Experimental measurements and XCT based simulation of effective thermal conductivity of stacked ceramsites in molten-salt tank foundation

Abstract

Solar energy is a sort of potential renewable energy in the future. Ceramsite is a kind of porous material with resistance to pressure and high temperature to be applied in the molten salt storage foundation of concentrated solar power plant (CSP), whose thermal conductivity is influential to the size of foundation and safety of system. Under this prospect, a hot wire instrument was designed independently for researching the thermal properties of stacked ceramsites with different particle size, density and porosity. The thermal conductivity varied from 0.089 to 0.113 W/mK when porosity decreased from 67.9 to 56.7%. In addition, X-ray computed tomography was used to analyze the porous distribution of stacked sample. Finally, the effective thermal conductivity was estimated by simulation based on the XCT data. The CT-simulation value of effective thermal conductivity ranged from 0.087 to 0.104 W/mK decreasing with porosity of 67.8 to 59.6%. The difference between the effective thermal conductivity obtained by hot wire experiment and XCT simulation is less than or equal to 1.1%, which, to some extent, verifies the accuracy and reliability of the two methods.