WO2013124870A2

WO2013124870A2 - System and method for solar panel array sun tracking

Info

Publication number: WO2013124870A2
Application number: PCT/IN2013/000111
Authority: WO
Inventors: Inderpreet Singh Wadhwa
Original assignee: Inderpreet Singh Wadhwa
Priority date: 2012-02-23
Filing date: 2013-02-25
Publication date: 2013-08-29
Also published as: WO2013124870A3

Abstract

A system and a method for a installing a solar panel array are provided. The solar panels are installed on rotational supports connected between poles mounted into the ground. Connection between the rotational supports and the pole has pre-drilled holes that allow the solar panels to be mounted at desired tilt relative to horizontal. Also provided are the necessary parts and assembly instructions of the solar panel with its supporting structure and assembly thereof based on pre-drilled holes. The pre-drilled holes are based on a combination of season, and latitude and longitude, geography of the site of installation of the solar panels.

Description

SYSTEM AND METHOD FOR SOLAR PANEL ARRAY SUN TRACKING

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Indian Provisional Patent Application 524/DEL/2012, entitled "MANUAL SOLAR TRACKING SYSTEM," and filed February 23, 2012, the disclosure of which is incorporated herein by reference.

[0003] FIELD OF INVENTION

[0004] The invention relates to relates to a tracking system for use in solar power generation, and to the arrangement of solar panel drive and tilt mechanisms to follow the movement of the sun relative to the earth. The invention more specifically relates to a drive mechanism for rotating a large array of solar panels in a cost effectively.

[0005] BACKGROUND OF THE INVENTION

[0006] Solar energy now is a viable solution to meeting the ever increasing demand for energy.

[0007] Use of photovoltaic cells is one method of harnessing the sun's energy. Use of photovoltaic cells involves direct conversion of light into electricity at the atomic level. Some materials exhibit a property-photoelectric effect that causes them to absorb photons of light and release electrons. When these free electrons are captured, electric current is used as electricity. Photovoltaic devices (solar cells) are unique as they directly convert the incident solar radiation into electricity, with no noise, pollution or moving parts, making them robust, reliable and long lasting. To efficiently implement the photoelectric effect, a device must track the sun in proper orientation.

[0008] The have been many ways in which this has been attempted. For example, a sun tracking system which is capable of maintaining the desired orientation of a panel of solar cells or collectors at all times throughout the day and year, but these efforts have yet to yield a sufficiently effective low cost sun tracker.

[0009] In one such method, a closed loop servo system is provided for continuously pointing a solar cell directly toward the sun by sensing the sun's position and selectively driving the solar cell support about one or the other of a pair of axis. Devices of this type-heliostats-are well known, but suffer from a number of drawbacks especially including high cost and complexity. In addition, the system is complex and expensive to maintain because of a gear system with a single drive motor and an electrically operated clutch to permit selective dual axis drive.

[0010] In others such system, separate drive motors for obtaining dual axis movement is employed. While useful for the purposes disclosed, these closed loop servo systems, that is, systems employing sun position sensors for controlling the timing and amount of tracking movement by the servo system, are costly to install and are subject to mechanical or electrical breakdown which adversely affects their reliability.

[0011] During periods of partial cloud cover, the ability of such systems to track the sun may be impaired. And thus, require the system to include an open loop servo capability, that is an ability to track the positions of the sun without using sun position sensors.

[0012] The use of both an open loop and closed loop servo control in the same system adds significantly to the cost of initial installation and maintenance of a sun tracking apparatus.

[0013] Hence there is a need for a system and a method for a device to track the sun in proper orientation at a low level of complexity, easy to install, and cost effective, and yet efficient and reliable.

[0014] SUMMARY OF THE INVENTION

[0015] Accordingly, it is an object of the invention to provide a solar tracking system that is easy to install, and operate, yet efficient and reliable. [0016] BRIEF DESCRIPTION OF DRAWINGS

[0017] The following detailed description of the preferred embodiments will be better understood when read in conjunction with the appended drawings. The invention is illustrated by way of example and not limited by the accompanying figures, in which like references indicate similar elements.

