WO2016203624A1

WO2016203624A1 - Refrigeration cycle device

Info

Publication number: WO2016203624A1
Application number: PCT/JP2015/067652
Authority: WO
Inventors: 寛也石原; 智隆石川; 孝梅木
Original assignee: 三菱電機株式会社
Priority date: 2015-06-18
Filing date: 2015-06-18
Publication date: 2016-12-22
Also published as: EP3457049A1; EP3312524A4; JPWO2016203624A1; EP3457049B1; EP3312524B1; EP3312524A1; JP6735744B2

Abstract

A refrigeration cycle device is provided with a heat source-side unit, a load-side unit connected to the heat source-side unit via a first connection pipe and a second connection pipe, and a control device. A first compressor, a first heat source-side heat exchanger, a first heat source-side decompressor, a load-side decompressor, and a load-side heat exchanger constitute part of a first refrigeration cycle that is connected via a refrigerant pipeline and that circulates a first refrigerant. During a cooling operation in which the load-side heat exchanger functions as an evaporator, the control device adjusts the opening degree of the first heat source-side decompressor, and causes the first refrigerant to flow into the first connection pipeline as a liquid refrigerant having a pressure smaller than the design pressure of the first connection pipe.

Description

Refrigeration cycle equipment

The present invention relates to a refrigeration cycle apparatus that can use local piping.

As a conventional refrigeration cycle apparatus that can use local piping, for example, a refrigerant that flows from an outdoor unit to liquid piping that is local piping is decompressed by a flow control device into a gas-liquid two-phase state, thereby reducing the refrigerant cost. A refrigeration apparatus is known (for example, Patent Document 1).

JP 2012-112622 A

However, the refrigeration cycle apparatus of Patent Document 1 has a problem that the pressure loss and noise in the liquid pipe increase because the two-phase refrigerant flows through the liquid pipe.

The present invention has been made to solve the above-described problems, and an object thereof is to provide a refrigeration cycle apparatus capable of reducing pressure loss and noise in a liquid pipe.

The refrigeration cycle apparatus according to the present invention includes a heat source side unit that houses a first compressor, a first heat source side heat exchanger, and a first heat source side pressure reducing device, a load side pressure reducing device, and a load side heat. A first communication pipe that is disposed between the first heat source side pressure reducing device and the load side pressure reducing device, and the first compressor and the load side heat exchanger. A load side unit connected to the heat source side unit via a second connecting pipe disposed between the control unit and a load side unit; the first compressor; the first heat source side heat exchanger; The first heat source side decompression device, the load side decompression device, and the load side heat exchanger are connected via a refrigerant pipe, and constitute a first refrigeration cycle for circulating the first refrigerant, In the cooling operation in which the load side heat exchanger functions as an evaporator, the control device The opening degree of the first heat source side pressure reducing device is adjusted so that the first refrigerant flows into the first connecting pipe as a liquid refrigerant whose pressure is lower than the design pressure of the first connecting pipe. is there.

According to the present invention, the opening degree of the first heat source side pressure reducing device is adjusted, and the first refrigerant is supplied to the first communication pipe as a liquid refrigerant whose pressure is lower than the design pressure of the first communication pipe. Can flow in. Therefore, according to the present invention, since the refrigerant flowing into the first communication pipe can be used as the liquid refrigerant, it is possible to provide a refrigeration cycle apparatus capable of reducing pressure loss and noise in the first communication pipe. it can.

1 is a schematic refrigerant circuit diagram illustrating an example of a refrigeration cycle apparatus 1 according to Embodiment 1 of the present invention. It is a control block diagram expressing a part of control in the control apparatus 50 of the refrigerating cycle apparatus 1 which concerns on Embodiment 1 of this invention. It is a flowchart which shows an example of the control processing at the time of air_conditionaing | cooling operation in the control apparatus 50 of the refrigerating-cycle apparatus 1 which concerns on Embodiment 1 of this invention. It is a Mollier diagram which shows operation | movement of the refrigerating-cycle apparatus 1 which concerns on Embodiment 1 of this invention. It is a schematic refrigerant circuit diagram which shows an example of the refrigeration cycle apparatus 1 which concerns on Embodiment 2 of this invention. It is a control block diagram expressing a part of control in the control apparatus 50 of the refrigerating cycle apparatus 1 which concerns on Embodiment 2 of this invention. It is a flowchart which shows an example of the control processing at the time of air_conditionaing | cooling operation in the control apparatus 50 of the refrigerating-cycle apparatus 1 which concerns on Embodiment 2 of this invention. It is a Mollier diagram which shows operation | movement of the refrigerating-cycle apparatus 1 which concerns on Embodiment 2 of this invention. It is a schematic refrigerant circuit diagram which shows an example of the refrigeration cycle apparatus 1 which concerns on Embodiment 3 of this invention. It is a control block diagram expressing a part of control in the control apparatus 50 of the refrigerating cycle apparatus 1 which concerns on Embodiment 3 of this invention. It is a flowchart which shows an example of the control processing at the time of air_conditionaing | cooling operation in the control apparatus 50 of the refrigerating-cycle apparatus 1 which concerns on Embodiment 3 of this invention. It is a Mollier diagram which shows operation | movement of the refrigerating-cycle apparatus 1 which concerns on Embodiment 3 of this invention.

Embodiment 1 FIG.
A refrigeration cycle apparatus 1 according to Embodiment 1 of the present invention will be described. FIG. 1 is a schematic refrigerant circuit diagram illustrating an example of the refrigeration cycle apparatus 1 according to the first embodiment. In the following drawings including FIG. 1, the dimensional relationship and shape of each component may be different from the actual one.

As shown in FIG. 1, the refrigeration cycle apparatus 1 includes a heat source side unit 100 (for example, an outdoor unit) and a load side unit 200 (for example, an indoor unit) arranged in parallel to the heat source side unit 100. The heat source side unit 100 and the load side unit 200 are connected by a first connecting pipe 300 (liquid pipe) and a second connecting pipe 400 (gas pipe) which are local pipes. In addition, although the refrigerating-cycle apparatus 1 of FIG. 1 is set as the structure which connected one load side unit 200, it is good also as a structure which connected multiple load side units 200. FIG.

