AIR CONDITIONING SYSTEM FOR AUTOMOTIVE VEHICLES AND METHOD OF OPERATING SUCH AN AIR CONDITIONG SYSTEM IN VARIOUS MODES

The subject of the invention is an air-conditioning system (1) comprising a heating, ventilation and/or air-conditioning installation (3) channelling an air flow (2), an air-conditioning loop (7) through which there circulates a refrigerant FR and a secondary loop (13), the secondary loop (13) and the air-conditioning loop (7) jointly comprising a first refrigerant/heat transfer fluid heat exchanger (12), the air-conditioning loop (7) comprising a compressor (8), a four-way valve (19), a second refrigerant/ambient air heat exchanger (14) and a thermal heat exchanger (11), the four-way valve (19) comprising a first duct (24) for circulating the refrigerant FR from the first, refrigerant/heat transfer fluid heat exchanger (12) to the compressor (8), a second duct (25) for circulating the refrigerant FR from the compressor (8) to the thermal heat exchanger (11) in a first mode of heating of the air flow (2), the four-way valve (19) comprising a third duct (26) for circulating the refrigerant FR from the compressor (8) to the first refrigerant/heat transfer fluid heat exchanger (12) and a fourth duct (27) for circulating the refrigerant FR from the second refrigerant/ambient air heat exchanger (14) to the compressor (8) in a second mode of heating of the air flow (2).