WO2012098582A1

WO2012098582A1 - Refrigeration cycle apparatus

Info

Publication number: WO2012098582A1
Application number: PCT/JP2011/000283
Authority: WO
Inventors: 嶋本　大祐; 森本　修
Original assignee: 三菱電機株式会社
Priority date: 2011-01-20
Filing date: 2011-01-20
Publication date: 2012-07-26
Also published as: EP2667120A4; EP2905562B1; EP2667120A1; EP2667120B1; JP5762441B2; EP2905562A1; JPWO2012098582A1

Abstract

A refrigeration cycle apparatus comprising a main refrigerant circuit through which refrigerant circulates between a compressor (1), a heat-source-unit-side heat exchanger (3), a first flow rate control device (4), and a usage-side heat exchanger (5); wherein the apparatus has a first gas-liquid separator (20) and a contaminant recovery container (8) for recovering contaminants contained in the refrigerant, and a contaminant recovery refrigerant circuit that connects the first gas-liquid separator (20) and the contaminant recovery container (8) via a first flow channel opening/closing device (10) is installed in parallel with the main refrigerant circuit between the usage-side heat exchanger (5) and the intake side of the compressor (1).

Description

Refrigeration cycle equipment

In the present invention, an extended piping portion of a refrigeration cycle apparatus that uses mineral oil such as that used in CFC refrigerant or HCFC refrigerant as refrigeration oil is reused in a refrigeration cycle apparatus that uses another refrigerant such as an HFC refrigerant system. In this case, the present invention relates to a refrigeration cycle apparatus provided with a means capable of physically washing foreign matter centered on mineral oil and mineral oil remaining in the extension pipe portion with a refrigerant.

The following are known as conventional extension pipe cleaning techniques. Remove the air conditioner that needs to be replaced and the use-side heat exchanger connected to the existing piping, and connect the cleaning device and bypass pipe to the existing piping. After connection, the entire refrigeration cycle is evacuated and then filled with an appropriate amount of R407C. Then the compressor is operated. The high-temperature and high-pressure gas refrigerant discharged from the compressor first passes through the oil separator. At this stage, the refrigeration oil discharged from the compressor together with the gas refrigerant is separated by the oil separator and returned to the suction side of the compressor. The high-temperature and high-pressure gas refrigerant then passes through the four-way valve, and the gas is partially cooled by the high- and low-pressure heat exchanger to become liquid and become high-pressure gas-liquid two-phase refrigerant. The high-pressure gas-liquid two-phase refrigerant passes through the existing pipe, the bypass pipe, and the existing pipe, and then is decompressed to a low-pressure gas-liquid two-phase refrigerant by the decompression device. After that, it is heated by a high / low pressure heat exchanger to become a low pressure gas. Next, it passes through the separation device, and at this time, the mineral oil washed in the existing piping is separated, and the mineral oil is held in the separation device. After the temperature of the low-pressure refrigerant gas is lowered by the heat source side heat exchanger so that the discharge temperature of the compressor does not become too high, the refrigerant gas is sucked into the compressor through a four-way valve and an accumulator (Patent Document 1).

Japanese Patent No. 3521820

In the conventional technique such as Patent Document 1, since the foreign matter capturing means that contributes to the cleaning of foreign matter such as mineral oil is on the low pressure side of the cooling operation, performance degradation due to pressure loss is likely to occur. In addition, the structure of the air conditioner having a normal refrigeration cycle has been greatly changed, and there has been a problem that it is difficult to standardize or to make an option for foreign matter supplementing means. Moreover, since heat exchange is performed between the main pipes, the heat exchanger in that portion becomes large and expensive. The present invention aims to solve at least one of these problems.

A refrigeration cycle apparatus according to a first aspect of the present invention includes a main refrigerant circuit in which a refrigerant circulates between a compressor, a heat source apparatus side heat exchanger, a first flow rate control apparatus, and a use side heat exchanger. A refrigeration cycle apparatus comprising: a first gas-liquid separator; and a foreign material recovery container for recovering the foreign material contained in the refrigerant, and the space between the first gas-liquid separator and the foreign material recovery container. A foreign matter recovery refrigerant circuit connected via a first flow path opening / closing device is installed in parallel to the main refrigerant circuit between the suction side of the compressor and the use side heat exchanger. .

