Investigation of Heat Transfer Characteristics of Al2O3-Embedded Magnesium Nitrate Hexahydrate-Based Nanocomposites for Thermal Energy Storage

Abstract

Phase change materials (PCMs) have been widely investigated as latent heat energy storage medium for effective thermal management. Presently, PCM nanocomposites have been prepared by dispersing aluminum dioxide (Al2O3) nanoparticles (NPs), which act as thermally conductive nanofillers, in molten magnesium nitrate hexahydrate (Mg(NO3)2·6H2O), an inorganic salt hydrate. Al2O3 NPs with mass fractions of 0.5, 1.0 and 1.5 wt% have been dispersed in liquid PCM to obtain PCM nanocomposites, which are used to study the heat transfer properties. The morphology of the Al2O3 NPs, PCM and PCM nanocomposites has been studied by scanning electron microscopy (SEM). Fourier-transform infrared spectroscopy (FTIR) analysis was carried out to investigate the interaction between Al2O3 and PCM in PCM nanocomposite. The melting (charging) and solidification (discharging) characteristics of the PCM nanocomposites have been recorded and analyzed. The experimental results clearly showed that the rate of melting and solidification of PCM nanocomposite increases by 15% and 38%, respectively, with an increase in the mass fraction (1.5 wt%) of nanofillers as compared to the pristine PCM. The observed reduction in heat release time confirmed the effective enhancement of thermal conductivity in Al2O3-PCM nanocomposite samples as compared to the pristine PCM. The prepared PCM nanocomposites displayed superior heat transfer capability, making it a potential candidate for thermal energy storage.