Thermal-mechanical positioning for radiation tracking

• US 8,499,756 B2
• Filed: 04/30/2010
• Issued: 08/06/2013
• Est. Priority Date: 04/30/2009
• Status: Active Grant

• Current Assignee: Sunpoint Technologies Incorporated
• Original Assignee: Sunpoint Technologies Incorporated
• Inventors: Bathurst, Stephen P., Carvey, Andrew W., Cohen, Eric D., Etra, Jordan V., Liau, Forrest W., Whitfield, George C.
• Primary Examiner(s): Rinehart, Kenneth
• Assistant Examiner(s): PEREIRO, JORGE ANDRES
• Application Number:
  US12/771,788
• Publication Number:
  US 20100275904A1
• Time in Patent Office: 1,194 Days
• Field of Search: 126/600, 126/571, 126/572, 126/573, 126/580, 126/581, 126/604
• US Class Current: 126/581
• CPC Class Codes: F24S 2020/23 movable or adjustable
• CPC Class Codes: F24S 2030/11 Driving means
• CPC Class Codes: F24S 2030/133 in the form of flexible elements, e.g. belts, chains, ropes
• CPC Class Codes: F24S 30/425 Horizontal axis
• CPC Class Codes: F24S 40/85 Arrangements for protecting solar collectors against adverse weather conditions F24S40/10 takes precedence
• CPC Class Codes: F24S 50/00 Arrangements for controlling solar heat collectors
• CPC Class Codes: F24S 50/20 for tracking
• CPC Class Codes: F24S 50/40 responsive to temperature
• CPC Class Codes: F24S 50/60 responsive to wind
• CPC Class Codes: F24S 80/56 characterised by means for preventing heat loss
• CPC Class Codes: H02S 20/00 Supporting structures for PV modules
• CPC Class Codes: H02S 20/32 specially adapted for solar tracking
• CPC Class Codes: Y02E 10/47 Mountings or tracking
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy

Abstract

The invention relates to systems and methods for controlling angular position of a pivotable platform relative to a radiation source. In one embodiment, an apparatus for controlling angular position of a pivotable platform relative to a radiation source includes a frame, a thermal actuation element coupled to the frame, a pivotable platform positioned between the radiation source and the thermal actuation element so as to at least partially block energy from the radiation source from impinging on the thermal actuation element, and apparatus for pivoting the pivotable platform in response to a thermally controlled deformation of the thermal actuation element.

Claims

1. A system for controlling angular position of a pivotable platform relative to a radiation source, the system comprising:

a frame;

a platform pivotably coupled to the frame;

a thermal actuation element coupled to the frame and adapted to pivot the platform to substantially track a movement of the radiation source, wherein the pivotable platform is adapted to at least partially block energy from the radiation source from impinging on the thermal actuation element; and

means for dampening disturbances to the pivotable platform selected from the group consisting of a wind shield, an airfoil, a wind activated braking mechanism, and combinations thereof.

2. The system of claim 1, wherein a surface area of the thermal actuation element that the pivotable platform blocks from the radiation source is dependent upon at least one of a position of the radiation source and an angle of the platform.

3. The system of claim 1, wherein the thermal actuation element is coupled at a distal end to a means for pivoting the platform.

4. The system of claim 1, wherein the thermal actuation element is coupled at a proximal end to the frame by a mounting structure.

5. The system of claim 1, wherein the thermal actuation element comprises a substantially elongate bimetallic element.

6. The system of claim 1, comprising a plurality of thermal actuation elements.

7. The system of claim 1, comprising two thermal actuation elements arranged substantially symmetrically about a pivot axis of the platform.

8. A system for controlling angular position of a pivotable platform relative to a radiation source, the system comprising:

a frame;

a platform pivotably coupled to the frame;

a thermal actuation element coupled to the frame and adapted to pivot the platform to substantially track a movement of the radiation source, wherein the pivotable platform is adapted to at least partially block energy from the radiation source from impinging on the thermal actuation element; and

means for controlling convective heat loss from the thermal actuation element comprising an enclosure adapted to permit transmission of energy from the radiation source to the thermal actuation element while controlling air flow proximate the thermal actuation element, and wherein the enclosure comprises a shutter adapted to control the air flow.

9. The system of claim 8, wherein a surface area of the thermal actuation element that the pivotable platform blocks from the radiation source is dependent upon at least one of a position of the radiation source and an angle of the platform.

10. The system of claim 8, wherein the thermal actuation element is coupled at a distal end to a means for pivoting the platform.

11. The system of claim 8, wherein the thermal actuation element is coupled at a proximal end to the frame by a mounting structure.

12. The system of claim 8, wherein the thermal actuation element comprises a substantially elongate bimetallic element.

13. The system of claim 12, wherein the bimetallic element comprises a plurality of leaves held together by at least one clamping and fastening mechanism that maintains physical contact between adjacent leaves during thermally controlled deformation of the bimetallic element, the clamping and fastening mechanism permitting adjacent leaves to slide substantially freely against one another in an axial direction while remaining in physical contact.

14. The system of claim 8, comprising a plurality of thermal actuation elements.

15. The system of claim 14, wherein at least two of the plurality of thermal actuation elements are arranged in parallel.

16. The system of claim 8, comprising two thermal actuation elements arranged substantially symmetrically about a pivot axis of the platform.

17. The system of claim 8, wherein the thermal actuation element comprises two separate elongate elements coupled at a proximal end to the frame, at least one of the elongate elements adapted for temperature induced linear expansion.

18. The system of claim 17, wherein the two elongate elements are coupled to the means for pivoting the pivotable platform through a hinge element.

19. The system of claim 8, wherein the thermal actuation element is coupled to the platform through a coupling element selected from the group consisting of at least one gear, rod, cable, pivoting shaft, cam, and combinations thereof.

20. The system of claim 19, wherein the cable is wrapped around a pivotable shaft coupled to the pivotable platform.