Air conditioner

Abstract

An air conditioner includes an outdoor fan and a refrigerant circuit having a compressor, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger connected to each other. An expansion valve refrigerant discharge control, in which the compressor is driven in a state where the outdoor fan is stopped and the expansion valve is open, is performed when a cooling start noise reduction condition that a state of refrigerant at inlet and outlet ports of the expansion valve is in a one-phase liquid state is satisfied when starting the cooling operation. An expansion valve normal switching control, in which an opening of the expansion valve is reduced and an operating frequency of the compressor is increased, is performed after the expansion valve refrigerant discharge control.

1 . An air conditioner comprising:
 a refrigerant circuit including a compressor, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger connected with each other; and   an outdoor fan arranged and configured to supply outdoor air to the outdoor heat exchanger, the outdoor air being a source of cooling of refrigerant which flows through the outdoor heat exchanger,   a cooling operation being performed by driving the outdoor fan and circulating refrigerant through the compressor, the outdoor heat exchanger, the expansion valve, and the indoor heat exchanger in order,   an expansion valve refrigerant discharge control, in which the compressor is driven in a state where the outdoor fan is stopped and the expansion valve is open, being performed when a cooling start noise reduction condition that a state of refrigerant at inlet and outlet ports of the expansion valve is in a one-phase liquid state is satisfied when starting the cooling operation, and   an expansion valve normal switching control, in which an opening of the expansion valve is reduced and an operating frequency of the compressor is increased, being performed after the expansion valve refrigerant discharge control.   
     
     
         2 . The air conditioner ( 1 ) according to  claim 1 , wherein
 it is determined that the cooling start noise reduction condition is satisfied when an expansion valve reference temperature or an equivalent temperature is lower than a noise countermeasure determining temperature,   the noise countermeasure determining temperature is a threshold obtained from a temperature of the indoor heat exchanger or an equivalent temperature, and   the expansion valve reference temperature is a temperature of refrigerant at the inlet and outlet ports of the expansion valve.   
     
     
         3 . The air conditioner according to  claim 1 , wherein
 the operating frequency of the compressor in the expansion valve refrigerant discharge control is set to a noise reduction activation frequency,   the noise reduction activation frequency is lower than an activation frequency, and   the activation frequency is an operating frequency of the compressor when starting the cooling operation in a case where the cooling start noise reduction condition is not satisfied.   
     
     
         4 . The air conditioner according to  claim 1 , wherein
 the opening of the expansion valve in the expansion valve refrigerant discharge control is set to a noise reduction activation opening,   the a noise reduction activation opening is larger than an activation opening, and   the activation opening is the opening of the expansion valve when starting the cooling operation in a case where the cooling start noise reduction condition is not satisfied.   
     
     
         5 . The air conditioner according to  claim 1 , wherein
 the opening of the expansion valve is reduced before the operating frequency of the compressor is increased when switching from the expansion valve refrigerant discharge control to the expansion valve normal switching control.   
     
     
         6 . The air conditioner according to  claim 1 , wherein
 the opening of the expansion valve is reduced in a state where the operating frequency of the compressor is temporarily reduced when switching from the expansion valve refrigerant discharge control to the expansion valve normal switching control.   
     
     
         7 . The air conditioner according to  claim 1 , wherein
 the expansion valve is provided in the refrigerant circuit in a state where refrigerant flows in with a horizontal orientation and refrigerant flows out in a downward direction during the cooling operation.   
     
     
         8 . The air conditioner according to  claim 2 , wherein
 the operating frequency of the compressor in the expansion valve refrigerant discharge control is set to a noise reduction activation frequency,   the noise reduction activation frequency is lower than an activation frequency, and   the activation frequency is an operating frequency of the compressor when starting the cooling operation in a case where the cooling start noise reduction condition is not satisfied.   
     
     
         9 . The air conditioner according to  claim 2 , wherein
 the opening of the expansion valve in the expansion valve refrigerant discharge control is set to a noise reduction activation opening,   the a noise reduction activation opening is larger than an activation opening, and   the activation opening is the opening of the expansion valve when starting the cooling operation in a case where the cooling start noise reduction condition is not satisfied.   
     
     
         10 . The air conditioner according to  claim 2 , wherein
 the opening of the expansion valve is reduced before the operating frequency of the compressor is increased when switching from the expansion valve refrigerant discharge control to the expansion valve normal switching control.   
     
     
         11 . The air conditioner according to  claim 2 , wherein
 the opening of the expansion valve is reduced in a state where the operating frequency of the compressor is temporarily reduced when switching from the expansion valve refrigerant discharge control to the expansion valve normal switching control.   
     
     
         12 . The air conditioner according to  claim 3 , wherein
 the opening of the expansion valve in the expansion valve refrigerant discharge control is set to a noise reduction activation opening,   the a noise reduction activation opening is larger than an activation opening, and   the activation opening is the opening of the expansion valve when starting the cooling operation in a case where the cooling start noise reduction condition is not satisfied.   
     
     
         13 . The air conditioner according to  claim 3 , wherein
 the opening of the expansion valve is reduced before the operating frequency of the compressor is increased when switching from the expansion valve refrigerant discharge control to the expansion valve normal switching control.   
     
     
         14 . The air conditioner according to  claim 3 , wherein
 the opening of the expansion valve is reduced in a state where the operating frequency of the compressor is temporarily reduced when switching from the expansion valve refrigerant discharge control to the expansion valve normal switching control.   
     
     
         15 . The air conditioner according to  claim 4 , wherein
 the opening of the expansion valve is reduced before the operating frequency of the compressor is increased when switching from the expansion valve refrigerant discharge control to the expansion valve normal switching control.   
     
     
         16 . The air conditioner according to  claim 4 , wherein
 the opening of the expansion valve is reduced in a state where the operating frequency of the compressor is temporarily reduced when switching from the expansion valve refrigerant discharge control to the expansion valve normal switching control.   
     
     
         17 . The air conditioner according to  claim 5 , wherein
 the opening of the expansion valve is reduced in a state where the operating frequency of the compressor is temporarily reduced when switching from the expansion valve refrigerant discharge control to the expansion valve normal switching control.