James D. Oxley1, Jose Mendez1, and Anoop Mathur2
1Southwest Research Institute, San Antonio, TX 78238, USA; 2Terrafore, Minneapolis, MN, 55402, USA
Encapsulated potassium nitrate was developed for use as a high temperature phase change material in solar thermal energy storage applications. Fluid bed coating was used to apply three separate layers to a potassium nitrate prill for mechanical stability and accommodation of thermal expansion by the salt during its phase change. The capsule is stable above 500 degrees C and thermal cycling through the 334 degrees C melting point of the salt was demonstrated.