U.S. patent application number 12/810927 was filed with the patent office on 2011-07-14 for solar energy concentrator-collector device.
This patent application is currently assigned to TECNOLOGIA SOLAR CONCENTRADORA, SL. Invention is credited to Victor Martinez Moll, David Martinez Verdu, Andreu Moia Pol, Huascar Paz Bernales, Ramon Pujol Nadal, Carles Riba Romeva, Hans Schweiger.
Application Number | 20110168160 12/810927 |
Document ID | / |
Family ID | 40823800 |
Filed Date | 2011-07-14 |
United States Patent
Application |
20110168160 |
Kind Code |
A1 |
Martinez Moll; Victor ; et
al. |
July 14, 2011 |
SOLAR ENERGY CONCENTRATOR-COLLECTOR DEVICE
Abstract
The invention relates to a solar energy concentrator-collector
device including a stationary reflector-concentrator with
reflector-concentrator modules joined to a stationary structure
forming a matrix. Each reflector-concentrator module includes a
frame and at least one reflective surface portion configured to
reflect the sun's rays and concentrate them in a linear focus. The
stationary structure is formed by frames fixed to supporting
profiles. A mobile receiver includes a mobile structure supporting
receptor elements parallel to the linear foci. A tracking mechanism
is connected to several the supporting profiles and to the mobile
structure in order to support and move the mobile structure on the
stationary reflector-concentrator so that the receptor elements
follow a path of maximum confluence of the sun's rays reflected by
the reflective surfaces as the relative position of the sun
changes.
Inventors: |
Martinez Moll; Victor;
(Palma, ES) ; Pujol Nadal; Ramon; (Palma, ES)
; Paz Bernales; Huascar; (Palma, ES) ; Riba
Romeva; Carles; (Palma, ES) ; Martinez Verdu;
David; (Palma, ES) ; Moia Pol; Andreu; (Palma,
ES) ; Schweiger; Hans; (Palma, ES) |
Assignee: |
TECNOLOGIA SOLAR CONCENTRADORA,
SL
Palma
ES
|
Family ID: |
40823800 |
Appl. No.: |
12/810927 |
Filed: |
December 26, 2008 |
PCT Filed: |
December 26, 2008 |
PCT NO: |
PCT/ES2008/000801 |
371 Date: |
August 16, 2010 |
Current U.S.
Class: |
126/573 |
Current CPC
Class: |
F24S 23/74 20180501;
F24S 2020/23 20180501; F24S 30/425 20180501; F24S 25/632 20180501;
F24S 2025/023 20180501; F24S 2023/872 20180501; F24S 25/33
20180501; F24S 2030/136 20180501; Y02B 10/20 20130101; Y02E 10/40
20130101; F24S 23/70 20180501; Y02E 10/47 20130101; F24S 2025/6007
20180501 |
Class at
Publication: |
126/573 |
International
Class: |
F24J 2/38 20060101
F24J002/38; F24J 2/40 20060101 F24J002/40; F24J 2/46 20060101
F24J002/46 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 28, 2007 |
ES |
P200703464 |
Claims
1.-25. (canceled)
26. A solar energy concentrator-collector device, of the type
comprising: a stationary reflector-concentrator with a plurality of
elongated concave reflective surfaces, each configured to reflect
the sun's rays and concentrate them in a linear focus parallel to a
longitudinal direction, said reflective surfaces being arranged
parallel next to one another and joined to a stationary structure;
a mobile receiver with a plurality of elongated receptor elements
arranged parallel to the direction of said linear foci and joined
to a mobile structure; and a tracking mechanism connected to said
stationary structure and to said mobile structure in order to
support and move the mobile structure on said stationary
reflector-concentrator in a path so that said receptor elements
follow the maximum confluence of the sun's rays reflected by the
reflective surfaces as the relative position of the sun changes;
wherein: each reflective surface portion substantially has the
shape of a ruled surface having a parabola vertex, a parabola axis
and a parabola focus coinciding with said linear focus, and the
tracking mechanism is arranged in order to support and move the
mobile structure such that each of the receptor elements of the
mobile receiver describes a circular path which passes through said
parabola focus, and which has a center on said parabola axis, a
lower point in the lower intersection with the parabola axis, and a
diameter slightly greater than a distance between the parabola
focus and said parabola vertex.
27. The device according to claim 26, wherein a ratio of the
diameter with respect to said distance is within the range
1<D/FV.ltoreq.1.10.
28. The device according to claim 26, wherein the reflective
surface portion has two side edges, said parabola vertex is
centered between said side edges, and the ratio of a distance
between the side edges of each reflective surface portion with
respect to the diameter of the circular path is in the range of
1:0.9 to 1:2.0.
29. The device according to claim 26, wherein the stationary
reflector-concentrator includes a plurality of
reflector-concentrator modules arranged forming a matrix of
longitudinal and transverse rows, each of said
reflector-concentrator modules comprising a frame to which at least
one upper element carrying at least one reflective surface portion
is fixed, wherein the stationary structure is formed by said frames
of the reflector-concentrator modules and by a plurality of
supporting profiles, where the frames of the reflector-concentrator
modules of each row are fixed at opposite ends or sides to at least
two of said supporting profiles.
30. The device according to claim 29, wherein said tracking
mechanism comprises at least three base bodies fixed to at least
two of the supporting profiles, and each of said base bodies
rotationally supports at least one supporting shaft on which a
pivoting arm connected to the mobile structure for guiding the
movements of the mobile structure is assembled.
