ON THE ANALYSIS OF SURFACE ERROR DISTRIBUTIONS ON CONCENTRATED SOLAR COLLECTORS

The distribution of surface normal deviations from an ideal shape on c oncentrating solar collector surfaces is used to define the optical qu ality of a reflector. These distributions can be modeled by considerin g them to ideally follow a two-dimensional, circular Gaussian distribu tion. However, the measurement of these deviations in experimental sys tems usually defines only that component of the surface normal that de viates from the ideal surface normal direction, and ignores the rotati onal component of the normal vector in the plane perpendicular to the ideal direction. To compare the measured one-dimensional radial distri bution with the expected two-dimensional model, we must transform the two-dimensional model into the appropriate radial distribution. The fo llowing analysis describes this transformation, and presents results g ained from an application of the analysis to measured surface normal d ata from a min or panel used in the reflecting surface of the 400 m(2) paraboloidal (''Big Dish'') concentrator constructed at the ANU.