The thermo-mechanical generator

Research work on thermomechanical generators based on the Stirling engine is briefly summarized. One propane-heated engine is mentioned which on a 3-day fuel consumption run consumed 22 g of fuel per hour and delivered 31.75 W ac continuously, corresponding to an overall efficiency of 10%. Such a machine would require less than a quarter of the fuel required by a typical propane-heated thermoelectric generator delivering the same power. Another machine was equipped with a nuclear radiation shield to make it suitable for heating with a strontium-90 radio-isotope heat source. Tests with the shield electrically heated show that with 180 W thermal in the radiation shield, 18 W ac at 80 Hz can be obtained at the output of the alternator. Consequently, it could be expected to obtain twice as much electrical power from a given radio-isotope source as from the same source incorporated in a thermoelectric generator.