SOLAR STRUCTURES

FIELD OF INVENTION

The present invention relates to the field of assembly structures for supporting solar panels, reflectors, lenses or other optical devices. This invention also relates to a novel design of solar tracker manufactured with metal or any other material profiles.

BACKGROUND OF THE INVENTION

Solar collectors provide greater performance when sunlight strikes perpendicular to the solar panel's surface.

In one instance it is possible to improve the performance of a solar collector or panel by varying its inclination throughout the year because the height of the sun varies everyday throughout the seasons. This type of structure with variable inclination angle is known as a adjustable tilt structure. These are usually designed with two or three possible angles of inclination according to the latitude of the site.

In flat panel photovoltaic applications, seasonal tilt structures are used to minimize the angle of incidence between the incoming sunlight and a photovoltaic panel during the year, but this can be not enough for other applications. For this reason there has been developed different types of solar trackers using various techniques and designs to follow the sun's movement. A solar tracker is a device that orients a solar generator towards the sun. This increases the amount of energy produced from a fixed amount of installed power generating capacity.

In concentrated photovoltaic and solar thermal applications, trackers are used to enable the optical components in both systems. This optics in concentrated solar applications accepts the direct components of sunlight and therefore must be oriented appropriately to collect energy. Tracking systems are found in all concentrator applications because such systems do not produce energy unless pointed at the sun. The solar trackers are usually classified according to their movement axes as follows:

• Single axis trackers have one degree of freedom that acts as an axis of rotation. The axis of rotation of single axis tracker is typically aligned along a true north meridian. It is possible to align them in any cardinal direction with advanced tracking algorithms.

• Dual axis trackers have two degrees of freedom that act as axes of rotation. These axes are typically normal to one another. The axis that is fixed with respect to the ground can be considered as primary axis. The axis that is referenced to the primary axis can be considered as secondary axis.

There are several common implementations of trackers. They are classified by the orientation of their primary axis with respect to the ground. Two common implementations are tip-tilt trackers and azimuth-altitude trackers.

A tip-tilt tracker is so named because the panel array is mounted on top of a pole. Normally the east- west movement is driven by rotating the array around the top of the pole. On top of the rotating bearing is a T or H shaped mechanism that provides vertical rotation of the panels and provides the main mounting points for the array.

Other such tip-tilt trackers have a horizontal primary axis and a dependant orthogonal axis. The vertical azimuthal axis is fixed. This provides a greater flexibility to the solar panel connecting the ground mounted equipment because there is no twisting of cable around the pole. Field layouts with tip-tilt trackers are very flexible. The simple geometry means that keeping the axes of rotation parallel to one another is all that is required for appropriately positioning the trackers with respect to one another. Normally the trackers would have to be positioned at a fairly low distance in order to avoid one tracker casting a shadow on other when the sun is low in the sky. Tip-tilt trackers can make up for this by tilting closer to the horizontal side thus minimizing up-sun shading and maximizing the total power being collected.

The axes of rotation of many tip-tilt trackers are typically aligned either along a true north meridian or an east-west line of latitude. An azimuth-altitude dual axis tracker has its primary axis (the azimuth axis) vertical to the ground. The secondary axis (often called elevation axis) is then typically normal to the primary axis. They are similar to tip-tilt systems in operation, but they differ in the way the array is rotated for daily tracking. Instead of rotating the array around the top of the pole, azimuth-altitude dual axis tracker systems can use a large ring mounted on the ground with the array mounted on a series of rollers. The main advantage of this arrangement is that the weight of the array is distributed over a portion of the ring, as opposed to the single loading point of the pole in the tip-tilt dual axis trackers. This allows azimuth-altitude dual axis tracker to support much larger arrays. Unlike tip-tilt dual axis trackers, the azimuth-altitude dual axis tracker system cannot be placed together with the diameter of the ring, which may reduce the system density, especially considering inter-tracker shading.

Trackers allow for optimum solar energy levels due to their ability to follow the sun vertically and horizontally. No matter where the sun is in the sky, dual axis trackers angle themselves to be in direct contact with the sun as possible.

