Improve the performance of solar thermal collectors by varying the concentration and nanoparticles diameter of silicon dioxide

Abstract The influence of different concentrations and nanoparticles’ diameter silicon dioxide nanoparticles on the Nusselt number enhancement ratio friction factor for solar thermal collector (STC) was examined numerically. CFD model designed to show flow water/SiO 2 pure water inside pipe performance STC. Different SiO are used ( ϕ = 1–4%) with several nanoparticle diameters (dp 20–50 nm). under Reynolds numbers ranging from 5,000 30,000. average Nu avg improved by increasing both fluids. increases increase in concentration nanoparticles. 5%) 20 nm) has highest number. enhances 25% nanofluid at Re 15% It is noted that skin decreases Water/SiO a higher than water. 31% lowest using as working fluid change 1%) 4%) 42% decrease led an across all numbers. size provides provide This investigation confirmed AL O 3 5% (diameter significant heat transfer improve efficiency