Advanced high temperature semi-transparent solar absorbers

Theoretical analysis of the interaction between concentrated solar radiation and a honeycomb matrix or a bed of particles cooled by a gas is presented. The computation and the experimental results show evidence of overheating of the solid near the irradiated surface. To prevent the upper surface from this phenomenon and to reduce the radiative heat losses, we propose to use selective semi-transparent porous absorbers. The first results about coatings on silica are presented.