JP5606262B2 - Heat pump system - Google Patents

Description

  The present invention relates to a heat pump system.

  2. Description of the Related Art Conventionally, in a heat pump system, a vehicle air conditioner is known in which oil contained in refrigerant discharged from a compressor (compressor) is returned to the compressor by a return flow rate adjusting unit (see, for example, Patent Document 1). ).

JP 2002-267282 A

  The air conditioner disclosed in Patent Document 1 described above provides a vehicle air conditioner that can reliably return the refrigerant to the compressor in a superheat state even with a simple and inexpensive configuration without an accumulator. For this reason, an oil separator that separates oil from the refrigerant discharged from the compressor is provided. By connecting an oil return pipe that returns the oil separated by the oil separator to the compressor in the middle of a pipe connecting the vehicle inner heat exchanger and the compressor, the refrigerant from the vehicle inner heat exchanger is completely vaporized. Yes.

  However, in the air conditioner of Patent Document 1, it is difficult to always maintain the refrigerant sucked into the compressor in the heated gas when the load fluctuates suddenly at the time of start-up, so an accumulator is eventually required before the compressor. If the oil separated by the oil separator is circulated before the accumulator, the oil accumulates in the accumulator, and as a result, the compressor may run out of oil. On the other hand, when the oil is circulated after the accumulator, the refrigerant sucked into the compressor is heated by the amount of heat of the oil. As a result, the compressor discharge temperature may increase excessively.

  The present invention solves the above-described problems, and an object of the present invention is to provide a heat pump system that can circulate oil to a compressor while keeping the refrigerant in a heated gas even when the load fluctuates rapidly.

In order to achieve the above-described object, the heat pump system of the present invention includes a compressor that compresses a refrigerant, an oil separator that separates oil contained in the compressed refrigerant, and the content of the oil by the oil separator. A first heat exchanger that dissipates the reduced heat of the refrigerant; a decompression unit that reduces the pressure of the refrigerant dissipated by the first heat exchanger; and a second that causes the decompressed refrigerant to absorb heat. A heat exchanger, a third heat exchanger that radiates heat of the oil separated by the oil separator and heats the refrigerant that has absorbed heat by the second heat exchanger, and the third heat exchanger. And an accumulator that separates the liquid phase from the refrigerant heated in step and sucks the refrigerant after the liquid phase is separated into the compressor , and radiates heat in the third heat exchanger. The compression Refrigerant to be allowed passage inhalation connects the flow passage of the refrigerant after separating the liquid phase in the accumulator, after the third of the oil that is radiated by the heat exchanger were separated liquid phase in said accumulator And sucked into the compressor.

  In the heat pump system according to the present invention, since oil is sucked into the compressor without passing through the accumulator, the oil does not accumulate in the accumulator. Moreover, since the heat of oil is radiated by the third heat exchanger, the refrigerant sucked into the compressor is overheated by the amount of heat of the oil, and the possibility that the discharge temperature of the compressor is excessively increased is reduced. Thereby, in the heat pump system, the accumulator and the oil separator can coexist without interfering with each other. As a result, since the accumulator is provided, the refrigerant can be kept in the heated gas even if the load fluctuates rapidly. Further, since the oil separator is provided, the oil is circulated to the compressor. As a result, the risk that the compressor will run out of lubricating oil can be reduced. Furthermore, since the third heat exchanger can dissipate the heat of the oil and heat the refrigerant that has absorbed heat by the second heat exchanger, the second heat exchanger is operated by gas-liquid two-phase mixing. Can do. A second heat exchanger operating with gas-liquid two-phase mixing can increase efficiency.

  As a desirable mode of the present invention, the heat pump system obtains the degree of superheat from the temperature sensor that measures the temperature of the refrigerant heated by the third heat exchanger, and the temperature of the refrigerant measured by the temperature sensor. And a control device that controls the decompression unit according to the obtained degree of superheat. According to this heat pump system, the degree of superheat at which the refrigerant sucked into the compressor is heated can be controlled. As a result, the possibility that the discharge temperature of the compressor will rise excessively is reduced.

