Device for cleaning solar panels using ionic wind combined with electrostatic force

Abstract

The invention relates to a device for cleaning solar panels (1), the principle of which is based on an ionic wind combined with an electrostatic force which are applied simultaneously to the dust particles. The device consists of a plasma actuator attached to a wheeled vehicle (9) on the surface of the panel (1). The plasma actuator comprises three electrodes: an ionising electrode (2), an earthed electrode (3) and a static electrode (4). Both the ionising electrode (2) and the static electrode (4) are supplied with the same electric voltage of about twenty kilovolts. The static electrode (4) is a cylindrical tube that applies an electric field so as to detach the dust particles from the surface of the panel (1) by means of an electric attractive force. The assembly made up of the ionising electrode (2) and the earthed electrode (3) produces an ionic wind that easily cleans the dust particles previously lifted by the static electrode (4).

Description

[0001] PATENT FOR INVENTION

[0002] Applicant: Djillali Liabes University, Sidi-Bel-Abbès

[0003] Title of the invention:

[0004] "Solar panel cleaning device using ionic wind combined with electrostatic force"

[0005] DESCRIPTIVE MEMOIR Patent Title:

[0006] Solar panel cleaning device using ionic wind combined with electrostatic force

[0007] Technical field to which the invention relates:

[0008] The technical field to which the present invention relates concerns the field of renewable energy using solar panels. The main objective of this invention is to counteract the accumulation of dust and other particles on the surfaces of solar panels, a common problem that significantly reduces their efficiency in converting solar energy into electrical energy. The invention relates to a device for cleaning solar panels using an artificial wind, called an "ionic wind," electrically generated by a plasma produced between two electrodes, combined with an "electrostatic force" applied to the dust particles, which is produced by a third electrode.

[0009] Prior art:

[0010] Photovoltaic installations represent clean energy production using solar panels that must be regularly cleaned to achieve optimal efficiency. Constant soiling caused by environmental factors such as dust, bee pollen, and moss reduces the performance and efficiency of the solar panel.

[0011] The methods used to clean solar panels are numerous and rely on the following techniques: Natural methods where rain and wind are used as natural agents to clean the panel surface. The drawback of this method is that these two natural elements are unpredictable. Using an air conditioning system with built-in ventilation to remove accumulated dust. This method seems quite promising, but it remains rather expensive. Using high-pressure water jets to remove accumulated dust. In addition to its relatively high cost due to the high-pressure pumps, the use of large quantities of water with chemical abrasives causes surface degradation. Coating the panel with a film made of a special material that promotes dust sloughing; however, this method also requires water.The mobile wave method remains quite interesting in terms of laboratory efficiency, but it has the drawback of using electrodes traced on the panel surface. Furthermore, it has not yet been tested on a full scale.

[0012] Previous research on solar panel cleaning has explored the use of electrostatic forces, while other studies have experimented with the use of ionic wind (see references below). Our innovative approach combines both by simultaneously employing ionic wind and electrostatic force. Kawamoto, H., & Shibata, T. (2015). Electrostatic cleaning system for removal of sand from solar panels. Journal of Electrostatics, 73, 65-70.

[0013] Altmtaç, M., & Arslan, S. (2021). The study of dust removal using electrostatic cleaning system for solar panels. Sustainability, 13(16), 9454.

[0014] Abd-Elhady, M. S., Ali, A. R., Singh, R. P., Ibrahim, M., & Kandil, H. A. (2023). A new approach of electrostatic cleaning for removing dust from solar panels. Journal of Engineering Science and Sustainable Industrial Technology, 1(1), 22-29.

[0015] Tilmatine, A., Kadous, N., Yanallah, K., Bellebna, Y., Bendaoudi, Z., & Zouaghi, A. (2023). Experimental investigation of a new solar panels cleaning system using ionic wind produced by corona discharge. Journal of Electrostatics, 124, 103827.

[0016] Kadous, N., Yanallah, K., Bellebna, Y., Bendaoudi, Z., & Tilmatine, A. (2024). Exploring the effectiveness of a novel cleaning method for solar panels using corona ionic wind. Particulate Science and Technology, 42(2), 324-330.

