Thermal Conductivity Enhancement of Ag/MCM-41 Hybrid Nanofluid for Solar Photothermal Applications

Abstract We studied thermal properties of silver nanoparticle and mesoporous silica (MCM-41) nanofluid in aqueous solution and evaluates its potential for enhancing solar thermal system performance. FE-SEM, EDS, and Zeta-potential confirmed the successful preparation of the hybrid nanofluid. Experimental conditions were optimized via Box-Behnken design and thermal conductivities were experimentally measured using a KD2 Pro device (from 30°C to 50°C). Under optimal conditions (79.11 ppm Ag, 746.08 ppm MCM-41 at 50°C), results demonstrated a 13.44% improvement compared to water. Further theoretical calculations and TRNSYS simulations assessed the nanofluid's performance in a solar collector model. Data suggest an increase of 1.26% and 6.05% (vs. water) in the solar collector's thermal efficiency and the convection heat transfer coefficient, respectively. Conventional fluids are less satisfactory with low thermal conductivity and instability at high temperatures. Here, Ag/MCM-41 hybrid nanofluid is a promising medium for improving heat transfer in solar thermal systems and potentially other industrial applications.