Numerical research on the solidification heat transfer characteristics of ice thermal storage device based on a compact multichannel flat tube-closed rectangular fin heat exchanger

In this study, a compact ice thermal storage device that combines multichannel flat tube and closed rectangular fins is designed to improve solidification performance. To analyze the heat transfer characteristics and visualize the ice formation process, a numerical model was formulated and solved using enthalpyporosity method. The temperature distribution, liquid fraction, and ice front evolution were studied during solidification process. The effect of heat transfer fluid on the performance of storage device at different inlet temperatures and flow rates was numerically investigated. Results show that when the inlet temperature was reduced from -3 degrees C to -6 degrees C, the ice packing factor increased by 32.2% and the storage power forms a linear relationship with the inlet temperature. When the flow rate was increased from 0.1 m(3)/h to 0.2 m(3)/h, the ice packing factor increased by 8.7% but the effect of flow rate was less obvious than the inlet temperature. Furthermore, the heat transfer characteristics of closed rectangular fins were compared with traditional longitudinal fins. We found that the former can achieve more uniform temperature distribution and a higher ice formation rate. The average solidification enhancement ratios of the both are 2.28 and 2.08, respectively, the former being 9.6% higher than the latter. (C) 2021 Elsevier Ltd. All rights reserved.