31. The device according to claim 29, wherein said upper element
carrying said reflective surface portion of each
reflector-concentrator module is precisely positioned in a
predetermined stable operative position in relation to the
corresponding frame and the frame of each reflector-concentrator
module comprises first module positioning configurations
cooperating with second module positioning configurations provided
in said supporting profiles in order to position each
reflector-concentrator module and with it the corresponding
reflective surface portion in a predetermined operative position in
relation to the supporting profiles.
32. The device according to claim 31, wherein the supporting
profiles comprise retaining members associated with said second
module positioning configurations and capable of immobilizing said
first module positioning configurations with respect to the second
module positioning configurations.
33. The device according to claim 32, wherein said retaining
members are capable of a quick action by elastic deformation.
34. The device according to claim 31, wherein each base body of the
tracking mechanism comprises first receiver positioning
configurations precisely positioned with respect to said supporting
shaft, and the corresponding supporting profiles, or auxiliary
parts fixed thereto, comprise second receiver positioning
configurations precisely positioned with respect to said second
module positioning configurations, said first receiver positioning
configurations cooperating with said second receiver positioning
configurations in order to position each base body in a
predetermined operative position in relation to the corresponding
supporting profile and thereby assuring a predetermined degree of
precision for said path of the mobile receiver in relation to said
stationary reflector-concentrator.
35. The device according to claim 34, wherein the supporting
profiles are arranged transverse to the direction of said linear
foci and the frames of the reflector-concentrator modules of each
transverse row are fixed at their opposite ends to two of said
supporting profiles.
36. The device according to claim 35, wherein the plurality of
supporting profiles comprises at least two first supporting
profiles and at least one second supporting profile, each arranged
between two adjacent transverse rows of reflector-concentrator
modules, where each of said first and second supporting profiles
has a pair of facing upright walls in which the corresponding
second module positioning configurations are provided.
37. The device according to claim 36, wherein each of said first
supporting profiles has a channel shape open at the top where said
pair of facing upright walls extend from side edges of a bottom
wall.
38. The device according to claim 36, wherein the plurality of
supporting profiles furthermore comprises two third supporting
profiles arranged next to the outer ends of each of the end
transverse rows of reflector-concentrator modules, where each of
said third supporting profiles has an upright wall in which the
corresponding second module positioning configurations are
formed.
39. The device according to claim 36, wherein each base body of the
tracking mechanism is a reducer gearbox the output shaft of which
is said supporting shaft and the input shaft of which is connected
by movement transmission means to the output shaft of a drive motor
assembled in the corresponding first supporting profile.
40. The device according to claim 39, wherein at least two of the
base bodies of the tracking mechanism are installed in one and the
same first supporting profile and their respective input shafts are
connected by respective movement transmission means to a single
drive shaft installed along the first supporting profile and
coupled to the output shaft of a single drive motor assembled in
the first supporting profile.
41. The device according to claim 40, wherein the supporting shaft
of each base body is parallel to the longitudinal direction and is
fixedly connected to a first end of a pivoting arm, which has a
second end connected by a hinge pin to a corresponding leg which
extends downwards from the mobile structure, the stationary
structure, said pivoting arms and the mobile structure functioning
like an articulated parallelogram for guiding the movement of all
the receptor elements of the mobile receiver in unison with respect
to their respective reflective surfaces along a circular path.
42. The device according to claim 41, wherein each pivoting arm has
a length between the supporting shaft and said hinge pin that is
equal to half of said diameter of the circular path, and the sum of
a first normal distance between said lower point of the circular
path and the supporting shaft and a second normal distance between
the hinge pin and a central line of the receptor element is equal
to said half of the diameter of the circular path.
43. The device according to claim 42, wherein the supporting shaft
of each base body is shifted downwards and/or towards a side with
respect to the center of any of the circular paths.
44. The device according to claim 26, wherein the mobile structure
comprises a plurality of longitudinal profiles and transverse
profiles connected to one another forming a grid, and said receptor
elements are supported at their ends between every two of said
transverse profiles.
45. The device according to claim 44, wherein each of said receptor
elements comprises at least one receptor tube for a heat-transfer
fluid, with an inlet end and an outlet end connected and
communicated with a circuit for said heat-transfer fluid.
46. The device according to claim 45, wherein at least one of said
transverse profiles of the mobile structure is a profile having a
closed cross-section forming a supply duct or a return duct of said
circuit for the heat-transfer fluid, and at least one of said inlet
and outlet ends of each receptor tube is connected and communicated
with a respective duct of said supply and return ducts formed by
the transverse profile.
47. The device according to claim 46, wherein the receptor tube of
each receptor element is bent such that its inlet and outlet ends
are at one and the same end of the receptor element, and the supply
and return ducts are formed by a single transverse profile of the
mobile structure or by two transverse profiles located next to one
another.
48. The device according to claim 29, wherein the at least one
upper element of each reflector-concentrator module is an arched
upper sheet of metal having a polished outer surface for forming
the at least one reflective surface portion.
49. The device according to claim 48, wherein each
reflector-concentrator module furthermore comprises a lower sheet
and a filler material arranged between the upper element and the
lower sheet, said filler material being adhered to the upper
element, to the lower sheet and to the frame.
50. The device according to claim 44, wherein each of the receptor
elements is rotationally supported at its ends such that it can
rotate about a longitudinal axis, and receptor elements are
connected by movement transmission means to a driving pulley
centered in the hinge pin and fixedly joined to the pivoting arm,
the transmission ratio being such that the rotational speed of the
receptor elements is half the rotational speed of the pivoting
arm.
51. The device according to claim 29, wherein the reflective
surface portions are located at a higher level with respect to
upper edges of said supporting profiles, and an automatic cleaning
device is configured and arranged for shifting cleaning elements
along the longitudinal direction of the reflective surfaces in
cooperation with a cleaning liquid.