The refrigeration cycle apparatus 1 of the first embodiment includes a first compressor 2, a first heat source side heat exchanger 3, a first heat source side pressure reducing device 4, a load side pressure reducing device 5, and a load side. A heat exchanger 6 is connected via a refrigerant pipe, and a first refrigeration cycle 500 for circulating the first refrigerant is provided. Note that the first refrigerant circulating in the first refrigeration cycle 500 can be selected from any type of refrigerant according to the application of the refrigeration cycle apparatus 1. For example, in the refrigeration cycle apparatus 1 of Embodiment 1, a natural refrigerant such as CO ₂ , a hydrofluorocarbon such as R32, and a hydrofluorocarbon such as 2,3,3,3-tetrafluoro-1-propene (HFO-1234yf) A mixed solvent such as olefin and R410A can be used as the first refrigerant.

The first compressor 2 is a variable frequency fluid machine that is accommodated in the heat source side unit 100, compresses the sucked low-pressure first refrigerant, and discharges the compressed low-pressure first refrigerant. As the first compressor 2, for example, a scroll compressor whose rotation frequency is controlled by an inverter can be used.

The first heat source side heat exchanger 3 is a heat exchanger that functions as a radiator (condenser) in the first embodiment, and is housed in the heat source side unit 100. In the first embodiment, the first heat source side heat exchanger 3 includes a first refrigerant flowing inside the first heat source side heat exchanger 3 and a heat source side heat exchanger fan (not shown). It is comprised so that heat exchange with the external air (for example, outdoor air) ventilated may be performed. The first heat source side heat exchanger 3 is configured as, for example, a cross-fin type fin-and-tube heat exchanger including a heat transfer tube and a plurality of fins.

In the first embodiment, the first heat source side decompression device 4 expands and decompresses the high-pressure liquid refrigerant flowing from the first heat source side heat exchanger 3, and the first connection piping 300 which is a local piping. The first refrigerant having a pressure lower than the designed pressure is caused to flow into the first connecting pipe 300. For example, the design pressure of the first connecting pipe 300 is set to the pressure resistance reference value of the first connecting pipe 300. The first heat source side decompression device 4 is housed in the heat source side unit 100 and is configured as an electronic expansion valve such as a linear electronic expansion valve (LEV) whose opening degree can be adjusted in multiple stages or continuously.

In the first embodiment, the load-side decompression device 5 further expands and decompresses the first refrigerant having a pressure lower than the design pressure of the first communication pipe 300 flowing from the first communication pipe 300, It is made to flow into the exchanger 6. The load side decompression device 5 is accommodated in the load side unit 200, and is configured as an electronic expansion valve such as a linear electronic expansion valve whose opening degree can be adjusted in multiple stages or continuously.

The load-side heat exchanger 6 is a heat exchanger that functions as an evaporator (cooler) in the first embodiment, and is housed in the load-side unit 200. The load side heat exchanger 6 is configured to exchange heat between, for example, a refrigerant flowing inside the load side heat exchanger 6 and outside air (for example, indoor air). The load-side heat exchanger 6 can be configured as, for example, a cross-fin type fin-and-tube heat exchanger composed of a heat transfer tube and a plurality of fins. Moreover, you may comprise the load side heat exchanger 6 so that external air may be supplied with the ventilation from the fan for load side heat exchangers (not shown).

Hereinafter, the operation of the refrigeration cycle apparatus 1 in which the load-side heat exchanger 6 functions as an evaporator is referred to as “cooling operation”.

The refrigerant pipe housed in the heat source side unit 100 and disposed between the first heat source side pressure reducing device 4 and the first communication pipe 300 is connected to the first communication pipe 300. A heat source side connection valve 7a is provided. The heat source side refrigerant pipe accommodated in the heat source side unit 100 and disposed between the first compressor 2 and the second communication pipe 400 has a second heat source for connection to the second communication pipe 400. A side connection valve 7b is provided. The load side refrigerant pipe accommodated in the load side unit 200 and disposed between the load side pressure reducing device 5 and the first communication pipe 300 has a first load side for connection to the first communication pipe 300. A connection valve 8a is provided. The load-side refrigerant pipe accommodated in the load-side unit 200 and disposed between the load-side heat exchanger 6 and the second communication pipe 400 has a second load for connection to the second communication pipe 400. A side connection valve 8b is provided. The first heat source side connection valve 7a, the second heat source side connection valve 7b, the first load side connection valve 8a, and the second load side connection valve 8b are, for example, two-way capable of switching between open and closed It consists of a two-way valve such as a solenoid valve.

Next, the supercooling heat exchanger 10 and the second heat source side pressure reducing device 20 in the refrigeration cycle apparatus 1 of the first embodiment will be described.

The supercooling heat exchanger 10 is disposed between the first heat source side heat exchanger 3 and the first heat source side pressure reducing device 4. The supercooling heat exchanger 10 includes a first heat transfer tube 10 a and a second heat transfer tube 10 b and is accommodated in the heat source side unit 100. In the first embodiment, the supercooling heat exchanger 10 includes the first high-pressure refrigerant flowing through the first heat transfer tube 10a and the first reduced pressure flowing through the second heat transfer tube 10b during the cooling operation. It is a heat exchanger that exchanges heat with a refrigerant. The supercooling heat exchanger 10 can be configured as, for example, a cross fin type fin-and-tube heat exchanger including a first heat transfer tube 10a, a second heat transfer tube 10b, and a plurality of fins.

One end portion of the first heat transfer tube 10a and the first heat source side decompression device 4 are connected by a first heat source side refrigerant pipe 12. The other one end of the first heat transfer tube 10a and the first heat source side heat exchanger 3 are connected by a second heat source side refrigerant pipe 13. The branch connection portion 12 a disposed in the first heat source side refrigerant pipe 12 and one end portion of the second heat transfer pipe 10 b are connected by the first heat source side branch refrigerant pipe 16. The other one end of the second heat transfer tube 10b and the intermediate pressure portion of the first compressor 2 are connected by a second heat source side branched refrigerant pipe 18. Note that the first heat source side refrigerant pipe 12 and the second heat source side refrigerant pipe 13 are part of the refrigerant pipe constituting the first refrigeration cycle 500. Further, the first heat source side refrigerant pipe 12, the second heat source side refrigerant pipe 13, the first heat source side branch refrigerant pipe 16, and the second heat source side branch refrigerant pipe 18 are accommodated in the heat source side unit 100. Yes.

The second heat source side decompression device 20 is disposed in the first heat source side branch refrigerant pipe 16. The second heat source-side decompression device 20 expands and decompresses the high-pressure liquid refrigerant that branches from the first heat source-side refrigerant pipe 12 to the first heat source-side branch refrigerant pipe 16 and flows into the second heat transfer pipe 10b. It is what is made to flow into. The second heat source side pressure reducing device 20 is housed in the heat source side unit 100 and is configured as an electronic expansion valve such as a linear electronic expansion valve (LEV) whose opening degree can be adjusted in multiple stages or continuously.