The conditioning factors that allow choosing between different options can be many and in establishing the criteria for choosing between different solutions to support the solar panels, experts not just reach an agreement.

Roughly, for photovoltaic installations one must choose between fixed structures or trackers. In general, investments in fixed installations are low because the production cost is also low. The common constraints one has to face during photovoltaic installations are the geographical location of the facility, availability of land and its geological features, complexity of the work etc.

Once you have chosen a system with trackers, it must be chosen between single axis and dual axis. There are mostly pros for both options. Generally dual-axis trackers are more accurate in pointing directly at the sun. However, dual axis tracker comes at the price of higher complexity and lower reliability (more down time and more maintenance) than single axis tracker. On the other hand single axis tracker offers lower cost and higher reliability since there are only fewer things that can go wrong over the life of the system. SUMMARY OF THE INVENTION

The present invention provides a diagonal variable length system for angular movement of solar structures, wherein said system comprises:

- at least a solar panel configured to receive and convert sunlight to thermal or electrical energy,

- a support structure for mounting said solar panel, and

- a parallelogram or rhomboidal shaped solar tracker with a diagonal length varying mechanism for connecting and orienting at least two of said support structure towards the direction of the sun,

wherein said diagonal length varying mechanism is configured to change the shape of said solar tracker, thereby tilting said support structure in said direction of the sun.

According to one embodiment of the invention, wherein said diagonal length varying mechanism is a linear actuator comprising:

- a telescopic case configured to extend and/or contract when actuated by a motor, and

- a pair of couplings provided at the either end of said telescopic case for detachably fastening said telescopic case with said solar tracker, wherein said motor is positioned within one of said couplings.

According to one embodiment of the invention, wherein said diagonal length varying mechanism is a jack screw.

According to another embodiment of the invention, wherein said diagonal length varying mechanism is a scissor mechanism comprising:

- a scissor jack bar configured to expand and/or contract,

- a pair of couplings for detachably fastening said scissor jack bar with said solar tracker, and

- a screw with a screw nut at one end for expanding and/or contracting said scissor jack bar when actuated by a motor disposed at the other end of said screw, wherein said motor when actuated is configured to rotate said screw thus moving said screw nut along the direction of said screw for enabling said scissor jack bar to expand and/or contract.

According to a further embodiment of the invention, wherein said diagonal length varying mechanism is a motorised pulley mechanism.

According to yet another embodiment of the invention, wherein said diagonal length varying mechanism is configured to move said solar tracker in an east-west direction.

According to a particular embodiment of the invention, wherein said diagonal length varying mechanism is configured to move said solar tracker in a north-south direction.

According to a similar embodiment of the invention, wherein said diagonal length varying mechanism is configured to move said solar tracker in a zenithal direction.

According to one of the embodiment of the invention, wherein said support structure and solar tracker are formed by metal profiles of galvanized steel.

According to a particular embodiment of the invention, wherein said support structure and solar tracker are formed by non-metallic material.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

For better understanding, various embodiments of the invention will now be described with reference to the accompanying drawings. It will, however, be appreciated that the embodiments exemplified in the drawings are merely illustrative and not limitative to the scope of the invention, because it is quite possible, indeed often desirable, to introduce a number of variations in the embodiments that have not been shown in the drawings. In the accompanying drawings:

Figure 1 illustrates the invented diagonal variable length system for angular movement of solar structures. Figure 2 shows in detail the parallelogram shaped solar tracker along with the linear actuator. Figure 3 shows in detail the linear actuator in contracted position.

Figure 4 shows in detail the linear actuator in expanded position.

Figure 5 shows an example of change in shape of the parallelogram shaped solar tracker when the linear actuator length changes.

Figure 6 shows the movement of solar trackers along the north-south axis.

Figure 7 shows the movement of solar trackers along the east- west axis.

Figure 8 shows the movement of solar tracker along the zenithal axis.

Figure 9 illustrates the solar panels facing the west when viewed from the south side.

Figure 10 illustrates the solar panels in horizontal position when viewed from the south side.

