System of photovoltaic solar panels for installation on land for agricultural or livestock use, and method of energy production using this system

Abstract

The system of the photovoltaic solar panels comprises a plurality of photovoltaic solar panels (3) arranged in parallel and spaced-apart rows (2) in the open land (F) so as to enable agricultural or livestock use of the area of the land (F) between said rows (2). Each photovoltaic solar panel (3) is supported by a support structure with the intervention of a tracking device configured to rotate said photovoltaic solar panel (3) during the apparent diurnal movement of the sun. Each photovoltaic solar panel (3) has an array of bifacial photovoltaic solar cells (C) having opposite faces (A, B) exposed respectively on said first surface and said second surface of said photovoltaic solar panel (3) in order to collect both direct and scattered solar radiation. The tracking device is configured such that, except for a temporary phase at solar zenith where a reversal movement executed within a time not exceeding 1 hour is imparted to the photovoltaic solar panel (3), the inclination angle formed between the plane of each photovoltaic solar panel (3) and a vertical plane parallel to the longitudinal direction of said row (2) never exceeds a value of 45° during the entire duration of the apparent diurnal movement of the sun. In this way, during the entire duration of the apparent movement of the sun, the panels are controlled to move between a vertical position and a position relatively close to vertical, whereby the projection of the photovoltaic system onto the ground is always minimized.

Description

Technical Field

[0001] The present invention is a system of photovoltaic solar panels configured to be installed on outdoor land for agricultural and / or livestock use, and is of a type comprising a plurality of photovoltaic solar panels each having a plurality of photovoltaic solar cells, wherein the photovoltaic solar panels are arranged in parallel and spaced-apart rows so as to enable agricultural or livestock use of the area of the land between the rows, each photovoltaic solar panel has a planar structure having a first surface intended mainly to face the sun and a second surface opposite the first surface, and each photovoltaic solar panel is supported by a support structure with the intervention of a tracking device including an actuator and an electronic controller configured to rotate the photovoltaic solar panel during the apparent diurnal movement of the sun. The present invention relates to a system.

Background Art

[0002] Systems of the type of photovoltaic solar panels shown above are known and have been used for some time. In widely used conventional solutions, each row of the photovoltaic solar panels is associated with one or more tracking devices configured to rotate the panels of the entire row during the apparent diurnal movement of the sun, so that the first surface of the photovoltaic solar panel is always maintained facing the sun. In applications where it is desired to coexist the system of photovoltaic solar panels with possible agricultural or livestock management, this solution suggests that when evaluating the space for agricultural or livestock use, it is necessary to take into account that the area corresponding to the projection in the plane of each row of panels is not available when the panels are in a horizontal position. On the other hand, the space between the rows of panels must be sufficient to allow the passage of machinery and equipment for agricultural use and for the maintenance of the photovoltaic system. For a given area where cultivation is to be carried out, there is a limit to the number of rows of panels that can be installed, or conversely, for a given number of rows of panels to be installed, there is a limit to the area where cultivation can be carried out.

[0003] The present invention starts from the desire to find a better compromise between the need to make the production of electrical energy as high as possible through a system of photovoltaic solar panels and at the same time the need to make as large a land area as possible available for agricultural or livestock use.

[0004] A system of a photovoltaic solar panel including a bifacial solar cell installed on an inclined tower integrated with a plurality of reflecting mirrors is known from US2022 / 069767A1.

[0005] [Object of the Invention] The object of the present invention is to solve the above problems in a concise and efficient manner.

[0006] In particular, one object of the present invention is to achieve the best compromise between the need to obtain high energy production for a given extension area of the installation land and the need to maintain a high proportion of available land that can be used for agricultural or livestock use, if desired, by providing a system of photovoltaic solar panels.

[0007] A further object of the present invention is to achieve the above object by extremely simple and efficient means.

[0008] A further object of the present invention is to provide a system of the type indicated above that can be easily adapted to each specific application.

[0009] A further object of the present invention is to reduce the need for maintenance operations, particularly for the regular cleaning of photovoltaic solar panels.

[0010] Yet another object of the present invention is to reduce the potential impact of soil erosion due to atmospheric precipitation.

Summary of the Invention

[0011] In view of achieving one or more of the above objects, the present invention relates to a system of photovoltaic solar panels having the features of claim 1.

