EP4286774A1

EP4286774A1 - Refrigeration cycle device

Info

Publication number: EP4286774A1
Application number: EP21922799.8A
Authority: EP
Inventors: Tomotaka Ishikawa; So Nomoto; Kosuke Tanaka
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2021-01-27
Filing date: 2021-01-27
Publication date: 2023-12-06
Also published as: EP4286774A4; JP7450772B2; CN116685814A; JPWO2022162775A1; WO2022162775A1

Abstract

A refrigeration cycle apparatus (100) includes a refrigerant circuit (101) and a gas-liquid separation circuit (102). The gas-liquid separation circuit (102) includes an internal heat exchanger (5), a receiver (6), a first valve (7), and a second valve (8). The internal heat exchanger (5) includes a first path (51) and a second path (52). The gas-liquid separation circuit (102) includes a first flow path (P1) and a second flow path (P2). The second flow path (P2) is configured to branch from the first flow path (P1) between the internal heat exchanger (5) and the receiver (6), and merge into the first flow path (P1) between the first valve (7) and the refrigerant circuit (101).

Description

TECHNICAL FIELD

The present disclosure relates to a refrigeration cycle apparatus.

BACKGROUND ART

In a refrigeration cycle apparatus, excess refrigerant occurs due to the operating state, the outdoor air temperature, and the like. For example, International Publication No. 2020/208752 (PTL 1) discloses a refrigeration cycle apparatus in which gas-liquid two-phase refrigerant is separated into gas refrigerant and liquid refrigerant, and excess refrigerant is stored as liquid refrigerant in a receiver. The receiver has an upper end provided with a refrigerant inlet and a gas outlet. The receiver also has a lower end provided with a refrigerant outlet.

CITATION LIST

PATENT LITERATURE

PTL 1: International Publication No. 2020/208752

SUMMARY OF INVENTION

TECHNICAL PROBLEM

In the refrigeration cycle apparatus, when the liquid refrigerant stored in the receiver increases, the liquid level of the liquid refrigerant rises and the liquid refrigerant flows out through the gas outlet provided at the upper end of the receiver. Thus, the gas-liquid separation efficiency decreases. In order not to decrease the gas-liquid separation efficiency, the receiver needs to be increased in size such that the liquid refrigerant does not flow out through the gas outlet even when the liquid refrigerant stored in the receiver increases.
The present disclosure has been made in view of the above-described problems, and an object of the present disclosure is to provide a refrigeration cycle apparatus in which a receiver can be reduced in size while allowing reliable gas-liquid separation of refrigerant.

SOLUTION TO PROBLEM

A refrigeration cycle apparatus of the present disclosure includes a refrigerant circuit and a gas-liquid separation circuit. The refrigerant circuit includes: a compressor configured to compress refrigerant; a condenser configured to condense the refrigerant discharged from the compressor; a decompression device configured to decompress the refrigerant flowing out of the condenser; and an evaporator configured to evaporate the refrigerant flowing out of the decompression device. The gas-liquid separation circuit is connected to the refrigerant circuit between the condenser and the decompression device, and to the compressor, or the refrigerant circuit between the compressor and the evaporator. The gas-liquid separation circuit includes: an internal heat exchanger; a receiver configured to store the refrigerant flowing out of the internal heat exchanger; a first valve configured to adjust a flow rate of the refrigerant flowing out of the receiver; and a second valve connected to the internal heat exchanger and the receiver. The internal heat exchanger has: a first path through which the refrigerant flowing out of the condenser flows; and a second path through which the refrigerant flowing out of the first path flows. The internal heat exchanger is configured to exchange heat between the refrigerant flowing through the first path and the refrigerant flowing through the second path. The gas-liquid separation circuit has: a first flow path having the first path of the internal heat exchanger, the receiver, and the first valve; and a second flow path having the second path of the internal heat exchanger and the second valve. The second flow path is configured to branch from the first flow path between the internal heat exchanger and the receiver, and merge into the first flow path between the first valve and the refrigerant circuit.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the refrigeration cycle apparatus of the present disclosure, the receiver can be reduced in size while allowing reliable gas-liquid separation of the refrigerant by the gas-liquid separation circuit.

