KR102125094B1 - Supercooling heat exchanger and air conditioning system including the same - Google Patents

Abstract

Supercooling heat exchanger according to an embodiment of the present invention, the outer pipe; A partition wall disposed inside the outer pipe and partitioning the outer pipe into first and second spaces; And at least one inner pipe disposed inside the outer pipe and penetrating the partition wall.
The outer piping includes: a first inlet communicating with an end of the first space side among both ends of the inner piping; A first outlet communicating with an end of the second space side of both ends of the inner pipe; A second entrance communicating with the first space; A second exit communicating with the first space and spaced apart from the second entrance; A third entrance communicating with the second space; And a third outlet communicating with the second space and spaced apart from the third entrance.

Description

Supercooling heat exchanger and air conditioning system including the same

The present invention relates to a supercooling heat exchanger and an air conditioning system comprising the same.

In general, heat naturally moves from the high temperature side to the low temperature side, but in order to transfer heat from the low temperature side to the high temperature side, some action must be applied from the outside. This is the principle of the heat pump. The heat pump air conditioner performs refrigeration or heating operation by reversibly using a transport mechanism for heat circulated in a refrigeration cycle consisting of compression-condensation-expansion-evaporation of the refrigerant, and is usually equipped with a compressor for compressing the refrigerant Doing.

Recently, in order to improve the cooling or heating capability of such a heat pump air conditioner, a vapor injection supercooler that injects a gaseous refrigerant into a compressor (specifically, a compression chamber) has been introduced.

In more detail, a branch pipe branched from a connection pipe connecting an indoor heat exchanger and an outdoor heat exchanger is connected to an injection port provided in a compressor, and a supercooling expansion valve for expanding a refrigerant is installed in the branch pipe. In this case, the supercooling heat exchanger performs heat exchange between the refrigerant passing through the connecting pipe and the refrigerant passing through the branch pipe. That is, the refrigerant expanded under reduced pressure in the supercooling expansion valve exchanges heat in the supercooling heat exchanger, and the superheated gaseous refrigerant is injected into the injection port of the compressor.

KR10-2010-0063173A (released on June 11, 2010)

The problem to be solved by the present invention is to provide a supercooling heat exchanger capable of two-stage cooling of the refrigerant passing through the inner pipe by the refrigerant introduced through different paths.

Another problem to be solved by the present invention is to provide a compact air conditioning system.

Another problem to be solved by the present invention is to provide an air conditioning system with improved air conditioning performance.

Supercooling heat exchanger according to an embodiment of the present invention, the outer pipe; A partition wall disposed inside the outer pipe and partitioning the inner portion of the outer pipe into a first space and a second space; And at least one inner pipe disposed inside the outer pipe and penetrating the partition wall. The outer piping includes: a first inlet communicating with an end of the first space side among both ends of the inner piping; A first outlet communicating with an end of the second space among both ends of the inner pipe; A second entrance communicating with the first space; A second outlet communicating with the first space and spaced apart from the second entrance; A third entrance communicating with the second space; And a third outlet communicating with the second space and spaced apart from the third entrance.

The length of the first space may be longer than the length of the second space.

The second entrance may be adjacent to the first entrance of the first entrance and the partition, and the second exit may be adjacent to the partition of the first entrance and the partition.

The third entrance may be adjacent to the first exit of the partition and the first exit, and the third exit may be adjacent to the partition of the partition and the first exit.

With respect to the longitudinal direction of the outer pipe, a distance between the second inlet and the second outlet may be greater than the distance between the third inlet and the third outlet.

Air conditioning system according to an embodiment of the present invention, the outer piping; At least one inner pipe disposed inside the outer pipe; A partition wall disposed in the outer pipe and penetrated by the inner pipe; A steam injection channel formed between an inner surface of the outer pipe and an outer surface of the inner pipe and located on one side of the partition wall; A bypass channel formed between an inner surface of the outer pipe and an outer surface of the inner pipe and located on the other side of the partition wall; A first connecting pipe communicating the inner pipe with the condenser; A steam injection inlet pipe branched from the first connection pipe and communicating with the steam injection flow path; A steam injection expansion valve installed in the steam injection inlet pipe; A steam injection outlet pipe communicating the steam injection passage with the suction portion of the compressor; A second connecting pipe communicating the inner pipe with the evaporator; A gas-liquid separating member separating a gas phase refrigerant and a liquid refrigerant in the evaporator; A bypass inlet pipe communicating the gas-liquid separation member and the bypass channel; A bypass outlet pipe communicating the bypass channel with the suction part of the compressor; And a bypass opening/closing valve installed in the bypass inlet pipe or the bypass outlet pipe.

The bypass outlet pipe may be connected between the suction part of the compressor and the accumulator with respect to the flow direction of the refrigerant.

With respect to the flow direction of the refrigerant, the length of the steam injection passage may be longer than the length of the bypass passage.

The gas-liquid separating member, a connection tube formed elongated in one direction and connected to the bypass inlet pipe; And a separation tube connected to the connection tube and constituting the return band of the evaporator.

The separation tube includes a connection portion to which the connection tube is connected and elongated in the one direction; And a return portion branched from the connection portion.

The connecting tube includes a large diameter portion connected to the bypass inlet pipe; And a small diameter part inserted into the connection part and having an outer diameter smaller than the inner diameter of the connection part.

The suction portion of the compressor, the low pressure suction portion to which the steam injection outlet pipe is connected; And a medium pressure suction part spaced apart from the low pressure suction part and connected to the bypass outlet pipe.

When the frequency of the compressor is greater than the set frequency, a controller that opens the bypass valve may be further included.

An evaporation temperature sensor measuring the evaporation temperature of the evaporator; And a controller that opens the bypass valve when the frequency of the compressor is greater than a set frequency and the temperature measured by the evaporation temperature sensor is equal to or less than a preset set temperature.

According to a preferred embodiment of the present invention, the refrigerant passing through the inner pipe is primarily cooled by the refrigerant passing through the steam injection passage and secondly cooled by the refrigerant passing through the bypass passage. Therefore, there is an advantage that the supercooling degree of the refrigerant can be effectively secured by the supercooling heat exchanger.

In addition, since the space in the outer pipe of the supercooling heat exchanger is partitioned by a partition wall, it is possible to prevent the refrigerant in the steam injection passage from being mixed with the refrigerant in the bypass passage.

In addition, since the length of the steam injection flow path is formed longer than the length of the bypass flow path with respect to the flow direction of the refrigerant, the refrigerant in the inner pipe can be sufficiently cooled even in the cooling operation in which the refrigerant does not flow in the bypass flow path.

