KR20200058871A - Air conditioner and operating method thereof - Google Patents

Abstract

The present invention relates to an air conditioner and an operating method thereof, which determine whether a pipeline between an outdoor unit and an indoor unit is a long pipeline based on an indoor heat exchanger superheat degree and a discharge superheat degree and, when the pipeline between the outdoor unit and the indoor unit is the long pipeline, control the opening degree of an expansion valve to secure a refrigerant amount. When the current discharge temperature of a compressor is less than a target discharge temperature, the indoor heat exchanger superheat degree is equal to or greater than a first superheat degree, and the discharge superheat degree is equal to or greater than a second superheat degree, an opening degree of the expansion valve is maintained to secure a refrigerant amount.

Description

Air conditioner and its operation method {Air conditioner and operating method thereof}

The present invention relates to an air conditioner and a method for operating the same.

An air conditioner is a household appliance for maintaining indoor air in the most suitable state according to purposes and purposes. The air conditioner is driven by a refrigeration cycle that performs compression, condensation, expansion, and evaporation processes of the refrigerant, and thus can perform cooling operation of the indoor space.

Such air conditioners may be classified into a separate air conditioner in which the indoor and outdoor units are separated from each other, and an integrated air conditioner in which the indoor unit and the outdoor unit are combined into one device, depending on whether the indoor unit and the outdoor unit are separated. The outdoor unit includes an outdoor heat exchanger that exchanges heat with outdoor air, and the indoor unit includes an indoor heat exchanger that exchanges heat with indoor air.

In the case of the separated air conditioner, it is common for the indoor unit to be installed in the indoor space and the outdoor unit to be installed in the external space. At this time, the installation position of the indoor unit and the installation position of the outdoor unit may be more than a predetermined distance depending on installation conditions, installation environment, and the like.

When the piping through which the refrigerant flows between the indoor unit and the outdoor unit is a long pipe having a long distance over a predetermined distance, a method of controlling the amount of refrigerant is required because the flow rate of the refrigerant is insufficient and a pressure drop problem may occur. For example, Republic of Korea Patent Publication No. 10-2005-0075101A (published on July 20, 2005) describes a method for regulating the amount of refrigerant when the air conditioner is a long pipe.

The air conditioner according to an embodiment of the present invention and a control method thereof determine whether the piping between the outdoor unit and the indoor unit is a long pipe based on the indoor unit heat exchanger superheat and discharge superheat, and when the piping between the outdoor unit and the indoor unit is a long pipe It is intended to secure the amount of refrigerant by controlling the opening of the expansion valve.

The air conditioner according to an embodiment of the present invention determines whether the piping between the indoor and outdoor units is a long pipe according to the current discharge temperature of the compressor, the target discharge temperature, and the indoor heat exchanger superheat and discharge superheat. When the piping of is judged as a long pipe, the opening of the expansion valve is increased to a set opening to secure the insufficient amount of refrigerant.

According to an embodiment of the present invention, it is possible to determine the refrigerant circulation state based on the indoor heat exchanger superheat and discharge superheat, and when determining that the refrigerant level is insufficient, the opening of the expansion valve is adjusted to secure the refrigerant amount, thereby reducing the cooling performance. It has the advantage of minimizing and stabilizing refrigerant circulation.

In addition, the present invention has an advantage that it is possible to minimize the case where excess refrigerant flows by adjusting the opening degree of the expansion valve when it is determined that the refrigerant circulation is stabilized based on the indoor heat exchanger superheat and discharge superheat.

1 is a block diagram of an air conditioner according to an embodiment of the present invention.
2 is a flowchart of a refrigerant in an air conditioner according to an embodiment of the present invention.
3 is a control block diagram of an air conditioner according to an embodiment of the present invention.
4 is a flowchart illustrating an operation method of an air conditioner according to an 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 conditioner according to an embodiment of the present invention.

