EP2667120A1

EP2667120A1 - Refrigeration cycle apparatus

Info

Publication number: EP2667120A1
Application number: EP11855961.6A
Authority: EP
Inventors: Daisuke Shimamoto; Osamu Morimoto
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2011-01-20
Filing date: 2011-01-20
Publication date: 2013-11-27
Anticipated expiration: 2031-01-20
Also published as: EP2667120A4; EP2905562B1; EP2667120B1; JP5762441B2; EP2905562A1; WO2012098582A1; JPWO2012098582A1

Abstract

A refrigeration cycle apparatus including a main refrigerant circuit, through which a refrigerant circulates through a compressor 1, a heat-source-side heat exchanger 3, a first flow rate control device 4, and a use-side heat exchanger 5, includes a first gas-liquid separator 20; and a foreign-substance recovery container 8 that recovers a foreign substance contained in the refrigerant. A foreign-substance recovery refrigerant circuit that connects the first gas-liquid separator 20 with the foreign-substance recovery container 8 through a first passage opening and closing device 10 is arranged between a suction side of the compressor 1 and the use-side heat exchanger 5, in parallel with the main refrigerant circuit.

Description

Technical Field

This invention relates to a refrigeration cycle apparatus including means for physically cleaning a foreign substance with a refrigerant, when an extension pipe part of a refrigeration cycle apparatus that used mineral oil, such as mineral oil used for a CFC refrigerant or an HCFC refrigerant, as refrigerating machine oil, is reused in a refrigeration cycle apparatus that uses another refrigerant for an HFC refrigerant system or the like, the foreign substance being mainly mineral oil and a deteriorated substance of the mineral oil remaining in the extension pipe part.

Background Art

A known conventional cleaning technique for an extension pipe is as follows. An air-conditioning device and a use-side heat exchanger, which are connected with an existing pipe and required to be replaced, are removed, and a cleaning device and a bypass pipe are connected with the existing pipe. After the connection, a vacuum is created in the entire refrigeration cycle, and R407C is appropriately filled. Then, a compressor is operated. A high-temperature high-pressure gas refrigerant discharged from the compressor first passes through an oil separator. In this phase, refrigerating machine oil discharged from the compressor together with the gas refrigerant is separated by the oil separator, and is returned to a suction side of the compressor. The high-temperature high-pressure gas refrigerant then passes through a four-way valve, the gas is partly cooled by a high-low pressure heat exchanger and becomes liquid, and the refrigerant becomes a high-pressure two-phase gas-liquid refrigerant. The high-pressure two-phase gas-liquid refrigerant passes through the existing pipe, the bypass pipe, and the existing pipe, then the pressure of the refrigerant is reduced by a pressure reducing device, and the refrigerant becomes a low-pressure two-phase gas-liquid refrigerant. Then, the refrigerant is heated by the high-low pressure heat exchanger and becomes low-pressure gas. Then, the gas passes through a separating device, at this time, the mineral oil cleaned in the existing pipe is separated, and the mineral oil is held in the separating device. The temperature of the low-pressure refrigerant gas is decreased by a heat-source-side heat exchanger to prevent a discharge temperature of the compressor from becoming too high, and the gas is sucked by the compressor through the four-way valve and an accumulator (Patent Literature 1).

Citation List

Patent Literature

Patent Literature 1: Japanese Patent No. 3521820

Summary of Invention

Technical Problem

With the conventional technique like Patent Literature 1, foreign-substance capturing means that contributes to cleaning for a foreign substance such as mineral oil is arranged at a low-pressure side of a cooling operation. Hence, performance has been likely degraded due to a pressure loss. Also, a structure is markedly different from that of an air-conditioning apparatus including a normal refrigeration cycle. Hence, standardization and optional provision of the foreign-substance capturing means have been difficult. Also, heat exchange is performed between main pipes. Hence, a heat exchanger at this portion has been increased in size and cost. An object of the invention is to address at least one of these problems. Solution to Problem
A refrigeration cycle apparatus according to a first invention of this invention is a refrigeration cycle apparatus including a main refrigerant circuit, through which a refrigerant circulates through a compressor, a heat-source-side heat exchanger, a first flow rate control device, and a use-side heat exchanger. The refrigeration cycle apparatus includes a first gas-liquid separator; and a foreign-substance recovery container that recovers a foreign substance contained in the refrigerant. A foreign-substance recovery refrigerant circuit that connects the first gas-liquid separator with the foreign-substance recovery container through a first passage opening and closing device is arranged between a suction side of the compressor and the use-side heat exchanger, in parallel with the main refrigerant circuit.
A low-pressure-side pipe of a high-low pressure heat exchanger, a second gas-liquid separator, and a second passage opening and closing device are preferably connected in that order between the first passage opening and closing device and the foreign-substance recovery container. In this case, a position of the first gas-liquid separator is preferably higher than a position of the second gas-liquid separator.
Also, if an accumulator is provided between the compressor and the use-side heat exchanger, an entrance of the foreign-substance recovery refrigerant circuit is preferably connected with an inlet of the accumulator, and an exit of the foreign-substance recovery refrigerant circuit is preferably connected with an outlet of the accumulator.

