U.S. patent application number 12/521047 was filed with the patent office on 2010-04-29 for biaxial solar tracker.
This patent application is currently assigned to SOLTEC ENERGIAS RENOVABLES, SL. Invention is credited to Thomas Grant, Raul MoralesTorres.
Application Number | 20100101559 12/521047 |
Document ID | / |
Family ID | 39491703 |
Filed Date | 2010-04-29 |
United States Patent
Application |
20100101559 |
Kind Code |
A1 |
Grant; Thomas ; et
al. |
April 29, 2010 |
BIAXIAL SOLAR TRACKER
Abstract
The invention includes a fixed platform bearing a circular rail,
supporting rolling elements to which is attached a mobile frame
with a sloping structure which holds a number of solar panels,
grouped in rows, the panels of each row being connected to
corresponding support shafts, supported on the sloping structure,
and a device for moving the frame and shafts in accordance with a
predetermined configuration. The frame includes a base with
attached thereto the rolling elements and the sloping structure is
raised above the base, at a distance from the fixed platform and
formed by two supporting beams that delimit an oblique plane and
are separated from each other by a distance greater than the
diameter of the rail.
Inventors: |
Grant; Thomas; (Molina de
Segura (Murcia), ES) ; MoralesTorres; Raul; (Molina
de Segura (Murcia), ES) |
Correspondence
Address: |
RATNERPRESTIA
P.O. BOX 980
VALLEY FORGE
PA
19482
US
|
Assignee: |
SOLTEC ENERGIAS RENOVABLES,
SL
Molina de Segura (Murcia)
ES
|
Family ID: |
39491703 |
Appl. No.: |
12/521047 |
Filed: |
December 4, 2007 |
PCT Filed: |
December 4, 2007 |
PCT NO: |
PCT/ES2007/000712 |
371 Date: |
January 5, 2010 |
Current U.S.
Class: |
126/600 |
Current CPC
Class: |
H02S 20/32 20141201;
F24S 30/452 20180501; F24S 2030/145 20180501; Y02E 10/50 20130101;
H02S 20/10 20141201; F24S 2030/136 20180501; Y02E 10/47
20130101 |
Class at
Publication: |
126/600 |
International
Class: |
F24J 2/38 20060101
F24J002/38 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 5, 2006 |
ES |
P200603109 |
Claims
1.-10. (canceled)
11. A biaxial solar tracker applicable to a photovoltaic solar
installation, of the type comprising a horizontal fixed platform,
bearing a circular track or rail; a rotatable frame provided with
rolling elements supported on said rail; a sloping structure with
fixed inclination, joined to said frame and having associated
thereto a plurality of solar panels, grouped in rows, the panels of
each row being connected to a corresponding support shaft which is
rotatable about itself or adapted to rotate with respect to another
parallel shaft, supported on said sloping structure, and first
means for rotating the mentioned frame and second means for
rotating the mentioned support shafts to orient at all times the
solar panels in accordance with a predetermined configuration,
wherein the frame comprises support columns and a base with
attached thereto said rolling elements, the sloping structure is
raised above, and seated on, said base through said support columns
spacing it from the mentioned fixed platform, and said sloping
structure is formed by at least two supporting beams that delimit
an oblique plane, said beams being separated from each other by a
distance greater than the diameter of the circular rail.
12. The solar tracker according to claim 11, wherein said frame
comprises a starting portion integrating several divergent columns
joined at points close to their free ends by transverse reinforcing
beams, an upper section which is enlarged with respect to the base,
encompassed by said free ends, defining a support for square parts
or brackets attached to said inclined supporting beams forming the
sloping structure.
13. The solar tracker according to claim 12, wherein said
supporting beams are inclined an angle substantially equal to the
minimum angle of inclination adoptable by each panel plus the mean
angle between said minimum angle of inclination and the maximum
angle of inclination adoptable by each panel, all of said angles
being taken with respect to the horizontal.
14. The solar tracker according to claim 13, wherein said
supporting beams are inclined an angle of substantially 45 degrees,
said minimum angle of inclination adoptable by each panel is of
substantially 10 degrees and said maximum angle of inclination
adoptable by each panel is of substantially 80 degrees, all of said
angles being taken with respect to the horizontal.