  According to the present invention, oil can be circulated while keeping the refrigerant in the heated gas even if the load fluctuates rapidly.

FIG. 1 is a schematic diagram of a heat pump system according to the first embodiment. FIG. 2 is a configuration diagram of a heat pump system according to the second embodiment. FIG. 3 is a flowchart for explaining the operation of the control device. FIG. 4 is a configuration diagram of a heat pump system according to the third embodiment.

  DESCRIPTION OF EMBODIMENTS Embodiments (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited by the contents described in the following embodiments. The constituent elements described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the constituent elements described below can be appropriately combined.

(Embodiment 1)
FIG. 1 is a schematic diagram of a heat pump system according to the present embodiment. As shown in FIG. 1, the heat pump system 1 of this embodiment includes a compressor 11, an oil separator 12, an accumulator 13, a capillary 14, an expansion valve 20, heat exchangers 21, 22, and 23, and a refrigerant. It has flow paths 15A, 15B, 15C, 15D, 15E, 15F, and 15G, and oil flow paths 16A, 16B, and 16C.

For example, in the heat pump system 1 of the present embodiment, the heat pump system will be described as a hot water supply device. In the hot water supply apparatus, the heat exchanger 21 is an outdoor heat exchanger, and the heat exchanger 22 is an indoor heat exchanger. For example, the refrigerant is carbon dioxide (CO ₂ ). The refrigerant may be any other refrigerant and is not limited.

  The compressor 11 is a device that compresses and mechanically pressurizes the refrigerant that has absorbed heat in the heat exchanger 21 and then discharges the refrigerant to the heat exchanger 22. The compressor 11 can compress the refrigerant by using the centrifugal force of the rotating blades to scatter the refrigerant radially and decelerate it with a diffuser. Or the compressor 11 can take the system which compresses a refrigerant | coolant with a piston within a cylinder. The compressor 11 is a method in which the refrigerant is compressed by rotating an eccentric rotor in a cylindrical cylinder and crushing the partition space, a method of compressing by eccentric swirling in combination with a spiral scroll, or other known methods. Can be compressed.

  The oil separator 12 is an oil separator that separates the lubricating oil (oil) of the compressor 11 contained in the refrigerant discharged from the compressor 11 from the refrigerant. The oil separator 12 is made liquid by dripping mist-like oil contained in the refrigerant with a separation plate or the like, and can store a predetermined amount of oil. Or the oil separator 12 is good also as a cyclone-type oil separator which introduce | transduces a refrigerant | coolant so that it may spirally move along the inner surface of the trunk | drum wall of an airtight container. In the course of this spiral motion, the refrigerant collides with the inner surface of the barrel wall, and the oil contained in the form of mist is separated and falls along the inner surface of the barrel wall, and the oil is stored at the bottom of the oil separator.

  The accumulator 13 separates the refrigerant that has absorbed heat by the heat exchanger 21 into a liquid refrigerant (liquid phase) and a gaseous refrigerant (gas phase), and causes the compressor 11 to suck the refrigerant after the liquid phase is separated. Device. The refrigerant sucked into the compressor 11 by the accumulator 13 can be mainly heated gas. The capillary 14 is an oil flow rate adjusting throttle tube.

  The expansion valve 20 is a decompression unit that adiabatically expands the refrigerant to reduce the pressure of the refrigerant. The heat exchanger 21 acts as an evaporator that absorbs heat from the decompressed refrigerant. The heat exchanger 22 acts as a radiator that radiates the heat of the refrigerant compressed by the compressor 11.

  The heat exchanger 23 is a heat exchanger that exchanges heat between the refrigerant flowing from the heat exchanger 21 to the accumulator 13 and the heat of the oil, radiates the heat of the oil, and heats the refrigerant. For example, the heat exchanger 23 is a double pipe heat exchanger in which oil is an inner pipe and refrigerant flows through an outer pipe. In the heat exchanger 23, it is desirable that the refrigerant flow direction and the oil flow direction are counterflows. When the counter flow is used, heat exchange between the refrigerant and the oil is efficiently performed.