Description
TECHNICAL FIELD
[0001] The present invention generally relates to a solar energy
concentrator-collector device and more specifically to a solar
energy concentrator-collector device comprising a stationary
reflector for reflecting and concentrating the sun's rays and a
mobile receiver moved by a tracking mechanism for following the
maximum confluence of the sun's rays reflected by the fixed
reflector as the relative position of the sun changes.
BACKGROUND OF THE INVENTION
[0002] Solar collectors configured to collect thermal or
photovoltaic energy from the sun's rays directly impinging on the
same are known. However, the energy efficiency of such collectors
is relatively low due to the low energy density of the impinging
rays. There are solar collectors of this type which use thermal
energy of the sun's rays to heat a heat-transfer fluid. However,
the heat-transfer fluid can only reach rather low temperatures
which do not allow the thermal energy to be transformed into
mechanical work.
[0003] Patent U.S. Pat. No. 3,868,823 discloses a
concentrator-collector device comprising reflective surfaces
suitable for reflecting substantially parallel impinging rays
towards respective linear foci which move in a predetermined path
in response to changes in the angle of the impinging rays, linear
receivers arranged for receiving the reflected rays, and tracking
mechanisms driven to move the receivers in coincidence with the
mentioned linear foci as the linear foci shift along said
predetermined path. Each reflective surface can be a continuous
concave surface or it can be formed by different planar segments.
In one application, the reflective surfaces are arranged to reflect
the sun's rays and the receiver includes a duct for conveying a
heat-transfer fluid which starts to boil because of the heating
effect of the sun's concentrated rays, such that the resulting
steam can be used to generate mechanical work.
[0004] Patent GB-A-1581253 describes a concentrator-collector
device similar to that of the mentioned patent U.S. Pat. No.
3,868,823, in which the reflective surfaces of the fixed reflector
are supported on a sandwich structure made up of an upper sheet of
metal, a lower sheet of metal and rigid insulating foam between
both. In one embodiment, the reflective surfaces are provided by a
polished outer surface of the upper sheet of metal. Several
sandwich structures are arranged next to one another and their side
edges are joined together in a tight manner for the purpose of
functioning like a roof of a building. Several linear receivers are
integrated in a mobile structure supported by a plurality of
pivoting supporting arms assembled on a fixed structure supporting
the reflector, such that the mobile structure, the pivoting
supporting arms and the fixed structure function like an
articulated parallelogram for guiding the movement of all the
receivers in unison with respect to their respective reflective
surfaces along a circular path selected for following the maximum
concentration of the sun's reflected rays. A tracking mechanism
driven by a motor is connected by means of a drive arm to the
mobile structure to move the mobile structure along a portion of
said circular path synchronously with the relative movement of the
sun.
[0005] For good efficiency, the relative positions between the
reflective surfaces and the receivers are critical for assuring
that the linear receivers coincide at all times with the areas of
maximum confluence of reflected rays. This involves achieving
precision in the positions of the reflective surfaces with respect
to one another and with respect to the fixed structure during the
installation of the fixed reflector, precision in the positions of
the linear receivers with respect to one another and with respect
to the mobile structure during the construction and installation of
the mobile structure, and precision in the positions of the shafts
on which the pivoting supporting arms guiding the movements of the
mobile structure in relation to the reflective surfaces rotate
during the installation of the mobile structure and of the
associated tracking mechanism in the fixed structure. Minor
accumulated tolerances or errors in the positioning of the
different elements can mean that the linear receivers are located
and move shifted away from the areas of maximum confluence of
reflected rays, and thereby the benefit of concentrating the sun's
rays is lost to a greater or lesser extent.
[0006] The mentioned patents U.S. Pat. No. 3,868,823 and
GB-A-1581253 neither describe nor suggest any specific device or
process for positioning the different elements of the
concentrator-collector device with respect to one another with
suitable precision. A classic process for installing a
concentrator-collector device of this type comprises fixing the
reflective surfaces on a fixed structure, building the mobile
structure including the linear receivers and installing the mobile
structure on the fixed structure by means of the pivoting arms and
the tracking mechanism, all using the measurement of distances,
levels, plumb bobs, etc. in situ, and performing cutting, drilling,
welding operations, etc. in situ. This classic process has been
shown to be rather inoperative due to the time consumed and the low
level of precision obtained.
[0007] Another aspect to be taken into account is how to determine
the path that a linear receiver must follow in order to follow the
maximum concentration of the sun's rays reflected by a reflective
surface in the form of a ruled parabolic or approximately parabolic
concave surface when the angle of incidence of the sun's rays
changes as the relative position of the sun changes. In fact, with
a reflective parallel ruled parabolic surface, the sun's reflected
rays are concentrated only in a linear focus, which coincides with
the focus of the parabola, when the sun's rays have normal
incidence, i.e., parallel to the axis of the parabola. When the
sun's rays impinge forming an angle with respect to the normal, the
maximum concentration of the rays is scattered in the area of a
triangle formed between the rays reflected from a first end edge,
from a second opposite end edge and from the center of the
reflector. The mentioned triangle increases its size as the angle
of incidence of the sun's rays moves away from the normal, i.e.,
the dispersion of the reflected rays is greater the more obliquely
the sun's rays impinge on the reflector. The growth rate of the
triangle reduces the greater the distance from the focus to the
vertex of the parabola in relation to the width between opposite
end edges of the reflector.