In addition, the low pressure side pipe of the high / low pressure heat exchanger, the second gas-liquid separator, and the second flow path opening / closing device are sequentially connected between the first flow path opening / closing device and the foreign matter collection container. Is more preferable. In this case, it is preferable that the position of the first gas-liquid separator is higher than that of the second gas-liquid separator.

In addition, when an accumulator is provided between the compressor and the use side heat exchanger, the inlet of the foreign substance recovery refrigerant circuit is connected to the inlet of the accumulator, and the outlet of the foreign substance recovery refrigerant circuit is connected to the outlet of the accumulator. Is preferred.

The refrigeration cycle apparatus configured as described above has a small difference between the refrigeration cycle having no foreign matter recovery refrigerant circuit and the refrigerant circuit configuration, and therefore, it is easy to add the foreign matter recovery refrigerant circuit and an inexpensive refrigerant circuit can be realized.

FIG. 3 is a refrigerant circuit diagram of the refrigeration cycle apparatus in Embodiment 1 of the present invention. The flowchart of the refrigerant | coolant of the air_conditionaing | cooling operation state in Embodiment 1 of this invention. The flowchart of the refrigerant | coolant of the heating operation state in Embodiment 1 of this invention. The flowchart figure of the washing | cleaning control method of the extension piping of Embodiment 1 of this invention. The refrigerant circuit figure of the refrigerating-cycle apparatus in Embodiment 2 of this invention. The block diagram which shows an example of the foreign material supplementation means in Embodiment 1 of this invention.

Embodiment 1
1 is a refrigerant circuit diagram of a refrigeration cycle apparatus (air conditioner) according to Embodiment 1 of the present invention. The main refrigerant circuit of this air conditioner includes a compressor 1, a four-way valve 2 as a flow path switching valve, heat source

side heat exchangers

3A and 3B, and first flow

rate control devices

4A and 4B for controlling the refrigerant flow rate of the refrigerant circuit. , 4C, use

side heat exchangers

5A, 5B, 5C, an accumulator 9, and the like. The accumulator 9 may be provided as necessary.

The series circuit of the first flow control device 4A and the use side heat exchanger 5A, the first flow control device 4B and the use side heat exchanger 5B, and the first flow control device 4C and the use side heat exchanger 5C are as follows. These are constituent elements of the indoor unit A, the indoor unit B, and the indoor unit C, and are connected in parallel. The number of indoor units is not particularly limited.
An oil recovery unit 23 is provided between the compressor 1 and the four-way valve 2, and a first air is provided between the four-way valve 2 and the accumulator 9 (the compressor 1 when there is no accumulator 9). A liquid separator 20 is provided.

Double pipe heat exchange which is a high-low pressure heat exchanger having a high-pressure side pipe 7A and a low-pressure side pipe 7B between the heat source

side heat exchangers

3A, 3B and the first flow

rate control devices

4A, 4B, 4C. A vessel 7 is provided. Between the double pipe heat exchanger 7 and the first flow

rate control devices

4A, 4B, 4C, a third flow rate control device 27 for controlling the downstream pressure during the cooling operation, and a fifth on-off valve 28 is provided. Furthermore, a sixth open / close valve 29 is provided between the use

side heat exchangers

5A, 5B, 5C and the four-way valve 2.

The pipe connecting the fifth on-off valve 28 and the first

flow control devices

4A, 4B, 4C is called a liquid side extension pipe (E), and the sixth on-off valve 29 and the use

side heat exchangers

5A, 5B, The pipe connecting 5C is referred to as a gas side extension pipe (F).
The refrigerant circulates in the main refrigerant circuit configured as described above according to the direction of the four-way valve 2 switched according to the cooling operation or the heating operation.

