KR102240071B1 - Air Conditioner - Google Patents

Abstract

The present invention relates to an air conditioner for injecting a refrigerant into a compressor in two stages using a gas-liquid separator. An air conditioner according to an embodiment of the present invention includes: a compressor for compressing a refrigerant; A condenser for condensing the refrigerant compressed by the compressor; A first main expansion valve for expanding the refrigerant condensed in the condenser; A first injection module for separating the refrigerant expanded by the first main expansion valve into a gaseous refrigerant and a liquid refrigerant, and expanding the separated gaseous refrigerant and injecting the refrigerant into the compressor; An intermediate expansion valve for expanding the liquid refrigerant separated from the first injection module; A second injection module for separating the refrigerant expanded by the intermediate expansion valve into a gaseous refrigerant and a liquid refrigerant, and expanding the separated gaseous refrigerant and injecting the refrigerant into the compressor; A second main expansion valve for expanding the liquid refrigerant separated from the second injection module; And an evaporator for evaporating the refrigerant expanded in the second main expansion valve.

Description

Air Conditioner {Air Conditioner}

The present invention relates to an air conditioner, and more particularly, to an air conditioner that injects a refrigerant into a compressor in two stages using a gas-liquid separator.

In general, an air conditioner is a device that cools or heats an indoor space using a refrigeration cycle including a compressor, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger. That is, it may be composed of an air conditioner that cools the room and a heater that heats the room. In addition, it may be configured with an air conditioner for both cooling and heating that cools or heats the room.

Such an air conditioner improves efficiency by injecting a portion of condensed refrigerant into a compressor during heating or cooling. For high efficiency, two-stage injection is required in which refrigerant is simultaneously injected into the high-pressure side and the low-pressure side of the compressor.

Registered Patent Publication No. 10-0310411 Unexamined Patent Publication No. 10-2011-0054816

The problem to be solved by the present invention is to provide an air conditioner capable of injecting a refrigerant into a compressor in two stages using a gas-liquid separator.

The problems of the present invention are not limited to the problems mentioned above, and other problems that are not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve the above object, an air conditioner according to an embodiment of the present invention includes a compressor for compressing a refrigerant; A condenser for condensing the refrigerant compressed by the compressor; A first main expansion valve for expanding the refrigerant condensed in the condenser; A first injection module for separating the refrigerant expanded by the first main expansion valve into a gaseous refrigerant and a liquid refrigerant, and expanding the separated gaseous refrigerant and injecting the refrigerant into the compressor; An intermediate expansion valve for expanding the liquid refrigerant separated from the first injection module; A second injection module for separating the refrigerant expanded by the intermediate expansion valve into a gaseous refrigerant and a liquid refrigerant, and expanding the separated gaseous refrigerant and injecting the refrigerant into the compressor; A second main expansion valve for expanding the liquid refrigerant separated from the second injection module; And an evaporator for evaporating the refrigerant expanded in the second main expansion valve.

Details of other embodiments are included in the detailed description and drawings.

According to the air conditioner of the present invention, one or more of the following effects are provided.

First, there is an advantage in that performance can be improved by injecting refrigerant into the compressor in two stages through the configuration and control of a gas-liquid separator and an expansion valve for injection.

Second, there is also an advantage of improving reliability by properly controlling the expansion valve for injection.

The effects of the present invention are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

1 is a block diagram of an air conditioner according to an embodiment of the present invention.
2 is a block diagram of an air conditioner according to an embodiment of the present invention.
3 is a diagram showing a pressure-enthalpy diagram (hereinafter, a Ph diagram) when an air conditioner is operated according to an embodiment of the present invention.

Advantages and features of the present invention, and a method of achieving them will become apparent with reference to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in a variety of different forms, and only these embodiments make the disclosure of the present invention complete, and are common knowledge in the technical field to which the present invention pertains. It is provided to completely inform the scope of the invention to those who have, and the invention is only defined by the scope of the claims. The same reference numerals refer to the same elements throughout the specification.

