A comprehensive review of small solar-powered heat engines: Part III. Research since 1950—“unconventional” engines up to 100 kW

Abstract In Part I of this paper, thermal devices developed up until 1950 were reviewed. In Part II, projects since 1950 with devices up to 100 kW output where the design philosophy was to use “conventional” modern technologies. In this paper, “unconventional” devices are reviewed, where the designers attempted to employ different technologies, often at the expense of performance, so as to provide devices suitable for construction and maintenance in less developed regions of the world. As in Part II, the size of devices reviewed has been limited to 100 kW, and they have been categorised by their proposed source temperature and working medium. Since solar power is most likely to be employed in remoter regions in both developed and developing countries, the devices have been reviewed in this light. At the end, the prospects of small solar engines are discussed.