Air conditioner and control method thereof

Abstract

Disclosed herein are an air conditioner which controls a pressure of a refrigerant of an outdoor unit by adjusting an opening degree of an outdoor expansion valve or an indoor expansion valve, and a control method thereof. The air conditioner measures a pressure of the refrigerant discharged from a compressor during a cooling operation, and raises the pressure of the refrigerant to be higher than a designated pressure by controlling an opening degree of at least one of the outdoor expansion valve and the indoor expansion valve, if the pressure of the refrigerant is lower than the designated pressure. Further, the air conditioner measures the pressure of the refrigerant inhaled into the compressor during a heating operation, and adjusts the pressure of the refrigerant to be lower than a designated pressure by controlling the opening degree of the outdoor expansion valve, if the pressure of the refrigerant is higher than the designated pressure.

1 . A control method of an air conditioner, which has an outdoor unit including a compressor and an outdoor expansion valve, and an indoor unit including an indoor expansion valve, comprising:
 measuring a pressure of a refrigerant discharged from the compressor during a cooling operation; and   raising the pressure of the refrigerant to be higher than a designated pressure by controlling an opening degree of at least one of the outdoor expansion valve and the indoor expansion valve, if the pressure of the refrigerant is lower than the designated pressure.   
     
     
         2 . The control method according to  claim 1 , wherein the opening degree of the indoor expansion valve is controlled by adjusting a target superheat degree of the indoor unit, if the pressure of the refrigerant is lower than the designated pressure. 
     
     
         3 . The control method according to  claim 2 , wherein the opening degree of the indoor expansion valve is decreased by raising the target superheat degree of the indoor unit, if the pressure of the refrigerant is lower than the designated pressure. 
     
     
         4 . The control method according to  claim 1 , wherein the pressure of the refrigerant is raised to be higher than the designated pressure by decreasing the opening degree of the at least one of the outdoor expansion valve and the indoor expansion valve, if the pressure of the refrigerant is lower than the designated pressure. 
     
     
         5 . The control method according to  claim 1 , wherein:
 the outdoor unit further includes a receiver; and   the pressure of the refrigerant transmitted to the indoor unit is raised by transmitting high-pressure gas discharged from the compressor to the receiver, if the pressure of the refrigerant is lower than the designated pressure.   
     
     
         6 . The control method according to  claim 1 , wherein:
 a superheat degree of the refrigerant transmitted to an inlet side of the compressor is detected; and   the superheat degree of the refrigerant transmitted to the inlet side of the compressor is raised by decreasing the opening degree of the indoor expansion valve, if the superheat degree is lower than a designated reference.   
     
     
         7 . A control method of an air conditioner, which has an outdoor unit including a compressor and an outdoor expansion valve, and an indoor unit including an indoor expansion valve, comprising:
 measuring a pressure of a refrigerant inhaled into the compressor during a heating operation; and   lowering the pressure of the refrigerant to be lower than a designated pressure by controlling an opening degree of the outdoor expansion valve, if the pressure of the refrigerant is higher than the designated pressure.   
     
     
         8 . The control method according to  claim 7 , wherein an amount of the refrigerant flowing in a direction of inhaling the refrigerant into the compressor is decreased by decreasing the opening degree of the outdoor expansion valve, if the pressure of the refrigerant is higher than the designated pressure. 
     
     
         9 . The control method according to  claim 7 , wherein the opening degree of the outdoor expansion valve is controlled by adjusting a superheat degree of the indoor unit. 
     
     
         10 . An air conditioner comprising:
 a pressure sensor installed at a refrigerant outlet side of a compressor to measure a pressure of a refrigerant; and   a control unit of an outdoor unit to raise the pressure of the refrigerant to be higher than a designated pressure by controlling an opening degree of an outdoor expansion valve, if the pressure of the refrigerant is lower than the designated pressure during a cooling operation.   
     
     
         11 . The air conditioner according to  claim 10 , wherein the control unit of the outdoor unit raises the pressure of the refrigerant to be higher than the designated pressure by decreasing the opening degree of the outdoor expansion valve, if the pressure of the refrigerant is lower than the designated pressure. 
     
     
         12 . The air conditioner according to  claim 10 , further comprising a control unit of an indoor unit to raise the pressure of the refrigerant to be higher than a designated pressure by controlling an opening degree of the indoor expansion valve, if the pressure of the refrigerant is lower than the designated pressure. 
     
     
         13 . The air conditioner according to  claim 12 , wherein the control unit of the indoor unit raises the pressure of the refrigerant to be higher than the designated pressure by decreasing the opening degree of the indoor expansion valve, if the pressure of the refrigerant is lower than the designated pressure. 
     
     
         14 . The air conditioner according to  claim 13 , wherein the control unit of the indoor unit decreases the opening degree of the indoor expansion valve by adjusting a target superheat degree of the indoor unit. 
     
     
         15 . The air conditioner according to  claim 14 , wherein the control unit of the indoor unit decreases the opening degree of the indoor expansion valve by raising the target superheat degree of the indoor unit. 
     
     
         16 . The air conditioner according to  claim 10 , further comprising:
 a pressure sensor installed at a refrigerant inlet side of the compressor to measure the pressure of the refrigerant; and   a control unit of an indoor unit to receive data regarding the pressure of the refrigerant from the pressure sensor, installed at the refrigerant inlet side of the compressor, during a heating operation, and to adjust the pressure of the refrigerant to be lower than a designated pressure by controlling a target superheat degree of the refrigerant inhaled into the compressor, if the pressure of the refrigerant is higher than the designated pressure.