In addition, the vapor phase refrigerant of the evaporator is separated by the gas-liquid separation member and flows into the bypass flow path, so that the pressure loss at the evaporator and the rear end of the evaporator can be minimized.

In addition, the refrigerant overheated in the steam injection channel may be injected into the medium pressure suction part of the compressor. Accordingly, it is possible to overcome the limitation of the refrigerant suction amount limited by the density of the refrigerant sucked into the low-pressure suction unit and the volume of the compression chamber, and to prevent the compressor discharge temperature from excessively rising when the compressor frequency increases. .

In addition, when the frequency of the compressor is greater than the set frequency, the bypass valve is opened, so that the refrigerant flowing into the gas-liquid separation member forms reflux so that the gaseous refrigerant and the liquid refrigerant can be easily separated from the gas-liquid separation member, and separated gaseous refrigerant. Can flow into the bypass channel.

In addition, the supercooling heat exchanger includes both the steam injection flow path and the bypass flow path, so that the pressure of the evaporator and the rear end of the evaporator is minimized by keeping the frequency of the compressor high, and the discharge temperature of the compressor is too high while maintaining the high frequency of the compressor Can be prevented.

In addition, since the supercooled heat exchanger includes both the steam injection flow path and the bypass flow path, the air conditioning system can be compact compared to the case where the supercooled heat exchanger including each flow path is separately provided.

1 is a block diagram of an air conditioning system according to an embodiment of the present invention.
2 is a view showing the flow of refrigerant during the heating operation of the air conditioning system according to an embodiment of the present invention.
3 is a view showing the flow of refrigerant during the cooling operation of the air conditioning system according to an embodiment of the present invention.
4 is a view showing the appearance of a supercooling heat exchanger according to an embodiment of the present invention.
5 is a view showing the interior of the supercooling heat exchanger according to an embodiment of the present invention.
6 is a view showing the appearance of the gas-liquid separation member according to an embodiment of the present invention.
7 is a view showing the interior of the gas-liquid separation member according to an embodiment of the present invention.
8 is a control block diagram of an air conditioning system according to an embodiment of the present invention.
9 is a flowchart illustrating an example of a control sequence of a bypass expansion valve according to an embodiment of the present invention.
10 is a flowchart illustrating another example of a control sequence of the bypass expansion valve according to an embodiment of the present invention.
11 is a block diagram of an air conditioning system according to another embodiment of the present invention.

Hereinafter, a specific embodiment of the present invention will be described in detail with the accompanying drawings.

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

The air conditioning system according to an embodiment of the present invention includes a compressor 10, four sides 14, an indoor heat exchanger 15, an outdoor heat exchanger 18, an indoor expansion valve 16, An outdoor expansion valve 17 and a supercooling heat exchanger 40 may be included.

The compressor 10 may be composed of an inverter compressor with adjustable frequency. In the compressor, a discharge unit 11 through which compressed refrigerant is discharged, and a suction unit 12 and 13 through which refrigerant is sucked into the compressor 10 may be formed.

The suction units 12 and 13 may include a low pressure suction unit 12 in communication with a low pressure compression chamber and a medium pressure suction unit 13 in communication with a medium pressure compression chamber. The low pressure suction unit 12 may be connected to the suction pipe 26, and the medium pressure suction unit 13 may be connected to the steam injection outlet pipe 32. The medium pressure suction part 13 may be referred to as an injection port.

Therefore, the compressor 10 compresses the low-temperature and low-pressure gaseous refrigerant sucked into the low-pressure suction unit 12 to discharge the high-temperature and high-pressure gaseous refrigerant through the discharge unit 11, and in the compression process, the low-pressure suction unit 12 In order to overcome the limitation of the refrigerant intake amount limited by the density of the refrigerant to be sucked and the volume of the compression chamber, the vapor injection outlet pipe 32 may inject gaseous refrigerant into the medium pressure suction part 13.

A discharge pipe 21 may be connected to the discharge portion 11 of the compressor 10, and a suction pipe 26 may be connected to the low pressure suction portion 12. The discharge pipe 21 can guide the refrigerant discharged from the discharge portion 11 of the compressor 10 to the four sides 14, and the suction pipe 26 compresses the refrigerant passing through the four sides 14 It can be guided to the low pressure suction part 12 of 10).

The discharge pipe 21 may be provided with a discharge temperature sensor 71 for detecting the discharge temperature of the compressor 10.

An accumulator 27 may be installed in the suction pipe 26 to prevent the liquid refrigerant from being sucked into the compressor 10 and causing pressure loss of the compressor 10. Among the refrigerants flowing into the accumulator 27, the liquid refrigerant sinks downward from the inside of the accumulator 27, and only the gaseous refrigerant located at the upper side can be sucked into the low pressure suction unit 12 of the compressor 10.

The four sides 14 may communicate one of the discharge pipe 21 and the suction pipe 26 with the indoor heat exchanger 15 and the other with the outdoor heat exchanger 18. That is, the four sides 14 may be switched to change the flow of the refrigerant according to the mode of cooling operation and heating operation according to the user's selection.

The indoor heat exchanger (15) is installed on the indoor side and serves as an evaporator for evaporating the low-temperature, low-pressure liquid-state refrigerant into a gaseous state in cooling operation, and a condenser for condensing the high-temperature, high-pressure gaseous refrigerant into normal temperature and high pressure liquid state in heating operation. By acting as, it can exchange heat with the surrounding air in response to a change in the enthalpy of the refrigerant.

One side of the indoor heat exchanger 15 may be connected to the four sides 14 by the first four sides piping 22, the other side may be connected to the supercooling heat exchanger 40 by the first connecting pipe 23. . The first oblique piping 22 may be selectively communicated with the discharge piping 21 or the suction piping 26 by the four sides.

The outdoor heat exchanger (18) is installed on the outdoor side and serves as an evaporator for evaporating the low-temperature, low-pressure liquid-state refrigerant into a gaseous state in the heating operation, and a condenser for condensing the high-temperature, high-pressure gaseous refrigerant into the normal temperature and high-pressure liquid state in the cooling operation. By acting as, it can exchange heat with the surrounding air in response to a change in the enthalpy of the refrigerant.

One side of the outdoor heat exchanger 18 may be connected to the four sides 14 by the second quadrangular piping 25, and the other side may be connected to the supercooling heat exchanger 40 by the second connecting pipe 24. . The second oblique piping 25 may be selectively communicated with the discharge piping 21 or the suction piping 26 by the four sides.