Hereinafter, the present invention will be described with reference to the drawings for explaining an air conditioner according to embodiments of the present invention.

1 is a block diagram of an air conditioner according to an embodiment of the present invention.

An air conditioner according to an embodiment of the present invention includes a compressor 110 that compresses a refrigerant, a condenser 120 that condenses the refrigerant compressed in the compressor 110, and expands the refrigerant condensed in the condenser 120. A first injection module for separating the refrigerant expanded from the first main expansion valve 140 and the first main expansion valve 140 into a gaseous refrigerant and a liquid refrigerant, and injecting the separated gaseous refrigerant into the compressor 110 ( 170), the intermediate expansion valve 190 for expanding the liquid refrigerant separated from the first injection module 170, and the refrigerant expanded by the intermediate expansion valve 190 are separated into a gas phase refrigerant and a liquid refrigerant, and the separated gas phase refrigerant A second injection module 180 that expands and injects into the compressor 110, a second main expansion valve 150 that expands the liquid refrigerant separated from the second injection module 180, and a second main expansion valve ( It includes an evaporator 130 for evaporating the refrigerant expanded in 150).

The compressor 110 compresses the incoming low temperature and low pressure refrigerant into a high temperature and high pressure refrigerant. The compressor 110 may have various structures, and may be a reciprocating compressor using a cylinder and a piston, or a scroll compressor using an orbiting scroll and a fixed scroll. In this embodiment, the compressor 110 is a scroll compressor.

The compressor 110 includes a first inlet port 111 through which the refrigerant evaporated from the evaporator 130 flows into, and a second inlet port 112 through which the refrigerant evaporated from the injection module 180 flows into It includes an inlet port 113 and a discharge port 114 through which the compressed refrigerant is discharged.

It is preferable that the second inlet port 112 is formed on the low pressure side of the compression chamber where the refrigerant is compressed by the compressor 110 and the third inlet port 113 is formed on the high pressure side of the compression chamber of the compressor 110.

The high pressure side of the compressor 110 is a portion having a relatively lower temperature and pressure than the low pressure side of the compressor 110. The low pressure side of the compressor 110 is a portion close to the first inlet port 111 in the compression chamber, and the high pressure side is a portion close to the discharge port 114. The refrigerant introduced into the first inlet port 111 of the compressor 110 flows into the compression chamber, passes through the low pressure side, passes through the high pressure side, and is discharged to the discharge port 114.

The compressor 110 compresses the refrigerant flowing into the first inlet port 111 in a compression chamber and merges with the refrigerant flowing into the second inlet port 112 formed on the low pressure side of the compression chamber to compress it. The compressor 110 compresses the confluent refrigerant, joins the refrigerant flowing into the third inlet port 113 formed on the high-pressure side of the compression chamber, and compresses it. The compressor 110 compresses the joined refrigerant and discharges it to the discharge port 114.

The condenser 120 is connected to the compressor 110 to condense the refrigerant compressed by the compressor 110. When the air conditioner is a cooler that cools the room, the condenser 120 is an outdoor heat exchanger that is disposed outdoors to heat exchange the outdoor air with the refrigerant. When the air conditioner is a heater that heats the room, the condenser 120 is disposed indoors. It is preferable that it is an indoor heat exchanger that exchanges heat between indoor air and refrigerant.

The condenser 120 is connected to the first main expansion valve 140, and the refrigerant condensed in the condenser 120 flows into the first main expansion valve 140.

The first main expansion valve 140 is connected to the condenser 120 to expand the refrigerant condensed in the condenser 120. The first main expansion valve 140 is disposed between the condenser 120 and the first injection module 170. The first main expansion valve 140 is connected to the first injection module 170 so that the refrigerant expanded in the first main expansion valve 140 flows into the first injection module 170.