Advantageous Effects of Invention

With the refrigeration cycle apparatus configured as described above, a difference in refrigerant circuit configuration is small with respect to a configuration of a refrigeration cycle without the foreign-substance recovery refrigerant circuit. Accordingly, the foreign-substance recovery refrigerant circuit that can be easily added and that is low in cost can be realized.

Brief Description of Drawings

[Fig. 1] Fig. 1 is a refrigerant circuit diagram of a refrigeration cycle apparatus according to Embodiment 1 of this invention.
[Fig. 2] Fig. 2 is a flow diagram of a refrigerant in a cooling operation state according to Embodiment 1 of this invention.
[Fig. 3] Fig. 3 is a flow diagram of the refrigerant in a heating operation state according to Embodiment 1 of this invention.
[Fig. 4] Fig. 4 is a flowchart of a cleaning control method for an extension pipe according to Embodiment 1 of this invention.
[Fig. 5] Fig. 5 is a refrigerant circuit diagram of a refrigeration cycle apparatus according to Embodiment 2 of this invention.
[Fig. 6] Fig. 6 is a configuration diagram showing an example of foreign-substance capturing means according to Embodiment 1 of this invention. Description of Embodiments

Embodiment 1

Fig. 1 is a refrigerant circuit diagram of a refrigeration cycle apparatus (an air-conditioning apparatus) according to Embodiment 1 of this invention. A main refrigerant circuit of this air-conditioning apparatus includes, for example, a compressor 1; a four-way valve 2 serving as a flow switching valve; heat-source- side heat exchangers 3A and 3B; first flow rate control devices 4A, 4B, and 4C that control flow rates of a refrigerant in refrigerant circuits; use- side heat exchangers 5A, 5B, and 5C; and an accumulator 9. The accumulator 9 may be provided as required.
A series circuit of the first flow rate control device 4A and the use-side heat exchanger 5A, a series circuit of the first flow rate control device 4B and the use-side heat exchanger 5B, and a series circuit of the first flow rate control device 4C and the use-side heat exchanger 5C are respectively components of an indoor unit A, an indoor unit B, and an indoor unit C, and are connected in parallel. The number of the indoor units is not particularly limited.
Also, an oil recovery unit 23 is provided between the compressor 1 and the four-way valve 2, and a first gas-liquid separator 20 is provided between the four-way valve 2 and the accumulator 9 (if the accumulator 9 is not provided, the compressor 1).
A double-pipe heat exchanger 7 is provided between the heat-source- side heat exchangers 3A and 3B, and the first flow rate control devices 4A, 4B, and 4C. The double-pipe heat exchanger 7 includes a high-pressure-side pipe 7A and a low-pressure-side pipe 7B and serves as a high-low pressure heat exchanger. Also, a third flow rate control device 27 and a fifth opening and closing valve 28 are provided between the double-pipe heat exchanger 7 and the first flow rate control devices 4A, 4B, and 4C. The third flow rate control device 27 controls a downstream pressure during a cooling operation. Further, a sixth opening and closing valve 29 is provided between the use- side heat exchangers 5A, 5B, and 5C, and the four-way valve 2.
It is assumed that a pipe that connects the fifth opening and closing valve 28 with the first flow rate control devices 4A, 4B, and 4C is called liquid-side extension pipe (E), and a pipe that connects the sixth opening and closing valve 29 with the use- side heat exchangers 5A, 5B, and 5C is called gas-side extension pipe (F).
A refrigerant circulates in the main refrigerant circuit configured as described above, in accordance with a direction of the four-way valve 2, the direction which is switched depending on whether operation is the cooling operation or a heating operation.
In this air-conditioning apparatus, a first bypass is further provided, in which a second flow rate control device 6, the low-pressure-side pipe 7B of the double-pipe heat exchanger 7, a second gas-liquid separator 21, a second opening and closing valve 11 serving as a second passage opening and closing device, a foreign-substance recovery container 8, and a first check valve 12 are connected in series. The first bypass is divided from a pipe between the heat-source-side heat exchanger 3 and the third flow rate control device 27, and is connected with a refrigerant pipe between the compressor 1 and the accumulator 9 (if the accumulator 9 is not provided, the first gas-liquid separator 20).
Also, a pipe between the accumulator 9 and the first gas-liquid separator 20 is connected with the second gas-liquid separator 21 through a second bypass including a second check valve 26.
