Effects of SiO2 Nanoparticle Sizes and Concentrations on Enhancing Heat Transfer in Concentrated Solar Collectors: A CFD Simulation

This study quantitatively examines the influence of SiO2 nanoparticle concentration and dimensions on the thermal efficiency of a Concentrated Photovoltaic Thermal (CPVT) collector. Computational Fluid Dynamics (CFD) simulations employed water-SiO2 nanofluid with concentrations of 1-4% and nanoparticle sizes of 20-50 nm as the cooling medium in mini-channels beneath photovoltaic cells at Reynolds numbers between 2000 and 18000. The results indicated that elevating the nanoparticle concentration to 4% augmented the Nusselt number by 12.5% relative to pure water, but diminishing the particle size to 20 nm produced an extra 8% enhancement. The peak decrease in photovoltaic surface temperature was 15.2°C, attained at a 4% concentration and a nanoparticle size of 20 nm. Furthermore, the heat transfer coefficient rose by 18%, while thermal resistance diminished by 21%. These modifications markedly enhanced the thermal dissipation from the PV surface, which is pivotal in augmenting the electrical efficiency of the CPVT collector. The findings indicate that employing SiO2 nanofluid as a cooling medium effectively improves the thermal and electrical performance of CPVT systems.