Investigation of corrosive behavior of magnesium oxide nanoparticles in solar salt

Abstract

The global shift towards renewable energy has highlighted the critical need for sustainable and efficient technologies to address the growing energy demand and mitigate the environmental impact of fossil fuels. Concentrated Solar Power (CSP) systems, particularly parabolic trough collectors (PTCs), represent a promising solution due to their capacity for energy storage and dispatchability. This thesis focuses on advancing the cost-effectiveness and durability of CSP technologies by enhancing the thermal energy storage medium and protecting structural materials. A primary focus of this study is on molten solar salt (a binary eutectic mixture of NaNO₃ and KNO₃), commonly used as a heat transfer fluid (HTF) in CSP systems. While molten salts offer thermal stability and economic advantages, their relatively low specific heat capacity limits their efficiency. To address this, the thesis investigates the incorporation of magnesium oxide (MgO) nanoparticles into molten salts to improve specific heat capacity, leveraging the unique properties of nanofluids. Experimental results demonstrate significant improvements in thermal performance, reduced investment costs, and enhanced energy storage efficiency. Corrosion is a critical challenge in CSP systems, particularly at elevated temperatures. The thesis explores nickel coatings, specifically electrolytic and electroless nickel-phosphorus (Ni-P) coatings, as protective layers for stainless steel components exposed to molten salts. Both coating methods are analyzed for their ability to mitigate corrosion. The integration of advanced nanofluids and protective coatings contributes to extending the service life and reducing operational costs of CSP systems. This research provides valuable insights into material and process optimization for renewable energy technologies, promoting their broader adoption as sustainable energy solutions.