US Patent 7407002 Air conditioner and outdoor unit therefor

An air conditioner comprises an outdoor unit and an indoor unit provided with an indoor heat exchanger and an indoor expansion device, wherein the outdoor unit comprises a compressor for compressing a refrigerant, an outdoor heat exchanger for heat-exchanging a refrigerant, a four-way valve adjacently arranged to the compressor for circulating a refrigerant discharged from the compressor according to a heating cycle or a cooling cycle, a refrigerant detouring path for detouring a refrigerant discharged from the outdoor heat exchanger to the compressor at the time of a defrosting operation, an outdoor expansion device installed in the middle of the detouring path for reducing a pressure of a refrigerant which flows in the refrigerant detouring path, and a heat exchanging device installed in the middle of the detouring path for heat-exchanging between a refrigerant introduced from the outdoor expansion device and a refrigerant discharged from the compressor.