Simulation study on the effect of fins on the heat transfer performance of horizontal dual-inner-tube latent thermal energy storage heat exchangers

Abstract

Compared with the traditional horizontal double-tube heat exchangers, the horizontal dual-inner-tube latent thermal energy storage (LTES) heat exchangers can effectively shorten the melting time of the phase change materials (PCMs). This paper analyzed the liquid phase distribution, temperature field, melting rate and heat storage about finless horizontal dual-inner-tube latent thermal energy storage heat exchangers during the melting, and researched the effects of the fin position and number on melting progress and heat storage performance. The results showed that compared with the variation of fin number, the reasonable fin arrangement is better to improve heat transfer performance, and the heat transfer performance reaches to the optimal value when the single fin is placed at the bottom of the lower tube, which can shorten the melting time by 23.91% compared with the finless condition, but the increase of fin number on the basis of the optimal single fin arrangement only shortens the melting time by 1,2%. Additionally, it also obtained that the time of the high melting rate reduces by 9.14% when the fin is installed in the middle of the exchangers body, which weakens the effect of strengthening heat transfer. These results indicate that the less fins, if the arrangement is designed properly, can be as efficient as more fins in horizontal dual-inner-tube LTES heat exchangers.