WO2008096193A1

WO2008096193A1 - System for producing energy with solar panels

Info

Publication number: WO2008096193A1
Application number: PCT/IB2007/000508
Authority: WO
Inventors: Claudio Londero
Original assignee: Claudio Londero
Priority date: 2007-02-05
Filing date: 2007-03-02
Publication date: 2008-08-14
Also published as: ITMO20070038A1

Abstract

A system for producing energy through solar panels (3) with at least one energy-producing unit (1) comprising at least one solar panel (3) , the system comprises first rotating means (5, 6, 7, 8, 9, 10, 11) for rotating said at least one panel with respect to an axis parallel to a surface of the panel and second rotating means (18, M) for rotating said at least one energy-producing unit (1) with respect to a substantially horizontal axis, in such a way as to orientate said at least one panel (3) in function of the position of the sun in the course of the day and the height of the sun on the horizon.

Description

System for producing energy with solar panels .

The present invention relates to a system for producing energy through solar panels, such as photovoltaic panels, or thermohydraulic panels, in particular a system that may be installed on the horizontal or tilted roof of a building, or also on the ground.

From the prior art systems are known for producing energy by means of solar panels installed on roofs of buildings, in which the panels are installed in a fixed position on the roof of a building.

This entails inappropriate utilisation of the panels, inasmuch as the solar energy received by the panels varies with the variation of the position of the sun with respect to the panels and the height of the sun on the horizon, being maximum only when the rays of sun reach the panels in a direction substantially perpendicular to the surface thereof.

However, this condition occurs only at certain periods of the year and for a short period over the course of the respective days. For all the rest of the day and periods of the year, the rays of the sun reach the surface of the panels with an inclination that is less, even much less, than 90°, which involves a significant reduction, even by up to 50%, of the solar energy received by the panels with respect to the optimal condition of solar rays with an angle of incidence of 90°.

The object of the present invention is to provide a system for producing energy through solar panels that is able to operate as far as possible in conditions near to optimum conditions, i.e. with an angle of incidence of the solar rays as near as possible to 90° for most of the day and over the year.

According to the present invention there is provided a system for producing energy through solar panels with at least an energy-producing unit comprising at least one solar panel, characterised in that it comprises first rotating means for rotating said at least a panel with respect to an axis parallel to a surface of the panel and second rotating means for rotating said at least a unit with respect to a substantially horizontal axis, in such a way as to orientate said at least a panel in function of the position of the sun in the course of the day and the height of the sun on the horizon.

The invention will be disclosed below with reference to the attached drawings, in which: Figure 1 is a plan view of a group of photovoltaic panels of a system according to the invention;

Figure 2 is a schematic section view of a roof of a building with groups of panels installed according to the invention; Figure 3 is a side view of the group of panels in Figure 1, showing a lifting device of the group of panels;

Figure 4 is a wiring diagram of groups of panels according to the invention;

Figure 5 is a diagram that illustrates the positioning of panels according to the invention according to the height of the sun on the horizon;

Figure β is a schematic section view of a roof of a building with groups of solar panels installed, according to a version of the invention; Figure 7 is a general diagram of a system according to the invention.

The system according to the invention comprises one or more energy producing units 1, which may be installed on the roof of a building, or also on the ground. An energy producing unit 1 according to the invention is illustrated in Figure 1.

The energy producing unit 1 comprises a frame 2 with a substantially rectangular shape, on which there is supported at least a panel 3, consisting of photovoltaic cells, or of a thermohydraulic panel. In the embodiment illustrated, the energy producing unit comprises three photovoltaic panels 3. The longer sides of the frame 2 are reinforced by stiffening plates 4, with an "L"-shaped section, provided with a corrugated surface to increase the stiffness thereof. Each panel 3 is rotatingly connected to the longer sides of the frame 2 through a first pin 5 and a second pin 6 located on opposite sides of the panel 3. The axes of the first pin 5 and of the second pins 6 are aligned with one another. The first pin 5 and the second pin 6 of each panel 3 are rotatingly supported in respective bushes 7 fixed to the longer sides of the frame 2.

