Wet Impregnation Method for Synthesis of Phase Change Composite of N-Octadecane in Porous Silica Gel

Abstract

Thermal energy storage is gaining more interest as people aim to utilization of solar energy. The thermal energy can be stored in the form of latent heat and used for building applications that require increasing energy. This report investigated the wet impregnation method for the synthesis of thermal storage material, namely phase change composite (PCC) for two purposes: to create a simple method for the synthesis of PCC and study behaviors of phase change material (PCM) when confined inside the pore. Particularly, the PCC was synthesized using n-octadecane and silica as PCM and porous matrix, respectively. The characterization of the product was conducted by various analytical methods: N2 adsorption/desorption isotherm, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA). Results showed that the n-octadecane was successfully impregnated into a silica porous network through simple steps of the wet impregnation method. The porosity analysis confirmed the confining of PCM inside matrix pores. The n-octadecane was easily kept inside pores by the capillary and surface tension forces.  without any chemical interaction. At maximum impregnation, n-octadecane accounted for 70% of the composite. This sample presented a shape-stability at up to 90 oC, provided a latent heat of 145 J g-1, and was selected as optimal PCC.