Thermal and Transport Properties of NaCl-KCl-ZnCl2 Eutectic Salts for New Generation High-Temperature Heat-Transfer Fluids

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 degrees C to at least 800 degrees 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.