Aircraft Environmental Control System (ECS) Pressurisation and Air conditioning System PAC
Here is using a re-
System Diagram: Hot pressurised air (180 degrees C and 38 PSI) is provided by a
gas turbine engine. The gas turbine engine features an over-
Bleed air from the APU first enters a heat exchanger that cools it using atmospheric
air that is blown through it with an electric fan. The heat exchanger is in tandem
with a second unit and receives the cooling air from it. The cooled air then enters
a small centrifugal compressor unit that raises the pressure further. Due to this
additional compression the air again becomes hot and is cooled in the second heat
exchanger that is receiving cooling air from the fan. The re-
The air exiting the system was originally drawn in to the gas turbine and heated by it’s compressor, the air now emerges colder than it went in! Water vapour contained in the atmosphere condenses out in he expanding exhaust and forms fog.
The cooling system: Two automotive inter-
The mysterious unit known as a CAU. When you sit in a plane you are breathing air that has passed through one of these. This one is fitted to Tornado fighter jet and was part of the cockpit and avionics cooling system.
The CAU consists of a centrifugal compressor connected to a radial inflow turbine.
It is constructed a bit like an automotive turbo-
Unlike a turbo-
Centrifugal compressor unit housed in a stainless steel volute casing.
Expansion turbine unit housed in a low temperature aluminium housing.
DC motor driven blower unit with high speed axial fan. The heat exchangers would benefit from two of these.
Automotive silicone hoses fitted with V-
Two automotive inter-