In this air conditioner, the second flow rate control device 6, the low pressure side pipe 7B of the double pipe heat exchanger 7, the second gas-liquid separation device 21, and the second opening / closing device which is the second flow path opening / closing device. A first bypass circuit is provided in which the valve 11, the foreign material recovery container 8, and the first check valve 12 are connected in series. The first bypass circuit branches from between the heat source side heat exchanger 3 and the third flow control device 27, and the compressor 1 and the accumulator 9 (the first gas-liquid separator 20 in the absence of the accumulator 9). ) Are connected between the refrigerant pipes.
Further, the accumulator 9 and the first gas-liquid separator 20 are connected to the second gas-liquid separator 21 via a second bypass circuit including a second check valve 26.
Furthermore, between the second flow rate control device 6 and the low-pressure side pipe 7B of the double-pipe heat exchanger 7, the first gas-liquid separation device 20 is a first opening / closing device that is a first channel opening / closing device. A third bypass circuit including the valve 10 is connected.

And the 1st gas-liquid separation apparatus 20, the 1st on-off valve 10, the low pressure side piping 7B of the double pipe heat exchanger 7, the 2nd gas-liquid separation apparatus 21, the 2nd on-off valve 11, and foreign material collection | recovery The container 8 constitutes a foreign matter collecting refrigerant circuit as foreign matter collecting means for collecting foreign matters in the refrigerant.

Note that the first check valve 12 is the forward direction toward the compressor 1, and the second check valve 26 is the forward direction toward the accumulator 9.
Further, the first gas-liquid separation device 20 is configured to flow a liquid phase to the first on-off valve 10 side and a gas phase to the accumulator 9 side.
Further, the second gas-liquid separation device 21 is configured to flow a liquid phase to the second on-off valve 11 side and a gas phase to the second check valve 26 side.

The first pressure detection means 13 and the second pressure detection means 14 are connected to the discharge side and the suction side of the compressor 1, respectively.
And the 3rd pressure detection means 15 is connected to the middle of piping which connects the 3rd flow control device 27 and the 5th on-off valve 28. FIG.
Furthermore, the first temperature detection means 16 is provided on the discharge side of the compressor 1, and the second temperature detection means 17 is provided between the low pressure side pipe 7 </ b> B of the double pipe heat exchanger 7 and the second gas-liquid separation device 21. Between the pipes.

The third temperature detection means 18A, 18B, 18C are connected between the first

flow control devices

4A, 4B, 4C and the use

side heat exchangers

5A, 5B, 5C.
The fourth temperature detection means 19A, 19B, 19C are connected to each use side heat exchanger side between the use

side heat exchangers

5A, 5B, 5C and the gas side extension pipe (F).
Furthermore, the 5th temperature detection means 22 is provided in order to detect outdoor temperature.
In addition, the element in the wavy line D of FIG. 1 represents the component of the outdoor unit (D).

Next, the flow of the refrigerant in the refrigerant circuit shown in FIG. 1 will be described with reference to FIGS. As shown in FIG. 2, in the normal cooling operation, the refrigerant containing the refrigerating machine oil discharged from the compressor 1 separates the refrigerating machine oil in the oil recovery unit 23, and passes through the four-way valve 2 to perform heat exchange on the rear heat source machine side Heat is exchanged with air in the vessel 3 to be condensed and liquefied. Thereafter, the refrigerant is further cooled by the high-pressure side pipe 7A of the double-tube heat exchanger 7, and the cooled refrigerant is partially opened by the third flow control device 27 after the pressure is adjusted. 5 and enters the first

flow control devices

4A, 4B, 4C of the indoor unit via the liquid side extension pipe (E). The refrigerant depressurized by the first

flow control devices

4A, 4B, 4C exchanges heat with air in the use

side heat exchangers

5A, 5B, 5C to be evaporated and gasified, and the liquid side extension pipe (F) is opened. After passing through the on-off valve 29 and the four-way valve 2, the first gas-liquid separator 20 and the accumulator 9 are returned to the suction side of the compressor 1.