Further, a pipe between the second flow rate control device 6 and the low-pressure-side pipe 7B of the double-pipe heat exchanger 7 is connected with the first gas-liquid separator 20 through a third bypass including a first opening and closing valve 10 serving as a first passage opening and closing device.
The first gas-liquid separator 20, the first opening and closing valve 10, the low-pressure-side pipe 7B of the double-pipe heat exchanger 7, the second gas-liquid separator 21, the second opening and closing valve 11, and the foreign-substance recovery container 8 form a foreign-substance recovery refrigerant circuit serving as foreign-substance recovery means for recovering a foreign substance in the refrigerant.
The normal direction of the first check valve 12 is a direction toward the compressor 1, and the normal direction of the second check valve 26 is a direction toward the accumulator 9.
Also, the first gas-liquid separator 20 causes a liquid phase to flow toward the first opening and closing valve 10, and causes a gas phase to flow toward the accumulator 9.
Also, the second gas-liquid separator 21 causes a liquid phase to flow toward the second opening and closing valve 11, and causes a gas phase to flow toward the second check valve 26.
Also, first pressure detecting means 13 and second pressure detecting means 14 are respectively connected at a discharge side and a suction side of the compressor 1.
In addition, third pressure detecting means 15 is connected with middle part of a pipe that connects the third flow rate control device 27 with the fifth opening and closing valve 28.
Further, first temperature detecting means 16 is provided at the discharge side of the compressor 1, and second temperature detecting means 17 is provided at a pipe between the low-pressure-side pipe 7B of the double-pipe heat exchanger 7 and the second gas-liquid separator 21.
Third temperature detecting means 18A, 18B, and 18C are respectively connected between the first flow rate control devices 4A, 4B, and 4C, and the corresponding use- side heat exchangers 5A, 5B, and 5C.
Also, fourth temperature detecting means 19A, 19B, and 19C are respectively connected between the use- side heat exchangers 5A, 5B, and 5C, and the gas-side extension pipe (F), at the use-side heat exchanger sides.
Further, fifth temperature detecting means 22 is provided for detecting an outdoor temperature.
Elements surrounded by a broken line in Fig. 1 represent components of an outdoor unit (D).
Next, a flow of the refrigerant in the refrigerant circuit shown in Fig. 1 is described with reference to Figs. 2 and 3. As shown in Fig. 2, in a normal cooling operation, a refrigerant containing refrigerating machine oil is discharged from the compressor 1, the refrigerating machine oil is separated by the oil recovery unit 23, the refrigerant passes through the four-way valve 2, and the refrigerant exchanges heat with the air by the heat-source-side heat exchanger 3, so that the refrigerant is condensed and liquefied. Then, the refrigerant is further cooled in the high-pressure-side pipe 7A of the double-pipe heat exchanger 7, the pressure of part of the cooled refrigerant is adjusted by the third flow rate control device 27, then the refrigerant passes through the fifth opening and closing valve 28 being open, and then the refrigerant enters the first flow rate control devices 4A, 4B, and 4C of the indoor units through the liquid-side extension pipe (E). The refrigerant with the pressure reduced by the first flow rate control devices 4A, 4B, and 4C exchanges heat with the air in the use- side heat exchangers 5A, 5B, and 5C, so that the refrigerant is evaporated and gasified; the refrigerant passes through the liquid-side extension pipe (F), the sixth opening and closing valve 29 being open, the four-way valve 2, the first gas-liquid separator 20, and the accumulator 9; and the refrigerant is returned to the suction side of the compressor 1.
In contrast, part of the refrigerant after the refrigerant passes through the high-pressure-side pipe 7A of the double-pipe heat exchanger 7 is reduced in pressure by the second flow rate control device 6; the refrigerant exchanges heat in the low-pressure-side pipe 7B of the double-pipe heat exchanger with the high-pressure-side pipe 7A, so that the refrigerant is evaporated; the refrigerant passes through the second gas-liquid separator 21 and the second check valve 26; and the refrigerant flows into the pipe that connects the first gas-liquid separator 20 with the accumulator 9. In normal cooling operation, the first opening and closing valve 10 and the second opening and closing valve 11 are closed, and the refrigerant does not flow from the first gas-liquid separator 20 to the first opening and closing valve 10, or from the second gas-liquid separator 21 to the second opening and closing valve 11.
