Thermal Performance of Paraffin Enhanced With Fe₂O₃ and CuO Microparticles in Solar Air Heaters

Abstract

Solar air heaters (SAHs) are highly efficient, environmentally friendly, and cost effective devices for applications such as solar drying and space heating. However, the intermittent nature of solar energy significantly reduces the thermal efficiency of SAHs. Energy storage method is used to increase the thermal efficiency and operating hours of SAHs. In this study, the effect of microparticle doped paraffin, one of the phase change materials (PCMs) used for latent heat storage, on the thermal performance of SAHs was investigated experimentally. The thermal properties of paraffin doped with CuO and Fe₂O₃ microparticles and their behavior in energy storage processes were compared and analyzed. The PCM integrated collectors exhibited an average outlet temperature difference of up to 10°C compared to the flat collector, with maximum outlet temperatures reaching 60°C during peak solar radiation periods. DSC analysis revealed latent heat values of 107.2 and 122.7 J/g for CuO and Fe₂O₃ doped PCMs, respectively, indicating improved thermal energy storage compared to pure paraffin. Particularly, the Fe₂O₃ microparticle doped material excelled with faster energy storage and higher temperature differences. In contrast, the CuO microparticle doped material released the stored energy in a more controlled manner and over a longer period. The results indicate that both materials can be used to enhance energy efficiency and operating duration in solar energy applications.