METHOD FOR OPERATING A COOLANT CIRCUIT AND VEHICLE AIR-CONDITIONING SYSTEM

A method for operating a coolant circuit of a vehicle cooling system in an AC mode and in a heating mode, implemented by a heat pump function, having an evaporator branch including an evaporator and a first expansion element, a coolant compressor, an AC and heat pump branch, having an outer condenser or gas cooler, as a heat pump evaporator having a second expansion element. The AC and heat pump branch is connected to the coolant compressor via a first blocking element and to the evaporator branch via the second expansion element, a heating branch having an inner heating condenser or heating gas cooler and a second blocking element, connected downstream thereto.