At least one gas-liquid separation member 60 may be provided in any one of the indoor heat exchanger 15 and the outdoor heat exchanger 18. The gas-liquid separation member 60 is preferably provided with a plurality.

Hereinafter, the case where the gas-liquid separation member 60 is provided in the outdoor heat exchanger 18 will be described as an example.

The outdoor heat exchanger 18 may be a fin tube heat exchanger including a plurality of fins, a plurality of hairpin tubes penetrating the fins, and a plurality of return bands communicating one hairpin tube with another hairpin tube.

In this case, the gas-liquid separation member 60 serves as the return band, and can separate the two-phase refrigerant passing through the outdoor heat exchanger 18 into a gaseous refrigerant and a liquid refrigerant during heating operation. The gaseous refrigerant separated from the gas-liquid separation member 60 may flow into the bypass inlet pipe 34, and the liquid refrigerant may evaporate from the outdoor heat exchanger 18 and flow into the suction pipe 26.

That is, the liquid refrigerant among the refrigerants of the outdoor heat exchanger (18) acting as an evaporator during the heating operation may be separated by the gas-liquid separation member (80) and flow out into the bypass inlet pipe (34). Accordingly, pressure loss in the outdoor heat exchanger 18, the second quadrilateral connecting pipe 25, and the suction pipe 26 is prevented, and the performance of the air conditioning system can be improved.

The detailed configuration of the gas-liquid separation member 60 will be described later in detail.

At least one of the outdoor heat exchanger 18, the second connection pipe 24 and the second quadrangular pipe 25 may be provided with a temperature sensor for sensing the temperature of the refrigerant. For example, an evaporation temperature sensor 72 that measures the evaporation temperature of the outdoor heat exchanger 18 during heating operation may be installed adjacent to the outdoor heat exchanger 18 in the second connection pipe 24.

The indoor expansion valve 16 is installed in the first connection pipe 23 and may be positioned between the indoor heat exchanger 15 and the supercooled heat exchanger 40. The indoor expansion valve 16 may be configured with an electronic expansion valve (EEV).

The indoor expansion valve (16) is installed on the indoor side and expands the refrigerant in the room temperature and high pressure liquid state, which is condensed in the outdoor heat exchanger (18) during cooling operation, into a two-phase refrigerant that is a low-temperature and low-pressure mixture of liquid and gas components. can do. The indoor expansion valve 16 is controlled to the opening degree at which the refrigerant expands during cooling operation, and is opened to the maximum during heating operation to prevent pressure loss.

The outdoor expansion valve 17 is installed in the second connection pipe 24 and may be positioned between the outdoor heat exchanger 18 and the supercooled heat exchanger 40. The outdoor expansion valve 17 may be configured as an electronic expansion valve (EEV).

The outdoor expansion valve (17) is installed on the outdoor side and expands the refrigerant in the room temperature and high pressure liquid state condensed in the indoor heat exchanger (15) during heating operation to low temperature and low pressure to expand it into a two-phase refrigerant mixed with liquid components and gas components to reduce pressure. can do. The outdoor expansion valve (17) is controlled by the opening degree of refrigerant expansion during heating operation, and is opened to the maximum during cooling operation to prevent pressure loss.

The supercooled heat exchanger 40 may be a multi-tube heat exchanger. The supercooling heat exchanger 40 includes an outer pipe 41 that forms an exterior, at least one inner pipe 42 disposed inside the outer pipe 41, and an inner portion disposed inside the outer pipe 41. A partition wall 43 penetrated by the pipe 42 may be included.

The supercooling heat exchanger 40 may supercool the refrigerant flowing through the inner pipe 42 by exchanging heat with a low-temperature refrigerant flowing between the outer pipe 41 and the inner pipe 42.

In more detail, the supercooling heat exchanger 40 includes a first inlet 51, a first outlet 52, a second inlet 53, a second outlet 54, a third inlet 55, and a third outlet ( 56) may be formed.

A first connection pipe 23 may be connected to the first entrance 51. The first inlet 51 may communicate with one side of the inner pipe 42. The second connection pipe 24 may be connected to the first outlet 52. The first outlet 52 may communicate with the other side of the inner pipe 42.

That is, the refrigerant flowing into the first inlet 51 from the first connecting pipe 23 based on the heating operation passes through the inner pipe 42 to the second connecting pipe 24 through the first outlet 52. Can be flowed.

A steam injection inlet pipe 31 branched from the first connection pipe 23 may be connected to the second inlet 53. The second inlet 53 may communicate with one side of the steam injection passage 44 inside the outer pipe 41. A steam injection outlet pipe 32 connected to the medium pressure suction part 13 of the compressor 10 may be connected to the second outlet 54. The second outlet 54 may communicate with the other side of the steam injection flow passage 44. In this case, the steam injection flow path 44 is located on one side of the partition wall 43 and may mean a space formed between the outer pipe 41 and the inner pipe 42.

In addition, a steam injection expansion valve 33 that expands and cools the refrigerant may be installed in the steam injection inlet pipe 31. The steam injection expansion valve 33 may be configured as an electronic expansion valve (EEV).

That is, some of the refrigerant in the first connection pipe 23 is introduced into the steam injection inlet pipe 31 based on the heating operation, and may be expanded and cooled while passing through the steam injection expansion valve 33. Thereafter, the refrigerant flows into the second inlet 53 and cools the refrigerant passing through the steam injection passage 44 and passing through the inner pipe 42. Subsequently, the refrigerant in the steam injection flow passage 44 may be discharged to the second outlet 54 and guided by the steam injection outlet pipe 32 to be injected into the medium pressure suction part 13 of the compressor 10. .

A bypass inlet pipe 34 connected to the gas-liquid separation member 60 of the outdoor heat exchanger 18 may be connected to the third inlet 55. The third inlet 55 may communicate with one side of the bypass flow path 45 inside the outer pipe 41. A bypass outlet pipe 35 connected to the suction pipe 26 may be connected to the third outlet 56. The third outlet 56 may communicate with the other side of the bypass flow passage 45. In this case, the bypass flow passage 45 is located on the other side of the partition wall 43 and may mean a space formed between the outer pipe 41 and the inner pipe 42.

In addition, a bypass valve 36 that regulates the flow of the refrigerant may be installed in the bypass inlet pipe 34 or the bypass outlet pipe 35. The bypass valve 36 may control the flow rate of the refrigerant or be opened or closed. Hereinafter, a case where the bypass valve 36 is installed in the bypass outlet pipe 35 will be described as an example, as illustrated in FIG. 1.

