What would really be "cool" is Low Temperature Differential Stirling Engines. Design one that would work at 70-90oFd Diiferential (would be kinda large but light-weight) that would kick out 3,000 watts certain and continuous... would run on hot water from solar. Neat thing is, it would also run at night when air temps were a bit lower and would work very well in the winter when you'd only need to get the water to 100-120o to achieve the temperature differential. In the summer, it would have plenty of reserve power to not only turn a generator, but it could drive a second Stirling Motor backwards to make some cold air for air conditioning. Waste heat from that would make more hot water.
--Jeff Moden
Change is inevitable... Change for the better is not.