Next, a sensor disposed in the refrigeration cycle apparatus 1 according to the first embodiment will be described.

The refrigeration cycle apparatus 1 according to the first embodiment includes a first temperature sensor 30, a second temperature sensor 35, a first pressure sensor 40, and a second pressure sensor 45.

The first temperature sensor 30 is disposed on the first heat source side refrigerant pipe 12 between the branch connection portion 12a and the first heat source side decompression device 4. The first temperature sensor 30 outputs the temperature of the first refrigerant flowing out from the first heat transfer tube 10a of the supercooling heat exchanger 10 and flowing into the first heat source side decompression device 4 during the cooling operation. It is the temperature sensor which detects via.

The second temperature sensor 35 is disposed in the second heat source side branch refrigerant pipe 18. The second temperature sensor 35 flows out of the second heat transfer tube 10b of the supercooling heat exchanger 10 during the cooling operation, and the temperature of the first refrigerant injected into the intermediate pressure portion of the first compressor 2. It is a temperature sensor which detects this through refrigerant piping.

As a material of the first temperature sensor 30 and the second temperature sensor 35, a semiconductor (for example, a thermistor) or a metal (for example, a resistance temperature detector) is used. Note that the first temperature sensor 30 and the second temperature sensor 35 may be made of the same material or different materials.

The first pressure sensor 40 is disposed in the second heat source side branched refrigerant pipe 18. The first pressure sensor 40 flows out from the second heat transfer tube 10b of the supercooling heat exchanger 10 during the cooling operation, and the pressure of the first refrigerant injected into the intermediate pressure portion of the first compressor 2. It is a pressure sensor that detects

The second pressure sensor 45 is housed in the load-side unit 200 and is disposed in a load-side refrigerant pipe disposed between the first load-side connection valve 8a and the load-side decompression device 5. The second pressure sensor 45 is a pressure sensor that detects the pressure of the first refrigerant flowing into the second pressure sensor 45 through the first communication pipe 300 during the cooling operation.

As the first pressure sensor 40 and the second pressure sensor 45, a crystal piezoelectric pressure sensor, a semiconductor sensor, a pressure transducer, or the like is used. The first pressure sensor 40 and the second pressure sensor 45 may be made of the same type or different types.

Next, the control device 50 according to the first embodiment will be described with reference to FIG. FIG. 2 is a control block diagram representing a part of control in the control device 50 of the refrigeration cycle apparatus 1 according to the first embodiment.

The control device 50 according to the first embodiment controls the first refrigeration cycle 500, and includes a microcomputer having a CPU, a memory (eg, ROM, RAM, etc.), an I / O port, and the like. ing. As shown in FIG. 2, the control device 50 according to the first embodiment is configured such that the control device 50 detects the electrical signal of the temperature information detected by the first temperature sensor 30 and the second temperature sensor 35, and the first An electrical signal of pressure information detected by the pressure sensor 40 and the second pressure sensor 45 is configured to be received. The control device 50 transmits a control signal corresponding to the electrical signal of temperature information and the electrical signal of pressure information to the first heat source side decompression device 4, the load side decompression device 5, and the second heat source side decompression device 20. . In the 1st heat source side decompression device 4, the opening degree of the 1st heat source side decompression device 4 is adjusted according to the transmitted control signal. In the load-side decompression device 5, the opening degree of the load-side decompression device 5 is adjusted according to the transmitted control signal. In the 2nd heat source side decompression device 20, the opening degree of the 2nd heat source side decompression device 20 is adjusted according to the transmitted control signal. In addition, the control device 50 can be configured to control other components of the first refrigeration cycle 500. For example, the control device 50 can be configured to be able to control the operation state such as the start and stop of the operation of the heat source side unit 100 and the load side unit 200 and the adjustment of the operation frequency of the first compressor 2.

The control device 50 is configured to have a storage unit (not shown) that can store various data such as the design pressure of the first communication pipe 300. Further, the control device 50 can be configured to have an interface unit (not shown) that can input various data such as the design pressure of the first communication pipe 300.

Next, the operation during the cooling operation of the refrigeration cycle apparatus 1 according to the first embodiment will be described.

The first refrigerant is discharged from the first compressor 2 as a high-temperature and high-pressure gas refrigerant and flows into the first heat source side heat exchanger 3. The high-temperature and high-pressure gas refrigerant flowing into the first heat source side heat exchanger 3 is heat-exchanged by releasing heat to a low-temperature medium such as outdoor air, and the first refrigerant becomes a high-pressure liquid refrigerant.

The high-pressure liquid refrigerant flows into the first heat transfer tube 10a of the supercooling heat exchanger 10 and is heat-exchanged with the first refrigerant flowing through the second heat transfer tube 10b to be supercooled. It becomes a supercooled high-pressure liquid refrigerant. In the refrigeration cycle apparatus 1 according to the first embodiment, the first refrigerant flowing through the second heat transfer tube 10b is divided by the branch connection portion 12a of the first heat source side refrigerant pipe 12, and the first heat source side branch. The liquid refrigerant or the two-phase refrigerant flows into the refrigerant pipe 16 and is expanded and depressurized by the second heat source side decompression device 20 (for example, medium pressure). The first refrigerant flowing out of the second heat transfer tube 10b is injected into the intermediate pressure portion of the first compressor 2 via the second heat source side branched refrigerant pipe 18.

The high-pressure liquid refrigerant supercooled by the supercooling heat exchanger 10 flows into the first heat source side decompression device 4 and is expanded and decompressed by the first heat source side decompression device 4, and the first refrigerant is A reduced-pressure (for example, medium pressure) liquid refrigerant or a two-phase refrigerant is obtained. The decompressed liquid refrigerant or two-phase refrigerant flows out of the heat source side unit 100 and flows into the load side unit 200 via the first connection pipe 300.