The air conditioner may include an indoor unit 1 and an outdoor unit 10.

The outdoor unit 10 includes a compressor 11 through which refrigerant passes sequentially, an outdoor heat exchanger 13 and an expansion valve 6, and the indoor unit 1 may include an indoor heat exchanger 2.

The outdoor heat exchanger 13 may include an outdoor fan 14 that includes an outdoor fan 14a that promotes heat dissipation of the refrigerant and an outdoor fan driving device 14b that rotates the outdoor fan 14a. The indoor heat exchanger 2 may include an indoor fan 3a that promotes heat dissipation of the refrigerant, and an indoor fan driving device 3b that rotates the indoor fan 3a.

The air conditioner is a compressor discharge pipe (41) connecting the compressor (11) and an outdoor heat exchanger (13), an outdoor heat exchanger discharge pipe (42) connecting the outdoor heat exchanger (13) and an expansion valve (6), It may include a liquid pipe 43 connecting the expansion valve 6 and the indoor heat exchanger 2, and an engine 44 connecting the indoor heat exchanger 2 and the compressor 11.

The air conditioner may further include an accumulator 12, and the accumulator 12 may be installed in the engine 44. The accumulator 12 is installed between the indoor heat exchanger 2 and the compressor 11 to separate the liquid refrigerant and the gaseous refrigerant, and can guide only the gaseous refrigerant to the compressor 11.

A discharge temperature sensor 32 for sensing the temperature of the refrigerant discharged from the compressor 11 may be installed in the compressor discharge pipe 41. The discharge temperature sensor 32 may be installed closer to the compressor 11 among the compressor compressor 11 and the outdoor heat exchanger 13. The discharge temperature sensor 32 may detect the compressor discharge temperature at the outlet of the compressor 11. The discharge temperature sensor 32 may detect the compressor discharge temperature through the temperature sensing element or sense the discharge pressure of the compressor 11 through the high pressure sensing element and calculate the compressor discharge temperature based on the temperature-pressure correlation. have.

The outdoor heat exchanger 13 may be provided with an outdoor unit temperature sensor 33 that detects the temperature of the refrigerant passing through the outdoor heat exchanger 13. The outdoor heat exchanger 13 may operate as a condenser condensing the compressed refrigerant, and the outdoor unit temperature sensor 33 may sense the condensation temperature of the refrigerant.

The liquid tube 43 may be provided with an indoor unit inlet temperature sensor 21 that senses the temperature of the refrigerant flowing into the indoor unit 2. The indoor unit inlet temperature sensor 21 may be installed closer to the indoor heat exchanger 2 among the indoor heat exchanger 2 and the expansion valve 6. The indoor unit inlet temperature sensor 21 may detect the indoor unit inlet temperature at the inlet of the indoor unit 2.

The engine 44 may be provided with an indoor unit outlet temperature sensor 22 that senses the temperature of the refrigerant discharged from the indoor unit 2. The indoor unit outlet temperature sensor 22 may be installed closer to the indoor heat exchanger 2 among the indoor heat exchanger 2 and the compressor 11. The indoor unit outlet temperature sensor 22 may detect the indoor unit outlet temperature at the outlet of the indoor unit 2.

In addition, the engine 44 may be provided with a suction temperature sensor 31 that detects the temperature of the refrigerant flowing into the compressor 11. The suction temperature sensor 31 may be installed closer to the compressor 11 among the compressor 11 and the indoor heat exchanger 2. The suction temperature sensor 31 may detect the compressor inlet temperature at the inlet of the compressor 11. The suction temperature sensor 31 may detect the compressor inlet temperature through the temperature sensing element, or sense the suction pressure of the compressor 11 through the low pressure sensing element and calculate the compressor inlet temperature based on the temperature-pressure correlation. have.

