Thermal Efficiency Enhancement and Entropy Generation Reduction in Solar-powered Water Pumping Systems Using Oldroyd-B Hybrid Nanofluids in Nigeria

Abstract

With the growing demand for sustainable and efficient energy solutions, optimizing solar water pumping (SWP) systems has become a priority. This study evaluates the thermal performance of a hybrid nanofluid (HNF) composed of AA7075–Ti–6Al–4V/ethylene glycol and compares it with a mono-nanofluid (AA7075/EG) for cooling applications. Considering the environmental impacts of conventional pumping systems, including high energy consumption and greenhouse gas emissions, the research investigates the heat transfer and flow characteristics of these advanced fluids. The mathematical model incorporates thermal radiation, heat generation, viscous dissipation, porous media effects, and viscoelastic properties, formulated as coupled non-linear partial differential equations. Numerical solutions are obtained using the fourth-order Runge-Kutta (RK4) method, yielding precise profiles of dimensionless velocity, temperature, and entropy generation. Results show that the hybrid nanofluid outperforms the mono-nanofluid in thermal conductivity and heat transport. Sensitivity analysis highlights the trade-offs between cooling efficiency and system irreversibility. By optimizing key parameters, including nanoparticle volume fraction, suction/injection rates, and Deborah numbers, this study provides a framework for designing more efficient, durable SWP systems, enhancing water and energy security in remote regions.