  The refrigerant flow paths 15A, 15B, 15C, 15D, 15E, 15F, and 15G are flow path systems that circulate the refrigerant of the heat pump system 1. The refrigerant channel 15 </ b> A is a channel that conveys the refrigerant from the compressor 11 to the oil separator 12. The refrigerant flow path 15 </ b> B is a flow path for conveying the refrigerant from the oil separator 12 to the heat exchanger 22. The refrigerant channel 15 </ b> C is a channel that conveys the refrigerant from the heat exchanger 22 to the expansion valve 20. The refrigerant flow path 15D is a flow path for conveying the refrigerant from the expansion valve 20 to the heat exchanger 21. The refrigerant flow path 15E is a flow path for conveying the refrigerant from the heat exchanger 21 to the heat exchanger 23. The refrigerant flow path 15 </ b> F is a flow path for conveying the refrigerant from the heat exchanger 23 to the accumulator 13. The refrigerant flow path 15 </ b> G is a flow path for conveying the refrigerant from the accumulator 13 to the compressor 11.

  The oil flow paths 16A, 16B, and 16C are flow path systems that circulate oil from the oil separator 12 to the compressor 11 via the heat exchanger 23. The oil flow path 16 </ b> A is a flow path for conveying oil from the oil separator 12 to the heat exchanger 23. The oil channel 16B is a channel for conveying oil from the heat exchanger 23 to the capillary 14. The oil flow path 16C is a flow path that is connected to the refrigerant flow path 15G at the connection point 17 in order to suck oil from the capillary 14 into the compressor 11.

  Next, the operation of the heat pump system 1 will be described using a hot water supply device in which the heat exchanger 21 is an outdoor heat exchanger and the heat exchanger 22 is an indoor heat exchanger. The refrigerant compressed by the compressor 11 is discharged to the oil separator 12 via the refrigerant flow path 15A. The carbon dioxide of the refrigerant whose pressure has been increased by compression is in a supercritical state.

  In the oil separator 12, mist-like oil contained in the refrigerant is dropped by the inner surface of the barrel wall or the like in the process of the separation plate or spiral motion, and becomes liquid. The refrigerant whose oil content has been reduced by the oil separator 12 is conveyed to the heat exchanger 22 via the refrigerant flow path 15B. The heat exchanger 22 is connected to, for example, a hot water storage tank (not shown) in which low temperature hot water and high temperature hot water are stored in a layered state. Hot water circulates between the hot water storage tank and the heat exchanger 22. In the heat exchanger 22, the heat of the refrigerant is dissipated, and heat exchange between the refrigerant and the low-temperature hot water makes the low-temperature hot water hot water.

  The refrigerant radiated by the heat exchanger 22 is conveyed to the expansion valve 20 via the refrigerant flow path 15C. In the expansion valve 20, the refrigerant is adiabatically expanded and the pressure of the refrigerant is reduced. Therefore, the expansion valve 20 serves as a pressure reducing unit that reduces the pressure of the radiated refrigerant.

  The decompressed refrigerant is conveyed to the heat exchanger 21 via the refrigerant flow path 15D. In the heat exchanger 21, the decompressed refrigerant absorbs heat from the outside air (outdoor air) and evaporates to form a gaseous refrigerant. For example, outside air is blown to the heat exchanger 21 by an electric fan.

  The refrigerant that has absorbed heat is conveyed to the heat exchanger 23 via the refrigerant flow path 15E. Oil recovered by the oil separator 12 is conveyed to the heat exchanger 23 via the oil flow path 16A. The oil to be conveyed has a high temperature of 100 ° C., for example. The heat exchanger 23 exchanges heat between the oil and the refrigerant, and the refrigerant is heated by the amount of heat of the oil. For example, in the heat exchanger 23, the temperature of the oil is reduced to 60 ° C.

  The refrigerant heated in the heat exchanger 23 is conveyed to the accumulator 13 via the refrigerant flow path 15F. In the accumulator 13, the refrigerant flowing in is separated into gas and liquid. In the heat pump system 1 of the present embodiment, even if a liquid-rich refrigerant comes to the accumulator 13 at the time of system startup, the liquid refrigerant (liquid phase) is supplied to the compressor 11 because the accumulator performs gas-liquid separation into liquid refrigerant and gaseous refrigerant. Is not inhaled.

