WO2012117142A1

WO2012117142A1 - Solar tracker

Info

Publication number: WO2012117142A1
Application number: PCT/ES2012/070126
Authority: WO
Inventors: Francisco Jose CERON GARCIA; Emiliano Cornago Ramirez
Original assignee: Abengoa Solar New Technologies, S.A.
Priority date: 2011-02-28
Filing date: 2012-02-28
Publication date: 2012-09-07
Also published as: ES2387775A1; US20130333690A1; ES2387775B1

Abstract

Solar tracker that comprises a pedestal (1) to which is affixed a structural support (10) for a reflecting surface (15), which tracker comprises: - a fixed base (2), secured to the ground, which comprises an upper planar surface (7) with an opening; - a rotating mechanical element (3) of a vertical axis, arranged in the opening in the planar surface (7) of the fixed base (2) and are fixed to the pedestal (1); - and a cylinder (4) for triggering azimuthal rotation of the structural support (10), which comprises a first end affixed to the ground by an anchoring means (16, 2) and a second end affixed to the rotating mechanical element (3) by fastening means, the rotating mechanical element being configured in such a manner that, when the triggering cylinder moves, the rotary mechanical element transmits the rotation movement from the second end of the triggering cylinder to the pedestal (1).

Description

SOLAR TRACKER

Field of the Invention

The present invention is included within the field of solar trackers for thermoelectric and photovoltaic applications, and more specifically, solar trackers for solar thermal applications (heliostats, stirling discs, etc.) of rotation in one or two axes: azimuthal and / or of elevation.

Background of the invention

The solar thermal plants are destined to! use of solar energy from the heating of a fluid through solar radiation, and its use in a conventional thermodynamic cycle, for the generation of electrical energy.

The capture and concentration of the sun's rays is done by heliostats. Heliostats are large mirrored surfaces generally shaped with a certain curvature that follow the sun at all times, so that the rays reflected by them, affect at any moment on one or several fixed foci, located on top of a tower, where a receiver is placed, which heats the heat transfer fluid.

The use of solar trackers in the production of photovoltaic solar energy consists of a supporting structure where flat photovoltaic panels are installed. These panels must at all times be oriented perpendicular to the sun's rays for which the follower needs the ability to rotate in e! space following the position of the sun. The photovoltaic cells convert the energy of the sun into electricity which, through wiring and current inverters, directs the energy for industrial or commercial use.

The different mechanisms available so far to provide the supporting structure of azimuthal mobility (with vertical rotation axis) and elevation (with horizontal rotation axis) are the following:

- Carousel model: the structure is provided with a double circular rail through which the structure is moved and thus achieves the desired orientation

- Model "T". There are different models using an endless-crown mechanism in azimuthal rotation and an electromechanical spindle for lifting.

Also, it is used for followers of small sizes, electromechanical spindles for both movements.

The utility model ES1050814 discloses a solar tracker for photovoltaic power plant, which consists of a fixed platform defined by a circular rail supported by pillars that raise it from the ground and keep it level to allow a rotating platform located above and provided with wheels, to rotate to be oriented in azimuth. This turntable is a carrier of a plurality of solar panels arranged in rows and columns on a ramp surface. In turn, each of the rows of solar panels is rotating around an axis common to all of them, to orient from a vertical position in which they receive the sun's rays at dawn, until it acquires the most angled position at noon when the sun is higher. For its part, the azimuth rotation of the mobile platform, simultaneous with the angulation of the plates, is carried out when one of the wheels has a gearmotor coupled, turning up to 210 ° equivalent to fourteen hours of the apparent solar path, from the exit of the star until he fell.

In the utility model ES-A-1059027 a rotating base for solar panel installations is proposed, formed by a circular U-shaped rail, on a fixed platform or bench supported by pillars that place it level according to the orography of the zone to be installed and, defined on the rail, a mobile inclined structure with a plurality of solar panels arranged in rows and columns on this ramp surface. This inclined structure is attached and coupled to the fixed circular rail by means of perpendicular bearings, which give it angular mobility, in addition to serving as a guide to the rotating movement.

