WO2020208752A1

WO2020208752A1 - Outdoor unit, refrigeration cycle device, and refrigerating machine

Info

Publication number: WO2020208752A1
Application number: PCT/JP2019/015681
Authority: WO
Inventors: 智隆石川; 悠介有井; 素早坂
Original assignee: 三菱電機株式会社
Priority date: 2019-04-10
Filing date: 2019-04-10
Publication date: 2020-10-15
Also published as: CN113692517B; JPWO2020208752A1; EP3954947A1; JP7150148B2; EP3954947B1; EP3954947A4; CN113692517A

Abstract

An outdoor unit (2) comprises: a compressor (10); a condenser (20); a heat exchanger (30) that exchanges heat between a refrigerant flowing through a first passage (H1) and a refrigerant flowing through a second passage (H2); and a second expansion valve (40). The outdoor unit (2) further comprises: a first refrigerant flow passage (91-94) that causes the refrigerant to flow from the portion of a circulation flow passage between the outlet of the first passage (H1) and the second expansion valve (40) to the inlet of the second passage (H2); a second refrigerant flow passage (96-98) that causes the refrigerant to flow from the outlet of the second passage (H2) to the inlet port (G1) or intermediate pressure port (G3) of the compressor (10); and a flow path switching unit (74) that is disposed in the second refrigerant flow path and switches the destination of the refrigerant flowing out of the outlet of the second passage (H2) to either the suction port (G1) or the intermediate pressure port (G3).

Description

Outdoor unit, refrigeration cycle device and refrigerator

The present invention relates to an outdoor unit, a refrigeration cycle device and a refrigerator.

Japanese Patent Application Laid-Open No. 2017-187189 (Patent Document 1) prevents the temperature of the refrigerant discharged from the compressor from becoming excessively high by controlling the torque of the motor built in the compressor. Refrigeration equipment is disclosed.

JP-A-2017-187189

In recent years, natural refrigerants such as CO ₂ have been attracting attention as refrigerants. Since the critical temperature of CO ₂ is as low as 31 ° C., the condensation process of the refrigeration cycle apparatus using CO ₂ is performed in a supercritical pressure state in summer when the outside air is high. Therefore, there is a problem that the entire system becomes high pressure. Designing the entire system to withstand high pressures is more costly than traditional or alternative CFC systems. In order to reduce costs, it is desirable that the conventionally used device can be used as it is with the load device alone.

However, if the design pressure of the load device is lowered, it is necessary to reduce the pressure in advance with an expansion valve in the liquid pipe that sends the liquid refrigerant from the outdoor unit to the load device. At this time, if a gas refrigerant is mixed in the liquid refrigerant in front of the expansion valve of the load device, the flow rate of the expansion valve is significantly reduced, so that a sufficient degree of supercooling (SC: Subcool) is secured to avoid a decrease in capacity. is necessary.

In addition, in order to improve performance, it is conceivable to install an internal heat exchanger to increase the degree of supercooling and adopt an intermediate pressure injection circuit that returns the refrigerant on the cooling side to the intermediate pressure port of the compressor, but the evaporation temperature is high. In some cases, the intermediate pressure is also high, so it is difficult to secure the degree of supercooling with the internal heat exchanger. Therefore, the capacity of the refrigeration cycle device may be reduced.

An object of the present invention is to provide an outdoor unit, a refrigerating cycle device, and a refrigerator capable of ensuring the degree of supercooling of the refrigerant at the inlet portion of the load device even when the evaporation temperature is high.

The outdoor unit of the present disclosure is an outdoor unit of a refrigeration cycle device configured to be connected to a load device including a first expansion valve and an evaporator. The outdoor unit includes a compressor having a suction port, a discharge port, and an intermediate pressure port, a condenser, a heat exchanger, and a second expansion valve. The heat exchanger has a first passage and a second passage, and is configured to exchange heat between the refrigerant flowing through the first passage and the refrigerant flowing through the second passage. The flow path from the compressor to the condenser, the first passage of the heat exchanger, and the second expansion valve forms a circulation flow path through which the refrigerant circulates together with the load device. The outdoor unit is arranged in the first refrigerant flow path and the first refrigerant flow path, in which the refrigerant flows from the portion between the outlet of the first passage and the second expansion valve of the circulation flow path to the inlet of the second passage. A third expansion valve, a second refrigerant flow path that allows refrigerant to flow from the outlet of the second passage to the suction port or intermediate pressure port of the compressor, and a refrigerant that is arranged in the second refrigerant flow path and flows out from the outlet of the first passage. It is further provided with a flow path switching unit that switches the destination to either the suction port or the intermediate pressure port.

