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

Abstract

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 hightemperature heattransfer fluid (HTF) for concentrated solar thermal power (CSP) technology. The acceptable range of the working temperatures for the HTF is from below 250 آ°C to at least 800 آ°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. Datafitted 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 hightemperature HTF and thus are recommended as a new generation hightemperature HTF.