Image collapsing concentrators. Final technical report, 1 October 1977-1 October 1980
Year: 1980
Type: report
Abstract: Wide-angle focusing Fresnel Lenses with specially curved image collapsing mirrors are developed for nontracking solar concentrators. A new type of stepped prism lens is designed with prism facets on either the inside or outer lens surface which concentrates solar radiation incident in a 60/sup 0/ elevation by 100/sup 0/ azimuth angle sectors. Thermal tests on a small model collector with a dielectric lens aperture 30 1/2 x 30 1/2 cms were conducted using a single subreflector which concentrated all acceptance zone radiation onto a fixed absorber shelf 8 cms wide. With absorbing copper tubes coated with black chrome carrying water as circulant thermal efficiencies of approximately 50% on large East West deployed solar panels are estimated. Vacuum abosrbers were also installed with improved efficiencies and operating temperatures. Segmented subreflectors were designed to increase concentration ratios from 3 to approximately 12. An economic study of the comparative cost vs performance advantages of this new technology was made. Production cost (1980) for the stepped lens - single subreflector concentrator were estimated at about $113. per meter/sup 2/ ($10.50 per ft/sup 2/). Because of the wider angular coverages, thinner structures, and sharp focusing available for larger concentration ratios, the new technology offers important advantages at lower costs over other concentrating nontracking solar collectors. A thin collector panel was studied which uses a novel internal absorber rod lens and the high thermal conductivity of copper strups for heat extraction. Thermal efficiencies and concentration ratios of about 3 are projected with important savings in collector materials.
DOI: 10.2172/6732164
Language: English
Field: Energy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W132933490