Experimental study of innovative periodic cellular structures as air volumetric absorbers

This work presents an experimental thermal evaluation of new and innovative porous morphologies suitable for volumetric solar receivers. Five new morphologies, four of them based on the repetition of single unit cells: diamond, rotated cube, tetrakaidecahedron, cube shifted, and a random morphology following the Voronoi tessellation technique were tested. In addition, for emerging geometries, two different cell size configurations were evaluated: one with constant cell size dimension and one with cell's size changing with flux direction. All the lattices were analysed experimentally in a lab-scale solar simulator. The results were compared with the ones of the already established and more conventional silicon carbide honeycomb and random foams proving that a gain in performance is achievable with the Voronoi morphology, both with constant cell size and increasing cell size pattern.