An end of each first pin 5, facing the outside of the frame 2, is fixed to the centre of a respective disc 8. The discs 8 associated with the first pins 5 are coupled, in a rotatingly coupled manner, in a position that is eccentric with respect to the centre thereof, with a connecting rod 9, driven by a linear actuator 10 fixed to the frame 2; the linear actuator 10 drives the connecting rod 9 by means of a sleeve 11, articulated at an end on the connecting rod 9 and coupled at a second end with the shaft 12 of the linear actuator 10.

By driving the linear actuator 10, the connecting rod 9 can be moved in a direction parallel to the longitudinal axis thereof, rotating the discs 8 and consequently the first pin 5 coupled with the discs 8. Rotating the discs 8 thus causes a corresponding rotation of the panels 3 around the axes of the first pins 5 and of the second pins 6 to orientate the panels 3 according to the position of the sun in the sky in the course of a day, in such a way as to optimise the position of the surface of the panels 3 with respect to the rays of the sun so that the angle of incidence of the rays on the surface of the panels 3 is the maximum possible angle, i.e. in order to maximise the solar energy received by the panels 3 per surface unit. The end of each second pin 6 of each panel 3 facing the outside of the frame 2 is fixed to the centre of a respective further disc 13. The further discs 13 are connected together in pairs by- further connecting rods 14, rotatingly connected at the respective ends to respective coupling pins 15 fixed to the respective disc 13 in an eccentric position with respect to the centre of the disc 13.

Further adjacent connecting rods 14 are connected to the same disc 13 in positions diametrically opposite the centre of the disc 13. Each further connecting rod 14 is connected to the respective coupling pins 15 by a first threaded connecting element 16 at a first end of the further connecting rod 14 and a second threaded connecting element lβa at a second end of the further connecting rod 14 opposite said first end. The threaded elements 16, 16a are screwed into corresponding threaded seats obtained in said first and in said second end of the further connecting rod 14. The threads of the threaded elements 16 and 16a have opposite directions. This enables, during the rotation movement of the panels 3, plays to be recovered that may arise between the connecting rods 14 and the discs 13, thus eliminating or at least significantly reducing vibrations that said plays could cause.

The distance D between two adjacent panels 3 is preferably at least equal to half the width L of the panel in order to prevent, in particular when the sun is low on the horizon, the panels 3 mutually screening themselves, thus significantly reducing the surface that the rays of the sun hit. The energy producing units 1 constitute modular elements of the system that can be assembled separately before being installed on the roof of a building, which enables the installation of the system to be significantly simplified and accelerated. In Figure 2 there is illustrated the mounting of the energy producing units 1 on the roof T of a building, shown in section in a schematic manner. The frame 2 of each energy producing unit 1 (Figure 2) is articulated, at two vertices that are adjacent to one another, on respective supporting elements 17 associated with the roof T, in such a way as to be able to rotate with respect to said supporting elements 17, around an axis A substantially parallel to the longer sides of the frame 2. The frame 2 is further connected to a pair of lifting elements 18, only one of which is visible in Figure 2, which are used to modify the angle of inclination of the frame 2 and therefore of the panels 3, with respect to the roof T, rotating the frame 2 with respect to the supporting elements 17, in such a way as to optimise the position of the panels 3 according to the height of the sun on the horizon in the various seasons of the year to maximise the solar energy hitting the panels 3 per surface unit. The lifting elements 18 are supported by further supporting elements 19 associated with the roof T.

