Solar thermal technology-outlook for the 80s

The development and application of advanced technology for improved solar thermal energy subsystems and components is being sponsored by the Department of Energy. This effort is aimed at systems that can achieve significant energy cost reductions compared with current technology. Increased efficiency has the potential for significantly lowering energy costs through reductions in the number of concentrators that must be purchased and their maintenance and operations. A net cost reduction will result, provided that higher efficiencies only impose modest cost increases on related subsystems and components. Generally, higher energy conversion efficiencies are achieved at higher temperatures and require the development of higher-temperature receivers, improved engines, and concentrators with high-quality surfaces. Development of higher-efficiency engines, receivers, concentrators, and other subsystems is being pursued by the DOE Research and Advanced Development (RandAD) program. The RandAD program is also developing potentially lower-cost, longer-life materials and expanding the application of solar thermal energy to new markets such as fuel and chemical production. It is shown that the Stirling cycle offers the greatest promise for improved efficiency for temperatures between 550 and 950/degree/C. The Brayton cycle also shows promise for high efficiency, but primarily at operating temperatures greater than 950/degree/C. 6 refs.