Energy collector system having east-west extending linear reflectors

Abstract

Disclosed herein are examples and variations of solar energy collector systems comprising an elevated linear receiver extending generally in an east-west direction, a polar reflector field located on the polar side of the receiver, and an equatorial reflector field located on the equatorial side of the receiver. Each reflector field comprises reflectors positioned in parallel rows which extend generally in the east-west direction. The reflectors in each field are arranged and positioned to reflect incident solar radiation to the receiver during diurnal east-west processing of the sun and pivotally driven to maintain reflection of the incident solar radiation to the receiver during cyclic diurnal north-south processing of the sun. Inter-row spacings of the reflectors on opposite sides of the receiver may be asymmetrical.

1 . A solar energy collector system comprising:
 an elevated linear receiver extending generally in an east-west direction;   a polar reflector field located on the polar side of the receiver; and   an equatorial reflector field located on the equatorial side of the receiver;   wherein each reflector field comprises reflectors positioned in parallel side-by-side rows which extend generally in the east-west direction, the reflectors in each field are arranged and positioned to reflect incident solar radiation to the receiver during diurnal east-west processing of the sun and pivotally driven to maintain reflection of the incident solar radiation to the receiver during cyclic diurnal north-south processing of the sun, and inter-row spacings of the reflectors on opposite sides of the receiver are asymmetrical.   
     
     
         2 . The solar energy collector system of  claim 1  wherein inter-row spacings in the equatorial reflector field are smaller than corresponding inter-row spacings in the polar reflector field. 
     
     
         3 . The solar energy collector system of  claim 1 , wherein reflectors in the equatorial reflector field are located closer to the receiver than are corresponding reflectors in the polar reflector field. 
     
     
         4 . The solar energy collector system of  claim 1 , wherein the reflector to ground area ratio is greater than about 70%. 
     
     
         5 . The solar energy collector system of  claim 1 , wherein the reflector to ground area ratio is approximately 80%. 
     
     
         6 . The solar energy collector system of  claim 1 , wherein solar radiation reflected to the receiver heats a working or heat exchange fluid. 
     
     
         7 . The solar energy collector system of  claim 6 , wherein the working or heat exchange fluid comprises water. 
     
     
         8 . The solar energy collector system of  claim 1 , wherein the receiver comprises an inverted trough having a substantially horizontal aperture through which solar radiation reflected by the reflectors may pass. 
     
     
         9 . The solar energy collector system of  claim 8 , wherein the inverted trough comprises a plurality of absorber tubes that are arranged side by side, each absorber tube having a diameter small relative to the aperture of the trough and, in use, carrying a working or heat exchange fluid. 
     
     
         10 . The solar energy collector system of  claim 9 , wherein the ratio of each absorber tube diameter to the trough aperture is in the range of 0.01:1.00 to 0.10:1.00. 
     
     
         11 . The solar energy collector system of  claim 9 , wherein the trough comprises from about 10 to about 30 of the absorber tubes. 
     
     
         12 . The solar energy collector system of  claim 9 , wherein the working or heat exchange fluid comprises water. 
     
     
         13 . The solar energy collector system of  claim 9 , wherein the absorber tubes are configured such that, in use, working or heat exchange fluid flows through the absorber tubes in parallel streams in a common direction. 
     
     
         14 . The solar energy collector system of  claim 9 , wherein the absorber tubes are configured such that, in use, in-flowing working or heat exchange fluid is first directed through outer ones of the absorber tubes and then directed through inner ones of the absorber tubes. 
     
     
         15 . The solar energy collector system of  claim 9 , wherein the absorber tubes are freely supported by rotating cylindrical supports. 
     
     
         16 . The solar energy collector system of  claim 8 , wherein the aperture is closed with a cover that is substantially transparent to solar radiation. 
     
     
         17 . The solar energy collector system of  claim 1 , wherein a reflector has a radius of curvature of about 20 to about 50 meters. 
     
