MODELING AND OPTIMIZATION OF A 2-SLAB SELECTIVE VOLUMETRIC SOLAR RECEIVER

The two-slab volumetric receiver is theoretically studied and the resu lts are compared with experimental data. Two systems are described; fo r both of them, slab 2 is composed of SiC particles. Slab 1 is made of glass beads for the first system and silica honeycomb for the second system, the latter being the more efficient. Predicted and measured da ta show that the efficiency ranges between 70 and 75% for a gas outlet temperature of 1100 K. Predicted results are proved to be very sensit ive to slab 1 depth, optical properties, and to the numerical solution of the radiative transfer equation. Band models and a discrete ordina te method are used in this paper. Finally the variation of the receive r efficiency is calculated as a function of slab 1 scattering albedo; a maximum efficiency of about 90% is reached at 1300 K for albedos in the solar spectrum and the infrared region equal to 0 and 1, respectiv ely.