Abstract: The invention relates to an air conditioning system for conditioning the air of a passenger space of a motor vehicle, the system including a refrigerant circuit with a compressor, a first heat exchanger for the heat exchange between the refrigerant and the environment and a second heat exchanger for supplying heat from the refrigerant to the air supply to be conditioned for the passenger space. The refrigerant circuit further includes, in the flow direction of the refrigerant after the compressor, a valve arrangement. The valve arrangement comprises a branch, a first valve arranged between the branch and the second heat exchanger, and a second valve arranged between the branch and the first heat exchanger. The first valve is designed with a normally open (NO) valve characteristic and the second valve with a normally closed (NC) valve characteristic.

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.

Abstract: The invention relates to an air conditioning system for conditioning the air of a passenger space of a motor vehicle, the system including a refrigerant circuit with a compressor, a first heat exchanger for the heat exchange between the refrigerant and the environment and a second heat exchanger for supplying heat from the refrigerant to the air supply to be conditioned for the passenger space. The refrigerant circuit further includes, in the flow direction of the refrigerant after the compressor, a valve arrangement. The valve arrangement comprises a branch, a first valve arranged between the branch and the second heat exchanger, and a second valve arranged between the branch and the first heat exchanger. The first valve is designed with a normally open (NO) valve characteristic and the second valve with a normally closed (NC) valve characteristic.