Preparation and thermophysical properties of nanoparticle-in-paraffin emulsion as phase change material

In this study, phase change material (PCM) embedded by nanoparticles was prepared by emulsifying alumina (Al2O3) nanoparticles in paraffin (n-octadecane) by means of a non-ionic surfactant. The formulated nanoparticle-in-paraffin emulsions contain the nanoparticles of 5 wt.% and 10 wt.%, respectively; their effective thermophysical properties, such as latent heat of fusion, density, dynamic viscosity, and thermal conductivity, were investigated experimentally. The experimentally measured density of the emulsions agrees excellently with that predicted based on the mixture theory. The measured thermal conductivity and dynamic viscosity for the nanoparticle-in-paraffin emulsions formulated show a nonlinear increase with the mass fraction of the nanoparticles compared with that for the pure paraffin, depending on the temperature.