Each lifting element 18 (Figure 3) consists of an articulated parallelogram comprising four connecting elements 20, 20a, 20b, 20c, for example ^λΛU"-shaped plates, on which the ends of four rods 21, 21a, 21b, 21c are hinged, for example with a box section. A first plate of said four plates, for example plate 20, is fixed to a respective further supporting element 19, whilst a second plate, for example plate 20a, opposite plate 21, is fixed to the frame 2 of an energy producing unit 1. Between the third and the fourth plate 20b and 20c there is arranged a linear actuator 22 comprising a worm 23, rotated by a motor M fixed, for example, to the fourth plate 2Od, by means of a dual-effect thrust bearing 24, and a hollow cylindrical element 25 that is fixed at a first end to the plate 20c and which terminates, at a second end opposite said first end, with a nutscrew sleeve 26 that engages with the worm 23. The worm can be driven, albeit less advantageously, by a crank rather than by the motor M. The end of the feed screw 23 that is coupled with the sleeve 26 is provided with a stop element that prevents the feed screw 23 from leaving the sleeve 26 and constitutes a first end stroke element that determines the maximum elongation of the linear actuator 18, i.e. the maximum distance between the plates 20b and 20c, to which the minimum angle of inclination between the frame 2 and the roof T of the building corresponds. The sleeve 26 constitutes in itself a second end stroke element that, by abutting against the plate 20b, determines the minimum elongation of the linear actuator 18, i.e. the minimum distance between the plates 20b and 20c, to which corresponds the maximum angle of inclination of the frame 2 with respect to the roof T of the building. By driving the linear actuator 22 the configuration of the articulated parallelogram 18 is modified in such a way that the vertex of the articulated parallelogram 18 connected to the frame 2 constituted by the second plate 20a can move towards or away from the opposite vertex consisting of the first plate 20, rotating the frame 2 with respect to the supporting elements 17 and thus modifying the angular position of the frame 2 with respect to the roof T of the building. By adjusting the inclination of the frame 2 with respect to the roof T of the building and adjusting the angular position of the panels 3 in the frames 2 it is possible to optimise the position of the surface of the panels 3 with respect to the incident rays of the sun as the position of the sun changes over the course of the day and as the height of the sun on the horizon changes over the course of the seasons so that the angle of incidence of the rays of the sun on the surface of the panels 3 is maximum whatever the position of the sun on the horizon. In Figure 2 there is illustrated, by way of example, the position of a first and of a second frame 2 on the roof T of a building, in two different situations with respect to various heights of the sun on the horizon.

It should be noted that the fact that the rods 21, 21a, 21b, 21c are not hinged together but on the plates 20, 20a, 20b, 20c, increases the degrees of freedom of the articulated parallelogram 18, thus preventing flexure stress being able to develop during the movements of the articulated parallelogram 18 for rising and lowering the frame 2, which flexure stress could easily compromise the operation of the linear actuator 22.

With one of the second pins 6 there is associated a first rotation sensor Sl, for example a potentiometer sensor, which detects the angle of rotation of the panels 3 around the pins 5, 6 with respect to a reference position. With the rotation axis A of the frame 2 there is associated a second rotation sensor S2, which is for example also a potentiometer sensor, which detects the rotation angle of the frame 2, with respect to a reference position. In Figure 4 there is shown a wiring diagram of an energy producing system according to the invention, consisting of four energy producing units, indicated by the numbers Ia, Ib, Ic, Id, each of which comprises three photovoltaic panels 3 serially connected together. The energy producing units Ia, Ib, Ic, Id are connected serially in pairs, for example the energy producing units Ia, Ib and the energy producing units Ic, Id are connected serially in pairs. Each pair of energy producing units Ia, Ib and Ic, Id is connected to a respective DC/AC converter 27a, 27b by means of respective electric lines 28a, 28b each of which is provided with an overvoltage limiting device 29a, 29b, that grounds the respective line 28a, 28b if the voltage on the line exceeds a preset value. On the lines 28a and 28b there are further provided first respective circuit breakers 33, 33a, to enable said lines to be disconnected from the panels 3, where necessary, and second respective circuit breakers 34, 34a, to enable the first DC/AC converters 27a, 27b to be disconnected from the lines 28a, 28b, where necessary, or in the event of an emergency. On each of the lines 28a and 28b there is further provided a respective current sensor 35 and a respective voltage sensor 36, preferably of digital type. The current sensors are used for fine adjustment of the position of the panels 3. The positions of the frames 2 and of the panels 3 are adjusted approximately on the basis of the known position of the sun at the various hours of the day, the orientation of the frames 2 and of the panels 3 being adjusted at preset intervals .

The positions of the panels 3 are fine-adjusted on the basis of the value of the current detected by the sensors 35 in such a way as to orientate the panels 3 in a position in which the maximum current is detected by the sensors, which corresponds to the maximum angle of incidence of the rays of the sun that is possible on the surface of the panels 3. The two DC/AC converters 27a, 27b are connected parallel to a further electric line 30 that is connectable to the electrical system 31 of the building, or to the mains distribution network. On the line 30 there is provided a further overvoltage limiting device 32, having a similar function to that of the previously cited devices 29a, 29b. The two DC/AC converters 27a, 27b are further provided with a respective data bus 37 through which data relating to the operation of the converters to monitor the operation thereof and detect irregular situations can be transmitted to a data processing system, for example a personal computer. In Figure 5 there is schematically illustrated the positioning of an energy producing unit 1 as the seasons change, i.e. as the maximum height of the sun on the horizon during the day changes .