[0017] But de invention:

[0018] The aim of the invention is a new technique for cleaning solar panels without contact with the surface, without the use of water or wiping with a broom. The process consists of an artificial wind called "ionic wind" using an electric actuator with plasma produced by an electrical discharge called "corona discharge," combined with an "electrostatic force" applied to the dust particles.

[0019] The electrostatic force is produced by an electrode, called a "static electrode," whose role is to detach particles from the panel surface to facilitate cleaning by the ionic wind. The ionic wind is electrically generated by a discharge called a "corona discharge," using a system composed of two types of electrodes: an "ionizing electrode" and a "ground electrode," which consists of two or more metal tubes connected to earth.

[0020] Description of the figures:

[0021] The invention will be well understood with the aid of the following description, with reference to the attached schematic drawings, representing by way of non-limiting example embodiments of the device as well as the operating principle of this method.

[0022] Figure 1: Descriptive drawing of the plasma actuator (view with walls)

[0023] Figure 1: Descriptive drawing of the plasma actuator (view without walls)

[0024] Figure 3: Descriptive drawing of the spiked ionizing electrode

[0025] Figure 4: Descriptive drawing of the ionizing electrode with a taut fine wire

[0026] Figure 5: Descriptive drawing of the blade ionizing electrode

[0027] Figure 6: Descriptive drawing of the saw-blade ionizing electrode

[0028] Figure 7: Overall descriptive drawing of the solar panel cleaning device

[0029] Figure 8: Descriptive drawing of the curved aerodynamic actuator. Presentation of the invention and embodiment:

[0030] The actuator is rectangular in shape, a few centimeters wide and high, and its length matches that of the solar panel. It comprises two essential parts: the ionizing section and the electrostatic section. The ionizing section houses the ionizing electrode and the grounded metal tubes. Air enters through the open upper wall, and the generated ionic wind exits through the open lower wall facing the solar panel, via the space between the grounded tubes. The electrostatic section, with its open lower and front walls, houses the static electrode, which exerts an attractive force on the dust particles. The other walls of the actuator are closed, preventing dust from passing back through them.

[0031] The actuator is a device comprising an ionizing electrode connected to a high voltage (2), a ground electrode connected to earth consisting of two or more metal tubes (3), and a static electrode (4) (Figs. 1 and 2). The ionizing electrode consists of either metal points (5) with a very small radius of curvature (Figure 3), a thin metal wire (6) (Figure 4), a sharpened blade (7) (Figure 5), or a saw blade (8) (Figure 6). The ground electrode consists of two electrically connected metal tubes (3) spaced approximately one centimeter apart, located below the ionizing electrode at a distance of approximately one to three centimeters.

[0032] The static electrode (4) which is used to detach dust particles from the surface of the solar panel by applying an electrostatic force, is a cylindrical metal tube located at the front of the actuator just at the exit of the ionic wind.

[0033] After the application of a high direct or alternating voltage, the ionizing electrode (2) ionizes the surrounding air with its strong electric field, resulting in the creation of positive and negative electric charges. The movement of these charges induces the creation of an ionic wind. The movement of electric charges under the influence of the intense electric field produced by the ionizing electrode thus causes the formation of an artificial wind, called an "ionic wind." When charged air molecules are subjected to an electric field, they are accelerated. When these charged molecules collide with neutral molecules, they transfer some of their kinetic energy, resulting in an air movement known as an ionic wind.

[0034] This ionic wind, which is more or less strong, depends on the geometric configuration of the actuator, the distance between the ionizing electrode and the electrode connected to earth, as well as the value of the high voltage applied.

