DESIGN AND PERFORMANCE-CHARACTERISTICS OF A PARABOLIC-TROUGH SOLAR-COLLECTOR SYSTEM

A comparison of the advantages and disadvantages of concentrating coll ectors against conventional flat-plate collectors are presented. This is followed by the design of a parabolic-trough solar-collector system , due consideration having been given to collector-aperture and rim-an gle optimisation, together with the receiver-diameter selection. The c ollector characteristic curve gives a test slope of 0.441 and a test i ntercept equal to 0.642. The value of the test slope differs considera bly from the initially predicted value: this is attributed to the heat losses from the receiver support brackets. Subsequent allowance for t hese losses is presented: this reduces the difference from 24.9% to 5. 7%. Other tests are presented, including the determination of the coll ector's incidence-angle modifier, time constant and acceptance angle.