[0012] In one embodiment, each photovoltaic solar panel has solar cells having a first side that is relatively more efficient in generating electrical energy and a second side that is relatively less efficient in generating electrical energy. Each photovoltaic solar panel may have all solar cells with their first sides exposed on the first surface of the photovoltaic solar panel. In an alternative example, each photovoltaic solar panel has an alternating distribution of first solar cells with their first sides exposed on the first surface of the photovoltaic solar panel and second solar cells with their first sides exposed on the second surface of the photovoltaic solar panel.

[0013] In a case where each photovoltaic solar panel has a solar cell in which a relatively more efficient first surface is exposed on the first surface of the photovoltaic solar panel, after the photovoltaic solar panel is inverted, the system is configured and programmed such that the surface of the photovoltaic solar panel exposed to the sun is always the surface that was exposed to the sun in the first part of the apparent movement of the sun, whereby the inversion of the panel further involves passing through a position where the photovoltaic solar panel is horizontal.

[0014] In a case where each photovoltaic solar panel has a distribution of solar cells in which its more efficient first surface is alternately exposed on the first surface and the second surface of the photovoltaic solar panel, after the photovoltaic solar panel is inverted, the system is configured and programmed such that the surface of the photovoltaic solar panel exposed to the sun is a surface that was not exposed to the sun in the first part of the apparent movement of the sun, whereby the inversion of the panel does not necessarily involve passing through a position where the photovoltaic solar panel is horizontal.

[0015] Due to the features described above, the system according to the present invention enables the high energy productivity demand and the high productivity demand of areas designated for agricultural or livestock use to be satisfied simultaneously in an optimal manner.

[0016] As can be understood, the solution of the present invention results from the observation that it is possible to abandon the conventional concept of following the apparent movement of the sun by constantly holding the first surface of the photovoltaic solar panel perpendicular to the incident direction of direct solar radiation, due to the possibility of better using diffuse solar radiation.

[0017] According to the present invention, the tilt angle of the photovoltaic solar panel with respect to the vertical never exceeds 45°, preferably never exceeds 35°, and even more preferably never exceeds 20°, that is, it is always in a position significantly closer to the vertical plane than the horizontal plane. By this method, it is possible to significantly increase the production of energy due to the photovoltaic cells arranged on the back surface of the panel that utilize scattered light. In this way, for the same amount of available solar energy, it is possible to obtain slightly lower electrical energy production than that generated by the conventional system that always holds the front surface of the photovoltaic solar panel perpendicular to the incident direction of solar radiation. At the same time, the system according to the present invention enables a dramatic improvement over the conventional system with respect to the area available for agricultural cultivation. This is determined by the fact that the solar panel in a substantially vertical position occupies a significantly smaller space in the plant than the space occupied by the conventional photovoltaic solar panel that remains in a horizontal position for a long time in the middle of the apparent path of the sun.

[0018] Due to this feature, from both the perspectives of the production of electrical energy and the utilization of land for agricultural use, the overall results achievable using the system according to the present invention are significantly superior to those of the conventional system.

[0019] The maintenance of the photovoltaic solar panel that is close to the vertical position for most of the usage time also dramatically reduces the deterioration of the surface quality of the panel caused by atmospheric precipitation, and thus reduces the regular maintenance operations.

[0020] The present invention also relates to a method for generating energy using the system described above.

[0021] According to a further aspect, the present invention relates to a photovoltaic solar panel system comprising a plurality of photovoltaic solar panels, each having a plurality of photovoltaic solar cells and being intended to be arranged in parallel and spaced-apart rows in the open land so as to enable agricultural or livestock use of the area of the land between the rows. Each photovoltaic solar panel has a planar structure and is supported by a support structure, with or without the intervention of a tracking device configured to rotate the photovoltaic solar panel during the apparent diurnal movement of the sun. For each row of photovoltaic solar panels in the system, two photovoltaic solar panels are arranged in a V-shape, which form an angle between them that is never greater than 60°, and the angle has a bisector that is inclined with respect to the vertical plane parallel to the direction of the row by an angle that is never greater than 60°, preferably never greater than 40°. The two photovoltaic solar panels arranged in a V-shape face each other and have surfaces that support respective arrays of bifacial photovoltaic solar cells in a state where the first surface faces towards the inside of the V-shape. Thereby, the photovoltaic solar panels of the solar cells utilize both direct solar radiation mainly on the first surface and scattered solar radiation mainly on the second surface, as well as solar radiation reflected between the surfaces of the two panels. The present invention also relates to a system characterized by this.

[0022] In the prior art, rows of photovoltaic solar panels are spaced at a maximum of four times the orthogonal projection of the panel surface onto the ground. The V-configuration described here enables a reduction of the minimum distance (pitch) required between rows by about 50%.

