Photovoltaic-Thermal Integrated with Shea Butter as Phase Change Material to Enhance Electrical Efficiency and Hot Water Production in Sub-Saharan Africa: Nigeria as Case Study

Sub-Saharan Africa receives the highest annual sunshine hours of any continent, which creates high temperatures for photovoltaic cells that need effective cooling solutions. The common use of paraffin wax in the literature is problematic, as it comes from fossil fuels, making it neither environmentally friendly nor sustainable. This research provides a comprehensive analysis of PV-T/PCM in sub-Saharan Africa, with a specific focus on climate conditions in Nigeria. It introduces shea butter as a new PCM for PVT applications, a subject that has not been previously examined. The PVT system was modelled numerically with shea butter as the PCM in TRNSYS for active cooling in photovoltaic (PV) systems. Shea butter's performance was compared to that of traditional paraffin wax, and the sensitivity of system design parameters was also analysed. Shea butter outperformed traditional paraffin wax by significantly reducing cell temperatures during peak sunlight hours, leading to improved electrical power output and efficiency (peak: 130.53 W versus 109.78 W for traditional PV) and (peak: 11.35% versus 9.10%), respectively. It also offers notable environmental benefits, being renewable, biodegradable, and associated with a lower carbon footprint. Economically, shea butter encourages income generation and empowerment for women in West Africa. Increasing water flow rates (0.5–2.5 LPM) effectively decreases the temperature, with an optimal flow rate of 2.0 LPM. The study also determined an ideal shea butter layer thickness of 0.04 m, balancing thermal capacity and heat transfer efficiency. Overall, shea butter has the advantage in timing for PV cooling; shea butter activates during the peak radiation hours, paraffin does not.