System and Method for Concentrating Sunlight

Abstract

A system for concentrating solar energy is provided. The solar concentrating system uses a membrane formed of a flexible material to form either a reflective or refractive surface of a predefined shape. A quantity of fluid disposed on the membrane deforms the membrane into the predefined shape. In one embodiment the fluid is a liquid and the deformation of the membrane is determined by the mass of fluid and the effect of gravity. In another embodiment, the fluid is a gas and the deformation of the membrane is determined by the pressure of the gas contained in a cavity formed by the membrane on the bottom and a transparent layer forming the top surface of the cavity.

1 . A system for concentrating solar energy, said system comprising:
 a membrane surface constructed of a thin flexible material;   a quantity of fluid having a predefined index of refraction, said quantity of fluid being disposed on a top surface of said membrane surface for deforming said membrane surface into a surface having a predefined cross-section;   a support structure for supporting said membrane surface and said quantity of fluid, said support structure allowing said membrane surface to deform under the influence of said quantity of fluid and gravity.   
     
     
         2 . The system as in  claim 1 , further comprising:
 a solar collecting apparatus for collecting solar energy and converting said solar energy to a second form of energy.   
     
     
         3 . The system as in  claim 2 , wherein said solar collecting apparatus is formed of at least one photovoltaic cell adapted for receiving concentrated solar energy. 
     
     
         4 . The system as in  claim 2 , wherein said solar collecting apparatus is a heat pipe. 
     
     
         5 . The system as in  claim 1 , further comprising:
 a rotating base supporting said support structure; and   a tracking unit for controlling the azimuth of said rotating base to track a movement of a sun across a sky and orient said membrane surface to maximize incidence of said solar energy onto said membrane surface.   
     
     
         6 . The system as in  claim 5 , further comprising an altitude tracking system for adjusting said angle of said membrane surface to maximize incident solar energy. 
     
     
         7 . The system as in  claim 1 , further comprising:
 at least one flat reflective surface positioned remotely of said membrane surface; and   a tracking unit for controlling said position of said at least one flat reflective surface to track a movement of said sun across said sky and orient said flat reflective surface to maximize incidence of said solar energy onto said membrane surface.   
     
     
         8 . The system as in  claim 1 , wherein said membrane surface is reflective of at least a portion of wavelengths of said solar energy. 
     
     
         9 . The system as in  claim 1 , wherein said membrane surface is transparent of at least a portion of wavelengths of said solar energy. 
     
     
         10 . The system as in  claim 1 , further comprising:
 a second membrane surface, transparent to at least a portion of wavelengths of said solar energy, said second membrane surface being disposed above said membrane surface and deformed by a second quantity of fluid; and   a second support structure for supporting said second membrane surface.   
     
     
         11 . The system as in  claim 1 , wherein said fluid is a liquid. 
     
     
         12 . The system as in  claim 1 , further comprising a covering surface formed of transparent material for sealingly holding said quantity of fluid between said membrane surface and said covering surface. 
     
     
         13 . The system as in  claim 12 , wherein said fluid is a gas. 
     
     
         14 . A system for concentrating solar energy onto a heat pipe, comprising:
 an optically transparent top layer;   an optically reflective bottom layer, said bottom layer being a flexible material; and   a frame bonded to said top layer and said bottom layer forming an air-tight cavity therebetween, said cavity being filled with a gas at a predetermined pressure for deforming said bottom layer into an substantial circular arc cross-section.   
     
     
         15 . The system as in  claim 14 , further comprising a dual-axis tracking system for tracking the position of a sun's motion throughout a day. 
     
     
         16 . The system as in  claim 14 , wherein said top layer is a rigid material. 
     
     
         17 . The system as in  claim 14 , wherein said top layer is a flexible material deformable by said gas filling said cavity. 
     
     
         18 . The system as in  claim 14 , further comprising a heat pipe of thermally conductive material and configured for transporting a thermal fluid across said system at a focal position of light reflected by said bottom layer.