Sun tracking solar concentrator

Abstract

A sun tracking solar concentrator includes a one or two-sided linear Fresnel lens imprinted on a rollable sheet that is curved to form as a cylindrical arc surface. A one sided lens has a first zero line or a center point that transmits sunlight through without any refraction. A two sided lens also has a second zero line that is perpendicular to the first zero line. The Fresnel lens may be spooled onto rollers at its two straight ends. The first zero line or the center point may be positioned along the cylindrical arc by rotating one or both of the rollers. This mechanism aimed at providing horizontal tracking of the sun as it moves from East to West. Vertical tracking is accomplished by a tiltable mount coupled to the two rollers.

1 . A sun tracking solar concentrator comprising:
 a Fresnel lens comprising a linear arrangement of prisms with a common non-refracting first zero line, the Fresnel lens being curved to form a substantially cylindrical arc surface such that the non-refracting first zero line is parallel to a cylinder axis; and   a mechanism for positioning the non-refracting first zero line along the cylindrical arc surface and parallel to the axis of the cylinder.   
     
     
         2 . The sun tracking solar concentrator as in  claim 1  wherein the mechanism positions the non-refracting first zero line so that a plane tangent to the cylindrical arc and including the first zero line is substantially perpendicular to incident solar rays. 
     
     
         3 . A sun tracking solar concentrator comprising:
 a Fresnel lens comprising a radial arrangement of prisms with a common non-refracting center point, the Fresnel lens being curved to form a substantially cylindrical arc surface; and   a mechanism for positioning the non-refracting center point on the cylindrical arc surface.   
     
     
         4 . The sun tracking solar concentrator as in  claim 3  wherein the mechanism positions the non-refracting center point so that a plane tangent to the cylindrical arc and including the non-refracting center point line is substantially perpendicular to incident solar rays. 
     
     
         5 . A sun tracking solar concentrator comprising:
 a single sided Fresnel lens comprising a linear arrangement of a chain of prisms with a common non-refracting first zero line, the single sided Fresnel lens being curved to form a substantially cylindrical arc surface such that the non-refracting first zero line is parallel to the cylinder axis; and   a mechanism for orienting the non-refracting first zero line so that a plane tangent to the cylindrical arc and including the first zero line is substantially perpendicular to incident solar rays.   
     
     
         6 . A sun tracking solar concentrator comprising:
 a two sided linear Fresnel lens, comprising a chain of prisms with a common non-refracting first zero line on a first side for concentrating rays of the sun along a first axis and a chain of prisms on a second side for concentrating rays of the sun along a second axis perpendicular to the first axis, the two sided linear Fresnel lens being curved to form a substantially cylindrical arc surface such that the non-refracting first zero line of the first side is parallel to the axis of the cylinder; and   a mechanism for orienting the non-refracting first zero line of the first side so that a plane tangent to the cylindrical arc and including the first zero line is substantially perpendicular to incident solar rays.   
     
     
         7 . The sun tracking solar concentrator as in  claim 6  wherein the first side of Fresnel lens faces inward and the second side faces outward. 
     
     
         8 . The sun tracking solar concentrator as in  claim 6  wherein the Fresnel lens is imprinted on a rollable sheet. 
     
     
         9 . The sun tracking solar concentrator as in  claim 8  wherein the Fresnel lens is spooled onto rollers. 
     
     
         10 . The sun tracking solar concentrator as in  claim 9  wherein the rollers are rotated to position the non-refracting first zero line of the first side along the cylindrical arc. 
     
     
         11 . The sun tracking solar concentrator as in  claim 9  wherein the rollers are tilted to orient the non-refracting first zero line of the first side with respect to the ground. 
     
     
         12 . The sun tracking solar concentrator as in  claim 9  wherein the rollers are coupled to each other and pivot around a common axis to orient the non-refracting first zero line of the first side with respect to the ground. 
     
     
         13 . A sun tracking solar concentrator comprising:
 a linear Fresnel lens imprinted onto a rollable sheet and comprising a chain of prisms with a common non-refracting first zero line on one side of the sheet for concentrating rays of the sun along a single dimension, the linear Fresnel lens being curved to form a substantially cylindrical arc surface such that the non-refracting first zero line of the linear Fresnel lens is parallel to the cylinder axis, and   a pair of rollers onto which the Fresnel lens is spooled, the rollers being configured to rotate to position the non-refracting first zero line.   
     
     
         14 . The sun tracking solar concentrator as in  claim 13  further comprising a tiltable mount coupled to the pair of rollers. 
     
     
         15 . A sun tracking solar concentrator comprising:
 a two sided linear Fresnel lens imprinted onto a rollable sheet and comprising a first chain of prisms with a common non-refracting first zero line on a first side of the sheet for concentrating the rays of the sun along a first axis and a second chain of prisms on a second side of the sheet for concentrating rays of the sun along a second axis perpendicular to the first axis, the two sided linear Fresnel lens being curved to form a substantially cylindrical arc surface such that the non-refracting first zero line of the first chain of prisms is parallel to the cylinder axis; and   a pair of rollers onto which the two sided Fresnel lens is spooled, the rollers being configured to rotate to position the non-refracting first zero line of the first side.   
     
     
         16 . The sun tracking solar concentrator as in  claim 15  further comprising a tiltable mount coupled to the pair of rollers. 
     
     
         17 . The sun tracking solar concentrator as in  claim 15  further comprising at least a pair of ribs configured to curve the two sided Fresnel lens substantially into the cylindrical arc surface. 
     
     
         18 . The sun tracking solar concentrator as in  claim 17  further comprising sprockets traversing along the ribs and coupled into perforations formed along a curved side of the lens, the sprockets maintaining the Fresnel lens in the shape of the cylindrical arc surface under tension. 
     
     
         19 . The sun tracking solar concentrator as in  claim 15  wherein the two sided linear Fresnel lens is cut into at least two strips that run perpendicular to the non-refracting first zero line of the first side and each strip is spooled onto a pair of rollers. 
     
     
         20 . The sun tracking solar concentrator as in  claim 19  further comprising at least three ribs configured to curve the strips substantially into the cylindrical arc surface. 
     
     
         21 . The sun tracking solar concentrator as in  claim 20  further comprising sprockets traversing along the ribs and coupled into perforations formed along curved sides of the strips, the sprockets maintaining the strips in the shape of the cylindrical arc surface under tension.