Advancing thermal energy storage: Unravelling the optimal orientation of annular phase change material containers within the tank

This study investigates the efficiency of thermal energy storage (TES) systems employing phase change material (PCM) in tanks of different configurations. Six different distinct models of tanks are investigated numerically. The focus lies on analyzing temperature contours, liquid fraction contours, and specific enthalpy contours to understand the dynamic behavior of PCM during the phase change process. Particular attention is given to the placement of PCM containers about the inlet and outlet flow, ensuring optimal thermal interaction with the heat transfer fluid (HTF). The results indicate significant improvements in melting times compared to the baseline Model A, which has a cylindrical PCM container. Model B, incorporating annular PCM containers, achieves a notable reduction of 26.31 % in melting time, completing the melting process in 1680 s. With repositioned annular PCM containers at the tank's apex, Model C further enhances efficiency, achieving a 29.82 % reduction in melting time at 1600 s. Model D, featuring enhanced proximity between annular PCM containers, demonstrates a remarkable 31.57 % reduction, completing the melting process in 1560 s. Likewise, Model E, equipped with leftward inclined annular PCM containers, matches this reduction, achieving complete melting in 1560 s. Model F, incorporating a rightward inclination of annular containers, emerges as the most efficient, boasting a remarkable 33.33 % reduction in melting time, concluding the melting process in a mere 1520 s. These findings underscore the pivotal role of PCM container geometry, position, and inclination in optimizing heat transfer and PCM phase-change efficiency. The study provides valuable insights into designing and implementing PCM-based TES systems, offering a promising avenue for sustainable energy solutions.