Al2O3 nanoparticles integration for comprehensive enhancement of eutectic salt thermal performance: Experimental design, molecular dynamics calculations, and system simulation studies

Eutectic salts, a promising thermal storage material for the next generation of concentrating solar power plants, have attracted extensive attention. Its thermal performance is a crucial factor affecting the efficient utilization of efficient solar energy. Utilizing NaCl–KCl–LiCl as the phase-change material and introduced Al2O3 nanoparticles to enhance thermal conductivity, thus study explores potential mechanisms for improving heat transfer and thermal storage performance. Experimental and molecular dynamics results consistently showed that doping Al2O3 nanoparticles significantly increased the specific heat and thermal conductivity of eutectic salt. Specifically, at a nanoparticle content of 1.0 wt%, liquid-specific heat and thermal conductivity increased by 44.58 % and 21.43 %, respectively. Experimental and simulation results mutually validated a consistent upward trend. However, nanoparticle introduction unavoidably led to increased viscosity, with a maximum increase of 32.15 %. Subsequently, detailed simulation analysis of a shell-and-tube heat storage unit for composite materials highlighted that heat conduction rate was influenced by both natural convection and heat conduction. Therefore, viscosity and thermal conductivity should be simultaneously considered in the system applications. This scientific strategy holds promise for widespread application of eutectic salts in solar thermal energy storage, further promoting sustainable development of renewable energy.