Figure 11 illustrates the solar panels facing the east when viewed from the south side.

Figure 12 shows the invented system with a scissor mechanism.

Figure 13 illustrates in detail the expanded position of the scissor mechanism.

Figure 14 illustrates in detail the contracted position of the scissor mechanism.

Figure 15 illustrates the invented system with multiple scissor mechanisms for tilting the solar panels.

Figure 16 shows a different configuration of structure of the solar tracker.

Figure 17 shows the invented system with a pulley mechanism.

Figure 18 shows a jack screw used as a diagonal length varying mechanism.

DETAILED DESCRIPTION OF THE DRAWINGS

Reference will now be made to the exemplary embodiments of the invention, as illustrated in the accompanying drawings. Wherever possible same numerals will be used to refer to the same or like parts.

The present invention as shown in figures 1 and 2 provide a diagonal variable length system (100) for angular movement i.e. tilting of solar structures like solar panels. The invention comprises of a diagonal variable length system (100) for supporting or mounting solar panels (102). The solar panels (102) are mounted on a support structure (103). The diagonal variable length system (100) provides a novel solar tracker (104) for tilting or orienting said solar panels (102) based on the direction of the movement of the sun. The solar tracker (104) is a parallelogram or rhomboidal shaped structure. The parallelogram shaped structure has two pairs of parallel sides (104-1, 104-2, 104-3, and 104-4). The solar tracker (104) is configured to be tilted in a predefined angle by means of said diagonal length varying mechanism (105). The diagonal length varying mechanism used here is a linear actuator (106). The linear actuator (106) is mounted diagonally in the parallelogram shaped structure. The linear actuator (106) tilts the parallel sides (104-1, 104-2, 104-3, and 104-4) of the solar tracker (104) by changing its length, thereby orienting said solar panel (102) with the sun. Figure 5 shows the change in length of the parallelogram, in other words the change in length of the parallelogram shaped solar tracker (104) when the diagonal length or element i.e. the linear actuator (106) length increases or decreases. In this scenario, the length of the parallel sides (104-1, 104-2) and (104-3, 104-4) remains the same, whilst the diagonal length i.e. the linear actuator (106) length changes. The aforesaid mechanism of changing the diagonal length is applied in said diagonal variable length system (100). Thus the solar panel (102) can be moved along the direction of the sun according to seasons.

Figure 3 and figure 4 shows the linear actuator (106) in detail. Figure 3 shows the linear actuator (106) in contracted position and figure 4 shows said linear actuator (106) in an expanded or extended position. The linear actuator (106) comprises of a telescopic case (106- 1), a pair of couplings (106-2) and a motor (106-3). The telescopic case (106-1) is configured to extend or contract, thereby increasing or decreasing the length of said linear actuator (106). The linear actuator (106) is mounted in said parallelogram shaped solar tracker (104) by means of the couplings (106-2). The couplings (106-2) are provided at either ends of said linear actuator (106). The couplings (106-2) detachably fasten the linear actuator (106) to the solar tracker (104). The expansion and contraction of said linear actuator (106) is monitored and controlled by the motor (106-3). The motor (106-3) is positioned within one of said couplings (106-2). The motor (106-3) upon operation is configured to elongate and/or contract the length of said linear actuator (106) to a preset length. An example of the linear actuator (106) movement is shown in figures 9, 10 and 11. In these figures the solar panel (102) is viewed from the south side in three different positions. In figure 9 the solar panel (102) faces the west, in figure 10 the solar panel (102) is in a horizontal position and in figure 11 the solar panel (102) faces the east. Thus the above said figures clearly illustrate the variation in the linear actuator (106) length thus moving the solar panel (102) in the direction of the sun. As shown in figure 18, the diagonal length varying mechanism (105) used can be a jack screw (107). Figures 6, 7 and 8 show the different axis of rotational movement of the solar panel (102) due to the variation in diagonal length i.e. the variation in linear actuator length (106). These figures illustrate that the parallel sides (104-1, 104-2, 104-3, and 104-4) of the parallelogram shaped solar tracker (104) remains the same in length, whereas, there is a change in length of the linear actuator (106). Figure 6 shows the movement of the solar panels (102) in the north- south axis. Figure 7 shows the movement of said solar panels (102) in the east-west axis. Similarly, figure 8 shows the movement of the solar panel (102) along its zenithal axis.

