Experimental and Numerical Characterization of Ceramic and Metallic Absorbers under Lab-scale Conditions

Volumetric receiver technology has a huge potential for increase in the receiver and power block efficiencies by reducing the radiative thermal losses and increasing the temperature of the heat transfer fluid. With the aim of improving the thermal behavior of these types of receivers, CIEMAT-PSA is working at lab-scale on different configurations and geometries to optimize absorber behaviors. Furthermore, simplifiedComputational Fluid Dynamics (CFD)modelshave been developed to determine their feasibility for the prediction of the receiver experimental behavior and to analyze the heat transfer and thermal losses produced.As part of this work, experimental results ofboth a SiC absorber and an alloy-601 onetested under lab-scale conditions,under similar outlet receiver temperatures, were assessed. Moreover, the numerical results obtained froma two dimensional (2D) CFD model, which considers thermal equilibrium between solid and fluid phases, have been presented for the selected experimental data. The deviation between the experimental thermal efficiency and the numerical one was lower than 10%, showing a good agreement for a first-approach CFD model. The average thermal efficiency reached under lab-scale conditions was around 90% in both cases.