On the other hand, a part of the refrigerant separated after passing through the high pressure side pipe 7A of the double pipe heat exchanger 7 is depressurized by the second flow control device 6, and high pressure is given by the low pressure side pipe 7B of the double pipe heat exchanger. It evaporates by exchanging heat with the side pipe 7 </ b> A, and flows into the pipe connecting the first gas-liquid separator 20 and the accumulator 9 via the second gas-liquid separator 21 and the second check valve 26. During normal cooling, the first on-off valve 10 and the second on-off valve 11 are closed, and the first gas-liquid separation device 20 to the first on-off valve 10 and the second gas-liquid separation. The refrigerant does not flow from the device 21 to the second on-off valve 11.

The first

flow control devices

4A, 4B, 4C control the difference between the fourth

temperature detection devices

19A, 19B, 19C and the third

temperature detection devices

18A, 18B, 18C to a constant numerical value, for example, “2”. The second flow rate control device 6 is the difference between the saturation temperatures of the second temperature detection device 17 and the second pressure detection device 14, for example, “5”, and the third flow rate control device 27 is the third pressure detection device 15. For example, “3.0 MPa”. In addition, the control value by the 3rd pressure detection apparatus 15 turns into a value set below the allowable value of piping.

In heating operation, there is no mineral oil recovery operation, and only normal heating operation is performed. As shown in FIG. 3, the refrigerant containing the refrigerating machine oil discharged from the compressor 1 separates the refrigerating machine oil in the oil recovery unit 23, and the four-way valve 2, the opened sixth on-off valve 29, and the liquid side extension pipe After passing through (F), heat is exchanged with air in the use

side heat exchangers

5A, 5B, and 5C to be condensed and liquefied, and the pressure is reduced in the first flow

rate control devices

4A, 4B, and 4C to be in a two-phase state. The refrigerant in the two-phase state passes through the gas side extension pipe (E), the opened fifth on-off valve 28, the fully opened third flow rate control device 27, the pipe 7A of the double pipe heat exchanger, and the heat source After exchanging heat with air in the machine-side heat exchanger 3 and evaporating gas, it returns to the suction side of the compressor 1 via the four-way valve 2. In addition, the 2nd flow control apparatus 6 is fully closed, and a refrigerant | coolant does not flow into the piping 7B of a double tube heat exchanger. Further, by controlling the first flow

rate control devices

4A, 4B, and 4C, subcooling at the outlet portions of the use

side heat exchangers

5A, 5B, and 5C can be controlled. The subcools at the outlets are values obtained by subtracting the detected temperatures of the second temperature detecting means 18A, 18B, and 18C from the saturation temperature of the detected pressure of the first pressure detecting means 13.

Next, the flow of the refrigerant during the foreign matter recovery operation for recovering the foreign matter centered on mineral oil and mineral oil remaining in the gas side extension pipe (E) and the liquid side extension pipe (F) will be explained by the difference from the normal cooling operation. To do. This foreign matter recovery operation is an extension pipe portion (here, a liquid extension pipe (E) and a gas extension pipe (F)) in a refrigeration system that uses mineral oil such as that used in CFC refrigerant or HCFC refrigerant as refrigeration oil. ) Only to recycle and change to a refrigeration system that uses another refrigerant such as HFC refrigerant (here, the outdoor unit D and the indoor units A, B, and C are renewed for HFC refrigerant) Foreign matters such as mineral oil and deteriorated mineral oil that adversely affect the refrigeration cycle of the HFC refrigerant are excluded from the refrigeration cycle.

In this operation, the first on-off valve 10 and the second on-off valve 11 that were normally closed during the cooling operation are opened, and the second flow control device 6 is closed. Thereby, the refrigerant does not flow to the second flow rate control device 6 with respect to the flow of the normal cooling operation, but instead the liquid phase separated by the first gas-liquid separation device 20 is the first on-off valve 10. And then enters the pipe 7B of the double-pipe heat exchanger, is heated and evaporated there, and is separated into gas and liquid by the second gas-liquid separation device 21, so that the refrigerant in the liquid phase or the two-phase is second closed. It flows into the foreign material collection container 8 through the valve 11, and only the gas refrigerant returns to the suction portion of the compressor 1 through the first check valve 12.
As shown in FIG. 6, the main part of the foreign matter capturing means can be composed of a simple structure (second gas-liquid separator 21, second on-off valve 11 and foreign matter collection container 8), and can be produced at low cost. It becomes.