[0008] Patent JP-A-10026423 describes a solar energy
concentrator-collector device provided with a fixed concave
reflector and a mobile receiver connected to a tracking mechanism
capable of moving the mobile receiver along a path which follows
the locus of the centers of imaginary circles inscribed in the
mentioned triangles formed between the rays reflected from the
right end, from the left end and from the center of the reflector
as the angle of incidence of the sun's rays changes. There are
established limit angles of incidence to the right and the left of
the normal, for which the size of the triangle is maximum. The
receiver is cylindrical in shape and has a diameter equal to that
of the imaginary circle inscribed in the maximum sized triangle,
which assures that the receiver will collect all the rays reflected
by the reflector along its entire path.
[0009] A drawback of the approach used in the mentioned patent
JP-A-10026423 is that it does not take into account other factors
which would allow optimizing the performance of the device using a
smaller sized receiver, such as, for example, the fact that the
energy of the concentrated rays in the triangle is not uniform,
being higher in the proximities of the side of the triangle formed
by the rays reflected from the center of the reflector and lower in
the proximities of the opposite vertex.
DISCLOSURE OF THE INVENTION
[0010] Throughout this specification, the term "solar collector
device" is used to designate a device the function of which is to
transform solar radiation into thermal energy (thermal solar
collector device) or electric energy (photovoltaic solar collector
device), which can be made up of several sub-systems such as a
receiver, reflector, tracking mechanism. The term "receiver" is
used to designate a component of a solar collector in which the
transformation of the solar radiation into thermal or electric
energy takes place. The term "reflector-concentrator" is used to
designate a sub-system present in a solar collector the function of
which is to concentrate the solar radiation and direct it towards
the receiver using a high specular reflectance surface as a means
for concentrating the energy. This increases the efficiency of the
energetic transformation while at the same time the necessary
receiver surface is reduced. The term "linear focus" is used to
designate an area of the space where the radiation reflected by the
reflector-concentrator reaches its maximum density and which has an
elongated, substantially rectilinear shape. A linear focus is
produced by a reflective parallel ruled concave surface, for
example, a reflective surface with a parabolic or approximately
parabolic cross-section, several reflective surface sections, each
with a parabolic or approximately parabolic cross-section, or a
plurality of planar reflective surface sections arranged like a
Fresnel mirror. Thus, the linear focus, although in some
theoretical cases can have the shape of a geometric line, in
practice it takes up a certain elongated, approximately prismatic
volume in space (see, for example, patent JP-A-10026423). The term
"tracking mechanism" is used to designate a system which allows the
positioning of either the reflector-concentrator, the receiver, or
the assembly of both, according to the position of the sun, such
that the linear focus produced by the reflector-concentrator at all
times coincides with the position of the receiver.
[0011] The present invention contributes to mitigating drawbacks of
the prior art by providing a solar energy concentrator-collector
device built from modular elements prepared for being assembled or
fixed in situ using conventional fixing means, such as screwing
elements or the like, or retaining elements having quick action by
elastic deformation. The modular elements are provided with
respective positioning configurations suitable for being mutually
coupled during the assembling or fixing operations to provide
precise positioning of the different modular elements. This allows
the quick and easy installation of the device on a fixed supporting
structure, such as, for example, a roof of a building or a
structure made on purpose, with great precision in the relative
positions of its components in comparison with other devices of the
prior art.
[0012] To that end, the solar energy concentrator-collector device
of the present invention comprises a stationary
reflector-concentrator formed by a plurality of
reflector-concentrator modules arranged forming a matrix of
longitudinal and transverse rows, where each of said
reflector-concentrator modules comprises a frame to which at least
one upper element carrying at least one reflective surface portion
is fixed. Each reflective surface portion is concave and elongated
and is configured to reflect the sun's rays and concentrate them in
a linear focus parallel to a longitudinal direction thereof. In the
stationary reflector-concentrator, the reflective surface portions
are arranged aligned in the longitudinal rows forming, as a whole,
reflective parallel elongated concave surfaces next to one another.
The reflective surfaces are joined to a stationary structure formed
by a plurality of parallel supporting profiles and by the frames
themselves of the reflector-concentrator modules.
[0013] More specifically, the frames of the reflector-concentrator
modules of each row are fixed at opposite ends or sides to two of
said supporting profiles by means of conventional fixing means. The
solar energy concentrator-collector device furthermore comprises a
mobile receiver with a plurality of elongated mutually parallel
receptor elements arranged parallel to the direction of said linear
foci and joined to a mobile structure, and a tracking mechanism
connected to said stationary structure and to said mobile structure
in order to support and move the mobile structure on the reflective
surfaces of the stationary reflector-concentrator in a path so that
said receptor elements follow the maximum confluence of the sun's
rays reflected by the reflective surfaces as the relative position
of the sun changes.
[0014] The mentioned tracking mechanism comprises at least three
base bodies fixed to at least two of the supporting profiles by
means of conventional fixing means, and each of said base bodies
rotationally supports at least one supporting shaft on which a
pivoting arm linked to the mobile structure for guiding the
movements of the mobile structure is assembled.
[0015] Each base body of the tracking mechanism comprises first
receiver positioning configurations precisely positioned with
respect to said supporting shaft, and second receiver positioning
configurations precisely positioned with respect to said second
module positioning configurations are provided in the corresponding
supporting profiles, or in auxiliary parts fixed thereto. The
mentioned first receiver positioning configurations cooperate with
said second receiver positioning configurations in order to
position each base body in a predetermined operative position in
relation to the corresponding supporting profile and thereby
assuring a predetermined degree of precision for said path of the
mobile receiver in relation to said stationary
reflector-concentrator. In other words, a series of elements making
up the structure and the tracking mechanism of the solar energy
concentrator-collector device, which are connected to one another
by a chain of mutually coupled positioning configurations which
guarantee the correct positioning of the mobile receiver with
respect to the stationary reflector-concentrator, are arranged
between the collectors of the mobile receiver and the
reflector-concentrator modules of the stationary
reflector-concentrator.