[0023] A 50% reduction in the orthogonal projection of the panel surface onto the ground increases the light below the axis of rotation.

[0024] In a first example, the tracking device is configured to rotate the two photovoltaic solar panels arranged in a V-shape simultaneously and identically during the apparent diurnal movement of the sun.

[0025] In an alternative example, the tracking device is configured to rotate the two photovoltaic solar panels arranged in a V shape during the apparent diurnal movement of the sun, independently of each other.

[0026] In a preferred embodiment, a flat or convex reflective / scattering surface is arranged at the bottom of the space defined between the two photovoltaic solar panels, which can also be used as a drainage channel capable of carrying rainwater so as to avoid the risk of rain erosion or soil erosion, and therefore, the hydraulic invariability of the installation site is guaranteed.

Brief Description of the Drawings

[0027] Further features and advantages of the present invention will become apparent from the following description with reference to the accompanying drawings, which are provided by way of non-limiting examples only. [Figure 1] Perspective view of a plurality of rows of photovoltaic solar panels constituting a first example of the system according to the present invention, installed on land for agricultural and / or livestock use. [Figure 1A] Side view of a plurality of rows of photovoltaic solar panels constituting a first example of the system according to the present invention, installed on land for agricultural and / or livestock use. [Figure 1B] Side view of a plurality of rows of photovoltaic solar panels constituting a first example of the system according to the present invention, installed on land for agricultural and / or livestock use. [Figure 2] Front view of one of the rows of photovoltaic solar panels shown in FIGS. 1, 1A and 1B. [Figure 3] Figs. 3a1), 3a2), 3a3) and 3a4) show, by way of example, the positions of a conventional type of photovoltaic solar panel at sunrise, just before solar zenith, just after solar zenith and sunset, respectively. Figs. 3b1), 3b2), 3b3) and 3b4) show the corresponding positions in the case of an embodiment of the system according to the present invention. [Figure 4] Figures a), b), c), d), e), and f) of FIG. 4 show the different positions that the photovoltaic solar panel of a preferred embodiment of the present invention progressively assumes during the inversion phase that is carried out, for example, at time intervals of about 30 minutes, substantially at solar zenith. [Figure 5] It is a diagram showing the variation of the tilt angle with respect to the horizontal plane of a photovoltaic solar panel (line I) forming part of the system according to the present invention and a photovoltaic solar panel (line PA) according to conventional techniques. [Figure 6] It is a schematic side view of a photovoltaic solar panel forming part of the system according to the present invention according to two different exemplary embodiments. [Figure 7] It is a schematic side view of a photovoltaic solar panel forming part of the system according to the present invention according to two different exemplary embodiments. [Figure 8] It is a front view of a row of photovoltaic solar panels according to the embodiment of FIG. 6. [Figure 9] It is a table showing the different ratios of the direct component and the scattered component of solar radiation collected by a photovoltaic solar panel for different atmospheric conditions. [Figure 10] It is a side view showing a further example of a system of photovoltaic solar panels installed on land designated for agricultural and / or livestock use according to a further aspect of the present invention. [Figure 11] It is a side view showing a further example of a system of photovoltaic solar panels installed on land designated for agricultural and / or livestock use according to a further aspect of the present invention. [Figure 11A] It is a perspective view of the systems of FIGS. 10 and 11. [Figure 11B] It is a further side view of the systems of FIGS. 10, 11, and 11A. [Figure 11C] It is a further side view of the systems of FIGS. 10, 11, and 11A. [Figure 12]It is a side view of a single row forming part of a system according to a variant of the solution of FIGS. 10 to 11C. [Figure 12A] It is a perspective view of a system according to a variant of FIG. 12. [Figure 12B] It is a further side view of the systems of FIGS. 12 and 12A. [Figure 12C] It is a further side view of the systems of FIGS. 12 and 12A.

Mode for Carrying Out the Invention

[0028] FIGS. 1, 1A, 1B, 2, 3, 4, 5 and 6 show a first embodiment of a system according to the present invention. The system is generally indicated by 1 and comprises a plurality of rows 2 that are parallel to each other and spaced apart, installed on land designated for agricultural and / or livestock use.

[0029] Due to that feature, for reasons that will become apparent later, the system according to the present invention simultaneously satisfies the high productivity demand for electrical energy and the high productivity demand for the area of land designated for agricultural and / or livestock use.

[0030] Each row 2 comprises an arrangement of photovoltaic solar panels 3, each supporting a plurality of double-sided photovoltaic solar cells C arranged in a substantially the same plane and having their opposite faces A and B (see FIGS. 6 and 7) exposed on opposite surfaces of the panel 3.