According to the outdoor unit of the present disclosure and the refrigerating cycle device and the refrigerator provided therewith, the degree of supercooling of the liquid refrigerant sent from the outdoor unit to the load device can be ensured even when the evaporation temperature changes, so that the refrigerating capacity is reduced. Can be prevented.

It is an overall block diagram of the refrigeration cycle apparatus according to Embodiment 1 of this disclosure. It is a flowchart for demonstrating the control of the flow path switching part 74. It is a flowchart for demonstrating the control of the 3rd expansion valve 71. It is a flowchart for demonstrating the control of the 4th expansion valve 72. It is a flowchart for demonstrating control of 2nd expansion valve 40.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Hereinafter, a plurality of embodiments will be described, but it is planned from the beginning of the application that the configurations described in each embodiment are appropriately combined. The same or corresponding parts in the drawings are designated by the same reference numerals, and the description thereof will not be repeated.

FIG. 1 is an overall configuration diagram of a refrigeration cycle apparatus according to the embodiment of the present disclosure. It should be noted that FIG. 1 functionally shows the connection relationship and the arrangement configuration of each device in the refrigeration cycle apparatus, and does not necessarily show the arrangement in the physical space.

With reference to FIG. 1, the refrigeration cycle device 1 includes an outdoor unit 2, a load device 3, and

extension pipes

84 and 88.

The outdoor unit 2 is an outdoor unit of the refrigeration cycle device 1 configured to be connected to the load device 3. The outdoor unit 2 includes a compressor 10 having a suction port G1, a discharge port G2, and an intermediate pressure port G3, a condenser 20, a fan 22, a heat exchanger 30, a second expansion valve 40, and pipes 80 to 83. , 89 and. The heat exchanger 30 has a first passage H1 and a second passage H2, and is configured to exchange heat between the refrigerant flowing through the first passage H1 and the refrigerant flowing through the second passage H2.

The load device 3 includes a first expansion valve 50, an evaporator 60, and

pipes

85, 86, 87. The first expansion valve 50 is, for example, a temperature expansion valve that is controlled independently of the outdoor unit 2.

The compressor 10 compresses the refrigerant sucked from the

pipes

89 and 97 and discharges it to the pipe 80. The compressor 10 is configured to adjust the rotation speed according to a control signal from the control device 100. By adjusting the rotation speed of the compressor 10, the circulation amount of the refrigerant is adjusted, and the capacity of the refrigeration cycle device 1 can be adjusted. Various types of compressors 10 can be adopted, and for example, scroll type, rotary type, screw type and the like can be adopted.

The condenser 20 condenses the refrigerant discharged from the compressor 10 to the pipe 80 and flows it to the pipe 81. The condenser 20 is configured such that a high-temperature and high-pressure gas refrigerant discharged from the compressor 10 exchanges heat (heat dissipation) with the outside air. By this heat exchange, the refrigerant is condensed and changed to a liquid phase. The fan 22 supplies the condenser 20 with outside air through which the refrigerant exchanges heat in the condenser 20. By adjusting the rotation speed of the fan 22, the refrigerant pressure (high pressure side pressure) on the discharge side of the compressor 10 can be adjusted.

In this specification, for the sake of simplicity, the condenser 20 is also referred to when cooling the refrigerant in the supercritical state. Further, in the present specification, for the sake of simplicity, the amount of decrease of the refrigerant in the supercritical state from the reference temperature is also referred to as the degree of supercooling.

The flow path from the compressor 10 to the condenser 20, the first passage H1 of the heat exchanger 30, and the second expansion valve 40 is together with the flow path in which the first expansion valve 50 and the evaporator 60 of the load device 3 are arranged. , Form a circulation flow path through which the refrigerant circulates. Hereinafter, this circulation flow path is also referred to as a "main circuit" of the refrigeration cycle.

The outdoor unit 2 includes a first refrigerant flow path (91 to 94) in which a refrigerant flows from a portion between the outlet of the first passage H1 and the second expansion valve 40 of the circulation flow path to the inlet of the second passage H2. A second refrigerant flow path (96 to 98) for flowing a refrigerant from the outlet of the second passage H2 to the suction port G1 or the intermediate pressure port G3 of the compressor 10, and an outlet of the second passage H2 arranged in the second refrigerant flow path. Further, a flow path switching unit 74 for switching the destination of the refrigerant flowing out from the suction port G1 or the intermediate pressure port G3 is provided. In the following, this flow path that branches from the main circuit and sends the refrigerant to the compressor 10 via the second passage H2 is referred to as an “injection flow path”.

