work done by the absorption refrigeration cycle system.

The compression mechanism 20 is composed of a low-pressure stage compressor 21 and a high-pressure stage compressor 22, which can be operated separately. The low-pressure stage compressor 21 adjusts the rotation speed based on the cooling load, and the refrigerant flow rate is determined. The rotation speed of the high-pressure stage compressor 22 is adjusted based on the temperature and amount of heat of the heat source driving the absorption refrigeration cycle, and determines the intake amount of the high-pressure stage compressor 22 and the intake amount of the absorber 52 . Alternatively, the target value of the intermediate pressure is determined based on the temperature and heat quantity of the heat source driving the absorption refrigeration cycle, and the rotational speed of the high-pressure stage compressor 22 is adjusted so that the high-pressure stage compressor suction pressure reaches the target pressure. may

If the steam pipe 40a indicated by the broken line and having the switching valve V3 is provided in the heat pump device 1 of FIG. be able to. If necessary, a check valve 23 is provided on the discharge side of the high-pressure stage compressor to prevent backflow.
When the switching valve V3 is closed and the switching valves V1 and V2 are opened, the low-pressure stage compressor 21, the high-pressure stage compressor 22, and the absorption refrigeration cycle 50 are operated. Compression work of the compressor 22 can be reduced. If the amount of heat source heat does not run short even if the high-pressure stage compressor 22 is stopped in this operating state, the work of the high-pressure stage compressor 22 can be eliminated.
If the heat source temperature is high or the outside air temperature is low, and the temperature head from the evaporation temperature to the condensation temperature in the compression refrigeration cycle can be created even in the absorption refrigeration cycle, the switching valve V3 is opened, the switching valve V1 is closed, and the switching valve V2 is opened. , the compression mechanism 20 and the absorption refrigeration cycle 50 can be operated to reduce the compression work in the low and high pressure stages. Incidentally, if the required head is low, the low-pressure stage compressor 21 may be stopped. If the heat source heat quantity is sufficient even if the compression mechanism 20 is stopped, the cooling load can be covered by the absorption refrigeration cycle 50 alone, and the work of the compression mechanism 20 can be eliminated.
When the heat source temperature is very low or the heat source heat quantity cannot be obtained, the switching valves V1, V2, and V3 are all closed to stop the absorption refrigeration cycle 50, and the compression refrigeration cycle 10 alone can perform cooling operation. .
[ Example 1]

A heat pump device 2 according to a first embodiment of the present invention will be described with reference to FIG. In the absorption refrigeration cycle, unlike Reference Example 1 , the absorbent solution can be cooled by an external heat source in the cooler 52b, and the refrigerant vapor can be absorbed by the cooled absorbent solution in the absorption chamber 52a. .

During the heating operation, the switching valve V1 of the refrigerant supply pipe to the absorber is closed, and the switching valves V6 and V7 of the inlet/outlet of the absorbent solution to the regenerator 51 are closed to suspend the absorption refrigeration cycle. Refrigerant liquid from the user-side heat exchanger 30 is introduced into the regenerator 51 during heating by a refrigerant pipe 82 and a refrigerant pump 83, and the introduced refrigerant is heated and evaporated by the driving heat source, and the heat of the user-side heat exchanger 30 is evaporated. It is supplied to the inlet side together with the refrigerant vapor on the high pressure stage discharge side of the compression refrigeration cycle system. In this embodiment, the regenerator is disconnected from the solution circulation system during heating operation, the refrigerant liquid at the outlet of the use-side heat exchanger 30 is led to the regenerator 51, and the refrigerant is heated by the heat source. Alternatively, a refrigerant heater capable of heating the refrigerant with a heat source may be provided to supply the refrigerant liquid and heat and evaporate it.