BRIEF DESCRIPTION OF DRAWINGS

Fig. 1 is a refrigerant circuit diagram of a refrigeration cycle apparatus according to an embodiment.
Fig. 2 is a refrigerant circuit diagram showing an operation of the refrigeration cycle apparatus according to the embodiment.
Fig. 3 is a refrigerant circuit diagram of a first modification of the refrigeration cycle apparatus according to the embodiment.
Fig. 4 is a refrigerant circuit diagram of a second modification of the refrigeration cycle apparatus according to the embodiment.
Fig. 5 is a refrigerant circuit diagram of a refrigeration cycle apparatus of a comparative example.

DESCRIPTION OF EMBODIMENTS

The following describes embodiments with reference to the accompanying drawings. In the following description, the same or corresponding portions are denoted by the same reference characters, and redundant description will not be repeated.
Referring to Fig. 1, a configuration of a refrigeration cycle apparatus 100 according to the first embodiment will be hereinafter described. Fig. 1 is a refrigerant circuit diagram of refrigeration cycle apparatus 100 according to an embodiment. Refrigeration cycle apparatus 100 according to the embodiment is a refrigerator, for example.
As shown in Fig. 1, refrigeration cycle apparatus 100 according to the embodiment includes a refrigerant circuit 101, a gas-liquid separation circuit 102, and a controller 103. The refrigerant circulating through refrigeration cycle apparatus 100 is carbon dioxide (CO₂), for example.
Refrigerant circuit 101 includes a compressor 1, a condenser 2, a decompression device 3, and an evaporator 4. Compressor 1, condenser 2, decompression device 3, and evaporator 4 are connected through pipes to constitute refrigerant circuit 101. Refrigerant circuit 101 is configured such that refrigerant flows through compressor 1, condenser 2, decompression device 3, and evaporator 4 in this order.
Compressor 1 is configured to compress refrigerant. Compressor 1 is configured to suction refrigerant, compress the suctioned refrigerant, and discharge the compressed refrigerant. Compressor 1 is configured to compress the refrigerant to be brought into a high-temperature and high-pressure state. In the present embodiment, compressor 1 includes an injection port provided in an intermediate pressure portion.
Compressor 1 may be configured such that its displacement is variable. Compressor 1 may be configured such that its displacement is varied in accordance with the rotation speed adjusted by changing the frequency based on an instruction from controller 103.
Condenser 2 is configured to condense the refrigerant discharged from compressor 1. Condenser 2 is configured to cool the refrigerant discharged from compressor 1 so as to condense the refrigerant. Condenser 2 is, for example, a fin-and-tube type heat exchanger including a plurality of fins and a heat transfer tube penetrating the plurality of fins.
Decompression device 3 is configured to decompress the refrigerant having flowed out of condenser 2. Decompression device 3 is an expansion valve. Decompression device 3 is an electromagnetic valve, for example. Decompression device 3 is configured to adjust the flow rate of the refrigerant based on an instruction from controller 103.
Evaporator 4 is configured to evaporate the refrigerant having flowed out of decompression device 3. Evaporator 4 is configured to heat and evaporate the refrigerant having flowed out of decompression device 3. Evaporator 4 is, for example, a fin-and-tube type heat exchanger including a plurality of fins and a heat transfer tube penetrating the plurality of fins.
Gas-liquid separation circuit 102 is connected to refrigerant circuit 101 between condenser 2 and decompression device 3, and to compressor 1 or refrigerant circuit 101 between compressor 1 and evaporator 4. In the present embodiment, gas-liquid separation circuit 102 is connected to refrigerant circuit 101 between condenser 2 and decompression device 3, and to compressor 1. Specifically, gas-liquid separation circuit 102 is connected to a pipe of refrigerant circuit 101 between condenser 2 and decompression device 3, and to the intermediate pressure side of compressor 1.
Gas-liquid separation circuit 102 includes an internal heat exchanger 5, a receiver 6, a first valve 7, and a second valve 8. Internal heat exchanger 5, receiver 6, first valve 7, second valve 8, and the pipes constitute a gas-liquid separation mechanism 10. Gas-liquid separation mechanism 10 has an inlet 11 connected to refrigerant circuit 101 between condenser 2 and decompression device 3. Gas-liquid separation mechanism 10 has a branch portion 12 disposed among internal heat exchanger 5, receiver 6, and second valve 8. Gas-liquid separation mechanism 10 has a merging portion 13 disposed among internal heat exchanger 5, first valve 7, and an outlet 14 of gas-liquid separation mechanism 10. Outlet 14 of gas-liquid separation mechanism 10 is connected to compressor 1 or to refrigerant circuit 101 between compressor 1 and evaporator 4.
