SINGLE-AXIS GRAVITY-DRIVEN TRACKING METHOD FOR ALL TYPES OF PHOTOVOLTAIC PANELS

Abstract

The present invention relates to a single-axis device for tracking the sun's path in its orbit to provide photovoltaic (PV) panels with maximum sunlight at any time of day, thereby significantly improving their efficiency. The invention can be combined with patent application no. FR2310044, which allows for the addition of a BOX to the PV panel to recover the waste heat produced on its underside as electricity or other products (green hydrogen), thereby further increasing the productivity of the solar array. The process is fully automated, requires minimal mechanization (no motor, only a low-power pump), and is simple to install and maintain for single panels, whether in series or in a field, regardless of the terrain. The trackers can share certain resources.Specific control and management software optimizes radiation capture, automates the system, and enables remote monitoring. The invention allows for the collection of satellite water using gutters, its storage, and its reuse, thus limiting the harmful environmental effects of runoff onto the ground. In its version implementing the BOX, it also allows for the complete inverting of the photovoltaic unit, which then exposes the metal face of the BOX to the elements (hail) and protects the PV array from mechanical damage. The process can also be equipped with an integrated windbreak system and / or a light reflector to improve the illumination of the panels located opposite it.

Description

Title of the invention: SINGLE-AXIS GRAVITY-DRIVEN TRACKING METHOD FOR ALL TYPES OF PHOTOVOLTAIC PANELS FIELD OF INVENTION

[0001] The invention consists of a solar tracker designed to support any type of photovoltaic (PV) panel, regardless of its shape, dimensions, and the nature of its components, by improving its efficiency through its ability to follow the sun's path along an axis, for example, from east to west (northern hemisphere), for optimized exposure to solar radiation. DRAWINGS

[0002] [Fig. 1] Side view of the tracker: A tracker carrying only photovoltaic panels, B tracker carrying photovoltaic panels in combination with a BOX (patent application no. FR2310044)

[0003] [Fig.2] Front view of the tracker carrying PVs in tandem with the BOX

[0004] [Fig.3] Front view of a stand supporting 15 PV and BOX duos.

[0005] [Fig.4] Side view of a stand supporting 15 PV and BOX duos STATE OF THE ART

[0006] Direct solar radiation accounts for 90% of the energy supplied by the light beam. The power loss along the north / south axis does not exceed 1% up to an angle of 8°, but can reach 8% in the morning and evening at an angle of 23°, while this loss can reach 75% along the east / west axis at the same times and angles. The Earth rotates around the sun and on its own axis, but its axis of rotation is deviated by 23.27° from the plane of its revolution around the sun. Consequently, the declination angle between solar radiation and the ground varies daily and at every time of day. According to the double zenith and azimuthal coordinate system, the horizon is the reference plane on which two variables are defined: azimuth and altitude. The origin of the azimuths is fixed at the South and then counted from 0 to 360° clockwise; the mounting of the tracking methods that results from this is called altazimuthal.The origin of altitudes is fixed on the horizon and measured from 0 to 90° rising towards the zenith. Deriving from the principle of the heliostat, the solar tracker is a device that orients the payload (the photovoltaic unit) towards the sun so that its rays are presented at the optimum angle, knowing that the observed brightness of an object is proportional to the cosine of the angle of incidence of the light that strikes it.

[0007] Solar tracking systems can be equipped with an electronic astronomical control module that guides the tracker throughout the day, seeking to ensure the most efficient illumination of the PV array. Scientific literature reports productivity gains of approximately 22% to 30% for single-axis processes compared to fixed installations.

[0008] As a matter of current technology, existing single-axis units are primarily driven by geared motors combining a gearbox and an electric motor. Given the high torque requirement due to the inertia of the moving mass, these systems consume approximately 40 kWh of electricity per kW produced. In all cases, they suffer from significant mass, considerable technical complexity (reduction systems, linkages, motors, gears, etc.) leading to failures of various origins, high production, installation, and maintenance costs, and a limited lifespan (10,000 to 20,000 hours for the most efficient geared motors), which reduces their advantages compared to fixed-tilt panel supports.

