OK, so the big thing is getting it to a liquid state. The change from liquid to gas is what causes the 'cold' (like a propane tank). It would be nice if the half million webpages devoted to 'how an a/c works' would say that instead of just detailing the refrigerant going from device to device in a loop.
I was trying to find a pressure vs. temperature curve for R134a, but I couldn't find one. Do you know what temperature it has to be at while maintaining atmospheric pressure to turn into a liquid (i.e. without compressing it)?
I'm wondering if there is a substance that will compress easier than R134a (for efficiency purposes) or if that's the best option.
O6, did you mean that you can boil water at less than 100C if you
raise the pressure? Hence the reason why Denver has a harder time boiling water and a pressure cooker has an easier time.