Small Stirling-cycle Power Sources in Marine Applications

A paper presented at the 1974 Conference (Ref 1) described the development of a Stirling-cycle thermo-mechanical generator (TMG) for providing small amounts of electrical power continuously over long periods, while requiring much less fuel than other power sources running from hydrocarbon fuel or radio-isotopes. Two of these 25-Watt generators, fuelled by propane, have been used to power the UK National Buoy on two successive missions. A total of more than three years experience at sea has now been accumulated. In addition, a 60-watt version has provided the power for a major lighthouse for more than a year. An early development version of the Thermo-mechanical Generator, adapted to run from the heat of a radio-isotope source, was loaded with strontium-90 titanate in October 1974 and has run continuously in the laboratory ever since. The Paper describes the improvements and changes found necessary in the course of 90,000 generator-hours of running time, and outlines the improvements in operational performance and reliability which have resulted.