[0035] The static electrode (4), which plays a crucial role, applies an attractive force to dust particles. These particles are lifted by this force and then easily dispersed by the ionic wind, thus avoiding the forces that hold the particles to the surface, such as friction and Van der Vav 11. When the static electrode approaches the particles, they become charged, either by electrostatic induction if they are electrically conductive or by dielectric polarization if they are insulators, with a charge opposite in sign to the potential of the static electrode. This results in an attractive force that draws the particles towards the static electrode, causing them to detach from the surface of the solar panel and greatly facilitating their movement by the ionic wind.Another advantage of using this static electrode is the reduction in power required to clean the surface of the solar panel. Indeed, if dust particles can be detached with the static electrode, it is no longer necessary to generate an intense ionic wind with greater energy consumption.

[0036] The actuator, which spans the entire width of the panel, is attached to a rolling vehicle (9) moving across the panel surface at an average linear speed of approximately 1 cm / second (Fig. 7). The vehicle has lateral wheels (10) and a spring-loaded fastening system that ensures it adheres firmly to the solar panel and prevents it from detaching. Thanks to the ionic wind generated on the panel surface and the electrostatic force that lifts dust particles, the moving actuator moves the dust along the panel's longitudinal axis. This broom-like motion of the actuator ensures cleaning without contact with the panel surface. Upon reaching the end of the panel, the actuator stops and is either withdrawn or driven back to its initial position. The actuator can then be restarted to perform a second pass if necessary and clean any remaining dust.

[0037] Made of lightweight plastic, the actuator allows for the attachment of the ionizing electrode, the two grounding tubes, and the static electrode. The plastic material's ability to provide high-voltage electrical insulation is crucial, as the ionizing and static electrodes must be electrically connected at a high voltage of approximately 20 kilovolts and therefore must be well insulated from the two grounding tubes.

[0038] The device operates with a rechargeable battery that simultaneously powers the high-voltage power supply and the vehicle's wheel drive motors. The high-voltage power supply enables the actuator to generate ionic wind through the voltage applied between the ionizing electrode and the two tubes, while simultaneously allowing the static electrode to apply an attractive force to lift dust particles. The battery and high-voltage power supply are housed inside the vehicle's cabin.

[0039] The electrical power required for the high-voltage supply and operation of the motors is approximately 100 Watts, energy stored in the battery which can be drawn directly from the solar panel itself.

[0040] Another option for the actuator design involves a curved, aerodynamic device with an opening 2 cm wide at the top and approximately 1 cm at the bottom (Fig. 8). The ionizing electrode, which can be a wire, a blade, or a saw blade (2), is located in the upper part, while the grounding electrode takes the form of two rectangular plates positioned in the lower part (12). This configuration allows the device to generate a horizontal airflow relative to the surface of the solar panel, thus optimizing dust removal efficiency. A static electrode is attached to the outlet of this actuator to lift the particles and facilitate their removal by the outgoing ionic wind.

[0041] Other documents are incorporated by reference in this document:

[0042] 1) Patent 1: WO 2017153898A1

[0043] 2) Patent 2: US 7999173 B1

[0044] 3) Publications 18i2: Publication 1 : Tilmatine, A., Kadous, N., Yanallah, K., Bellebna, Y., Bendaoudi, Z., & Zouaghi, A. (2023). Experimental investigation of a new solar panels cleaning system using ionic wind produced by corona discharge. Journal of Electrostatics, 124, 103827.

[0045] Publication 2 : Kadous, N., Yanallah, K., Bellebna, Y., Bendaoudi, Z., & Tilmatine, A. (2024). Exploring the effectiveness of a novel cleaning method for solar panels using corona ionic wind. Particulate Science and Technology, 42(2), 324-330.

[0046] 4) Brevet WO2020251949A1 et Publication scientifique 3 :

[0047] Publication 3: Sreedath Panat and Kripa K. Varanasi (2022). Electrostatic dust removal using adsorbed moisture-assisted charge induction for sustainable operation of solar panels. Sci. Adv., 8 (10), eabm0078.

[0048] Below are some comments to show the points of difference with these references.

[0049] 1) Reference WO2017153898A1

[0050] The cleaning technique presented in this reference is based on the use of an alternating current (AC) corona discharge, employing a ground electrode consisting of a cylindrical tube facing the path of the airflow, which follows a trajectory parallel to the surface to be cleaned. Furthermore, this patent does not incorporate the electrostatic force that lifts the particles.

