Behavior of Nano-enhanced Phase Change Material in a Spherical Thermal Battery During Unrestricted Melting

Abstract

In this paper, unrestricted melting of erythritol phase change material (PCM) is studied in a spherical reservoir to describe sinking effects on heat storage and heat transfer rate with nano-enhancement. The unrestricted melting leads to strong stratified thermal zones in the reservoir, and further nanoparticles’ presence modifies base fluid thermophysical properties which in turn alter the heat transfer and the phase change patterns. A macroscopic one-domain continuum model for the unrestricted melting of erythritol is developed. The complete set of conservative governing equations is solved employing pressure poisson equation (PPE) with finite volume discretization method. The homogeneous modeling approach is used to predict thermophysical properties of the nano-enhanced phase change material (NEPCM). The developed model is validated with the experimental results available in the literature. The unrestricted melting behavior of PCM and NEPCM is compared. The influence of nano-enhancement on the coupled fluid flow and heat transfer behavior is described. Further, performance indicators of PCM/NEPCM-based thermal energy storage (TES) systems, like sensible energy and latent energy content, are delineated in both cases to explore its potential in designing erythritol-based TES systems with nano-enhancement, in the medium temperature range of 100–150 °C.