Internal heat exchanger 5 is connected through a pipe to refrigerant circuit 101 between condenser 2 and decompression device 3. Internal heat exchanger 5 includes a first path 51 and a second path 52. First path 51 is configured such that the refrigerant having flowed out of condenser 2 flows therethrough. Second path 52 is configured such that the refrigerant having flowed out of first path 51 flows therethrough. Internal heat exchanger 5 is configured to exchange heat between the refrigerant flowing through first path 51 and the refrigerant flowing through second path 52. In the present embodiment, internal heat exchanger 5 is configured such that the flow of the refrigerant flowing through first path 51 is counter to the flow of the refrigerant flowing through second path 52. In other words, internal heat exchanger 5 is configured such that the refrigerant flowing through first path 51 and the refrigerant flowing through second path 52 flow as counterflows to each other. Internal heat exchanger 5 is disposed upstream of receiver 6 in the flow of refrigerant.
Receiver 6 is connected to internal heat exchanger 5, first valve 7, and second valve 8 through pipes. Receiver 6 has an upper end provided with a refrigerant inlet 6a. Receiver 6 has a lower end provided with a refrigerant outlet 6b. Receiver 6 is configured to store the refrigerant having flowed out of internal heat exchanger 5. Receiver 6 is configured to store liquefied liquid refrigerant. Receiver 6 is configured to store excess refrigerant.
First valve 7 is connected to refrigerant outlet 6b of receiver 6 through a pipe. First valve 7 is configured to adjust the flow rate of the refrigerant having flowed out of receiver 6. First valve 7 is a flow control valve, for example. First valve 7 is an electromagnetic valve, for example.
Second valve 8 is connected to internal heat exchanger 5 and receiver 6. Second valve 8 is connected through pipes to first path 51 of internal heat exchanger 5, refrigerant inlet 6a of receiver 6, and second path 52 of internal heat exchanger 5. Second valve 8 is an on-off valve, for example. Second valve 8 may be a flow control valve, for example. Second valve 8 is an electromagnetic valve, for example.
Gas-liquid separation circuit 102 includes a first flow path P1 and a second flow path P2. First flow path P1 includes first path 51 of internal heat exchanger 5, receiver 6, and first valve 7. First flow path P1 is configured such that the refrigerant flows through first path 51 of internal heat exchanger 5, receiver 6, and first valve 7 in this order. Second flow path P2 includes second path 52 of internal heat exchanger 5 and second valve 8. Second flow path P2 is configured such that the refrigerant flows through second valve 8 and second path 52 of internal heat exchanger 5 in this order.
First flow path P1 is connected to refrigerant circuit 101 between condenser 2 and decompression device 3, and to compressor 1 or refrigerant circuit 101 between compressor 1 and evaporator 4. Second flow path P2 is configured to branch from first flow path P1 between internal heat exchanger 5 and receiver 6 and then merge into first flow path P1 between first valve 7 and refrigerant circuit 101. Second flow path P2 is configured to branch from first flow path P1 at branch portion 12 and then merge into first flow path P1 at merging portion 13.
Controller 103 is configured to control the entire refrigeration cycle apparatus 100. Controller 103 is configured to control refrigerant circuit 101 and gas-liquid separation circuit 102. Controller 103 is configured to control compressor 1 and decompression device 3 in refrigerant circuit 101. Controller 103 is configured to control the opening degrees of first valve 7 and second valve 8 in gas-liquid separation circuit 102. Controller 103 is constituted of a microcomputer, for example. Controller 103 includes a central processing unit (CPU), a random access memory (RAM), a read only memory (ROM), and the like. The ROM stores a control program.
The following describes the operation of refrigeration cycle apparatus 100 according to the embodiment.
Referring to Fig. 2, the following describes the operation of refrigeration cycle apparatus 100 according to the embodiment while it operates. Fig. 2 is a refrigerant circuit diagram showing the operation of refrigeration cycle apparatus 100 according to the embodiment while it operates. In Fig. 2, each of arrows indicated in refrigerant circuit 101 and gas-liquid separation circuit 102 shows the flow of refrigerant.
The following first describes the flow of the refrigerant flowing through refrigerant circuit 101. The refrigerant having flowed into compressor 1 is compressed by compressor 1 to become high-temperature and high-pressure gas refrigerant, which is then discharged from compressor 1. The high-temperature and high-pressure gas refrigerant flows into condenser 2 and is condensed by condenser 2 to becomes liquid refrigerant, which then flows out of condenser 2. Part of the liquid refrigerant flows into decompression device 3 and is decompressed by decompression device 3 to become low-pressure gas-liquid two-phase refrigerant, which then flows out of decompression device 3. The low-pressure gas-liquid two-phase refrigerant flows into evaporator 4 and is evaporated by evaporator 4 to become gas refrigerant. The gas refrigerant flows into compressor 1. In this way, the refrigerant circulates through refrigerant circuit 101.
