Preliminary performance analysis of a transverse flow spectrally selective two-slab packed bed volumetric receiver

A new volumetric receiver concept has been investigated, based on an adaptation of the spectrally selective, two-slab packed bed volumetric receiver concept of Flamant et al. Both slabs comprise spheres of identical size – borosilicate for the transparent slab 1 and SiC for the opaque slab 2 – which are ordered in a hexagonally close-packed bed. The flow direction has been changed from parallel to the incident radiation and perpendicular to the window, to parallel to the window and perpendicular to the incident radiation (transverse flow). The gap between the window and slab 1 has been removed, so the bed is held in place by the sidewalls, the floor and the window, allowing arbitrary orientation and dispensing with the need for beam-down operation. The receiver has been subjected to constant solar radiative load of approximately 70 suns, and the effect of variations in flowrate, the degree of air preheating as well as the thickness of slab 2 on the outlet air temperature distributions have been measured. ...