EMPLOYING EXERGY-OPTIMIZED PIN FINS IN THE DESIGN OF AN ABSORBER IN A SOLAR AIR HEATER

The performance of a solar air heater is primarily based on the design of the absorber plate and a substantial fraction of the cost of the heater is covered by the cost of the absorber plate. Heat transfer augmentation features for the improvement of heat transfer from the plate to the working fluid are mostly fins however these features also increase pressure drop in the flow channel. The exergy optimization philosophy is adopted in the fin sizing for this air heating application; this optimization philosophy ensures that the maximum quantity of heat is transferred by the fins while generating the least entropy in the system thus conserving exergy. Some important observations relevant in design are made.