15. The solar tracker according to claim 13, wherein said
supporting beams are inclined an angle of substantially 50 degrees,
said minimum angle of inclination adoptable by each panel is of
substantially 10 degrees and said maximum angle of inclination
adoptable by each panel is of substantially 90 degrees, all of said
angles being taken with respect to the horizontal.
16. The solar tracker according to claim 13, wherein said support
shafts of each row of solar panels are transverse to said
supporting beams separated from each other by a sufficient distance
so that in none of the positions adoptable by each row of panels
does the perpendicular incidence of the sun on the panels of a row
cause a shadow on another row of panels, provided that said angle
of inclination of the panels is comprised between the minimum angle
and the maximum angle.
17. The solar tracker according to claim 11, wherein said second
means for moving the support shafts of the rows of solar panels
comprise a driving mechanism applied to a shaft and a transmission
mechanism formed by connecting rods and levers to transmit the
movement to the other shafts.
18. The solar tracker according to claim 17, wherein said driving
mechanism and said transmission mechanism are configured to rotate
said support shafts about themselves, each of said levers being
fixed at a first end to a respective one of said support shafts and
articulated at a second end with respect to the end of at least one
of said connecting rods.
19. The solar tracker according to claim 17, wherein said driving
mechanism and said transmission mechanism are configured to rotate
said support shafts with respect to said parallel shafts, each of
said levers being articulated at a first end to a respective one of
said parallel shafts, fixed at a portion at a distance from said
first end to a respective one of said support shafts and
articulated at a second end with respect to the end of at least one
of said connecting rods.
20. The solar tracker according to claim 11, wherein said support
shafts of the rows of solar panels project at their two ends beyond
said supporting beams.
Description
TECHNICAL FIELD
[0001] The present invention relates to the field of photovoltaic
solar installations intended for using solar energy by means of its
direct conversion into electric power, and more specifically it
relates to those installations based on active solar trackers,
i.e., on orientable dual-axis support structures, with controlled
movement very precisely synchronized with the position of the sun
in every moment and incorporating or grouping a plurality of
photovoltaic modules or panels. The support structure of the
tracker allows, by means of the coordinated movement of several of
its parts, tracking the route of the sun from when it rises in the
East to when it sets in the West, enabling the solar panels to
always be directly facing the sun.
PRIOR STATE OF THE ART
[0002] Different proposals are known in relation to solar trackers,
also known as solar orienting devices which, for the purpose of
achieving the maximum use of solar energy, consist of control
mechanisms and systems which allow orienting a series of solar
panels throughout the day such that the sun strikes them in a
substantially perpendicular manner.
[0003] Utility model ES-A-1050814 relates to one of said solar
trackers, which consists of a fixed platform defined by a circular
rail held by columns which raise it off the ground and keep it
leveled to allow a rotatable platform located above and provided
with wheels, to rotate so as to be oriented in azimuth. This
rotatable platform bears a plurality of solar panels arranged in
rows and columns on a sloping surface. In turn, each of the rows of
solar panels is rotatable about a shaft common to all of them, to
be oriented from a vertical position in which they receive the
solar rays at sunrise, until it reaches the most angled position at
midday when the sun is highest. Additionally, the azimuth rotation
of the mobile platform, simultaneous with that of the angling of
the panels, is performed by having coupled to the wheels a geared
motor, rotatable up to 210.degree., equivalent to fourteen hours of
the apparent solar path, from sunrise to sunset.
[0004] Utility model ES-A-1059027 proposes a rotatable base for
solar panel installations, formed by a U-shaped circular rail, on a
fixed platform or bed plate held by pillars leveling it according
to the orography of the area in which it is 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 sloping surface.
This inclined structure is attached and coupled to the fixed
circular rail by means of perpendicular bearings providing it with
angular mobility, as well as serving as a guide for the rotatable
movement.
[0005] Both the base of the sloping surface of ES-A-1050814, i.e.,
what is referred to therein as rotatable platform, and the
equivalent of ES-A-1059027, globally referred to as mobile inclined
structure, are directly rotatably coupled to the respective
circular rails, the diameter of said circular rails thus being
substantially equal to the distance between the two slopes, which
obliges design restrictions, especially with respect to span, which
are desirable to be overcome.
