Focal width correcting lens system for concentrating sunlight

Abstract

Linearly imaging converging lenses situated in parallel, which track the elevation of the sun around their east-west axis, have a high degree of area usage and are therefore particularly suitable for architectonic integration. They act selectively in regard to the incident solar radiation, because they convert the direct sunlight via receivers situated in their focal lines into useful energy, and illuminate the spaces lying underneath with pleasant diffuse light. Their weak point is that they change the focal width and the lateral displacement of the focal line as a function of the solar azimuth angle. The present invention describes a tracking system which transfers the geometrical conditions into a mechanical coupling system which corrects the focal width and the displacement of the focal lines exactly and simultaneously. The tracking system represents a mechanical analog computer which solves trigonometric equations using nested orbit functions.

1 . A tracking system for correcting the focal width and the focal line offset in lenses which are positioned east-west and are tracked in elevation, characterized in that a mechanical coupling system performs both corrections simultaneously. 
   
   
       2 . The tracking system according to  claim 1 , wherein both sets of position information are given by the path curve which a solar vector rod rotating on the circumference of the circle runs through as a function of time. 
   
   
       3 . The tracking system according to  claim 1 , wherein the solar vector rod is mounted so it is rotatable around its attachment point on the circular circumference and is longitudinally displaceable and, in addition, is mounted so it is rotatable in a second bearing point which is not connected to the circle. 
   
   
       4 . The tracking system according to  claim 1 , wherein the diameter of the circle corresponds to the largest possible focal width of the lens in the event of vertical incidence of the solar radiation on the entry plane. 
   
   
       5 . The tracking system according to  claim 3 , wherein the second bearing point of the solar vector rod lies in the point of intersection which the circle directly adjoining below the lens plane forms with the focal plane. 
   
   
       6 . The tracking system according to  claim 1 , wherein the circles comprises circular disks or rotating bars rotatable around their center points, whose diameters or lengths correspond to the maximum focal width. 
   
   
       7 . The tracking system according to  claim 1 , wherein in azimuthal solar direction sensor is located in the end of the solar vector rod facing toward the sun, which provides the control signals for the motorized rotation of the circular disks. 
   
   
       8 . The tracking system according to  claim 1 , wherein an elevation sensor is additionally located at the end of the solar vector rod, which rotates the entire configuration via a motor into the correct elevation as a function of time. 
   
   
       9 . The tracking system according to  claim 1 , wherein either the lens is fixed and the strip-shaped receiver is displaced in the Z and Y axes or vice versa. 
   
   
       10 . The tracking system according to  claim 1 , wherein only the focal width correction is performed via a telescoping tube or an equivalent mechanical configuration by the kinematics of the solar vector rod, while the correction of the focal line offset is performed by lenses extended on the left and right by D/2.