12. Thermal Performance Enhancement of Flat-Plate Solar Collector Using CeO₂–Water Nanofluid

In the present study, the effects on the thermal performance of nanofluid in flat-plate solar collector are studied experimentally. The thermophysical properties (thermal conductivity, viscosity, density, and specific heat) of CeO₂–water nanofluid measured with a wide range of volume concentrations (0.25–2.0%) using 30 nm particle size. Maximum enhancement in thermal conductivity is observed up to 41.7% at 1.5% volume fraction of nanofluid at an 80 °C temperature in comparison with the base fluid. Viscosity decreases with increasing the temperature but increases with a particle volume concentration of nanofluid at a particular temperature. The experimental setup fabricated for the study of heat collection using a flat plate. The mass flow rate of nanofluids was adjusted (at a given volume concentration) for experimentation. The collector temperatures, ambient, and tap water temperatures, radiation, and wind speed were measured. Experimental results exhibit that the maximum collector efficiency is obtained up to 57.1% at an optimum concentration with a mass flow rate of 0.03 kg/s. The results show that the CeO₂–water nanofluid as working fluid improves the collector efficiency in comparison with water as a working fluid. This also has been observed that the thermal efficiency of collector increases with a decrease in the temperature reduced parameter.