Preparation and Characterization of n-Nonadecane/CaCO3 Microencapsulated Phase Change Material for Thermal Energy Storage

A novel microencapsuled thermal energy storage phase change material (MicroEPCM) based on n-nonadecane core and CaCO3 shell were synthesized via a self-assembly method. The chemical structure, surface morphology and thermal properties of the MicroEPCM were investigated by X-ray diffractometer (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermogravimetric analyzer (TGA), respectively. The effects of core/shell mass ratios, stirring speed, temperature and emulsifier concentration on the morphology and thermal properties of the MicroEPCM were investigated to confirm the most suitable CaCO3-encapsulated n-nonadecane reaction conditions. The results showed that the optimal spherical morphology and the highest latent heat were obtained when the stirring rate is 800 rpm, the temperature is 45 degrees C, the emulsifier concentration is 15 mmol/L and the core/shell mass ratio is 3:1. The latent heat and encapsulation rate of MicroEPCM as above-mentioned are 134.83 J/g and 59.68%, respectively. The thermal conductivity of MicroEPCM is improved up to 3.56 times than that of prinstine n-nonadecane. The MicroEPCM did not leak after being heated at 80 degrees C for 20 h, which proves that the CaCO3 shell is compact. The MicroEPCM present a good thermal stability after 200 thermal cycling. The MicroEPCM also has been proved to maintain high mechanical strength.