Aircraft Cooling System

The COP of the air cycle refrigeration system is quite low. Despite of this, it is employed in air craft cooling as it has the benefit of lower weight as compared to an equivalent capacity vapor refrigeration system and also since there is no requirement for an additional compressor for the cooling system as the needed compressed air can be bled from the chief compressor of the jet engine

                                                      Figure: Aircraft Cooling System

The figure shown above is the schematic diagram of a simple system employed for cooling aircraft cabins. The air bled from jet engine compressor is passed via the heat exchanger cooled by the exterior air. Such cooled high pressure air is then expanded in a small turbine. The work from the turbine can be employed to run the fan which sucks the air over the heat exchanger. The air appearing out of the turbine at low temperature is passed via the cabin. The by-pass line is employed for temperature control.