Thermal assessment on solid-liquid energy storage tube packed with non-uniform angled fins

The solid-liquid phase change energy storage system promoted the efficient and sustainable utilization of dispersive and intermittent renewable energy. Low energy storage rate and unbalanced thermophysical char-acteristics existed in the vertical shell-and-tube heat storage tubes. To improve thermal properties and melting uniformity, this paper proposed a non-uniform angled fin type considering the optimization by the non-uniform arrangement and angled fins with small angles. A visual experimental platform was designed and built, and the reliability of the numerical model was verified by the experimental results. Numerical simulations of a single shell-and-tube heat storage tube regarding maximizing phase change rate were carried out. The development of the phase change interface and transient temperature field during the charging process of the non-uniform angled fins with downward 10 degrees were obtained. Results showed that, compared with the uniform straight fin tube, the non-uniform angled fin can effectively promote the melting process of the whole fin tube, especially in the bottom area, leading to a 69.59% reduction in complete melting time. This provided a reference for the performance optimization of the shell-and-tube finned phase change heat storage tube.