PURPOSE: To enable execution of partial heating during cooling operation and to enable execution of partial cooling during heating operation by a method wherein a high and low pressure flow rate regulating valve is located in a high and low pressure bypass circuit bypassing the delivery pipe and the suction pipe of a compressor, and the opening of the high and low pressure flow rate regulating valve is regulated according to the detecting value of a pressure detector.
CONSTITUTION: When, during cooling operation, partial heating is effected, a high pressure high temperature refrigerant compressed by a compressor 2 dissipates heat through a four-way valve 3 with the aid of a heat exchanger 5 on the outdoor side for condensation to produce a high pressure liquid refrigerant. The liquid refrigerant is guided to an auxiliary heat exchanger 22 on the indoor side through an expansion valve 4 on the outdoor side and a two-way valve 21. The liquid refrigerant is heat exchanged with indoor air to dissipate heat, and flows through a bypass circuit 26 provided with a flow rate regulating valve 25 bypassing the auxiliary heat exchanger 22 on the indoor side. The pressure thereof is reduced by an expansion valve 23 on the indoor side, and the liquid refrigerant is heat-exchanged with indoor air to absorb heat with the aid of a main heat exchanger 24 on the indoor side for vaporization to produce a low temperature low pressure gas refrigerant, which is returned to the compressor 2. In this case, the opening of a high and low pressure flow rate regulating valve 31 of a high and low pressure bypass circuit bypassing a delivery pipe 29 and a suction pipe 30 of the compressor 2 is regulated according to the detecting pressure value of a pressure detector 32 located in the suction pipe 30 of the compressor 2.
KINO AKIHIRO
AOYAMA SHIGEO
