The Effects of Nanoparticle Augmentation of Nitrate Thermal Storage Materials for Use in Concentrating Solar Power Applications

The Effects of Nanoparticle Augmentation of Nitrate Thermal Storage Materials for Use in Concentrating Solar Power Applications. (May 2011) Matthew Robert Betts, B.S., Georgia Institute of Technology Co-Chairs of Advisory Committee: Dr. Thomas Lalk Dr. Michael Schuller The Department of Energy funded a project to determine if the specific heat of thermal energy storage materials could be improved by adding nanoparticles. The standard thermal energy storage materials are molten salts. The chosen molten salt was a sodium nitrate and potassium nitrate eutectic, commercially called Hitec Solar Salt. Two nanoparticle types were chosen, alumina and silica. The nanoparticle composite materials were fabricated by mixing the components in an aqueous solution, mixing that solution for a set amount of time using a sonic mixer, then removing the water from the aqueous solution, leaving the composite molten salt behind as a fine white powder. The thermal properties of the composite and plain material were measured using two techniques: American Society for Testing and Materials (ASTM) 1269E and Modulating Differential Scanning Calorimetry (MDSC). These two techniques measured the specific heat and the heat of fusion of the plain and composite materials. The results of all the ASTM and MDSC measurements suggest that the addition of the nanoparticles using the given manufacturing technique increased the specific heat of the molten salt by approximately 20%, with both measurement techniques showing approximately the same level of increase. The silica and the alumina improved the specific heat by nearly the