A method for operating a motor vehicle air conditioning system as a heat pump to provide interior heating with a cold engine

摘要

The system has a conventional refrigeration circuit (20) with compressor, evaporator (24) and condenser (22) and a water filled secondary circuit having heat exchangers (60,61), radiator (50) and valves (2,3,5,6,7 by which two pumps (11,12) can circulate one of two paths (9a,10a). One circuit (9a) passes the fluid through a heat exchanger (60) and the condenser heat exchanger to provide interior heating, or the second circuit (10a) passes the fluid through the radiator and the evaporator heat exchanger to provide cooling.