Numerical Study of the Effect of Coolant Type on Photovoltaic Temperature Distribution

Environmentally friendly and sustainable alternative energy sources have become a key focus in reducing dependence on fossil fuels. One of the rapidly advancing technologies in the field of renewable energy is photovoltaics. Photovoltaic systems directly convert solar radiation or light energy into electrical energy based on the photovoltaic effect, which refers to the emergence of an electric voltage due to the contact between two electrodes connected within a solid or liquid medium when exposed to light energy. This technology offers advantages such as clean operation, zero emissions, and relatively low maintenance, making it suitable for a wide range of geographical and climatic conditions. However, an increase in cell temperature above 25° C-commonly referred to as the Standard Test Condition (STC)-leads to an efficiency reduction of approximately $\mathbf{0. 5 \% - 0. 6 \%}$ for every $\mathbf{1}^{\circ} \mathbf{C}$ rise. To maintain surface temperature uniformity, a CFD simulation of a cooling system using a channel box on the rear side of the photovoltaic panel was conducted. The coolant flow, consisting of water, $\text{Al}_{2} \mathrm{O}_{3}$ nanofluid, and $\text{Fe}_{2} \mathrm{O}_{3}$ nanofluid, was characterized as laminar, with Reynolds numbers of 966.23, 974.76, and 991.25, respectively. The spatial temperature distribution indicated that under $1000 ~\mathrm{W} / \mathrm{m}^{2}$ irradiance, water achieved the best performance with the lowest temperature deviation of 3.013. Under 800 and $900 ~\mathrm{W} / \mathrm{m}^{2}$ conditions, the $\text{Al}_{2} \mathrm{O}_{3}$ nanofluid demonstrated superior uniformity in temperature distribution, with deviations of 2.563 and 2.771, respectively.