The outdoor unit 2 is further arranged in the first refrigerant flow path, and is a portion between the receiver (receiver) 73 for storing the refrigerant and the outlet of the first passage H1 of the circulation flow path and the second expansion valve 40. The third expansion valve 71 arranged in the pipe 91 between the receiver 73 and the inlet of the receiver 73, and the liquid receiver provided between the outlet pipe 94 of the receiver 73 and the gas discharge port of the receiver 73. A gas vent passage 93 for discharging the refrigerant gas in the vessel 73 and a fourth expansion valve 72 arranged in the gas vent passage 93 are provided.

By providing the liquid receiver 73 in the injection flow path in this way, it becomes easy to secure the degree of supercooling in the

pipes

82 and 83 which are liquid pipes. This is because the receiver 73 generally has a gas refrigerant, so that the refrigerant temperature becomes a saturation temperature. Therefore, if the receiver 73 is arranged in the pipe 82, the degree of supercooling cannot be ensured.

Further, if the receiver 73 is provided in the intermediate pressure portion, the intermediate pressure liquid refrigerant can be stored inside the receiver 73 even when the high pressure portion of the main circuit is in the supercritical state. Therefore, the design pressure of the container of the receiver 73 can be made lower than that of the high pressure portion, and the cost can be reduced by thinning the container.

The outdoor unit 2 further includes

pressure sensors

110, 111, 112,

temperature sensors

120, 121, 122, and a control device 100 that controls the flow path switching unit 74.

The pressure sensor 110 detects the suction pressure PL of the compressor 10 and outputs the detected value to the control device 100. The pressure sensor 111 detects the discharge pressure PH of the compressor 10 and outputs the detected value to the control device 100. The pressure sensor 112 detects the pressure P1 of the pipe 83 at the outlet of the second expansion valve 40, and outputs the detected value to the control device 100.

By equipping the liquid pipe with the second expansion valve 40, the outdoor unit 2 can reduce the refrigerant pressure to or less than the design pressure of the load device 3 (for example, 4 MPa) before sending it to the load device 3. As a result, even if a refrigerant that utilizes supercritical fluid such as CO2 is used, a general-purpose product having the same design pressure as the conventional one can be used as the load device 3.

The temperature sensor 120 detects the discharge temperature TH of the compressor 10 and outputs the detected value to the control device 100. The temperature sensor 121 detects the refrigerant temperature T1 of the pipe 81 at the outlet of the condenser 20, and outputs the detected value to the control device 100. The temperature sensor 122 detects the refrigerant temperature T2 at the outlet of the first passage H1 on the cooled side of the heat exchanger 30, and outputs the detected value to the control device 100.

The second refrigerant flow path includes a pipe 96 that connects the outlet of the second passage H2 of the heat exchanger 30 and the flow path switching portion 74, and the flow path switching portion 74. The flow path switching unit 74 includes

pipes

97 and 98 in which the pipe 96 is branched into two, and on-off

valves

75 and 76 arranged in the

pipes

97 and 98, respectively. The pipe 97 is connected between the pipe 96 and the intermediate pressure port G3. The pipe 98 is connected between the pipe 96 and the suction port G1. By selectively opening one of the on-off

valves

75 and 76, the destination of the refrigerant flowing through the injection flow path can be switched.

The control device 100 includes a CPU (Central Processing Unit) 102, a memory 104 (ROM (Read Only Memory) and RAM (Random Access Memory)), an input / output buffer (not shown) for inputting / outputting various signals, and the like. Consists of including. The CPU 102 expands the program stored in the ROM into a RAM or the like and executes the program. The program stored in the ROM is a program in which the processing procedure of the control device 100 is described. The control device 100 executes control of each device in the outdoor unit 2 according to these programs. This control is not limited to software processing, but can also be processed by dedicated hardware (electronic circuit).

FIG. 2 is a flowchart for explaining the control of the flow path switching unit 74. With reference to FIGS. 1 and 2, the control device 100 determines in step S1 whether the on-off valve 75 is in the open state and the on-off valve 76 is in the closed state. If the on-off valve 75 is in the open state and the on-off valve 76 is in the closed state (YES in S1), the intermediate pressure port G3 is selected as the destination of the refrigerant flowing through the injection flow path. On the contrary, when the suction port G1 is selected as the destination of the refrigerant flowing through the injection flow path, the on-off valve 75 is in the closed state and the on-off valve 76 is in the open state.

