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A theoretical model for predicting the temperature-dependent thermal conductivity of pure molten salts, both simple and complex, is presented. The model is based on kinetic theory and incorporates Einstein's concept of minimum thermal conductivity. The proposed formulation can consider the magnitude of thermal conductivity for separate salts, including complex and polymerizing salts. The model's thermal conductivity predictions were compared to reliable experimental data in the literature and a previously recommended thermal conductivity model using the Bland–Altman method. The comparison showed accurate thermal conductivity predictions relative to the reliable experimental data, with an average deviation of 10% or less. The model's predictions were also compared to the experimental data on an individual basis for halide, divalent halide, carbonate, nitrate, nitrite, sulfate, and hydroxide molten salts, demonstrating reliable predictions for the molten salts studied and improved accuracy over the previous model. Lastly, a database of simple and complex molten salts, with the necessary parameters for modeling their thermal conductivity, is recommended. • A database for the thermal conductivity of more than 60 molten salts is presented. • The model is developed based on the kinetic theory. • Few key thermophysical properties are required for the model parameterization. • The predictive capability of the model is found to be very good. • The model is valid from the melting temperature up to 75% of the boiling temperature. [ABSTRACT FROM AUTHOR]

Highlights • A novel flux mapping system which featured two Lambertian targets was first introduced and developed. • The design principle and the hardware implementation were presented in detail. • The performance of a multi-lamps high-flux solar simulator was evaluated by the flux mapping system. • The repeatability precision and the relative error of the flux mapping system were tested and analyzed. Abstract It is an important and challenging work to measure the energy flux density distribution of the concentrated radiation during the concentrating solar power applications. In order to evaluate the performance of a multi-lamps high-flux solar simulator, a novel flux mapping system based on the indirect method has been developed. It features two Lambertian targets. One is a stationary water-cooled Lambertian target where there is a circular hole in the center used to install a flux sensor. The other is a movable Lambertian target used to cover the flux sensor when shooting the concentrated light beam image. This kind of design can obtain the gray value of flux sensor region directly and does not require the interpolation in the sensor-influencing area. The design theory and principle, the hardware implementation and the experimental validation of this flux mapping system have been presented in detail. The repeatability experiments and the error analyses showed that the total relative errors of this flux mapping system were ±8.1% with a repeatability of 1.1%, and ±8.5% with a repeatability of 2.7%, for evaluating the flux and the total radiant power, respectively. [ABSTRACT FROM AUTHOR]