A numerical study on the effect of the number and arrangement of tubes on the melting performance of phase change material in a multi-tube latent thermal energy storage system

•Two-dimensional numerical simulations were conducted for melting process of phase change material.•The effect of number and arrangement of tubes was investigated with considering eight arrangement of tubes.•An increase in the number of tubes enhanced the melting rate in the initial stage and the energy density.•The tube arrangement affected the required melting time. This study numerically investigates the effect of the number and arrangement of tubes on the melting performance of a phase change material (PCM) in a multi-tube shell-and-tube latent heat thermal energy storage (LHTES) system. An enthalpy-porosity model was used to simulate the phase change process. Eight arrangements of tubes were examined. The melting characteristics, energy density, distributions of the liquid fraction and temperature, heat transfer rate, and melting time were analyzed. The melting performance and energy density were influenced by both the number and arrangement of tubes. An increase in the number of tubes enhanced the melting rate in the initial stage and the energy density. The tube arrangement affected the required melting time. Two vertically arranged tubes resulted in the lowest melting time, and eight tubes resulted in the highest energy density. A correlation is proposed to estimate the total melting time with respect to the number and arrangement of tubes in LHTES.