Technology Assumptions and Issues

Dish/engine systems are not now commercially available, except as engineering prototypes. The base year (1997 ) technology is represented by the 25 kWe dish-Stirling system developed by McDonnell Douglas Aerospace (MDA ) in the mid 1980's using either an upgraded Kockums 4-95 or a STM 4-120 kinematic Stirling engine. The MD A system is similar in projected cost to the Science Applications International Corporation/Stirling Thermal Motor s (SAIC/STM) dish/Stirling system, but has been better characterized. The SAIC/STM system is expected to have a peak net system efficiency of 21.9%. The SAIC/STM system uses stretched-membrane mirror modules that result in a lower intercept fraction and a higher receiver loss than the MDA system. However, the lower-cost stretched-membran e design and its improved operational flexibility are projected by SAIC to produce comparably priced systems [19].

Solar thermal dish/engine technologies are still considered to be in the engineering development stage. Assuming th e success of current dish/engine joint ventures, these systems could become commercially available in the next 2 to 4 years. The base-year system consists of a dish concentrator that employs silver/glass mirror panels. The receiver i s a directly-illuminated tubular receiver. As a result of extensive engineering development on the STM 4-120 and th e Kockums engines, near-term technologies (year 2000 and 2005) are expected to achieve significant availabilit y improvements for the engine, thus nearly doubling annual efficiency over the base year technology (from 12 to 23 %). For the years 2010 and on, systems are anticipated to benefit from evolutionary advances in dish concentrator an d engine technology. For this analysis, a 10% improvement, compared to the base-year system, is assumed based on the introduction of heat-pipe receiver technology. The introduction of advanced materials and/or the incorporation o f ceramics or volumetric absorption concepts could provide significant advances in performance compared to th e baseline. Favorable development of advanced concepts could result in improvements of more than an additional 10%. However, because there are no significant activities in these areas, they are not included in this analysis.

The system characterized is located in a region of high direct normal insolation (2.7 MWh/m 2/yr), which is typified by the Mojave Desert of Southern California. Insolation is consistent with desert regions throughout the Southwest United States.

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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