Next, the movement of the refrigerant during the foreign substance recovery operation and the mineral oil staying in the initial state in the pipe from the third flow control device 27 to the four-way valve 2 via the first

flow control devices

4A, 4B, 4C will be described. .
During the foreign matter collecting operation, the indoor units 4A to 4C are partially operated, for example, only the use-side heat exchanger 5A is operated, the first flow control device 4A is fully opened, and the first

flow control devices

4B and 4C are The second flow rate control device 6 is fully closed, and the third flow rate control device 27 is operated in the same manner as the normal cooling control. In this case, the refrigerant that has exited the third flow control device 27 cannot evaporate in the use-side heat exchanger 5A. Then, the first gas-liquid separator 20 is reached. In the first gas-liquid separator 20, the removed foreign matter and the liquid phase enter the pipe 7 </ b> B of the double-pipe heat exchanger through the first on-off valve 10, and after evaporating the refrigerant slightly there, The gas-liquid separator 21 is entered, and the remaining liquid phase and mineral oil are recovered in the foreign material recovery container 8. In this case, one indoor unit is operated at regular intervals, and all the indoor units are individually operated in the same manner, and finally the normal cooling operation is performed for a short time, for example, 20 seconds. After the mineral oil staying in the pipe 7B of the heavy pipe heat exchanger is collected in the foreign matter collection container 8, the compressor 1 is stopped, and then the first on-off valve 10 and the second on-off valve 11 are closed.

Note that the position of the first gas-liquid separator 20 is set higher than that 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. Thereby, a foreign material can be secured in the foreign material collection container 8 more reliably.
The operating capacity of the indoor units 4A to 4B is set so as to be an annular two-phase flow that can recover the mineral oil in the pipe.
Moreover, it is difficult for the refrigerant after the third flow rate control device 27 to flow in an annular two-phase flow and the refrigerant is less likely to evaporate in the low-pressure side pipe 7B of the double-tube heat exchanger 7 due to a decrease in outside air. Therefore, when the fifth temperature detection means 22 becomes 10 ° C. or less, for example, the third on-off valve 24 and the fourth on-off valve 25 are closed to increase the high pressure. In addition, when the 5th temperature detection means 22 exceeds 10 degreeC, for example, the 3rd on-off valve 24 and the 4th on-off valve 25 are opened.
Further, in order to prevent the liquid refrigerant from increasing in the foreign matter recovery container 8, in the foreign matter recovery operation, the openings of the

flow control devices

4A, 4B, and 4C of the indoor units that are fully opened are periodically alternately opened to the normal operation. It may be varied.

FIG. 4 is a flowchart illustrating the flow of these foreign substance recovery operations. Hereinafter, description will be made along the flow of FIG. After completion of the replacement of the heat source unit and the indoor unit, the foreign matter recovery operation is started (S1).
Next, the first on-off valve 10 and the second on-off valve 11 are opened (S2), and the indoor unit to be operated is determined (S3).
Then, after performing the operation for a certain time for each determined indoor unit (S4 to S7), the normal cooling operation is performed for about 20 seconds (S8).
Thereafter, the foreign matter collecting operation is terminated and the compressor 1 is stopped (S9, S10). Thereafter, the first on-off valve 10 and the second on-off valve 11 are closed (S11).

Embodiment 2
FIG. 5 is a refrigerant circuit diagram of the refrigeration cycle apparatus in Embodiment 2 of the present invention. As shown in FIG. 5, the liquid refrigerant separated from the first gas-liquid separator 20 and the collected foreign matter (mineral oil or the like) are caused to flow directly into the foreign matter collection container 8 without passing through the double pipe heat exchanger 7. Also good. In this case, the first gas-liquid separation device 20, the first on-off valve 10, and the foreign material collection container 8 constitute a foreign material collection refrigerant circuit.
However, in this case, the foreign matter collection container 8 is selected to have a size that allows liquid refrigerant or the opening degree of the

flow control devices

4A, 4B, and 4C of the indoor units that are fully opened during the foreign matter collection operation is periodically set. It is preferable to suppress the refrigerant recovery amount in the foreign material recovery container 8 by alternately changing the full opening and the normal operation opening degree.

