Radiant energy collector

• US 4,002,499 A
• Filed: 07/26/1974
• Issued: 01/11/1977
• Est. Priority Date: 07/26/1974
• Status: Expired due to Term

• Current Assignee: The United States of America as represented by the United States Energy Research and Development Administration
• Original Assignee: The United States of America as represented by the United States Energy Research and Development Administration
• Inventors: Winston, Roland
• Primary Examiner(s): Moskowitz, Nelson
• Application Number:
  US05/492,074
• Time in Patent Office: 900 Days
• Field of Search: 250/228, 250/216, 240/103 B, 240/1.3, 136/206, 136/214
• US Class Current: 136/206
• CPC Class Codes: F24S 2023/838 involutes
• CPC Class Codes: F24S 23/80 having discontinuous faces
• CPC Class Codes: G02B 19/0023 at least one surface having optical power
• CPC Class Codes: G02B 19/0042 for use with direct solar radiation
• CPC Class Codes: G02B 19/0076 for use with a detector G02B19/009, G02B19/0095 take precedence
• CPC Class Codes: G02B 5/10 with curved faces
• CPC Class Codes: Y02E 10/40 Solar thermal energy, e.g. solar towers

Abstract

An electromagnetic energy collection device is provided which does not require a solar tracking capability. It includes an energy receiver positioned between two side walls which reflect substantially all incident energy received over a predetermined included angle directly onto the energy receiver.

Claims

1. A radiant energy concentration device, comprising, an energy receiver positioned tangent to a reference plane, said energy receiver having a first reference axis extending therethrough, with said first reference axis being perpendicular to said reference plane so that said energy receiver extends along said first reference axis away from said reference plane, a first side wall for directing radiant energy positioned on a first side of said energy receiver and having first and second portions, said second portion of said first side wall having the shape of the involute of said first side of said energy receiver and extending from a point of tangency of said energy receiver to said reference plane to a first shadow line of said energy receiver, said first shadow line being defined as the line which crosses said first reference axis at a point on the same side of said reference plane as said energy receiver at an angle θ

₁ max and further which is tangent to said energy receiver on the same side of said first reference axis as said first side wall, said first portion of said first side wall being an extension of said second portion of said first side wall and extending from said first shadow line to no further than a first terminal point, θ

₁ max thereby being the maximum angle from said first reference axis at which all radiation energy crossing said first reference axis at an angle equal to or less than θ

₁ max is directed into said energy receiver by said first side wall, said first portion of said first side wall being shaped so that all radiant energy crossing said first reference axis at said angle θ

₁ max and striking any point on said first portion of said first side wall is directed along a line tangent to said energy receiver, said first terminal point being the point wherein with said first portion of said first side wall extending to said first terminal point a tangent to said first side wall at said first terminal point is parallel to said first reference axis.

2. The device of claim 1 wherein said device is a radiant energy concentration device and said energy transducer is an energy receiver.

3. The radiant energy concentration device of claim 2 further comprising, a second side wall for directing radiant energy into said energy receiver and positioned on a second side of said energy receiver substantially opposite said first side and having first and second portions, said second portion of said second side wall having the shape of the involute of said second side of said energy receiver and extending from a point of tangency of said energy receiver to said reference plane to a second shadow line of said energy receiver, said second shadow line being defined as the line which crosses said first reference axis at a point on the same side of said reference plane as said energy receiver at an angle θ

₂ max and further which is tangent to said energy receiver on the same side of said first reference axis as said second side wall, θ

₂ max being the maximum angle from said first reference axis at which all radiant energy crossing said first reference axis at an angle equal to or less then θ

₂ max is directed into said energy receiver by said second side wall, said first portion of said second side wall being an extension of said second portion of said second side wall and extending from said second shadow line to no further than a second terminal point, said first portion of said second side wall being shaped so that all radiant energy crossing said first reference axis at said angle θ

₂ max and striking any point on said first portion of said second side wall is directed along a line tangent to said energy receiver, said second terminal point being the point wherein with said first portion of said second side wall extending to said second terminal point a tangent thereto is parallel to said first reference axis.

4. The device of claim 3 wherein said first portions of said first and second side walls extend to said first and second terminal points respectively.

5. The radiant energy concentration device of claim 4 wherein θ

₂ max is different from θ

₁ max and further including a mirror positioned on said first reference axis and extending along said first reference axis to a point no less than the height of the longer of said first and second side walls, said mirror having opposing reflective sides facing said first and second side walls.

6. The radiant energy concentration device of claim 4 wherein θ

₁ max equals θ

₂ max.

7. The radiant energy concentration device of claim 6 wherein the cross section of said energy receiver is in the shape of a circle with a diameter thereof extending along said first reference axis.

8. The radiant energy concentration device of claim 6 wherein the cross section of said energy receiver is in the shape of an oval which has an axis of symmetry extending along said first reference axis.

9. The radiant energy concentration device of claim 6 wherein said energy receiver extends along a second reference axis parallel to said reference plane, said first and second side walls also extending in the direction of said second axis and being parallel thereto to form a trough-shaped structure.

10. The radiant energy concentration device of claim 9 wherein said energy receiver is in the form of a flat sheet having a longitudinal axis extending along said second reference axis with said flat sheet being disposed symmetrically with respect to said first reference axis.

11. The radiant energy concentration device of claim 9 wherein said energy receiver is in the form of a flat sheet and having a longitudinal axis extending along said second reference axis and a transverse axis extending along said first reference axis whereby a first side of said flat sheet is opposite said first side wall and a second side of said flat sheet is opposite said second side wall.

12. The radiant energy concentration device of claim 11 wherein said energy collector includes photovoltaic cells positioned on said first and second sides of said flat sheet energy receiver for receiving radiant energy.

13. The radiant energy concentration device of claim 9 and further including a pair of opposing end walls joining said first and second side walls with said end walls being perpendicular to said reference plane.

14. The radiant energy concentration device of claim 9 wherein said first and second side walls are formed of a material for reflecting substantially all solar radiation directed thereon.

15. The radiant energy concentration device of claim 14 wherein said energy receiver is in the form of a heat pipe.

16. The radiant energy concentration device of claim 15 wherein said heat pipe is in the form of a tube having a circular cross section with a diameter of said tube extending along said first reference axis and the longitudinal axis of said tube extending along said second reference axis.

17. The radiant energy concentration device of claim 15 wherein said heat pipe is in the form of a tube having a symmetrical oval cross section with an axis of symmetry of said oval tube extending along said first reference axis and the longitudinal axis of said tube extending along said second reference axis.