Having a supercooling refrigerant, defrosting heating function and a control method for an air conditioning system

The present invention discloses a refrigerant subcooling, air conditioning systems and heating function defrosting control method, comprising an outdoor unit and an indoor unit, the indoor unit comprising at least one indoor unit, the outdoor unit comprising a compressor, an outdoor change heat, a four-way valve and the outdoor expansion device, the indoor unit includes an indoor heat exchanger and an indoor expansion device, the air conditioning system further comprises a heat exchange device; is provided with a heat exchange means within said first coil and a second coil; ends of the first coil of each of the outdoor expansion device, the indoor expansion device in communication; end of the second coil in communication with the outdoor expansion device, the other end of the compressor inlet end communication. The air conditioning system uses a secondary device while achieving the refrigerant subcooling, and the realization of the indoor unit for heating while defrosting during a defrosting of; the air conditioner provided with a compressor drive module connected to the module heat exchanger, the compressor energy recovery drive module while cooling.