  The refrigerant is conveyed from the accumulator 13 to the compressor 11 via the refrigerant flow path 15G. Oil is supplied from the heat exchanger 23 to the capillary 14 via the oil flow path 16B. After the oil flow rate is adjusted by the capillary 14, the oil is conveyed to the compressor 11 via the oil flow path 16 </ b> C, the connection point 17, and the refrigerant flow path 15 </ b> G.

  The refrigerant discharged from the compressor 11 enters the heat exchanger 22 as an indoor heat exchanger and is cooled by exchanging heat with hot water sent from the hot water storage tank, as indicated by solid arrows. This refrigerant is preferably expanded under reduced pressure by the expansion valve 20 to be gas-liquid two-phase mixed. This gas-liquid two-phase mixed refrigerant enters the heat exchanger 21 which is an outdoor heat exchanger and evaporates into a gaseous refrigerant by exchanging heat with the air sent by the electric fan. In the heat pump system 1 of the present embodiment, the refrigerant is preferably gas-liquid two-phase mixed in the entire area of the heat exchanger 21 in order to increase the efficiency of the heat exchanger 21. Even if the refrigerant is gas-liquid two-phase mixed at the outlet of the heat exchanger 21, the refrigerant is heated by the heat exchanger 23, and the liquid phase can be reduced in a subsequent process. The refrigerant separates the liquid phase via the accumulator 13, is sucked into the compressor 11 in the state of heated gas, and is compressed again by the compressor 11.

  In the heat pump system 1 of the present embodiment, the compressor 11 that compresses the refrigerant, the oil separator 12 that separates the oil contained in the compressed refrigerant, and the heat of the refrigerant whose oil content has been reduced by the oil separator 12 are dissipated. A heat exchanger 22 that is a first heat exchanger to be performed, an expansion valve 20 that is a decompression unit that reduces the pressure of the refrigerant radiated by the heat exchanger 22, and a second heat exchange that absorbs heat from the decompressed refrigerant. Heat that is a third heat exchanger that heats the refrigerant that has been absorbed by the heat exchanger 21 by dissipating the heat of oil that is separated by the oil separator 12 and sucked into the compressor 11 And an accumulator 13 that separates the liquid phase from the refrigerant heated by the heat exchanger 23 and causes the compressor 11 to suck the refrigerant after the liquid phase is separated. In the heat pump system 1 of the present embodiment, the oil radiated by the heat exchanger 23 is sucked into the compressor 11 together with the refrigerant after the liquid phase is separated by the accumulator 13.

  For this reason, in the heat pump system 1, the oil is sucked into the compressor 11 without passing through the accumulator 13, so that the oil does not accumulate in the accumulator 13. Further, since the heat of the oil is radiated by the third heat exchanger 23, the refrigerant sucked into the compressor 11 is overheated by the amount of heat of the oil, and the possibility that the discharge temperature of the compressor 11 rises excessively is reduced. To do. As a result, it is possible to reduce the possibility that the discharge temperature of the compressor 11 will rise excessively under conditions where the outdoor air temperature is low. In the heat pump system 1, the accumulator 13 and the oil separator 12 can coexist without interfering with each other. As a result, since the accumulator 13 is provided, the refrigerant can be kept in the heated gas even if the load fluctuates rapidly. Further, since the oil separator 12 is provided, the oil is circulated to the compressor 11. Since the oil which is the lubricating oil of the compressor 11 is circulated, it is possible to reduce the possibility that the compressor 11 will run out of lubricating oil.

  In the heat pump system 1 of the present embodiment, the heat exchanger 23 can dissipate the heat of the oil and heat the refrigerant that has absorbed heat by the heat exchanger 21, so that the heat exchanger 21 is operated by gas-liquid two-phase mixing. be able to. The heat exchanger 21 as an evaporator can be operated with higher efficiency when operated by gas-liquid two-phase mixing than when operated by a gas phase alone.

