Heat-pump-type vehicle air-conditioning system

A heat-pump-type vehicle air-conditioning system comprising:

• a cooling refrigerant circuit in which an electric compressor, a vehicle exterior heat exchanger, a receiver, a first decompression means, a vehicle interior evaporator provided in an HVAC unit are connected in this order;
• a heater core that is disposed on a downstream side of the vehicle interior evaporator in the HVAC unit, and in which a heat medium including hot water is capable of being circulated;
• a refrigerant/heat medium heat exchanger that is provided in a discharge pipe of the electric compressor, and exchanges heat between the heat medium circulated in the heater core, and refrigerant gas discharged from the electric compressor;
• a heating bypass circuit having a first end connected to the discharge pipe of the electric compressor through a switching means on a downstream side of the refrigerant/heat medium heat exchanger, and a second end connected to the receiver;
• a second circuit that is connected between an outlet side of the receiver and a first end side of the vehicle exterior heat exchanger, and has a second decompression means;
• and
• a third circuit that is connected between a second end side of the vehicle exterior heat exchanger and an intake circuit of the electric compressor, and has a solenoid valve which is opened during heating, wherein
• a heating refrigerant circuit is capable of being configured by connecting the electric compressor, the refrigerant/heat medium heat exchanger, the switching means, the heating bypass circuit, the receiver, the second circuit having the second decompression means, the vehicle exterior heat exchanger, and the third circuit having the solenoid valve in this order,
• the downstream side of the refrigerant/heat medium heat exchanger is directly connected to the second end side of the vehicle exterior heat exchanger through the switching means,
• the switching means and the receiver are directly connected by the heating bypass circuit, and
• in a heating mode, when the vehicle exterior heat exchanger is frosted, the heating refrigerant circuit is switched to the cooling refrigerant circuit, and a high-temperature and high-pressure refrigerant which passes through the refrigerant/heat medium heat exchanger is directly introduced into the vehicle exterior heat exchanger, so that defrosting is possible.