Investigation of the thermal conductivity of RT58 phase change material during the charging process of a thermal storage tank under natural convection conditions

As global energy demand grows, more and more attention is being paid to efficient energy storage solutions, among which Phase Change Materials (PCMs) are particularly promising. They allow efficient thermal energy storage by using the latent heat that is absorbed or released during the transformation of the aggregate state. One of the most important properties of PCM for efficient heat transfer is the thermal conductivity. Unfortunately, it is not high for organic materials. This paper presents a study of RT58 PCM, presenting an experimental evaluation of the thermal conductivity of this material and the application of the material in a storage tank. The analytical evaluation focuses on the heat transfer under natural convection conditions, where the aim is to assess the influence of the thermal conductivity of the PCM on the amount of energy stored in the storage tank. In this case, the temperature of the heating surface, the magnitude of the thermal conductivity coefficient and the choice of the other PCM are considered. The experimental results allowed to refine the value of the thermal conductivity coefficient of the RT58 material used (0.188 W/(mK)) and the analytical calculations allowed to trend towards an increase of the heat exchange efficiency of the system with the PCM.