[0016] The present invention furthermore provides an optimized path
for the receptor elements in relation to the reflecting elements.
The mentioned optimized path of the receptor element has been
obtained from an iterative theoretical calculation for different
shapes and proportions of the reflective surface portion and for
different ranges of incidence conditions of the sun's rays
simulating all the seasons of the year. The calculations have been
performed taking many factors into account, for example, the energy
of the concentrated rays in the mentioned triangle is higher in the
proximities of the side of the triangle formed by the rays
reflected from the center of the reflector than in the proximities
of the opposite vertex. It has thus been found that an optimal
reflective surface has substantially the shape of a ruled surface
having a substantially parabolic cross-section with two
longitudinal side edges, a parabola vertex, a parabola axis and a
linear focus coinciding with the parabola focus. Although it is not
absolute necessary, the two mentioned longitudinal side edges are
generally equidistant to said parabola vertex. With one such
reflective surface, an optimal circular path for a collecting
element passes through said parabola focus and has a center on said
parabola axis, a lower point in the lower intersection of the path
with the parabola axis, and a diameter slightly greater than a
distance between the parabola focus and said parabola vertex. For
example, an optimal value for the ratio of the diameter of the
circular path with respect to said distance from the parabola focus
to the parabola vertex is within the range 1<D/FV.ltoreq.1.10,
i.e., the diameter is greater than the distance from the parabola
focus to the parabola vertex but less than or equal to 1.10 times
the distance from the parabola focus to the parabola vertex. A
likewise significant parameter is the ratio of the width, i.e., the
distance between the side edges of the reflective surface, with
respect to the diameter of the circular path. It has been found
that an optimal value for this parameter is in the range of 1:0.9
to 1:2.0.
[0017] With this construction, the present invention provides a
solar energy concentrator-collector device which can be installed
in a relatively easy manner with a guarantee in the precision of
the relative positioning of its components and with an optimized
path for the receptor elements of the mobile receiver.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The previous and other features and advantages will be more
fully understood from the following detailed description of several
exemplary embodiments with reference to the attached drawings, in
which:
[0019] FIG. 1 is a perspective view of a solar energy
concentrator-collector device according to an embodiment of the
present invention;
[0020] FIG. 2 is a perspective view of a reflector-concentrator
module forming part of a stationary reflector-concentrator of the
concentrator-collector device of FIG. 1;
[0021] FIG. 3 is a partial perspective view of three different
types of supporting profiles forming part of a stationary structure
to which the stationary reflector-concentrator of FIG. 1 is
joined;
[0022] FIG. 4 is a partial exploded perspective view showing a
fixing device for joining the reflector-concentrator module of FIG.
2 to one of the supporting profiles of FIG. 3;
[0023] FIGS. 5 and 6 are partially sectioned partial views showing
the operation of the fixing device of FIG. 4;
[0024] FIG. 7 is a side elevational view of the solar energy
concentrator-collector device of FIG. 1;
[0025] FIG. 8 is a cross-section view taken along the plane
indicated VII-VII in FIG. 1;
[0026] FIG. 9 is a detailed elevational view showing a base body of
a tracking mechanism forming part of the solar energy
concentrator-collector device of FIG. 1;
[0027] FIG. 10 is a detailed cross-section view showing the fluid
connections of receptor elements forming part of a mobile receiver
of the solar energy concentrator-collector device of FIG. 1;
[0028] FIG. 11 is a schematic depiction of the path of the mobile
receiver with respect to the stationary reflector-concentrator
provided by the tracking mechanism; and
[0029] FIG. 12 is a partial elevational view of another embodiment
of the present invention including a mechanism for the orientation
of the receptor elements according to the changing position of the
mobile receiver.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0030] Referring first to FIG. 1, there is shown a solar energy
concentrator-collector device according to an embodiment of the
present invention, comprising a stationary reflector-concentrator 1
joined to a stationary structure 21, a mobile receiver 2 joined to
a mobile structure 3 and a tracking mechanism 4 connected to the
mentioned stationary structure 21 and mobile structure 3 in order
to support and move said mobile receiver 2 with respect to said
stationary reflector-concentrator 1.
[0031] The stationary reflector-concentrator 1 includes a plurality
of reflector-concentrator modules 5 (one of which is shown in FIG.
2) arranged forming a matrix of longitudinal and transverse rows
and connected to a plurality of parallel supporting profiles 13a,
13b, 13c for forming a stationary structure 21. As is best shown in
FIG. 2, each of said reflector-concentrator modules 5 comprises a
frame 6 to which an upper element 18 having a reflective surface is
fixed. In the embodiment shown, the upper element 18 is an upper
sheet of metal defining two reflective concave arched surface
portions 8 and side extensions 18a bent downwards. The reflective
surface portions 8 have a polished reflective outer surface. The
mentioned frame is formed, for example, by a pair of opposite end
plates 75 closing the reflector-concentrator module 5 at its two
longitudinal ends, connected to one another by internal
longitudinal connection members 76 (FIG. 5). The
reflector-concentrator module 5 furthermore comprises a lower sheet
20 with side extensions 20a bent upwards, and a filler material 77
(FIG. 5), such as, for example, expanded polyurethane, arranged
between the upper element 18, the lower sheet 20 and the end plates
75. Furthermore, the filler material 77 is adhered to the upper
element 18, to the lower sheet 20 and to the frame 6, said
longitudinal connection members 76 of the frame 6 being embedded in
the filler material 77. The filler material 77 is rigid enough to
precisely guarantee a predetermined stable operative position of
the upper element 18, and accordingly of the reflective surface
portions 8, in relation to the frame 6. Alternatively, the
reflector-concentrator module 5 could comprise one single
reflective surface portion 8, or more than two of them, and the
reflective surfaces could be provided by any number of additional
reflective elements joined to the upper element 18 instead of being
a polished surface thereof.
