Experimental Investigation of a Plane Air Solar Air Heater

This study extends and experimentally validates a numerical investigation on the performance of a flat-plate solar air heater (SAH). Solar air heaters are efficient, renewable systems that convert solar energy into heat. The paper builds on prior numerical research by fabricating a prototype SAH and conducting experiments to validate theoretical predictions. The SAH (1.83 m × 1.11 m × 0.2 m) was tested under varying conditions. Key parameters included a mass flow rate of 0.01–0.04 kg/s, an overall loss coefficient of 0–10 W/m2K, insulation thickness of 0.002–0.008 m, and absorber plate area of 0.5–2.5 m2. Results showed that mass flow rate and solar radiation significantly impact heat gain, peaking at 314.002 W for a mass flow rate of 0.0292 kg/s, while efficiency reached a maximum of 21.7%. The convective heat transfer coefficient also improved with increased mass flow rate, peaking at 12.51 W/m2K. An inverse relationship between heat gain and heat loss coefficient was observed, with optimal insulation thickness minimizing heat loss. The experimental results aligned with theoretical predictions, emphasizing the importance of optimizing mass flow rate and insulation thickness for better SAH performance.