Performance Evaluation of CeO₂/Water Nanofluid in Flat Plate Solar Water Heating System: Experimental Analysis and Comparative Study

Abstract

The performance of solar water heating systems depends significantly on the collector design, working fluid, and stratification management within the storage tank. This study investigates the thermal performance of a forced-circulation flat plate solar water heating system utilizing CeO₂/water nanofluid as the working medium. The experimental setup was designed and installed in Bhopal, India, and performance was evaluated at varying nanofluid concentrations (0.01%, 0.05%, and 0.1%) and flow rates (1–3 L/min). Comparative analysis with conventional Al₂O₃/water nanofluid was also performed to assess the heat transfer augmentation potential of cerium oxide nanoparticles. Results revealed that CeO₂/water nanofluid achieved a maximum efficiency of 81.2% at 0.05% concentration and 2 L/min flow rate. Efficiency increased with flow rate up to 2 L/min due to improved convective heat transfer and decreased at higher flow rates due to reduced residence time. The outlet fluid temperature reached a peak of 78.5 °C, indicating strong thermal stratification and effective heat exchange within the collector. The study further supports that CeO₂ nanofluids provide higher thermal conductivity and stability than Al₂O₃, making them promising candidates for next-generation solar thermal applications.