So the obvious question - does it work !
Well yes - a quick plumb into an airline while holding it shows that's perhaps not a good idea for a longer test - the hot end got warm very quickly
So a rough and ready test with the two exits pointing at some 50 mm squares of 9 mm plate that I happened to have on the desk, propped up with adjustable spanners let me point my infra-red thermometer at them.
After just a couple of minutes, from an ambient of 18 degrees Centigrade, the cold plate was down to 6 degrees and the hot one up to 35 degrees.
A very crude test, and no doubt the temperatures would be much more extreme if I left it going for a while, as the 50 mm squares each had a bit of a heat sink on them in the form of the adjustable spanners
In all, very interesting that plain old compressed air can heat and cool at the same time by twirling in a fancy shape !