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Study of Umbrella-Type Erectable Paraboloidal Solar Concentrators for Generation of Spacecraft Auxiliary PowerAn investigation was made of some aspects of erectable umbrella-type paraboloidal solar-energy concentrators for use in spacecraft auxiliary power systems. An analysis is presented for the design of concentrators employing radial ribs and membrane-type coverings. The rib stiffness necessary to give a desired parabolic curvature upon erection is determined. Rib contour measurements were made in an upright and inverted position on an experimental 10-foot-diameter concentrator giving a focal length of 30.78 inches and 30.6 inches, respectively, as compared with a design focal length of 30 inches. Calorimetric tests employing spherical heat receivers showed a maximum geometrical concentrator efficiency of 75.3 percent with a concentration ratio of 92.2 at a focal length of approximately 30.5 inches. Within the scope of this investigation, it was found that, as the concentrator size increases, the weight per unit projected area increases, time to damp to one-half amplitude increases, and the natural frequency decreases. Umbrella-type solar concentrators appear to be feasible for power conversion systems using low concentration ratios; however, for large concentrators the time required to damp out disturbances may be a problem.
Document ID
19620004070
Acquisition Source
Headquarters
Document Type
Other - NASA Technical Note (TN)
Authors
Benson, Harold E. (NASA Langley Research Center Hampton, VA, United States)
Nowlin, William D. (NASA Langley Research Center Hampton, VA, United States)
Date Acquired
August 1, 2013
Publication Date
August 1, 1962
Subject Category
Communications And Radar
Report/Patent Number
L-1945
NASA-TN-D-1368
Accession Number
62N14070
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
Keywords
SPACECRAFT
SOLAR COLLECTOR
POWER
AUXILIARY POWER SOURCE

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