Spherical Heliostat

• US 20090183730A1
• Filed: 01/18/2008
• Published: 07/23/2009
• Est. Priority Date: 01/18/2008
• Status: Active Grant

• Current Assignee: Laird Knight
• Original Assignee: Laird Knight
• Inventors: Knight, Laird
• Granted Patent: US 7,887,188 B2
• Time in Patent Office: Days
• US Class Current: 126/578
• CPC Class Codes: F24S 25/00 Arrangement of stationary mountings or supports for solar heat collector modules
• CPC Class Codes: F24S 30/40 for rotary movement
• CPC Class Codes: F24S 50/20 for tracking
• CPC Class Codes: F24S 80/525 made of plastics
• CPC Class Codes: F24S 80/58 characterised by their mountings or fixing means
• CPC Class Codes: H01L 31/0547 comprising light concentrating means of the reflecting type, e.g. parabolic mirrors, concentrators using total internal reflection
• CPC Class Codes: Y02E 10/47 Mountings or tracking
• CPC Class Codes: Y02E 10/52 PV systems with concentrators

Abstract

A heliostat for the collection of solar energy while resting on a surface is disclosed, comprising a rigid disk having an exposed surface, a back surface, and a circular peripheral edge connecting the exposed surface to the back surface. The peripheral edge includes a plurality of wheels each having a rotational axis substantially tangent to the circular peripheral edge of the disk. Each wheel is driven by an electric motor electrically connected to a power source. A hollow, substantially transparent spherical enclosure contains the rigid disk. Each wheel of the disk frictionally engages an inner surface of the enclosure such that rotation of the any of the wheels changes the orientation of the disk within the enclosure. A control circuit is electrically disposed between the power source and each motor. The control circuit includes a direction setting means for causing the motors to orient the exposed surface substantially facing a commanded direction. A rigid frame is included for supporting the enclosure and disk on the surface.

Claims

1. A heliostat for the collection of electromagnetic energy while resting on a surface, comprising:

a rigid disk having an exposed surface, a back surface, and a circular peripheral edge connecting the exposed surface to the back surface, the peripheral edge including a plurality of wheels each having a rotational axis substantially tangent to the circular peripheral edge of the disk, at least two of such wheels driven by an electric motor electrically connected to a power source fixed to the disk;

a hollow, substantially transparent spherical enclosure containing the rigid disk, each wheel of the disk frictionally engaging an inner surface of the enclosure such that rotation of the any of the wheels changes the orientation of the disk within the enclosure;

a control circuit electrically disposed between the power source and each motor, the control circuit including a direction setting means for causing the motors to orient the exposed surface towards a commanded direction; and

a rigid frame for supporting the enclosure and disk on the surface.

2. The heliostat of claim 1 wherein the exposed surface of the disk is substantially flat.

3. The heliostat of claim 2 wherein the exposed surface further includes a plurality of photovoltaic cells electrically connected to at least one power cable traversing the spherical enclosure.

4. The heliostat of claim 1 wherein the exposed surface is concave and includes a reflective coating.

5. The heliostat of claim 1 wherein each of the wheels includes a high-friction outer surface for making frictionally immobile contact with the inner surface of the enclosure.

6. The heliostat of claim 1 wherein the power source is a battery, the battery charged by at least one photovoltaic cell fixed to the exposed surface.

7. The heliostat of claim 3 wherein the power source is the plurality of photovoltaic cells.

8. The heliostat of claim 1 wherein the enclosure is comprised of a substantially rigid transparent material.

9. The heliostat of claim 1 wherein the enclosure is comprised of a flexible substantially air-impervious material such that the enclosure may be inflated, and further includes an inflating means.

10. The heliostat of claim 9 wherein the inflating means is an air pump electrically connected to the power source and adapted to pump air into the enclosure from outside thereof.

11. The heliostat of claim 8 wherein the spherical enclosure is two hemispheres selectively fixed together at an equator by a sealing means.

12. The heliostat of claim 3 wherein the direction setting means of the control circuit includes a voltage measuring means, whereby the control circuit periodically varies the orientation of the exposed surface to find the orientation resulting in the maximum output voltage of the plurality of photovoltaic cells.

13. The heliostat of claim 1 wherein the direction setting means of the control circuit includes a level sensing means, a compass, a clock means, a calendar means, and a preset location memory, whereby the control circuit calculates the position of the sun relative to the location of the heliostat on earth, the time and date, the direction generally orthogonal to the exposed surface of the disk, and an inclination angle of the disk as measured by the level sensing means, in order to set the commanded direction of the exposed surface of the disk relative to the position of the sun.

14. The heliostat of claim 1 wherein the control circuit includes a wireless transceiver for receiving the commanded direction from a master control circuit.

15. The heliostat of claim 1 wherein the rigid frame includes a supporting ring into which the spherical enclosure sits stationary by gravity and friction.

16. The heliostat of claim 15 the rigid frame includes a plurality of legs for supporting the ring and enclosure above the surface.

17. The heliostat of claim 16 further including a plurality of stakes, each for fixing one leg immovably to the surface.

18. The heliostat of claim 1 wherein the power source is at least one power cable traversing the spherical enclosure.

19. The heliostat of claim 1 wherein the control circuit traverses the spherical enclosure.