[0009] To overcome these drawbacks, some devices use a low-boiling-point compressed gas fluid whose movement from one side to the other is driven by solar heat, which creates gas pressure that causes the tracker to move in response to the resulting imbalance. While this method solves some of the problems raised by conventional systems by partially reducing material requirements, it loses much of its appeal because it requires sufficiently long exposure to sunlight in the morning to preheat the process and must interrupt its cycle early in the evening, precisely when the benefit of tracking is at its maximum.

[0010] The best system is one which, operational from the appearance of the sun, and without its support to function, allows, throughout the day, its tracking at the lowest cost of manufacture, installation and operation, consuming a minimum of energy and reducing the effects of shadow cast, and the risks of breakdowns or mechanical incidents.

[0011] The literature indicates that, although solar tracker modules are complex and expensive devices requiring frequent maintenance and repairs, their contribution is crucial, but they are not suitable for widespread use. The object of the invention is to solve this seemingly impossible problem by making trackers technically and economically accessible to all installations, even those not connected to the grid, particularly in isolated areas where efficiency is even more critical. Summary of the invention

[0012] The invention is a solar tracker which differs from all other existing single-axis tracking systems in that the process on which the oscillations of the photovoltaic block are based is based on a simple mass transfer generated by the circulation of a fluid and requires only a pump to activate the fluid and no geared motor.

[0013] The tracker, which is the subject of the patent, allows the PV to be repositioned sequentially at time intervals defined by the user and according to the chosen azimuth angle.

[0014] The invention, which is designed for PV carriers, can also support tandems formed of a PV and the SOneBOX system (patent application no. FR2310044) intended to capture the low heat (waste heat) produced on the underside of the PV, for its valorization, for example, in the form of electrical energy to be added to the intrinsic production of the panels.

[0015] The BOX then integrates with the photovoltaic block and follows its movements.

[0016] The invention improves the efficiency of the tandem process in the same proportion that it improves the yield of PV alone.

[0017] The invention, which does not involve significant earthworks, is based on two vertical supports, reinforced or not, positioned on either side of the photovoltaic unit. The supports also carry the means that are not connected to the photovoltaic unit and are themselves fixed to the medium on which they are installed (ground, roof, dedicated structure) mechanically, by gluing or by ballasting.

[0018] Protection against wind pressure is ensured by flattening the PV array and locking it in place with an indexing pin, but the tracker can also be equipped with windbreaks. The effects of snow load are countered by the control processor, which commands the panels to tilt so they can shed the snow. When the tracker is used with a PV array and a BOX, and in a specific operating mode, the photovoltaic unit can rotate 180° to provide the PV array with weather protection, particularly against hail, since the exposed face is then that of the BOX, which is metallic.

[0019] The mechanisms are modular and fully automated, very easy to install, require very little maintenance, and consume very little electrical energy. These characteristics give the invention a long lifespan and guarantee high PV efficiency without requiring an unreasonable investment, disproportionate monitoring or maintenance, and while preserving simplicity of packaging, transport, and installation. The invention minimizes environmental impact (harm to flora and fauna, noise, erosion, soil covering and shading) by proposing the use of recyclable and / or bio-based materials and, in certain Configurations and positioning: gutters for the conservation and recycling of satellite or washing water. Finally, in other configurations, deflectors improve exposure to diffuse radiation and to that resulting from the albedo of the panels arranged opposite each other.

[0020] DETAILED DESCRIPTION OF PREFERRED EMBODIMENT MODES

[0021] According to a first feature, the invention [Fig.1] (front view) and [Fig.2] (side view) consists in the realization of a means of tracking (tracker) solar radiation to ensure the perfect illumination of photovoltaic (PV) panels whatever they may be and whatever their conformation [Fig.1] (A) (1).

