Tracking System for Solar Panels

RELATED APPLICATIONS

[ 0001 ] This application claims priority to and benefit under 35 USC § 119(e) of the U.S. Provisional Application No. 61/157,793, filed on March 5, 2009, which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

[ 0002 ] Solar photovoltaic modules comprising solar cells or solar panels use light energy (photons) from the sun to generate electricity. The solar panels, usually combined in arrays, must be properly oriented with respect to the sun to be used efficiently.

[ 0003 ] Such solar panel arrays may be mounted on single poles. However for such single- pole mountings the wind effects limit the number of solar panels installed on each pole (to about 30 panels) and the strength requirements for the poles is significant and limiting. The cost of underground concrete footing and foundations and their size for such poles are large, and each pole must be provided with its own underground cable connection.

SUMMARY OF THE INVENTION

[ 0004 ] The present solar panel system tracks the sun from east in the morning to west in the evening and eliminates or reduces the aforementioned disadvantages of single-pole systems.

[ 0005 ] The present system is an improvement over a static system in that the efficiency is increased by at least 20-40% (the closer to the equator, the better) and the dimensions of the system on the ground are smaller for the same electric output. The amount of electric cable required is also reduced compared with single-pole systems. [ 0006 ] In general, according to one aspect, the invention features a system for orienting solar panels, having a rotating frame for mounting the solar panels; wheels attached to the rotating frame; at least one rail forming a circular track for the wheels; and at least one motor for rotating the frame on the wheels around a central axis of the track.

[ 0007 ] The system may have more than one concentric circular track for the wheels, which may be flanged. The frame may have a platform to which the wheels are attached and be inclined with respect to the platform. Each of the solar panels may be individually inclined with respect to the rotating frame. The frame may be a strut grid structure. The system may also have a foundation for the at least one rail and/or a computer controlling motion of the rotating frame and/or of the rotating frame with respect to the platform and/or of each of the solar panels with respect to the rotating frame. The circular track may be substantially parallel to the ground. The rotating frame may have a platform, to which the wheels are attached, and be inclinable with respect to the ground.

[ 0008 ] The above and other features of the invention including various novel details of construction and combinations of parts, and other advantages, will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the particular method and device embodying the invention are shown by way of illustration and not as a limitation of the invention. The principles and features of this invention may be employed in various and numerous embodiments without departing from the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[ 0009 ] In the accompanying drawings, reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale; emphasis has instead been placed upon illustrating the principles of the invention. Of the drawings:

[ 0010 ] Fig. 1 shows the rail tracks.

[ 0011 ] Fig. 2 shows a system for tracking sun with solar panels. [ 0012 ] Fig. 3 shows a wheel mounting of the system' s frame on rails.

[ 0013 ] Fig. 4 shows another kind of wheel mounting of the system's frame on rails.

[ 0014 ] Fig. 5 shows an example of a wheel used in the system.

[ 0015 ] Fig. 6 shows an example of the frame used for the present system.

[ 0016 ] Figs. 7 and 8 show the system with an inclinable frame.

[ 0017 ] Figs. 9 and 10 show the system with a frame inclined with respect to a platform.

[ 0018 ] Fig. 11 shows movement of individual solar panels.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[ 0019 ] Figs. 1 and 2 show a system for orienting an array of adjustable solar panels 1 mounted on a frame 6 and two concentric circular horizontal rail tracks 2 and 3 mounted via steel column supports 8 on a concrete footing and foundation 5 to rotate the frame 6 clockwise or counterclockwise around the central axis 20 using an electric motor 7 to follow the sun's motion in the sky for maximum utilization of available sun radiation. The number of rail tracks and motors may be different for different situations and chosen for stability, strength, and durability. Each rail track may be provided with its own motor or motors. These motors may be computer-controlled to rotate the frame 6 following the motion of the sun. The frame support comprises joist trusses 29.

[ 0020 ] Each supporting column 8 may have a different length or height to compensate for uneven g &r- ¹ ound and to ensure that the rail track 2 or 3 is level.

[ 0021 ] The number of rail tracks and their diameters are chosen considering the size of the frame 6 and the number of solar panels 1.

[ 0022 ] Figs. 3 and 4 show possible mountings of the frame 6 on the rail tracks 2 and 3. One such mounting is shown by the rectangle 9 on Fig. 2 [ 0023 ] The frame is mounted on wheels 10-11 or 14 as shown in Figs. 3 and 4, such as a flanged wheel shown in Fig. 5, via steel column supports 12. The wheels 10-11 or 14 are secured to rail tracks 2 or 3 at top and bottom to enable the frame 6 to rotate on the tracks 2 and 3 and to prevent separation of the wheels 10-11 or 14 from the rail tracks 2 or 3.

[ 0024 ] The frame 6 may be designed and assembled in various ways: as a bar joist system or a simplified space frame shown in Fig. 6 with half-octahedrons 21. A space frame or space structure is a truss-like, lightweight rigid structure constructed with interlocking struts in a geometric pattern. Space frames usually use a multidirectional span and are often used to provide long spans with few supports. They derive their strength from the inherent rigidity of the triangular frame; flexing loads (bending moments) are transmitted as tension and compression loads along the length of each strut. Often their geometry is based on platonic solids. The simplest form is a horizontal slab of interlocking square pyramids built from aluminium or steel tubular struts. In many ways this looks like the horizontal jib of a tower crane repeated many times to make it wider. A stronger purer form is composed of interlocking tetrahedral pyramids in which all the struts have unit length. More technically, this is referred to as an isotropic vector matrix or in a single unit width as an octet truss. More complex variations change the lengths of the struts to curve the overall structure or may incorporate other geometrical shapes.

[ 0025 ] Uitilizing unistrut metal framing, an original strut system, a steel joist trusses and beam system, or any similar structural system for the frame 6 would provide a maximum strength for the least amount of steel used and allow the frame to provide the maximum space for solar panels 1.

[ 0026 ] A grid 22 shown in Fig. 1 is attached to the top of the frame 6 using steel or aluminum L-shaped angles (similarly to an acoustical ceiling grid system). Each cell of the grid 22 holds a solar panel 1 and allows easy replacement of the solar panel 1.

[ 0027 ] As shown in Figs. 7-8, the frame 6 may be attached to a steel platform 23 or to a bar joist frame. The platform 23 is then attached to the wheels 10-11 or 14 on the rail track 2 with a movable frame support 24. The frame 6 may be variably inclined with respect to the ground by a hydraulic elevating device 25, which may be computer controlled, to follow the sun's position in the sky.

[ 0028 ] As shown in Figs. 9-10, the frame 6 may be set at a permanent angle to the ground and to the platform 23.

[ 0029 ] Instead of or in addition to the frame 6 changing its angle with respect to the platform 23, each individual solar panel 1 shown in Fig. 11 may change its angle to follow the sun. This may be computer-controlled.

[ 0030 ] Preliminary calculations show a possible number of individual solar panels of up to 1,000 compared with single-pole tracking systems, which can hold only up to 30 solar panels on one structural frame. To build a one-megawatt solar power station, the required facility size for the present invention is 2 acres (compared 8-10 acres for single-pole systems).

[ 0031 ] While this invention has been particularly shown and described with references to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.