The first injection module 170 is connected to the first main expansion valve 140 to separate the refrigerant expanded in the first main expansion valve 140 into a gaseous refrigerant and a liquid refrigerant, and expand the separated gaseous refrigerant to expand the compressor 110 ) To the high pressure side.

The first injection module 170 is connected to the third inlet port 113 of the compressor 110, the first main expansion valve 140 and the intermediate expansion valve 190.

The refrigerant separated from the first injection module 170 and expanded is injected into the high-pressure side of the compressor 110 through the third inlet port 113. The liquid refrigerant separated from the first injection module 170 flows into the intermediate expansion valve 190.

The first injection module 170 expands the first injection gas-liquid separator 171 that separates the flowing refrigerant into a gas phase refrigerant and a liquid refrigerant, and the gas-phase refrigerant separated from the first injection gas-liquid separator 171 and injects it into a compressor. It includes a first injection expansion valve (172).

The first injection gas-liquid separator 171 is connected to the first main expansion valve 140 to separate the refrigerant expanded by the first main expansion valve 140 into a gas phase refrigerant and a liquid refrigerant. The first injection gas-liquid separator 171 is connected to the first main expansion valve 140, the first injection expansion valve 172 and the intermediate expansion valve 190.

The gaseous refrigerant separated by the first injection gas-liquid separator 171 is introduced into the first injection expansion valve 172. The liquid refrigerant separated by the first injection gas-liquid separator 171 is introduced into the intermediate expansion valve 190.

The first injection expansion valve 172 is connected to the first injection gas-liquid separator 171 to expand the gaseous refrigerant separated from the first injection gas-liquid separator 171. The first injection expansion valve 172 is connected to the first injection gas-liquid separator 171 and the third inlet port 113 of the compressor 110. The refrigerant expanded by the first injection expansion valve 172 is injected into the high-pressure side of the compressor 110 through the third inlet port 113.

The intermediate expansion valve 190 is connected to the first injection module 170 to expand the liquid refrigerant separated from the first injection module 170. The intermediate expansion valve 190 is disposed between the first injection module 170 and the second injection module 180. The intermediate expansion valve 190 is connected to the first injection gas-liquid separator 171 and the second injection gas-liquid separator 181. The refrigerant expanded by the intermediate expansion valve 190 flows into the second injection module 180.

The second injection module 180 is connected to the intermediate expansion valve 190 to separate the refrigerant expanded in the intermediate expansion valve 190 into a gaseous refrigerant and a liquid refrigerant, and expand the separated gaseous refrigerant to expand the low pressure side of the compressor 110. To inject.

The second injection module 180 is connected to the second inlet port 112, the intermediate expansion valve 190, and the second main expansion valve 150 of the compressor 110.

The refrigerant separated from the second injection module 180 and expanded is injected into the low pressure side of the compressor 110 through the second inlet port 112. The liquid refrigerant separated by the second injection module 180 is introduced into the second main expansion valve 150.

The second injection module 180 expands the second injection gas-liquid separator 181 for separating the flowing refrigerant into a gaseous refrigerant and a liquid refrigerant, and the gaseous refrigerant separated by the second injection gas-liquid separator 181 and injects it into a compressor. It includes a second injection expansion valve (182).

The second injection gas-liquid separator 181 is connected to the intermediate expansion valve 190 to separate the refrigerant expanded by the intermediate expansion valve 190 into a gas phase refrigerant and a liquid refrigerant. The second injection gas-liquid separator 181 is connected to the intermediate expansion valve 190, the second injection expansion valve 182 and the second main expansion valve 150.

The gaseous refrigerant separated by the second injection gas-liquid separator 181 flows into the second injection expansion valve 182. The liquid refrigerant separated by the second injection gas-liquid separator 181 flows into the second main expansion valve 150.

The second injection expansion valve 182 is connected to the second injection gas-liquid separator 181 to expand the gaseous refrigerant separated from the second injection gas-liquid separator 181. The second injection expansion valve 182 is connected to the second injection gas-liquid separator 181 and the second inlet port 112 of the compressor 110. The refrigerant expanded by the second injection expansion valve 182 is injected into the low pressure side of the compressor 110 through the second inlet port 112.