[0006] Otherwise, the inclinations of the support slopes of the
groups of solar panels of ES-A-1050814, and the distribution of the
rows of panels determine that in certain periods of insolation the
orientation of the panels causes a shadow on the neighboring panels
with a loss in the yield of the installation.
[0007] U.S. Pat. No. 5,191,875 relates to a solar boiler including
a solar panel pivotably coupled to a structure, which is rotatable
with respect to a base incorporating a rail on which wheels fixed
to the rotatable structure travel. The structure consists of a
series of support arms and cross-members providing it with certain
rigidity, but despite its configuration it also has the drawbacks
of the two mentioned documents, i.e., the base of the structure is
directly rotatably coupled to the respective circular rail, the
diameter of the circular rail being substantially equal to the
width of the structure and of the panel, which involves the
mentioned design restrictions with respect to span.
[0008] Additionally, there are proposals aimed at reducing the
angle of inclination of the sloping structure, for the purpose of
reducing the area of panels facing the horizontal wind, the total
height of the tracker, the overturning moment, all for the final
benefit of achieving a potential savings of material in the
structure due to the fact that the force of the wind would be less
on a structure with less angle of inclination. For example in the
previously mentioned utility models, said structure has an
inclination of 13.degree. in ES-A-1050814 and 28.degree. in
ES-A-1059027.
[0009] The possible benefit achieved by building a sloping
structure with a somewhat reduced inclination causes the drawback
of having to provide a greater distance between the rows of panels
to prevent the self-shadowing, which means that the length of the
sloping structure also has to be increased (because it is necessary
to increase the distance between rows), whereby the potential
savings of material in the structure, since it does not have to
withstand such strong forces of the wind as in structures with an
larger angle of inclination, may be offset by the amount of
additional material to be used due to the mentioned necessary
increase of the length of the structure.
[0010] With respect to the rotation of the solar panels about a
rotation shaft, there are different mechanisms responsible for
carrying out such task, some of which rotate all the shafts of all
the rows simultaneously, as is the case of the proposed mechanism
in utility model ES-A-1050814.
[0011] Utility model ES-A-1046171 describes a mechanism responsible
for pivoting a shaft of a number of solar panels, which mechanism
is formed by a towline guided by pulleys moving a semicircular part
coupled to said shaft.
[0012] It can be understood from the foregoing that the yield of a
photovoltaic installation is not only conditioned by the use of
efficient photovoltaic panels but that the support structure on
which the panels are placed can make a substantial difference and
allow reaching a more efficient yield.
DESCRIPTION OF THE INVENTION
[0013] The object of the present invention is to overcome the
drawbacks of conventional solar trackers described in the previous
section, providing a solar tracker with a more elaborate frame than
those formed by the conventional simple sloping structure, which
allows raising the mentioned sloping structure, and with it the
rows of panels borne by the same, as well as avoiding the mentioned
design restrictions, especially with respect to the span, enabling
the span of the sloping structure, with respect to its width, to
have greater dimensions than the diameter of the circular rail
which allows rotating the solar tracker, while at the same time
offering the solar tracker high robustness and resistance to the
wind.
[0014] Additionally, another object of the present invention is to
also provide a solar tracker the sloping structure of which has a
larger inclination than that of conventional trackers, for the
purpose of covering a smaller ground area, but which nevertheless
is designed such that it offers good wind resistance
characteristics.
[0015] To that end the present invention relates to a biaxial solar
tracker, applicable to a photovoltaic solar installation, of the
type comprising a horizontal fixed platform, bearing a circular
track or rail, rolling elements supported on said rail and to which
is attached a mobile frame including a sloping structure having
associated thereto a plurality of solar panels, grouped in rows,
the panels of each row being connected to corresponding support
shafts, supported on said sloping structure, and means for moving
the mentioned frame and the mentioned shafts to orient at all times
the solar panels in accordance with a predetermined
configuration.
