Thermal energy storage with PCMs: A comprehensive study of horizontal shell and multi-tube systems with finned design

Abstract

Due to its unique qualities and advantages, phase change materials (PCMs) are crucial for thermal energy storage in various applications. The poor conductivity of PCMs is known to cause delayed charging and discharging rates. So, various techniques were proposed by the researchers to improve the thermal performance of PCM systems. To address this challenge, a comprehensive numerical research was presented on a horizontally oriented finned shell-and-tube type of PCM storage. The investigation was divided into four parts: (i) effects of the quantity and arrangement of heat transfer fluid (HTF) tubes; (ii) effects of the quantity and arrangement of fins; (iii) effects of the length of fins; and (iv) effects of various configurations of the finned shell-and-tube PCM storage. The outcomes depicted that due to buoyancy impact and horizontal location, the upper portion of the PCM storage melted more quickly than the lower portion. Also, it was found that, concerning the effect of the HTF arrangement (lacking fins) on the PCM melting process, with a 67.1 % improvement factor over a base model without fins, a double vertical array of HTF tubes produced the quickest melting time. Moreover, regarding evaluating the impact of the fins arrangement (one HTF tube), with a 39 % improvement factor, the diamond arrangement of fins was shown to be the best configuration for speeding up melting. For the complete melting process (LF = 1), the most significant improvement factor of 53.2 was noted for a fin length of 5.1 mm. Finally, the obtained numerical outcomes depicted that the complete melting time (at LF = 1) was reduced by 69.14 % in the model with a double vertical array of HTF tubes and a double vertical arrangement of fins, making it the ideal layout for the finned shell-and-tube PCM storage system.