Experimental Analysis of a Single-Flow Double-Channel Solar Air Heater Under Forced and Natural Convection Conditions

E. El-Bialy

Abstract: This study presents an experimental evaluation of a single-flow double-channel solar air heater (SFDC-SAH) tested under both forced and natural convection modes. The SFDC-SAH, designed with two separate air channels and a copper absorber plate, was assessed outdoors for thermal performance across varying air mass flow rates. Results indicate that higher mass flow rates significantly enhance useful heat gain and thermal efficiency, with forced convection achieving up to 2.48 times greater efficiency compared to natural convection. A cost analysis further reveals that forced convection offers the most cost-effective energy output.

Keywords: Solar air heater, Forced convection, Natural convection, Thermal efficiency and Heat gain