ES2334187B1 - SOLAR FOLLOWER OF THREE AXLES OF LARGE SURFACE. - Google Patents

Abstract

Large-area three-axis solar tracker, which it uses to focus two zenithal axes of rotation and one azimuth. The solar tasters (3) are arranged in inclined rows that can rotate as an adjustable grid with respect to the chassis (2) in which support the chassis (2) scales, by means of two cylinders (5), on a structure formed by four arms (6) converging to a Troncopiramidal Castillete (7), as a knot, bolted by its upper base to a motorized bearing (8) supported on a column (9), to achieve its azimuth approach; in which the castillete (7), embedded in column (9), minimizes moments on the bearing (8); and in that the combination of the two zenith drives are programmed to focus, avoiding shadows between sensors, at minimum chassis height.

Description

Large three-axis solar tracker surface.

Object of the invention

The invention, as expressed in the statement, is refers to a large-area three-axis solar tracker that it brings to the function to which considerable and essential advantages are destined features, which will be described in detail later in the present descriptive report, and that represent an innovative improvement to what is already known in this field.

More specifically, the object of the invention consists of a new concept of solar tracker that through systems that govern the solar path, it is used to improve the production of solar collectors, which through combination of two zenith movements and one azimuthal one gets focus, with minimum heights on the ground, minimizing cast shadows, which allows to project solar fields with minimum occupied area, increasing the density of installed power per square meter occupied and reducing the visual impact.

The possibility of focusing large areas to low ground height, advantageously decreases efforts of the wind over the structure and terrain, which allows us run large-area followers of specific cost more low.

Scope

The field of application of the present invention It is the design of large solar parks and allows development industrial sustained over time in the manufacture of this type of structures

Background of the invention

The entry into force of RD 436/2004 has led to a considerable increase in requests for solar installations with a power equal to or less than 100 kW. so much photovoltaic as thermal, the latter without limitation of power, connected to the network.

The promoters, in the case of photovoltaic, group different holders in a single park sharing a single network connection point and benefiting from lower installation and operation costs, having unified the management, with a single evacuation point, is what we call "Solar park".

Currently, some solar parks they exceed 5 MW, with some up to 20 MW being planned.

For reasons of production optimization, in a country like Spain (40º parallel) installation is recommended of solar collectors on structures equipped with monitoring solar called "solar trackers".

These structures can follow the path of the sun in a plane parallel to the ground (azimuth axis), or in two parallel and perpendicular planes to the ground (azimuthal + zenith).

The former provide a gain of approximately 30% and the latter 40%, depending on the latitude and climatic conditions of the place.

\euro

/vatio pico) se amortice en dos o tres años antes que en una instalación fija.It is common to almost all these facilities than the over cost introduced by the follower (1

 \euro 

/ watt peak) pays for itself in two or three years before a fixed installation.

The inconvenience of the facilities with solar tracking, compared to fixed, is the need for greater occupied spaces, to avoid shaded spaces.

In ortho and sunset, the sun is tangent to the Earth's surface and therefore causes, on a projecting object, An almost infinite shadow.

As the sun rises, the shadows cast by the object are reduced depending on the cosine of the angle of incidence.

At noon, when the sun is in the south, its height is maximum and therefore the shadows cast are minimum

In order to minimize the shadows cast, solar park designers must keep a distance between followers that are a direct function of the height of the structures

The normal thing is to place them in rectangular implantation frames " with four golds " with lights, including three times their height in the NS direction and five times their height in the EO direction.

This means occupying surfaces close to 10 Have by Mw (megawatt) when the park is projected with followers small (5 Kw), and 5 hectares. by Mw when the park is projected with 25 Kw followers per unit.

It is clear, then, that the big followers minimize the occupied land and all the facilities attached to they (shoes, ditches, fences, wiring length, etc.), by what, at the present moment, the market is demanding, each Again, big followers.

It should be noted that many are the manufacturers that offer small followers, but few offer followers between 25 and 30 Kw per unit.

The limitation that followers have, Regarding its size, it is wind safety. Let's think that, in the state of current technology, the performance of sensors range from 12 to 17%, that is, a square meter of collector can provide between 120 and 170 watts.

This means that to get 5 Kw you they would need between 42 and 30 square meters of surface collector, and that to add 100 Kw would require between 600 and 840 square meters of surface.

These large rotating surfaces should be very well projected, from the point of view of security against winds, besides being easy to manufacture, transport and mount.