The decompressed liquid refrigerant or two-phase refrigerant that has flowed into the load-side unit 200 flows into the load-side decompressor 5. The decompressed liquid refrigerant or two-phase refrigerant that has flowed into the load-side decompression device 5 is further expanded and depressurized, and the first refrigerant becomes a low-temperature and low-pressure two-phase refrigerant. The low-temperature and low-pressure two-phase refrigerant flows into the load-side heat exchanger 6 and absorbs heat from a high-temperature medium such as indoor air, and the first refrigerant evaporates and has a high dryness or a low-temperature and low-pressure refrigerant. Gas refrigerant. The two-phase refrigerant having a high degree of dryness or the low-temperature and low-pressure gas refrigerant that has flowed out of the load-side heat exchanger 6 flows out of the load-side unit 200 and flows into the heat source-side unit 100 via the second connection pipe 400. . The two-phase refrigerant or the low-temperature low-pressure gas refrigerant having a high dryness flowing into the load-side unit 200 is sucked into the first compressor 2. The refrigerant sucked into the first compressor 2 is compressed, and the first refrigerant becomes a high-temperature and high-pressure gas refrigerant and is discharged from the first compressor 2. In the cooling operation of the refrigeration cycle apparatus 1, the above cycle is repeated.

Next, control processing in the control device 50 of the refrigeration cycle apparatus 1 according to Embodiment 1 will be described.

The control device 50 of the refrigeration cycle apparatus 1 according to the first embodiment adjusts the opening degree of the first heat source side decompression device 4 as a liquid refrigerant whose pressure is lower than the design pressure of the first communication pipe 300. The first refrigerant is configured to flow into the first communication pipe 300.

Further, the control device 50 of the refrigeration cycle apparatus 1 according to the first embodiment adjusts the opening degree of the second heat source side decompression device 20 during the cooling operation to increase the degree of supercooling, and thereby the first heat source. The temperature of the first refrigerant flowing into the side pressure reducing device 4 can be configured to be lower than the saturated liquid temperature of the first refrigerant at the design pressure.

In the following description of the control process of the first embodiment, it is assumed that the opening degree DH1 of the first heat source side decompression device 4 can be adjusted in the range of 0 ≦ DH ≦ 1. The state of the opening degree DH1 = 0 indicates that the first heat source side decompression device 4 is in the closed state, and the state of the opening degree DH1 = 1 indicates that the first heat source side decompression device 4 is in the fully open state. Indicates.

Further, the opening degree DH2 of the second heat source side decompression device 20 is adjustable in the range of 0 ≦ DH2 ≦ 1. The state of the opening degree DH2 = 0 indicates that the second heat source side decompression device 20 is closed, and the state of the opening degree DH2 = 1 indicates that the second heat source side decompression device 20 is fully open. Indicates.

FIG. 3 is a flowchart showing an example of a control process during cooling operation in the control device 50 of the refrigeration cycle apparatus 1 according to the first embodiment. The control process of FIG. 3 may be performed at all times during the cooling operation, or may be performed at any time when a change in the parameters of the refrigeration cycle apparatus 1 such as a change in the frequency of the first compressor 2 is detected. Also good.

In the first embodiment, it is assumed that data of the design pressure Pm (for example, pressure resistance reference value) of the first connecting pipe 300 is stored in the storage unit (not shown) of the control device 50. In addition, it is assumed that data relating to the Mollier diagram (Ph diagram) representing the state of the first refrigerant in the refrigeration cycle apparatus 1 is stored in the storage unit of the control device 50 as, for example, a table.

In step S11, the temperature Tc of the first refrigerant flowing into the first heat source side pressure reducing device 4 detected by the first temperature sensor 30 is equal to or higher than the saturated refrigerant temperature Ta of the first refrigerant at the design pressure Pm. It is determined in the control device 50 whether or not. The saturated liquid temperature Ta is a temperature value calculated by the control device 50 based on the value of the design pressure Pm.

When the temperature Tc of the first refrigerant is equal to or higher than the saturated liquid temperature Ta, in step S12, the control device 50 controls the opening degree DH2 of the second heat source side decompression device 20 to be opened by the adjustment value ΔDH2. Here, the adjustment value ΔDH2 is a constant that is arbitrarily determined in consideration of the specifications of the structure of the second heat source side decompression device 20, and the adjustment value ΔDH2 can be set to 0.02, for example. Thereafter, the control device 50 repeats the control process of step S12 until the temperature Tc of the first refrigerant becomes lower than the saturated liquid temperature Ta.

When the temperature Tc of the first refrigerant is lower than the saturated liquid temperature Ta, in Step S13, it is determined whether or not the pressure P of the first refrigerant flowing into the load side pressure reducing device 5 is equal to or lower than the saturated liquid pressure Ps. Determined at 50. Here, the pressure P of the first refrigerant flowing into the load-side decompression device 5 is detected by the second pressure sensor 45. The saturated liquid pressure Ps is a pressure value calculated by the control device 50 based on the value of the temperature Tc of the first refrigerant. On the Mollier diagram, the saturated liquid pressure Ps is changed from the temperature Tc of the first refrigerant by an equal enthalpy. Shown as a point on the saturated liquid line. When the pressure P of the first refrigerant is higher than the saturated liquid pressure Ps, the control process ends.

When the pressure P of the first refrigerant is equal to or lower than the saturated liquid pressure Ps, in step S14, the control device 50 controls the opening degree DH1 of the first heat source side decompression device 4 to be opened by the adjustment value ΔDH1. Here, the adjustment value ΔDH1 is a constant that is arbitrarily determined in consideration of the specifications of the structure and the like of the first heat source-side decompression device 4, and the adjustment value ΔDH1 can be set to 0.01, for example. Thereafter, the control device 50 repeats the control process of step S14 until the pressure P of the first refrigerant becomes higher than the saturated liquid pressure Ps.

Next, the effect of the present invention according to the first embodiment will be described.

As described above, the refrigeration cycle apparatus 1 according to the first embodiment includes the first compressor 2, the first heat source side heat exchanger 3, and the first heat source side decompression device 4. A first connecting pipe 300 that accommodates the unit 100, the load-side decompressor 5 and the load-side heat exchanger 6 and is disposed between the first heat source-side decompressor 4 and the load-side decompressor 5; A load side unit 200 connected to the heat source side unit 100 via a second communication pipe 400 disposed between the first compressor 2 and the load side heat exchanger 6, and a control device 50 are provided. The first compressor 2, the first heat source side heat exchanger 3, the first heat source side pressure reducing device 4, the load side pressure reducing device 5, and the load side heat exchanger 6 are connected via a refrigerant pipe, The first refrigeration cycle 500 that circulates the first refrigerant is configured, and the control device 50 includes a load During the cooling operation in which the heat exchanger 6 functions as an evaporator, the opening degree of the first heat source side decompression device 4 is adjusted, and the first refrigerant is a liquid refrigerant having a pressure lower than the design pressure of the first communication pipe 300. The refrigerant is caused to flow into the first connecting pipe 300.