The first flow rate control devices 4A, 4B, and 4C control respective differences of detected temperature between the fourth temperature detecting devices 19A, 19B, and 19C and the third temperature detecting devices 18A, 18B, and 18C to be a constant numerical value, for example, "2." The second flow rate control device 6 adjusts a difference of detected temperature between the second temperature detecting device 17 and a saturation temperature of detected pressure of the second pressure detecting device 14 to be, for example, "5." The third flow rate control device 27 adjusts a numerical value of the third pressure detecting device 15 to be, for example, "3.0 MPa." The control value provided by the third pressure detecting device 15 is a value set to be equal to or smaller than an allowable value for a pipe.
In the heating operation, mineral-oil recovery operation is not performed, but only a normal heating operation is performed. As shown in Fig. 3, the refrigerant containing the refrigerating machine oil is discharged from the compressor 1; the refrigerating machine oil is separated by the oil recovery unit 23, the refrigerant passes through the four-way valve 2, the sixth opening and closing valve 29 being open, and the liquid-side extension pipe (F); then the refrigerant exchanges heat with the air in the use- side heat exchangers 5A, 5B, and 5C, so that the refrigerant is condensed and liquefied; and the refrigerant is reduced in pressure by the first flow rate control devices 4A, 4B, and 4C, so that the refrigerant becomes a two-phase state. The refrigerant in the two-phase state passes through the gas-side extension pipe (E), the fifth opening and closing valve 28 being open, the third flow rate control device 27 being full open, and the pipe 7A of the double-pipe heat exchanger; the refrigerant exchanges heat with the air by the heat-source-side heat exchanger 3, so that the refrigerant is evaporated and gasified; and then the refrigerant is returned to the suction side of the compressor 1 through the four-way valve 2. Since the second flow rate control device 6 is full open, the refrigerant does not flow to the pipe 7B of the double-pipe heat exchanger. Also, if the first flow rate control devices 4A, 4B, and 4C are controlled, subcooling at exit portions of the use- side heat exchangers 5A, 5B, and 5C can be controlled. The subcooling at the exit portions is indicated by values, each of which is obtained by subtracting corresponding one of detected temperatures by the second temperature detecting means 18A, 18B, and 18C from a saturation temperature of a detected pressure by the first pressure detecting means 13.
Described next is a flow of the refrigerant during a foreign-substance recovery operation for recovering a foreign substance, which mainly contains the mineral oil and the deteriorated substance of the mineral oil remaining in the gas-side extension pipe (E) and the liquid-side extension pipe (F), in view of a difference with respect to the normal cooling operation. If only an extension pipe portion (in this case, the liquid extension pipe (E) and the gas extension pipe (F)) is reused, the portion being included in a refrigeration system that uses mineral oil, such as mineral oil used for a CFC refrigerant or an HCFC refrigerant, as refrigerating machine oil, and the refrigeration system is changed to a refrigeration system that uses another refrigerant such as an HFC refrigerant (in this case, the outdoor unit D and the indoor units A, B, and C are renewed for the HFC refrigerant), this foreign-substance recovery operation is performed to remove the foreign substance mainly including the mineral oil and the deteriorated substance of the mineral oil, which adversely affect on the refrigeration cycle with the HFC refrigerant.
In this operation, the first opening and closing valve 10 and the second opening and closing valve 11 that are closed in the normal cooling operation are opened, and the second flow rate control device 6 is closed. Accordingly, the refrigerant does not flow to the second flow rate control device 6 as compared with the flow during the normal cooling operation. Instead of this, a liquid phase separated by the first gas-liquid separator 20 enters the pipe 7B of the double-pipe heat exchanger through the first opening and closing valve 10, the liquid phase is heated and evaporated in the pipe 7B, the gas and liquid are separated by the second gas-liquid separator 21, the refrigerant of a liquid phase or two phases flows to the foreign-substance recovery container 8 through the second opening and closing valve 11, and only the gas refrigerant is returned to the suction side of the compressor 1 through the first check valve 12.
