An Experimental Study of Inward Solidification of Nano-Enhanced Phase Change Materials (NePCM) Inside a Spherical Capsule

Nano-enhanced phase change materials (PCM), referred to as NePCM, have been proposed by doping highly thermally-conductive nanofillers into matrix PCM to prepare composites that have enhanced thermal conductivity. The classical problem of inward solidification of PCM inside a spherical capsule, with applications to thermal energy storage, was revisited in the presence of nanofillers. In this work, the model NePCM samples were prepared with 1-tetradecanol (C₁₄H₃₀O) possessing a nominal melting point of 37 °C as the matrix PCM. Graphite nanoplatelets (GNPs) were synthesized and utilized as the nanofillers at loadings up to 1% by weight. The transient phase change and heat transfer during solidification were characterized by means of an indirect method that is based on the knowledge of transient volume shrinkage of the PCM. The experimental results showed that the total solidification time becomes shorter with increasing the loading of GNPs, in accordance to the increased effective thermal conductivity of the NePCM samples.