Abstract: The bleed air requirements for a pressurization and environmental control system for the cabin (10) of an aircraft may be reduced by a system that includes a turbomachine (20) having a rotary compressor (22) driven by a turbine wheel (26). A ram air inlet (16) is connected to the compressor inlet (28) and the aircraft is provided with a cabin air exhaust port (18) which is connected to the outlet (34) of the turbine wheel (26). A heat exchanger (40) has a cabin inlet air flow path (42) and a cabin outlet air flow path (44) in heat exchange with one another. The cabin inlet air flow path (42) is connected to the outlet (30) of the compressor (22) and to the cabin (10) of the aircraft. The cabin outlet air flow path (44) is connected to the cabin (10) as well as to the inlet (32) of the turbine (26).

Abstract: Improved cooling of electronic heat loads aboard aircraft is achieved in a system including a sealable aircraft cabin (10), first and second electronic heat loads (38), (40) and a means (42) for maintaining a desired pressure within the cabin (10). A rotatable turbine wheel (16) is associated with an overboard dump port (32) such that air being dumped overboard from the cabin is expanded to rotate the turbine wheel (16). A mechanical load (20) is connected to the turbine wheel (16) for harnessing the rotation thereof and means (24), (60) are employed for using the air expanded by the turbine wheel (16) for cooling at least one of the loads (38), (40).