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 higherature 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 higherature HTF and thus are recommended as a new generation higherature HTF.