Conversion of solar energy to electrical and/or heat energy

Abstract

A parabolic primary mirror ( 10 ) has a concave specular surface ( 12 ) that is constructed and positioned to receive solar energy and focus it towards a focal point. A secondary mirror ( 14 ) having a convex specular surface ( 16 ) is constructed and positioned to receive focused solar energy from the primary mirror and focus it onto an annular receiver ( 18 ). The annular receiver ( 18 ) may include an annular array of optical elements ( 100 ) constructed to receive solar energy from the secondary specular surface ( 14 ) and focus it onto a ring of discrete areas. A ring of solar-to-electrical conversion units are positioned on the ring of discrete areas.

1 . A mirror, comprising:
 a thin metal body having a curved specular surface;   a polymer layer on the specular surface;   a reflective metal layer on the polymer layer; and   a thin glass layer on the metal layer.   
     
     
         2 . The mirror of  claim 1 , wherein the thin metal body is formed from an aluminum alloy. 
     
     
         3 . The mirror of  claim 1 , wherein the thin metal body is formed from a sheet of an aluminum alloy or other metals such as magnesium, titanium or stainless steel. 
     
     
         4 . The mirror of  claim 1 , wherein the curved specular surface is a concave surface. 
     
     
         5 . The mirror of  claim 4 , wherein the concave surface is a substantially parabolic surface. 
     
     
         6 . The mirror of  claim 4 , wherein the curved specular surface is a convex surface. 
     
     
         7 . The mirror of  claim 6 , wherein the convex surface is a generally hyperbolic surface. 
     
     
         8 . A mirror, comprising:
 a metal body formed to be convex on one side and concave on an opposing side, the body having a specular surface on at least one side;   a polymer layer on the specular surface;   a reflective metal layer on the polymer layer; and   a thin glass layer on the metal layer.   
     
     
         9 . The mirror of  claim 8 , wherein the body is formed from sheet aluminum alloy or other suitable metals such as magnesium, titanium or stainless steel. 
     
     
         10 . The mirror of  claim 9 , wherein the sheet aluminum alloy comprises an age-hardenable aluminum alloy. 
     
     
         11 . The mirror of  claim 8 , wherein the specular surface is disposed on the concave side of the body. 
     
     
         12 . The mirror of  claim 11 , wherein the specular surface is a parabolic surface. 
     
     
         13 . The mirror of  claim 8 , wherein the specular surface is disposed on the convex side of the body. 
     
     
         14 . The mirror of  claim 13 , wherein the specular surface is a hyperbolic surface. 
     
     
         15 . The mirror of  claim 14 , wherein the hyperbolic surface is configured to reflect and focus energy received by the hyperbolic surface onto an annular focus area. 
     
     
         16 . A method of forming a mirror having a convex specular surface configured to focus light energy onto an annular area, comprising:
 providing a hyperbolic curve formed symmetrically about an axis and having a concave side, a convex side, an imaginary focus point on the concave side and a real focus point on the convex side;   tilting the axis and the hyperbolic curve about the imaginary focus point, so that, when tilted, the axis is angularly displaced from its original position by an acute angle and the hyperbolic curve is tilted from its original position;   rotating the portion of the tilted hyperbolic curve that extends from the original axis to the tilted axis and beyond the tilted axis, about the original axis, so that the rotated portion of the tilted hyperbolic curve forms a surface of revolution about the original axis; and   providing the convex specular surface of the mirror with the shape of the surface of revolution so that the specular surface will have an annular focus.   
     
     
         17 . The method of  claim 16 , wherein providing the convex specular surface comprises applying a polymer to the convex specular surface. 
     
     
         18 . The method of  claim 16 , wherein providing the convex specular surface comprises depositing a metal reflective layer on the convex specular surface. 
     
     
         19 . The method of  claim 16 , wherein providing the convex specular surface comprises depositing a glass protective layer on the convex specular surface. 
     
     
         20 . A method of forming a concave mirror, comprising:
 elevating a temperature of a sheet material to a predetermined temperature;   providing a die having a predetermined concave shape;   positioning the sheet material on the die; and   applying a gas at an elevated pressure to a side of the sheet opposite the concave shape to impress the sheet material into conformity with the predetermined concave shape.