The indoor heat exchanger 2 may be provided with an indoor unit temperature sensor 23 that detects the temperature of the refrigerant passing through the indoor heat exchanger 2. The indoor heat exchanger 2 may operate as an evaporator for evaporating the expanded refrigerant, and the indoor unit temperature sensor 23 may sense the evaporation temperature of the refrigerant.

2 is a flowchart of a refrigerant in an air conditioner according to an embodiment of the present invention.

The refrigerant may sequentially pass through the compressor 11, the outdoor heat exchanger 13, the expansion valve 6 and the indoor heat exchanger 2.

The compressor 11 compresses the gaseous refrigerant at high temperature and high pressure, and the compressed refrigerant may flow to the outdoor heat exchanger 13 along the discharge pipe 41. The outdoor heat exchanger 13 heats the compressed refrigerant with outdoor air to condense the refrigerant, and the condensed refrigerant may flow to the expansion valve 6 along the outdoor heat exchanger discharge pipe 42. The expansion valve 6 expands the condensed refrigerant, and the expanded refrigerant may flow along the liquid pipe 43 to the indoor heat exchanger 2. The indoor heat exchanger (2) exchanges the expanded refrigerant with indoor air to evaporate the refrigerant, and the evaporated refrigerant can flow the engine (44) to the compressor (11).

Meanwhile, the indoor unit 1 is installed in an indoor space, and the outdoor unit 10 is generally installed in an external space, and the installation location of the indoor unit 1 and the outdoor unit 10 are installed depending on installation conditions, installation environment, and the like. It can go far.

As the distance between the indoor unit 1 and the outdoor unit 10 increases, the length of the liquid pipe 43 and the length of the engine 44 may increase.

The long pipe may mean a case in which the length of the liquid pipe 43 and the length of the trachea 44 are greater than or equal to a predetermined distance. That is, the liquid pipe 43 and the engine 44 may be long pipes having a length equal to or greater than a predetermined distance depending on the installation conditions or the installation environment of the air conditioner.

When the liquid pipe 43 and the engine 44 are long pipes, the air conditioner may not operate according to the set operation. For example, when the liquid pipe 43 and the engine 44 are long pipes, a pressure drop in the pipe may occur, and accordingly, the flow rate of the refrigerant decreases, so that the cooling effect decreases, and parts burn out due to abnormal operation, etc. This can happen.

Therefore, the air conditioner according to an embodiment of the present invention is to detect a pressure drop phenomenon in a pipe due to a long pipe and perform a refrigerant circulation stabilization operation when detecting a pressure drop phenomenon.

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

The air conditioner according to an embodiment of the present invention is an indoor unit inlet temperature sensor 21, an indoor unit outlet temperature sensor 22, an indoor unit temperature sensor 23, a suction temperature sensor 31, a discharge temperature sensor 32, an outdoor unit temperature sensor 33, a memory 50, an expansion valve 6 and a controller 51.

The controller 51 may be installed in any one of the indoor unit 1 and the outdoor unit 10. Alternatively, the controller 51 may be installed at a location other than the indoor unit 1 and the outdoor unit 10.

The controller 51 receives the indoor unit inlet temperature from the indoor unit inlet temperature sensor 21, receives the indoor unit outlet temperature from the indoor unit outlet temperature sensor 22, and receives the evaporation temperature of the refrigerant from the indoor unit temperature sensor 23, The inlet temperature of the compressor may be input from the suction temperature sensor 31, the compressor discharge temperature may be input from the discharge temperature sensor 32, and the condensation temperature of the refrigerant may be input from the outdoor unit temperature sensor 33.

The memory 50 may store information necessary for the operation of the air conditioner. Specifically, the memory 50 may store the target discharge temperature of the compressor 11 according to the opening amount of the expansion valve 6. For example, the memory 50 stores the target discharge temperature at 30 ° C when the opening degree of the expansion valve 60 is 10%, and the target discharge temperature at 28 ° C when the opening degree of the expansion valve 60 is 20%. It can be stored, but this is only an example for convenience of description and is not limited thereto.

