THE OPTICS OF THE SOLAR TOWER REFLECTOR （的光学太阳反射器）.pdf

yyyxxxzk;2uoo0ttii;1yyzzzzkkccuu(2)i; THE OPTICS OF THE SOLAR TOWER REFLECTOR Akiba Segal and Michael Epstein Solar Research Facilities Unit, Weizmann Institute of Science, P.O. Box 26, Rehovot, 76100, Israel, Phone: +972 8 9342935, Fax: +972 8 9344117, E-mail: a.segal@weizmann.ac.il Abstract 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. 1. INTRODUCTION only a reflective surface having two foci is capable of this mission, namely, each ray that is oriented to one of its The experience gained during the last two decades in foci (which coincides with the aim point of the heliostat developing appl