Metal foam reinforced phase change material energy storage device: A collaborative optimization strategy for porosity and container shape

Abstract

Latent heat thermal energy storage (LHTES) is often employed in solar energy storage systems to improve efficiency. This method uses phase change materials (PCM) as heat storage medium, often augmented with metal foam to optimize heat transfer. In this paper, we introduce a novel approach of altering the container shape to enhance the heat storage effectiveness. LHTES tank with different coning coefficients (C) is designed by reducing the hard-to-melt bottom region. Based on the finite volume, volume averaging, and enthalpy porosity method, the transformation process of a simplified two-dimensional model of the LHTES tank is numerically simulated. Analysis focuses on the evolution of liquid-solid interface, liquid fraction, temperature field, and heat storage performance. The results indicate that the bottom region area enhances the heat storage performance when C < 0.375, whereas for C ≥ 0.375, it hinders heat transfer. When the porosity is 0.93, the newly deformed LHTES tank demonstrates a reduction of up to 6.2% in melting time compared with the basic model. Additionally, it achieves 98% of the basic thermal energy storage. Furthermore, metal foams with varying porosity are analyzed, and a cooperative optimization matching strategy between porosity and shape is obtained. By reducing the porosity to 0.87, the melting time can achieve a 61% reduction at C = 0.125. This study is expected to provide new insights and references for optimizing the design of LHTES devices.