[0018] FIG.IA and FIG.IB depict an example embodiment of equipment drawing for rotational support;

[0019] FIG.2A and FIG.2B depict an example embodiment of base plate, U-Clamp and radial bolt;

[0020] FIG. 3A and FIG.3B depict an example arrangement embodiment of spindle, angle fixing pin, and torque tube;

[0021] FIG.4 shows an example arrangement of spindle mounting clamp;

[0022] FIG. 5 depicts an example arrangement of torque tube slot clamp;

[0023] FIG.6 depicts an example arrangement of cinch tube and cinch plate;

[0024] FIG. 7 depicts an example arrangement of panel mounting rail, C Clamp and

W Clamp;

[0025] FIG. 8 shows a rotational support cradle assembly that includes a cinch tube, cinch tube bolts, cinch plate, base plate, pivot bracket, rotational and support bearing pin;

[0026] FIG. 9 shows various components used: including U clamps for rail fixing, rotational support tube caps, angle fixing pins, rotational support tube, and panel mounting rails;

[0027] FIG. 10 shows an example for installing row posts installed according to a site plan;

[0028] FIG. 11 depicts a completed assembly of the mechanical structure of the modules of FIG. 1 - FIG. 7;

[0029] FIG. 12 depicts the installation procedure for fixing pivot brackets;

[0030] FIG. 13 depicts the procedure for installing the rotational support cradle;

[0031] FIG. 14A and FIG. 14B illustrates the use of pre-drilled holes to obtain a desired tilt level; [0032] FIG. 15 depicts the use of the adjustment pin;

[0033] FIG. 16 depicts the installation of rotational support tube;

[0034] FIG. 17 A and 17B depicts the installation of the panel rail; and

[0035] FIG. 18A and FIG. 18B depict the installation of C clamps and Waffle clamps respectively.

[0036] DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0037] Preferred embodiments of the present invention will be described in detail herein below with reference to the attached drawings.

[0038] The tracking system of the invention offers high increase in yield while also ensuring extremely high durability of the tracking system to match the longevity of the solar panel systems. The method and system of the present invention are based on tracking of large-scale (mega-watt plus) solar panel arrays. The system and method disclosed allow for easy latitude and time-of-year adjustment of the large- scale solar arrays to increase power output throughout the day by season most relevant for geography.

[0039] The invention relates to a tracking system which is not just cost effective but also ensures high durability since it is based on easy latitude and time-of-year adjustment of the large-scale solar arrays. The system of tracks the sun without the use of any moving parts and is yields are enhanced by almost 5-10% in one embodiment, and higher yields in other embodiments.

[0040] The solar tracking system disclosed provides robust single-axis pole mounting system offering several advantages. It reduces the overall system cost by maximizing the Solar Array System area per pole foundation, reducing installation time, foundation requirements and labor cost.

[0041] The system offers a unique Out of the box' latitude versatility for large scale systems by simple pre-defined tilt schedules for each season and geography, thereby ensuring simple yet robust tracking mechanism.

[0042] The system and methods disclosed in the tracking system does not observe any wear and tear as there are no moving parts involved in the system. This results in higher system life and reliability to match earlier Solar Array Systems. The system comprises extremely durable and corrosion resistant galvanized steel components and anodized aluminum panel rails further ensuring long life.

[0043] Further, the system operates on a dual beam rotational system thereby allowing for a very large number of modules to be supported using minimum number of foundations.

[0044] There are several other advantages of the system: at least three inches of vertical and lateral adjustability at each post, compatibility with most commercially available modules, use of C-Clamps and Waffle Clips for quick and clean module attachment and wind resistance capability up to 90 miles per hour (MPH) at the International Building Code (IBC) Exposure Category C (dependent on foundation requirements).

[0045] In one embodiment the MST system consists of a frame (hot dip galvanized mild steel) upon which the panels are rested. The system is kept at such an angle that the panels receive maximum sunlight to produce electricity. The system uses an array of solar panels that are installed on rotational supports connected between poles mounted into the ground. The connection between the rotational supports and the pole has pre-drilled holes that allow the panels to be mounted at desired tilt relative to horizontal to account for the latitude and declination of the sun throughout the year.

[0046] Major components comprised in the MST system are: i. Row post or Support Post; ii. Rotational Support Cradle Assembly: including Cinch Tube; Cinch Tube Bolt; Cinch Plate; Base Plate; Pivot Bracket; Rotational Support Cradle; Rotational Support Bearing Pin; iii. Cradle Adjustment Pin; iv. Rotational Support Cap and Beam; v. Panel Rail & Rail Clamp; vi. C-Clamp and Waffle Clip.

[0047] Row Post/Support Post: Row post is a medium grade, 100NB, GI pipe. The height of the Row post varies, depending upon the design requirements and site layout plans. All the posts have to be installed according to the site layout plan. Each Row Post must be installed perpendicular to the horizontal ground surface and aligned as per the allowable tolerance limits. Γ00481 Rotational Support Cradle Assembly: The whole mechanical assembly of the MST system consists of: a) The Cinch Tube assembly comprises of Cinch Tube (both parts), Cinch Plate, Base Plate and Radial Bolt with spring & flat washer, b) The Pivot Bracket is fixed upon the Base Plate which in turn is fixed to the Cinch Tube Assembly. The Rotational Support Cradle is attached to the Pivot Clamp by inserting the Rotational Support Bearing Pin through the aligned holes of the Pivot Bracket. This allows the whole system to rotate about its bearing pin.