[0016] As previously indicated, unlike conventional trackers in
which the frame is the actual sloping structure which seats on the
circular rail through the corresponding rolling elements, the frame
of the solar tracker proposed by the present invention
comprises:
[0017] a base with said rolling elements attached thereto, and
[0018] the sloping structure raised and seating on said base
through intermediate elements spacing it from the mentioned fixed
platform, and formed by two or more supporting beams, that delimit
an oblique plane, which are separated from each other by a distance
greater than the diameter of the circular rail.
[0019] The frame proposed by the invention allows, for a circular
rail of one and the same diameter, offering a much greater oblique
support plane for the rows of solar panels than that which is
offered by conventional trackers, and therefore providing a larger
solar capture surface than that of conventional trackers.
[0020] For a preferred embodiment the mentioned support shafts of
the rows of solar panels project at their two ends beyond said
supporting beams, whereby the total solar capture surface is even
much larger as it is not limited to the width of the sloping
structure, which in turn, as explained, is not limited to the
diameter of the circular rail either.
[0021] For the purpose of combining the adequate mentioned
characteristics of robustness and wind resistance, in the solar
tracker proposed by the invention the mentioned supporting beams
are inclined an angle substantially equal to the minimum angle of
inclination adoptable by each panel plus the mean angle between
said minimum angle of inclination and the maximum angle of
inclination adoptable by each panel, all of said angles being taken
with respect to the horizontal. By inclining the supporting beams
with this angle, the length thereof is optimized, i.e., the
shortest possible supporting beams are used without causing the
mentioned self-shadowing.
[0022] It should be pointed out that providing a raised sloping
structure, and hence a number of raised solar panels, allows
avoiding the negative effects that possible irregularities or
inclinations of the terrain in which the solar track is located may
cause by projecting unwanted shadows in the panels closest to the
ground.
[0023] For the purpose of designing and installing a photovoltaic
solar installation from a plurality of solar trackers like that
proposed by the present invention, solar trackers with respective
raised sloping structures at different heights, depending on the
location that each solar tracker is going to have, can be used to
avoid the mentioned unwanted shadows caused by the irregularities
or inclinations of the terrain, or by other adjacent solar
trackers, or by other elements of the photovoltaic
installation.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The previous and other advantages and features will be
better understood from the following detailed description of
several embodiments with reference to the attached drawings, which
must be given an illustrative and non-limiting interpretation, and
in which:
[0025] FIG. 1 is a rear perspective view of the solar tracker
proposed by the invention,
[0026] FIG. 2 is a side elevation view of the solar tracker of FIG.
1,
[0027] FIG. 3 is a side elevation sectioned view of part of the
solar tracker of FIG. 2, showing the mechanism rotating the rows of
solar panels about their rotation shafts, for one embodiment,
[0028] FIG. 4 is an enlarged cross-section of part of a rail,
inside which a rolling element of the proposed solar tracker
moves,
[0029] FIG. 5 is a side elevation view of part of the solar tracker
proposed by the present invention for an alternative embodiment to
that of FIG. 1,
[0030] FIG. 6 shows the elements of the solar tracker illustrated
in FIG. 5 plus the solar panels forming the different rows
thereof,
[0031] FIG. 7 is a front perspective view of the group of elements
of the solar tracker illustrated in FIG. 5, for the same
embodiment, and
[0032] FIG. 8 is a front perspective view of the same solar tracker
illustrated by FIG. 6.
DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS
[0033] The attached figures illustrate two embodiments of the solar
tracker proposed by the present invention, comprising a series of
common elements, whereas they also have some alternative elements
or configurations.
[0034] A first embodiment is illustrated in FIGS. 1 to 3, whereas a
second embodiment is illustrated in FIGS. 5 to 8.
[0035] Both embodiments show the main elements forming the solar
tracker proposed by the present invention which, as previously
described, is of the type comprising a horizontal fixed platform 1,
bearing a circular track or rail 2, rolling elements R (see FIG. 4)
supported on said rail 2 and to which is attached a mobile frame 4
including a sloping structure 5 having associated thereto a
plurality of solar panels P, grouped in rows H, the panels P of
each row H being connected to corresponding support shafts, four in
number E.sub.1-E.sub.4 for the first embodiment illustrated in
FIGS. 1 to 3 and three in number for the second embodiment
illustrated in FIGS. 5 to 8.