Likewise, US6123067 discloses a solar tracker with an azimuthal rotation system by means of two hydraulic cylinders arranged perpendicularly and a lifting system by means of a hydraulic cylinder.

US4459972 discloses a heliostat comprising means of rotation of the reflector arranged on the pedestal and fixed at a fixed or variable distance of the reflector, being used for the case of means of rotation of variable distance to the reflector, a hydraulic cylinder.

The problem detected in the rotation systems of the aforementioned solar trackers is that, in the case of heliostats, the focal length is hundreds of meters, so if known rotation systems are applied to heliostats, it obtains a low capacity to obtain a precise position, that is to say, a low precision, which means that there is a need to develop a specific heliostat turning system with great precision in the movements throughout the day.

Description of the invention

The invention relates to a solar tracker, of those referred to in the section on antecedents as of type ", which includes a pedestal, cylindrical or parallelepiped, on which a supporting structure or structural support of mirrors or photovoltaic modules is fixed, which solves the aforementioned problems by:

- a fixed base anchored to the ground, comprising a flat top surface with an opening,

- a rotating vertical axis mechanical element disposed in the opening of the flat surface of the fixed base and fixed to the pedestal, and

- an azimuthal rotation actuator cylinder of the structural support, comprising a first end fixed to the ground by an anchoring means and a second end fixed to the rotating mechanical element by fixing means, the rotating mechanical element being configured such that when the actuator cylinder executes its movement, the rotating mechanical element transmits the rotational movement of the second end of the actuator cylinder, to the pedestal (1)

Specifically, the solar tracker of the invention comprises:

- a fixed base anchored to the ground, which may comprise at least one side opening and a flat top surface with an opening,

- a rotating vertical axis mechanical element, arranged in the opening of the flat surface of the fixed base, comprising a fixed ring fixed to the fixed base and a movable ring on whose upper face the lower end of the pedestal is fixed,

- an oleohydraulic cylinder azimuthal rotation actuator which. it comprises a first end fixed to the ground or to the fixed base of the follower by anchoring means and a second end fixed tangentially to the lower face of the moving ring of the mechanical element by fixing means. This, through a common hydraulic switchboard, transforms the linear movement, lengthening or shrinking, into a rotating movement of the pedestal greater than 120 °,

- optionally a second cylinder can be used comprising a first end fixed to the ground or the fixed base of the follower by means of anchoring and a second end tangentially fixed to the lower face of the moving ring of the mechanical element by a mobile fixing means to which the second end of the first cylinder is also anchored, so that an azimuthal rotation of 315 ° is obtained.

Pedestal is understood as a solid body, cylindrical or rectangular parallelepiped, which supports a structure. Understanding by body solid to a firm body not necessarily solid.

The means for anchoring the first end of each cylinder to the ground comprise:

- a base fixed to the ground, or to the fixed base of the follower, by means of anchoring, such as anchor bolts, with a circular opening or drill,

- a piece, parallel to said base, with a coaxial circular opening and concentric to the opening or hole in the base,

- a piece located between the base fixed to the ground and the part parallel to said base, perpendicular to both, the piece being parallel to the base at a distance such that it allows to place, between the base and the parallel piece, the ball joint of the hydraulic cylinder , Y

- a vertical fixing axis, such as a bolt, which crosses the holes or openings, of the base and [a parallel piece, and the ball joint.

The azimuthal movement of solar trackers with a cylinder takes place because the cylinder extends or retracts, causing a rotating movement of its second end fixed to the rotating mechanical element. Said circular movement has as its center the axis of rotation of the rotating mechanical element, which can be a bearing or a crown of rotation, and as a radius the distance from this point to the center of the rod or piston of the cylinder integral with the pedestal. The circular path is in a horizontal plane. The cylinder will therefore have a rotational movement of the second end of the axis and a rotational movement of the axial line of the cylinder around the mooring point to the ground to absorb the previous movement. In this case, a turning capacity greater than 120 ° is achieved.

