Preparation and Characterization of Bio-based PCM Microcapsules for Thermal Energy Storage

Phase change materials (PCM) have gained extensive attention in thermal energy storage applications. During their phase transition, the energy can be stored in or released from PCM. While changing from solid state to liquid state, PCM start to flow. Encapsulation is a widely-used technique to prevent PCM from migrating and reacting with their environment. In the first phase of the thesis, microencapsulation of 100% bio-based (organic) PCM microcapsules by solvent evaporation and oil-in-water emulsification was investigated under different conditions, resulting in optimal properties. For the second phase, the focus was on the studies of inorganic PCM, which have higher latent heat of melting, higher thermal conductivity and lower price than the organic PCM. However, their supercooling, phase segregation, and hydrophilic nature have caused major challenges to their applications. Tuning the thermal properties, including crystallization temperature and phase segregation of inorganic PCM by using bio-based nanoparticles and other additives was investigated in the second part of the research. Due to the hydrophilic nature of the inorganic PCM, a double emulsion (water in oil in water) solvent evaporation technique was explored for encapsulation with a polymeric shell. The challenges and strategies for supercooling prevention and encapsulating the hydrophilic PCM were investigated.