Precise Viscosity Analysis of Alkali Metal Molten Salts at High Temperature

Abstract

Recently, solar thermal energy has been attracted considerable attention as a renewable energy alternative to fossil fuels. The operation and efficiency of solar thermal energy plants employing thermal energy storage techniques have been proved at both experimental and commercial scales.1 In solar thermal energy plants, alkali metal molten salts have recently attracted as thermal storage media and heat transfer fluids, because these salts have a low melting point, high heat capacity, and moderate energy density.2 In addition, alkali metal molten salts are less expensive and more environmentally friendly than currently available high-temperature oils. However, many investigations are scarce focusing on thermophysical properties of molten salts at high temperature. In particular, the viscosity of alkali metal molten salts is few reported and the reported viscosities are shown larger difference by analysis method or other one. In this study, therefore, we are measured the viscosity of alkali metal molten salts at high temperature above 500 °C by rotation method using high temperature rheometer system (MCR 502, Anton Paar) and reliability of obtained viscosity values is evaluated.3 This work was supported by Council for Science, Technology and Innovation (CSTI), Cross-ministerial Strategic Innovation Promotion Program (SIP), "energy carrier" (Funding agency: JST). References Q. Peng, X. Yang, J. Ding, X. Wei, and J. Yang, Appl. Energy, 112 (2013) 682.S.M. Flueckiger and S.V. Garimella, Sol. Energy, 86 (2012) 1631.S.W. Kim, K. Uematsu, K. Toda, and M. Sato, J. Ceram. Soc. Jpn., (2015) in press.