In this embodiment, as a method of defrosting the compression refrigeration cycle during heating operation, a refrigerant pipe 80 and an expansion valve 81 indicated by broken lines are used to transfer refrigerant vapor from the discharge portion of the compression mechanism 20 to the heat source side heat exchanger 31. Adopts a hot gas bypass system that leads to the inlet side. In addition to this defrosting method, there is a reverse cycle method of defrosting by reversing the flow of refrigerant, and various defrosting methods used in compression heat pumps can be applied to this heat pump device.
[Reference example 2 ]

A heat pump device 3 according to a second embodiment of the present invention will be described with reference to FIG. The compression refrigeration cycle 10 and the absorption refrigeration cycle 50 are thermally connected via an evaporator 54 of the absorption refrigeration cycle without medium transfer between the cycles. Different refrigerants can be used in both cycles, for example water/lithium bromide solution in the absorption refrigeration cycle and HFC refrigerant R32 in the compression refrigeration cycle.

The compression refrigeration cycle 10 includes a compression mechanism 20 consisting of a low-pressure stage compressor 21 and a high-pressure stage compressor 22, a user-side heat exchanger 30, and a heat source-side heat exchanger 31 as main components, which are connected by refrigerant pipes to perform cooling operation. The flow direction is reversed by the four-way valve 24 between the heating operation and the heating operation. In the cooling operation of the compression refrigeration cycle 10, the refrigerant vapor from the user-side heat exchanger 30 is guided through the refrigerant pipe 43, the four-way valve 24, and the refrigerant pipe 40 to the suction side of the low-pressure stage compressor 21, and The refrigerant vapor compressed to pressure is led through the refrigerant pipe 41a to the evaporator 54 of the absorption refrigeration cycle and cooled. . The refrigerant vapor separated from gas and liquid by the gas-liquid separator 23 is sucked into the high-pressure stage compressor 22 and further compressed. Vapor on the discharge side of the high-pressure stage compressor 22 is led to the heat source side heat exchanger 31 through the refrigerant pipe 42, the four-way valve 24, and the refrigerant pipe 44, cooled by an external cooling medium such as outside air, and condensed. The heat source heat exchanger 31 functions as a condenser, and the condensed liquid enters the gas-liquid separator 23 through the expansion valve 35, the refrigerant liquid four-way valve 37, and the refrigerant pipe 45a. The refrigerant liquid separated by the gas-liquid separator 23 passes through the refrigerant pipe 45b, the four-way valve 37, and the expansion valve 36 together with the refrigerant liquid condensed by the evaporator 54 of the absorption refrigeration cycle described above, and is sent to the utilization side heat exchanger 30. be guided. The user-side heat exchanger 30 functions as an evaporator, and the evaporated refrigerant vapor is guided to the refrigerant pipe 43 , the four-way valve 24 , and the refrigerant pipe 40 .

The absorption refrigeration cycle 50 has a regenerator 51, a condenser 53, an absorber 52, and an evaporator 54 as main components, and performs a single-effect absorption refrigeration cycle during cooling operation. In Reference Example 2 , water is used as the refrigerant, and since the evaporation pressure is low, the liquid film type evaporator 54 is used, and the refrigerant is circulated and sprayed by the refrigerant pump 61 . If the refrigerant has a certain level of refrigerant pressure and the liquid height does not affect boiling, the evaporator can be filled with liquid, and the refrigerant pump can be eliminated.

When the heat pump device 3 performs heating operation, the switching valves V1, V3 and V4 are closed to suspend the absorption refrigeration cycle, and the switching valve V5 is opened to bypass the evaporator 54 of the absorption refrigeration cycle. In the heating operation of the compression refrigeration cycle, the four-way valve 24 on the steam side and the four-way valve 37 on the liquid side are switched, and the four-way valve 24 transfers the steam discharged from the high-pressure compressor 22 to the heat exchanger 30 on the heat source side. Refrigerant vapor from the exchanger 31 is led to the suction portion of the low-pressure stage compressor 21, and the refrigerant liquid side four-way valve 37 allows the refrigerant liquid from the user side heat exchanger 30 to flow through the expansion valve 36 to the gas-liquid separator. 23 , and the separated refrigerant liquid is circulated through the expansion valve 35 to the heat source side heat exchanger 31 .

