Nanoparticle Dispersions on Ternary Nitrate Salts for Heat Transfer Fluid Applications in Solar Thermal Power

In this study, we report enhancement in heat capacity of SiO₂ nanoparticle dispersions in a molten ternary nitrate salt (NaNO₃, KNO₃, and Ca(NO₃)₂) to obtain an effective heat transfer fluid (HTF)/thermal energy storage (TES) for concentrated solar power (CSP) application. The enhanced heat capacity of the molten salt mixture is expected to greatly increase thermal storage density of HTF/TES, and thus the cost of electricity produced by CSP plant can be significantly reduced. A custom two-step method was used to synthesize SiO₂ nanoparticle/ternary salt mixture. The nanoparticle concentration of the mixture was fixed at 1% by weight for comparison with the previous studies. A modulated differential scanning calorimeter (MDSC) was employed to measure heat capacity of the mixture, and it was found to be enhanced by ∼19% compared to the pure ternary salt.