When the on-off valve 75 is in the open state (YES in S1), in step S2, the control device 100 determines whether or not the refrigerant temperature T2 at the outlet of the first passage H1 of the heat exchanger 30 is equal to or higher than the first temperature Tth1. To judge.

When the refrigerant temperature T2 at the outlet of the first passage H1 of the heat exchanger 30 is higher than the first temperature Tth1 (YES in S2), the control device 100 sucks the destination of the refrigerant in the processes of steps S3 to S7. The flow path switching unit 74 is controlled so as to be the port G1. Even when the refrigerant temperature T2 at the outlet of the first passage H1 of the heat exchanger 30 = the first temperature Tth1 (YES in S2), the control device 100 sets the destination of the refrigerant to the suction port G1 in the processes of steps S3 to S7. The flow path switching unit 74 is controlled so as to.

Specifically, when the intake air temperature TL of the compressor 10 is equal to or higher than the threshold value TLth1 (YES in S3), the control device 100 sequentially executes the processes of steps S4 to S7 to set the destination of the refrigerant to the suction port G1. The flow path switching unit 74 is controlled so as to. The intake air temperature TL of the compressor 10 can be obtained by converting from the intake pressure PL detected by the pressure sensor 110. The operation of the compressor 10 is stopped in step S4, the on-off valve 75 is closed in step S5, the on-off valve 76 is opened in step S6, and the operation of the compressor 10 is restarted in step S7.

When the refrigerant temperature T2 is lower than the first temperature Tth1 (NO in S2), the degree of supercooling can be secured, and when the intake air temperature TL of the compressor 10 is lower than the threshold value TLth1 (NO in S3). ), Since the evaporation temperature is low, the intermediate pressure is also low, so that the control device 100 does not switch the flow path switching unit 74 in steps S4 to S7.

On the other hand, when the on-off valve 75 is in the closed state (NO in S1) and the refrigerant temperature T2 at the outlet of the first passage H1 of the heat exchanger 30 is lower than the second temperature Tth2 (YES in S8), In the processes of steps S9 to S13, the control device 100 controls the flow path switching unit 74 so that the destination of the refrigerant is the intermediate pressure port G3. Even when the refrigerant temperature T2 = the second temperature Tth2 (YES in S2), the control device 100 controls the flow path switching unit 74 so that the destination of the refrigerant is the intermediate pressure port G3. In addition, Tth1> Tth2.

Specifically, when the intake air temperature TL of the compressor 10 is equal to or less than the threshold value TLth1 (YES in S9), the control device 100 sequentially executes the processes of steps S10 to S13 to set the destination of the refrigerant to the intermediate pressure port. The flow path switching unit 74 is controlled so as to be G3. In addition, TLth1> TLth2. The operation of the compressor 10 is stopped in step S10, the on-off valve 76 is closed in step S11, the on-off valve 75 is opened in step S12, and the operation of the compressor 10 is restarted in step S13.

When the refrigerant temperature T2 is higher than the second temperature Tth2 (NO in S8), the degree of supercooling cannot be secured, and when the intake air temperature TL of the compressor 10 is higher than the threshold value TLth2 (in S9). In NO), since the evaporation temperature is high, the intermediate pressure is also high, so that the control device 100 maintains the flow path switching unit 74 with the destination of the refrigerant as the suction port G1 and does not switch the flow path.

As described above, when the pressure difference between the pipe 82 and the pipe 94 is small, the control device 100 controls the flow path switching unit 74 so as to increase the pressure difference, and the refrigerant is transferred from the intermediate pressure port G3 to the suction port G1. Switch the destination of. Therefore, since the amount of decompression in the third expansion valve 71 can be secured, the amount of temperature decrease in the third expansion valve 71 increases. Thereby, the temperature difference between the refrigerant temperature of the first passage H1 and the refrigerant temperature of the second passage H2 of the heat exchanger 30 can be secured. Therefore, the amount of heat exchanged by the heat exchanger 30 increases, and the refrigerant temperature T2 can be lowered.

It is preferable to switch the flow path while the operation is stopped as shown in the flowchart of FIG. 2 because the behavior is stable, but during the operation without performing the processes of steps S4 and S7 among the processes of steps S4 to S7. The flowchart may be modified to switch the flow path. Similarly, the flowchart may be modified so that the flow path is switched during operation without performing the processes of steps S10 and S13 among the processes of steps S10 to S13.

