A vehicle air-conditioning
system includes: an
HVAC unit that blows air whose temperature has been adjusted by a
refrigerant evaporator and a second
refrigerant condenser; a
heat pump cycle in which a
refrigerant compressor, a refrigerant circuit
changeover section, a first refrigerant condenser, a first expansion valve, and the refrigerant
evaporator are sequentially connected, in which a second expansion valve and a refrigerant /
coolant heat exchanger are connected in parallel with the first expansion valve and the refrigerant
evaporator, and in which the second refrigerant condenser is connected in parallel with the first refrigerant condenser; and a
coolant cycle in which a
coolant circulating pump, a ventilation-exhaust-heat
recovery unit, a motor / battery, an electric heater, and the refrigerant / coolant
heat exchanger are sequentially connected, and in which the ventilation-exhaust-heat
recovery unit, the motor / battery, and the electric heater can be selectively used as a heat source.