Air conditioner and outdoor unit therefor

An outdoor unit for an air conditioner comprising:

• a compressor;
• an outdoor heat exchanger which exchanges heat between a refrigerant and external air;
• a four-way valve located proximate the compressor which circulates a refrigerant according to a heating cycle or a cooling cycle;
• a first refrigerant path which connects the outdoor heat exchanger to an indoor unit;
• a second refrigerant path which connects the four-way valve to the indoor unit;
• a refrigerant detouring paths connected to the first refrigerant path by a first three-way valve and connected to the second refrigerant path by a second three-way valve, which detours a refrigerant at the time of a defrosting cycle;
• an outdoor expansion device installed in the middle of the refrigerant detouring path which lowers a pressure of a refrigerant which flows in the refrigerant detouring path;
• and
• a heat exchanging device installed between the outdoor expansion device and the second three-way valve, which exchanges heat between a refrigerant discharged from the compressor and a refrigerant which has passed through the outdoor expansion device.

An air conditioner comprising:

• an indoor unit provided with an indoor heat exchanger and an indoor expansion device;
• and
• an outdoor unit comprising:
• a compressor which compresses a refrigerant;
• an outdoor heat exchanger which exchanges heat between a refrigerant and an outdoors;
• a four-way valve located proximate to the compressor, which circulates a refrigerant discharged from the compressor according to either of a heating cycle or a cooling cycle;
• a refrigerant detouring path which detours a refrigerant discharged from the outdoor heat exchanger to the compressor at the time of a defrosting operation;
• an outdoor expander installed in the middle of the detouring path which reduces a pressure of a refrigerant which flows in the refrigerant detouring path;
• and
• a heat exchanger installed in the middle of the detouring path, which directly exchanges heat between a refrigerant introduced from the outdoor expander and a refrigerant discharged from the compressor, said heat exchanger comprising:
• an inlet which introduces a refrigerant from the four-way valve;
• a heat exchanger extension extending from the inlet portion with an expanded volume to accommodate the refrigerant detouring path therein so which direct heat exchange occurs between a refrigerant passing through the detouring path and a refrigerant introduced through the inlet portion;
• and
• an outlet which discharges a refrigerant which has passed through the heat exchanging portion to the outdoor heat exchanger.