Latent thermal energy storage system using phase change material in corrugated enclosures

Latent thermal energy storage (TES) systems rely on the use of phase change materials (PCMs) to store a significant amount of thermal energy. Current systems consist of small surface-to-volume ratio containers or enclosures that exhibit poor transient thermal performance. There is a need to enhance heat transfer in TES system with the goal of reducing charging and discharging times while maximizing surface-to-volume ratio. The aim of this study was to experimentally investigate the effectiveness of a newly designed TES system with high surface-to-volume ratio and high aspect ratio. Several parameters including Reynolds number, Stefan number, and heat transfer fluid (HTF) flow direction were considered and are presented in this paper. The TES consists of sealed corrugated copper panels containing octadecane arranged in a vertical configuration to promote a self-induced internal natural convection mechanism. Results show significant enhancement in charging and discharging rates by as much as 9 times when compared to concentric systems due to the high surface-to-volume ratio of the PCM panels used in the study. Buoyancy effects, observed at high Stefan numbers, were significant during the charging (melting) process and greatly influenced the temperature profiles along each vertical channel. A comparison of the effectiveness of the new TES device with other conventional devices found in the literature indicates that the devised TES performs better both in terms of thermal response time and heat transfer effectiveness. (C) 2012 Elsevier Ltd. All rights reserved.