NUMERICAL STUDY OF SOLIDIFICATION OF NANO-ENHANCED PHASE CHANGE MATERIAL IN A SPHERICAL THERMAL BATTERY
In this paper, solidification of erythritol phase change material in a spherical reservoir is studied to describe the effects of nano-enhancement on heat storage and heat transfer rate for application to waste heat recovery in the temperature range of 100°C - 140°C. The nanoparticles presence modifies base fluid thermophysical properties which in turn changes the heat transfer and the phase change pattern. The detailed analysis of the nanoparticles on the various thermophysical properties is performed. Thereafter, a macroscopic model for solidification of erythritol is presented in which the complete set of equivalent governing equations (mass, momentum, energy) are solved using a pressure-based finite volume method within a one-domain continuum formulation using an in-house code. The solidification behaviour of PCM (Phase Change Material) and NEPCM (Nano-Enhanced Phase Change Material) is compared. The influence of the nano-enhancement on the coupled heat transfer and fluid flow behaviour is described. Further, an empirical relationship involving non-dimensional numbers is proposed to assess the thermal performance, which can be used to design erythritol based TES with nano-enhancement.