The parallelogram shaped solar tracker (104) can also be tilted by employing a scissor mechanism (108) acting as the diagonal length varying mechanism. The scissor mechanism (108) comprises of scissor jack bars (108-1), screw (108-2), screw nut (108-3), a motor (108- 4) and couplings (108-5). The couplings (108-5) enable the scissor mechanism (108) to be mounted to the solar tracker (104). Figure 12 illustrates the scissor mechanism (108) mounted on said parallelogram shaped solar tracker (104) to tilt the solar panels (102) along the direction of the sun. The detailed view of the scissor mechanism (108) is illustrated in figures

13 and 14. Figure 13 shows the extended position of said scissor mechanism (108) and figure

14 shows the contracted position of the scissor mechanism (108). The motor (108-4) is coupled with the screw (108-2). The motor (108-4) upon operation is configured to spin said screw (108-2). Once the screw (108-2) begins to spin, the screw nut (108-3) begins to moves along the direction of said screw (108-2) for opening or expanding and closing or contracting the scissor jack bars (108-1) thereby enabling the angular movement of said solar panels (102). In the scissor mechanism (108) a single threaded rod can trigger various scissors. This solution can be adapted to the topography and it is planned to incorporate several articulations. One of the articulations that can be adopted is shown in figure 15. Figure 15 shows the solar tracker (104) with multiple scissor mechanisms (108). The multiple scissor mechanisms (108) enable the tilting of the support structures (103) together with the solar panels (102) in the direction of the sun. The present invention enables the solar panel (102) to be designed on a modular assembly. This allows said solar panels (102) to adapt easily to the constraints of land availability, or to the electrical configuration of the plant, or both at once. Moreover, a modular assembly enables a reduction in size of the pieces that form the solar panel (102), and hence the use of heavy machinery for assembling the system (100) is not necessary. That will ease the assembling procedure by reducing the time consumed for assembling the system (100) and also reduces the labour or man hours required to install said system (100). Figure 16 shows a different configuration of structure for the solar tracker (104). Here, the fixed points of the parallelogram shaped solar tracker (104) are no longer its vertices, but in the middle of section (a). The diagonal (1) (as shown in figure 16c) can be joined to the middle of the pole, or remain free only held by the vertices (a, b). In this configuration, the solar tracker (100) is configured to tilt when there is a change in the diagonal (1) length.

Figure 17 shows a pulley mechanism (110) used as the diagonal length varying mechanism (105) for tilting the solar trackers (104) in the direction of the sun. The pulley mechanism (110) comprises of single and/or double pulleys (110-1) which are moved by means of a rope or wire (110-2). The rope (110-2) is connected to a motor (110-3) (not shown in figure 17) for rotating said pulleys (110-1), thus tilting the solar tracker (104) and with it the solar panels (102) in the direction of the sun.

The dimensions and sections of the metallic profiles that form the solar tracker (104) must be calculated for each particular case depending on the dimensions of solar panels (102), terrain characteristics and climatic conditions of the site where it is expected to mount the solar panel (102).

There is also the possibility to use other materials for the profiles to build the support structure (103) and solar tracker (104); this will depend on the conditions of every project or installation.

This invention allows the solar tracker (104) to be designed on a modular assembly. This allows said solar trackers (104) to adapt easily to the constraints in available land, or to the electrical configuration of a plant, or both at once. Moreover, a modular assembly enables a reduction in the size of the pieces that form said solar tracker (104), and hence the use of heavy machinery for assembly is not necessary. This will ease the assembling within less time and with less labour or man hours.

As already mentioned the foregoing description is illustrative of the invention and not limitative to its scope; because it will be apparent to persons skilled in the art to devise other alternative embodiments without departing from the broad ambit of the disclosures made herein.