[0032] Each reflective surface portion 8 of the
reflector-concentrator module 5 substantially has the form of a
ruled concave surface, elongated, configured to reflect the sun's
rays and concentrate them in a linear focus parallel to a
longitudinal direction indicated by means of the arrow DL in the
figures. In the concentrator-collector device, the reflective
surface portions 8 of the reflector-concentrator modules 5 forming
longitudinal rows are aligned forming said elongated reflective
surfaces arranged parallel next to one another to concentrate the
sun's reflected rays in a plurality of respective elongated linear
foci. The mobile structure 3 of the mobile receiver 2 is formed by
a plurality of longitudinal profiles 33 and transverse profiles
34a, 34b connected to one another forming a grid in which a
plurality of elongated receptor elements 35 are installed forming
alignments arranged parallel to the direction of said linear foci
F. There is an alignment of receptor elements 35 for each alignment
of reflective surface portions 8 and accordingly for each linear
focus. The receptor elements 35 are supported at their ends between
every two of said transverse profiles 34a, 34b in the grid of the
mobile structure 3. The mentioned tracking mechanism 4 comprises
four base bodies 10 fixed to two of the supporting profiles 13a,
and each of said base bodies 10 rotationally supports a supporting
shaft 11 on which a pivoting arm 37 connected to the mobile
structure 3 for guiding the movements of the mobile structure 3 is
assembled. As will be explained in detail below, the tracking
mechanism 4 is motor-driven and controlled for moving the mobile
structure 3 above said stationary reflector-concentrator 1 in a
path so that the receptor elements 35 follow the maximum confluence
of the sun's rays reflected by the reflective surfaces as the
relative position of the sun changes. The number of base bodies 10
is not limited to four, although it will be understood that at
least three base bodies 10 fixed to at least two of the supporting
profiles 13a are necessary for supporting the mobile structure
3.
[0033] In the embodiment shown in FIG. 1, the supporting profiles
13a, 13b, 13c are arranged mutually parallel and transverse to the
direction of said linear foci F, i.e., transverse to the
longitudinal direction DL. The frames 6 of the
reflector-concentrator modules 5 of each transverse row are fixed
at their opposite ends to two of said supporting profiles 13a, 13b,
13c. To that end, the frame 6 of each reflector-concentrator module
5 comprises first module positioning configurations 9 (best shown
in FIG. 4) cooperating with second module positioning
configurations 14 provided in said supporting profiles 13a, 13b,
13c in order to position each reflector-concentrator module 5, and
accordingly the corresponding reflective surface portions 8, in a
predetermined operative position in relation to the supporting
profiles 13a, 13b, 13c.
[0034] FIG. 3 shows three different types of supporting profiles
13a, 13b, 13c which, together with the frames 6 of the
reflector-concentrator modules 5, form the stationary structure 21
of the concentrator-collector device. In the embodiment shown in
FIG. 1, the stationary structure 21 comprises two first supporting
profiles 13a and a second supporting profile 13b, each of which is
arranged between two adjacent transverse rows of
reflector-concentrator modules 5. Both the first supporting
profiles 13a and the second supporting profile 13b have the shape
of a channel open at the top defining a pair of facing upright
walls 40 in which the corresponding second module positioning
configurations 14 are provided. In the first supporting profiles
13a, the two facing upright walls 40 extend from side edges of a
bottom wall 41 and are significantly separated in order to allow
housing the base bodies 10 of the tracking mechanism 4 between the
same. In the second supporting profile 13b, the two upright walls
40 are much closer and leave just enough space between them to
allow fixing the reflector-concentrator modules 5. The stationary
structure 21 furthermore comprises two third supporting profiles
13c arranged next to the outer ends of each of the two transverse
rows of reflector-concentrator modules 5 located at the
longitudinal ends of the stationary structure 21. Each of said
third supporting profiles 13c has an angular shape with a single
upright wall 40 in which the corresponding second module
positioning configurations 14 are formed.
[0035] Alternatively, the stationary structure can comprise a
different number of supporting profiles, and/or the supporting
profiles can be configured differently from that shown, and/or can
be arranged parallel to the longitudinal direction DL or forming a
grid, with corresponding adaptations of the frames 6 of the
reflector-concentrator modules 5.
[0036] In relation to FIGS. 4 to 6 an embodiment of the first and
second module positioning configurations 9, 14 is now described.
The first module positioning configurations 9 are fixed in the
opposite end plates 75 of the frame 6 of the reflector-concentrator
module 5, each of which comprises a cylindrical portion 42 (FIG. 5)
tightly inserted through a hole 43 formed in the corresponding end
plate 75 and socket-coupled in the inner cavity of an end of a
tubular member of the frame 6. The first module positioning
configuration 9 has a widened outer portion 45 which is supported
against an outer surface of the end plate 16 around said hole 43,
and an axial hole through which a screw 46 is installed that serves
to fix the first module positioning configuration 9 to the frame 6
and optionally to join the end plates 75 to the internal
longitudinal connection members 76 of the frame 6. The first module
positioning configuration 9 comprises a groove 47 formed in an
outer portion thereof. The second module positioning configuration
14 formed in the upright wall 40 of the corresponding supporting
profile 13a, 13b, 13c is in the form of an L-shaped slot defining a
vertical portion 48 open at an upper edge of the upright wall 40
and a blind horizontal portion 49. The mentioned groove 47 of the
first module positioning configuration 9 is sized to be introduced
vertically downwards in said vertical portion 48 of the second
module positioning configuration 14 and then horizontally shifted
by said horizontal portion 49 until it abuts with the blind bottom
thereof, which determines the operative position of the
reflector-concentrator module 5 in relation to the corresponding
supporting profile 13a, 13b, 13c. In this operative position, a
head 50 of the second module positioning configuration 14 protrudes
from the opposite side of the upright wall 40.