In addition, the memory 50 may store first to fourth superheats for detecting a pressure drop in the pipe due to the long pipe.

The controller 51 is at least one of the indoor temperature sensor 21, the indoor temperature sensor 22, the indoor temperature sensor 23, the suction temperature sensor 31, the discharge temperature sensor 32, and the outdoor temperature sensor 33. By comparing the data sensed from one with the data stored in the memory 50, the operation of the air conditioner can be controlled, such as monitoring the operating state of the air conditioner or adjusting the opening degree of the expansion valve 6.

For example, the controller 51 includes an indoor unit inlet temperature sensor 21, an indoor unit outlet temperature sensor 22, an indoor unit temperature sensor 23, a suction temperature sensor 31, a discharge temperature sensor 32 and an outdoor unit temperature sensor ( 33) Compares the data detected from at least one of the data stored in the memory 50 to detect a pressure drop in the pipe due to the long pipe, and maintains and controls the opening of the expansion valve 6 when detecting the pressure drop You can drive.

4 is a flowchart illustrating an operation method of an air conditioner according to an embodiment of the present invention.

The controller 51 may detect the current discharge temperature of the compressor 11 (S11).

Here, the current discharge temperature may mean the temperature of the refrigerant currently discharged from the compressor 11 and may mean the temperature of the refrigerant currently flowing in the discharge pipe 41.

The controller 51 may control the discharge temperature sensor 32 to detect the current discharge temperature, and the discharge temperature sensor 32 may detect the current discharge temperature of the refrigerant discharged from the compressor 11.

The controller 51 may determine whether the current discharge temperature of the compressor is equal to or higher than the target discharge temperature (S13).

The controller 51 may compare the current discharge temperature of the compressor with the target discharge temperature, and determine whether the current discharge temperature of the compressor is equal to or higher than the target discharge temperature.

Here, the target discharge temperature is a target temperature of the refrigerant flowing in the discharge pipe 41, and may be a set temperature variable based on an operation mode, an operation state, and the like of the air conditioner.

The controller 51 can set the target discharge temperature. For example, the controller 51 sets the target discharge temperature as the first target temperature when receiving an operation command to the strong wind driving mode through the input unit (not shown) from the user, and the weak wind through the input unit (not shown) from the user. When receiving an operation command to the operation mode, the target discharge temperature may be set to a second target temperature lower than the first target temperature.

If the current discharge temperature of the compressor is equal to or higher than the target discharge temperature, the controller 51 may increase and control the opening degree of the expansion valve 6 (S15).

If the current discharge temperature of the compressor is greater than or equal to the target discharge temperature, the controller 51 may determine that the amount of refrigerant flowing is less than the amount of refrigerant flowing in the normal state.

When the refrigerant is insufficient, the refrigerant temperature rises due to overheating and excessive compression of the compressor 11 in the process of passing the compressor 11, so that the current discharge temperature discharged from the compressor 11 is greater than the target discharge temperature. Because it can rise.

Therefore, the controller 51 can increase and control the expansion valve 6 to solve the refrigerant shortage. Specifically, the controller 51 may increase the opening degree of the expansion valve 6 to the set opening degree. The controller 51 may increase the opening amount of the expansion valve 6 by a preset opening amount every predetermined time.

The controller 51 may increase and control the opening degree of the expansion valve 6 and then detect the current discharge temperature of the compressor 11 again.

Meanwhile, if the current discharge temperature of the compressor is less than the target discharge temperature, the controller 51 may determine whether the indoor heat exchanger superheat is equal to or greater than the first superheat (S17).

The controller 51 may detect the indoor heat exchanger superheat, and compare the detected indoor heat exchanger superheat to the first superheat.