The following describes the flow of the refrigerant flowing through gas-liquid separation circuit 102. Part of the refrigerant having flowed out of condenser 2 flows from refrigerant circuit 101 into gas-liquid separation circuit 102. The refrigerant having flowed into gas-liquid separation circuit 102 flows into first path 51 of internal heat exchanger 5, exchanges heat with the refrigerant flowing through second path 52, and then flows out of internal heat exchanger 5. Part of the refrigerant having flowed out of first path 51 of internal heat exchanger 5 flows into receiver 6 through first path P1. In refrigerant circuit 101, excess refrigerant occurs due to the operating state of refrigeration cycle apparatus 100, the outdoor air temperature, and the like. This excess refrigerant that is liquid refrigerant is stored in receiver 6. When the liquid refrigerant stored in receiver 6 due to the operating state of refrigeration cycle apparatus 100, the outdoor air temperature and the like is required, the liquid refrigerant flows out of receiver 6 and then flows through first valve 7 into the intermediate pressure side of compressor 1.
Part of the refrigerant having flowed out of first path 51 of internal heat exchanger 5 flows out from branch portion 12 of gas-liquid separation mechanism 10 through second valve 8 into second path 52 of internal heat exchanger 5, exchanges heat with the refrigerant flowing through first path 51, and then flows out of internal heat exchanger 5. The refrigerant having flowed through second path 52 of internal heat exchanger 5 is decompressed to become superheated gas refrigerant. The superheated gas refrigerant having flowed out of second path 52 of internal heat exchanger 5 merges into the liquid refrigerant having flowed out of receiver 6 at merging portion 13 of gas-liquid separation mechanism 10, and then flows into the intermediate pressure side of compressor 1. In this way, the refrigerant flows through gas-liquid separation circuit 102.
When the opening degree of first valve 7 increases, the liquid refrigerant flows out of receiver 6, and thereby, the amount of the liquid refrigerant stored in receiver 6 decreases. When the opening degree of second valve 8 increases, the gas refrigerant leaks from receiver 6, and thereby, the amount of the liquid refrigerant stored in receiver 6 increases. In this way, the opening degrees of first valve 7 and second valve 8 are controlled to thereby control the amount of liquid refrigerant stored in receiver 6.
The following describes a modification of refrigeration cycle apparatus 100 according to the embodiment. The modification of refrigeration cycle apparatus 100 according to the embodiment has the same configuration and the same operation as those of refrigeration cycle apparatus 100 according to the embodiment unless otherwise specified.
Referring to Fig. 3, the first modification of refrigeration cycle apparatus 100 according to the embodiment will be hereinafter described. Fig. 3 is a refrigerant circuit diagram of the first modification of refrigeration cycle apparatus 100 according to the embodiment. In the first modification of refrigeration cycle apparatus 100 according to the embodiment, gas-liquid separation circuit 102 further includes a third valve 9. Third valve 9 is a flow control valve, for example. Third valve 9 is an electromagnetic valve, for example. Third valve 9 is disposed between refrigerant circuit 101 and internal heat exchanger 5.
In the first modification of refrigeration cycle apparatus 100 according to the embodiment, part of the refrigerant having flowed out of condenser 2 flows into first path 51 of internal heat exchanger 5 through third valve 9.
Referring to Fig. 4, the second modification of refrigeration cycle apparatus 100 according to the embodiment will be hereinafter described. Fig. 4 is a refrigerant circuit diagram of the second modification of refrigeration cycle apparatus 100 according to the embodiment. In the second modification of refrigeration cycle apparatus 100 according to the embodiment, gas-liquid separation circuit 102 is connected to refrigerant circuit 101 between condenser 2 and decompression device 3, and to refrigerant circuit 101 between compressor 1 and evaporator 4.
In the second modification of refrigeration cycle apparatus 100 according to the embodiment, refrigerant circuit 101 further includes an accumulator 20.
Accumulator 20 is disposed between compressor 1 and evaporator 4 in refrigerant circuit 101. Gas-liquid separation circuit 102 is connected to refrigerant circuit 101 between evaporator 4 and accumulator 20.
Accumulator 20 is configured to receive the refrigerant having flowed out of evaporator 4 and gas-liquid separation circuit 102. Accumulator 20 is configured to store the refrigerant having flowed out of evaporator 4 and gas-liquid separation circuit 102.
In the second modification of refrigeration cycle apparatus 100 according to the embodiment, the refrigerant having flowed out of evaporator 4 and gas-liquid separation circuit 102 flows into compressor 1 through accumulator 20.
The following describes functions and effects of the embodiment in comparison with a comparative example.
