Table of Contents
ISRN Renewable Energy
Volume 2014, Article ID 529280, 6 pages
Research Article

The Effect of PCM Capsule Material on the Thermal Energy Storage System Performance

1Department of Mechanical Engineering, Sri Venkateswara Institute of Technology, Anantapuram 515722, India
2Department of Mechanical Engineering, Sri Sivasubramaniya Nadar College of Engineering, Chennai 603110, India
3JNTU College of Engineering, Anantapuram 515722, India

Received 31 August 2013; Accepted 5 December 2013; Published 21 January 2014

Academic Editors: Z. Oktay and R. P. Saini

Copyright © 2014 R. Meenakshi Reddy et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Phase change material (PCM) based thermal energy storage (TES) systems are gaining increasing importance in recent years in order to reduce the gap between energy supply and demand in solar thermal applications. The present work investigates the effect of PCM capsule material on the performance of TES system during charging and discharging processes. The TES unit contains paraffin as PCM filled in spherical capsules and is integrated with flat plate solar collector. Water is used as sensible heat material as well as heat transfer fluid (HTF). The PCM capsules are of 68 mm diameter and are made using three different materials, namely, (i) high density polyethylene (HDPE), (ii) aluminum (Al), and (iii) mild steel (MS). The experimental investigation showed that the charging and recovery of stored energy are less affected by the spherical capsules material. The variables, like charging time and discharging quantity, are varied around 5% for the different capsule materials. Even though aluminum thermal conductivity is much higher than HDPE and mild steel, its influence on the performance of TES system is very low due to the very high internal heat resistance of PCM material stored in the spherical capsules.