[0051] In our case, we use a corona discharge system with alternating current (AC) or direct current (DC) and a ground electrode consisting of two or more metal tubes. Wind blows perpendicularly to the panel surface, passing through the gap between the metal tubes. Additionally, a static electrode dislodges particles from the surface, making cleaning easier. Our configuration allows the wind to flow freely, unlike in reference 1 where the electrode obstructs the airflow, causing it to impact directly on the tube and thus diverge. Furthermore, and most importantly, our static electrode facilitates cleaning by dislodging the particles.

[0052] On the other hand, the plasma actuator in our case can also take the form of a curved aerodynamic element, having an opening of about two centimeters (2 cm) wide at its upper end and approximately one centimeter (1 cm) wide at its lower end (Fig. 8), with the association of another electrode connected to the high voltage to facilitate the detachment of particles.

[0053] 2) US Reference 7999173 B1

[0054] The cleaning technique presented in this reference is based on the use of a surface plasma produced by another type of discharge called a Dielectric Barrier Discharge (DBD), which is necessarily powered by alternating current (AC). In our case, however, we use a volumetric plasma produced by a corona discharge in alternating current (AC) or direct current (DC), which is completely different from the DBD type discharge. Furthermore, this reference does not use an additional static electrode, as in our case, to detach the particles, thus making cleaning easier.

[0055] 3) For scientific publications 1 and 2:

[0056] For these two references, there are four important differences, which are as follows:

[0057] For both of these models, cleaning is carried out solely by ionic wind without the application of an electrostatic force on the dust particles.

[0058] The ground electrode consists of a metal frame connected to the earth, whereas in the case of our patent it is a ground electrode formed by two or more parallel metal tubes.

[0059] Another difference lies in the fact that, in our patent, the device comprises the plasma actuator and a rolling vehicle to which the actuator is attached. Whereas in these two references, the actuator and the vehicle form a single device.

[0060] The plasma actuator in our case can take the form of a curved aerodynamic element, with an opening approximately two centimeters (2 cm) wide at its upper end and approximately one centimeter (1 cm) wide at its lower end (Fig. 8). The configuration is designed to generate a horizontal airflow relative to the surface of a solar panel and thus improve dust removal efficiency.

[0061] 4) Patent WO2020251949A1 and Scientific Publication 3:

[0062] Unlike our patent, the two references cited here rely on an electrostatic induction force to dislodge dust particles without the application of an ionic wind. A first pass of the electrode, positively or negatively charged, electrically charges the particles. A second pass, with the opposite polarity, causes them to detach from the panel surface and be collected, but without the application of an ionic wind.

[0063] Furthermore, for our patent, a different type of attractive force is applied to the particles. The particles acquire a charge by electrostatic induction if they are electrically conductive, or a charge by dielectric polarization if they are insulators. The force is applied instantaneously, precisely at the moment the particles are charged by electrostatic induction (or by electrical polarization).

Claims

DEMANDS 1. A solar panel cleaning device comprising a plasma actuator configured to simultaneously generate an ionic wind and an electrostatic field, said actuator comprising: - an ionizing electrode to generate an ionic wind - a grounded electrode - a static electrode positioned at the front to detach particles from the surface of the solar panel; - a high-voltage power source operationally connected to the ionizing electrode and the static electrode; - a mobile vehicle adapted to move along the surface of a solar panel in order to clean accumulated dust, said vehicle further comprising an electric battery.

2. The solar panel cleaning device according to claim 1 is characterized in that it comprises a plasma actuator consisting of two separate sections. The ionization section, which consists of an ionizing electrode and two or more grounded metal tubes, generates an ionic wind. A separate electrostatic section, placed in front of the ionization section, which is composed of a static electrode, whose role is to produce a non-ionizing electrostatic field.

3. The solar panel cleaning device according to claim 1 is characterized in that the static electrode exerts an attractive electrostatic force on the solar dust particles, facilitating their detachment from the surface of the panel and thus promoting easy and efficient cleaning by ionic wind.