A dot and dash line shows the pitch of the roof T of a building, which forms an angle b with a horizontal plane. The position assumed by an energy producing unit and by a respective articulated parallelogram lifting element in the summer season is shown by a continuous line whilst the position taken in the winter season is shown by a broken line.

In the summer position, the energy producing unit is shown by the reference number Ia and the corresponding articulated parallelogram lifting element by the reference number 18a, whilst in the winter position the energy producing unit is indicated by the reference number Ib and the lifting element is indicated by the reference number 18b. As can be seen by the Figure, the angle that the energy producing unit forms with the pitch T of the roof varies from a minimum value a' in the summer season, when the angle of incidence of the rays of the sun with respect to the ground is maximum, to a maximum value a' ' in the winter season, when the angle of incidence of the rays of the sun with respect to the ground is minimum, in such a way as to obtain in each season the maximum angle of incidence of the rays of the sun on the photovoltaic panels. It should be noted that the energy producing unit can be positioned in such a way as to form with the pitch of the roof T an angle less than a' , until it is arranged substantially parallel to the pitch of the roof T, with the object of taking the energy producing units 1 to a secure position in the event of unfavourable climatic conditions with a strong wind.

In Figure 6 there is illustrated a version of the system according to the invention.

In this version, in the roof T of the building there are obtained seats 38 inside which the energy producing units can be retracted flush, in particular to take them to a secure position in the event of unfavourable climatic conditions with a strong wind. This enables the energy producing units that could be damaged to be protected from the effects of the wind with maximum efficacy. In Figure Ia the operating position of the energy producing units is indicated by the numeral 1, whilst the secure position is indicated by the numeral 1' .

In Figure 7 there is illustrated an operating diagram of a system according to the invention, referring to a system with four energy producing units.

Each energy producing unit is associated with an electronic card 39 connected to a data processing system 40, for example a personal computer, that manages the various functions of the system. The personal computer 40 can be connected, by means of a connection 52 to a data recording unit 53 for recording data on a removable support, for example a CD, or a DVD. Further, the personal computer 40 can be connected to a line 54 for remote transmission of data, to enable the system to be managed from a remote station.

The current sensors 35 and the voltage sensors 36 associated with the DC/AC converters 27a are 27b are connected to the electronic cards 39, by means of a junction box 43 and a terminal board 42. In addition to the electronic cards 39 are connected:

- the rotation sensors Sl and S2, which detect the rotation angle of the energy producing units 1 and of the panels 3 of each energy producing unit 1; - the motors 10 that control rotation of the panels 3;

- the motors M that control the linear actuators 22;

- sensors 44 that detect the rotation angle of the shaft of the linear actuator 10 and of the motor M with respect to a reference angular position; - a pyranometer 45, that detects the intensity of the solar radiation, in such a way that it is possible to disable the system when the intensity of the solar radiation falls below a preset minimum value;

- an anemostat 46 and an anemometer 47 that are used to measure, respectively, the direction and the intensity of the wind, with the object of placing the energy producing units 1 in a secure position, if the intensity and the direction of the wind may jeopardise the stability of the energy producing units 1;

- temperature sensors 48; - limit switch sensors 49, to control stopping of the motor M and of the linear actuator 10, when the movements of the energy producing units 1 and/or the panels 3 reach preset limit positions; a motor 50 that supplies a lubrication circuit for lubricating the moving mechanical parts;

- a wind dynamo 51 that acts as an emergency generator for operating the system, in particular for driving motors 10 and M, if the power to the motors fails and, due to the wind, it is necessary to place the energy producing units 1 and the panels 3 in a secure position by driving the aforesaid motors; between the wind dynamo and the motors 10 and M there is interposed an AC/DC converter 52, to drive said motors, which, preferably, are 12V direct current motors . The wind dynamo can be replaced by an emergency energy source, for example by a so-called continuity unit, for the emergency operation of the energy producing units 1 and of the panels 3. The system according to the invention is further provided with at least a camera 38, connected to the personal computer 40, for remote visual surveillance of the system. In the practical embodiment, the materials, dimensions and constructional details may be different from those indicated but be technically equivalent thereto without thereby falling outside the scope of the present invention.