As a conventional refrigeration device, for example, a two-way refrigeration device, the refrigerant amount and the product cost are reduced by reducing the total refrigerant amount of the refrigeration device by passing the two-phase refrigerant through the local liquid piping. Is generally known. In the conventional refrigeration system, in order to allow the two-phase refrigerant to pass through the local liquid piping, the outdoor unit is provided with a first expansion valve, and the refrigerant is decompressed and expanded to flow the two-phase refrigerant into the local liquid piping. . In the conventional refrigeration system, the indoor unit is provided with a second expansion valve, and the two-phase refrigerant flowing from the local liquid pipe is further depressurized and expanded to flow into the indoor heat exchanger functioning as an evaporator. Yes. As described above, the conventional refrigeration apparatus has a so-called two-stage throttle structure in which the first expansion valve and the second expansion valve are provided before and after the local liquid piping.

However, the conventional refrigeration system has a problem that the pressure loss and noise in the local piping increase because the two-phase refrigerant flows into the local liquid piping. In addition, when a plurality of indoor heat exchangers are installed (for example, when a plurality of indoor units are installed), the two-phase refrigerant flowing from the local liquid piping is not evenly distributed to the indoor heat exchangers. As the number of indoor heat exchangers increases, there is a problem that the distribution of the refrigerant deteriorates.

On the other hand, according to the configuration of the first embodiment, during the cooling operation, the opening degree of the first heat source side decompression device 4 is adjusted, and the pressure is less than the design pressure of the first communication pipe 300. As the refrigerant, the first refrigerant can flow into the first connecting pipe 300.

In the first embodiment, the refrigerant flowing into the first communication pipe 300 can be a liquid refrigerant, and the pressure loss and noise in the first communication pipe 300 can be reduced. Therefore, the refrigeration cycle apparatus 1 Energy consumption can be reduced. In addition, since the refrigerant flowing into the load side unit 200 from the first connecting pipe 300 becomes a liquid refrigerant, even when a plurality of load side heat exchangers 6 are installed in the refrigeration cycle apparatus 1, the refrigerant is evenly distributed. Can be distributed.

Moreover, in this Embodiment 1, since the pressure of the liquid refrigerant which flows into the 1st connection piping 300 can be made less than the design pressure of the 1st connection piping 300, the refrigeration cycle apparatus 1 which can divert the existing local piping Can provide. For example, the first communication pipe 300 may cause a pressure loss of the first refrigerant in a range where the saturation temperature of the refrigerant in the load side heat exchanger 6 does not fall below the evaporation temperature of the load side heat exchanger 6. Can be diverted.

Further, in the refrigeration cycle apparatus 1 according to the first embodiment, the heat source side unit 100 is disposed between the first heat source side heat exchanger 3 and the first heat source side decompression apparatus 4, and A first heat source side connecting the supercooling heat exchanger 10 having the heat transfer tube 10a and the second heat transfer tube 10b, and one end of the first heat transfer tube 10a and the first heat source side pressure reducing device 4. A refrigerant pipe 12, a second heat source side refrigerant pipe 13 connecting the other end of the first heat transfer pipe 10a and the first heat source side heat exchanger 3, and a first heat source side refrigerant pipe 12 The first heat source side branch refrigerant pipe 16 that connects the branch connection portion 12a arranged at the first end of the second heat transfer pipe 10b, and the other end of the second heat transfer pipe 10b. The second heat source side branch refrigerant pipe 18 connecting the intermediate pressure portion of the first compressor 2 and the first heat source side branch refrigerant distribution And a second heat source side pressure reducing device 20 disposed in the subcooling heat exchanger 10. The supercooling heat exchanger 10 includes a first refrigerant flowing through the first heat transfer tube 10 a and a second heat exchanger 10 during the cooling operation. Heat exchange is performed with the first refrigerant flowing through the heat transfer tube 10b, and the control device 50 adjusts the degree of subcooling by adjusting the opening of the second heat source side decompression device 20 during the cooling operation. The temperature of the first refrigerant flowing into the first heat source side decompression device 4 can be made lower than the saturated liquid temperature of the first refrigerant at the design pressure.

According to the above-described configuration, the temperature of the first refrigerant flowing into the first heat source side decompression device 4 can be made lower than the saturated liquid temperature of the first refrigerant at the design pressure. Even after decompression and expansion by the side decompression device 4, it is easy to maintain the first refrigerant in the liquid state.

FIG. 4 is a Mollier diagram showing the operation of the refrigeration cycle apparatus 1 according to the first embodiment. The vertical axis in the Mollier diagram of FIG. 4 is the absolute pressure (MPa), and the horizontal axis is the specific enthalpy (kJ / kg). FIG. 4 shows a saturated liquid line, a saturated vapor line, and each stroke in the first refrigeration cycle 500. For the sake of explanation, the first heat source side pressure reducing device 4 is located at a position corresponding to the expansion stroke. And the load side decompression device 5 is schematically shown. In addition, the Mollier diagram of FIG. 4 is a broken line that is a dashed-dotted line that is decompressed and expanded by the second heat source side decompression device 20 and heat-exchanged by the second heat transfer tube 10b of the supercooling heat exchanger 10. Shows the state.

Further, the point A on the Mollier diagram in FIG. 4 indicates the position of the saturated refrigerant temperature Ta of the first refrigerant calculated from the design pressure Pm. The point B on the Mollier diagram of FIG. 4 shows the position in the condensation step of the first refrigeration cycle 500 that has the same enthalpy as the point A. The point C on the Mollier diagram of FIG. 4 shows the position of the temperature Tc of the first refrigerant flowing into the first heat source side decompression device 4 in the condensation process of the first refrigeration cycle 500. The point D on the Mollier diagram of FIG. 4 shows the position in the expansion stroke of the first refrigeration cycle 500 at which the pressure is equal to the point C and the pressure is the design pressure Pm. The point E on the Mollier diagram of FIG. 4 shows the intersection of the straight line indicating the expansion stroke of the first refrigeration cycle 500 and the saturated liquid line, and the pressure of the first refrigerant is the saturated liquid pressure Ps. It is a position.

