Modeling for Thermal Conductivity of Ternary Molten Nitrate Salts Using Unit Cell Concept

Molten nitrate-based salts find potential use as a heat transfer fluid as well as thermal energy storage fluid in concentrating solar power plants primarily due to their relative inertness to construction materials and lower viscosities. It has been observed that ternary nitrate salt mixtures have lower melting points as compared to binary mixtures. One important property looked at during material selection is the thermal conductivity. Experimental determination of this property is laborious and the uncertainties are high. In this paper, the unit cell model proposed earlier by Zhao et al. has been extended to ternary systems. It is observed to have better prediction as compared to the linear mixing rule (additive rule) as well as the model proposed by Hossein et al. The thermal conductivity of calcium nitrate has also been predicted. This will help in modeling thermal conductivity of Ca(NO3)(2)-based ternary salts, which currently exhibit even lower melting points and viscosities as compared to its binary counterparts.