Re: Strange cooling methods: was Re: Peltier devices

Rick Walker (
Wed, 30 Mar 1994 12:22:28 -0800

> Since we're veering into physics a bit here: does anyone else
> remember the cooling device that was one of the projects in a fairly
> old collection of _Scientific American_ amateur scientist projects
> that used high pressure air and a strange funnel to create a stream of
> cooled air? I'm afraid I can't remember the details, but at the time
> it wasn't entirely clear how the cool air was produced -- there was
> some speculation about Maxwell's demon.


The device is called a Hilsch vortex tube. It looks a bit like the little
vacuum aspirators that you used in freshman chemistry. It runs off high
pressure compressed air. An internal vortex or "whirlwind" is created and
the cooler air at the center of the vortex is vented out. The hot air
is dumped out a second port. I believe that it was capable of reaching
freezing temps, but the efficiency is probably very low.