INVESTIGATION OF OPTIMUM CONDITIONS FOR A SOLAR AIRHEATER WITH PACKED BED DUCT

Abstract

Conventional flate plate collectors have been found to have low thermal efficiency because of low heat transfer coefficient between the absorber plate and air. Several methods have been proposed to enhance the heat transfer coefficient. Use of packed bed in solar air heater ducts has been found to result in considerably enhanced thermal performance although some information on the thermal performance of such heater is available; but there is still a need to develop a technique at optimum design conditions. In this work, an analysis has been carried out to investigate the effect of vatriation of various design and operating parameters an efficiency. The computer program has been developed that yield a set of design parameters to result in maximum thermal efficiency using Random Search Technique. It has been found that a change in number of covers has maximum influence on performance whereas the effect of changing bed depth, equivalent diameter, porosity and bed length has been found to be small. It has also been found that there esists a single set of values of optimum design