> There are small bar fridges which have no compressors nor any Peltier
 > devices either. They seem to have an external heating element and
 > circulate some coolant which pumps heat away from the inside. They 
 > are absolutely quiet and can even achieve freezing temps in a small
 > compartment. I just wondered if this sort of simple heat pump system
 > could be expanded to a larger scale?
I used to work at a place that cooled entire buildings with these sort of 
outfits. They're called 'Absorbtion' refrigeration units. But as I mentioned, 
they don't work very well with low temperatures such as from a simple solar 
system. They WILL work with reflective solar arrays that track the sun or 
otherwise provide high temperatures throughout much of the day.
One large problem with solar powered A/C is the fact that you need it for 
lots longer than just the real sunny part of the day. There's ways of storing 
heat, but again, it's usually low-grade and unsuitable for driving an A/C 
unit.
--- FLAME v1.1
---------------