SOUTHERLY TILTED SOLAR TRACKING SYSTEM AND METHOD

Abstract

A solar tracking system and method are provided.

Description

PRIORITY CLAIMS

This application claims the benefit under 35 USC 119(e) to and claims priority under 35 USC 120 to U.S. Provisional Patent Application Ser. No. 60/989,434, filed on Nov. 20, 2007 and entitled “Southerly Tilted Solar Tracking System and Method”, the entirety of which is incorporated herein by reference.

FIELD

A solar tracking system and method are provided.

BACKGROUND

Solar tracking systems and methods exist. However, these solar tracking systems are single-axis tracking systems that are not tilted southerly. Therefore, in sunny locations, these conventional single axis solar tracking systems lose some amount of energy due to the fact that the solar tracking system is not tilted. Thus, it is desirable to provide a southerly tilted solar tracking system and method and it is to this end that the system and method are directed. In the southern hemisphere the tracking system would be tilted to the north.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of an embodiment of a portion of a southerly tilted solar tracking system;

FIGS. 2A-2C illustrates details of particular portions of the southerly tilted solar tracking system;

FIG. 3 illustrates an example of an embodiment of a solar energy collection facility that may incorporate the southerly tilted solar tracking system shown in FIGS. 1 and 2A-2C;

FIGS. 4A and 4B illustrate more details of two embodiments of the coupling mechanism associated with each solar panel; and

FIG. 5 illustrates an example of another embodiment of a portion of a southerly tilted solar tracking system.

DETAILED DESCRIPTION OF ONE OR MORE EMBODIMENTS

The system and method are particularly applicable to the solar energy collection facility described below with the particular southerly tilted solar tracking system having the particular components and elements described below and it is in this context that the southerly tilted solar tracking system and method will be described. It will be appreciated, however, that the southerly tilted solar tracking system and method has greater utility since it can be implemented using different components/elements that those shown in the embodiment below and may be implemented in various different solar type systems.

A southerly tilted solar energy collection facility includes a plurality of southerly tilted solar panels configured on an east-west row but with single axis tracking that allows each of the panels to rotate about a north-south axis to follow the sun from sunrise to sunset as shown in FIG. 3. The solar panels in the facility as shown in FIG. 3 are also spaced apart in the east-west direction, such that when each solar panel is tilted, the shadow from one panel does not fall on an adjacent panel and thus reduce the solar energy collecting capabilities of that solar panel.

Each solar panel may further include a unique coupling element to translate linear motion into rotational motion required to accurately track the sun. A lever arm extends from each of the southerly tilted solar panels to linear moving rod or linkage. The lever arm is coupled to the rod using a simple sleeve bearing, such that in the morning and afternoon the effective lever arm is maximum and at noon time the lever arm is shortest. In this system, only the horizontal forces of the load (force required to move the panels from “at rest” and in high wind conditions) are translated to the linear actuator. In addition, the forces transferred to the linear actuator are further reduced in “high wind” conditions due to the longer effective lever-arm during morning and afternoon time periods. The system is an improvement over conventional single-axis tracking systems that are not tilted southerly. In sunny locations, tilting the panels while tracking the sun will provide up to 6% more energy annually when compared to tracking without tilting.

FIG. 1 illustrates an example of an embodiment of a portion of a southerly tilted solar tracking system 200 that includes a first solar panel 10 mounted on a first tilted torque tube 12 oriented on a north-south axis and a second solar panel 20 mounted on a second tilted torque tube 22 oriented on a north-south axis. Each tilted torque tube solar panel assembly is supported by two torque tube bearings 13A, 13B for panel assembly 10 and two torque tube bearings 23A, 23B for panel assembly 20 and a pair vertical support piers 14A, 14B for panel assembly 10 and a pair vertical support piers 24A and 24B for panel assembly 20, with one pier on the north and one pier on the south for each solar panel assembly. The north support piers 14A, 24A may be founded on a horizontal beam 52 perpendicular to the torque tube axis and the south support piers 14B, 24B may be mounted on a horizontal beam 51 perpendicular to the torque tube axis. In one embodiment, the distance between the horizontal beams 51, 52 may be from six to twelve feet.

