Microencapsulated binary carbonate salt mixture in silica shell with enhanced effective heat capacity for high temperature latent heat storage

Microencapsulated phase change materials (MEPCM) with large active surface area can improve the system's effective heat capacity as a thermal storage medium. However, its usage in high temperature applications like concentrated solar power (CSP) has not yet been achieved due to the lack of a feasible microencapsulation method for high temperature compatible materials. This work reports novel process developed to achieve the first microencapsulation of a complex material system with high latent heat such like binary carbonate and its potential usage as a high temperature compatible thermal storage medium for CSP application. The MEPCM was demonstrated to be thermally stable up to 540 °C with a repeatable latent heat of 220 J/g. The MEPCM provides a 134.4% effective heat capacity enhancement for a temperature range from 400 °C to 540 °C compared to solar salt as a thermal storage medium. Finally, the proposed microencapsulation process was also shown to be applicable to other salt systems, showing its great potential for different application temperatures.