INVESTIGATION OF THE EFFECT OF BOOSTERS ON THE PERFORMANCE OF DOUBLE EXPOSURE FLAT PLATE COLLECTOR

Abstract

Conventional design for flat plate collectors have always followed the pattern of exposing one side of the collector to the sun while insulating the other. However, for enhanced solar energy collection by flat plate collec-tor, non-focussing non-tracking boosters have been used for reflecting solar radiations on the exposed side. Attempts have also been made in the past to remove the rearside insulation of the flat plate collector and reflect solar radiations by use of boosters on rearside as well as on front side. Such a system known as double exposure collector system i`s expected to affect enhanced solar energy collection as compared to a simple flat plate collector of same size under similar, conditions of insula-tion, ambient air temperature and mass flow rate. In this work, a double exposure collector system based on the geometry proposed by Larson and Savery [7] has been designed and fabricated for Roorkee location (latitude - 29.85°N). The performance of double exposure collector system has been investigated analytically and experimentally. The performance factor has been evaluated experimentally for double exposure collector with and without side boosters. It has been observed that the peak enhancement of energy yield Is around noon and is about 60 percent more than reference collector when the double exposure collector is not provided with side boosters. (iv) The offnoon performance is not so encouraging. With the usc. of side boosters with double exposure collector, the enhancement of energy collection is around + 30 degree hour angle and -30 degree hour angle. The maximum rate of energy collection is about 120 percent more than that by reference collector. However, the performance around noon remains uneffected. The performance factor is a strong function of geometry of double exposure collector and time of the day.