Claims

1. System for producing energy through solar panels (3) with at least one energy-producing unit (1) comprising at least one solar panel (3) , characterised in that it comprises first rotating means (5, 6, 7, 8, 9, 10, 11) for rotating said at least one panel (3) with respect to an axis parallel to a surface of the panel, in such a way as to orientate said at least one panel (3) according to the position of the sun through the day.

2. System according to claim 1, further comprising second rotating means (18, M) for rotating said at least one unit (1) with respect to a substantially horizontal axis, in such a way as to orientate said at least one panel (3) according to the height of the sun on the horizon.

3. System according to claim 1, or 2, wherein said at least one energy-producing unit (1) comprises a frame (2) with a substantially rectangular shape the longer sides of which are reinforced by stiffening elements (4), with an "L"-shaped section, said at least one panel (3) being rotatably connected to said longer sides by a first pin (5) and a second pin (6) located on opposite sides of the panel (3).

4. System according to claim 3, wherein said stiffening elements (4) have a corrugated surface.

5. System according to any preceding claim, wherein said first rotating means (5, 8, 9, 10, 11) comprises a disc (8) at the centre of which there is fixed an end of said first pin (5) , a connecting rod (9) rotatingly coupled with said disc (8) in an eccentric position with respect to said centre, said connecting rod (9) being driven to move with reciprocating movement by a linear actuator (10) the shaft (12) of which is connected to an end of the connecting rod (9) by a sleeve (11) an end of which is connected to said end of the connecting rod (9) .

6. System according to any preceding claim, wherein each energy producing unit (1) comprises a plurality of said panels (3) .

7. System according to claim 6, wherein a distance (D) between two adjacent panels (3) is not less than half a width (L) of said panels (3) .

8. System according to claim 6, or 7, wherein said connecting rod (9) is connected in said eccentric position to each disc (8) associated with each panel (3) .

9. System according to any one of claims 6 to 8, wherein the second pin of each of said panels (3) is fixed to the centre of a further respective disc (13) , the further discs

(13) being connected together in pairs by further connecting rods (14), rotatingly coupled at the respective ends to two further adjacent discs (13) , in an eccentric position with respect to the centre of each further disc (13), each end of said further connecting rods being rotatingly coupled to the respective further disc (13) by a respective coupling pin (15) .

10. System according to claim 9, wherein connecting rods

(14) the ends of further connecting rods (14) adjacent to one another are rotatingly coupled with a further disc (13) in positions diametrically opposite the centre of the further disc (13) .

11. System according to claim 9, or 10, wherein the ends of each further connecting rod (14) are connected to said coupling pins (15) by a first threaded connecting element (16) and a second threaded connecting element (16a) screwed into respective threaded seats obtained in each of said ends.

12. System according to claim 11, wherein said first threaded connecting element (16) and said second threaded connecting element (16a) have opposite threads.

13. System according to any preceding claim, wherein the frame (2) of each energy producing unit (1) is articulated, at two vertices thereof that are adjacent to one another, on respective supporting elements (17) in such a way as to be able to rotate with respect to said supporting elements (17) around an axis (A) substantially parallel to the longer sides of the frame (2) .

14. System according to any preceding claim, said second rotating means (18, M) comprises a pair of lifting elements (18) connected to said frame (2), each lifting element (18) comprising an articulated parallelogram connected at a first vertex to said frame (2) and at a second vertex, opposite said first vertex, to a further supporting element (19) .

15. System according to claim 14, wherein said articulated parallelogram (18) comprises four rods (21, 21a, 21b, 21c) the ends of which are hinged on four connecting elements (20, 20a, 20b, 20c) , a first of said connecting elements (20) being fixed to said further supporting element (19) , a second of said connecting elements (20a) being fixed to said frame (2) .