4. The plasma actuator referred to in claim 1 is characterized in that the static electrode has a rounded shape. This configuration attenuates the intensification of the electric field, thus promoting efficient detachment of dust particles from the surface of the solar panel while preventing the generation of unwanted electrical discharges.

5. The plasma actuator referred to in claim 1 is characterized in that the static electrode is configured to apply a moderate electrostatic detachment force to dust particles on the surface of the solar panel. This force is calibrated to facilitate the detachment of the particles from the surface, allowing their subsequent removal by the ionic wind, while avoiding excessive force that could lead to the complete lifting or re-adherence of the particles.

6. The solar panel cleaning device according to claim 1 is characterized in that the ionization section defined in claim 2 comprises two open walls: the upper wall serving as an air inlet and the lower wall oriented towards the surface of the solar panel, allowing the generated ionic wind to flow towards the panel. The other walls are closed.

7. The solar panel cleaning device according to claim 1 is characterized in that the electrostatic section defined in claim 2 comprises two open walls: the bottom wall and the front wall to allow the static electrode to exert an attractive electrostatic force on the dust particles on the surface of the solar panel.

8. The plasma actuator referred to in claim 1 is characterized in that the ionizing electrode and the static electrode are supplied by a high DC or AC voltage of approximately twenty kilovolts. This voltage may come from the same power source or from two different sources.

9. The cleaning device according to claim 1 is characterized in that the battery, the high-voltage power source and the stepper motor are mounted inside the compartment of the moving vehicle.

10. The plasma actuator referred to in claim 1 is characterized in that it has a parallelepiped shape and is constructed with walls made of insulating plastic material. The choice of plastic is dictated by the need to ensure electrical insulation between the ionizing electrode and the static electrode, which have a potential of approximately twenty kilovolts, and the grounding electrode. The three electrodes are mounted and fixed to the plastic walls.

11. The plasma actuator referred to in claim 1 is characterized in that all its walls are made of plastic. The choice of a plastic material, which is electrically insulating, as opposed to a conductive material, avoids altering the distribution of the electric field lines, thus ensuring optimal cleaning performance.

12. The plasma actuator referred to in claim 1 is characterized in that the ionizing electrode is made up of either metal tips with a very small radius of curvature, or a thin, taut metal wire, or a sharp blade or a saw blade.

13. The plasma actuator referred to in claim 1 is characterized in that the ionizing electrode is fixed to a metal tube which acts as an electrostatic screen to improve the distribution of electric field lines.

14. The plasma actuator referred to in claim 1 is characterized in that the grounded electrode comprises two or more parallel metal tubes, each having a diameter of approximately 1 cm, positioned parallel to the ionizing electrode. These tubes are arranged parallel to the surface of the solar panel and maintained at a distance of a few millimeters from the surface.

15. The plasma actuator referred to in claim 1 is characterized in that the grounded electrode comprises two or more metallic tubes separated by a gap of about 1 cm through which the ionic wind from the ionizing electrode flows.

16. The plasma actuator referred to in claim 1 is characterized in that the ionizing electrode and the grounding electrode are positioned in a vertical or inclined plane relative to the surface of the solar panel. This configuration facilitates the flow of the generated ionic wind towards the surface of the panel.

17. The solar panel cleaning device according to claim 1 is characterized in that the plasma actuator can be mounted on a mobile vehicle adapted for moving along the surface of a solar panel to clean accumulated dust, or carried by a drone to clean the panel from above.

18. The solar panel cleaning device according to claim 1 is characterized in that it allows the cleaning of any dusty surface, flat or curved, and in all gaseous atmosphere conditions.

19. The plasma actuator according to claim 1 is characterized in that it can also take the form of a curved aerodynamic element, with an opening approximately two centimeters (2 cm) wide at its upper end and approximately one centimeter (1 cm) wide at its lower end. This configuration is designed to generate a horizontal airflow relative to the surface of a solar panel, thereby improving dust removal efficiency.

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