A Review on Thermal Conductivity Enhancement Techniques of PCM- Based Heat Exchanger

Abstract

Thermal energy storage as a latent heat is one of the most popular types of thermal energy storage. However, most phase change materials (PCMs) used in thermal storages suffered from low thermal conductivity. In this paper, the previous experimental and theoretical research studies on latent heat thermal energy storage (LHTES) with different operating and design parameters are reviewed, concentrating on techniques that be used of non-moving extended surfaces that have high conductivity. Both melting and freezing of (PCMs) within a variety of thermal energy storage container geometries and other various operating and design parameters such as, mass flow rate, inlet temperature of HTF and its direction, and orientation of PCM- heat exchangers were reported. The influence of all the above mentioned parameters are discussed very briefly, and proposed some recommendations. It was found that the orientation and thickness of the fins have insignificant effect on the performance of the storage system, compared with those caused by the number of fins (or fin-pitch) and fin length. Geometric parameters of fins also play an important role in the enhancement of heat transfer and thus the performance of PCM-heat exchangers.