     
         18 . The solar energy collector system of  claim 1 , wherein a reflector comprises:
 a reflector element; and   a carrier structure including a platform that supports the reflector element and hoop-like end members between which the platform extends, the hoop-like end members having a diameter greater than a width of the reflector element and accommodating rotation of the carrier structure about an axis of rotation that is substantially coincident with a longitudinal axis of the reflector element.   
     
     
         19 . The solar energy collector system of  claim 18 , wherein the reflector element has a radius of curvature of about 20 to about 50 meters. 
     
     
         20 . The solar energy collector system of  claim 18 , wherein the reflector element is secured to the platform in a manner such that a curvature of the platform is imparted to the reflector element. 
     
     
         21 . The solar energy collector system of  claim 1 , wherein the receiver has a length of about 300 to about 600 meters. 
     
     
         22 . The solar energy collector system of  claim 1 , wherein the linear receiver is one of a plurality of linear receivers arranged side-by-side and spaced apart by about 30 to about 35 meters. 
     
     
         23 . The solar energy collector system of  claim 1 , wherein a row of reflectors has a length of about 300 to about 600 meters. 
     
     
         24 . The solar energy collector system of  claim 1 , wherein the reflector fields are located at ground level. 
     
     
         25 . The solar energy collector system of  claim 1 , wherein the equatorial and polar reflector fields include the same number of rows of reflectors. 
     
     
         26 . The solar energy collector system of  claim 1 , wherein the equatorial reflector field includes more rows of reflectors than does the polar reflector field. 
     
     
         27 . A method of making a solar energy system comprising:
 positioning and arranging rows of reflectors on a polar side of an elevated generally east-west extending linear receiver to reflect solar radiation to the receiver; and   positioning and arranging rows of reflectors on an equatorial side of the receiver to reflect solar radiation to the receiver with spacings between rows on the equatorial side of the receiver smaller than spacings between corresponding rows on the polar side of the receiver.   
     
     
         28 . The method of  claim 27 , further comprising positioning rows on the equatorial side of the receiver closer to the receiver than corresponding rows on the polar side of the receiver. 
     
     
         29 . The method of  claim 27 , further comprising configuring the reflectors to be pivotally driven to maintain reflection of solar radiation to the receiver during diurnal north-south processing of the sun. 
     
     
         30 . The method of  claim 27 , further comprising arranging a plurality of absorber tubes side-by-side in an inverted trough in the receiver to absorb light reflected by the reflectors and thereby heat a working or heat exchange fluid that, in use, flows through the absorber tubes, the trough having an aperture through which solar radiation reflected by the reflectors may pass to be incident on the absorber tubes. 
     
     
         31 . The method of  claim 30 , wherein the aperture is substantially horizontal. 
     
     
         32 . The method of  claim 30 , wherein the absorber tubes have a diameter that is small relative to the aperture of the trough. 
     
     
         33 . The method of  claim 32 , wherein the ratio of the absorber tube diameter to the trough aperture is in the range of 0.01:1 to 0.10:1. 
     
     
         34 . The method of  claim 30 , wherein the trough comprises about 10 to about 30 of the absorber tubes arranged side-by-side. 
     
     
         35 . The method of  claim 30 , further comprising closing the aperture with a cover that is substantially transparent to solar radiation. 
     
     
         36 . The method of  claim 30 , further comprising configuring the absorber tubes such that, in use, working or heat exchange fluid flows through the absorber tubes in parallel streams in a common direction. 
     
     
         37 . The method of  claim 30 , further comprising configuring the absorber tubes such that, in use, in-flowing working or heat exchange fluid is first directed through outer ones of the absorber tubes and then directed through inner ones of the absorber tubes. 
     
     
         38 . The method of  claim 27 , wherein a reflector has a radius of curvature of about 20 to about 50 meters. 
     
     
         39 . The method of  claim 27 , wherein the receiver has a length of about 300 to about 600 meters. 
     
     
         40 . The method of  claim 27 , wherein a row of reflectors has a length of about 300 to about 600 meters.