Heat Transfer Augmentation of Latent Heat Thermal Storage Systems Employing Extended Surfaces and Heat Pipes

Abstract

Latent heat thermal storage (LHTS) systems containing phase change materials (PCMs) have been increasingly appealing in recent years for use in thermal systems due to their high-latent heat storage capacity, small volume change, and nearly isothermal behavior during the melting and solidification processes. However, the low thermal conductivity of these materials is a limiting factor for their deployment. This drawback hinders the heat transfer rate between the PCM and heat source or sink resulting in slow charging and discharging of the thermal systems which are the main concern for many practical applications. In order to increase the heat transfer in LHTS systems, several augmentation techniques have been developed. These techniques are classified into three main groups including heat transfer enhancement methods, thermal conductivity enhancement methods, and combination of different enhancement methods. This chapter briefly introduces the different heat transfer enhancement techniques employed in LHTS systems and then explains the two techniques of fins and heat pipes in more detail. This includes different fin configurations/arrangements in containers with different geometries and also the integration of heat pipes in latent heat storage systems.