Study of ionic water/graphene nanofluids in solar panels under the effects of thermal radiation and slip conditions using experimental data

Abstract

The combination of the extensive surface area and thermal conductivity of graphene oxide (GO) with the thermal stability and low volatility of ionic liquid (IL) enhances thermal energy efficiency in solar collectors. This study theoretically examined the flow characteristics of various nanofluids in a solar collector, specifically ionic liquid/GO, a mixture of 75% ionic liquid and 25% water (H${}_2$O)/GO, a 50% ionic liquid and 50% water/GO blend, and water/GO. To accurately assess the effects of buoyancy, solar radiation, nanoparticle absorption, and the overall thermal energy transfer from the boundary to the collector, this study incorporates nonlinear free convection, nonlinear thermal radiation, heat absorption, and slip and jump phenomena under convective conditions. The mathematical model was developed using non-similarity variables, and the results were obtained using the Garlakin weighted residual method (GWRM). This study demonstrates that an increase in the nonlinear free convective parameter, nonlinear thermal radiation, and heat absorption enhances the thermal energy of the nanofluid within the collector. The pure ionic liquid combined with graphene oxide (IL/GO) nanofluid demonstrated a thermal energy efficiency that exceeded that of water by 36.8%, which quantitatively corroborated the experimental result of 37.4%. This indicates that increased IL/GO nanofluid concentrations are optimal for high-intensity solar applications, whereas water is preferable for moderate solar conditions to prevent overheating.