Cylindrical radiant energy direction device with refractive medium

A device for collecting and concentrating solar energy incident on an entrance onto the surface of an energy absorber where said absorber surface is of less area than said entrance surface, the entrance surface being on a first side of a first reference axis, the absorber surface having a cross section bounded by and which is convex with respect to the first reference axis on said first side of said first reference axis, the absorber surface having a second reference axis extending therethrough perpendicular to said first reference axis, the perimeter of the cross section of the absorber surface extending from a first edge point along the first reference axis to a second edge point along the first reference axis, comprising:

• a refractive element and a first reflective boundary, said boundary and said element being positioned on said first side of said first reference axis between the absorber and entrance surface such that extremal rays from a source of solar energy incident on the entrance surface at an angle with respect to said second reference axis equal to or less than a predetermined value are refracted unequally by said refractive element, said first reflective boundary being of such contour that the slope of any point along said contour is the maximum slope consistent with achieving reflection of any extremal ray of energy incident on said entrance surface and then refracted and incident on said point of said boundary along a line which intersects the perimeter of the cross section of the absorber surface at an angle not exceeding a particular value C where C is less than or equal to 90.degree., said reflective boundary extending from said first edge point of said absorber to no further than an intersection with said entrance surface, said boundary and said absorber being parallel to a third reference axis perpendicular to said first and second reference axis to form a trough-shaped device.