Enclosure cooling units are equipped with a closed cooling circuit. In this circuit, the refrigerant is now under high pressure. It is cooled in the condenser and its changes from a gas to a liquid, but the high pressure remains. The constant pressure build-up of the compressor, the liquid refrigerant is forced through a capillary tube into the evaporator, thereby degrading printing and evaporated. In this case, cold is released to the environment. The cold, gaseous refrigerant is then fed back into the compressor, the circuit is closed. Due to the special operation is possible with compressor cooling devices.