That is, based on the heating operation, gaseous refrigerant separated from the gas-liquid separation member 60 of the outdoor heat exchanger 18 flows into the third inlet 55 through the bypass inlet pipe 34, and the bypass flow passage 45 ) To cool the refrigerant passing through the inner pipe 42. Subsequently, the refrigerant in the bypass flow passage 45 may be discharged to the third outlet 56, guided by the bypass outlet pipe 35, and flow to the suction pipe 26, and the compressor 10 It can be sucked into the low pressure suction unit 12.

In this case, it is preferable that the connecting portion of the bypass outlet pipe 35 and the suction pipe 26 is a portion adjacent to the low pressure suction portion 12 of the compressor 10. That is, the bypass outlet pipe 35 may be connected between the accumulator 27 and the compressor 10 among the suction pipes 35. As a result, there is an advantage of minimizing the pressure loss of the refrigerant flow flowing through the four sides 14 to the suction pipe 26.

2 is a view showing the flow of refrigerant during the heating operation of the air conditioning system according to an embodiment of the present invention.

Hereinafter, the flow of the refrigerant circulating in the air conditioning system during the heating operation will be described with reference to FIG. 2.

During the heating operation, the four sides 14 may communicate the discharge part 11 of the compressor 10 with the indoor heat exchanger 15, and the low pressure suction part 12 of the compressor 10 may be used as an outdoor heat exchanger 18. ). Therefore, during the heating operation, the indoor heat exchanger 15 may be referred to as a condenser, and the outdoor heat exchanger 18 may be referred to as an evaporator.

The refrigerant compressed by the compressor 10 and discharged to the discharge portion may sequentially pass through the discharge pipe 21, the four sides 14, and the first four sides connecting pipe 22 to flow to the indoor heat exchanger 15. . The refrigerant can be condensed while heating the ambient air in the indoor heat exchanger (15). Thus, indoor heating can be achieved.

The refrigerant condensed in the indoor heat exchanger 15 may be directed to the supercooling heat exchanger 40 through the first connection pipe 23. In this case, since the indoor expansion valve 16 is in a fully open state, the refrigerant can pass through the indoor expansion valve 16 without pressure loss.

Some of the refrigerant in the first connection pipe 23 may be introduced into the first inlet 51 of the supercooling heat exchanger 40. The other part of the refrigerant in the first connection pipe 23 flows into the steam injection inlet pipe 31 and expands and cools in the steam injection expansion valve 33 to the second inlet 53 of the supercooling heat exchanger 40 Can be introduced.

Hereinafter, for convenience of description, the refrigerant flow flowing into the first inlet 51 of the supercooling heat exchanger 40 is referred to as a main refrigerant flow, and refrigerant flowing into the second inlet 53 of the supercooling heat exchanger 40. The flow is called the steam injection refrigerant flow. In addition, the refrigerant flow flowing into the third inlet 55 of the supercooling heat exchanger 40 is referred to as a bypass refrigerant flow.

The main refrigerant flow flowing into the first inlet 51 is a vapor injection refrigerant flow passing through the steam injection flow path 44 in the process of passing through the inner pipe 42, and a bypass passing through the bypass flow path 45 It can be cooled by refrigerant flow.

In more detail, the main refrigerant flow may be primarily cooled by the vapor injection refrigerant flow in the process of passing the first inner piping portion 42A (see FIG. 5) located on one side of the partition wall 43, , In the process of passing through the second inner piping portion 42B (see FIG. 5) located on the other side of the partition wall 43, it may be secondarily cooled by the bypass refrigerant flow.

The main refrigerant flow may pass through the inner pipe 42 and be supercooled and then flow to the second connection pipe 24 connected to the first outlet 52.

Meanwhile, since the steam injection refrigerant flow flowing into the second inlet 53 is expanded and cooled while passing through the steam injection expansion valve 33, it may be lower than the main refrigerant flow. Therefore, the steam injection refrigerant flow is superheated in the process of passing through the steam injection flow path 44 and can cool the main refrigerant flow passing through the first inner piping portion 42A.

The direction of the steam injection refrigerant flow through the steam injection flow passage 44 may be parallel to the direction of the main refrigerant flow passing through the inner pipe 42.

The steam injection refrigerant flow passes through the steam injection flow passage 44 and can be flowed to the steam injection outlet pipe 32 connected to the second outlet 54 after being overheated, and the medium pressure suction part 13 of the compressor 10 Can be sprayed on. As a result, it is possible to overcome the limitation of the refrigerant suction amount limited by the density of the refrigerant sucked into the low pressure suction unit 12 and the volume of the compression chamber. Further, when the frequency of the compressor 10 rises, it is possible to prevent the discharge temperature of the compressor 10 from excessively rising.

Meanwhile, the main refrigerant flow flowing through the second connection pipe 24 may be expanded and cooled while passing through the outdoor expansion valve 17 and may be introduced into the outdoor heat exchanger 18. In this case, the refrigerant flowing into the outdoor heat exchanger 18 may be a two-phase refrigerant in which gaseous refrigerant and liquid refrigerant are mixed.

The refrigerant introduced into the outdoor heat exchanger 18 may be separated into a liquid refrigerant and a gaseous refrigerant by the gas-liquid separation member 60 in the process of passing through the outdoor heat exchanger 18. The gaseous refrigerant separated by the gas-liquid separation member 60 may be introduced into the third inlet 55 of the supercooling heat exchanger 40 through the bypass inlet pipe 34, and the liquid refrigerant may be an outdoor heat exchanger 18. Can continue to pass through and evaporate. As described above, the refrigerant flow flowing into the third inlet 55 of the supercooling heat exchanger 40 is referred to as a bypass refrigerant flow. In this case, the bypass valve 36 may be open.

By separating the gaseous refrigerant from the outdoor heat exchanger 18 serving as an evaporator and flowing only the liquid refrigerant, there is an advantage that pressure loss in the outdoor heat exchanger 18 can be minimized. In addition, pressure loss in the second quadrangular connecting pipe 25 and the suction pipe 26 located at the rear end of the outdoor heat exchanger 18 with respect to the flow direction of the refrigerant may also be minimized.

Since the bypass refrigerant flow introduced into the third inlet 55 is expanded and cooled while passing through the outdoor expansion valve 17, it may be colder than the main refrigerant flow. Therefore, the bypass refrigerant flow is superheated in the process of passing through the bypass flow passage 45, and the main refrigerant flow passing through the second inner piping portion 42B (see FIG. 5) can be cooled.

