Development and properties of n-octadecane / kaolinite composites as form-stabilized phase change materials for energy storage

Thermal energy storage (TES) is one of the promising options applied for obtaining energy-saving possibilities. This goal can be attained by using phase change materials (PCMs) that allow storing/releasing latent heats without losses caused by temperature differences. However, in most cases these materials need to be encapsulated for various applications, especially to prevent contamination and/or loss of substance. In this work, incorporation of a kind of an organic PCM belonging to the paraffins was performed by one step impregnation method. For this purpose, n-octadecane (n-OD) having 191.7 kJ/kg latent heat of melting and 34.2 οC peak melting temperature was used. In here, Kaolinite clay (KC), which was modified with cetyltrimethylammonium bromide in order to enhance the incorporation amount of n-OD, was utilized as the support matrices and called as m-KC. The development of form-stable composite PCMs was carried out by applying different recipes with varying the amounts of n-OD impregnation. Among the obtained composite PCMs, m-KC/OD30 having m-KC/n-OD: 70/30 composition ratio, demonstrated the highest TES capacity without any leakage during the usage. Accordingly, TES capacity and latent heat of melting peak temperature of m-KC/OD30 were found as 81.8 kJ/kg and Tpm = 30.4 °C, respectively. Based on the appropriate phase transition temperatures and favorable latent heat of melting value, the obtained form-stable composite PCMs can be implemented for the regulation of ambient temperatures in the low-medium temperature application fields, thus a cleaner process can be implemented by realizing energy savings.