Document Type

Honors Thesis


Solar thermal energy is an important energy source because of its abundance. Solar thermal energy can be stored and reused in systems like concentrated solar power (CSP) plants. In addition to the sensible heat, which is associated with temperature rise, latent heat associated with the phase change can also be utilized to store heat. The study of the composition of heat transfer fluid (HTF) and the phase change material (PCM), that can survive high temperatures (above 3000C), has not been done extensively. In this work, solar salt, which is a mixture of potassium nitrate and sodium nitrate salts, has been used as the HTF, silica as the encapsulation material, and lithium carbonate-sodium nitrate as the PCM. Sol-gel method has been used to make silica. Scanning Electron Microscopy (SEM), X-ray mapping, Fourier-transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM) have been used in the verification of the formed capsules. An increase of 40.5% high specific heat and 134.4% latent heat in the heat capacity throughout the HTF was found in the study. The results show that the microencapsulation method provides stable results and works for different types of molten salts. The findings from this research can have significant impact on the design of storage systems for solar thermal energy.

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