[0022] According to a second feature, the tracking means can also be assigned to the pair formed by a PV and a BOX [Fig.1](B) (1) and (2)(patent application no. FR2310044), the PV and the BOX are then clamped by compression using clamp-type fixings.

[0023] According to a third feature, the method comprises two cylindrical tubes (6) placed at each end of the beam. Each of the two tubes is attached, by means of a bearing support (7), to one of the two feet (24) supporting all the elements of the tracker, which makes the photovoltaic block free to pivot about the axis (26).

[0024] According to a fourth feature, a beam made of a parallelepiped metal tube (5) is positioned on the movable axes to which it is connected and which it envelops to pivot with them.

[0025] According to a fifth feature, two stringers (3) are arranged perpendicular to the beam under the PV (or under the PV and directly above the BOX, which is then attached to the stringer by self-drilling screws or rivets) and are connected to it by at least four clamp-type fasteners (4) (Divisional Application No. 1 of Patent No. FR2310044), but the connection between the elements can be made by means of any ad hoc connection system available on the market if it meets the requirements of this patent. Attached to the stringers, on either side of the axis of rotation, are two independent, sealed boxes connected to a pump by a network of pipes equipped with rotary joints, which allows the circulation of a liquid fluid from one box to the other, thus enabling the tilting of the photovoltaic unit for the sole benefit of transferring the corresponding masses.

[0026] According to a sixth feature, the device, as described, forms the photovoltaic unit which is equipped with a tilting motion by simple advection, according to a programmed cycle, of a liquid fluid, preferably demineralized water, containing antifreeze, and treated bacteriologically. The fluid is supplied in two sealed tanks (10), independent of each other, in which a vacuum can be created. The fluid is stored (28) as close as possible to the circulation pump which ensures its distribution to each of the tanks (11).

[0027] According to a seventh characteristic, the boxes are duly dimensioned according to the angular momentum determined by the product of the moment of inertia and the rotational speed, specifically measured according to the conformation of the system (mass and dimensions of the photovoltaic block, parameters of the transfer network, power of the pump), the specified requirements (duration of the replacement time, angular velocity, exposure time), the number of vents available and their spacing.

[0028] According to an eighth feature, each box is placed on brackets screwed to the stringer, on either side of the axis of rotation, generally at the point furthest from the center of gravity of the photovoltaic block.

[0029] According to a ninth feature, at one end of the shaft, near one of the bearings and beyond it, a corolla (8) is arranged, supported by a guide and support flange (27), preferably made of steel. The corolla is pierced with vents (9) aligned one above the other so as to accommodate, as the corolla rotates under the effect of the pivoting of the photovoltaic block, the inserting pins of the indexing fingers (16 and 17). The corolla completely encloses the cylindrical tube.

[0030] According to a tenth feature, the vents are arranged so that, for each perforation, there is a corresponding angle of inclination of the photovoltaic block for its optimal exposure to radiation during the circumvolution of the sun, at point 0, the photovoltaic block is flat and centered so that the masses are balanced around the axis.

[0031] According to an eleventh feature, the transport of the fluid from one to the other of the boxes is carried out by means of a metering pump, self-priming or not (11), electrically powered, equipped with a rotary joint (12) specifically designed to allow the passage of liquid between two volumes, one of which is in motion and the other remains fixed, which allows the fluid distribution circuit (13) to follow the oscillations of the photovoltaic block without being impacted by the movement.

[0032] According to a twelfth characteristic, the fluid distribution circuit consists of a metallic or PVC piping and includes, at its end, at the connection with the photovoltaic block, a rotating joint which allows the transfer of the fluid to the box for which it is intended.

