Boy's q does seem to suggest he might be mistaken in the effect of pressure upon temp
In fact I seem to recall that once compressed the air does indeed return to its former lower temp so I'm wondering if this is what motivates his uncertainty
Mon 19 Aug, 2013 09:31 am
It's a fairly straightforward phenomenon. If you compress a gas then the heat energy that was contained in the previous volume is now contained in a smaller volume thusly raising the temp of the smaller volume. If you now allow the smaller volume to cool and then allow it to expand it will be cooler than the previous small volume was.
Air conditioners and heat pumps use this. Its more efficient to use a refergerant gas (easily liquified) to do this.