  Moreover, as a modification, an intercooler (intercooler) that performs heat exchange between the refrigerant supplied from the heat exchanger 21 of the heat pump system 1 and the refrigerant supplied from the heat exchanger 22 may be used. The intercooler (intermediate cooler) heats the refrigerant supplied from the heat exchanger 21 and cools the refrigerant supplied from the heat exchanger 22. In this case, since the heat exchanger 23 can be heated to reduce the liquid phase, it has the same effect as the intercooler, and the intercooler becomes unnecessary or the heat capacity of the intercooler can be reduced.

  The heat pump system 1 is not limited to a hot water supply device, and may be applied to an air conditioner, a refrigeration device, a cooling device, and a heating device.

(Embodiment 2)
FIG. 2 is a configuration diagram of a heat pump system according to the second embodiment. The heat pump system 2 according to the present embodiment is characterized in that it detects the degree of superheat of the refrigerant between the heat exchanger 21 and the accumulator 13 and controls the degree of superheat of the refrigerant flowing into the accumulator 13. In the following description, the same components as those described in the first embodiment are denoted by the same reference numerals, and redundant descriptions are omitted.

  The heat pump system 2 illustrated in FIG. 2 includes the configuration of the heat pump system 1 described in the first embodiment, a control device 41, a temperature sensor 42, and a pressure sensor 43.

  The control device 41 can also be realized by being executed by a computer system such as a personal computer, a workstation, or a microcomputer (control computer). The control device 41 includes at least a storage unit (not shown) configured by a CPU, a RAM, a ROM, and the like and storing programs and data. The control device 41 is connected to the expansion valve 20, the temperature sensor 42, and the pressure sensor 43.

  The temperature sensor 42 is a measuring instrument that can measure the temperature of the refrigerant. The pressure sensor 43 is a measuring instrument that can measure the pressure of the refrigerant. The temperature sensor 42 and the pressure sensor 43 measure the temperature and pressure of the refrigerant in the refrigerant flow path 15F. In other words, the temperature sensor 42 and the pressure sensor 43 measure the temperature and pressure of the refrigerant heated by the heat exchanger 23 before the refrigerant is supplied to the accumulator 13. Note that the pressure sensor 43 may be attached to a place other than the refrigerant flow path 15F (for example, the refrigerant flow path 15E) as long as the pressure of the refrigerant flow path 15F can be easily estimated.

  In the heat pump system 2, the control device 41 controls the opening and closing of the expansion valve 20. FIG. 3 is a flowchart for explaining the operation of the control device. As shown in FIG. 3, the control device 41 starts control of the heat pump system 2. First, the control device 41 causes the temperature sensor 42 and the pressure sensor 43 to measure temperature data and pressure data (step S1). Next, the control device 41 receives temperature data and pressure data from the temperature sensor 42 and the pressure sensor 43 and stores them in the storage unit in the control device 41. The control device 41 calculates the degree of superheat from the stored temperature data and pressure data (step S2). The degree of superheat is the difference between the temperature of the superheated steam of the refrigerant measured by the temperature sensor 42 and the pressure saturation temperature converted from the pressure measured by the pressure sensor 43.

  Next, the control device 41 compares the reference superheat degree stored in advance with the calculated superheat degree, and determines whether or not control is necessary (step S3). When control is unnecessary (step S3: No), the control apparatus 41 returns operation | movement to step S1, and the temperature sensor 42 and the pressure sensor 43 measure temperature data and pressure data. The determination of the necessity of control will be specifically described. When the reference superheat degree and the calculated superheat degree are equal, it is determined that the control is unnecessary. When control is required (step S3: Yes), the control device 41 controls the expansion valve 20 (step S4). Specifically, when the calculated superheat degree is higher than the reference superheat degree, the control device 41 performs control to open the opening degree of the expansion valve 20 so as to approach the reference superheat degree. Conversely, when the calculated superheat degree is lower than the reference superheat degree, the control device 41 performs control to bring the opening degree of the expansion valve 20 close to the throttle reference superheat degree. The control device 41 ends the operation after controlling the expansion valve 20. Note that the control device 41 restarts the control of the heat pump system 2 if necessary.

