Measurement of the Basic Properties of Ternary Eutectic Chloride Salts Used as High Temperature Heat Transfer Fluids and Thermal Storage Media

Abstract

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.

Experimental Test of Properties of KCl–MgCl2 Eutectic Molten Salt for Heat Transfer and Thermal Storage Fluid in Concentrated Solar Power Systems

“…The measurements of melting point, heat of fusion, and the specific heat capacity were carried out using a simultaneous differential scanning calorimetry and thermogravimetric analysis (TG) system (Model STA449 F3 made by NETZSCH). The reliability of this system was checked in our previous work for the measurement of eutectic salts NaCl-KCl-ZnCl 2 [18]. The results in that work showed that the difference in melting point and the deviation of the heat of fusion were below 61 C and 4.5%, respectively, when compared to data in literature [18].…”

“…The reliability of this system was checked in our previous work for the measurement of eutectic salts NaCl-KCl-ZnCl 2 [18]. The results in that work showed that the difference in melting point and the deviation of the heat of fusion were below 61 C and 4.5%, respectively, when compared to data in literature [18].…”

Molten Salt Thermophysical Properties Database Development: 2019 Update

“…The melting point and specific heat capacity of the MgCl2-KCl samples were measured using a simultaneous differential scanning calorimetry and thermogravimetric analyses system (STA449 F3 NETZSCH). The calibration of the instrument is discussed in Dehghani et al, 2016. Ten separate melting point and heat capacity measurements with fresh 32-68 mole % MgCl2-KCl samples were performed.…”