The azimuthal movement with two cylinders takes place because the two cylinders are anchored at their second end to an anchoring means fixed to the rotating mechanical element such that the line joining these two points, corresponding to the second ends of each cylinder, passes through the center of rotation of the pedestal. Hydraulic cylinders, when extended or retracted, cause a rotating movement of its end, forced by the rotating mechanical element. Said circular movement has as its center the axis of rotation of the rotating mechanical element and as a radius the distance from this point to the center of the rod integral with the pedestal. The circular path is in a horizontal plane. When the cylinders are extended or retracted they cause the structure to rotate with a capacity of 315 °. Both cylinders must be synchronized so that e! direction of rotation they cause coincides in each moment.

On the other hand, the solar tracker of the invention comprises a system of elevation of the structural support fixed to the upper end of the pedestal, comprising:

- A support element or upper bench comprising two joints for the lifting movement of the structural support, which supports the reflective surfaces or photovoltaic panels,

a lifting cylinder anchored to the pedestal by a first end by means of a fixed anchor comprising a kneecap, and anchored by a second end to the arm or mobile structural support! of support of the reflective surfaces or photovoltaic modules, by means of an anchor point to the patella of the second end of the cylinder

The lifting cylinder, through its line! Movement of elongation or retraction, causes the rotary movement of the mobile structural support with respect to the pedestal. '

The mobile structural support includes the mirrors or photovoltaic panels to be oriented.

Thus, the lifting movement takes place when the hydraulic lifting cylinder extends or retracts, causing a rotating movement of its end, forced by the spindle-type clamping of the support element of the mobile structural support with respect to the pedestal. Said circular movement occurs in a vertical plane that passes through the anchor point of the first end of the cylinder. Its center is the point of intersection of the axis of rotation or horizontal line that passes through the centers of the previous kneecaps with the vertical plane defined above. The turning radius of the movable kneecap of the lifting cylinder will be the distance between the anterior center and the movable anchor point.

It is evident that the anterior vertical plane is not fixed, together with the pedestal, and the plane of mirrors or plates, revolves around the vertical axis of the base bearing thanks to the azimuth rotation mechanism explained above.

Hydraulic cylinders can be optimized using cylinders with a diameter range between 120-240 mm.

The rotating mechanical element can be optimized using a rotating mechanical element with a radius greater than 700mm.

Additionally, the solar tracker of the invention comprises in e! pedestal: a hydraulic switchboard or oil supply system to the cylinders, comprising a motor-pump group that confers pressure on the hydraulic system, an oil reservoir to admit the loading and unloading of oil from the cylinders hydraulic, a braking and blocking block to regulate the speed of the cylinders, a maneuvering block to handle the mechanism, pressure accumulators for a rapid response of the system; and pressure switches, solenoid valves, special vanities, hoses and traverses, whose mission is to supply oil under pressure to the cylinder chambers.

Likewise, fixed on the pedestal, the follower comprises a control system that feeds the pump, orders the opening and closing of the oil circuits, captures the position and status information of the follower, communicates it with the centralized control and enables local control The system comprises an external box that has a console inside for the configuration, calibration, monitoring and diagnosis of the system; a keypad for maintenance and cleaning functions of the follower, a power block to manage the power supply of the electric group, and a communications block to manage all the information that comes from the centralized control, the keypad and the status of the follower.

■ The solar tracker of the invention comprises a mechanism of azimuthal rotation and elevation of the structural support of the mirrors or photovoltaic panels that are to be oriented, with great advantages over the known mechanisms since:

- By placing the turning mechanism at the base of the pedestal, a larger turning radius is available, which translates into high precision and we obtain high quality at the follower point.

