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Electronic Resource
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SAND Report: SAND88-7035, March 1989.
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Library's review
ABSTRACT:
A stretched-membrane dish concentrator design was developed in Phase I of a contract directed by Sandia National Laboratories, Albuquerque. The concentrating optical element was investigated in detail, and conceptual designs were provided for the collector support system. The optical
A stretched-membrane dish concentrator design was developed in Phase I of a contract directed by Sandia National Laboratories, Albuquerque. The concentrating optical element was investigated in detail, and conceptual designs were provided for the collector support system. The optical
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element was defined by a monolithic, single-facet, parabolic design with an f/D ratio of 0.6. The conceptual support system was a hub and spoke structure similar to a bicycle wheel. The estimated optical element weight was 2.3 lb/ft2 (11 kg/m2), and 6.6 lb/ft2 (32 kg/m2) for the entire collector. A 0.010" (0.25- mm) thick aluminum diaphragm was plastically deformed without the use of a mold or mandrel to create the optical membrane. This free-form yield process was demonstrated with 1.4-m and 3.7-m diameter tests. The one-sigma slope error of these test membranes, based on a peak flux bound, was less than 2 mrad at the smaller scale, and less than 4 mrad at the larger scale. The aluminum membrane defined the concentrator shape for a separate, reflective polymer film membrane. Contact between the two membranes was maintained with a vacuum. The stretched-membrane dish technology, applied to a parabolic dish, demonstrated the potential for high performance with low weight. Show Less