[0036] Each of said support shafts, E.sub.1-E.sub.4 or
E.sub.1-E.sub.3, is supported on said sloping structure 5, and the
solar tracker also comprises means for moving the mentioned frame 4
and the mentioned support shafts, E.sub.1-E.sub.4 or
E.sub.1-E.sub.3, to orient at all times the solar panels P in
accordance with a predetermined configuration.
[0037] In FIG. 4 (common for both embodiments) it can be seen how
one of the rolling elements R is introduced in the circular rail 2,
and supported by a plate 3, which is in turn fixed to the base B of
the mobile frame 4.
[0038] The frame 4 comprises a base B with said rolling elements R
attached thereto and the sloping structure 5 is raised above said
base B, at a distance from the mentioned fixed platform 1 and
formed by two supporting beams 6, 7 that delimit an oblique plane
and are separated from each other by a distance which, as can be
seen in FIG. 1, is greater than the diameter of the circular rail
2.
[0039] As discussed in a previous section, in the solar tracker
proposed by the invention the mentioned supporting beams 6, 7 are
inclined an angle substantially equal to the minimum angle of
inclination adoptable by each panel P plus the mean angle between
said minimum angle of inclination and the maximum angle of
inclination adoptable by each panel P, all of said angles being
taken with respect to the horizontal, i.e., the angle of
inclination of the beams 6, 7 is equal to:
Min . angle inclination of P + ( min . angle inclination of P + max
. angle inclination of P ) 2 ##EQU00001##
[0040] Said angles of inclination of the panels P are made
possible, for the embodiment illustrated in FIGS. 1 to 3, since
each row H of panels P pivots with respect to its respective
support shaft E.sub.1-E.sub.4.
[0041] For both illustrated embodiments (see FIGS. 2, 3, 5 and 6)
the supporting beams 6, 7 are inclined an angle of substantially 45
degrees, which is suitable for a minimum angle of inclination
adoptable by each panel P of substantially 10 degrees and a maximum
angle of inclination adoptable by each panel P of substantially 80
degrees.
[0042] For another embodiment, not illustrated, for which the
panels P can be inclined between 10 and 90 degrees, the supporting
beams 6, 7 are inclined an angle of substantially 50 degrees.
[0043] Said inclination of the beams 6, 7, i.e., of the sloping
structure 5, combined with the fact that the support shafts,
E.sub.1-E.sub.4 or E.sub.1-E.sub.3, of each row H of solar panels P
are transverse to said supporting beams 6, 7 separated from each
other by a sufficient distance, prevents the perpendicular
incidence of the sun on the panels P of a row H from causing a
shadow on another row of panels P in any of the positions adoptable
by each row H of panels P, provided that said angle of inclination
of the panels P is comprised between the minimum angle and the
maximum angle which, for the illustrated embodiment, has been
considered to be of 10 and 80 degrees, respectively.
[0044] For the illustrated embodiments, it can be seen, especially
in FIGS. 1 and 7, that the frame 4 comprises a starting portion
integrating several divergent columns 8 (which in FIGS. 1 and 7 are
four in number) joined at points close to their free ends 8a by
transverse reinforcing beams 9 given them consistency.
[0045] The upper section or plane enlarged with respect to the base
B, encompassed by said free ends 8a, defines a support for square
parts or brackets 10 attached to said supporting beams 6, 7 forming
the sloping structure 5, which thus seats on the base B through
what is generally referred to in a previous section as intermediate
elements which, for the described and illustrated embodiment, are
formed by the mentioned divergent columns 8, attached in turn by
the mentioned reinforcing beams 9.
[0046] In FIG. 7 it is seen how the solar tracker therein
illustrated has four of the mentioned reinforcing beams 9, although
said number can be different for other embodiments not
illustrated.
[0047] As previously mentioned, the span of the proposed solar
tracker is not limited, in terms of width, to the distance between
the supporting beams 6, 7, but rather, as seen in FIGS. 1 and 8,
for several preferred embodiments, the support shafts,
E.sub.1-E.sub.4 or E.sub.1-E.sub.3, of the rows H of solar panels P
project at their two ends beyond said supporting beams 6, 7, thus
providing a solar capture surface of a much greater width than the
diameter of the circular rail 2.