In any case, it should be low height, to minimize the shadows cast and consequently the occupied surfaces

Get follower structures like the indicated is the object of the present invention.

On the other hand, within the field of energy solar thermal, we must differentiate flat solar collectors, for hot water production, of the collectors of concentration for mechanical power generation, in the form of torque x rotation speed on the turbine shaft, capable of driving generators, pumps or other elements.

Within the latter, we will deal with the parabolic trough concentrators focused on mirrors aligned on structures whose focal line is installed a pipe through which a thermal fluid flows.

So far, these concentrators they are installed directly on the ground in lines that can swing on a single E-W axis, wasting Too many solar hours for lack of a correct approach.

As an example we will quote that to produce 1.3 Mw thermal a row of collector mirrors of 55 is needed 0m long and 2750m2 of solar collection surface, to produce 0.8 Kg / s of steam at 100 bar and 370ºC (See project DISS-Almería Solar Platform).

Keep in mind that in parallel 40 the day June 21 the sun travels 242 degrees azimuthal and 73 degrees zenitially, which clearly indicates the gain would obtain if this type of facilities were located on followers.

Get great structures that carry solar collectors, either panels or concentrators, within the minimum occupied space, is one of the objectives of the solar tracker of three large-area axes advocated by this invention, of which, on the other hand, it should be noted that the petitioner is unaware of the existence of any other who presents technical, structural and constitutive characteristics similar.

Explanation of the invention.

Thus, the large three-axis solar tracker surface that the invention proposes, constitutes by itself a evident novelty within its field of application, since under its application is achieved in a taxable way to improve the production of solar collectors, given that through combination of the two zenith movements and the azimuthal that presents, manages to focus, with minimum chassis heights, minimizing the shadows cast, which allows projecting fields plots with minimal occupied surface, increasing the installed power density per square meter occupied and reducing the visual impact.

Specifically, in the follower of the invention, which as mentioned used to focus two axes of rotation zenithal and one azimuthal, the solar collectors are arranged in inclined rows that can rotate as an adjustable grid regarding the chassis they rely on.

This chassis scales, using two cylinders, on a structure formed by four arms converging to a Troncopiramidal castor, as a knot, bolted by its base superior to a motorized bearing, supported on a column, to get your azimuth approach.

The aforementioned castile, embedded in the column, minimizes the moments on the bearing.

The combination of the two drives zeniths are programmed to focus, avoiding shadows between sensors, at minimum chassis height, thus reducing shadows thrown and the visual impact, needing less surface to Run the solar park.

It should be noted that this design has passive safety against network cuts, gales or anomalies, when adopt the most lying position, protecting yourself weight.

It should be mentioned, that the size of the follower Actual projected is 100 kW, for applications photovoltaic, since this power coincides with the maximum limit of individual facilities to get the best price, according to Royal Decree 463/2004.

In this way, based on the performance of a good quality photovoltaic panel is around 17%, that is, 170 watts per m2 of panel for solar radiation 1000 watts m2 at 25 ° C, and bearing in mind that losses ducts are 2%, temperature losses 5% and the inverter another 5%, the peak power to be installed would be 100,000 / 0.98x0.95x0.95 = 113,064 watts, which translated to surface of grill would be 113,604 / 170 = 665 m2. Taking into account the necessary spaces between panels to place the elements of fixing more clearances by shading, estimated at 5% more than surface, the clipboard grill should have 665x1.05 = 698 m2.

If a rectangular surface is projected whose side has 24 m (to be built with standard long beams of 12 m) the length of the rows would be 689/24 = 28 m.

It is about projecting a structure giant capable of supporting a surface area of 698 m2 rectangular, approximately 24x29 m, which with the minimum height Possible to focus on the sun.

The limits that are imposed from the start, for the dimensioning of unit parts, are imposed due to their transportability by road, that is, their maximum width will not exceed 2.55 m and their maximum length is 13.6 m (maximum length of a semi-trailer or trailer plus 1 m of cantilever allowed), therefore 14.6 m in length.

Then, to get the 29 m length of row on the grill, we will join two sections of 14.5 m.

In working position, at sunrise or at sunset, the follower will be with the hydraulic cylinders extended and the grill at 30º with respect to the horizontal.

The chassis support the rows of panels staggered

The rows are calculated as 29 m armed beams long leaning on the chassis, with its cantilever ends, capable of supporting both the weight itself and the panels, more dynamic wind load both windward and leeward.

