M.S. (Master of Science)
Department of Mechanical Engineering
Today there is a strong motivation to explore the possibility of harnessing solar thermal energy around the world to produce electricity. Thermal energy storage (TES) is extremely important in concentrated solar power (CSP) plants as it allows the plants to have energy availability and dispatch ability using industrial technologies. Rankine cycle is used to determine the efficiency of the CSP plants, the efficiency of the cycle is increased by 40% when the present working fluid (Therminol VP-1 whose efficiency is between 10--25%) is replaced with molten salts (a combination of 60 wt% NaNO3 and 40 wt% KNO3). Molten salts are used in CSP plants as a TES material because of the following advantages: high specific heat capacity and high thermal stability. Their main drawbacks are their relative poor thermophysical properties and the instability of molten salts above 550℗ʻC. To study the effects of nanoparticles (particles between 1 and 100 nanometers in size) on the drawbacks of fluids, the fluids are doped with nanoparticles thus obtaining the salt-based nanofluids. The present study experimentally determines the effect of nanoparticles (silicon and titanium dioxide) on the decomposition temperature of molten salts at elevated temperatures. Specific heat capacity is measured by using a differential scanning calorimeter (Perkin Elmer DSC 7), the experiment work has been carried out at different temperature range (400℗ʻC to 575℗ʻC). The size distribution of nanoparticle clusters present in the salt at each concentration was evaluated by means of scanning electron microscopy (SEM). Thermogravimetric analysis (TGA) was carried out to study the mass loss and activation energy of the molten salt at elevated temperatures with varying mass concentrations of nanoparticles (1%, 5% and 9%).
Pogula, Shalini, "The effect of silicon dioxide and titanium dioxide nanoparticles on the thermal decomposition characteristics of molten salts at elevated temperatures" (2017). Graduate Research Theses & Dissertations. 5557.
ix, 43 pages
Northern Illinois University
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