  In the present embodiment, the temperature sensor 42 and the pressure sensor 43 are made to measure temperature data and pressure data in order to calculate the degree of superheat. As another modification, the pressure sensor 43 is omitted, another temperature sensor for measuring the evaporation pressure saturation temperature of the heat exchanger 21 is provided, and the outlet temperature measured by the other temperature sensor is set to the pressure saturation temperature described above. The degree of superheat may be calculated by assuming that

  The heat pump system 2 of the present embodiment obtains the degree of superheat from the temperature sensor 42 that measures the temperature of the refrigerant heated by the heat exchanger 23, and the temperature of the refrigerant measured by the temperature sensor 42, and according to the obtained degree of superheat. And a control device 41 for controlling the expansion valve 20 which is a decompression unit. According to the heat pump system 2, the degree of superheat at which the refrigerant sucked into the compressor 11 is heated can be controlled. As a result, the possibility that the discharge temperature of the compressor 11 will rise excessively is reduced.

(Embodiment 3)
FIG. 4 is a configuration diagram of a heat pump system according to the third embodiment. The heat pump system 3 according to the present embodiment has a four-way valve 31 and is characterized in that the roles of the heat exchanger 21 and the heat exchanger 22 can be changed. In the following description, the same components as those described in the first embodiment are denoted by the same reference numerals, and redundant descriptions are omitted.

  The heat pump system 3 illustrated in FIG. 4 includes the configuration of the heat pump system 1 described in the first embodiment, and further includes a four-way valve 31, a refrigerant flow path 15H, and a refrigerant flow path 15I.

  The four-way valve 31 is a connection valve for switching four-way piping for each system. For example, when the heat pump system 3 is an air conditioner, the flow of the evaporator and the condenser can be reversed during cooling operation and heating operation by switching the system of the four-way valve 31. In the heat pump system 3 of the present embodiment, the four-way valve 31 is connected to the discharge side of the compressor 11 through the refrigerant flow path 15H. The four-way valve 31 is connected to a refrigerant flow path 15I on the suction side of the compressor 11. The four-way valve 31 shown in FIG. 4 includes a system indicated by a solid line (four-way valve flow path 32a and four-way valve flow path 32c) and a line indicated by a dotted line (four-way valve flow path 32b and four-way valve flow path 32d). have. In the case of the system indicated by the solid line, the refrigerant flow path 15H is connected to the refrigerant flow path 15B via the four-way valve inner flow path 32a, and the refrigerant flow path 15E is connected to the refrigerant flow path 15I via the four-way valve inner flow path 32c. ing. When switching to the system shown by the dotted line, the refrigerant flow path 15H is connected to the refrigerant flow path 15E via the four-way valve internal flow path 32b, and the refrigerant flow path 15B is connected to the refrigerant flow path 15I via the four-way internal valve flow path 32d. doing.

  During the heating operation, the refrigerant discharged from the compressor 11 passes through the four-way valve 31 and enters the heat exchanger 22 serving as the indoor heat exchanger, and exchanges heat with the air sent by the indoor fan, as indicated by solid arrows. To condense into a liquid refrigerant. For this reason, the heat exchanger 22 acts as a condenser. This liquid refrigerant is decompressed and expanded by the expansion valve 20 to be gas-liquid two-phase mixed. This gas-liquid two-phase mixed refrigerant enters the heat exchanger 21 which is an outdoor heat exchanger, and evaporates into a gas by exchanging heat with the air sent by the outdoor fan. For this reason, the heat exchanger 21 acts as an evaporator. The gas refrigerant is sucked into the compressor 11 via the four-way valve 31, the heat exchanger 23, and the accumulator 13 and is compressed again by the compressor 11. During the cooling operation, switching the four-way valve 31 causes the refrigerant to circulate as indicated by the broken line arrows. The refrigerant discharged from the compressor 11 passes through the four-way valve 31 and enters the heat exchanger 21 serving as the indoor heat exchanger, and is condensed by exchanging heat with the air sent by the indoor fan, as indicated by the broken arrow. It becomes a liquid refrigerant. For this reason, the heat exchanger 21 acts as a condenser. This liquid refrigerant is decompressed and expanded by the expansion valve 20 to be gas-liquid two-phase mixed. This gas-liquid two-phase mixed refrigerant enters the heat exchanger 22 which is an outdoor heat exchanger, and evaporates into a gas by exchanging heat with the air sent by the outdoor fan. For this reason, the heat exchanger 22 acts as an evaporator. The gas refrigerant is sucked into the compressor 11 via the four-way valve 31, the heat exchanger 23, and the accumulator 13 and is compressed again by the compressor 11.