As shown in Fig. 6, a primary portion of the foreign-substance capturing means may be configured of a simple structure (the second gas-liquid separator 21, the second opening and closing valve 11, and the foreign-substance recovery container 8), and may be created with a low cost.
Described next is movement of the refrigerant during the foreign-substance recovery operation and mineral oil that initially remains in a pipe extending from the third flow rate control device 27 to the four-way valve 2 through the first flow rate control devices 4A, 4B, and 4C.
In the foreign-substance recovery operation, the indoor units 4A to 4C are partly operated, for example, only the use-side heat exchanger 5A is operated. The first flow rate control device 4A is full open, the first flow rate control devices 4B and 4C are full closed, the second flow rate control device 6 is full closed, and third flow rate control device 27 is operated similarly to normal cooling control. In this case, since the refrigerant output from the third flow rate control device 27 is not completely evaporated by the use-side heat exchanger 5A, the refrigerant becomes an annular two-phase refrigerant. The refrigerant reaches the first gas-liquid separator 20 through the four-way valve 2 while the refrigerant removes and flushes the mineral oil adhering to the pipe. From the first gas-liquid separator 20, the removed foreign substance and the liquid phase enter the pipe 7B of the double-pipe heat exchanger through the first opening and closing valve 10, the refrigerant is slightly evaporated in the pipe 7B, then the refrigerant enters the second gas-liquid separator 21, and the liquid phase and the mineral oil remaining in the second gas-liquid separator 21 are recovered by the foreign-material recovery container 8. In this case, a single indoor unit is operated every constant time. After all indoor units are similarly individually operated, the normal cooling operation is performed for a short time, for example, 20 seconds. Hence, the mineral oil finally remaining in the pipe 7B of the double-pipe heat exchanger is recovered in the foreign-substance recovery container 8, then the compressor 1 is stopped, and then the first opening and closing valve 10 and the second opening and closing valve 11 are closed.
The first gas-liquid separator 20 is arranged at a higher position than the position of the second gas-liquid separator 21 so that the refrigerant flows from the first gas-liquid separator 20 to the second gas-liquid separator 21. Accordingly, the foreign substance can be further reliably recovered in the foreign-substance recovery container 8.
Also, the operation capacity of the indoor units 4A and 4B is determined to be an annular two-phase flow so that the mineral oil in the pipe can be recovered.
Also, to prevent the refrigerant in the path located downstream of the third flow rate control device 27 from flowing with difficulty in the form of annular two-phase flow and from being evaporated with difficulty in the low-pressure-side pipe 7B of the double-pipe heat exchanger 7 because the outside air is lowered, if the detected temperature of the fifth temperature detecting means 22 is 10 degrees C or lower, a third opening and closing valve 24 and a fourth opening and closing valve 25 are closed, so that the high pressure is increased. If the detected temperature of the fifth temperature detecting means 22 exceeds, for example, 10 degrees C, the third opening and closing valve 24 and the fourth opening and closing valve 25 are opened.
Also, to prevent the liquid refrigerant to be excessively increased in the foreign-substance recovery container 8, in the foreign-substance recovery operation, the opening degree of each of the flow- rate control devices 4A, 4B, and 4C of the indoor units being full open may be periodically alternately changed between the full open state and a normal operation opening degree.
Fig. 4 explains the flow of the foreign-substance recovery operation with a flowchart. Description is given below with reference to the flow in Fig. 4. After a replacement work for a heat source device or an indoor unit, the foreign-substance recovery operation is started (S1).
Then, the first opening and closing valve 10 and the second opening and closing valve 11 are opened (S2), and an indoor unit to be operated is determined (S3).
A constant-time operation is performed for each determined indoor unit (S4 to S7), and then, the normal cooling operation is performed for about 20 seconds (S8).
Then, the foreign-substance recovery operation is ended, and the compressor 1 is stopped (S9, S10). Then, the first opening and closing valve 10 and the second opening and closing valve 11 are closed (S11).

