MgO and ZnO nanofluids passive cooling effects on the electricity production of photovoltaic panels: a comparative study

Overheating of solar panels stands as a pivotal factor that impacts their conversion efficiency. Therefore, implementing cooling for solar panels is a key strategy to enhance the electrical output; due to regulating their thermal properties. This study is set out to examine, experimentally, the back-passive cooling impact of MgO and ZnO water-based nanofluids at volume concentrations of 0.01%, 0.03%, and 0.05% on the thermal and electrical characteristics of polycrystalline silicon solar panels, compared with not cooled and water-cooled panels at the same time and under the same weather conditions. The system design is cost-effective and facilitates the direct contact between the cooling fluids and the photovoltaic system. The experimental results demonstrate that the application of MgO nanofluid introduces more improvement compared to the ZnO nanofluid and conventional water cooling. The electrical efficiency enhancement attains its maximum at a volume concentration of 0.05% with 20.90% and 21.65% for MgO and ZnO nanofluids, respectively, over the non-cooled panel. Simultaneously, at this concentration, the temperature reduction achieved by MgO nanofluid is 20.72%, surpassing the 15.80% reduction achieved by the ZnO nanofluid in comparison with the reference panel.