Advanced Development Opportunities

Beyond the R&D required to facilitate commercialization of the industrial derivative engines discussed above, ther e are high-payoff opportunities for engines designed exclusively for solar applications. The Advanced Stirlin g Conversion System (ASCS) program administered by the National Aeronautics and Space Administration (NASA ) Lewis Research Center for DOE between 1986 and 1992, with the purpose of developing a high-performance free -piston Stirling engine/linear alternator, is an example of a high-risk high-payoff development [20]. An objective o f the ASCS was to exploit the long life and reliability potential of free-piston Stirling engines.

Thermodynamically, solar thermal energy is an ideal match to Stirling engines because it can efficiently provide energy isothermally at high temperatures. In addition, the use of high-temperature ceramics or the development o f "volumetric" Stirling receiver designs, in which a unique characteristic of concentrated solar flux is exploited, are other high-payoff R&D opportunities. Volumetric receivers exploit a characteristic of solar energy by avoiding the inherent heat transfer problems associated with conduction of high-temperature heat through a pressure vessel. Volumetri c receivers avoid this by transmitting solar flux through a fused silica "quartz" window as light and can potentially work at significantly higher temperatures, with vastly extended heat transfer areas, and reduced engine dead volumes, whil e utilizing a small fraction of the expensive high-temperature alloys required in current Stirling engines. Scoping studies suggest that annual solar-to-electric conversion efficiencies in excess of 30% could be practically achieved wit h potentially lower cost "volumetric Stirling" designs. Similar performance enhancements can also be obtained by th e use of high-temperature ceramic components.

Solar Stirling Engine Basics Explained

Solar Stirling Engine Basics Explained

The solar Stirling engine is progressively becoming a viable alternative to solar panels for its higher efficiency. Stirling engines might be the best way to harvest the power provided by the sun. This is an easy-to-understand explanation of how Stirling engines work, the different types, and why they are more efficient than steam engines.

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