Tailored edge-ray concentrators for solar energy applications: approaching the thermodynamic limit to concentration

We present a new type of ideal non-imaging secondary concentrator, the tailored edge-ray concentrator (TERC), that can closely approach the thermodynamic limit of concentration, and illustrate it for both linear and point-focus Fresnel reflectors. For large rim-angle heliostat fields, practical-sized secondaries with shapes that should be relatively easy to fabricate can achieve concentrations substantially above those of compound parabolic concentrators (CPCs). This superiority stems from designing so as to accommodate the particular flux from the heliostat field. The edge-ray principle used for generating the new secondary dictates a heliostat tracking strategy different from the conventional one, but equally easy to implement.