[0033] According to a thirteenth feature, the volume of fluid transferred at each stage is calibrated according to the angle of inclination to be achieved. The stress exerted by the fluid transfer causes the photovoltaic block to tilt, pivoting around its axis until it reaches the desired angle.

[0034] According to a fourteenth characteristic, two laser triangulation displacement sensors (14), two cameras or any other equivalent devices are placed on the foot, on each side, as close as possible and directly to the corolla whose course they follow by calibration on the vent line to determine the precise moment when the photovoltaic block must be immobilized.

[0035] According to a fifteenth feature, two indexing fingers, preferably spring-loaded with pneumatic or electrical pulse return (16 and 17), are positioned on the base, on each side, as close as possible to and directly opposite the corolla, whose movement they track by calibration along the vent line. Informed by the sensor, they are actuated by the control software at the instant the photovoltaic unit, having reached the required angle, presents the corresponding vent. Each indexing finger then releases a locking pin which enters the vent opposite it, thus immobilizing the photovoltaic unit.

[0036] According to a sixteenth feature, the indexing fingers are doubled to ensure the operation of the process in the event of a defect in one of them (29 and 30).

[0037] According to a seventeenth feature, the position of the indexing finger is transmitted to the control and monitoring unit. Each movement of the indexing finger is controlled by the general control software, but this control can be taken over, automatically or physically, at any time by the system or by an operator as part of a degraded operating procedure or alert.

[0038] According to an eighteenth feature, when the SUNeBOX hot air capture process is implemented (patent application no. FR2310044), the hot air is extracted by depressurization, then transferred inside the beam through one or more ducts, equipped with a sleeve, positioned at the junction of the BOX and the beam, allowing the heat transfer fluid to be evacuated towards the beam, then through the cylindrical tube (15).

[0039] According to a nineteenth feature, the beam and the cylindrical tube being under depression, the hot air is extracted and directed to the transport network through a rotary type joint specifically adapted to gaseous fluids, which allows it to accompany the movements of the photovoltaic block (18).

[0040] According to a twentieth feature, after passing through a check valve (19) (25), the hot air flow is directed, by overpressure, through a network (20), to one or more manifolds (21) and then transferred either to the phase change material storage process or to the hot air-to-electricity conversion process.

[0041] According to a twenty-first feature, the electrical cables (22) necessary for the transport of the electricity produced by the PV are routed, passing through the beam, then through the cylindrical tube opposite to the one where the hot air is evacuated, to a rotating joint (23) specifically adapted for the passage of the wires.

[0042] According to a twenty-second feature, the two feet (24) placed under the bearings, on either side of the photovoltaic block, are composed of cylindrical or parallelepiped steel tubes, with or without lateral or central reinforcement.

[0043] According to a twenty-third feature, one of the feet is equipped with carrying means allowing the indexing fingers (male part), the LASER (or camera), the pump equipped with the rotary joint and the fluid storage tank to be positioned there.

[0044] According to a twenty-fourth feature, one or more aprons fixed on the feet provide, when necessary, support for all the equipment related to the operation of the PV and the BOX, such as inverters, micro-inverters, cabinets, concentrators, monitoring systems, transformers, converters, sensors, detectors, maintenance or servicing mechanisms, cable trays, piping and ballast means.

[0045] According to a twenty-fifth feature, in order to share all or part of the utilities, in particular the fluid storage unit, the pump and the compressor, if applicable, the tracker as defined by the invention can support, arranged on the beam in landscape or portrait orientation [Fig. 3], a single PV or several PVs. Similarly, the stringers can be dimensioned so that a single beam supports several rows of PVs. Finally, several trackers can be installed side by side and jointly benefit from the centralized utilities.