FIG. 3 is a flowchart for explaining the control of the third expansion valve 71. With reference to FIGS. 1 and 3, the third expansion valve 71 is feedback-controlled so that the discharge temperature TH of the compressor 10 matches the target temperature. Specifically, in step S21, when the discharge temperature TH of the compressor 10 is higher than the target temperature (YES in S21), the control device 100 increases the opening degree of the third expansion valve 71 in step S22. As a result, the amount of refrigerant flowing into the intermediate pressure port G3 or the suction port G1 via the liquid receiver 73 increases, so that the discharge temperature TH decreases.

On the other hand, when the discharge temperature TH of the compressor 10 is lower than the target temperature (NO in S21 and YES in S23), the control device 100 reduces the opening degree of the third expansion valve 71 in step S24. As a result, the amount of refrigerant flowing into the intermediate pressure port G3 or the suction port G1 via the liquid receiver 73 is reduced, so that the discharge temperature TH rises.

If the discharge temperature TH = target temperature (NO in S21 and NO in S23), the opening degree of the third expansion valve 71 maintains the current state.

In this way, the control device 100 controls the opening degree of the third expansion valve 71 so that the discharge temperature TH of the compressor 10 approaches the target temperature.

Note that the frequency of changing the opening degree of the third expansion valve 71 may be reduced by setting the target temperature in step S21> the target temperature in step S23.

FIG. 4 is a flowchart for explaining the control of the fourth expansion valve 72. With reference to FIGS. 1 and 4, in the fourth expansion valve 72, in order to ensure the degree of supercooling of the refrigerant at the outlet of the condenser 20, the refrigerant temperature T1 at the outlet of the condenser 20 matches the target temperature. Feedback is controlled. Specifically, in step S31, when the supercooling degree SC determined by the refrigerant temperature T1 at the outlet of the condenser 20 and the pressure of the condenser 20 (approximate by PH) is larger than the target value (YES in S31), control is performed. The device 100 increases the opening degree of the fourth expansion valve 72 in step S32. As a result, the gas refrigerant is discharged from the receiver 73 and the amount of liquid refrigerant increases, so that the amount of refrigerant circulating in the main circuit decreases, so that the refrigerant temperature rises as a whole and the refrigerant temperature T1 rises. Cooling degree SC decreases.

On the other hand, when the supercooling degree SC determined by the refrigerant temperature T1 at the outlet of the condenser 20 and the pressure of the condenser 20 (approximate by PH) is smaller than the target value (YES in S33), the control device 100 is set in step S34. The opening degree of the fourth expansion valve 72 is reduced. As a result, the amount of gas refrigerant in the receiver 73 increases and the amount of liquid refrigerant decreases, so that the amount of refrigerant circulating in the main circuit increases, so that the refrigerant temperature as a whole decreases and the refrigerant temperature T1 decreases. Cooling degree SC increases.

If the degree of supercooling SC = target value (NO in S31 and NO in S33), the opening degree of the fourth expansion valve 72 maintains the current state.

In this way, the control device 100 controls the opening degree of the fourth expansion valve 72 so that the refrigerant temperature T1 at the outlet of the condenser 20 approaches the target temperature.

Note that the frequency of changing the opening degree of the fourth expansion valve 72 may be reduced by setting the target value in step S31> the target value in step S33.

The control device 100 controls the compressor 10 and the second expansion valve 40 so as to use the supercritical region of the refrigerant. For example, when the outside air temperature is higher than the supercritical temperature of the refrigerant, such as in summer, the control device 100 increases the rotation speed of the compressor 10 to be higher than in spring or autumn to increase the pressure in the high pressure portion. In this case, the pressure in the high voltage portion of the main circuit becomes high. Depressurization is performed by the second expansion valve 40 so that the load device 3 can be shared with a device normally used as a refrigerant. At this time, the second expansion valve 40 is controlled as follows.

FIG. 5 is a flowchart for explaining the control of the second expansion valve 40. With reference to FIGS. 1 and 5, the second expansion valve 40 is feedback-controlled so that the pressure P1 matches the target pressure. Specifically, in step S41, when the pressure P1 is higher than the target pressure (YES in S41), the control device 100 reduces the opening degree of the second expansion valve 40 in step S42. As a result, the amount of decompression by the second expansion valve 40 increases, so that the pressure P1 decreases.

