Patent ID: 6826924
Filing Date: 2004-12-07
Classification: F25B,Y02B

Abstract:
A heat pump apparatus comprising a refrigerant circuit (15) in which a plurality of utilization side circuits (60, 65) having respective utilization side heat exchangers (61, 66) and utilization side expansion mechanisms (62, 67) are each connected in parallel to a heat source side circuit (20) having a compressor (41, 42), a heat source side expansion mechanism (24), and a receiver (23),wherein: said heat pump apparatus performs at least a heating operation for allowing refrigerant, condensed by each of said utilization side heat exchangers (61, 66) in a refrigeration cycle in which refrigerant circulates in said refrigerant circuit (15), to flow into said receiver (23), said receiver (23) is provided upstream of said heat source side expansion mechanism (24) in the direction of the flow of refrigerant during heating operation, said heat pump apparatus further comprises: a communicating passageway (35) for directing gaseous refrigerant in said receiver (23) to a suction side of said compressor (41, 42), a switching mechanism (36) for establishing and interrupting flow of gaseous refrigerant in the communicating passageway (35), and controlling means (90) for controlling said switching mechanism (36) so that gaseous refrigerant within said receiver (23) is sucked into said compressor (41, 42) to reduce the internal pressure of said receiver (23) during the heating operations, said receiver (23) of which internal pressure is reduced sucks refrigerant from said respective utilization side heat exchangers (61, 66) during the heating operation.