The direction of the bypass refrigerant flow through the bypass flow passage 45 may be opposite to the direction of the main refrigerant flow through the inner pipe 42.

The bypass refrigerant flow may pass through the bypass flow passage 45 and after being overheated, may flow to the bypass outlet pipe 35 connected to the third outlet 56, and the low pressure suction part 12 of the compressor 10 Can be inhaled with.

On the other hand, the refrigerant evaporated in the outdoor heat exchanger (18) may flow through the second quadrilateral connecting pipe (25) and the quadrilateral (14) sequentially to the suction pipe (26), and the liquid in the accumulator (27). After being separated into a refrigerant and a gaseous refrigerant, the gaseous refrigerant may be sucked into the low pressure suction unit 12 of the compressor 10.

Thereafter, the compressor 10 may compress the refrigerant sucked into the low pressure suction part 12 and the medium pressure suction part 13 and discharge the refrigerant to the discharge part 11, and the discharged refrigerant repeats the above-described process to perform air conditioning. The system can be cycled.

3 is a view showing the flow of refrigerant during the cooling operation of the air conditioning system according to an embodiment of the present invention.

Hereinafter, the flow of the refrigerant circulating in the air conditioning system during cooling operation will be described with reference to FIG. 3.

During the cooling operation, the four sides 14 can communicate the discharge portion 11 of the compressor 10 with the outdoor heat exchanger 18, and the low pressure suction portion 12 of the compressor 10 is an indoor heat exchanger 15 ). Therefore, the indoor heat exchanger 15 may be referred to as an evaporator during cooling operation, and the outdoor heat exchanger 18 may be referred to as a condenser.

The refrigerant compressed by the compressor 10 and discharged to the discharge part may sequentially pass through the discharge pipe 21, the four sides 14, and the second four sides connecting pipe 25 to flow to the outdoor heat exchanger 18. . The refrigerant may be condensed while heating the ambient air in the outdoor heat exchanger (18).

In the cooling operation, the bypass valve 36 may be closed. In addition, since the refrigerant introduced into the outdoor heat exchanger 18 is a gaseous refrigerant, gas-liquid separation may not occur. Therefore, the refrigerant condensed in the outdoor heat exchanger 18 may not flow to the supercooling heat exchanger 40 through the bypass inlet pipe 34.

The refrigerant condensed in the outdoor heat exchanger 18 may be directed to the supercooling heat exchanger 40 through the second connection pipe 24. In this case, since the outdoor expansion valve 17 is fully open, the refrigerant can pass through the outdoor expansion valve 17 without loss of pressure.

The refrigerant in the second connection pipe 24 may be introduced into the first outlet 52 of the supercooling heat exchanger 40. The refrigerant flowing into the first outlet 52 may be cooled by the refrigerant passing through the steam injection flow path 44 in the process of passing through the inner pipe 42.

The refrigerant cooled through the inner pipe 42 may flow to the first connection pipe 23 connected to the first inlet 51.

Some of the refrigerant in the first connection pipe 23 passes through the indoor expansion valve 16, expands and cools, and may flow to the indoor heat exchanger 15. The other part of the refrigerant in the first connection pipe 23 flows into the steam injection inlet pipe 31 and expands and cools in the steam injection expansion valve 33 to the second inlet 53 of the supercooling heat exchanger 40 Can be introduced.

The refrigerant flowing into the second inlet 53 is overheated in the process of passing through the steam injection flow path 44 and can cool the refrigerant passing through the inner pipe 42.

The direction of the refrigerant flow through the steam injection flow passage 44 may be opposite to the direction of the refrigerant flow through the inner pipe 42.

The refrigerant that has been superheated while passing through the steam injection flow passage 44 may be flowed into the steam injection outlet pipe 32 connected to the second outlet 54, and may be injected into the medium pressure suction part 13 of the compressor 10. . As a result, there is an advantage of overcoming the limitation of the refrigerant suction amount limited by the density of the refrigerant sucked into the low-pressure suction unit 12 and the volume of the compression chamber.

On the other hand, the refrigerant flowing into the indoor heat exchanger 15 can be evaporated while cooling the air around the indoor heat exchanger, whereby indoor cooling can be achieved.

The refrigerant evaporated in the indoor heat exchanger (15) can be sequentially passed through the first four sides connecting pipe (22) and the four sides (14) to flow into the suction pipe (26), and the liquid refrigerant in the accumulator (27). After being separated into a gaseous refrigerant, the gaseous refrigerant may be sucked into the low pressure suction part 12 of the compressor 10.

Thereafter, the compressor 10 may compress the refrigerant sucked into the low pressure suction part 12 and the medium pressure suction part 13 and discharge the refrigerant to the discharge part 11, and the discharged refrigerant repeats the above-described process to perform air conditioning. The system can be cycled.

4 is a view showing the appearance of a supercooled heat exchanger according to an embodiment of the present invention, and FIG. 5 is a view showing the interior of a supercooled heat exchanger according to an embodiment of the present invention.

The supercooling heat exchanger 40 has an outer pipe 41 and a partition wall disposed inside the outer pipe 41 and partitioning the inner portion of the outer pipe 41 into a first space S1 and a second space S2 ( 43) and at least one inner pipe 42 disposed inside the outer pipe 41 and penetrating the partition wall 43.

The outer pipe 41 may form the appearance of the supercooling heat exchanger 40.

In one example, the outer pipe 41 may be formed by two members fastened. In this case, one side of either of the two members may be closed to constitute the partition wall 43. However, it is not limited thereto.

The inner space of the outer pipe 41 may be divided into a first space S1 and a second space S2 by the partition wall 43. The first space S1 may include the steam injection flow passage 44, and the second space S2 may include the bypass flow passage 45.

The length of the first space S1 may be longer than the length of the second space S2. That is, the length of the vapor injection passage 44 with respect to the flow direction of the refrigerant may be longer than the length of the bypass passage 45. Therefore, even in the cooling operation in which the refrigerant does not flow through the bypass flow passage 45, the main refrigerant flow through the inner pipe 42 may be sufficiently cooled by the refrigerant passing through the steam injection flow passage 44.

A first inlet 51, a first outlet 52, a second inlet 53, a second outlet 54, a third inlet 55 and a third outlet 56 are formed in the outer pipe 41. Can.

The first inlet 51 may be in communication with the end of the first space S1 side of both ends of the inner pipe 42, and the first outlet 52 is the second space of both ends of the inner pipe 42 It may be in communication with the end of the (S2) side.

