On Sun, 25 May 2008 10:47:19 -0700 (PDT), Richard Kollmann
wrote:

Larry, no one suppressed the concept of using compressed air for a
cooling medium.

They used it on refrigerated ships long before the freons were even
invented. The arternatives included such hazmat as ammonia, sulfur
dioxide, and [I can see the fireball], propane. Air was the best of a
bad lot, or so many thought. Ammonia is, however, popular today for
really large refrigeration installations.

Casady