Heat and mass transportation properties of binary chloride salt as a high-temperature heat storage and transfer media

Abstract

Molten binary chloride salts are considered as promising heat transfer and storage mediums in a Concentrating Solar Power (CSP) Station. The properties of them over the entire operating temperature are required to be calculated, since they are difficult to be measured under high-temperature conditions. Reliable numerical method is an alternative tool to accurately predict thermal properties of molten salts from the viewpoint of micro-structure. Based on the effective Born-Mayer-Huggins (BMH) pair potential model, the local structures and thermodynamic properties of lithium-potassium chloride were computed by using Molecular Dynamics simulations (MD) and the results are consistent with available experimental literature data. The simulation results prove that BMH force field is reasonable to be adopted to predict the properties of various molten chloride salts and their mixtures. The minimum errors of thermal properties above are all within 11.1%, which is accurate and reliable. The results show that Li+ promotes the diffusion of the system efficiently. In addition, the specific heat capacity and thermal conductivity are significantly improved with the increase of Li+. The database of thermal properties and structures of this work are significant for accurate design of material structure and regulation of thermal storage system performance.