The first inlet 51 may be provided with a first inlet connector 51A to which the first connecting pipe 23 is connected, and a first outlet in which the second connecting pipe 24 is connected to the first outlet 52. A connector 52A can be provided.

The second entrance 53 and the second exit 54 may communicate with the first space S1. In addition, the second entrance 53 and the second exit 54 may be spaced apart from each other.

The second inlet 53 may be provided with a second inlet connector 53A to which the steam injection inlet pipe 31 is connected, and the second outlet 54 may be provided with a second outlet to which the steam injection outlet pipe 32 is connected. A connector 54A can be provided.

The second entrance 53 is adjacent to the first entrance 51 of the first entrance 51 and the partition wall 43, and the second exit 54 is the partition wall of the first entrance 51 and the partition wall 43 ( 43).

The third entrance 55 and the third exit 56 may communicate with the second space S2. Also, the third inlet 55 and the third outlet 56 may be spaced apart from each other.

A third inlet 55 may be provided with a third inlet connector 55A to which the bypass inlet pipe 34 is connected, and a third outlet 56 to which a bypass outlet pipe 35 may be connected. A connector 56A can be provided.

The third entrance 55 is adjacent to the first exit 52 of the partition 43 and the first exit 52, and the third exit 56 is the partition of the partition 43 and the first exit 52 ( 43).

With respect to the longitudinal direction of the outer pipe 41, the distance between the second inlet 53 and the second outlet 54 may be greater than the distance between the third inlet 55 and the third outlet 56. That is, the path length of the steam injection flow path 44 may be longer than the path length of the bypass flow path 45. Accordingly, the refrigerant in the inner pipe 42 can be sufficiently cooled even in the cooling operation in which the refrigerant does not flow into the bypass flow passage 55.

Meanwhile, the inner pipe 42 may be disposed inside the outer pipe 41. At least one inner pipe 42 may be provided, and it is preferable that it is a plurality.

The outer circumference of the inner pipe 42 may be spaced apart from the inner circumference of the outer pipe 41. The inner pipe 42 may penetrate the partition wall 43 and may be disposed over the first space S1 and the second space S2. That is, the inner piping 42 includes a first inner piping portion 42A located in a first space S1 located on one side of the partition wall 43 and a second space S2 located on the other side of the partition wall 43. It may include a second inner piping portion (42B) located in.

In the first space S1, a steam injection flow path 44 may be formed between the inner surface of the outer pipe 41 and the outer surface of the inner pipe 42. In more detail, a steam jet flow path 44 may be formed between the inner surface of the outer pipe 41 and the outer surface of the first inner pipe portion 42A.

The bypass passage 45 may be formed between the inner surface of the outer pipe 41 and the outer surface of the inner pipe 42 in the second space S2. In more detail, a bypass flow passage 45 may be formed between the inner surface of the outer pipe 41 and the outer surface of the second inner pipe portion 42B.

The inner pipe 42 may include a material having high thermal conductivity. As a result, heat exchange between the refrigerant in the first inner piping portion 42A and the refrigerant in the vapor injection passage 44 can be smoothly performed, and heat exchange between the refrigerant in the second inner piping portion 42B and the refrigerant in the bypass flow passage 45 This can be done smoothly.

The partition wall 43 may divide the inside of the outer pipe 41 into a first space S1 and a second space S2. The partition wall 43 can prevent the refrigerant in the vapor injection passage 44 and the refrigerant in the bypass passage 45 from mixing with each other.

A through hole through which the inner pipe 42 passes may be formed in the partition wall 43. In order to prevent the refrigerant from flowing between the inner circumference of the through hole and the outer circumference of the inner pipe 42, a sealing (not shown) may be provided in the partition wall 43.

6 is a view showing the appearance of the gas-liquid separation member according to an embodiment of the present invention, Figure 7 is a view showing the interior of the gas-liquid separation member according to an embodiment of the present invention.

As described above, the gas-liquid separation member 60 serves as a return band of the evaporator (hereinafter, referred to as “18”) (see FIG. 2), and at the same time, cools the two-phase refrigerant in the evaporator 18 as a vapor phase And liquid refrigerant.

In more detail, the gas-liquid separation member 60 is a connection tube 61 connected to the bypass inlet pipe 34 and a separation tube 64 connected to the connection tube 61 and forming a return band of the evaporator 18 ).

The connection tube 61 may be formed long in one direction. The connecting tube 61 may include a large-diameter portion 62 and a small-diameter portion 63 having an inner diameter smaller than that of the large-diameter portion 62. The bypass inlet pipe 34 may be connected to one end of the large diameter portion 62, and the small diameter portion 63 may be extended to the other end.

The outer diameter of the small diameter portion 63 may be smaller than the inner diameter of the connection portion 65 of the separation tube 64. In more detail, the outer circumference of the small diameter portion 63 may be spaced apart from the inner circumference of the connection portion 65.

The separation tube 64 may serve as a return band of the evaporator 18. The separation tube 64 may have an approximately “h” shape.

In more detail, the separation tube 64 includes a connection part 65 to which the connection tube 61 is connected and formed elongated in a direction parallel to the connection tube 61, and a return part 66 branched from the connection part 65 can do.

An insertion portion 67 into which the connection tube 61 is interpolated may be formed in the connection portion 65. The connection tube 61 may be fitted to the insertion portion 67 and coupled to the separation tube 64. In this case, the large-diameter portion 62 of the connection tube 61 may be mounted to the insertion portion 67 and the small-diameter portion 63 may be located inside the connection portion 65.

The return portion 66 of the separation tube 64 includes a branch portion 66A branched from the connection portion 65, a curved pipe portion 66B extending from the branch portion 66B, and a curved pipe portion 66B extending from the branch portion 66B. It may include an extension (66C).

The branch portion 66A may be formed long in a direction perpendicular to the connection portion 65, and the extension portion 66B may be formed long in a direction parallel to the connection portion 65. The bent portion 66B may connect the branch portion 66A and the extension portion 66C.

Hereinafter, the operation of the gas-liquid separation member 60 will be described.

The flow of refrigerant flowing from the evaporator 18 to the connection portion 65 of the separation tube 64 may be an annular flow. In this case, due to the flow characteristics of the annular flow, the liquid refrigerant may flow adjacent to the inner wall of the connecting portion 65, and the gaseous refrigerant may flow away from the inner wall of the connecting portion 65. That is, the liquid refrigerant may flow relatively from the outside and the gaseous refrigerant may flow from the inside than the liquid refrigerant.