Here, the indoor heat exchanger superheat may be the difference between the outlet temperature and the inlet temperature of the indoor heat exchanger (2). The controller 51 receives the outlet temperature of the indoor heat exchanger 2 from the indoor unit outlet temperature sensor 22, receives the indoor temperature of the indoor heat exchanger 2 from the indoor unit inlet temperature sensor 21, and then performs indoor heat exchange. The overheating degree of the indoor heat exchanger can be calculated by calculating the difference between the outlet temperature of the group 2 and the inlet temperature of the indoor heat exchanger 2.

Meanwhile, the first superheat degree may be a value stored in the memory 50. The memory 50 may store a first superheat degree and second to fourth superheat degrees described later.

For example, the first superheating degree may be 5 ° C or 3 ° C.

If the superheat of the indoor heat exchanger is equal to or greater than the first superheat, the controller 51 may determine whether the discharge superheat is equal to or greater than the second superheat (S19).

The controller 51 can detect the discharge superheat, and compare the detected discharge superheat with the second superheat.

Here, the discharge superheat degree may mean a value obtained by subtracting the condensation temperature of the refrigerant from the discharge temperature of the compressor 11. The controller 51 receives the discharge temperature of the compressor 11 from the discharge temperature sensor 32, receives the refrigerant condensation temperature from the outdoor unit temperature sensor 33, and then condenses the discharge temperature of the compressor 11 and the refrigerant. The discharge superheat can be calculated by calculating the difference in temperature.

The second superheating degree may be 13 ° C, 23 ° C, 25 ° C or 41 ° C, but this is only exemplary. When the first superheat degree is 5 ° C, the second superheat degree may be 13 ° C or 23 ° C, and when the first superheat degree is 3 ° C, the second superheat degree may be 25 ° C or 41 ° C.

If the discharge superheat degree is equal to or greater than the second superheat degree, the controller 51 can maintain and control the opening degree of the expansion valve 6 (S21).

That is, if the current discharge temperature of the compressor 11 is less than the target discharge temperature, and the indoor heat exchanger superheat is greater than or equal to the first superheat, and the discharge superheat is greater than or equal to the second superheat, the controller 51 may be piping due to long piping It is determined that a pressure drop phenomenon has occurred, and the opening degree of the expansion valve 6 can be maintained.

When maintaining and controlling the expansion valve 6, the controller 51 may first determine whether the expansion valve 6 is in a reduced control state or whether the expansion valve 6 is in an incrementally controlled state.

The controller 51 may maintain the current opening degree of the expansion valve 6 when the expansion valve 6 is in a reduced control state. That is, the controller 51 may stop control of reducing the opening degree of the expansion valve 6 and maintain the current opening degree. Through this, it is possible to minimize that the amount of refrigerant is reduced.

On the other hand, if the expansion valve 6 is in the state of increasing control, the controller 51 may maintain the current opening degree or maintain the increasing control state. That is, when the opening degree of the expansion valve 6 is increased, the controller 51 stops control to increase the opening degree and maintains the current opening degree, or is set every predetermined period so that the opening degree of the expansion valve 6 continues to increase. It can be increased by the amount. Likewise, it is possible to minimize the reduction in the amount of refrigerant.

When the current discharge temperature of the compressor 11 is less than the target discharge temperature, the indoor heat exchanger superheat is greater than or equal to the first superheat, and the discharge superheat is greater than or equal to the second superheat, the controller 51 minimizes the reduction of the refrigerant amount. , It can minimize the pressure drop in the pipe.

On the other hand, the controller 51 may detect the current discharge temperature of the compressor 11 again when the indoor heat exchanger superheat is less than the first superheat or the discharge superheat is less than the second superheat.

The controller 51 maintains and controls the opening degree of the expansion valve 6 and can determine whether the indoor heat exchanger superheat is less than the third superheat (S23).

The controller 51 may maintain and control the opening degree of the expansion valve 6, periodically detect the indoor heat exchanger superheat, and compare the detected indoor heat exchanger superheat with the third superheat.