On the other hand, when the pressure P1 is lower than the target pressure (NO in S41 and YES in S43), the control device 100 increases the opening degree of the second expansion valve 40 in step S44. As a result, the amount of decompression by the second expansion valve 40 is reduced, so that the pressure P1 rises.

If the pressure P1 = the target pressure (NO in S41 and NO in S43), the opening degree of the second expansion valve 40 maintains the current state.

Since the pressure P1 is controlled in this way, the pressure in the load device 3 can be set to be equal to or lower than the design pressure of the device normally used as a refrigerant, and the load device of the conventional machine using a refrigerant such as R410A can be shared. Is possible.

Although the present embodiment has been described above by exemplifying a refrigerator provided with the refrigeration cycle device 1, the refrigeration cycle device 1 may be used as an air conditioner or the like.

The embodiments disclosed this time should be considered to be exemplary in all respects and not restrictive. The scope of the present invention is shown by the claims rather than the description of the embodiments described above, and is intended to include all modifications within the meaning and scope equivalent to the claims.

1 Refrigeration cycle device, 2 Outdoor unit, 3 Load device, 10 Compressor, 20 Condenser, 22 Fan, 30 Heat exchanger, 40 2nd expansion valve, 50 1st expansion valve, 60 Evaporator, 71 3rd expansion valve , 72 4th expansion valve, 73 receiver, 74 flow path switching part, 75,76 on-off valve, 80,81,82,83,85,89,91,94,96,97,98 piping, 84,88 Extension piping, 93 degassing passage, 100 control device, 102 CPU, 104 memory, 110, 111, 112 pressure sensor, 120, 121, 122 temperature sensor, G1 suction port, G2 discharge port, G3 intermediate pressure port, H1 first Passage, H2 2nd passage.

Claims

An outdoor unit of a refrigeration cycle device configured to be connected to a load device including a first expansion valve and an evaporator.
A compressor with a suction port, a discharge port, and an intermediate pressure port,
Condenser and
A heat exchanger having a first passage and a second passage and configured to exchange heat between the refrigerant flowing through the first passage and the refrigerant flowing through the second passage.
Equipped with a second expansion valve
The flow path from the compressor to the condenser, the first passage of the heat exchanger, and the second expansion valve forms a circulation flow path through which the refrigerant circulates together with the load device.
A first refrigerant flow path for flowing a refrigerant from a portion of the circulation flow path between the outlet of the first passage and the second expansion valve to the inlet of the second passage.
A third expansion valve arranged in the first refrigerant flow path and
A second refrigerant flow path for flowing a refrigerant from the outlet of the second passage to the suction port or the intermediate pressure port of the compressor.
An outdoor unit further provided with a flow path switching unit arranged in the second refrigerant flow path and switching the destination of the refrigerant flowing out from the outlet of the second passage to either the suction port or the intermediate pressure port.
A receiver arranged in the first refrigerant flow path and storing the refrigerant, and
A gas vent passage provided between the outlet of the receiver and the receiver to discharge the refrigerant gas in the receiver,
Further provided with a fourth expansion valve arranged in the degassing passage,
The third expansion valve according to claim 1, wherein the third expansion valve is arranged between a portion of the circulation flow path between the outlet of the first passage and the second expansion valve and the inlet of the receiver. Outdoor unit.
A control device for controlling the flow path switching unit is further provided.
The control device controls the flow path switching unit so that the destination of the refrigerant is the suction port when the temperature at the outlet of the first passage of the heat exchanger is higher than the first temperature. The outdoor unit according to 2.
The control device controls the flow path switching unit so that the destination of the refrigerant is the intermediate pressure port when the temperature at the outlet of the first passage of the heat exchanger is lower than the second temperature. Item 3. The outdoor unit according to item 3.
The outdoor unit according to claim 3, wherein the control device controls the opening degree of the third expansion valve so that the refrigerant temperature of the discharge port of the compressor approaches the target temperature.
The outdoor unit according to claim 3, wherein the control device controls the opening degree of the fourth expansion valve so that the refrigerant temperature at the outlet of the condenser approaches the target temperature.
The outdoor unit according to any one of claims 3 to 6, wherein the control device controls the compressor and the second expansion valve so as to use the supercritical region of the refrigerant.
A refrigeration cycle device including the outdoor unit according to any one of claims 1 to 7 and the load device.
A refrigerator equipped with the refrigeration cycle device according to claim 8.