Synthesis and characterization of Ag and Al doped ZnO dispersed nanofluids for heat transfer applications

Abstract

In this work, Ag and Al co-doped ZnO nanoparticles have been prepared through chemical synthesis route using zinc acetate, silver nitrate and aluminium nitrate. The synthesized nanoparticles are characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The nanofluids are prepared by dispersing 1 wt% of Al and Ag doped ZnO nanoparticles in ethylene glycol (EG)-water (W) mixture. The effect of base fluid on the thermal conductivity enhancement of the nanofluids has been studied by employing three different EG + Water mixtures namely, 25% EG-75% Water, 50% EG-50% Water and 75% EG-25% Water as base fluids. The nanoparticles are homogeneously dispersed in base fluids by using combined magnetic stirring and ultrasonication. The thermal conductivity of the nanofluids are measured through transient hot-wire technique. It is observed that the addition of small amount of Al and Ag doped ZnO nanoparticles to the ethylene glycol-water mixture increases the thermal conductivity of the base fluid. The 50% EG-50 Water mixture showed highest thermal conductivity enhancement of 37% compared to other base fluids when 1% Al and Ag doped ZnO nanoparticles are dispersed.