[0031] The A face of each double-sided solar cell is intended to convert direct solar radiation into electrical energy, while the B face is intended to convert diffused solar radiation.

[0032] Referring to FIGS. 6 and 7, two alternative solutions can be provided. In the first solution shown in FIG. 6, all of its faces A are on the same surface of each photovoltaic solar panel 3 (FIG. 6) intended to mainly collect direct solar radiation, and all of its faces B are on the opposite surface intended to mainly collect diffused solar radiation. In the second solution, also shown in the front views of FIGS. 7 and 8, each photovoltaic solar panel 3 has an alternating distribution of cells with their face A on the first surface of the panel and cells with their face B on the first surface of the panel.

[0033] Referring again to FIGS. 1, 1A, 1B and 2, the attached drawings do not show the structural details of the photovoltaic solar panel 3, and in particular, they do not show the configuration of the frame supporting the panel, which can be of any known type.

[0034] Nor are the structural details of the support structure for each row 2 shown. According to conventional techniques, each row comprises a support structure 4 consisting of a plurality of struts 5 driven into the ground of the installation site shown by F.

[0035] Furthermore, according to techniques known per se, any known type of tracking device can be interposed between the frame and the support structure 4, each supporting an array of photovoltaic solar panels 3, to impart a progressive rotational movement to the photovoltaic solar panels 3 of each row 2 during the apparent diurnal movement of the sun. The structural details of the tracking devices are not shown here, because they can be obtained in any known way and because the understanding of the drawings is made more immediate and easier by deleting these details from the drawings. According to the prior art, each tracking device includes an actuator, for example, a servo-controlled electric actuator 50 (shown schematically in FIGS. 2 and 8) controlled by an electronic controller E (FIGS. 2 and 8) according to a predetermined program. Furthermore, according to the prior art, the system is equipped with an electronic controller configured to rotate the photovoltaic solar panels according to any predetermined program during the apparent diurnal movement of the sun.

[0036] Figures 3 to 5 show the main differences between the system according to the invention in the embodiments described herein and a conventional system that always maintains one surface of a photovoltaic solar panel perpendicular to the incident direction of solar radiation.

[0037] In particular, FIG. 5 shows the variation of the angle formed between the plane and the horizontal plane of a photovoltaic solar panel as a function of time in the case of the embodiment described herein (line I) and in the case of a conventional system (PA line). In FIG. 5, on the horizontal axis, the time point “0” substantially corresponds to the solar zenith, and the numbers indicate the time before and after the time point “0”. However, it must be considered that the time of day corresponding to a particular position of the photovoltaic solar panel varies widely for each particular application according to the geographical location and according to the date of the year. Therefore, in the diagram of FIG. 5, the numbers on the horizontal axis are merely illustrative.

[0038] Referring to the example of FIG. 5, in the conventional system (line PA in FIG. 5), at sunrise (e.g., around 6 am), the plane of the photovoltaic solar panel of the conventional system forms an angle of 60° with respect to the horizontal plane, i.e., an angle of 30° with respect to the vertical (see also a1 in FIG. 3). Further, in the case of the conventional system, during the morning, since the plane of the photovoltaic solar panel follows the solar orbit, the angle formed with respect to the horizontal plane significantly decreases. For example, around mid-morning, the angle from the horizontal plane is 30°, which means that the angle from the vertical is 60°. At the end of the morning, the photovoltaic solar panel is gradually approaching the horizontal position, where it remains substantially the same for a long time, e.g., from 1 hour before solar zenith to 1 hour after solar zenith (see also a2 and a3 in FIG. 3).

[0039] Referring again to FIG. 5, in the case of the conventional system, the rotation of the photovoltaic solar panel continues gradually in the afternoon while reproducing in reverse what occurred in the morning, whereby the angle formed with respect to the horizontal plane begins to increase again from a value of 0 to a maximum value of 60° (see also a4 in FIG. 3).

[0040] As shown in FIG. 5, the system according to the present invention maintains the photovoltaic solar panel at an angle with respect to the horizontal plane that varies gradually between 90° and 70° during the entire apparent diurnal motion of the sun in the example shown, which corresponds to a variation in the angle formed with respect to the vertical between 0° and 20°, provided that this maintenance excludes the time interval around solar zenith, for example a time interval lasting about 30 minutes, during which each photovoltaic solar panel undergoes an inversion movement as will be explained in more detail below.