The second main expansion valve 150 is connected to the second injection module 180 to expand the liquid refrigerant separated from the second injection module 180. The second main expansion valve 150 is disposed between the second injection module 180 and the evaporator 130. The second main expansion valve 150 is connected to the second injection gas-liquid separator 181 and the evaporator 130. The refrigerant expanded in the second main expansion valve 150 flows into the evaporator 130.

The evaporator 130 is provided between the second main expansion valve 150 and the compressor 110 to evaporate the refrigerant expanded by the second main expansion valve 150. When the air conditioner is a cooler that cools the room, the evaporator 130 is an indoor heat exchanger that is disposed indoors to exchange heat between indoor air and refrigerant. When the air conditioner is a heater that heats the room, the evaporator 130 is placed outdoors. It is preferable that it is an outdoor heat exchanger for exchanging outdoor air with a refrigerant.

The evaporator 130 is connected to the first inlet port 111 of the compressor 110, and the refrigerant evaporated in the evaporator 130 flows into the compressor 110 through the first inlet port 111.

2 is a block diagram of an air conditioner according to an embodiment of the present invention.

Referring to FIG. 2, the air conditioner according to an embodiment of the present invention includes a control unit 10 for controlling the air conditioner, and a temperature of a refrigerant that is condensed in the condenser 120 and introduced into the first main expansion valve 140. A first intermediate temperature sensor 12 that measures the temperature, a second intermediate temperature sensor 13 that measures the temperature of the refrigerant that is separated from the first injection module 170 and introduced into the intermediate expansion valve 190, and a second It includes a third intermediate temperature sensor 14 that is separated from the injection module 180 and measures the temperature of the refrigerant flowing into the second main expansion valve 150.

The controller 10 controls the operation of the air conditioner, and includes a compressor 110, a first main expansion valve 140, a second main expansion valve 150, a first injection expansion valve 172, and a second injection. The expansion valve 182 and the intermediate expansion valve 190 are controlled. The control unit 10 includes a first main expansion valve 140, a second main expansion valve 150, a first injection expansion valve 172, a second injection expansion valve 182, and an intermediate expansion valve 190 according to operating conditions. Adjust the opening degree of ).

The discharge temperature sensor 11 is a sensor that measures the discharge temperature, which is the temperature of the refrigerant discharged to the discharge port 114 after being compressed by the compressor 110. The discharge temperature sensor 11 is located at various points to measure the temperature of the refrigerant discharged from the compressor 110, and is provided at point b in this embodiment.

The first intermediate temperature sensor 12 is a sensor that measures a first intermediate temperature, which is the temperature of the refrigerant flowing into the first main expansion valve 140 after condensation in the condenser 120. The first intermediate temperature sensor 12 is located at various points to measure the temperature of the refrigerant flowing into the first main expansion valve 140, and is provided at point c in this embodiment.

The second intermediate temperature sensor 13 is a sensor that measures a second intermediate temperature, which is the temperature of the refrigerant flowing into the intermediate expansion valve 190 after being separated from the first injection module 170. The second intermediate temperature sensor 13 is located at various points to measure the temperature of the refrigerant flowing into the intermediate expansion valve 190, and is provided at point f in this embodiment.

The third intermediate temperature sensor 14 is a sensor that measures a third intermediate temperature, which is the temperature of the refrigerant flowing into the second main expansion valve 150 after being separated from the second injection module 180. The third intermediate temperature sensor 14 is located at various points to measure the temperature of the refrigerant flowing into the second main expansion valve 150, and is provided at point n in this embodiment.

The control unit 10 adjusts the opening degree of the first main expansion valve 140 according to the discharge temperature measured by the discharge temperature sensor 11. The controller 10 adjusts the opening degree of the first main expansion valve 140 according to the discharge temperature to secure a suction superheat, which is the difference between the temperature of the refrigerant sucked into the compressor 110 and the temperature of the refrigerant evaporated from the evaporator 130. do.

