Thermal and Structural Analysis of Hybrid Nanofluids in Solar Thermal Collectors: A Numerical Study

Abstract

Solar thermal collectors can be significantly improved by the integration of advanced working fluids with higher thermal conductivity. This study presents a numerical investigation of hybrid nanofluids (Al₂O₃–Cu/water) for enhancing thermal efficiency in flat plate solar collectors under Algerian climatic conditions. Using computational fluid dynamics (CFD), the energy and momentum equations were solved with a two-phase mixture model to capture nanoparticle-fluid interactions. Parametric variations in nanoparticle volume fraction (0–5%) and flow rate were analyzed. Results indicated that a 4% hybrid nanoparticle concentration increased thermal efficiency by 21% compared to water-based collectors. Temperature profiles showed enhanced uniformity across the absorber plate, reducing localized overheating. Entropy generation analysis confirmed reduced irreversibility with optimized flow conditions. Furthermore, exergy analysis revealed improved collector performance at peak solar radiation levels, particularly in southern Algeria. The study highlights the potential of hybrid nanofluids as advanced heat transfer media for solar applications and provides design insights for sustainable energy systems in arid regions.