[0041] In the example of the present invention shown in FIGS. 3 and 5, in the early morning, the photovoltaic solar panel is vertical or substantially vertical. During the morning, the angle formed with respect to the horizontal plane decreases gradually and, in this example, linearly between a value of 90° and a value of 70°, which means that near solar zenith, the maximum inclination angle with respect to the vertical reached by the photovoltaic solar panel (line I in FIG. 5) is about 20°.

[0042] Referring to the preferred embodiment shown here, during a relatively short period, for example 30 minutes, each photovoltaic solar panel is inverted at the start and end of the time interval such that the photovoltaic solar panel inclines on opposite sides of the vertical plane. An example of such an inversion movement is shown in FIG. 4, where it can be seen that during the time interval required for the inversion movement, the photovoltaic solar panel moves from a 20° inclination (a in FIG. 4) with respect to the vertical plane passing through the rotation axis of the panel to a 20° inclination (f in FIG. 4) on the other side of the vertical plane. FIGS. 4b, 4c, 4d, and 4e show various intermediate positions between the start and end positions of the inversion.

[0043] In this example, throughout the morning and throughout the afternoon, the photovoltaic solar panel remains in the substantially vertical position, i.e., it never exceeds an inclination angle of 20° with respect to the vertical, but rather approaches the fully vertical position at the start and end of the sun's diurnal motion. The above maximum inclination angle is exceeded only during the above time interval, during which the inversion movement takes place.

[0044] The example of FIG. 4 refers to the case of the embodiment of FIG. 6, and all the cells of the photovoltaic solar panel have their first surface A exposed on the first surface of the panel. Therefore, the inversion movement must, for example, make the surface supporting the cell's surface A, which faced the sun during the morning, always face the sun during the afternoon as well, which suggests that in the inversion movement, the photovoltaic solar panel must pass through the horizontal position (see c in FIG. 4 and d in FIG. 4). However, embodiments of FIGS. 7 and 8 are also provided where both the surface A of some cells and the surface B of other cells are exposed on each surface of the photovoltaic solar panel 3. Therefore, in the case of this embodiment, it can be provided that the inversion movement is performed such that the surface that does not face the sun in the afternoon is the surface that faced the sun in the morning. In this case, the inversion movement can be performed not by passing through the horizontal position, but only through a rotation of -20° to +20° with respect to the vertical plane. This feature can be somewhat important, as it eliminates the more restricted space between rows that is available for the passage of agricultural machinery and / or machinery for the maintenance of the photovoltaic system, even for very short time intervals.

[0045] As already discussed above, in fact, obtaining a system that enables a significant reduction in the space occupied in the plane by the system of photovoltaic solar panels so as to increase the space available for agricultural cultivation is an essential element of the present invention.

[0046] Referring to FIG. 1B, the inclination angle of each photovoltaic solar panel 3 with respect to the vertical plane never exceeds that shown in FIG. 1B, except for the time interval required for the panel's inversion movement. As a result, there is a space with a width D larger than that available in a conventional system having columns 2 with struts 5 arranged at the same distance shown in FIG. 1 between each column and the other columns.

[0047] Of course, by abandoning the maintenance of the main surface of the photovoltaic solar panel always perpendicular to the incident direction of solar radiation, the amount of energy obtained from direct solar radiation decreases. However, the overall result is that the substantially vertical orientation of the photovoltaic solar panel enables higher efficiency in the utilization of diffused solar radiation through the surface of the photovoltaic cells on the surface not exposed to the sun, without substantial reduction in energy production.

[0048] FIG. 9 is a table showing that the ratio of direct solar radiation utilized by the surface of the photovoltaic solar panel facing the sun to diffused solar radiation utilized by the surface of the photovoltaic solar panel not facing the sun varies significantly with changes in weather conditions. The table in FIG. 9 also shows the variation of power in watts per square meter as the atmospheric conditions change. When the available energy in sufficient sunlight is 1000 W / m2, in progressively deteriorating atmospheric conditions, this energy gradually decreases to a maximum of 50 W / m2 when the sky is covered with clouds. At the same time, the ratio between direct solar radiation and diffused solar radiation ranges from 90% - 10% to 0% - 100%.

[0049] The above further illustrates how important the incidence of diffused solar radiation can be, especially in geographical areas where the atmospheric conditions are likely to change frequently. This also demonstrates again the advantages of the concept underlying the present invention, which lies in always maintaining the photovoltaic solar panel in a substantially vertical position. In this substantially vertical position, the inclination angle of the photovoltaic solar panel with respect to the vertical plane parallel to the direction of the columns does not exceed a predetermined value.