According to the above-described configuration, the first refrigerant flowing through the first heat transfer tube 10a and the second heat transfer tube are adjusted by the supercooling heat exchanger 10 by adjusting the opening degree of the second heat source side decompression device 20. Heat exchange can be performed with the first refrigerant flowing through 10b to increase the degree of supercooling. That is, according to the above-described configuration, the point C can be adjusted so as to be located on the left side of the point B in the Mollier diagram of FIG. The temperature of the first refrigerant at the point B is the same as or slightly higher than the saturated liquid temperature Ta at the point A. Therefore, when the point C is located on the left side of the point B, the first heat source side pressure reducing device 4 The temperature Tc of the first refrigerant flowing in is always lower than the saturated liquid temperature Ta.

Therefore, according to the above-described configuration, the first heat source side pressure reduction is performed so that the pressure P of the first refrigerant flowing into the first communication pipe 300 is larger than the saturated liquid pressure Ps and smaller than the design pressure Pm. It can be controlled by adjusting the opening of the device 4. In the Mollier diagram of FIG. 4, the state where the pressure P of the first refrigerant is larger than the saturated liquid pressure Ps and smaller than the design pressure Pm is the expansion stroke between the points D and E in FIG. 4. Corresponds to the position.

Specifically, when the design pressure of the first connecting pipe 300 (on-site pipe) is 1.64 MPa, the point A is 38 ° C., and when the condensation temperature is 50 ° C., the degree of supercooling is about 30 ° C. , Point C is 20 ° C. Therefore, in order to bring the refrigerant below the design pressure and in the liquid state in the first connection pipe 300, the first heat source side decompression device 4 may be controlled to 1.00 MPa to 1.64 MPa.

As described above, according to the configuration according to the first embodiment, the temperature Tc of the first refrigerant flowing into the first heat source side decompression device 4 is set to be lower than the saturated liquid temperature Ta, so that the first heat source side Even after decompression and expansion by the decompression device 4, the first refrigerant can maintain the liquid state.

Embodiment 2. FIG.
Embodiment 2 of the present invention is a modification of the refrigeration cycle apparatus 1 according to Embodiment 1 described above. FIG. 5 is a schematic refrigerant circuit diagram illustrating an example of the refrigeration cycle apparatus 1 according to the second embodiment.

The heat source side unit 100 of the refrigeration cycle apparatus 1 according to the second embodiment includes a second communication pipe 400 instead of the first heat source side branch refrigerant pipe 16 of the refrigeration cycle apparatus 1 according to the first embodiment described above. A third heat source side refrigerant pipe 14 connected between one end of the second heat transfer tube 10b of the supercooling heat exchanger 10 is provided. In addition, the heat source side unit 100 of the refrigeration cycle apparatus 1 according to the second embodiment is a supercooling heat exchanger instead of the second heat source side branch refrigerant pipe 18 of the refrigeration cycle apparatus 1 according to the first embodiment described above. And a fourth heat source side refrigerant pipe 15 connected between the other end of the ten second heat transfer tubes 10 b and the first compressor 2. Further, the heat source side unit 100 of the refrigeration cycle apparatus 1 of the second embodiment does not have the second heat source side decompression device 20. The second temperature sensor 35 and the first pressure sensor 40 are provided on the fourth heat source side refrigerant pipe 15 in the refrigeration cycle apparatus 1 of the second embodiment. The other structure of the heat source side unit 100 of the refrigeration cycle apparatus 1 according to the second embodiment is the same as that of the refrigeration cycle apparatus 1 according to the first embodiment.

FIG. 6 is a control block diagram representing a part of control in the control device 50 of the refrigeration cycle apparatus 1 according to the second embodiment. FIG. 6 is the same as the control block diagram of FIG. 2 except that the second heat source side pressure reducing device 20 is not provided.

Next, a control process in the control device 50 of the refrigeration cycle apparatus 1 according to the second embodiment will be described.

The control device 50 of the refrigeration cycle apparatus 1 according to Embodiment 2 adjusts the opening degree of the load-side decompression device to increase the degree of supercooling during the cooling operation, and increases the degree of supercooling to the first heat source-side decompression device. The temperature of the first refrigerant flowing in is configured to be lower than the saturated liquid temperature of the first refrigerant at the design pressure.

In the following description of the control process of the second embodiment, it is assumed that the opening degree DH1 of the first heat source side decompression device 4 can be adjusted in the range of 0 ≦ DH ≦ 1. The state of the opening degree DH1 = 0 indicates that the first heat source side decompression device 4 is in the closed state, and the state of the opening degree DH1 = 1 indicates that the first heat source side decompression device 4 is in the fully open state. Indicates.

Further, the opening DL of the load-side decompression device 5 is adjustable in the range of 0 ≦ DL ≦ 1. A state in which the opening degree DL = 0 indicates that the load-side decompression device 5 is in a closed state, and a state in which the opening degree DL = 1 indicates that the load-side decompression device 5 is in a fully open state.

FIG. 7 is a flowchart illustrating an example of a control process during cooling operation in the control device 50 of the refrigeration cycle apparatus 1 according to the second embodiment. The control process of FIG. 7 may be performed at all times during the cooling operation, similarly to the control process of FIG. You may make it carry out at any time when it detects.

Also in the second embodiment, data of the design pressure Pm (for example, withstand pressure reference value) of the first communication pipe 300 is stored in the storage unit (not shown) of the control device 50 as in the first embodiment. Is stored. In addition, it is assumed that data relating to the Mollier diagram (Ph diagram) representing the state of the first refrigerant in the refrigeration cycle apparatus 1 is stored in the storage unit of the control device 50 as, for example, a table.

In step S21, as in step S11 of the first embodiment described above, the temperature Tc of the first refrigerant flowing into the first heat source side decompression device 4 detected by the first temperature sensor 30 is the design pressure. The controller 50 determines whether or not the temperature is equal to or higher than the saturated refrigerant temperature Ta of the first refrigerant at Pm.

When the temperature Tc of the first refrigerant is equal to or higher than the saturated liquid temperature Ta, the controller 50 controls the opening DL of the load-side decompressor 5 to be opened by the adjustment value ΔDL in step S22. Here, the adjustment value ΔDL is a constant arbitrarily determined in consideration of the specifications of the structure and the like of the load-side decompression device 5, and the adjustment value ΔDH2 can be set to 0.02, for example. Thereafter, the control device 50 repeats the control process of step S22 until the temperature Tc of the first refrigerant becomes lower than the saturated liquid temperature Ta.