Each horizontal beam 51, 52 is supported by a pair of vertical piers (61, 63 for the southern horizontal beam and 62, 64 for the northern horizontal beam) wherein the vertical piers are anchored to the earth or another surface. Each solar panel assembly 10, 20 may include a lever arm 71, 72 respectively, wherein each level arm extends from each torque tube and couples to a horizontal drive element 80 supported by a set of linear bearings 91-94 attached to the southern horizontal beam 51. Each lever arm 71, 72 is also attached to the torque tube 12, 22 at a pivot 100 such that the lever arm is not required to be perpendicular to the torque tube. The coupling of each lever arm 71, 72 to the drive element is such that pure horizontal motion of the drive element 80 translates to rotational motion of the lever arm 71,72 that causes each solar panel assembly 10, 20 to rotate about its respective torque tube and to move in unison to follow the sun through the sky throughout the day. The dynamic coupling is achieved through a gimbal and sleeve bearing 110, 111 or a rod and pin arrangement as detailed in copending and co-owned U.S. patent application Ser. No. 11/199,442 which is incorporated herein by reference. In one embodiment, the solar tracking assembly the north horizontal beam 52 may have a taller height than the southern horizontal beam 51 such that the angle measured from a level north-south line to the axis of rotation of the torque tubes is between 15 to 30 degrees.

FIGS. 2A-2C illustrates details of particular portions of the southerly tilted solar tracking system. The solar tracking system shown in FIGS. 2A-2C has a linear actuator 12 fixed to the south horizontal beam at one of the vertical piers supporting the beam and anchored to the earth or other surface. The solar tracking assembly where the linear actuator 12 (such as a linear drive jack) drives a linear drive element on the right and simultaneously drives a linear drive element on the left, such that motion of the single linear actuator causes right and left drive elements to move in unison and causes the dynamically coupled lever arms to rotate the attached torque tubes with solar panels to follow the sun from east to west in the sky throughout the day.

The portions of the solar tracking assembly shown in FIGS. 1-2C above can be combined together as multiple segments added to the left and to the right sides of the linear actuator to increase the number of dynamically coupled lever arms, torque tubes and solar panels to the right and the left sides of the linear actuator. In one embodiment, the additional assemblies will add two hundred to three hundred feet to the left and to the right (east and west respectively) such that the length of the entire row of solar panels may be 400 to 600 feet in length.

FIG. 3 illustrates an example of an embodiment of a solar energy collection facility that may incorporate the southerly tilted solar tracking system shown in FIGS. 1 and 2A-2C. In this facility, a single linear actuator (located at the center portion of a row of solar panels as shown in FIG. 3) activates and controls the motion of this row of solar panels. In the example shown in FIG. 3, a solar energy collection facility with 400 solar panel assemblies (10 rows or 40 solar panel assemblies) is possible while using ten linear actuators. Thus, there are multiple east-west rows (ten in the example in FIG. 3) installed to form an array of such rows, spaced apart in the north-south direction such that the shadow cast from the sun from one south row solar panels does not fall on the adjacent north row panels between the hours of 9 AM to 3 PM on the winter solstice.

FIGS. 4A and 4B illustrate a gimbal sleeve coupling and a pin and slot coupling, respectively, that dynamically couple the solar panel and torque tube to the linear drive element 80. Each of these coupling mechanisms, when an undesirable force is applied to the solar panel 10 such as a wind force as shown in FIG. 4A or 4B, transfer only the horizontal component of the force to the linear actuator (not shown) that moves the solar panels so that the linear actuator is protected for undesirable forces. For the gimbal sleeve coupling shown in FIG. 4A, at a 45 degree angle of the solar panel 10, 70.7% of the force is transferred to the horizontal beam 80 through the sleeve bearings 93, 94 which is much smaller than the force on the torque lever arm 72. The gimbal sleeve bearing allows the lever arm 72 to slide to change the length of the lever arm as the coupling element moves horizontally. Thus, the lever arm is shortest when the solar panel is at a zero degree angle. Similarly, for the pin and slot coupling shown in FIG. 4B, the coupling allows the level arm 72 to slide to change the length of the level arm as the coupling element moves horizontally.

