Synthesis and characterization of cooling biodegradable nanofluids from non-edible oil for high voltage application.

Mineral oil has been serving well as a cooling and insulation oil in high voltage power equipment but with a setback when considering environmental friendliness whenever there is spillage due to its poor carbon profile. Several works have been done on the enhancement of dielectric properties of green alternative with different nanoparticles but little attention was placed on its cooling properties which is one of the major functions of the oil. Also, to prevent food competition, esters from a non-edible seed oil should be given more consideration. This work, therefore, investigates the cooling properties of synthesized insulating nanofluid using Neem oil ester as the base fluid together with (Insulating) SiO 2 and (semiconductive) WO 3 nanoparticles. The nanoparticles were characterized using FTIR and XRD to confirm their functional groups and crystallite size respectively. Transesterification of the oil was done using sodium methoxide and the nanofluid samples were prepared by dispersing the nanoparticles into the oil. The nanoparticles were varied from 0.2 wt% to 1 wt%. The pour point, flash point and viscosity were measured according to ASTM standards. An increase in the pour point, flash point and viscosity were observed at every loading of the nanoparticle. The nanofluid with dispersed SiO 2 nanoparticles were observed to possess superior properties as a cooling liquid in high voltage power equipment when compared with the fluid with WO 3 nanoparticles because of its low viscosity, low pour point and good flash point. After the ageing, the synthesized fluids still retained their properties which is better than the mineral oil. • The influence of SiO 2 and WO 3 nanoparticles on the physical properties of the Neem oil ester was examined. • The two nanoparticles enhance the Flash point of the Neem oil ester. • An increase in the pour point of the Neem oil ester was observed through addition of the two nanoparticles. • A slight increase in the viscosity of Neem oil ester was observed after the addition of the particles. • After ageing of the nanofluids, the viscosity of the nanofluid was found better than the viscosity of the aged mineral oil. [ABSTRACT FROM AUTHOR]