Ultrasonication assisted co-dispersion of nanostructured magnesium-lined paraffin wax and magnesium oxide in a heat transfer fluid for energy related applications

Magnesium-lined paraffin wax nanoparticles were prepared through probe ultrasonication, utilization of Tween 80 as surfactant and ionic interactions. These were co-dispersed with nanostructured magnesium oxide (0.6-2 vol%) in aqueous propylene glycol solution to obtain hybrid nanofluids. Magnesium-lined paraffin wax present in hybrid nanofluids underwent solid-liquid/liquid-solid transition between 45 degrees C and 62 degrees C during which thermal energy was absorbed/released, thereby increasing hybrid nanofluids' specific heat. The presence of magnesium oxide contributed to thermal conductivity enhancement of hybrid nanofluids, with a maximum of 20% for the one containing 2 vol% nanostructured magnesium oxide, attributable predominantly to the aggregation of primary nanoparticles as flower-like structure. Our data indicates augmentation of overall heat transfer coefficient with the utilization of hybrid nanofluid. (C) 2018 Elsevier B.V. All rights reserved.