[0037] The supporting profiles 13a, 13b, 13c furthermore comprise
retaining members 16 associated with said second module positioning
configurations 14 having the function of immobilizing the first
module positioning configurations 9 with respect to the second
module positioning configurations 14. In the embodiment shown, each
of said retaining members 16 comprises a plate made of a resistant
and slightly elastic material having a first end spaced from the
corresponding module positioning configuration 14 and a second
opposite end superimposed on the second module positioning
configuration 14. The mentioned first end of the retaining member
16 is fixed to the upright wall 40 of the supporting profile 13a,
13b, 13c, for example, by means of screws 51, and a hole 52 having
a diameter that is equivalent to the diameter of the head 50 of the
first module positioning configuration 9 is formed in the second
end. The mentioned hole 52 of the retaining member 16 is centered
with the position that the head 50 of the first module positioning
configuration 9 will adopt when it is in the operative position.
Thus, by elastically deforming the retaining member, for example,
with a finger, as is shown in FIG. 5, the first module positioning
configuration 9 of the reflector-concentrator module 5 can be
inserted in or extracted from the second module positioning
configuration 14.
[0038] However, when the head 50 of the first module positioning
configuration 9 is in the operative position in relation to the
second module positioning configuration 14 of the supporting
profile 13a, 13b, 13c, releasing the retaining member 16 causes an
elastic recovery thereof and the head 50 of the first module
positioning configuration 9 is trapped by the hole 52 of the
retaining member 16, such that the first module positioning
configuration 9 is immobilized with respect to the second module
positioning configuration 14, as is shown in FIG. 6. At least two
pairs of first and second module positioning configurations 9, 14
are obviously necessary for immobilizing the reflector-concentrator
module 5 with respect to each of the supporting profiles 13a, 13b,
13c. Thus, the coupling of the first and second module positioning
configurations 9, 14 and the action by elastic deformation of the
retaining members 16 can be performed in situ in a quick and easy
manner without needing to use tools and with a guarantee in the
correct operative position of the reflective surface portions 8 in
relation to the supporting profiles 13a, 13b, 13c of the stationary
structure 21. In the installed solar energy concentrator-collector
device, the supporting profiles 13a, 13b, 13c of the stationary
structure 21 will preferably rest on a planar surface or on
supporting elements defining a plane, which can be horizontal or
inclined. The solar energy concentrator-collector device of the
present invention is provided for being installed, for example, on
a roof or roofing of a building, although it can likewise be
installed in any other suitable location.
[0039] In relation to FIGS. 7 to 9, the installation and the
operation of the tracking mechanism 4 are now described. As
described above, in the embodiment shown the tracking mechanism 4
comprises four base bodies 10, two of them installed in each of the
two first supporting profiles 13a of the stationary structure 21.
Each base body 10 of the tracking mechanism 4 is a reducer gearbox,
including, for example, a worm gear, having an output shaft which
functions like the mentioned supporting shaft 11 and an input shaft
44 which is connected by movement transmission means to the output
shaft of a drive motor 32 assembled in the corresponding first
supporting profile 13a. Advantageously, the respective input shafts
44 of the two base bodies 10 which are installed in one and the
same first supporting profile 13a (FIG. 8) are connected by
respective movement transmission means to a common drive shaft 31
installed along the first supporting profile 13a and coupled to the
output shaft of a single drive motor 32 assembled in the first
supporting profile 13a.
[0040] In the embodiment shown, the base bodies 10 of the tracking
mechanism 4 are arranged such that their supporting shafts 11 are
parallel to the longitudinal direction. Each supporting shaft 11 is
fixedly connected to a first end of a pivoting arm 37, which has a
second end connected by means of a hinge pin 38 to a corresponding
leg 39 which extends downwards from the mobile structure 3. The
mentioned legs 39 are rigidly joined to the mobile structure 3,
whereby the stationary structure 21, the mentioned pivoting arms 37
and the mobile structure 3 function like an articulated
parallelogram for guiding the movement of all the receptor elements
35 of the mobile receiver 2 in unison with respect to their
respective reflective surfaces along a circular path T, which will
be described below in relation to FIG. 11.
[0041] The detail of FIG. 9 shows one of the base bodies 10 of the
tracking mechanism 4 connected to the corresponding first
supporting profile 13a by means of a pair of auxiliary parts 7. The
base body 10 comprises first receiver positioning configurations 12
precisely positioned with respect to said supporting shaft 11, for
example, in the form of circular projections formed in the wall of
the base body 10 around the supporting shaft 11. The mentioned
auxiliary parts 7 comprise second receiver positioning
configurations 15, for example in the form of holes in which the
first receiver positioning configurations 12 are tightly inserted.
In turn, respective facing holes through which positioning pins 53
are inserted are formed in the auxiliary parts 7 and in the upright
walls 40 of the first supporting profile 13a. Thus, the second
receiver positioning configurations 15 formed in the auxiliary
parts 7 are precisely positioned with respect to the second module
positioning configurations 14 formed in the supporting profile 13a.