- By placing the azimuthal rotation system at the base, great material savings are also achieved by not needing a complex bearing structure to support the height rotation system.

- When the azimuthal rotation is transferred to the base of the structure, the height of an off-center weight is reduced, saving on the dimensioning of the foundation.

- The bearing on the base does not entail extra cost because it gives the system the precision necessary for its orientation, and the diameter is not greater than the dimensions of the elements that it joins.

- Another advantage of the invention is that space is freed around the lifting cylinder for its operation and maneuverability, as well as for accommodating limit switches, position measuring devices ...

- This ensures that the radius of rotation of the piston rod or piston of the lifting cylinder is greater and thus achieve greater precision in vertical movement. - In the cost-quality ratio, a higher quality is achieved by the points indicated above with a considerable decrease in manufacturing cost and greater reliability.

- The use of hydraulic cylinders in a diameter range optimized for this invention means an improvement in sun tracking, since very small and precise movements are achieved

Additionally, it should be noted that the cylinders can be oleohydraulic or also mechanically driven, in which case the hydraulic power plant installed on the pedestal would not be necessary.

Brief description of the drawings

A series of drawings that help to better understand the invention and that expressly relate to an embodiment of said invention which is presented as a non-limiting example thereof is described very briefly below.

Figure 1 shows a diagram of a solar tracker with a single azimuthal hydraulic actuator cylinder.

Figure 2 shows a diagram of a solar tracker with two hydraulic cylinders azimuthal rotation actuator.

Figure 3 shows a perspective detail of the solar tracker pedestal with the hydraulic control equipment and the oil supply equipment

Figure 4 shows a perspective view of a detail of the upper bench.

Figure 5 shows a bottom view of Figure 1,

Figure 6 shows a bottom view of figure 2.

Figure 7 shows a perspective detail of the fixed anchorage of the oleohydraulic cylinder of azimuthal rotation drive.

Figure 8 shows a side scheme of the lower part of the solar tracker with an oleohydraulic cylinder and U-arm fixed to the base of the pedestal.

Figure 9 shows a section on IX-IX of Figure 8.

In the aforementioned figures, a series of references are identified that correspond to the elements indicated below, without implying any limiting character:

1.- Pedestal

2 - Fixed base

3.- bearing 4 - azimuthal hydraulic cylinder

5. - mobile anchor

6. - side openings

7. - flat surface of the fixed base

8. - fixed outer bearing ring

9. - mobile inner bearing ring

10. - reflective surface support arm

1 1. - hydraulic lifting cylinder

12. - upper bench

13. - first anchor of the first end of the lifting cylinder

14. - second anchor of the second end of the lifting cylinder

15. - reflective surface

16. - fixed azimuthal rotation cylinder anchor

17. - cartouche

18. - horizontal axis of rotation of the reflective surface

19. - articulation of the upper bench

20. - hydraulic control equipment

21. - pressurized oil supply system to the cylinders

22. - fixed support

23. - base of the fixed anchor of the azimuthal rotation cylinder

24. - parallel part of the fixed anchor of the azimuthal rotation cylinder

25. - perpendicular piece of H profile

26. - U-arm

Detailed description of one embodiment

As can be seen in Figures 1, 3, 4 and 5, the solar tracker of the invention is a heliostat comprising:

- a fixed base (2) anchored to the ground, comprising a lateral opening (6) and a flat upper surface (7) with an opening,

- a bearing (3) as a rotating vertical axis mechanical element, preferably with a radius greater than 700mm, arranged in the opening of the flat surface of the base of the pedestal, comprising an outer ring (8) fixed to the fixed base and a inner ring (9) movable,

- a pedestal (1) fixed to the upper face of the inner moving ring (9) of the bearing, and on which an arm (10) is fixed as a structural support of reflective surfaces

- an oleohydraulic cylinder (4) azimuthal rotation actuator comprising a first end fixed to the ground by an anchoring means (16) and a second end fixed tangentially to the underside of the inner moving ring (9) of the bearing by fixing means .

