Preliminary Design Of An Advanced Stirling System For Terrestrial Solar Energy Conversion

A preliminary design was generated for an Advanced Stirling Conversion System (ASCS) that will be capable of delivering about 25 kW of electric power to an electric utility grid. The Department of Energy's (DOE) Solar Thermal Technology Program, Sandia National Laboratories (SNLA) is evaluating Stirling engines for terrestrial solar applications. As part of the DOE program, which is managed by NASA Lewis Research Center, a two-year task to complete detailed design, fabrication, assembly and testing of an ASCS prototype began in April, 1990. The ASCS is designed to deliver maximum power per year over a range of solar inputs with a design life of 30 years (60,000 hours). The ASCS has a long term cost goal of about $450 per kilowatt, exclusive of the 11-meter parabolic dish concentrator. Ile proposed system includes a Stirling engine with high-pressure hydraulic output, coupled with a bent axis variable displacement hydraulic motor and a rotary induction generator. This paper describes the major thrusts of the preliminary design, which include: 1) material selection for the hot end components, 2) heat transport system (reflux pool boiler) design, 3) system thermal response, 4) improved manufacturability, 5) FMECA/FTA analysis, 6) updated manufacturing cost estimate and 7) predicted system performance.