The Optics of the Solar Tower Reflector

− The concept of the reflective solar tower is based on inverting the path of the solar rays originating from a heliostat field to a solar receiver that can be placed on the ground. This system is based on the property of a reflective quadric surface to reflect each ray oriented to one of its foci to its second focus. Two shapes of surfaces can be used: one is concave − the ellipsoid, and the other is convex − the hyperboloid (with two sheets). This study analyzes the achievable optical performances of these types of reflectors and proves that the hyperboloidal surface is a superior reflector. The optics of the hyperboloid is analyzed in detail.