Numerical simulation on heat transfer enhancement of phase change thermal storage devices for low-middle temperature

Using Ba(OH)2·8H2O as phase change material (PCM) and water as heat transfer fluid (HTF), we numerically simulated annular finned-tube heat exchangers. In order to measure and analyze the impact of parameters in the heating/cooling process, temperature changes of different monitoring points, fin widths, and fin pitches as key parameters were considered and applied. The experimental results show that the heat exchange process can be divided into three stages within a certain time. The faster heat transfer rate is associated with the greater temperature difference between PCM and HTF. Furthermore, fins width and pitch affect dramatically the heat charging/discharging rate. The large fins width or small fins pitch is beneficial for extending the heat exchange surface, leading to improve heat transfer efficiency.