[0049] The rotational support cradle is made using Galvanized Iron and detailed according to FIG. 1A and FIG. IB. A set of M08x25 with washers is used. In one embodiment, four such sets are used. The figures in FIG 1A and FIG. IB are not according to scale and for illustrative purposes only.

[0050] FIG. 2A and FIG. 2B depict an example embodiment of base plate, U-Clamp and radial bolt. The figures in FIG 2 are not according to scale and for illustrative purposes only.

[0051] FIG. 3A and FIG.3B depict an example arrangement embodiment of spindle, angle fixing pin, and torque tube. The spindle, angle fixing pin may be made of stainless steel or any other suitable metal / alloy.

[0052] FIG.4 shows an example arrangement of spindle mounting clamp.

[0053] FIG. 5 depicts an example arrangement of torque tube slot clamp. The torque tube slot clamp may be configured, in one embodiment, by a set of M12x35 bolts, nuts, and split washers, and M12x25 bolts.

[0054] Cradle Adjustment Pin: The Rotational Support Cradle can be adjusted to get the required tilt by aligning pre-defined tilts of required angle given on the Cradle, to the holes provided in the Pivot Clamp. The Rotational Support Cradle can be adjusted to the required tilt by inserting the Angle Fixing Pin or Cradle Adjustment Pin in between the aligned holes on the Rotational Support Cradle and the Pivot Clamp.

[0055] Rotational Support Beam and Caps: The Rotational Support Beam forms the supporting framework for the Panel Rails that hold up the solar panels. Rotational Support Beams are kept in place with the help of the Rotational Support Caps which have to be bolted to the slots provided in the Rotational Support Cradle. FIG.6 depicts an example arrangement of cinch tube and cinch plate;

[0056] Panel Rail and Rail Clamp: The Panel Rail Assembly includes Panel Rail, Rail Clamp, C-Clamp and Waffle Clips. The Panel Rails are attached to the Rotational Support Beam with the help of Rail Clamp. These Panel Rails are attached over the Support Beams at a regular interval according to the design requirements of the mounting structure. The Panel Rail must be rested on the Rotational Support Beam through the groove provided at the bottom of the mounting panel rail.

[0057] C-Clamp & Waffle Clip: Photovoltaic modules can be placed upon the Panel Rails with the help of C-clamps and Waffle Clips, which enables to hold the solar modules at both the ends of the Panel Rails. FIG. 7 depicts an example arrangement of panel mounting rail, C Clamp and W Clamp. In one embodiment, the C clamp and Waffle clip are both 46mm.

[0058] Based on the layout as described, the tracking system provides a cost- efficient option for solar arrays, preferably large-scale arrays. The system is capable to overcome the challenges of existing systems yet being simple, convenient and durable.

[0059] Installation: Cinch Tube: In an embodiment, row posts are installed according to site plans / site layout. The cinch tube is then fixed in the row posts and tightened with a ratchet. The cinch tube holds the base plate to row post foundations. The supporting base plate allows for adjustment of the main assembly such that the rotational support tube is capable of being fit symmetrically. In one embodiment, the size of the cinch tube bolt is Ml2x300 Hexagonal head. FIG. 11 depicts the installation of the cinch tube.

[0060] Pivot Bracket Installation: In one embodiment, the pivot bracket is fixed on the cinch base plate. However, other suitable locations may also be used for fixing the pivot bracket. The pivot bracket is then adjusted so that it aligns centers of the rotational support bearing pins for the entire row, and then tightened using a ratchet. The bolts may be tightened either on all six tapped holes, or aligning them with the base plate, or on four corner holes.

[0061] Rotational Support Cradle Installation: The rotational support cradle may be placed on the pivot bracket by inserting rotational support bearing pin through the aligned holes. And such that the rotational support cradle is free to rotate about its rotational support bearing pin.

[0062] The rotational support cradle may be adjusted to get a desired tilt by aligning holes of desired angle ranging from 0 to 40 degree given on the rotational support cradle to the holes on the pivot bracket, and the angle fixing pin is inserted to manually fix at the desired tilt level.

[0063] Rotational Support Tube Installation: The cradle adjustment pin is inserted in each cradle to lock the cradle to a specific position. Then one half of rotational support caps are placed into the slot given in each rotational support cradle in a row. Then the rotational support tube is placed into the rotational support cap. After this, remaining rotational support caps are placed on the tube and tightened with nuts, bolts and washers.

