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ISSN Online: 2377-424X

ISBN CD: 1-56700-226-9

ISBN Online: 1-56700-225-0

International Heat Transfer Conference 13
August, 13-18, 2006, Sydney, Australia

NUMERICAL STUDY OF NATURAL CONVECTION HEAT LOSS IN MODIFIED CAVITY RECEIVER FOR FUZZY FOCAL SOLAR DISH CONCENTRATOR

Get access (open in a dialog) DOI: 10.1615/IHTC13.p24.180
10 pages

Résumé

High temperature heat production for electricity generation often requires direct absorption of solar energy. Cavity receivers are normally used to increase the absorption of the reflected solar radiation with minimum heat loss. In this paper a numerical study is presented to investigate the most predominant convection heat loss from modified cavity receiver of a fuzzy focal solar dish concentrator. The influence of operating temperature, orientation and the geometry on the total heat loss from the receiver was investigated. The effect of operating temperatures varying from 300°C to 700°C on heat loss for different orientations of the receiver was studied. The convection loss of the modified receiver was estimated at inclination varying from 0° (cavity aperture facing sideways) to 90° (cavity aperture facing down). The convection heat loss is maximum at 0° and decreases monotonically to 90°. The results of numerical analysis is presented with a correlation for the Nusselt Number, NuD = 0.0124 GrD0.2623(1 + cosθ)4.586(TR)−0.0319. The influence of aperture ratio on the heat loss was carried out and it is found that beyond Aw/A1 = 8, the variation in losses are insignificant. The total heat loss, which includes conduction, convection and radiation, was estimated with various receiver positions. The comparison of present numerical study with other well-known models is carried out. The present numerical study predicts low convection heat loss than the other models. The modified cavity receiver may effectively be used for fuzzy focal solar dish concentrator.