Performance analysis of a mini solar air heater using locally available absorber materials

Solar air heaters are among the simplest and most cost-effective solar thermal devices used for space heating, crop drying, and low-temperature industrial applications. Their performance is strongly influenced by the design of the absorber plate and the thermal properties of materials used. In many developing regions, the adoption of solar air heaters is limited by high material costs and dependence on commercially manufactured absorber components. This research presents a performance analysis of a mini solar air heater fabricated using locally available absorber materials, aiming to evaluate their thermal effectiveness, feasibility, and suitability for small-scale applications. The experimental setup consists of a compact, single-pass solar air heater with interchangeable absorber plates fabricated from mild steel sheet, aluminium sheet, and black-painted corrugated metal commonly available in local markets. The system performance is assessed under natural outdoor conditions by measuring inlet and outlet air temperatures, solar radiation intensity, mass flow rate of air, and ambient temperature. Thermal efficiency, temperature rise, and useful heat gain are calculated for each absorber material using standard heat transfer relations. The comparative analysis highlights the influence of material thermal conductivity, surface roughness, and absorptivity on overall system performance. Results indicate that locally sourced absorber materials can achieve satisfactory thermal efficiencies when properly treated and integrated into the solar air heater design. The findings demonstrate that cost-effective alternatives to conventional absorber plates can significantly enhance the accessibility of solar thermal technology without compromising performance. This research contributes to the promotion of sustainable energy solutions by encouraging the use of locally available resources, reducing fabrication costs, and supporting decentralized renewable energy deployment. The outcomes are particularly relevant for rural and semi-urban regions where affordability, simplicity, and ease of maintenance are critical factors for the successful adoption of solar air heating systems.