Referring to Fig. 5, a refrigeration cycle apparatus 100 of the comparative example will be hereinafter described. Fig. 5 is a refrigerant circuit diagram of refrigeration cycle apparatus 100 of the comparative example. In refrigeration cycle apparatus 100 of the comparative example, gas-liquid separation circuit 102 does not include internal heat exchanger 5. Receiver 6 has an upper end provided with a refrigerant inlet 6a and a gas outlet 6c. Receiver 6 has a lower end provided with a refrigerant outlet 6b. In refrigeration cycle apparatus 100 of the comparative example, when the liquid refrigerant stored in receiver 6 increases, the liquid level of the liquid refrigerant rises, and then, the liquid refrigerant flows out through gas outlet 6c provided at the upper end of receiver 6. Thus, the gas-liquid separation efficiency decreases. In order not to decrease the gas-liquid separation efficiency, receiver 6 needs to be increased in size such that the liquid refrigerant does not flow out through the gas outlet even when the liquid refrigerant stored in receiver 6 increases.
On the other hand, according to refrigeration cycle apparatus 100 of the embodiment, receiver 6 not having gas outlet 6c can prevent the liquid refrigerant from flowing out through gas outlet 6c of receiver 6 even when the liquid refrigerant stored in receiver 6 increases to thereby raise the liquid level of the liquid refrigerant. Further, internal heat exchanger 5 decompresses the refrigerant, and thereby, gas refrigerant can be separated. Therefore, gas-liquid separation of the refrigerant can be reliably done. Further, even when the liquid refrigerant stored in receiver 6 increases and the liquid level of the liquid refrigerant rises, the liquid refrigerant can be prevented from flowing out through gas outlet 6c of receiver 6, so that the liquid refrigerant can be stored up to the upper end of receiver 6. Thus, receiver 6 can be reduced in size while being capable of storing the same amount of liquid refrigerant. Accordingly, receiver 6 can be reduced in size. Therefore, according to refrigeration cycle apparatus 100 of the embodiment, receiver 6 can be reduced in size while allowing reliable gas-liquid separation of the refrigerant by gas-liquid separation circuit 102.
In refrigeration cycle apparatus 100 according to the embodiment, since the amount of refrigerant in receiver 6 can be controlled, the performance can be improved. Further, since the amount of refrigerant in receiver 6 can be controlled, the operating range of refrigeration cycle apparatus 100 can be enlarged.
According to refrigeration cycle apparatus 100 of the embodiment, second valve 8 is a flow control valve. Thus, by controlling the opening degree of this flow control valve, the refrigerant in internal heat exchanger 5 can be reliably gasified. Further, by controlling the opening degree of the flow control valve, the accuracy in controlling the amount of liquid refrigerant stored in receiver 6 can be improved.
According to refrigeration cycle apparatus 100 of the embodiment, internal heat exchanger 5 is configured such that the flow of the refrigerant flowing through first path 51 is counter to the flow of the refrigerant flowing through second path 52. This can facilitate superheated gasification of the refrigerant in internal heat exchanger 5.
According to refrigeration cycle apparatus 100 of the embodiment, the refrigerant is carbon dioxide. Since carbon dioxide is high-pressure refrigerant used in a supercritical pressure condition, such carbon dioxide is higher in pressure than the refrigerant other than high-pressure refrigerant such as R32. In refrigeration cycle apparatus 100 according to the embodiment, since receiver 6 can be reduced in size, a container can be relatively increased in thickness. Thereby, the resistance to pressure in receiver 6 can be enhanced, and thus, carbon dioxide can be suitably used as refrigerant.
According to refrigeration cycle apparatus 100 of the embodiment, gas-liquid separation circuit 102 is connected to refrigerant circuit 101 between condenser 2 and decompression device 3, and to compressor 1. This eliminates the need to install accumulator 20 in refrigerant circuit 101 for suppressing the liquid refrigerant from flowing into compressor 1. Therefore, refrigeration cycle apparatus 100 can be simplified in structure.
According to the first modification of refrigeration cycle apparatus 100 of the embodiment, the flow ratio of the refrigerant flowing through internal heat exchanger 5 and receiver 6 can be adjusted by adjusting the opening degrees of first valve 7 and third valve 9.
According to the second modification of refrigeration cycle apparatus 100 of the embodiment, gas-liquid separation circuit 102 is connected to refrigerant circuit 101 between condenser 2 and decompression device 3, and to refrigerant circuit 101 between compressor 1 and evaporator 4. Thus, since gas-liquid separation circuit 102 is not connected to the intermediate pressure side of compressor 1, the degree of freedom in designing of compressor 1 can be improved. Therefore, the degree of freedom in designing of refrigeration cycle apparatus 100 can be improved.
According to the second modification of refrigeration cycle apparatus 100 of the embodiment, since the refrigerant having flowed out of gas-liquid separation circuit 102 flows into compressor 1 through accumulator 20, the liquid refrigerant having flowed out of gas-liquid separation circuit 102 can be suppressed from flowing into the inlet of compressor 1.
It should be understood that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present disclosure is defined by the scope of the claims, rather than the description above, and is intended to include any modifications within the meaning and scope equivalent to the claims.