[0050] In the example described above, this predetermined maximum value of the inclination angle with respect to the vertical is 20°. However, it is included within the present invention to provide that the angle does not exceed a value of 45°, preferably that it does not exceed an angle of 35°, and even more preferably that it does not exceed an angle of 20°.

[0051] In a practical application of the solution in FIG. 1, for a given geographical area and for each date of the year, a simulation campaign was carried out via software to determine the results obtained in terms of electrical energy generated for different values of the inclination angle of panel 3 within the range of variation of this angle that forms the object of the present invention. Based on this simulation, it was possible to define an active tracking algorithm by which the panel positions itself at the best incident angle for energy production within the selected range of angles at any time of the day that is useful for production.

[0052] FIGS. 10, 11, 11A, 11B and 11C show a system of photovoltaic solar panels installed on land designated for agricultural and / or livestock use, according to a further aspect of the present invention.

[0053] In these figures, parts common to those of FIGS. 1 to 9 are indicated by the same reference numerals.

[0054] In the case of the systems of FIGS. 10, 11, 11A, 11B and 11C, for each row 2 of photovoltaic solar panels, two series of photovoltaic solar panels 3A, 3B are provided, each composed of a plurality of bifacial photovoltaic solar cells and arranged in two planes forming a V-shape, which have surfaces facing each other, whereby the photovoltaic solar cells utilize direct solar radiation mainly on the inner surface of the V-shape, which is the main surface of the cell, and scattered solar radiation mainly on the outer surface, and solar radiation received by one or more reflections between the said surfaces of the two panels 3A, 3B.

[0055] The two panels 3A, 3B can be rotated about the horizontal axis 6 by any known type of tracking device (not shown) controlled by an electronic controller.

[0056] In this solution, a single tracking device is configured to cause the simultaneous rotation of the two panels 3A, 3B about the axis 6, so that these panels always remain in the same relative position.

[0057] According to the present invention, the panels 3A, 3B form an angle α between them, which never exceeds 60°. Further, the angle bisector 7 defined between the two photovoltaic solar panels 3A, 3B forms an angle β with respect to the vertical plane, which never exceeds a value of 60°, and preferably never exceeds a value of 45°.

[0058] The tracking device is configured to rotate the set of two panels 3A, 3B during the apparent diurnal motion of the sun, whereby the angle bisector 7 is oriented vertically in the middle along the apparent motion of the sun (Fig. 10b), while on the other hand, it is inclined on opposite planes (by an angle not exceeding 60° with respect to the vertical) at the start and end of the apparent diurnal motion of the sun (Fig. 10a and Fig. 10c). During the morning and during the afternoon, the set of two panels is caused to rotate gradually from one position to another by the tracking device according to a predetermined program in which the electronic controller is configured.

[0059] Fig. 10 shows an example where the angle α is approximately equal to 60°, while the angle β at the start and end of the solar orbit is approximately equal to 20°.

[0060] Fig. 11 is substantially the same as Fig. 10, but shows, by dashed lines, the case where the two panels form an angle α' smaller than α between them.

[0061] Figures 11A and 11B show a perspective view and a further side view of the system of FIGS. 10 and 11. These figures also show in this embodiment that the system of the present invention is configured for installation on a plot of land F designated for agricultural and / or livestock use, aiming to make both productions, namely the production of electrical energy and agricultural and / or livestock production, as efficient as possible.

[0062] Figure 11C shows that when the direction of the incident solar radiation is indicated by R in the figure at the start and end of the solar orbit, a pitch D between columns is selected that is sufficient to ensure that the panels 3B of each column do not shield the panels 3A of the adjacent column.

[0063] Figures 12, 12A, 12B and 12C refer to a variant of the solution of FIGS. 10 and 11, in which two series of panels 3A, 3B are controlled by respective tracking devices so as to rotate around respective axes 6A, 6B, and these axes either coincide with each other or, as in the case shown, are parallel and slightly spaced from each other. Thus, in this solution, the two series of panels 3A, 3B can be rotated synchronously, with the same rotation and independently of each other, as in the case of the solution of FIGS. 10 and 11, whereby the angle α formed between the two series of panels 3A, 3B can vary over time, as shown in a), b) and c) of FIG. 12B.

