Integrated analysis on the volumetric absorption characteristics and optical performance for a porous media receiver

The absorption of concentrated solar radiation within volumetric receiver is the key step that governs the global efficiency of solar thermal systems. An integrated radiative transfer model combined the dish concentrator, solar window and porous absorber is developed. The distribution of absorbed radiation energy in the porous absorber and the optical performance of the entire system are investigated by a Monte Carlo ray tracing simulation. The detailed radiation transport within the solar window and porous absorber is fully considered. The effects of porous structure parameters, slope error of concentrator and the alignment error of receiver are analyzed. The results show that the optical losses due to the back scattering from porous absorber and the absorption and reflection of solar window have a significant influence on the optical performance of system. The porous structure parameters greatly affect the distribution of solar radiative source within the porous absorber. In addition, the optical efficiency decreases noticeably when the slope error and alignment error exist.