REFERENCE SIGNS LIST

1 compressor, 2 condenser, 3 decompression device, 4 evaporator, 5 internal heat exchanger, 6 receiver, 7 first valve, 8 second valve, 9 third valve, 10 gas-liquid separation mechanism, 11 inlet, 12 branch portion, 13 merging portion, 14 outlet, 20 accumulator, 51 first path, 52 second path, 100 refrigeration cycle apparatus, 101 refrigerant circuit, 102 gas-liquid separation circuit, 103 controller.

Claims

A refrigeration cycle apparatus comprising:
a refrigerant circuit comprising
a compressor configured to compress refrigerant,

a condenser configured to condense the refrigerant discharged from the compressor,

a decompression device configured to decompress the refrigerant flowing out of the condenser, and

an evaporator configured to evaporate the refrigerant flowing out of the decompression device; and

a gas-liquid separation circuit connected to
the refrigerant circuit between the condenser and the decompression device, and

the compressor, or the refrigerant circuit between the compressor and the evaporator, wherein

the gas-liquid separation circuit comprises
an internal heat exchanger,

a receiver configured to store the refrigerant flowing out of the internal heat exchanger,

a first valve configured to adjust a flow rate of the refrigerant flowing out of the receiver, and

a second valve connected to the internal heat exchanger and the receiver, the internal heat exchanger has

a first path through which the refrigerant flowing out of the condenser flows, and

a second path through which the refrigerant flowing out of the first path flows,

the internal heat exchanger is configured to exchange heat between the refrigerant flowing through the first path and the refrigerant flowing through the second path,

the gas-liquid separation circuit has
a first flow path having the first path of the internal heat exchanger, the receiver, and the first valve, and

a second flow path having the second path of the internal heat exchanger and the second valve, and

the second flow path is configured to
branch from the first flow path between the internal heat exchanger and the receiver, and

merge into the first flow path between the first valve and the refrigerant circuit.
The refrigeration cycle apparatus according to claim 1, wherein the second valve is a flow control valve.
The refrigeration cycle apparatus according to claim 1 or 2, wherein the internal heat exchanger is configured such that a flow of the refrigerant flowing through the first path is counter to a flow of the refrigerant flowing through the second path.
The refrigeration cycle apparatus according to any one of claims 1 to 3, wherein the refrigerant is carbon dioxide.