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

Abstract

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 characteristics 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° 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. • Non-uniform angled fins are designed for improving energy storage. • A 69.59% reduction in full melting time is obtained compared with uniform straight finned tube. • Unbalance of thermophysical characteristics are effectively reduced by non-uniform design. • Non-uniform angled fins achieved heat flux improvement of TES unit as large as 29.19%.