Accordingly, gaseous refrigerant among refrigerants in the connection portion 65 may be introduced into the small diameter portion 63, and liquid refrigerant is introduced between the outer circumference of the small diameter portion 63 and the inner circumference of the connection portion 65 to separate the tube 64. It can be flowed to the return unit (66).

The gaseous refrigerant introduced into the small-diameter portion 63 of the connection tube 61 may be guided to the supercooling heat exchanger 40 through the bypass inlet pipe 34. In addition, even though some liquid refrigerant flows into the small-diameter portion 63, it may expand in the process of flowing to the large-diameter portion 62 and phase change into a gas. Thus, the connecting tube 61 can collect the gaseous refrigerant as much as possible and guide it to the bypass inlet pipe 34.

In addition, the liquid refrigerant flowed to the return portion 66 of the separation tube 64 may be flowed back to the evaporator 18 to be evaporated. As a result, pressure loss in the pipe between the evaporator 18 and the evaporator 18 and the compressor 10 can be minimized.

8 is a control block diagram of an air conditioning system according to an embodiment of the present invention.

The air conditioning system according to an embodiment of the present invention may further include a controller 80.

The controller 80 can control the overall operation of the air conditioning system.

The controller 80 may receive detection values of a plurality of sensors included in the air conditioning system. For example, the controller 80 may receive detection values of the indoor temperature sensor 73, the outdoor temperature sensor 74, the discharge temperature sensor 71, and the evaporation temperature sensor 72.

The air conditioning system may further include an indoor temperature sensor 73 that senses the indoor temperature, and an outdoor temperature sensor 74 that senses the outdoor temperature.

In addition, the air conditioning system may further include an input unit 75. The user may input a command through the input unit 75, and the controller may receive the command and perform driving accordingly. For example, the user may determine cooling/heating operation through the input unit 75 or input a desired indoor temperature. The input unit 75 may be a switch or a button, and the configuration is not limited.

The controller 80 may turn the compressor 10 on or off, or control the frequency of the compressor 10. In addition, the controller 80 may receive the frequency of the compressor 10 in operation.

The controller 80 may adjust the opening degree of the steam injection expansion valve 33 to expand and cool the refrigerant passing through the steam injection expansion valve 33 and control the superheat degree of the supercooling heat exchanger 40.

The controller 80 may adjust the opening degree of the steam injection expansion valve 33 according to the load of the indoor heat exchanger 15. In one example, the controller 80 may calculate the load of the indoor heat exchanger 15 through the difference between the desired room temperature input through the input unit 75 and the room temperature detected by the room temperature sensor 73, thereby Accordingly, the opening degree of the steam injection expansion valve 33 can be adjusted.

The controller 80 may adjust the opening degree of the bypass valve 36 to adjust the flow rate of the refrigerant bypassed from the evaporator 18 to the bypass inlet pipe 34.

The controller 80 can switch and control the four sides 14. In the heating operation, the controller 80 is connected so that the discharge portion 11 of the compressor 10 communicates with the indoor heat exchanger 15 and the low pressure suction portion 12 of the compressor 10 communicates with the outdoor heat exchanger 18. The side 14 can be controlled. In the cooling operation, the controller 80 is connected so that the discharge portion 11 of the compressor 10 communicates with the outdoor heat exchanger 18 and the low pressure suction portion 12 of the compressor 10 communicates with the indoor heat exchanger 15. The side 14 can be controlled.

The controller 80 may control the opening degree of the outdoor expansion valve 17 and the indoor expansion valve 16, respectively. During the heating operation, the controller 80 may control the indoor expansion valve 16 to the maximum opening degree and the outdoor expansion valve 17 to the opening degree at which the refrigerant expands. In the cooling operation, the controller 80 may control the outdoor expansion valve 17 to the maximum opening degree and the indoor expansion valve 16 to the opening degree at which the refrigerant expands.

9 is a flowchart illustrating an example of a control sequence of a bypass expansion valve according to an embodiment of the present invention.

The controller 80 may open the bypass valve 36 when the frequency of the compressor 10 is greater than the set frequency during heating operation.

In more detail, the controller 80 may determine whether the frequency of the compressor 10 is greater than a preset frequency during heating operation (S1). In one example, the set frequency may be 75Hz.

In order to smoothly separate the gaseous refrigerant and the liquid refrigerant from the gas-liquid separation member 60, it is preferable that the refrigerant flow flowing into the connection portion 65 forms an annular flow as described above. In order for the refrigerant flow to form an annular flow, the vapor quality and mass velocity of the refrigerant in the evaporator 18 must satisfy conditions within a certain range, respectively. Vapor quality and mass velocity are well known terms, so detailed descriptions thereof are omitted.

The dryness range of the refrigerant flowing into the evaporator 18 (eg, 0.5 to 0.6) may be relatively constant. In this case, if the mass flow rate of the refrigerant is less than or equal to a certain value, a stratified wavy flow may be formed instead of an annular flow, and in this case, the gas-phase refrigerant and the liquid refrigerant are smooth in the gas-liquid separator 60. May not be separated.

Therefore, in order to smoothly separate the gaseous refrigerant and the liquid refrigerant from the gas-liquid separation member 60, the mass flow rate of the refrigerant must be maintained above the predetermined value, and for this, the frequency of the compressor 10 is maintained higher than the set frequency. desirable.

Therefore, the controller 80 may open the bypass valve 36 when the frequency of the compressor 10 is greater than a preset frequency during heating operation (S2). As a result, the gaseous refrigerant separated from the liquid refrigerant in the gas-liquid separation member 60 sequentially passes through the bypass inlet pipe 34, the bypass flow passage 45, and the bypass outlet pipe 35, thereby lowering the pressure of the compressor 10. It can be sucked into the suction unit 12. On the other hand, the controller 80 may close the bypass valve 36 when the frequency of the compressor 10 is less than or equal to a preset frequency during heating operation (S3).

10 is a flowchart illustrating another example of a control sequence of the bypass expansion valve according to an embodiment of the present invention.

The controller 80 may open the bypass valve 36 when the frequency of the compressor 10 is greater than the set frequency during the heating operation and the measured evaporation temperature is equal to or less than the set evaporation temperature (S1) (S4) (S2). On the other hand, the controller 80 may close the bypass valve 36 when the frequency of the compressor 10 is less than or equal to the set frequency during heating operation (S1) (S3). In addition, the controller 80 may close the bypass valve 36 when the measured evaporation temperature is greater than the set evaporation temperature even if the frequency of the compressor 10 is greater than the set frequency during heating operation (S1) (S4) (S3) ).

In this case, the measured evaporation temperature may be the temperature detected by the evaporation temperature sensor 72, and the set evaporation temperature may be a preset temperature.

