Phase change characteristic study of spherical PCMs in solar energy storage

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.solener.2009.02.006 Byline: M. Veerappan (a), S. Kalaiselvam (a), S. Iniyan (a), Ranko Goic (b) Keywords: Phase change material; Thermal energy storage; Analytical model; Solidification; Melting Abstract: This paper investigates the phase change behavior of 65mol% capric acid and 35mol% lauric acid, calcium chloride hexahydrate, n-octadecane, n-hexadecane, and n-eicosane inside spherical enclosures to identify a suitable heat storage material. Analytical models are developed for solidification and melting of sphere with conduction, natural convection, and heat generation. Both the models are validated with previous experimental studies. Good agreement was found between the analytical predictions and experimental study and the deviations were lesser than 20%. Heat flux release at the wall, cumulative energy release to the external fluid, are revealed for the best PCM. The influence of the size of encapsulation, initial temperature of the PCM, the external fluid temperature on solidified and molten mass fraction, and the total phase change time are also investigated. Author Affiliation: (a) Refrigeration and Air Conditioning Division, Department of Mechanical Engineering, Anna University, Chennai, Tamil Nadu 600025, India (b) Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture, University of Split, Croatia Article History: Received 4 May 2007; Revised 14 February 2009; Accepted 19 February 2009 Article Note: (miscellaneous) Communicated by: Associate editor Halime Paksoy