Refrigeration circuit and method of operating such a

The invention relates to a refrigeration circuit (2) for a motor vehicle, with a compressor (4), a condenser (6), a first expansion valve (8) and an evaporator (10), which (S) are connected in series a refrigerant in the flow direction, with to the first expansion valve (8) a first pitch circle (14) located downstream of the compressor (4), with a second pitch circle (16) which extends downstream of the first expansion valve (8) to the compressor (4), with an internal heat exchanger (18) for transferring heat from the first pitch circle (14) in the second component circuit (16). In the first part circuit (14) is a valve (26) is arranged, which is controlled by a control unit (20) to switch the internal heat exchanger (18) between a normal operation and a reduced mode, wherein a reduced in a reduced operation compared to normal operation heat transfer occurs. Such an adjustable internal heat exchanger (18) is particularly useful in a refrigeration circuit (2) is an advantage, which is operated in the manner of a heat pump in a heating mode. Furthermore, the invention relates to a method for operating a respective refrigeration circuit (2).