In the explanation so far, the absorption refrigeration cycle is driven by using hot water as a heat source, but the absorption solution may be sent to the heat generating section to directly receive the heat. For example, the solution fed to regenerator 51 may be fed to a solar collector (not shown), and the absorbent solution may be returned to a vessel without heat transfer surfaces or to the regenerator 51 portion as a gas-liquid separator. Alternatively, a solution pump may be used to circulate the absorbent solution between the regenerator 51 having no heat transfer surface and the solar heat collector. By using an ionic liquid as the absorption solution, it can be circulated as needed without freezing or crystals.

10 Compression refrigeration cycle 20 Compression mechanism 21 Low-pressure stage compressor 22 High-pressure stage compressor 24 Refrigerant vapor four-way valve 30 Utilization side heat exchanger 31 Heat source side heat exchangers 35, 36 Expansion valve 37 Refrigerant liquid four-way valves 40 to 47 Refrigerant piping 50 Absorption refrigeration cycle 51 regenerator 52 absorber 53 condenser 54 evaporator 55 solution heat exchanger 60 absorption solution pump 61 refrigerant pump 62 expansion valves 71 to 75 solution piping, refrigerant piping 80, 82 refrigerant piping 81 expansion valve 83 refrigerant pump V1 , V2, V3, V4, V5, V6, V7 switching valve

Claims (4)

A heat pump device comprising a compression refrigeration cycle comprising a compression mechanism, a heat source side heat exchanger, a user side heat exchanger and refrigerant piping, and an absorption refrigeration cycle comprising a regenerator, an absorber, a solution piping and the refrigerant piping. hand,
The compression mechanism is composed of a low-pressure stage compressor and a high-pressure stage compressor, and the low-pressure stage compressor suction side is arranged on the low-pressure suction side of the compression mechanism, and the high-pressure stage compressor discharge side is arranged on the high pressure discharge side of the compression mechanism. death,
connecting the low pressure stage compressor discharge side and the high pressure stage compressor suction side,
In the compression refrigerating cycle, the heat source side heat exchanger is connected to the high pressure discharge side of the compression mechanism, and the user side heat exchanger is connected to the low pressure suction side of the compression mechanism by the refrigerant pipes to enable cooling operation. ,
guiding the refrigerant vapor on the discharge side of the low-pressure stage compressor to the solution side of the absorber;
guiding the refrigerant vapor generated from the solution in the regenerator to the discharge side of the compression mechanism;
During cooling operation, the compression refrigeration cycle connects the heat source side heat exchanger to the high pressure discharge side of the compression mechanism and connects the user side heat exchanger to the low pressure suction side of the compression mechanism to enable cooling operation. while operating the absorption refrigeration cycle,
During heating operation, the compression refrigeration cycle connects the heat source side heat exchanger to the low pressure suction side of the compression mechanism and connects the user side heat exchanger to the high pressure discharge side of the compression mechanism to enable heating operation. and the absorption refrigeration cycle is characterized in that the absorption refrigeration cycle closes the entrance and exit of the absorption solution to and from the regenerator, and guides the refrigerant liquid at the outlet of the use-side heat exchanger to the regenerator. 2. The apparatus according to claim 1, wherein the rotation speed of said low-pressure stage compressor is used to adjust the output of said utilization side heat exchanger, and the rotation speed of said high-pressure stage compressor is used to adjust the refrigerant flow rate to said absorption refrigeration cycle. A heat pump device as described. 3. The heat pump apparatus according to claim 1, further comprising a steam pipe having a valve bypassing said low-pressure stage compressor. The heat pump device according to any one of claims 1 to 3, wherein the compression mechanism has a multi-stage configuration including three or more compressors.

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