HEAT-PUMP VEHICULAR AIR CONDITIONER AND DEFROSTING METHOD THEREOF

摘要

Provided is a highly reliable heat-pump vehicular air conditioner that can be easily installed at low cost and that permits sharing of circuit components having the same pressure conditions as those of the original cooling cycle. The original refrigeration cycle (16) for cooling comprises: an interior condenser (8) connected to the discharge circuit of an electric compressor (9) and placed on the downstream side of an interior evaporator (7) for an HVAC unit (2), a first heating circuit (18) connected to a receiver (11) via switching means (17) provided to the intake side of the exterior condenser (8), and a second heating circuit (23) connected between the outlet side of the receiver (11) and the intake side of the electric compressor (9) and provided with a sec- ond expansion valve (20) and an exterior evaporator (21). A heat pump cycle (24) for heating comprises the electric compressor (9), the interior condenser (8), the switching means (17), the first heating circuit (18), the receiver (11), and the second heating circuit (23) having the second expansion valve (20) and the exterior evaporator (21).