In step S23, as in step S13 of the first embodiment, when the temperature Tc of the first refrigerant is lower than the saturated liquid temperature Ta, the pressure P of the first refrigerant flowing into the load-side decompression device 5 is It is determined in the control device 50 whether or not it is equal to or lower than the saturated liquid pressure Ps. When the pressure P of the first refrigerant is higher than the saturated liquid pressure Ps, the control process ends.

In step S24, as in step S14 of the first embodiment described above, when the pressure P of the first refrigerant is equal to or lower than the saturated liquid pressure Ps, the control device 50 opens the first heat source side decompression device 4. The degree DH1 is controlled to be opened by the adjustment value ΔDH1.

The heat source side unit 100 of the refrigeration cycle apparatus 1 according to the second embodiment is disposed between the first heat source side heat exchanger 3 and the first heat source side pressure reducing device 4, and includes the first heat transfer tube 10a and the first heat transfer tube 10a. A subcooling heat exchanger 10 having two heat transfer tubes 10b, a first heat source side refrigerant pipe 12 connecting one end of the first heat transfer tube 10a and the first heat source side decompression device 4, A second heat source side refrigerant pipe 13 connecting the other end of the first heat transfer pipe 10a and the first heat source side heat exchanger 3, a second communication pipe 400, and a second heat transfer pipe 10b. A third heat source side refrigerant pipe 14 connected between one end of the second heat transfer pipe 10b and a fourth compressor connected between the other end of the second heat transfer pipe 10b and the first compressor 2. The supercooling heat exchanger 10 further includes a heat source side refrigerant pipe 15 and the first cooling pipe 10a that flows through the first heat transfer pipe 10a during the cooling operation. And the first refrigerant flowing through the second heat transfer tube 10b, and the control device 50 adjusts the opening degree of the load-side decompression device 5 during the cooling operation. The degree of cooling is increased, and the temperature of the first refrigerant flowing into the first heat source side decompression device 4 is made lower than the saturated liquid temperature of the first refrigerant at the design pressure.

FIG. 8 is a Mollier diagram showing the operation of the refrigeration cycle apparatus 1 according to the second embodiment. FIG. 8 is the same as the Mollier diagram of FIG. 4 except that the broken line indicating the state of the refrigerant heat-exchanged in the second heat transfer tube 10b of the supercooling heat exchanger 10 is not described. is there.

According to the configuration of the second embodiment, the opening degree of the load-side decompression device 5 is adjusted, and the first refrigerant that flows through the first heat transfer tube 10a and the second transfer in the supercooling heat exchanger 10 are obtained. Heat exchange can be performed with the first refrigerant flowing through the heat pipe 10b to increase the degree of supercooling. Further, by setting the temperature Tc of the first refrigerant flowing into the first heat source side decompression device 4 to be lower than the saturated liquid temperature Ta, the first refrigerant after decompression and expansion by the first heat source side decompression device 4 is also achieved. Can maintain a liquid state.

Further, according to the configuration of the second embodiment, the two-phase refrigerant or the low-temperature and low-pressure gas refrigerant that has flowed out of the load-side heat exchanger 6 is further superheated in the supercooling heat exchanger 10, so that the first Liquid return to the compressor 2 of 1 can be avoided. Therefore, according to the configuration of the second embodiment, the reliability of the refrigeration cycle apparatus 1 can be improved. Further, according to the configuration of the second embodiment, since all the first refrigerants flowing through the refrigeration cycle apparatus 1 can be used for heat exchange in the load side heat exchanger 6, the cooling capacity of the refrigeration cycle apparatus 1 Can be improved.

Embodiment 3 FIG.
In the third embodiment of the present invention, the refrigeration cycle apparatus 1 of the first embodiment described above further includes a second refrigeration cycle 600. FIG. 9 is a schematic refrigerant circuit diagram illustrating an example of the refrigeration cycle apparatus 1 according to the third embodiment.

In the refrigeration cycle apparatus 1 of the third embodiment, in addition to the configuration of the first embodiment, the heat source side unit 100 includes a second compressor 62, a second heat source side heat exchanger 63, and a third The heat source side pressure reducing device 64 and the first heat source side heat exchanger 3 are connected via a refrigerant pipe, and further provided with a second refrigeration cycle 600 for circulating the second refrigerant, and the first heat source The side heat exchanger 3 exchanges heat between the first refrigerant flowing from the first compressor 2 and the second refrigerant flowing from the third heat source side decompression device 64 during the cooling operation. The second heat source side heat exchanger functions as a radiator.

The structure and operation of the second compressor 62, the second heat source side heat exchanger 63, and the third heat source side pressure reducing device 64 in the second refrigeration cycle 600 are the same as those of the first compressor 2, the first heat source. It is the same as the side heat exchanger 3 and the first heat source side decompression device 4. In the third embodiment, as described above, the first heat source side heat exchanger 3 includes the first refrigerant flowing from the first compressor 2 and the third heat source side decompression during the cooling operation. It functions as a cascade heat exchanger that performs heat exchange with the second refrigerant flowing in from the device 64.

In the second refrigeration cycle 600 of Embodiment 3, for example, hydrofluorocarbons such as R32, hydrofluoroolefins such as 2,3,3,3-tetrafluoro-1-propene (HFO-1234yf), R410A and the like A mixed solvent can be used as the second refrigerant.

FIG. 10 is a control block diagram representing a part of control in the control device 50 of the refrigeration cycle apparatus 1 according to the third embodiment. FIG. 10 is the same as the control block diagram of FIG. 2 except that the opening degree of the third heat source side decompression device 64 is controlled by the control device 50.

FIG. 11 is a flowchart illustrating an example of a control process during cooling operation in the control device 50 of the refrigeration cycle apparatus 1 according to the third embodiment. The control process of FIG. 11 is the same as the control process of FIG. 3, and steps S31 to S34 of FIG. 11 correspond to S11 to S14 of FIG. The contents of other control processes are the same as the control processes of the first embodiment.

FIG. 12 is a Mollier diagram showing the operation of the refrigeration cycle apparatus 1 according to the third embodiment. FIG. 12 is the same as the Mollier diagram of FIG.

Also in the configuration of the third embodiment, the opening degree of the second heat source side decompression device 20 is adjusted and the supercooling heat exchanger 10 is used to adjust the first heat transfer tube 10a as in the first embodiment. Heat exchange can be performed between the first refrigerant flowing through the first refrigerant and the first refrigerant flowing through the second heat transfer tube 10b to increase the degree of supercooling. Further, by setting the temperature Tc of the first refrigerant flowing into the first heat source side decompression device 4 to be lower than the saturated liquid temperature Ta, the first refrigerant after decompression and expansion by the first heat source side decompression device 4 is also achieved. Can maintain a liquid state.

