The effect of titanium dioxide nanoparticles on the phase diagrams and thermophysical properties of nitrate molten salts

Advisors: John Trevor Shelton.Committee members: Pradip Majumdar; Iman Salehinia.Includes bibliographical references.Includes illustrations.Due to their desirable thermophysical properties, nitrate molten salts are the main reason for studying the high-temperature storage medium in concentrated solar power plants. Low freezing point temperatures allow for safe operation of the power plant and for thermal energy storage fluids to be in a liquid state over an extended temperature range. Using portions of the obtained thermal energy to maintain the molten salt in its liquid state reduces the overall thermal efficiency of the power plant. Previous studies reveal that the addition of nanoparticles to the 60% NaNO₃-40% KNO₃ composition of molten salt decreases its freezing point temperature. The main objective of this study is to see how the freezing point temperatures of varying compositions of nitrate molten salts (30% NaNO₃-70% KNO₃|40% NaNO₃-60% KNO₃| 50% NaNO₃-50% KNO₃| 60% NaNO₃-40% KNO₃|70% NaNO₃-30% KNO₃) are effected when titanium dioxide nanoparticles of anatase phase of different volume fractions are added to it. In this study, nitrate molten salts are prepared and then tested using the differential scanning calorimeter (DSC) and scanning electron microscopy (SEM). The DSC tests allow for obtaining the thermal properties such as freezing point temperatures, specific heat capacities, and latent heat of fusion. Observations using the SEM provide an opportunity to quantify the morphological properties like size, the microstructure, and the dispersion of the nanoparticles in the molten salt.M.S. (Master of Science