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Title: An improved technique for computing the top heat loss factor of a flat-plate collector with a single glazing

A different approach to evaluate the top heat loss factor of a flat plate solar collector with a single glass cover is proposed. The equation for the heat loss factor in the analytical form is employed instead of the semi-empirical form hitherto employed for solar collectors. The glass cover temperature is, however, estimated by an empirical relation. (This relation replaces the empirical relation for the factor f of the earlier work). Values of the top heat loss factor calculated by this simple technique are within 3 percent (maximum error) of those obtained by iterative solution of the heat balance equations. There is an improvement in accuracy by a factor greater than five over the current semi-empirical equations. The range of variables covered is 50/sup 0/C to 150/sup 0/C in absorber plate temperature, 0.1 to 0.95 in absorber coating emittance, and 5 W/m/sup 2/C to 45 W/m/sup 2/C in wind heat-transfer coefficient. The effect of variation in air properties with temperature has been taken into account.
Authors:
;
Publication Date:
OSTI Identifier:
6429940
Resource Type:
Journal Article
Resource Relation:
Journal Name: J. Sol. Energy Eng.; (United States); Journal Volume: 110:4
Research Org:
Centre for Energy Studies, Indian Institute of Technology, Delhi, New Delhi 110 016 (IN)
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 42 ENGINEERING; FLAT PLATE COLLECTORS; HEAT LOSSES; AIR; ANALYTICAL SOLUTION; CALCULATION METHODS; DESIGN; EQUATIONS; GLAZING; ITERATIVE METHODS; VARIATIONS; COVERINGS; ENERGY LOSSES; EQUIPMENT; FLUIDS; GASES; LOSSES; SOLAR COLLECTORS; SOLAR EQUIPMENT 141000* -- Solar Collectors & Concentrators; 420400 -- Engineering-- Heat Transfer & Fluid Flow