[0064] Figure 12C shows that by taking advantage of this possibility, when the direction of the incident sunlight is indicated by R, the angle α formed between the two series of panels 3A, 3B can be reduced at the start and end of the solar orbit, and thus the length of the pitch D, which is prevented from the panels 3B of each row shielding the panels 3A of the adjacent row, is proportionally smaller than in the case of Figure 11C. Preferably, the reflecting / scattering surface 9 (Figure 12) is provided at the bottom of the space defined between two photovoltaic solar panels arranged in a V shape, which can be a flat surface or a convex surface (as in the example shown in Figure 12), carry rainwater to a dedicated drainage channel, and can also be configured to operate as a drainage channel so as to reduce the risk of soil erosion due to precipitation.

[0065] Of course, without prejudice to the principles of the invention, the details of the structure and embodiments can vary widely with respect to those merely illustrated and described by way of example, without departing from the scope of the invention as defined by the appended claims.

Claims

1. A system of photovoltaic solar panels configured to be installed on outdoor land for agricultural and / or livestock use, comprising a plurality of photovoltaic solar panels, each having a plurality of photovoltaic solar cells, wherein the photovoltaic solar panels are arranged in parallel and spaced-apart rows so as to enable agricultural or livestock use of the area of the land between the rows, each photovoltaic solar panel having a planar structure with a first surface and a second surface opposite the first surface, each photovoltaic solar panel being supported by a support structure with the intervention of a tracking device including an actuator and an electronic controller configured to rotate the photovoltaic solar panel during the apparent diurnal motion of the sun, each photovoltaic solar panel being in the same plane with each other and having an array of flat double-sided photovoltaic solar cells arranged in the plane of each respective photovoltaic solar panel, the flat double-sided photovoltaic solar cells having opposite surfaces exposed respectively on the first surface and the second surface of the photovoltaic solar panel, whereby the first surface of the photovoltaic solar panel can mainly collect direct solar radiation, and the second surface of the photovoltaic solar panel can mainly collect scattered solar radiation, the electronic controller of the tracking device being configured such that, except for a temporary phase at solar zenith where a reversal motion executed within a time not exceeding 1 hour is imparted to the photovoltaic solar panel, the inclination angle formed between the plane of each photovoltaic solar panel and a vertical plane parallel to the longitudinal direction of the row never exceeds a value of 45°, preferably never exceeds a value of 35°, and even more preferably never exceeds a value of 20° during the entire duration of the apparent diurnal motion of the sun, the electronic controller of the tracking device, wherein the inclination angle of the photovoltaic solar panel varies gradually between an angle close to 0° at the start and end of the apparent diurnal motion of the sun, and an angle between 5° and 40°, preferably between 15° and 35°, and even more preferably equal to about 20° at substantially solar zenith, Substantially near the solar zenith, the photovoltaic solar panel is reversed within a time interval not exceeding one hour, whereby, at the start and end of the time interval, the photovoltaic solar panel is inclined on opposite surfaces with respect to a vertical reference plane parallel to the longitudinal direction of the row and is configured and programmed system.

2. The system according to claim 1, wherein each photovoltaic solar panel has solar cells having a first surface that is relatively more efficient in generating electrical energy and a second surface that is relatively less efficient in generating electrical energy.

3. The system according to claim 2, wherein each photovoltaic solar panel has solar cells all of whose first surfaces are exposed on the first surface of the photovoltaic solar panel.

4. The system according to claim 2, wherein each photovoltaic solar panel has an alternating distribution of first solar cells whose first surfaces are exposed on the first surface of the photovoltaic solar panel and second solar cells whose first surfaces are exposed on the second surface of the photovoltaic solar panel.

5. Each photovoltaic solar panel has solar cells having a first surface that is relatively more efficient in generating electrical energy and a second surface that is relatively less efficient in generating electrical energy, all of the solar cells of each photovoltaic solar panel having their first surfaces exposed on the first surface of the photovoltaic solar panel, the tracking device being configured and programmed such that, after the photovoltaic solar panel is reversed, the surface of the photovoltaic solar panel exposed to the sun is always the surface that was exposed to the sun in the first part of the apparent movement of the sun, whereby the reversal of the photovoltaic solar panel involves passing through a position where the photovoltaic solar panel is horizontal, the system according to any one of claims 1 to 4.

6. Each photovoltaic solar panel has solar cells having a first surface that is relatively more efficient in generating electrical energy and a second surface that is relatively less efficient in generating electrical energy, Each photovoltaic solar panel has an alternating distribution of a first solar cell whose first face is exposed on the first surface of the photovoltaic solar panel and a second solar cell whose first face is exposed on the second surface of the photovoltaic solar panel. The tracking device is configured and programmed such that after the photovoltaic solar panel is inverted, the surface of the photovoltaic solar panel exposed to the sun is the surface that was not exposed to the sun in the first part of the apparent movement of the sun, whereby the inversion of the photovoltaic solar panel does not involve passing through a position where the photovoltaic solar panel is horizontal. The system according to any one of claims 1 to 4.