[0046] According to a twenty-sixth feature, the system is controlled and operated by means of software. The software is equipped to determine the optimal solar radiation exposure of the PV arrays daily and at any given time, for example, through an open-loop, closed-loop, or mixed-loop algorithm using feedback from a solar position sensor, enabling it to achieve an absolute accuracy of less than 0.025. The software is also fed with data provided by the indexing finger transmitter, the laser triangulation displacement sensor, an anemometer, a pyranometer, and, if the BOX (patent application no. FR2310044) is used, all the information from the BOX's control and monitoring devices (temperature, humidity, etc.).These methods, by measuring diffuse and reflected global solar radiation, allow for adjustment of equipment calibration, taking into account the orographic influence of clouds. The software transmits the data to the autopilot and the monitoring station, which can be delegated, along with the necessary recalibrations and the order to enter a safe position when the wind level monitored by the anemometer or the snow mass exceeds the set limit(s).

[0047] MANNER IN WHICH THE INVENTION IS CAPABLE OF INDUSTRIAL APPLICATION

[0048] The productivity gain from tracking the sun's path to ensure optimal illumination is well-known and documented. For single-axis trackers, this gain is on the order of 25% to 40%, depending on the time of day, compared to fixed panels. Numerous systems exist. The present invention differs from all other similar methods in that it uses gravitational force to perform the translational movements currently generated mechanically. This principle reduces energy consumption (less than 0.2% of the energy produced by the PV system, compared to 3% to 5% for other tracking systems) and the necessary maintenance, which is further facilitated by the removable components and their replacement for workshop repairs.

[0049] The operating principle of the tracker is totally innovative since it operates by simple mass transfer orchestrated by the office of a corolla whose immobilization system, controlled by specific software, offers the photovoltaic block a sufficiently wide range of inclinations to optimally cover the field offered by more expensive continuous trackers.

[0050] The invention enables the recovery of rainwater and wash water. This device, present in certain fixed-panel photovoltaic systems, is absent from all single-axis tracking systems. This means reduces soil erosion due to runoff in the vicinity of the PV panels and constitutes a significant environmental advantage. Furthermore, the collected water can be used in the process described in patent application no. FR2310044 if implemented; it can also be used in agriculture or as a raw material for the by-products proposed by said patent.

[0051] The invention may include, on the underside of the photovoltaic block, an articulated or non-articulated deflector allowing the reflection of diffuse or direct illumination towards the opposite PV, which improves the productivity of the network by 5 to 12%.

[0052] Economically, it is reported that the additional cost due to the installation of a tracker represents, on average, 26% of the total investment, while maintenance expenses can double. The innovation, through its simple design and the resulting ease of installation, significantly reduces this impact while offering ingenious means of adapting each panel to site constraints, for example, in mountainous or sloping terrain, as well as to variations in ground level, minimizing the need for trenching or specific leveling work.

[0053] In its design the invention allows the positioning, in portrait or landscape, on the same support of several photovoltaic panels and the chaining, side by side of several groups of supports, allowing the pooling of utilities (pump, fluid storage unit, corolla, rotary joints) and their optimization.

[0054] The invention is autonomous, as it does not depend in any way on external equipment, since, when implemented with a PV or with a PV and BOX coupling, it offers all the elements that make it independent of existing systems (BOX, mounting profile with satellite water recovery, fixings). But the invention can be used, alone or with the BOX, in conjunction with all types of PV, most fixing systems, including weld-on-waterproof systems, and all rails or profiles. This makes it universal. POSSIBLE VARIATIONS

[0055] The invention is not limited to the embodiments described above. Numerous versions are conceivable within the scope of the stated claims. Modifications may relate to the nature of the materials of the various components or the methods of connection between the elements. These may include control or servo systems, or the configuration of the transmissions. Similarly, fluid storage and movement can be ensured in the adapted side members. All variations that do not constitute an essential difference from the present invention are permitted.

Claims

Demands

1. Single-axis solar radiation tracking device [Fig 1] enabling photovoltaic panels(1) to follow the sun's path optimally by transferring a captive liquid mass, structured around a movable axis, called a beam, embedded in a bearing bearing(7) placed on a foot(24), composed of a parallelepiped tube(5) in which is embedded, at each end, a cylindrical tube(6) carrying, on one of them, supported by a guide and support flange(27), a corolla(8) pierced with vents(9), intended to receive two immobilizing pins from indexing fingers(16,17,29 and30).

