Development and Construction of a Multipurpose Mini-Solar Water Heater for Sustainable Development Goals

ABSTRACT Solar energy offers a promising renewable alternative to conventional water heating systems reliant on fossil fuels. This study aimed to design and fabricate an optimized mini-solar water heater to tap into abundant solar resources while addressing several sustainable development goals. A thorough literature review was conducted on solar water heating systems, with a focus on mini-scale technologies. Key factors such as sizing calculations, material selection, fabrication processes, performance evaluation parameters, and efficiency enhancement techniques were analyzed. Nigeria’s solar irradiance profile and domestic hot water demand were also considered. The designed system comprised a 0.76m2 flat-plate solar collector, 20L insulated storage tank, and supporting frame. Materials like aluminum, copper, stainless steel and fiberglass were selected based on specifications and cost. Detailed dimensional calculations were performed to determine component sizes. Fabrication involved arc welding, lathing and adhesive bonding. Performance was tested over six days under varying weather conditions. System outlet temperature, efficiency, and irradiance levels were recorded hourly. Results showed the heater successfully heated water to a maximum of 79.3°C. Performance proved more favorable during dry season testing, achieving outlet temperatures up to 11°C higher than the wet season. Peak irradiance coincided with maximum outlet temperature and efficiency. The study demonstrated the technical feasibility of portable mini-solar water heating for off-grid use. Further enhancements to functionality, control, and data collection were recommended. The developed technology promotes universal clean energy access per SDG7 while facilitating climate action under SDG13 through avoided fossil fuel emissions. This research contributes to making renewable options economically viable and environmentally sustainable.