The four arms on which the chassis, are calculated as recessed beams that support the weights and the thrusts of the wind on the grill.

These arms converge, as has been said, on a truncated pyramid, attached to their faces by each flanges, each of which enters the castor compression loads, shear and moments to be taken present in its dimensioning.

For the determination of wind overloads, the " Fluent " program has been used simulating wind and windward and leeward actions for different angles of incidence on the grid.

For the tensional analysis and determination of thicknesses, simulation by finite elements has been performed.

It is important to note that the castor is embed on the column, bolted by its upper base against a carved bearing to get your azimuthal focus through two sprockets driven by two gearmotors with brake, the which are located on a bridge moored to the fixed ring of the  bearing that bolts into the top flange of the column.

As the follower, in his azimuthal sweep never get to take a full turn, this bridge can be located in any 360º position of the aforementioned ring, so standardize the wear of the movable bearing ring teeth throughout the 30 years of its useful life.

For the dimensioning of the tooth module as well as for the determination of the power of the motors and the engine brake suit, the " Fluent " method has been used for the determination of the center of moments of the pick-up grid as well as the coefficients of moments for different angles of incidence of lateral wind.

The criteria followed for the tare of the brakes is that in no case exceed the tangential effort allowed on the gear tooth.

In an extraordinary wind, the brake must slide, as a torque limiter, letting it drag to follower stealing it.

The lower base of the truncated pyramid it will have 2550 mm side to be transported within the Allowed limits

The two hydraulic cylinders are fixed to the arm ends by oscillating flange. The stems of great length, they are calculated to buckling with the own loads plus the windward wind component.

These cylinders are attached to the chassis by pin and ball that allows them to oscillate and align, constituting This mechanism is the first axis of the zenith drive.

In the design of the chassis the support of the grille holder-collector, such so that the weights on them match the component vertical wind thrust at leeward at 40 m / s, for ensure that the grill will descend by its own weight when the wind approaches this value.

So, we will have passive security against the wind, such that before anomalies of any kind, the grill can lie down and protect itself by its own weight.

On the chassis are fixed oscillatingly collector holder rows, which can be thermal panels, photovoltaic or parabolic trough concentrators.

The sensors are grouped in rows lying down on longitudinal trusses that can range up to about 30º, regarding a embulonado support, located on the chassis, by the action of two hydraulic cylinders, this being the Second axis of zenith drive.

The control of said oscillation is performed by encoders or potentiometers.

Finally, to the set of rows of collectors and chassis we call it grill. The possibility of combining two types of zenith drive described, together with the azimuthal, allows us to achieve a correct approach at minimum height of grill, minimizing both cast shadows and the visual impact

The new large three-axis solar tracker surface, equipped with these two overhead drives together with the azimuthal, therefore, represents a structure Innovative structural and constitutive features unknown so far for that purpose, reasons that together with its practical utility, provide it with sufficient foundation to obtain the exclusivity privilege requested.

Description of the drawings

To complement the description that is being performing and in order to help a better understanding of the characteristics of the invention, is attached herein descriptive, as an integral part of it, of a game of planes, in which with an illustrative and non-limiting nature, represented the following:

Figure number 1.- Shows a view of profile of the follower, according to the invention, corresponding to the position in ortho and sunset of the sun with the grill raised and the extended cylinders.

Figure number 2.- Shows a view of profile of the follower corresponding to the noon position solar in summer, with the grill lying down and the cylinders collected, coinciding with the night position and protection against winds or anomalies.

Figure number 3.- Shows a view in follower plant in whose center you can see the four arms convergent in the central castor and the union of these to chassis, in whose lower half the use of parabolic trough collectors and the use of flat, photovoltaic or thermal sensors.

Figures number 4 and 5.- Show respective detailed views of the union between the arms and the castor of the follower.

Figures number 6 and 7.- Show paths detailed views of the coupling and actuation of sensors parabolic trough to the follower chassis in respective noon and sunset or ortho sun positions.

Figures number 8 and 9.- Show paths detailed views of the alternative coupling to the chassis of flat sensors, also appreciating their drive, respectively, in midday sun positions and sunset or ortho.

Preferred Embodiment of the Invention

In view of the aforementioned figures and of according to the numbering adopted, you can see in them a preferred embodiment of the three-axis solar tracker large area comprising the parts indicated and described below.

