Preparation and study on thermophysical properties of inorganic salt hydrate as energy storage materials

In this paper, the preparation methods of new inorganic salt hydrate mixtures and their experimentally tested thermophysical properties are presented. Two inorganic salt hydrates mixed together at different weight proportions to study their thermodynamic properties for energy storage applications. Three samples having weight proportions of salt mixtures as 70:30, 80:20 and 90:10 are prepared and Differential Scanning Calorimetry (DSC) is used as a thermal analyzer to find the thermal stability of the samples. The DSC results of the salt hydrate are observed for determining the melting temperatures, latent heats and specific heats during melting and freezing process. The melting point, heat of fusion, and heat capacity of the salt hydrate samples are observed as 46.6 °C , 133.81 J/g and 8.75 J/gK for 70:30, 47.28 °C, 169.91 J/g and 15.95 J/gK for 80:20 and 47.26 °C, 173.96 J/g and 14.20 J/gK for 90:10. The time requirements for the completion of melting and freezing process of the salt mixture results are compared. Thermal and heat transfer characteristics of the newly prepared salt mixtures are experimentally investigated for the purpose of recommending it to use as thermal energy storage medium. The inexpensive inorganic salt hydrate mixtures, with greater enthalpy, higher heat storage capacity and good thermal reliability, shows great potential for heat storage applications in the low temperature solar thermal applications like water heaters, building space heating applications, domestic solar cookers and dryers.