Effect of fin length on solidification rate in a latent heat energy storage system

Abstract

ABSTRACT The main problem encountered in Latent Heat Energy Storage (LHES) Systems is to find and apply the methods increasing phase change rate. The use of finned heat exchange surfaces seems to be an attractive way among several methods handling that problem. The aim of this work is to ascertain the usefulness of finned surfaces in a LHES unit including a definite amount of Phase Change Material (PCM) and to determine the effect of fin length on phase change rate. For that purpose, solidification of liquid water whose initial temperature was at the fusion value was analysed for three different types of heat exchange surfaces; namely without fin, with a short fin and with a long fin. Experiments were carried out for three different average base temperatures of the finned surface. During the experiments slides were taken from the frontal face of the solidification unit at predetermined time intervals. The images were projected on a flat surface in full scale and the areas defined by solidification contours were evaluated with a digital planimeter. Solidification quantity vs. time curves obtained for three different types of heat exchange surfaces are compared. It is concluded that long fins are more effective in enhancing solidification rate.