7. A system of photovoltaic solar panels, each having a plurality of photovoltaic solar cells and being intended to be arranged in parallel and spaced-apart rows in the open land so as to enable agricultural or livestock use of the areas of the land between the rows. Each photovoltaic solar panel has a planar structure and is supported by a support structure, with or without the intervention of a tracking device configured to rotate the photovoltaic solar panel during the apparent diurnal movement of the sun. For each row of photovoltaic solar panels, two series of photovoltaic solar panels are provided, arranged in two planes forming a V-shape, which form an angle between them that is never greater than 60°, and the angle has a bisector that is inclined with respect to a vertical plane parallel to the direction of the row by an angle that is never greater than 60°, preferably never greater than 40°. The two photovoltaic solar panels arranged in a V-shape face each other and have surfaces that support respective arrays of bifacial photovoltaic solar cells, whereby the photovoltaic solar cells utilize both direct and diffuse solar radiation and solar radiation reflected between the surfaces of the two panels. The system.

8. The system according to claim 7, comprising a tracking device configured to rotate the two photovoltaic solar panels arranged in a V-shape simultaneously and identically during the apparent diurnal movement of the sun.

9. A system according to claim 7, comprising a tracking device configured to rotate the two photovoltaic solar panels, which are arranged in a V-shape and are independent of each other, around two axes that coincide with or are parallel to each other and are spaced apart, during the apparent diurnal movement of the sun.

10. A system according to any one of claims 7 to 9, wherein a flat or convex reflective / scattering surface is provided at the bottom of the space defined between the two photovoltaic solar panels arranged in a V-shape, which is preferably configured to operate as a drainage channel.

11. A system according to any one of claims 7 to 9, wherein the rows are arranged at a pitch sufficient to avoid the photovoltaic solar panels of each row shading adjacent rows at the start and end of the apparent movement of the sun.

12. A method for collecting solar energy, comprising: providing a system of photovoltaic solar panels, each comprising a plurality of photovoltaic solar panels having a plurality of photovoltaic solar cells; the photovoltaic solar panels are arranged in parallel and spaced rows in the field land to enable agricultural or livestock use of the areas of the land between the rows; each photovoltaic solar panel has a planar structure having a first surface and a second surface opposite the first surface; each photovoltaic solar panel is supported by a support structure with the intervention of a tracking device including an actuator and an electronic controller configured to rotate the photovoltaic solar panel during the apparent diurnal movement of the sun; the method further comprises: each photovoltaic solar panel is in the same plane as each other and has an array of flat double-sided photovoltaic solar cells arranged in the plane of each respective photovoltaic solar panel; the flat double-sided photovoltaic solar cells have opposite surfaces exposed on the first surface and the second surface of the photovoltaic solar panel, respectively, whereby the first surface of the photovoltaic solar panel can mainly collect direct solar radiation, and the second surface of the photovoltaic solar panel can mainly collect scattered solar radiation. The tracking device is controlled such that, except for a temporary phase at solar zenith where a reversing motion executed within a time not exceeding 1 hour is imparted to the photovoltaic solar panel, the inclination angle formed between the plane of each photovoltaic solar panel and a vertical plane parallel to the longitudinal direction of the row does not exceed a value of 45° throughout the duration of the apparent diurnal motion of the sun, preferably does not exceed a value of 35°, and even more preferably does not exceed a value of 20° at any time, The tracking device is, in particular, such that the inclination angle of the photovoltaic solar panel varies gradually between an angle close to 0° at the start and end of the apparent diurnal motion of the sun, and an angle between 5° and 40° at solar zenith, preferably between 15° and 35°, and even more preferably equal to approximately 20°, near solar zenith, the photovoltaic solar panel is reversed within a time interval not exceeding 1 hour, whereby at the start and end of the time interval, the photovoltaic solar panel is inclined on opposite sides with respect to a vertical reference plane parallel to the longitudinal direction of the row is controlled method. **Claim 13** During the apparent motion of the sun, the inclination angle of the photovoltaic solar panel varies within the indicated range of variation according to a law determined based on a simulation via software that calculates the electrical energy generated for a given geographical area for each time of each date of the year and for different values of this inclination angle within the indicated range of variation. The method according to claim 12.

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