Vortex Tubes are another industrial cooling solution that has been used in military applications to cool very hot electronics. They're very cheap but make an enormous amount of noise that makes a Dentist's drill sound pleasant by comparison; I made one for fun... It seems to me if someone ever mates one of these with a compact air compressor and finds a way to make a compact muffler for it (most of the noise is very high frequency and easily abated) they'd have one hella cheap, powerful means for pumping heat for PC's.
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