Here, the third superheat degree may be smaller than the first superheat degree. For example, if the first superheat degree is 5 ° C, the third superheat degree may be 3 ° C, and if the first superheat degree is 3 ° C, the third superheat degree may be 1 ° C.

If the superheat of the indoor heat exchanger is greater than or equal to the third superheat, the controller 51 may determine whether the discharge superheat is less than the fourth superheat (S25).

Similarly, the controller 51 can maintain and control the opening degree of the expansion valve 6, periodically detect the discharge superheat, and compare the detected discharge superheat with the fourth superheat.

Here, the fourth superheat degree may be smaller than the second superheat degree. For example, if the second superheat degree is 13 ° C, the fourth superheat degree may be 12 ° C, and if the second superheat degree is 25 ° C, the fourth superheat degree may be 22 ° C. As another example, if the second superheat degree is 23 ° C, the fourth superheat degree may be 22 ° C, and if the second superheat degree is 41 ° C, the fourth superheat degree may be 38 ° C.

Also, the fourth superheat degree may be greater than the first superheat degree. For example, if the first superheating degree is 5 ° C, the fourth superheating degree may be 12 ° C or 22 ° C, and if the first superheating degree is 3 ° C, the fourth superheating degree may be 22 ° C or 38 ° C.

That is, the controller 51 periodically monitors the indoor heat exchanger superheat and discharge superheat while maintaining the opening degree of the expansion valve 6, and the indoor heat exchanger superheat is less than the third superheat or discharge superheat It can be judged whether is less than the fourth superheat.

The controller 51 may maintain the opening degree of the expansion valve 6 when the indoor heat exchanger superheat is not less than the third superheat and the discharge superheat is not less than the fourth superheat.

Meanwhile, the controller 51 may reduce and control the opening degree of the expansion valve 6 when the indoor heat exchanger superheat is less than the third superheat or the discharge superheat is less than the fourth superheat (S27).

The controller 51 may determine that the refrigerant circulation is stabilized when the indoor heat exchanger superheat is less than the third superheat or the discharge superheat is less than the fourth superheat. That is, the controller 51 may determine that the refrigerant flow rate is secured to a level capable of normal operation of the air conditioner when the indoor heat exchanger superheat is less than the third superheat or the discharge superheat is less than the fourth superheat. .

The controller 51 may control the opening of the expansion valve 6 to decrease the amount of refrigerant flowing when the indoor heat exchanger superheat is less than the third superheat or the discharge superheat is less than the fourth superheat.

Specifically, the controller 51 can reduce the opening degree of the expansion valve 6 and the setting degree. The controller 51 can reduce the opening amount of the expansion valve 6 by a set opening amount every predetermined time.

After reducing and controlling the opening degree of the expansion valve 6, the controller 51 may detect the current discharge temperature of the compressor 11 again.

That is, according to the embodiment of the present invention, the controller 51 drops the pressure in the pipe due to the long pipe based on the current discharge temperature of the compressor 11, the target discharge temperature, and the indoor heat exchanger superheat and discharge superheat. Whether a phenomenon occurs or not, and when a pressure drop occurs, the flow rate of the refrigerant may be secured through the opening control of the expansion valve 6.

According to an embodiment, the third superheat degree and the fourth superheat degree, which are comparative criteria for maintaining or controlling the opening degree of the expansion valve 6, may be determined by the first superheat degree and the second superheat degree.

Specifically, for example, when the controller 51 sets the first superheating degree to 5 ° C and sets the second superheating degree to 13 ° C, the third superheating degree is 3 ° C and the fourth superheating degree is 12 ° C. Can be. Alternatively, when the controller 51 sets the first superheating degree to 3 ° C and sets the second superheating degree to 25 ° C, the third superheating degree may be 1 ° C and the fourth superheating degree may be 22 ° C. Alternatively, when the controller 51 sets the first superheating degree to 5 ° C and sets the second superheating degree to 23 ° C, the third superheating degree may be 3 ° C and the fourth superheating degree may be 22 ° C. Alternatively, when the controller 51 sets the first superheating degree to 3 ° C and sets the second superheating degree to 41 ° C, the third superheating degree may be 1 ° C, and the fourth superheating degree may be 38 ° C.