When the outdoor temperature detected by the outdoor temperature sensor 74 during heating operation is low, the evaporation temperature detected by the evaporation temperature sensor 72 may be lowered to satisfy the evaporation load in the evaporator 18, and when the evaporation temperature decreases The suction pressure of the compressor 10 may drop. Therefore, in this case, it is preferable that the vapor phase refrigerant is separated from the gas-liquid separator to minimize pressure loss on the evaporator 18 and the rear end of the evaporator 18.

In addition, it is preferable that the frequency of the compressor 10 is greater than the set frequency to compensate for the decrease in the mass flow rate of the refrigerant according to the drop in the suction pressure of the compressor 10 to maintain an annular flow.

11 is a block diagram of an air conditioning system according to another embodiment of the present invention.

The air conditioning system according to the present embodiment is the same as the embodiment described in FIG. 1 except for the configuration of the bypass inlet pipes 34A and 34B, so the overlapping contents are omitted and the difference will be mainly described.

The bypass inlet pipes 34A and 34B connecting the gas-liquid separation member 60 and the third inlet 55 of the supercooled heat exchanger 40 have a first inlet located before the accumulator 27 with respect to the refrigerant flow direction. A piping portion 34A and a second inlet pipe portion 34B located after the accumulator 27 with respect to the refrigerant flow direction may be included.

The first inlet pipe portion 34A may connect the gas-liquid separation member 60 and the accumulator 27. The first inlet pipe portion 34A may guide the gaseous refrigerant separated from the gas-liquid separation member 60 to the accumulator 27.

The second inlet pipe portion 34B may connect the accumulator 27 and the third inlet 55. In more detail, the second inlet pipe portion 34B may be connected to the lower portion of the accumulator 27. The second inlet pipe portion 34B may guide the liquid refrigerant accumulated under the accumulator to the third inlet of the supercooling heat exchanger.

The liquid refrigerant flowing into the third inlet may be overheated while passing through the bypass flow passage 45, and cool the refrigerant passing through the inner pipe 42. The superheated refrigerant may be discharged to the third outlet 56 and passed through the bypass outlet pipe 35 to be sucked into the low pressure suction part 12 of the compressor 10.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and variations without departing from the essential characteristics of the present invention.

Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments.

The scope of protection of the present invention should be interpreted by the claims below, and all technical spirits within the scope equivalent thereto should be interpreted as being included in the scope of the present invention.

10: compressor 11: outlet
12: low pressure suction unit 13: medium pressure suction unit
14: four sides 15: indoor heat exchanger
18: outdoor heat exchanger 21: discharge piping
23: 1st connection pipe 24: 2nd connection pipe
26: suction piping 27: accumulator
31: steam injection inlet pipe 32: steam injection outlet pipe
33: steam injection expansion valve 34: bypass inlet pipe
35: bypass outlet piping 36: bypass valve
40: supercooling heat exchanger 41: outer piping
42: inner piping 43: bulkhead
44: steam injection flow path 45: bypass flow path
51: first entrance 52: first exit
53: second entrance 54: second exit
55: 3rd entrance 56: 3rd exit
60: gas-liquid separation member 61: connecting tube
62: large neck part 63: small neck part
64: separation tube 65: connection
66: return unit 80: controller

Claims (15)

delete delete delete delete delete Outer piping;
At least one inner pipe disposed inside the outer pipe;
A partition wall disposed in the outer pipe and penetrated by the inner pipe;
A steam injection channel formed between an inner surface of the outer pipe and an outer surface of the inner pipe and located on one side of the partition wall;
A bypass channel formed between an inner surface of the outer pipe and an outer surface of the inner pipe and located on the other side of the partition wall;
A first connecting pipe communicating the inner pipe with the indoor heat exchanger;
A steam injection inlet pipe branched from the first connection pipe and communicating with the steam injection flow path;
A steam injection expansion valve installed in the steam injection inlet pipe;
A steam injection outlet pipe communicating the steam injection passage with a suction portion of the compressor;
A second connecting pipe communicating the inner pipe with an outdoor heat exchanger;
A gas-liquid separating member separating the gas phase refrigerant and the liquid refrigerant in the outdoor heat exchanger;
A bypass inlet pipe communicating the gas-liquid separation member and the bypass channel;
A bypass outlet pipe communicating the bypass channel with the suction part of the compressor;
A bypass valve installed in the bypass inlet pipe or bypass outlet pipe; And
An air conditioning system including a controller that closes the bypass valve during a cooling operation in which refrigerant is condensed in the outdoor heat exchanger. The method of claim 6,
The bypass outlet pipe is an air conditioning system connected between the suction part of the compressor and the accumulator with respect to the flow direction of the refrigerant. The method of claim 6,
With respect to the flow direction of the refrigerant, the length of the steam injection passage is longer than that of the bypass passage. The method of claim 6,
The gas-liquid separation member,
A connection tube formed elongated in one direction and connected to the bypass inlet pipe; And
And a separation tube connected to the connection tube and forming a return band of the outdoor heat exchanger. The method of claim 9,
The separation tube,
A connection portion to which the connection tube is connected and formed long in the one direction; And
An air conditioning system comprising a return portion branched from the connecting portion. The method of claim 10,
The connecting tube,
A large diameter part connected to the bypass inlet pipe; And
An air conditioning system including a small diameter part inserted into the connection part and having an outer diameter smaller than the inner diameter of the connection part. The method of claim 6,
The suction part of the compressor,
A low pressure suction part to which the steam injection outlet pipe is connected; And
An air conditioning system including a medium pressure suction part spaced apart from the low pressure suction part and connected to the bypass outlet pipe. The method of claim 6,
The controller,
When the heating operation in which the refrigerant is evaporated in the outdoor heat exchanger, the air conditioning system opens the bypass valve when the frequency of the compressor is greater than the set frequency. The method of claim 6,
Further comprising an evaporation temperature sensor for measuring the evaporation temperature of the outdoor heat exchanger,
The controller,
When the heating operation in which the refrigerant is evaporated in the outdoor heat exchanger, the air conditioning system opens the bypass valve when the frequency of the compressor is greater than the set frequency and the temperature measured by the evaporation temperature sensor is equal to or less than the preset temperature. The method of claim 6,
Further comprising an accumulator in communication with the suction portion of the compressor,
The bypass inlet pipe,
A first inlet pipe portion connecting the gas-liquid separation member and the accumulator; And
An air conditioning system including a second inlet pipe portion connecting the accumulator and the bypass flow path.

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