  In the heat pump system 3 of the present embodiment, similarly to the heat pump system 1, the compressor 11 that compresses the refrigerant, the oil separator 12 that separates the oil contained in the compressed refrigerant, and the oil separator 12 have an oil content. A first heat exchanger that dissipates the heat of the reduced refrigerant, an expansion valve 20 that is a decompression unit that lowers the pressure of the refrigerant dissipated by the first heat exchanger, and a second that causes the decompressed refrigerant to absorb heat. Heat exchanger which is a third heat exchanger that radiates the heat of oil separated by the oil separator 12 and sucked into the compressor 11 and heats the refrigerant absorbed by the second heat exchanger And an accumulator 13 that separates the liquid phase from the refrigerant heated by the heat exchanger 23 and causes the compressor 11 to suck the refrigerant after the liquid phase is separated. In the heat pump system 3 of the present embodiment, the oil radiated by the heat exchanger 23 is sucked into the compressor 11 together with the refrigerant after the liquid phase is separated by the accumulator 13. In the heat pump system 3, by having the four-way valve 31, the role of the first heat exchanger and the role of the second heat exchanger are allocated to the heat exchanger 21 and the heat exchanger 22, and the heat exchanger 21 and the heat exchanger The role with the exchanger 22 can be changed. Even if the roles of the heat exchanger 21 and the heat exchanger 22 are changed, the same effect as the heat pump system 1 described above can be obtained, and the oil can be circulated while keeping the refrigerant in the heated gas even if the load fluctuates rapidly.

  As described above, the heat pump system according to the present invention is suitable for circulating oil while keeping the refrigerant in the heated gas even when the load fluctuates rapidly.

1, 2, 3 Heat pump system 11 Compressor 12 Oil separator 13 Accumulator 14 Capillary 15A, 15B, 15C, 15D, 15E, 15F, 15G, 15H, 15I Refrigerant flow path 16A, 16B, 16C Oil flow path 17 Connection point 21, 22, 23 Heat exchanger 20 Expansion valve 31 Four-way valve 32a, 32b, 33c, 34d Flow path in four-way valve

Claims (2)

A compressor for compressing the refrigerant;
An oil separator for separating oil contained in the compressed refrigerant;
A first heat exchanger that dissipates heat of the refrigerant whose oil content is reduced by the oil separator;
A pressure reducing unit that reduces the pressure of the refrigerant radiated by the first heat exchanger;
A second heat exchanger that absorbs heat from the decompressed refrigerant;
A third heat exchanger that radiates heat of the oil separated by the oil separator and heats the refrigerant that has absorbed heat by the second heat exchanger;
An accumulator that separates a liquid phase from the refrigerant heated by the third heat exchanger, and sucks the refrigerant after the liquid phase is separated into the compressor;
The refrigerant flow path after the liquid phase is separated by the accumulator is connected to the flow path for sucking the oil radiated by the third heat exchanger into the compressor, and the third heat exchanger The heat pump system, wherein the radiated oil is sucked into the compressor together with the refrigerant after the liquid phase is separated by the accumulator. A temperature sensor for measuring the temperature of the refrigerant heated by the third heat exchanger;
A control device for determining the degree of superheat from the temperature of the refrigerant measured by the temperature sensor, and controlling the decompression unit according to the obtained degree of superheat;
The heat pump system according to claim 1, further comprising:

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