An astigmatic corrected target-aligned solar concentrator

Highly concentrated solar energy is required for solar pumping of solid sta te lasers, and for other applications. High concentration may be obtained b y a combination of a primary concentrator with f/D > 2. in addition to a no n-imaging concentrator, We have designed and constructed a novel tower prim ary concentrator. A 3.4 m diameter primary mirror, composed of 61 segments, was mounted on a commercial two-axis positioner. Unlike the common zenith mounting, the positioner fixed axis is directed southwards, pointing at 32 degrees above the horizon. With this novel mounting, the concentrator is th e first implementation of the astigmatic corrected target aligned (ACTA) de sign which flattens the irradiation density variation during the day. The p rimary mirror segments are each mounted on a separate two-axis mount, and a ligned to compensate for astigmatism. The segments are spherically curved w ith R = 17 m radius of curvature, while their vertexes are placed on an R/2 = 8.5 m radius spherical cap. A four-segment plane mirror reflects the lig ht towards a horizontal focal plane. We have measured the absorbed solar po wer into a 89 x 91 mm(2) rectangular aperture and found good agreement with optical design calculations. Peak solar concentration in the focal plane e xceeded 400 suns. (C) 2000 Published by Elsevier Science B.V. All rights re served.