The first to fourth superheat degrees may be set differently depending on the type of refrigerant.

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 equivalent range should be interpreted as being included in the scope of the present invention.

2: Indoor heat exchanger 6: Expansion valve
11: Compressor 13: Outdoor heat exchanger
21: indoor unit inlet temperature sensor 22: indoor unit outlet temperature sensor
23: indoor temperature sensor 31: suction temperature sensor
32: discharge temperature sensor 33: outdoor unit temperature sensor

Claims (10)

A compressor through which the refrigerant passes sequentially, an outdoor heat exchanger, and an outdoor unit having an expansion valve;
An indoor unit having an indoor heat exchanger;
A liquid pipe connecting the expansion valve and the indoor heat exchanger;
An engine connecting the indoor heat exchanger and a compressor;
An air conditioner comprising a control unit for controlling the opening degree of the expansion valve according to the current discharge temperature of the compressor, the target discharge temperature, the indoor heat exchanger superheat and discharge superheat. According to claim 1,
When the current discharge temperature of the compressor is greater than or equal to the target discharge temperature, the control unit increases the opening degree of the expansion valve to a set opening degree. According to claim 1,
If the current discharge temperature of the compressor is less than the target discharge temperature, the indoor heat exchanger superheat is equal to or greater than the first superheat, and the discharge superheat is greater than or equal to the second superheat, air conditioning to maintain the opening degree of the expansion valve group. According to claim 3,
While maintaining the opening degree of the expansion valve,
The current discharge temperature of the compressor is less than the target discharge temperature and the indoor heat exchanger superheat is less than the third superheat, which is lower than the first superheat.
If the current discharge temperature of the compressor is less than the target discharge temperature and the discharge superheat degree is less than the fourth superheat degree lower than the second superheat degree,
An air conditioner for reducing the opening degree of the expansion valve. According to claim 1,
The indoor heat exchanger superheat is an air conditioner which is a difference between an outlet temperature and an inlet temperature of the indoor heat exchanger. According to claim 1,
The fourth superheater is an air conditioner larger than the first superheater. In the operation method of the air conditioner comprising a compressor, an outdoor heat exchanger, an outdoor unit having an expansion valve and an indoor unit having an indoor heat exchanger,
Setting a target discharge temperature;
Sensing the current discharge temperature of the compressor;
Detecting an overheating degree of an indoor heat exchanger which is a difference between an outlet temperature and an inlet temperature of the indoor heat exchanger;
Detecting a discharge superheat; And
And an opening control step of controlling an opening degree of the expansion valve according to the current discharge temperature of the compressor, the target discharge temperature, the indoor heat exchanger superheat and the discharge superheat. The method of claim 7,
The opening control step
And if the current discharge temperature of the compressor is greater than or equal to the target discharge temperature, increasing the opening degree of the expansion valve to a set opening degree. The method of claim 7,
The opening control step
Maintaining the opening of the expansion valve when the current discharge temperature of the compressor is less than the target discharge temperature, the indoor heat exchanger superheat is greater than or equal to the first superheat, and the discharge superheat is greater than or equal to the second superheat. Method of operation of the air conditioner comprising. The method of claim 9,
While maintaining the opening degree of the expansion valve, the current discharge temperature of the compressor is less than the target discharge temperature and the indoor heat exchanger superheat is less than the third superheat degree lower than the first superheat degree, or the current discharge temperature of the compressor When the discharge temperature is less than the target discharge temperature and the discharge superheat is less than the second superheat, the method of operating the air conditioner further comprising the step of reducing the opening degree of the expansion valve.

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