Is the heat difference enough to cause a noticeable power output in some type of sterling engine? Liquid nitrogen is quite cheap (alternative fuel source?)
Where would I get a 1 kilowatt (about 1 HP) Cesium source? Assuming about 1 MeV per decay, this corresponds to about 6.26 x 1015 decays per second, or 169,000 Curies. I once measured the shielding elffect of lead around a 1 milliCurie cesium source, and decided that 2 inches of lead would attenuate the radiation by about a factor of 10. So how many tons of lead are required to shield this source?Perhaps you could get radioactive waste free of charge and use that to power an engine. I think that caesium 137 will yield 1 Watt per gram. The half life in 30 years, so you can imagine a car being powered by a block of ceasium that would only have to be replaced every ten years or so.