Abstract: The invention relates to a device and a method for icing prevention regulation for a heat pump evaporator (3) in air conditioning systems of vehicles, composed of a subsection (1) of a refrigerant circuit which can be operated both as a heat pump and also as an air conditioning system. The device comprises the heat pump evaporator (3), an electrical or mechanical refrigerant compressor (4), a cooler fan (9) which is attached to the heat pump evaporator (3) and which draws ambient air (11) upstream from and through the heat pump evaporator (3) at an adjustable flow speed, and which thus permits a permanent flow of ambient air (11) over the heat pump evaporator surface, a first temperature sensor (6) in or on the refrigerant line (5, 5a) upstream from the heat pump evaporator (3) with respect to the heat pump operating direction, and a control and regulating unit (8).

Abstract: The invention relates to a device and a method for icing prevention regulation for a heat pump evaporator (3) in air conditioning systems of vehicles, composed of a subsection (1) of a refrigerant circuit which can be operated both as a heat pump and also as an air conditioning system. The device comprises the heat pump evaporator (3), an electrical or mechanical refrigerant compressor (4), a cooler fan (9) which is attached to the heat pump evaporator (3) and which draws ambient air (11) upstream from and through the heat pump evaporator (3) at an adjustable flow speed, and which thus permits a permanent flow of ambient air (11) over the heat pump evaporator surface, a first temperature sensor (6) in or on the refrigerant line (5, 5a) upstream from the heat pump evaporator (3) with respect to the heat pump operating direction, and a control and regulating unit (8).

Abstract: The invention relates to a method for operating an air conditioner (1) for treating the air of a passenger compartment of a motor vehicle. The air conditioner (1) exhibits a refrigerant circuit (2) configured for a combined cooling unit and heat-pump mode and for a post-heating mode. In the heat-pump mode with a first and a second heat source, two heat sources differing from each other can be used. A temperature of the first heat source, a temperature of the second heat source, and a regulation characteristic number and a maximum pressure are taken into account in the refrigerant circuit (2) for operating the air conditioner (1) in a heat-pump mode. The invention additionally relates to a method for switching between the two heat-pump modes.