[0064] In one embodiment, there are two slots for rotational support cap per rotational support cradle. The rotational support tubes are inserted at least 89 mm (3.5") into the rotational support caps. The size of the rotational support caps bolts may be M12x 35 hexagonal head type. And a quantity of four bolts per cap with eight split washers is used.

[0065] Panel Rail Installation: The panel rails are attached with the rotational support tube with rail clamps. The mounting panel rail is provided with a groove at the bottom. The panel rails rest on the rotational support tube through the groove.

[0066] The panel rail is placed onto the torque tubes at an appropriate spacing to support the photovoltaic modules. The rail clamps are attached on the panel rail by M8 bolts and washers, and placing the strut nuts inside the rail extrusion.

[0067] Photovoltaic Module Placement: The photovoltaic modules are placed on panel rails by C-Clamp and Waffle clamps.

[0068] A set of bolts used for each part is provided: [0069] Panel Mounting: (i) Cinch tube bolt - M12; (ii) Pivot bracket adjustment bolt - M12; (iii) Rotational support cap bolt - M12; (iv) Panel rail assembly clamp - M8; (v) C Clips - M8; (vi) Waffle clips - M8.

[0070] SMBC: DC Output cable connection: M12; DC input cable connection - M10 [0071] SSM: DC cable connection - M12;

[0072] Inverter: (i) AC cable connection - M16; DC cable connection - M12; SCIOO 100LV-M10.

[0073] Although the present invention has been described in considerable detail with reference to a preferred embodiment and example, other embodiments and equivalents are possible. Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with functional and procedural details, the disclosure is illustrative only, and changes may be made in detail, especially in terms of the structuring and implementation within the principles of the invention to the full extent indicated by the broad general meaning of the terms. Thus various modifications are possible of the presently disclosed system and method without deviating from the intended scope and spirit of the present invention. Accordingly, in one embodiment, such modifications of the presently disclosed system and method are included in the scope of the present invention.

Claims

CLAIMS I claim AVe claim:

1. A solar panel array sun tracking system, comprising:

an array of solar panels installed on rotational supports connected between poles mounted into the ground, wherein the connection between the rotational supports and the pole has pre- drilled holes allowing the solar panels to be mounted at desired tilt relative to horizontal, wherein the pre-drilled holes are based on schedules for a season and geography.

2. The solar panel array sun tracking system of claim 1, further comprising:

a plurality of row posts;

a plurality of rotational support cradle assembly, comprising:

a cinch tube;

a cinch tube bolt;

a cinch plate;

a base plate;

a pivot bracket;

a rotational support cradle;

a rotational support bearing pin;

a plurality of cradle adjustment pins;

a plurality of rotational support caps and beams

a plurality of panel rails and rail clamps; and

a plurality of C-Clamps and Waffle Clips.

3. The solar panel array sun tracking system of claim 2, wherein the plurality of row post are of a medium grade, 100NB, galvanized iron (GI) pipe, and -the height of the row post varies, and each row post is installed perpendicular to the horizontal surface, and aligned as per allowable tolerance limits.

4. The solar panel array sun tracking system of claim 2, wherein the rotational support cradle assembly is configured according to the pivot bracket being fixed upon the base plate which in turn is fixed to the cinch tube assembly, and the rotational support cradle is attached to the pivot clamp by inserting the rotational support bearing pin through the aligned holes of the pivot bracket to allow the system to rotate about the bearing pin.

5. The solar panel array sun tracking system of claim 4, wherein the rotational support cradle is adjusted to get a required tilt by aligning pre-defined tilts of required angle given on the cradle, to the holes provided in the pivot clamp.

6. The solar panel array sun tracking system of claim 5, wherein the rotational support cradle is further adjusted to a required tilt by inserting the cradle adjustment pin in between the aligned holes on the rotational support cradle and the pivot clamp.

7. The solar panel array sun tracking system of claim 4, wherein the rotational support beam forms supporting framework for the panel rails that hold up the solar panels, and the rotational support beams are kept in place rotational support caps which are bolted to slots provided in the rotational support cradle.

8. The solar panel array sun tracking system of claim 7, wherein the panel rail assembly includes a panel rail, rail clamp, C-clamps and waffle clips, and the panel rails are attached to the rotational support beam with a rail clamp, and the panel rail rest on the rotational support beam through the groove provided at bottom of the mounting panel rail.

9. . The solar panel array sun tracking system of claim 8, wherein the panel rails are attached over the support beams according to design requirements of the mounting structure.

10. The solar panel array sun tracking system of claim 2, wherein the photovoltaic modules are placed upon the panel rails using C-clamps and waffle clips.