A comprehensive assessment of temperature difference and natural convection on phase transition in different latent heat storage systems accompanied by porous media

Abstract

Abstract With the constant increasing demand for energy and the challenges arising from the growing population, securing a reliable energy supply seems critical. Latent energy storage is introduced as one of the most efficient solutions to harness the renewable and waste energy and secure a constant supply. The phase change material (PCM) in this type of energy storage suffers from low responsiveness, slowing down the industrialization of latent storage. This study proposed different conventional PCM-based storage units to numerically analyze the most influential determinant in each system during the melting evolution. The working fluid temperature, natural convection and porous media at different porosities are the factors selected for comparison between four configurations. The temperature of working fluid is of similar significance to three types of units as an enhancement of 22% has been obtained by 5 degrees increase in inlet temperature, while the pipe model has benefited almost 26% improvement under the same condition. Triplex tube heat exchanger (TTHX) in all scenarios outperforms other units since the heat transfer area for this type is greater that that of its counterparts. Natural convection phenomenon is most effective in the pipe model as its absence decelerate the melting rate by 236%. Porous media integration produced, by average, 93% faster systems thanks to its extra heat transfer surface, although it suppressed the gravitational movement.