Effect of flow and geometry parameters on performance of solar air heater

Present paper deals with numerical investigation of solar air heater of a specific configuration where different geometrical parameters influencing its performance, is varied and its impact is assessed. The climatic conditions of Jeddah (lat. 21° 42' N, 39° 11'E), Saudi Arabia is considered for investigation. The numerical investigation is carried out using commercial CFD software i.e. ANSYS Fluent, as a tool of analysis. The effect of air mass flow rate, various selective coatings on the absorber plate, number of covers, spacing between the covers on the flowing air outlet temperature (Tfo) and the heater instantaneous efficiency (ηinst) are studied. The study also includes the effect of fins kept in the flow passage of heater. Investigation concludes that a better performance is expected using cobalt oxide (Co-O) as a selective coating material with a daily average of the instantaneous efficiency of about 56%. To ensure the correctness of numerical model the simulated result is validated with the analytical result that had been performed for the heater with a black painted absorber plate under the same climatic conditions.