An experimental study for a single-pass solar air heater integrated with artificial roughness

Abstract

The utilization of solar air heaters are significant due to its capacity to diminish the reliance on fossil fuel-based power usage, hence mitigating pollution and conserving energy. The thermal-performance of a solar heater was analyzed using experimental simulations. Different types of artificial roughness, such as delta-winglet-vortex generators, ribs, or a combination of ribs and delta-winglet, were tested in a single-pass solar air heater. The objective of this study is to identify the optimal design that maximizes the thermal efficiency of a solar air heater. The relative roughness height-ratio remains constant at 0.6, although the pitch ratio is fixed at 10 and various attack angles are used. The experimental investigation was conducted within a range of Reynolds numbers (5000–14000). The usual levels of irradiance varied as 330 W/m2 - 850 W/m2. Based on the results, the average bulk temperature of the roughened solar air heater was 37% greater than that of a smooth SAH under peak sun irradiation. The inclined ribs at a 60° angle exhibited superior thermal efficiency compared to the other instances. These ribs covered a greater surface area and greatly enhanced the convective heat-transfer rate.