Using a modified Einstein-Szilard cooling cycle, a Air-Conditioning system works by Solar Heating (and a little Photovoltaic power as well).
A large Frensel Lense Solar Concentrator is installed onto the roof a a high typically Sunlit building. This heats one part of the cooling loop, this heat energy is used as a part of a Gas-Exchange cooling system that is used to cool a large volume of otherwise hot air.
The main idea of this is not to replace all electical AC units but to surplant them on very sunny / hot days where Solar Heat is abundant and Electricity not so.
The Hotter it is, the colder the output air will be.
The system being a modified version of the Einstein cycle can run entirely on heat (solar) alone. However I think it would be best to replace the inefficient heat pump with a traditional motor pump (also solar powered).-- Melchior, Mar 29 2007 CYCLE THERMODYNAMIC MODEL http://www.me.gatec.../andy_phd/three.htm [nuclear hobo, Mar 29 2007] gas-powered fridge http://www.cam.net....lda/electrolux.html [nuclear hobo, Mar 29 2007] brilliant. [+]-- CaptainClapper, Mar 29 2007 I'll take two, no make that three. [+]-- nuclear hobo, Mar 29 2007 I may be wrong, but it seems that as the bubble pump uses a small proportion of the total power, its inefficiency is more than made up for by the total lack of moving parts; a //traditional motor pump// would create the need for rotary seals or a sealed motor unit, which would require breaking of seals for maintenance.-- spidermother, Jan 27 2009 sp. "Fresnel lens"-- coprocephalous, Jan 27 2009 random, halfbakery