Experimental Study of Thermal Energy Storage Rates in High Temperature Phase Change Systems for Solar Refrigeration
Abstract
High temperature thermal energy storage (TES) may play an important role in solar applications, becoming a key issue to increase the global effectiveness of this type of installations. Different sorts of thermal storage technologies in high temperature were reported in Gil et al. (2010). The key issue of TES systems is the selection of the best storage material for each application (Zalba et al., 2003; Medrano et al., 2010). The thermal properties of the material (basically the range of melting temperature and the enthalpy of phase change), the conservation of these properties after several thermal cycles, and possible corrosion problems with the container are some of the important aspects to take into account during the selection of the storage material. In order to test these characteristics experimental analysis with TES units are needed. Ait Adine et al. (2009) carried out a numerical analysis and experimental validation of the behavior of thermal properties of two phase change materials (PCM) in a shell-and-tube heat storage unit. The PCM were located around an only tube and their melting temperatures were 50 ºC and 27.7 ºC. This work assumed that the effect of natural convection during melting could be taken into account by using an effective thermal conductivity of the liquid phase of the PCM. This assumption will be taken in account too in the present work.