Abstract: Thermal performance of Solar Air Heater (SAH) is low due to poor heat transfer coefficients of air. Heat transfer rates in SAH will improve by using fins, ribs/corrugations and encapsulated Phase Change Material (PCM) on its absorber plate. Amongst all placing encapsulated PCM proved as most effective passive technique to improve thermal performance of SAH. Optimization of number of capsules and their arrangement on absorber plate of SAH is required before conducting an experimental analysis on SAH. In this paper, optimum number of capsules to be placed on a SAH is analytically found. Results compared in terms of external convection heat transfer coefficient, pressure drop across SAH and friction factor.