FIG. 5 illustrates an example of another embodiment of a portion of a southerly tilted solar tracking system 200. As with the other embodiment, the system 200 have a plurality of solar modules 201 (solar panel assemblies) which are mounted on a torque frame 202 that rotates and causes the solar modules 201 to rotate as described above for the other embodiment. In this embodiment, the torque frame 202 may be coupled to a single solar module/solar panel assembly or multiple solar panel assemblies/solar modules as shown in FIG. 5. The torque frame 202, in one implementation, may further comprise a first rail 202a and a second rail 202b as shown that may be placed about 3 feet apart and support the solar panel assemblies. The torque frame 202 may also comprise a cross member 204 that connects the two rails 202a, 202b and supports the solar panels 201 at about the same position as the torque tubes are as shown in FIG. 1. In one implementation, the cross member 204 may be a first and second cross member 204a, 204b spaced apart with a lever arm 208 between them and a bearing journal 206 that extends from the cross member and allows the torque frame and the solar panels 201 to rotate. The lever arm (similar in operation to the lever arm described above) attaches to the crossmember 204 and the system works as described above wherein there is a drive member or driven mechanism (such as a rod) coupled to the level arm that translates the linear motion of the drive member into rotational motion of the torque frame and solar panels so that the solar panels track the sunlight as described above.

While the foregoing has been with reference to a particular embodiment of the system and method, it will be appreciated by those skilled in the art that changes in this embodiment may be made without departing from the principles and spirit of the system and method, the scope of which is defined by the appended claims.

Claims

1. A solar tracking assembly, comprising:

a solar panel assembly;

a torque device coupled to the solar panel assembly;

a lever arm rotatably coupled to the torque device;

a drive mechanism coupled to the lever arm; and

wherein a linear movement of the drive mechanism is translated into a rotational motion of the torque device and the solar panel assembly by the lever arm about a north-south axis so that the solar panel assembly tracks a plurality of rays of sunlight.

2. The assembly of claim 1 further comprising a second solar panel assembly, a second torque device coupled to the solar panel assembly and a second lever arm rotatably coupled to the second torque device wherein the second lever arm is coupled to the drive mechanism so that linear movement of the drive mechanism is translated into a rotational motion of the first and second torque devices and the first and second solar panel assemblies by the lever arm about a north-south axis so that the solar panel assemblies track a plurality of rays of sunlight.

3. The assembly of claim 2, wherein the drive mechanism is a rod.

4. The assembly of claim 3, wherein the drive mechanism further comprises a sleeve bearing and a gimbal that couple the level arm to the rod.

5. The assembly of claim 3, wherein the drive mechanism further comprises a rod and a pin that couple the level arm to the rod.

6. The assembly of claim 2, wherein the drive mechanism further comprises a linear actuator.

7. The assembly of claim 2 further comprising a frame anchored to a surface and wherein each torque device further comprises a torque tube that rotates relative to the frame.

8. The assembly of claim 7, wherein each torque device further comprises a torque tube bearing that rotatably supports the torque tube and the solar panel assembly relative to the frame.

9. The assembly of claim 2 further comprising a frame anchored to a surface having a first horizontal support and a second horizontal support spaced apart from each other and wherein each torque device further comprises a torque tube that rotates relative to the frame.

10. The assembly of claim 9 wherein each torque tube further comprises a first torque tube bearing that rotatably supports the torque tube and the solar panel assembly relative to the first horizontal support and a second torque tube bearing that rotatably supports the torque tube and the solar panel assembly relative to the second horizontal support.

11. The assembly of claim 1, wherein the solar panel assembly further comprises a plurality of solar panels and wherein the torque device further comprises a torque frame that is coupled to the solar panel assembly wherein the torque frame rotates the plurality of solar panels simultaneously.

12. The assembly of claim 9, wherein the first horizontal support and a second horizontal support spaced apart six to twelve feet.

13. The assembly of claim 9, wherein the first horizontal support and a second horizontal are at different heights so that each solar panel assembly is tilted.

14. The assembly of claim 13, wherein each solar panel assembly is tilted 15 to 30 degrees.

15. A method for tracking for a solar panel assembly, comprising:

providing a solar panel assembly and a torque device coupled to the solar panel assembly;

rotatably coupling a lever arm to the torque device;

linearly moving a drive mechanism coupled to the lever arm; and

translating the linear movement of the drive mechanism into a rotational motion of the torque device and the solar panel assembly by the lever arm about a north-south axis so that the solar panel assembly tracks a plurality of rays of sunlight.

16. The method of claim 15 further comprising rotatably coupling the lever arm to the drive mechanism using a sleeve bearing and a gimbal that couple the level arm to the drive mechanism.

17. The method of claim 15 further comprising rotatably coupling the lever arm to the drive mechanism using a rod and a pin that couple the level arm to the drive mechanism.

18. The method of claim 15, wherein linearly moving the drive mechanism further comprises actuating a linear actuator to linearly move the drive mechanism.

