Patent ID: 7028501

Claim:
An air conditioning system with a heating circuit for heating and a cooling circuit for cooling an incoming air stream for an interior compartment of a motor vehicle having an engine coolant circuit, said system including a refrigerant circuit, which includes a refrigerant compressor ( 12 ) for compressing substantially gaseous refrigerant, a switchover valve ( 13 ) arranged downstream of said refrigerant compressor ( 12 ) for directing the refrigerant compressed in said refrigerant compressor ( 2 ) selectively through one of said cooling and heating circuits, a first heat exchanger ( 14 ) arranged in said cooling circuit downstream of the refrigerant compressor ( 12 ) for dissipating heat from the refrigerant, a first expansion device ( 16 ) arranged downstream of the first heat exchanger ( 14 ), a second heat exchanger ( 15 ) arranged downstream of said first heat exchanger ( 14 ) for transferring heat from the compressed refrigerant to the expanded refrigerant before it is returned said refrigerant compressor ( 12 ), a second expansion device ( 17 ) arranged in said cooling circuit downstream of said first expansion device ( 16 ) and upstream of said second heat exchanger ( 15 ), a third heat exchanger ( 5 ) arranged in the cooling circuit between said first and second expansion devices ( 16 , 17 ), such that the pressure level of the third heat exchanger ( 5 ) can be controlled by controlling the first and second expansion devices ( 16 , 17 ) and a forth heat exchanger ( 27 ) arranged in said heating circuit for transferring heat to the engine coolant circuit when the switch-over valve ( 13 ) is set to direct the refrigerant compressed in the refrigerant compressor ( 12 ) to the heating circuit.