I just came across this amazing contraption. It's a solar powered Sterling engine that generates electricity, hot water, heating, and and absorption chiller for air conditioning. I saw it in Solar Today magazine. It is a wild, almost Dr. Seuss-like contraption that generates electricity through solar thermal. A Sterling engine works on thermal expansion and compression of a fluid in a closed system, unlike a steam engine which relies on pressure to fill and push a cylinder and is then exhausted. The system is called DiGeSPo - Distributed combined heat and power Generation from small size concentrated Solar Power. It uses an evacuated solar tube collector with a parabolic concentrator for the heat source. Pretty nifty. Apparently there are two sizes, a 1-3 kW and a 3-6 kW. Not yet on the market. I also don't know the heating and cooling output.