Further, the configuration of the third embodiment, using CO ₂ as the first refrigerant, for the CO ₂ can be used in the following supercritical state can provide a refrigeration cycle device 1 with excellent safety.

Other embodiments.
The present invention is not limited to the above-described embodiment, and various modifications can be made. For example, the refrigeration cycle apparatus 1 of the above-described embodiment can be used for an air conditioner, a refrigerator, and the like, for example.

Further, when the refrigeration cycle apparatus 1 is used as an air conditioner, it can be configured to perform a heating operation. For example, a refrigerant flow switching device (for example, a four-way valve) can be provided in the refrigeration cycle device 1 so that the cooling operation and the heating operation can be switched.

Moreover, the opening degree of the 2nd heat-source side decompression device 20 or the load side decompression device 5 is adjusted using the 2nd temperature sensor 35 and the 1st pressure sensor 40 in the above-mentioned embodiment, and the 1st It is possible to control so that the amount of liquid returned to the compressor 2 is suppressed.

Further, the above-described embodiments can be used in combination with each other.

1 Refrigeration cycle device, 2nd compressor, 1st heat source side heat exchanger, 4th heat source side decompression device, 5 load side decompression device, 6 load side heat exchanger, 7a 1st heat source side Connection valve, 7b Second heat source side connection valve, 8a First load side connection valve, 8b Second load side connection valve, 10 Subcooling heat exchanger, 10a First heat transfer tube, 10b Second heat transfer tube , 12 1st heat source side refrigerant pipe, 12a branch connection part, 13 2nd heat source side refrigerant pipe, 14 3rd heat source side refrigerant pipe, 15 4th heat source side refrigerant pipe, 16 1st heat source side branch refrigerant Piping, 18 second heat source side branch refrigerant piping, 20 second heat source side pressure reducing device, 30 first temperature sensor, 35 second temperature sensor, 40 first pressure sensor, 45 second pressure sensor, 50 Control device, 62 2nd Compressor, 63 3rd heat source side heat exchanger, 64 3rd heat source side pressure reducing device, 100 Heat source side unit, 200 Load side unit, 300 1st connecting pipe, 400 2nd connecting pipe, 500 1st Refrigeration cycle, 600 second refrigeration cycle.

Claims

A heat source side unit that houses a first compressor, a first heat source side heat exchanger, and a first heat source side pressure reducing device;
A first communication pipe that houses a load-side decompression device and a load-side heat exchanger, and is disposed between the first heat source-side decompression device and the load-side decompression device; and the first compressor; A load side unit connected to the heat source side unit via a second connecting pipe disposed between the load side heat exchanger;
A control device,
The first compressor, the first heat source side heat exchanger, the first heat source side pressure reducing device, the load side pressure reducing device, and the load side heat exchanger are connected via a refrigerant pipe, Constituting a first refrigeration cycle for circulating one refrigerant,
The controller is
At the time of cooling operation in which the load side heat exchanger functions as an evaporator, the opening degree of the first heat source side pressure reducing device is adjusted, and the pressure is less than the design pressure of the first communication pipe, A refrigeration cycle apparatus for causing the first refrigerant to flow into the first communication pipe.
The heat source side unit is:
A subcooling heat exchanger disposed between the first heat source side heat exchanger and the first heat source side pressure reducing device and having a first heat transfer tube and a second heat transfer tube;
A first heat source side refrigerant pipe connecting one end of the first heat transfer tube and the first heat source side pressure reducing device;
A second heat source side refrigerant pipe connecting the other one end of the first heat transfer tube and the first heat source side heat exchanger;
A first heat source side branch refrigerant pipe connecting the branch connection portion arranged in the first heat source side refrigerant pipe and one end of the second heat transfer pipe;
A second heat source side branched refrigerant pipe connecting the other one end of the second heat transfer pipe and the intermediate pressure portion of the first compressor;
A second heat source side decompression device disposed in the first heat source side branch refrigerant pipe,
The supercooling heat exchanger is
During the cooling operation, heat exchange is performed between the first refrigerant flowing through the first heat transfer tube and the first refrigerant flowing through the second heat transfer tube,
The controller is
During the cooling operation, the degree of supercooling is increased by adjusting the opening degree of the second heat source side decompression device, and the temperature of the first refrigerant flowing into the first heat source side decompression device is set to the design. The refrigeration cycle apparatus according to claim 1, wherein the refrigeration cycle apparatus is lower than a saturated liquid temperature of the first refrigerant at a pressure.
The heat source side unit is:
A subcooling heat exchanger disposed between the first heat source side heat exchanger and the first heat source side pressure reducing device and having a first heat transfer tube and a second heat transfer tube;
A first heat source side refrigerant pipe connecting one end of the first heat transfer tube and the first heat source side pressure reducing device;
A second heat source side refrigerant pipe connecting the other one end of the first heat transfer tube and the first heat source side heat exchanger;
A third heat source side refrigerant pipe connected between the second communication pipe and one end of the second heat transfer pipe;
A fourth heat source side refrigerant pipe connected between the other end of the second heat transfer tube and the first compressor;
The supercooling heat exchanger is
During the cooling operation, heat exchange is performed between the first refrigerant flowing through the first heat transfer tube and the first refrigerant flowing through the second heat transfer tube,
The controller is
During the cooling operation, the degree of supercooling is increased by adjusting the opening of the load-side decompression device, and the temperature of the first refrigerant flowing into the first heat source-side decompression device is set at the design pressure. The refrigeration cycle apparatus according to claim 1, wherein the temperature is lower than a saturated liquid temperature of the first refrigerant.
The refrigeration cycle apparatus according to any one of claims 1 to 3, wherein the first refrigerant is CO 2 .
The heat source unit is
A second compressor, a second heat source side heat exchanger, a third heat source side pressure reducing device, and the first heat source side heat exchanger are connected via a refrigerant pipe, and the second refrigerant is supplied. A second refrigeration cycle for circulation;
The first heat source side heat exchanger is:
During the cooling operation, heat exchange is performed between the first refrigerant flowing in from the first compressor and the second refrigerant flowing in from the third heat source side decompression device,
The second heat source side heat exchanger is:
The refrigeration cycle apparatus according to any one of claims 1 to 4, wherein the refrigeration cycle apparatus functions as a radiator during the cooling operation.