The controller 10 adjusts the opening degree of the intermediate expansion valve 190 according to the first intermediate temperature measured by the first intermediate temperature sensor 12 and the second intermediate temperature measured by the second intermediate temperature sensor 13. The control unit 10 adjusts the opening degree of the intermediate expansion valve 190 so that the difference between the first intermediate temperature T1 and the second intermediate temperature T2 is equal to or greater than a predetermined target high pressure saturation temperature difference M1.

That is, T1-T2 ≥ M1 (M1 is a positive value)

T1 ≥ T2 + M1

Accordingly, the control unit 10 adjusts the opening degree of the intermediate expansion valve 190 so that the first intermediate temperature is greater than the second intermediate temperature.

The target high pressure saturation temperature difference M1 may be set according to the performance of the compressor 110 or may be set from a target high pressure saturated liquid temperature value obtained by multiplying the pressure of the refrigerant flowing into the first inlet port 111 by a set constant.

In this embodiment, the target high pressure saturation temperature difference M1 is 5 degrees Celsius.

The control unit 10 adjusts the opening degree of the second main expansion valve 150 according to the second intermediate temperature measured by the second intermediate temperature sensor 13 and the third intermediate temperature measured by the third intermediate temperature sensor 14. do. The control unit 10 adjusts the opening degree of the second main expansion valve 150 so that the difference between the second intermediate temperature T2 and the third intermediate temperature T3 is equal to or greater than a predetermined target low pressure saturation temperature difference M2.

That is, T2-T3 ≥ M2 (M1 is a positive value)

T2 ≥ T3 + M2

Accordingly, the control unit 10 adjusts the opening degree of the second main expansion valve 150 so that the second intermediate temperature is greater than the third intermediate temperature.

The target low pressure saturation temperature difference M2 may be set according to the performance of the compressor 110 or may be set from a temperature value of the target low pressure saturated liquid obtained by multiplying the pressure of the refrigerant flowing into the first inlet port 111 by a set constant.

In this embodiment, the target high pressure saturation temperature difference M2 is 5 degrees Celsius.

The control unit 10 adjusts the opening degree of the first injection expansion valve 172 according to the second intermediate temperature measured by the second intermediate temperature sensor 13. When the amount of change in the second intermediate temperature T2 during the reference time is greater than or equal to the preset target high pressure change amount D1, the control unit 10 increases the opening degree of the first injection expansion valve, otherwise maintains the opening degree. The amount of change in the second intermediate temperature T2 during the reference time is measured by the second intermediate temperature T2' measured by the second intermediate temperature sensor 13 before the reference time and the second intermediate temperature sensor 13 after the reference time. It is calculated by the difference between one second intermediate temperature (T2").

The controller 10 controls the opening degree of the first injection expansion valve 172 as follows.

If T2'-T2'' ≥ D1, the opening of the first injection expansion valve 172 increases

If T2'-T2'' <D1, the opening of the first injection expansion valve 172 is also maintained.

Accordingly, the control unit 10 increases the opening degree of the first injection expansion valve 172 when the second intermediate temperature T1 falls by more than the high pressure change amount D1 during the reference time.

In this embodiment, the target high pressure change amount D1 is 1 degree Celsius.

The control unit 10 adjusts the opening degree of the second injection expansion valve 182 according to the third intermediate temperature measured by the third intermediate temperature sensor 14. The controller 10 increases the opening degree of the second injection expansion valve when the variation of the third intermediate temperature T3 during the reference time is greater than or equal to the preset target low pressure variation D2, otherwise maintains the opening degree. The amount of change in the third intermediate temperature T3 during the reference time is measured by the third intermediate temperature T3' measured by the third intermediate temperature sensor 14 before the reference time and the third intermediate temperature sensor 14 after the reference time. It is calculated by the difference between one third intermediate temperature (T3'').