Embodiment 2

Fig. 5 is a refrigerant circuit diagram of a refrigeration cycle apparatus according to Embodiment 2 of this invention. As shown in Fig. 5, the liquid refrigerant separated from the first gas-liquid separator 20 and the recovered foreign-substance (the mineral oil etc.) may not pass through the double-pipe heat exchanger 7, but may directly flow into the foreign-substance recovery container 8. In this case, the first gas-liquid separator 20, the first opening and closing valve 10, and the foreign-substance recovery container 8 form a foreign-substance recovery refrigerant circuit.
However, in this case, the size of the foreign-substance recovery container 8 is preferably selected so as to allow the liquid refrigerant to be recovered therein. Alternatively, the refrigerant recovery amount of the foreign-substance recovery container 8 is preferably restricted by alternately periodically changing the opening degree of the flow rate control devices 4A, 4B, and 4C, the opening degree of which has been full open during the foreign-substance recovery operation, between the full open and the normal operation opening degree.
In any of the above-described embodiments, the accumulator 9 is provided between the compressor 1 and the use- side heat exchangers 4A, 4B, and 4C. In this case, if the entrance side of the foreign-substance recovery refrigerant circuit is connected with the inlet side of the accumulator 9 and if the exit side of the foreign-substance recovery refrigerant circuit is connected with the outlet side of the accumulator 9, the foreign substance can be further reliably recovered in the foreign-substance recovery container 8.

Reference Signs List

1: compressor, 2: four-way valve, 3A, 3B: heat-source-side heat exchanger, 4A, 4B, 4C: first flow rate control device (first expansion device), 5A, 5B, 5C: use-side heat exchanger, 6: second flow rate control device (second expansion device), 7: double-pipe heat exchanger (high-low pressure heat exchanger), 8: foreign-substance recovery container, 9: accumulator, 10: first opening and closing valve, 11: second opening and closing valve, 12: first check valve, 13: first pressure detecting means, 14: second pressure detecting means, 15: third pressure detecting means, 16: first temperature detecting means, 17: second temperature detecting means, 18A, 18B, 18C: third temperature detecting means, 19A, 19B, 19C: fourth temperature detecting means, 20: first gas-liquid separator, 21: second gas-liquid separator, 22: fifth temperature detecting means, 23: oil recovery unit, 24: third opening and closing valve, 25: fourth opening and closing valve, 26: second check valve, 27: third flow rate control device (third expansion device), 28: fifth opening and closing valve, 29: sixth opening and closing valve, A: indoor unit A, B: indoor unit B, C: indoor unit C, D: outdoor unit, E: liquid-side extension pipe, F: gas-side extension pipe

Claims

A refrigeration cycle apparatus including a main refrigerant circuit, through which a refrigerant circulates through a compressor, a heat-source-side heat exchanger, a first flow rate control device, and a use-side heat exchanger, the refrigeration cycle apparatus comprising:
a first gas-liquid separator; and a foreign-substance recovery container that recovers a foreign substance contained in the refrigerant, wherein a foreign-substance recovery refrigerant circuit that connects the first gas-liquid separator with the foreign-substance recovery container through a first passage opening and closing device is arranged between a suction side of the compressor and the use-side heat exchanger, in parallel with the main refrigerant circuit.
The refrigeration cycle apparatus of claim 1, wherein a low-pressure-side pipe of a high-low pressure heat exchanger, a second gas-liquid separator, and a second passage opening and closing device are connected in that order between the first passage opening and closing device and the foreign-substance recovery container.
The refrigeration cycle apparatus of claim 2, wherein a position of the first gas-liquid separator is higher than a position of the second gas-liquid separator.
The refrigeration cycle apparatus of claim 1 or 2,
wherein, if an accumulator is provided between the compressor and the use-side heat exchanger,
an entrance of the foreign-substance recovery refrigerant circuit is arranged at an inlet of the accumulator, and an exit of the foreign-substance recovery refrigerant circuit is arranged at an outlet of the accumulator.
The refrigeration cycle apparatus of any one of claims 1 to 4, wherein a refrigerant pipe that connects an outdoor unit including the compressor and the heat-source-side heat exchanger with an indoor unit including the use-side heat exchanger is the refrigerant pipe that connected a previous outdoor unit with a previous indoor unit provided before replacement to the outdoor unit and the indoor unit.
The refrigeration cycle apparatus of any one of claims 1 to 5, wherein a previous outdoor unit and a previous indoor unit before the replacement to the outdoor unit and the indoor unit use a CFC refrigerant or an HCFC refrigerant, and the outdoor unit and the indoor unit after the replacement use an HFC refrigerant.
The refrigeration cycle apparatus of any one of claims 1 to 6, wherein, during a foreign-substance recovery operation that uses the foreign-substance recovery refrigerant circuit, a capacity of the use-side heat exchanger is set so that the refrigerant directed from the use-side heat exchanger toward the compressor becomes an annular two-phase flow.