- an upper bed (12) comprising two joints (19, 19 ') for the lifting movement of the structural support or arm (10) that supports the reflective surfaces or photovoltaic panels,

- an oleohydraulic lifting cylinder (11) anchored to the pedestal (1) by a first end by means of a first anchor (13) comprising a ball joint, and anchored by a second end to the arm (10) of the reflective surfaces (15) by means of a second anchor (14) to the kneecap of said end of the cylinder.

- a supply system (21) of pressurized oil to the oil-hydraulic cylinder (4, 11)

- a control equipment (20) for the pressure of the pressurized oil supply system (21).

Figures 2 and 6 show another preferred embodiment in which the fixed base (2) of the hauostat comprises two lateral openings (6, 6 ') faced with two hydraulic cylinders of azimuthal rotation (4, 4') so that the second end of each cylinder (4, 4 ') is fixed tangentially to the underside of the mobile inner ring (9) of the bearing by a movable anchoring piece (5) as a movable fixing means, so that an azimuthal rotation of 315 °.

Figures 8 and 9 show a preferred embodiment in which the fixed base (2) anchored to the ground also comprises a U-arm (26) to which the end of the cylinder (4) is fixed, two U-arms being able to comprise when the base (2) comprises two openings (6, 6 ') and two cylinders (4, 4').

Figures 1-3, 5 and 6 show embodiments in which the anchoring means (16, 16 ') of the first end of each oleohydraulic cylinder of azimuthal rotation to the ground, as shown in Figure 7, comprises :

- a base (23) fixed to the ground, by bolts, with a circular opening or drill,

- a piece (24), parallel to said base, with a coaxial circular opening and concentric to the opening or hole in the base, - a small piece of boilerwork located between the base (25) and the part parallel to it, with an H-profile, thus allowing a distance between them to be placed between the base and the parallel part, the cylinder head hydraulic, and

- a fixing bolt that crosses the holes or openings, of the base and the parallel piece, and the ball joint.

The parallel piece, as can be seen in Figure 7, is fixed to an H-profile perpendicular to the base, although it could have any profile capable of fixing the piece parallel to the desired distance from said base.

Additionally, the solar tracker of the invention comprises on the pedestal a pressurized oil supply system (21) to the hydraulic cylinders (4, 4 'and 1 1) in diameter in the range of 120-240 mm comprising a motorcycle group -Pump, an oil tank, cylinder speed regulating means and oil supply means.

Also fixed on the pedestal the follower includes a control equipment

(20) of the oil supply system (21), which includes means for configuration, calibration, monitoring, diagnosis and management of the system operating parameters supplied with oil (21)

In figure 3 a detail of the pedestal of the follower of the invention can be seen with the oil supply system (21) and the control equipment (20). In figure 4 a detail of the upper bench (12) can be seen in which it can be seen that it comprises two articulations (19, 19 ') each comprising two swiveling brackets (17, 17') attached to the arm or support structural (10) with a fixed support (22, 22 ') arranged between them and joined to them by a horizontal axis of rotation (18, 18') of the structural support

Claims

1- Solar tracker comprising a pedestal (1) on which a structural support (10) of a reflective surface (15) is fixed, characterized in that it comprises:

- a fixed base (2) anchored to the ground, comprising a flat upper surface (7) with an opening,

- a rotating mechanical element (3) with a vertical axis arranged in the opening of the flat surface (7) of the fixed base (2) and fixed to the pedestal (), and

- a cylinder (4) azimuthal rotation actuator of the structural support (10), comprising a first end fixed to the ground by an anchoring means (16, 2) and a second end fixed to the rotating mechanical element (3) by means of fixation,

the rotating mechanical element being configured in such a way that when the actuating cylinder executes its movement, the rotating mechanical element transmits the rotational movement of the second end of the actuating cylinder, to the pedestal (1).