The controller 10 controls the opening degree of the second injection expansion valve 182 as follows.

If T3'-T3'' ≥ D2, the opening of the second injection expansion valve 182 increases

If T3'-T3'' <D1, the opening of the second injection expansion valve (182) is also maintained.

Accordingly, the controller 10 increases the opening degree of the second injection expansion valve 182 when the third intermediate temperature T1 falls by more than the low pressure change amount D2 during the reference time.

In this embodiment, the target low pressure change amount D2 is 1 degree Celsius.

3 is a view showing a pressure-enthalpy diagram (hereinafter, referred to as a P-h diagram) when an air conditioner is operated according to an embodiment of the present invention.

The operation of the air conditioner according to an embodiment of the present invention will be described with reference to FIGS. 1 and 3 as follows.

The refrigerant compressed by the compressor 110 is discharged through the discharge port 114. The refrigerant discharged to the discharge port 114 flows to the condenser 120 through point b.

The refrigerant flowing to the condenser 120 is condensed by exchanging heat with air. When the air conditioner is a cooler, the refrigerant flowing to the condenser 120 exchanges heat with outdoor air, and when the air conditioner is a heater, the refrigerant flowing to the condenser 120 exchanges heat with indoor air.

The refrigerant condensed in the condenser 120 flows to the first main expansion valve 140 through point c and expands. The first main expansion valve 140 is controlled according to the discharge temperature measured by the discharge temperature sensor 11. The refrigerant expanded in the first main expansion valve 140 flows to the first injection module 170 through point e.

The refrigerant flowing to the first injection module 170 flows into the first injection gas-liquid separator 171. The refrigerant introduced into the first injection gas-liquid separator 171 is separated into a gas phase refrigerant and a liquid refrigerant.

The gaseous refrigerant separated by the first injection gas-liquid separator 171 flows to the first injection expansion valve 172 and expands. The opening degree of the first injection expansion valve 172 is adjusted according to the second intermediate temperature T2 measured by the second intermediate temperature sensor 13. The refrigerant expanded by the first injection expansion valve 172 is injected into the high pressure side of the compressor 110 through the third inlet port 113 of the compressor 110 via point k.

The liquid refrigerant separated by the first injection gas-liquid separator 171 flows to the intermediate expansion valve 190 through point f and expands. The intermediate expansion valve 190 is controlled according to the first intermediate temperature T1 measured by the first intermediate temperature sensor 12 and the second intermediate temperature T2 measured by the second intermediate temperature sensor 13.

The refrigerant expanded in the intermediate expansion valve 190 flows to the second injection module 180 through the l point.

The refrigerant flowing to the second injection module 180 flows into the second injection gas-liquid separator 181. The refrigerant introduced into the second injection gas-liquid separator 181 is separated into a gas phase refrigerant and a liquid refrigerant.

The gaseous refrigerant separated by the second injection gas-liquid separator 181 flows to the second injection expansion valve 182 and expands. The opening degree of the second injection expansion valve 182 is adjusted according to the third intermediate temperature T3 measured by the third intermediate temperature sensor 14. The refrigerant expanded by the second injection expansion valve 182 is injected into the low pressure side of the compressor 110 through the second inlet port 112 of the compressor 110 through the point m.

The liquid refrigerant separated by the second injection gas-liquid separator 181 flows to the second main expansion valve 150 through n points and expands. The second main expansion valve 150 is controlled according to the second intermediate temperature T2 measured by the second intermediate temperature sensor 13 and the third intermediate temperature T3 measured by the third intermediate temperature sensor 14. .

The refrigerant expanded in the second main expansion valve 150 flows to the evaporator 130 through the point h.

The refrigerant flowing to the evaporator 130 is evaporated by heat exchange with air. When the air conditioner is a cooler, the refrigerant flowing to the evaporator 130 exchanges heat with indoor air, and when the air conditioner is a heater, the refrigerant flowing to the evaporator 130 exchanges heat with outdoor air.