[0048] FIG. 7 illustrates a solar tracker with three support shafts
E.sub.1-E.sub.3 and FIG. 1 illustrates one with four support shafts
E.sub.1-E.sub.4, as a depiction of two preferred embodiments, since
the solar tracker proposed by the invention preferably has between
three and five support shafts, with a minimum angle of inclination
of the panels P of 10.degree., a maximum angle of elevation of the
panels P of 80.degree., the assembly of panels P is between two and
four times wider than it is high, and the angle of inclination of
the sloping structure 5 is of 45.degree..
[0049] For the embodiments illustrated, the mentioned means for
moving the support shafts, E.sub.1-E.sub.4, E.sub.1-E.sub.3, of the
rows H of solar panels P comprise a driving mechanism 11 (seen in
detail in FIG. 3) applied, unlike the proposal in utility model
ES-A-1050814, to a single shaft E.sub.3 and a transmission
mechanism formed by connecting rods 12 and levers 13 to transmit
the movement to the other shafts (E.sub.1, E.sub.2, E.sub.4 for the
first embodiment and E.sub.1, E.sub.2 for the second
embodiment).
[0050] The driving mechanism 11 also comprises, like in utility
model ES-A-1046171, a semicircular part 14 adjoined to a panel P,
but instead of using a towline moved along pulleys, it uses a chain
15 moved by a corresponding motor over gears or gear wheels 16.
[0051] For the mentioned first embodiment, illustrated in FIGS. 1
to 3, the support shafts E.sub.1-E.sub.4 act as rotation shafts of
the panels P, the mentioned driving mechanism 11 and said
transmission mechanism being configured to rotate the support
shafts E.sub.1-E.sub.4, in this case of rotation, about themselves,
for which purpose, as can be seen in FIG. 3, each of said levers 13
is fixed at a first end to a respective one of said support shafts
E.sub.1-E.sub.4 and articulated at a second end with respect to the
end of one or more of said connecting rods 12 (the levers 13 of the
end rows H each articulated to only one connecting rod 12, and the
levers 13 of the intermediate rows H each articulated to two
connecting rods 12).
[0052] As an alternative to what is described in the preceding
paragraph, for the mentioned second embodiment, illustrated in
FIGS. 5 to 8, the support shafts E.sub.1-E.sub.3 are not rotation
shafts, but rather they are adapted to rotate with respect to
parallel shafts G.sub.1-G.sub.3, the mentioned driving mechanism 11
and the mentioned transmission mechanism being configured to rotate
the support shafts E.sub.1-E.sub.3 with respect to said parallel
shafts G.sub.1-G.sub.3, for which purpose, as can be seen in FIGS.
5-7, each of said levers 13 is articulated at a first end to a
respective one of said parallel shafts G.sub.1-G.sub.3, fixed at a
portion at a distance from said first end to a respective one of
said support shafts E.sub.1-E.sub.3 and articulated at a second end
with respect to the end of one or more of said connecting rods
12.
[0053] The purpose of the configuration of a transmission mechanism
such as the one described in the preceding paragraph for the second
embodiment, i.e., the one that allows the rows H of solar panels P
to not rotate about their respective support shaft E.sub.1-E.sub.3
(as is the case of the first embodiment illustrated in FIGS. 1 to
3), but rather with respect to a distanced or remote parallel shaft
G.sub.1-G.sub.3, is to achieve that, in the event that a mechanical
element of said transmission mechanism breaks, the rows H of solar
panels P are positioned horizontally by gravity, pivoting with
respect to their respective parallel or remote shaft
G.sub.1-G.sub.3, in order to offer minimal wind resistance, i.e.,
it is possible for the rows H to offer a position of stable
equilibrium in the horizontal position.
[0054] In FIG. 7 it can be seen how the transmission mechanism
described is arranged only on the supporting beam 6, although for
other embodiments the possibility of arranging at least another
similar transmission mechanism in the other supporting beam 7 is
contemplated.
[0055] A person skilled in the art may introduce changes and
modifications in the embodiments described without departing from
the scope of the invention as it is defined in the attached
claims.
* * * * *