19. The method of claim 15, wherein providing a solar panel assembly and a torque device coupled to the solar panel assembly further comprises providing a torque tube that is coupled to the solar panel assembly.

20. The method of claim 19, wherein providing a solar panel assembly and a torque device coupled to the solar panel assembly further comprises providing a torque bearing that rotatably supports the torque tube and the solar panel assembly relative to a frame.

21. The method of claim 15, wherein providing a solar panel assembly and a torque device coupled to the solar panel assembly further comprises providing a torque tube that is coupled to the solar panel assembly.

22. The method of claim 21, wherein providing a solar panel assembly and a torque device coupled to the solar panel assembly further comprises providing a first torque tube bearing that rotatably supports the torque tube and the solar panel assembly relative to a first horizontal support and a second torque tube bearing that rotatably supports the torque tube and the solar panel assembly relative to a second horizontal support.

23. The method of claim 15, wherein the solar panel assembly further comprises a plurality of solar panels and providing a solar panel assembly and a torque device coupled to the solar panel assembly further comprises providing a torque frame that is coupled to the solar panel assembly wherein the torque frame rotates the plurality of solar panels simultaneously.

24. The method of claim 15, wherein providing a solar panel assembly and a torque device coupled to the solar panel assembly further comprises tilting the solar panel assembly 15 to 30 degrees.

25. A solar energy collection facility, comprising:

a plurality of solar panel assemblies arranged in a first east-west row, each solar panel assembly in the east-west row having a torque device coupled to the solar panel assembly and a lever arm rotatably coupled to the torque device; a drive mechanism coupled to the lever arms of the plurality of solar panel assemblies arranged in the first east-west row wherein a linear movement of the drive mechanism is translated into a rotational motion of the torque device and the solar panel assemblies by the lever arm about a north-south axis so that the solar panel assembly tracks a plurality of rays of sunlight; and

a plurality of solar panel assemblies arranged in a second east-west row spaced apart from the first east-west row, each solar panel assembly in the second east-west row having a torque device coupled to the solar panel assembly and a lever arm rotatably coupled to the torque device; a second drive mechanism coupled to the lever arms of the plurality of solar panel assemblies arranged in the second east-west row wherein a linear movement of the second drive mechanism is translated into a rotational motion of the torque device and the solar panel assemblies by the lever arm about a north-south axis so that the solar panel assembly tracks a plurality of rays of sunlight.

26. The facility of claim 25, wherein the first and second drive mechanisms are each a rod.

27. The facility of claim 26, wherein the first and second drive mechanisms each further comprise a sleeve bearing and a gimbal that couple the level arm to the rod.

28. The facility of claim 26, wherein the first and second drive mechanisms each further comprise a rod and a pin that couple the level arm to the rod.

29. The facility of claim 25, wherein the first and second drive mechanisms each further comprise a linear actuator.

30. The facility of claim 25, wherein each east-west row of solar panel assemblies further comprises a frame anchored to a surface and wherein each torque device further comprises a torque tube.

31. The facility of claim 30, wherein each torque tube further comprises a torque tube bearing that rotatably supports the torque tube and the solar panel assembly relative to the frame.

32. The facility of claim 25, wherein each east-west row of solar panel assemblies further comprises a frame anchored to a surface having a first horizontal support and a second horizontal support spaced apart from each other and wherein each torque device further comprises a torque tube.

33. The facility of claim 32, wherein each torque tube further comprises a first torque tube bearing that rotatably supports the torque tube and the solar panel assembly relative to the first horizontal support and a second torque tube bearing that rotatably supports the torque tube and the solar panel assembly relative to the second horizontal support.

34. The facility of claim 32, wherein the first horizontal support and a second horizontal support spaced apart six to twelve feet.

35. The facility of claim 32, wherein the first horizontal support and a second horizontal are at different heights so that each solar panel assembly is tilted.

36. The facility of claim 35, wherein each solar panel assembly is tilted 15 to 30 degrees.

37. The facility of claim 25, wherein the first and second east-west rows of solar array assemblies are spaced apart so that the plurality of solar panel assemblies arranged in a second east-west row do not shade the plurality of solar panel assemblies arranged in a first east-west row.

38. The facility of claim 25, wherein the solar panel assembly further comprises a plurality of solar panels and wherein each torque device further comprises a torque frame that is coupled to the solar panel assembly wherein the torque frame rotates the plurality of solar panels simultaneously.