In this way, and as seen in these figures, the follower (1) in question is essentially constituted from a chassis (2) on which a plurality of solar collectors (3), arranged in inclined rows that can turn as an adjustable grid that we call grill (4).

Said chassis (2) scales, by means of two cylinders (5), on a structure formed by four arms (6) convergent to a truncated pyramid (7), as a knot, bolted by its upper base to a motorized bearing (8), supported on a column (9), to achieve its azimuth approach, as seen in figure 1, in which it has been represented a profile view of the follower (1) in working position, to the sunrise or sunset, that is, with hydraulic cylinders (5) extended and the grill (4) inclined at 30º with respect to the plane horizontal.

Figure 2 corresponds to the position that adopt the follower (1) at solar noon in summer, with the grill (4) lying down and the cylinders (5) collected, said position being coincident with the night and wind protection or anomalies

Figure 3 shows a plan view of the follower (1), whose center shows the four arms (6) convergent in the central castile (7) and the union of these to the chassis (2), having been represented in the lower half of the follower (1) the use of parabolic trough collectors (3) and in the upper half employing flat (3 ') collectors, photovoltaic or thermal.

In figure 4 you can see, in a detail in section, the assembly assembly of the arms (6), with flanges (10), to the upper base of the truncated pyramid (7), incorporating ratchet lugs (11), carved bearing (8) for azimuth drive, as well as gearmotors (12), a lower flange (13) reinforcing the castor (7), the column (9) and the tie flange (14) of the column (9) to the shoe (fifteen).

In figure 5 it can be seen in a view in floor, the assembly assembly of the arms (6) to the castor (7), incorporating anchor bolts (16) between the castor (7) and bearing (8), as well as the location of the bridge (17) that serves as gearmotor support (12).

Figure 6 shows a detail of the coupling from the parabolic trough sensors (3), to the chassis (2) and its rotating drive in which you can see the mirror parabolic (18) comprising, and its focal tube (19) mounted on the armed structure (20), which driven by the cylinder (21) oscillates focusing on the mooring and bolt (22) and transmits this oscillation to the set of rows of sensors (3) thanks to the articulated tensioner connecting rods (23) to which they are attached the mentioned structures (20).

Figure 6 shows the sensors in position solar noon in summer, appearing as the cylinder (21) is extended, while in figure 7 you can see the previous set with the cylinder (21) collected, corresponding to the position near the solar ortho and sunset.

In figure 8, on the other hand, a detail of the alternative mounting to the solar tracker (1) of collectors (3 ') planes, to the chassis (2), showing in said figure its rotary drive in which said sensors (3 ') are they are glued to a rotating structure (20 ') supported articulated on a support bolt (22) capable of oscillating thanks to the cylinder (21), transmitting said oscillation to the rest of rows of sensors (3 ') thanks to the set of connecting rods with tensioner (23), being, in this figure 6, the assembly represented in solar noon summer position, position that matches the nocturnal and protection against winds or anomalies, and in the Figure 7, the same assembly represented with the cylinder (21) collected corresponding to the position near the ortho and sunset solar.

In this way, and in a summary way, the Castile (7) is embedded in the column (9), bolted by its upper base against a carved bearing (8) to get your azimuthal approach through two pinions moved by two gearmotors (12) with brake, which are located on a bridge (17) moored to the fixed bearing ring (8) that is bolts on the top flange of the column (9).

As the follower (1), in his azimuthal scan never goes for a full turn, this bridge (17) can be located in any position of the 360º, in order to standardize the wear of the teeth of the mobile bearing ring (8).

The two hydraulic cylinders (5) are fixed to the ends of the arms (6) by oscillating flange (24). Their stems (5a), of great length, are calculated to buckling with the own loads plus the windward wind component.

Said cylinders (5) are attached to the chassis (2) by bolt and ball head (25) that allows them to oscillate and align, constituting this mechanism the first axis of the drive zenithal

In the design of the chassis (2) the grille supports (4) collector holder, such so that the weights on them match the component vertical wind thrust at leeward at 40 m / s, for ensure that the grill (4) will descend by its own weight when the wind approaches this value.

Thus, the follower (1) has a passive safety against the wind, so that before anomalies of any type, the grill (4) can lie down and be protected by its own weight, since in addition, the criteria followed for the suit of the brakes is that in no case exceed the effort tangential allowed on the gear tooth, so that before an extraordinary wind, the brake must slide, as a torque limiter, letting it follow the follower (1) Steering it.

