Encapsulation of Inorganic Phase Change Materials by Sol-Gel Method for Thermal Energy Storage
Abstract
The macroencapsulation of inorganic phase change materials (PCMs) for eventual application in latent heat thermal energy storage (LHTES) is herewith carried out by a multi-step preparation procedure. These steps are (1) pelletization and sintering (using different granulation techniques); (2) surface treatment (forming an intermediate polymeric layer) and coating via sol-gel method; and (3) final thermal treatment for the densification of the ceramic layer and polymer removal. Effectiveness and reproducibility of each procedure step as well as quality of layers were elucidated by means of Scanning Electron Microscopy (SEM) with Energy-Dispersive X-ray spectroscopy (EDX) and mechanical crush tests. Macro-encapsulation procedure was optimized analyzing the thermal performance of capsules by Thermo-Gravimetric Analysis and Differential Scanning Calorimetry (TGA/DSC) and in a conventional oven.