Survey and evaluation of equations for thermophysical properties of binary/ternary eutectic salts from NaCl, KCl, MgCl₂, CaCl₂, ZnCl₂ for heat transfer and thermal storage fluids in CSP

Considered as promising candidates of composing eutectic chloride molten salts for high temperature heat transfer fluid (HTF) with low corrosivity to nickel-based alloys, NaCl, KCl, MgCl₂, CaCl₂, and ZnCl₂ are formulated into proper binary and ternary mixtures to satisfy the property requirement for HTFs. Experimental and predicted thermophysical properties of 16 selected eutectic binary and ternary molten salts are provided. The molten salts can work in a temperature range from after eutectic melting to at least 800 °C with low vapor pressure and acceptable low corrosivity. Surveyed equations and correlations for thermophysical properties of salt mixtures are used to predict heat capacity, density, thermal conductivity, and viscosity. The results are compared to experimental data from the author's tests as well as reported in literature. Evaluated equations and correlations that can better predict the transport properties of the salts are selected and recommended. Authors expect that more experimental tests will be conducted to provide data for application in CSP industry.