Improving Solar Air Collector Performance With Glass Balls and Metal Fibers

ABSTRACT This study deals with optimizing solar collector performance, using porous media of glass spheres and metal fibers to compare the effect of each on thermal performance. The research problem stems from the need to improve heat absorption and increase the efficiency of solar energy conversion, given the environmental challenges and high costs of conventional energy. The study was carried out practically through the manufacture and installation of a pneumatic solar collector on the roof of the building of the Renewable Energies Research Unit at the Hawija Technical Institute, where the performance of the two systems was measured using precision instruments. The results showed that the metal fibers absorbed more heat during peak periods; the power gain reached 200 W compared to 190 W when using glass balls, but they lost heat quickly after that. In contrast, glass spheres retained heat for longer periods, resulting in a higher thermal efficiency of 57% compared to 52% for metal fibers. These results indicate that the performance of the solar collector was better when using glass balls due to their ability to store heat for longer periods and reduce energy loss, making them a more efficient and sustainable option in solar heating and ventilation systems. The novelty of this study lies in its direct experimental comparison between two distinct types of porous media—glass balls and metal fibers—under identical conditions, which has not been previously explored in the literature. This comparison offers fresh viewpoints about their relative effectiveness in thermal storage and heat transfer within solar air collectors.