16. System according to claim 15, wherein said rods (21, 21a, 21b, 21c) have a box section.

17. System according to claim 15, or 16, wherein between a third of said connecting elements (20b) and a fourth of said connecting elements (20c) a linear actuator (22) is arranged.

18. System according to claim 17, wherein said linear actuator (22) comprises a worm (23) , rotated by a driving means (M) through a dual-effect thrust bearing (24), and a hollow cylindrical element (25) , fixed at a first end to another (20c) of said third and fourth connecting elements, and terminating at a second end thereof opposite said first end with a nutscrew sleeve (26) suitable for engaging said worm (23) .

19. System according to claim 18, wherein said driving means is a motor (M) fixed to one (2Od) of said third and fourth connecting elements.

20. System according to claim 18, wherein said driving means is a manual driving crank.

21. System according to any one of claims 18 to 20, wherein an end of the feed screw (23) intended for coupling with the sleeve (26) is provided with a stopping element suitable for preventing the feed screw (23) from leaving the sleeve (26) .

22. System according to any one of claims 3 to 21, wherein with said second pin (6) of said at least a panel (3) there is associated a first rotation sensor (Sl) .

23. System according to claim 22, wherein said first rotation sensor (Sl) is a potentiometer sensor.

24. System according to any one of claims 13 to 23, wherein with said rotating axis (A) there is associated a second rotation sensor (S2) .

25. System according to claim 24, wherein said second rotation sensor (S2) is a potentiometer sensor.

26. System according to any preceding claim, wherein said solar panels (3) are photovoltaic panels.

27. System according to any one of claims 1 to 25, wherein said solar panels (3) are thermohydraulic panels.

28. System according to claim 26, wherein said at least one energy-producing unit (1) is connected to a DC/AC converter (27a, 27b) through an electric line (28a, 28b) provided with an overvoltage limiting device (29a, 29b) .

29. System according to claim 28, wherein said electric line (28a, 28b) is provided with a first circuit-breaking element (33, 33a) suitable for enabling said electric line (28a, 28b) to be disconnected from said at least one energy- producing unit (1) .

30. System according to claim 28, or 29, wherein said electric line (28a, 28b) is provided with a second circuit- breaking element (33, 33a) suitable for enabling said electric line (28a, 28b) to be disconnected from said DC/AC converter (27a, 27b) .

31. System according to any one of claims 28 to 30, wherein on said electric line (28a, 28b) there is provided a current sensor (35) and a voltage sensor (36) .

32. System according to claim 31, wherein said current sensor (35) and said voltage sensor (36) are of digital type.

33. System according to any one of claims 28 to 32, wherein said DC/AC converter (27a, 27b) , is connected through a further electric line (30) to the electrical system (31) of a building or to an energy distribution network.

34. System according to claim 33, wherein on said further electric line (30) there is provided a further overvoltage limiting device (32) .

35. System according to any one of claims 28 to 34, wherein said DC/AC converter (27a, 27b) is provided with a data bus that is connectable to a data-processing system.

36. System according to any preceding claim, associated with a roof (T) of a building, wherein in said roof (T) there is provided at least one seat (38) inside which said at least one energy-producing unit (1) can be made to retract.

37. System according to any preceding claim, wherein said at least one energy-producing unit (1) is associated with a respective electronic card (39) connectable to a data processing system (40), said electronic card (39) the operation of the electric components of the system.

38. System according to any preceding claim, further comprising emergency generator means suitable for supplying the electric components of the system, in particular the linear actuator (10) and the motor (M) .

39. System according to claim 38, wherein said emergency generator means comprises a wind dynamo (51) .

40. System according to any preceding claim, further comprising a data processing system connected to said electronic card (39), said data processing system comprising, or being connected to, a data recording unit (53) on removable supports.

41. System according to any one of claims 37 to 40, further comprising one or more of the following elements, connectable to said electronic card (39) : - rotation sensors (44) for detecting the rotation angle of the shaft (12) of the linear actuator (10) and of the motor (M);

- a pyranometer (45) ;

- anemostat (46) ; - an anemometer (47) ;

- one or more temperature sensors (48); end stroke sensors (49) associated with the linear actuator (10) and the linear actuator (18);

- lubricating means for lubricating moving mechanical parts of the system.