The refrigerant evaporated in the evaporator 130 flows through the point a to the first inlet port 111 of the compressor 110. The refrigerant flowing through the first inlet port 111 is compressed by the compressor 110 and merges with the refrigerant injected into the second inlet port 112 and the third inlet port 113. The refrigerant compressed by the compressor 110 is discharged to the discharge port 114.

3, a discharge port 114 of a compressor 110, a condenser 120, a first main expansion valve 140, a first injection gas-liquid separator 171, a first injection expansion valve 172, and a compressor. The third inlet port 113 of (110) forms one cycle and forms one injection step.

In addition, the first injection gas-liquid separator 171, the intermediate expansion valve 190, the second injection gas-liquid separator 181, the second injection expansion valve 182, and the second inlet port 112 of the compressor 110 are one It forms another injection step by forming a cycle of.

In the above, preferred embodiments of the present invention have been illustrated and described, but the present invention is not limited to the specific embodiments described above, and in the technical field to which the present invention pertains without departing from the gist of the present invention claimed in the claims. Various modifications may be possible by those of ordinary skill in the art, and these modifications should not be individually understood from the technical spirit or prospect of the present invention.

110: compressor 120: condenser
130: evaporator 140: first main expansion valve
150: second main expansion valve 170: first injection module
171: first injection gas-liquid separator 172: first injection expansion valve
180: second injection module 181: second injection gas-liquid separator
182: second injection expansion valve 190: intermediate expansion valve

Claims (9)

A compressor that compresses a refrigerant;
A condenser for condensing the refrigerant compressed by the compressor;
A first main expansion valve for expanding the refrigerant condensed in the condenser;
A first injection module including a first injection gas-liquid separator for separating the refrigerant expanded from the first main expansion valve into a gaseous refrigerant and a liquid refrigerant, and a first injection expansion valve for expanding the separated gaseous refrigerant and injecting it into the compressor. ;
An intermediate expansion valve for expanding the liquid refrigerant separated from the first injection module;
A second injection module including a second injection gas-liquid separator for separating the refrigerant expanded from the intermediate expansion valve into a gaseous refrigerant and a liquid refrigerant, and a second injection expansion valve for expanding the separated gaseous refrigerant and injecting the separated gaseous refrigerant into the compressor;
A second main expansion valve for expanding the liquid refrigerant separated from the second injection module; And
An air conditioner comprising an evaporator for evaporating the refrigerant expanded in the second main expansion valve. The method of claim 1,
The first main expansion valve is an air conditioner controlled according to the temperature of the refrigerant discharged from the compressor. The method of claim 1,
The intermediate expansion valve is an air conditioner controlled according to a difference between the temperature of the refrigerant condensed in the condenser and introduced into the first main expansion valve and the temperature of the refrigerant separated from the first injection module and introduced into the intermediate expansion valve. . The method of claim 3,
The intermediate expansion valve is an air conditioner controlled so that the temperature of the refrigerant condensed in the condenser and introduced into the first main expansion valve is separated from the first injection module and controlled to be greater than the temperature of the refrigerant introduced into the intermediate expansion valve. The method of claim 1,
The second main expansion valve according to the difference between the temperature of the refrigerant separated from the first injection module and introduced into the intermediate expansion valve and the temperature of the refrigerant separated from the second injection module and introduced into the second main expansion valve. Air conditioner controlled. The method of claim 5,
The second main expansion valve is separated from the first injection module and controlled so that the temperature of the refrigerant introduced into the intermediate expansion valve is greater than the temperature of the refrigerant separated from the second injection module and introduced into the second main expansion valve. Air conditioner. delete The method of claim 1,
The first injection expansion valve is separated from the first injection gas-liquid separator and controlled according to the temperature of the refrigerant introduced into the intermediate expansion valve. The method of claim 1,
The second injection expansion valve is separated from the second injection gas-liquid separator and controlled according to the temperature of the refrigerant introduced into the second main expansion valve.

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