On the other hand, on the chassis (2) they are fixed oscillating shape the rows of sensors (3), which has been described above can be thermal photovoltaic panels (3 ') or parabolic trough concentrators (3), are grouped in rows lying on longitudinal trusses that can range up to about 30º, regarding a embulonado support (22), located on the chassis (2), by the action of two hydraulic cylinders (21).

The control of said oscillation is performs by encoders or potentiometers, constituting this the Second axis of zenith drive.

Describe sufficiently the nature of the invention, as well as how to put it into practice, is not considers it necessary to broaden his explanation so that any subject matter expert understands its scope and advantages that derive from it, stating that, within its essentiality, may be implemented in other forms of embodiment that differ in detail from that indicated by way of example, and which will also achieve the protection that collects as long as it does not alter, change or modify its principle fundamental.

Claims (10)

1. Large-area three-axis solar tracker, of the type that by means of systems that govern the solar path, is used to improve the production of solar collectors, characterized by the fact that it uses two zeniths and one azimuthal axis to focus , whose combination manages to focus, with minimum chassis heights, minimizing the shadows cast, being able to project solar fields with minimal occupied surface and increase the installed power density per square meter occupied; in which the solar collectors are arranged in inclined rows that can rotate as an adjustable grid with respect to the chassis on which they rest; and in which said chassis tilts, by means of two cylinders, on a structure formed by four arms converging to a truncated pyramid, as a knot, bolted by its upper base to a motorized bearing, supported on a column, to achieve its azimuthal focus; in which the castor, embedded in the column, minimizes the moments on the bearing; and in that the combination of the two zenith drives is programmed to focus, avoiding shadows between sensors, at minimum chassis height. 2. Three-axis solar tracker of large area, according to claim 1, characterized in that in working position, at sunrise or sunset, the follower will be with the hydraulic cylinders extended and the grill at about 30 ° respect to the horizontal; because the chassis support the rows of staggered panels. 3. Large three-axis solar tracker, according to claims 1 and 2, characterized in that the four arms on which the chassis is articulated, are calculated as recessed beams that support the weights and wind thrusts on Grill; and because these arms converge, on a truncated pyramid castile, joined to their faces by means of two flanges, each of which introduces compression loads, shears and moments into the castor. 4. Large-area three-axis solar tracker, according to claims 1 to 3, characterized in that the castor is embedded in the column, bolted by its upper base against a carved bearing to achieve its azimuthal focus through two sprockets driven by two gearmotors with brakes, which are located on a bridge moored to the fixed bearing ring that bolts to the top flange of the column. 5. Large-area three-axis solar tracker, according to claims 1 to 4, characterized in that the bridge can be located in any position of the 360 ° of said ring, in order to standardize the wear of the teeth of the mobile ring of the Bearing. 6. Three-axis solar tracker of large surface area, according to claims 1 to 5, characterized by the fact that before an extraordinary wind, the brake slides, as a torque limiter, allowing it to drag the follower by wheeling it. 7. Three-axis solar tracker of large surface area, according to claims 1 to 6, characterized in that the two hydraulic cylinders are fixed to the ends of the arms by means of an oscillating flange; its stems, of great length, are calculated to buckling with the own loads plus the windward windward component; and because said cylinders are attached to the chassis by means of a pin and ball that allows them to oscillate and align, this mechanism being the first axis of the zenith drive. 8. Large-area three-axis solar tracker, according to claims 1 to 7, characterized in that in the design of the chassis the supports of the carrier-grating grid are distributed, such that the weights on them coincide with the vertical component of the wind thrust at leeward at 40 m / s, to ensure that the grill will descend by its own weight when the wind approaches this value, having a passive safety against the wind, such that in the event of any anomalies type, the grill can lie down and protect itself by its own weight. 9. Three-axis solar tracker of large surface area, according to claims 1 to 8, characterized in that the collector carrier rows are oscillatingly fixed on the chassis, which can be photovoltaic thermal panels or parabolic trough concentrators. 10. Three-axis solar tracker of large surface area, according to claims 1 to 9, characterized in that the collectors are grouped in rows lying on longitudinal trusses that can oscillate up to about 30 °, with respect to a bolted support, located on the chassis, by the action of two hydraulic cylinders; and because the control of said oscillation is carried out by means of encoders or potentiometers, this being the second axis of zenith drive.