Air-conditioning system

摘要

An air-conditioning system capable of always effectively performing the heating function by selectively using one of a cooling circuit and a heating circuit sharing a variable displacement type compressor is disclosed. An electromagnetic capacity control valve (43) controls the discharge capacity of a variable displacement type compressor (25) in response to the differential pressure between the discharge pressure Pd of a discharge chamber (132) and the suction pressure Ps of a suction chamber (131). The energization and deenergization of the capacity control valve (43) is controlled by a control unit (59). When a cooling command switch (63) is turned on, the control unit (59) deenergizes a switching valve (29) thereby to control the cooling operation while at the same time controlling the discharge capacity by the capacity control valve (43). When a heating command switch (64) is turned on, on the other hand, the control unit (59) energizes the switching valve (29) thereby to control the heating operation while at the same time controlling the discharge capacity by the capacity control valve (43).