Insight into effects of molten KNO3-NaNO2-NaNO3 volumetric absorption of solar radiation from different factors by absorption spectroscopy

Volumetric absorption of solar radiation (VASR) is an important parameter which directly determines the absorption efficiency of molten salt as the direct receiver. Accordingly, VASR directly impacts on power generation efficiency. Therefore, investigating the VASR is dramatically important involving calculation method and the effect factors. Molten nitrate/nitrite salt of 53 wt% KNO3-40 wt% NaNO2-7 wt% NaNO3 (HTS) on account of low melting point and high specific heat etc. merits was used in concentrate solar power field, so it was selected to be studied in this work High-temperature ultraviolet-visible (UV-Vis) and infrared absorption (IR) spectrometers built by ourselves were used to obtain the absorption spectra of HTS. A calculation method was established by ourselves, based on which the VASR was calculated. Furthermore, various effects coming from bubbles, temperature, and additive were also studied. This will supply important help for the design of solar power plant. (C) 2019 Published by Elsevier B.V.