Patent ID: 7520320

Claim:
An automotive air conditioning system comprising: a primary hot water circuit which includes a heat generator installed in a vehicle and through which a coolant which cools the heat generator flows; a secondary hot water circuit which includes a hot water type heater core which heats passenger compartment outlet air and in which the coolant flows through the hot water type heater core; valve means adapted to be changed over between a cutting off state in which the valve means cut off the primary hot water circuit from the secondary hot water circuit and a connecting state in which the valve means connect the primary hot water circuit with the secondary hot water circuit; a coolant-refrigerant heat exchanger provided on a discharge side of a compressor along a refrigeration cycle (R) for heating the coolant in the secondary hot water circuit by virtue of heat dissipation from a high-pressure refrigerant on the discharge side of the compressor; and a primary control means for controlling the valve means by comparing a coolant temperature (TW 1 ) of the primary hot water circuit with a coolant temperature (TW 2 ) of the secondary hot water circuit; wherein the primary control means controls such that the valve means are put in the cutting off state when the coolant temperature (TW 1 ) of the primary hot water circuit is lower than the coolant temperature (TW 2 ) of the secondary hot water circuit, whereas when the coolant temperature (TW 1 ) of the primary hot water circuit becomes higher than the coolant temperature (TW 2 ) of the secondary hot water circuit, the valve means are put in the connecting state.