Thermal energy storage system based on nanoparticle distribution optimisation for enhanced heat transfer

Abstract

As a new type of heat transport medium with high efficiency and high heat transfer performance, nanofluids can effectively improve the heat transfer performance of thermal systems. In this paper, a lattice Boltzmann method is employed to propose a novel thermal storage system with optimised nanoparticle distribution using spacer-separated nano-enhanced PCM with spacer arrangement. The thermal energy storage units are separated by thermal insulation and heated by means of thermally conductive fluid channels. The effects of Rayleigh number, volume fraction and layout pattern are investigated. It is shown that the larger the Rayleigh number is, the more intense the reaction of the heat storage system is; it is concluded that the strong convection phenomenon in the upper left side region is more than that in the lower left side, and the volume fraction in the lower left side can be reduced to enhance the efficiency of this heat transfer in order to achieve a faster melting rate. The various distributions studied in this paper all have the effect of accelerating the melting rate to varying degrees compared to Type 1. The present study shows that increasing the volume fraction of phase change material in the upper left side of the square cavity has a promoting effect on the melting rate when compared to the lower side, and the larger the difference between the two, the better the effect is.