In each of the above embodiments, an example in which the accumulator 9 is provided between the compressor 1 and the use

side heat exchangers

4A, 4B, and 4C has been shown. Is connected to the inlet side of the accumulator 9 and the outlet side of the foreign material recovery refrigerant circuit is connected to the outlet side of the accumulator 9, so that the foreign material can be more reliably secured in the foreign material recovery container 8.

1: compressor, 2: four-way valve, 3A, 3B: heat source side heat exchanger, 4A, 4B, 4C: first flow control device (first expansion device), 5A, 5B, 5C: use side heat Exchanger, 6: second flow rate control device (second throttle device), 7: double pipe heat exchanger (high / low pressure heat exchanger), 8: foreign matter collection container, 9: accumulator, 10: first On-off valve, 11: second on-off valve, 12: first check valve, 13: first pressure detection means, 14: second pressure detection means, 15: third pressure detection means, 16: first 1 temperature detection means, 17: second temperature detection means, 18A, 18B, 18C: third temperature detection means, 19A, 19B, 19C: fourth temperature detection means, 20: first gas-liquid separator , 21: second gas-liquid separator, 22: fifth temperature detecting means, 23: oil recovery device, 24: third on-off valve, 25: fourth Closed valve, 26: second check valve, 27: third flow control device (third throttling device), 28: fifth open / close valve, 29: sixth open / close valve, A: indoor unit A, B: Indoor unit B, C: Indoor unit C, D: Outdoor unit, E: Liquid side extension piping, F: Gas side extension piping.

Claims

A refrigeration cycle apparatus including a main refrigerant circuit in which a refrigerant circulates between a compressor, a heat source apparatus side heat exchanger, a first flow control device, and a use side heat exchanger,
A first gas-liquid separator; and a foreign-material recovery container that recovers foreign substances contained in the refrigerant. A first flow path opening / closing device is provided between the first gas-liquid separator and the foreign-material recovery container. A refrigeration cycle apparatus in which a foreign substance recovery refrigerant circuit connected via the compressor is installed in parallel to the main refrigerant circuit between the suction side of the compressor and the use side heat exchanger.
A low-pressure side pipe of a high-low pressure heat exchanger, a second gas-liquid separator, and a second flow-path opening / closing device are sequentially connected between the first flow-path opening / closing device and the foreign matter collection container. Item 2. The refrigeration cycle apparatus according to Item 1.
The refrigeration cycle apparatus according to claim 2, wherein the position of the first gas-liquid separator is higher than that of the second gas-liquid separator.
In an accumulator provided between the compressor and the use side heat exchanger,
3. The refrigeration cycle apparatus according to claim 1, wherein an inlet of the foreign material recovery refrigerant circuit is disposed at an inlet of the accumulator, and an outlet of the foreign material recovery refrigerant circuit is disposed at an outlet of the accumulator.
Before the refrigerant pipe connecting the outdoor unit having the compressor and the heat source side heat exchanger and the indoor unit having the use side heat exchanger is replaced with the outdoor unit and the indoor unit The refrigeration cycle apparatus according to any one of claims 1 to 4, wherein the refrigeration cycle apparatus is a refrigerant pipe connecting the outdoor unit and the indoor unit.
The CFC refrigerant or the HCFC refrigerant is used in the outdoor unit and the indoor unit before the replacement to the outdoor unit and the indoor unit, and the HFC refrigerant is used in the outdoor unit and the indoor unit after the replacement. 6. The refrigeration cycle apparatus according to any one of 1 to 5.
2. The capacity of the use side heat exchanger is set so that refrigerant flowing from the use side heat exchanger to the compressor becomes an annular two-phase flow during the foreign substance collection operation using the foreign substance collection refrigerant circuit. 7. The refrigeration cycle apparatus according to any one of items 1 to 6.