1987 GM Aero 2003A concept

[aerohead]

Originally Posted by cRiPpLe_rOoStEr

Makes me wonder how an aviation-inspired air-cycling setup, instead of the more usual vapor-cycling air conditioner, could lead to further improvements to the aerodynamics. Or if that wouldn't be doable at all... AFAIK the only road-going vehicles featuring some sort of air-cycling conditioner are some coaches, due to Covid-related regulations which prompted coachbuilders to resort to this in order to decrease the risk of contamination, yet I'm not sure how effective it is.

I'm given to understand that, they use air as the working fluid because there's available surplus power from the compressor section of the jet-turbines, and if the system were to somehow spring a leak, only 'air' would contaminate the passenger cabin and cockpit.
Some refrigerants are both flammable, explosive, and toxic, especially in confined spaces, like an aircraft.

[Piotrsko]

Air Conditioning

According to this, there's a small cooling system for hot day low level cooling requirements when not attached to GPU. At altitude, you need heat and it only takes about 5 minutes to get to that heat requirement.

[cRiPpLe_rOoStEr]

Even though heat may be required, and the air-cycling system can provide it quite easily from the engine compressors, the same operating principle can be also used for cooling.

Originally Posted by aerohead

I'm given to understand that, they use air as the working fluid because there's available surplus power from the compressor section of the jet-turbines, and if the system were to somehow spring a leak, only 'air' would contaminate the passenger cabin and cockpit.
Some refrigerants are both flammable, explosive, and toxic, especially in confined spaces, like an aircraft.

Not to mention it also supplies the pressurization system.