I've been trying to wrap my head around this one for a while. What are the drawbacks to using a brayton cycle solar generation setup? Here's the setup. It seems a car turbo is the cheapest and best suited so that's what I'll prototype if the idea gets that far. Atmosphere => Compressor => Solar array => turbine => Exhaust to atmosphere. Benefits: Uses the atmosphere as the heat sink. No high temperature fluids. (low specific heat capacity for air.) Nothing environmentally controlled or hazardous. (such as ammonia or refrigerants) Cheap off the shelf components. Simple design. (No circ pumps or feed pumps.) Problems: High RPM will need to be geared down. May not have reasonable efficiency at achievable temperatures. Here are some links to bring you up to speed if you need em. Brayton cycle: http://en.wikipedia.org/wiki/Brayton_cycle A similar design that uses solar to improve efficiency: http://ec.europa.eu/research/energy/pdf/solgate_en.pdf Anything else y'all can thing of?