2. Solar tracker according to claim 1 characterized in that the rotating mechanical element comprises a fixed ring (8) fixed to the fixed base (2) and a mobile ring (9) comprising an upper face to which the lower end is fixed of the pedestal (1), and a lower face to which is fixed to the second end of the actuator cylinder (4).

3. - Solar tracker according to claim 2 characterized in that the fixed base (2) anchored to the ground comprises a lateral opening (6).

4. - Solar tracker according to claim 3 characterized in that the actuator cylinder is arranged under the flat surface (7) of the fixed base (2) anchored to the ground and through the lateral opening (6).

5. - Solar tracker according to claim 4 characterized in that the fixed base (2) comprises a second lateral opening (6 ') facing the first opening (6).

6. - Solar tracker according to claim 5 characterized in that it comprises a second cylinder (4 ') disposed under the flat surface (7) of the fixed base (2) anchored to the ground and passing through the second lateral opening (6'), which comprises a first end fixed to the ground by an anchoring means (16 ', 2) and a second end fixed tangentially to the lower face of the movable ring (9) of the mechanical element (3) by a movable anchoring piece (5) to which the second end of the first cylinder (4) is also anchored.

7 - Solar tracker according to previous claims characterized in that it comprises a lifting cylinder (11) anchored to the pedestal (1) by a first end by means of a first anchor (13), and anchored by a second end to the structural support (10) of the reflective surfaces (15) by means of a second anchor (14).

8. - Solar tracker according to previous claims characterized in that it comprises an upper bed (12) fixed to the upper end of the pedestal (1) comprising a rotating system with respect to a horizontal axis (18, 18 '), fixed to the structural support (10 ), operable by the second end of the lifting cylinder (1 1).

9. - Solar tracker according to claim 8, characterized in that the rotating system comprises two articulations (19, 19 ') each comprising two rotating hinges (17, 17') fixed to the structural support (10) with a fixed support (22, 22 ') arranged between them and joined to them by a horizontal axis of rotation (18, 18') of the structural support (10).

10. - Solar tracker according to previous claims characterized in that the cylinders are oleohydraulic cylinders.

11. - Solar tracker according to claim 10 characterized in that it comprises a system supplied (21) of pressurized oil to the oleohydraulic cylinders (4, 4 'and 11) comprising a motor-pump group, an oil tank, regulating means of speed of cylinders and oil supply means.

12. - Solar tracker according to claim 11 characterized in that it comprises a control equipment (20) for the pressure of the pressurized oil supply system (21) comprising means for configuration, calibration, monitoring, diagnosis and management of the parameters of system performance supplied with oil (21)

13. - Solar tracker according to previous claims characterized in that the anchoring means (16, 16 ') comprises:

- a base (23) fixed to the ground by anchoring means, with a circular opening or drill,

- a piece (24), parallel to said base, with a coaxial circular opening and concentric to the opening or hole in the base,

- a piece perpendicular to the base (25) and the part parallel to the base located between the two, on which the piece parallel to the base is fixed, at a distance such that it allows to place, between the base and the parallel piece, the hydraulic cylinder head, and

- a vertical axis of fixation that crosses the holes or openings, of the base and the parallel piece, and the patella.

14. - Solar tracker according to claims 1-12 characterized in that the ground anchor means comprises the fixed base (2) anchored to the ground.

15.- Solar tracker according to claim 14 characterized in that the fixed base (2) It comprises at least one U-arm (26).

16.- Solar tracker according to previous claims characterized in that the rotating mechanical element is an element selected from bearing or rotating crown.

17.- Solar tracker according to claims antennas characterized in that the hydraulic cylinders have a diameter between 120-240 mm.

18.- Solar tracker according to previous claims characterized in that the radius of the rotating mechanical element is greater than 700mm.