Carbon dioxide as a working fluid in aircraft air-conditioning: an experimental assessment

The design of an experimental test rig for characterizing the thermal performances of a refrigerating device based on a carbon dioxide transcritical cycle for airborne application is discussed. This experimental test rig proves that the transcritical device can properly match the required specifications in order to be integrated with a conventional air–cycle machine and to realize in this way a hybrid air conditioning system for airborne application. Some practical solutions for managing the integration between the conventional system and the vapor cycle system are discussed on the basis of the experimental results.