The eutectic mixture of MgCl2–KCl molten salt is a high temperature heat transfer and thermal storage fluid able to be used at temperatures up to 800 °C in concentrating solar thermal power systems. The molten salt thermophysical properties are reported including vapor pressure, heat capacity, density, viscosity, thermal conductivity, and the corrosion behavior of nickel-based alloys in the molten salt corrosion at high temperatures. Correlations of the measured properties as functions of molten salt temperatures are presented for industrial applications. The test results of tensile strength of two nickel-based alloys exposed in the molten salt at a temperature of 800 °C from 1-week length to 16-week length are reported. It was found that the corrosion and strength loss is rather low when the salt is first processed to remove water and oxygen.

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Three eutectic salts from a system of halide salts NaCl–KCl–ZnCl2 were chosen for detailed study of thermal and transport properties with the objective of developing a next generation high-temperature heat-transfer fluid (HTF) for concentrated solar thermal power (CSP) technology. The acceptable range of the working temperatures for the HTF is from below 250 °C to at least 800 °C. The tested properties are presented here for the three candidate eutectic salts, including melting point, heat of fusion, heat capacity, vapor pressure, viscosity, density, and thermal conductivity. Data-fitted equations are provided for all the measured properties for convenience in engineering application. It is concluded that the three eutectic salts can satisfy the needs for a high-temperature HTF and thus are recommended as a new generation high-temperature HTF.

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Concentrated solar power (CSP) technologies tend to work at more and more high temperatures, which correspondingly need a high temperature heat transfer fluid (HTF) to transmit the heat from solar concentrator to power plant. The objective of this work is to study heat capacities of a HTF which can work at upper limit temperature of around 850 °C. The ideal HTF should have low melting temperature and be thermally stable at high temperatures. High specific heat capacity is also favorable. The eutectic ternary salt mixtures studied in this work are formed by NaCl, KCl and ZnCl2. The heat capacity, heat of fusion, and melting temperatures of three salt mixtures were measured by using Differential Scanning Calorimetry (DSC)/Thermal Gravimetric Analysis (TGA) simultaneously. The accuracy of the measurements was validated by measuring three metals, Indium, Tin, and Zinc, which have standard reference data. Each of the three eutectic mixtures by NaCl-KCl-ZnCl2 ternary system had 10 to 11 samples tested for heat of fusion, the melting point, and heat capacity. Mixing rule from literature was used to estimate the heat capacity of the new HTF, which showed very good agreement to experimental data.