A heat pump for space applications with a lightweight 200,000 RPM centrifugal three-stage compressor system.

Satellites have to reject waste heat into space with radiators. These radiators largely determine the size of the satellite, and a further increase in radiator size to increase the heat rejection capacity is not practical. The heat rejection capacity can also be increased by using a heat pump to increase the radiator temperature of the satellite. However, traditional compressors are too heavy (40 kg) and cause too much vibrations. For this reason, a heat pump demonstrator with a lightweight (2 kg), low-vibration, centrifugal three-stage compressor system has been developed in a project funded by the European Space Agency (ESA). Tests were carried out with the heat pump, and the measured Coefficient of Performance (COP) is 2.3, which is higher than the ESA requirement of 2. The measured isentropic efficiency of the compressor is 68%, which is higher than existing aerospace compressors and even higher than some commercially available scroll compressors.