2. Device according to claim 1 characterized in that it forms an assembly linking the photovoltaic panels to two stringers(3) by at least four clamp-type fixings(4).

3. Device according to claims 1 and 2 characterized in that, fixed to the longitudinal members(3), and offset to the ends of the rows of photovoltaic panels carried by the chassis, are arranged, on either side of the axis of rotation(26), mass transfer tanks composed of sealed and independent boxes(10), connected to a pump(11) by a network of pipes equipped with rotary joints(12) forming a distribution circuit(13) intended for the circulation, from one to the other of the boxes, of a liquid fluid, which allows the tilting of the photovoltaic block for the sole benefit of the transfer of the corresponding masses and allows it to carry out the movements necessary to optimize its exposure to solar radiation.

4. Device according to claims 1 to 3 characterized in that a corolla (8) is welded onto one of the cylindrical tubes (6) completely enveloping it. The corolla is pierced with vents (9) which allow, when the tilting of the photovoltaic block, at the required angle, to present a vent in front of an indexing finger, and on command from the operating system, then controlled by a laser or a camera (14), a pin carried by the spring-loaded indexing fingers with return by pneumatic effect or electrical impulse (16 and 17) to penetrate it, in order to ensure the immobilization of the photovoltaic block and its firm holding in the required position until a new command releases it to perform a new movement.

5. Device according to claims 1 to 4 consisting of an electric pump(11) and a storage tank(28) positioned outside the photovoltaic block, which allow the movement of the fluid and its distribution or withdrawal into, or from, the mass transfer tanks by means of pipes equipped with rotary joints.

6. Device according to claims 1 to 5 characterized in that a network, wired or wireless, ensures the transmission of data relating to the measurements recorded and the actions taken by the laser triangulation displacement sensor, the indexing fingers, the pump and the peripheral equipment intended to collect the parameters necessary for the operation of the tracker to a control and command software specifically dedicated to the process.

7. Device according to claims 1 to 6 characterized in that a BOX[Fig.1](B)(2)(patent application no. FR2310044), for the recovery and optimization of calories carried by the hot air produced under the PV, can be intercalated between the PV and the chassis.

8. The device according to claim 7, characterized in that the means for extracting the hot air captured by the BOX, when in operation, consists of a duct (15) at the junction of the BOX and the beam, allowing the heat transfer fluid to be evacuated towards the beam, then through the cylindrical tube and a rotary joint (18), beyond a check valve (19) (25), to the transport network (20) formed of collectors (21) for its recovery. The electrical cables (22) providing the connection between the PV panels and the inverters for the transmission of the generated current are routed through the beam and the cylindrical tube to a suitable rotary joint (23).

9. Device according to claims 1 to 8 characterized in that two feet [Fig 3] and [Fig 4] can carry several PV arranged in portrait or landscape orientations by implementing only one tracking system.

10. Device according to claims 1 to 9 characterized in that groups of trackers carrying several PVs can allow the pooling of certain components such as the corolla(8), the rotary joints(12,18 and 23) the pump(11) and the storage tank(28).

11. Device according to claims 1 to 10 characterized in that the control of the movements of the photovoltaic blocks, the control and monitoring of the installation are ensured by means of software The specific method is based, for example, on a loop algorithm assisted by a solar position sensor, amended with information and data provided by the specific software and measuring devices. The method regulates the fluid flow between the cells by determining when the indexing finger should command the spindle to enter the vent presented to it, to then transfer, into one of the two transfer tanks, the necessary quantity of fluid to tilt the photovoltaic block to one side or the other according to the requirements calculated to achieve the optimum tilt angle.

Images