The auxiliary parts 7 are fixed to the base body 10 and to the
upright walls 40 of the first supporting profile 13a by means of
respective screws 54, 55, for example, and the first receiver
positioning configurations 12 cooperate with the second receiver
positioning configurations 15 in order to position each base body
10 in a predetermined operative position in relation to the
corresponding supporting profile 13a and thereby assure a
predetermined degree of precision for the path of the mobile
receiver 2 in relation to said stationary reflector-concentrator 1
guided and driven by the tracking mechanism 4.
[0042] It will be understood that the positioning configurations
between the base body 10 and the first supporting profile 13a could
alternatively have shapes different to those shown, and that the
auxiliary parts 7 could be omitted or replaced with appendages of
the base body 10 and/or of the first supporting profile 13a without
departing from the scope of the present invention.
[0043] FIG. 9 also shows the movement transmission means between
the drive shaft 31, which is installed in bearing blocks 56 fixed
to the bottom wall 51 of the first supporting profile 13a, and the
input shaft 44 of the gear reducer of the base body 10. The
movement transmission means comprise a driving pulley 57 fixed to
the drive shaft 31, a driven pulley 58 fixed to the input shaft 44
and a belt 59 installed around the driving and driven pulleys 57,
58. In addition, a support 60 is fixed on the base body 10, on
which support 60 an angular position detector 61 associated with
the supporting shaft 11 is assembled. The angular position detector
61 can be used in an electronic control of the drive of the
tracking mechanism 4. Advantageously, the supporting bodies 10, the
components of the movement transmission means, the corresponding
drive motor 32 and other related accessories can be installed in
each first supporting profile 13a in a prior manufacturing phase
and supplied as an assembly to facilitate their quick installation
in situ.
[0044] An example of the construction of the mobile structure 3 is
described below in relation to FIG. 10. As has been mentioned
above, the mobile structure 3 supporting the mobile receiver 2 is
formed by a grid made up of longitudinal profiles 33 and transverse
profiles 34a, 34b, and the receptor elements 35 are supported at
their ends between every two of the transverse profiles 34a, 34b.
In the embodiment shown, the concentrator-collector device is aimed
at using thermal energy of the sun's rays to heat a heat-transfer
fluid, such as, for example, water. To that end, each of the
receptor elements 35 comprises a receptor tube 36 through which the
mentioned heat-transfer fluid circulates, with an inlet end 36a and
an outlet end 36b connected and communicated with a circuit for the
heat-transfer fluid. In the embodiment shown, each receptor element
comprises, as is conventional, a transparent tubular cover 62, for
example, of glass, inside which the mentioned receptor tube 36 is
arranged. The receptor tube 36 of each receptor element 35 is bent
such that it has inlet and outlet ends 36a, 36b protruding from one
and the same end of the transparent tubular cover 62 of the
receptor element 35. Several of the transverse profiles 34a of the
mobile structure 3 are sections having a closed cross-section
forming two parallel ducts which function, respectively, like a
supply duct 63a and a return duct 63b in connection with said
circuit for the heat-transfer fluid. The inlet and outlet ends 36a,
36b of each receptor tube 36 are connected and communicated
respectively with said supply and return ducts 63a, 63b formed by
one of the transverse profiles 34a.
[0045] Momentarily referring to FIG. 1, in the grid forming the
mobile structure 3 there are three merely structural transverse
profiles 34b supporting the blind ends of the receptor elements 35
and two transverse profiles 34a, intercalated between them, which
perform structural functions supporting the connection ends of the
receptor elements 35 while at the same time they provide the supply
and return ducts 63a, 63b to which the inlet and outlet ends 36a,
36b of the receptor tubes 36 of the receptor elements 35 are
connected and communicated. With this arrangement, each transverse
profile 34a forming the supply and return ducts 63a, 63b receives
the connection of receptor elements 35 from two opposite sides of
the same.
[0046] Returning to FIG. 10, an arrangement for the quick and easy
connection of the inlet and outlet ends 36a, 36b of the each
receptor tube 36 to the supply and return ducts 63a, 63b from
opposite sides of the transverse profile 34a is furthermore shown
therein. Each of the supply and return ducts 63a, 63b is traversed
by a connecting sleeve 64 passed through a pair of aligned holes
formed in facing walls of the transverse profile 34a and fixed to
the transverse profile 34a, for example, by means of a widened head
65 and a nut 66 coupled to a threaded outer portion thereof. The
mentioned connecting sleeve 64 is traversed from end to end by a
passage having an opening 67 in communication with the
corresponding supply or return duct 63a, 63b, and opposite ends of
said passage are sized to receive by socket-coupling corresponding
inlet or outlet ends 36a, 36b of the receptor tubes 36 of two of
the receptor elements 35 located in opposite sides of the
transverse profile 34a. Thus, the connecting sleeves function like
supporting members of the receptor elements 32 and like connections
for the flow of the heat-transfer fluid. At one of the ends of the
transverse profile 34a, the supply and return ducts 63a, 63b are
connected to the circuit of the heat-transfer fluid by means of
flexible tubes (not shown).
[0047] Alternatively, the inlet and outlet ends 36a, 36b of the
receptor tubes 36 can be connected to respective supply and return
ducts 63a, 63b formed in two different transverse profiles 34a
arranged next to one another. According to another alternative
embodiment, not shown, the receptor tube 36 of each receptor
element 35 is rectilinear and has the inlet and outlet ends 36a,
36b protruding from opposite ends of the transparent tubular cover
62, in which case the inlet and outlet ends 36a, 36b of each
receptor tube 36 will be connected to respective supply and return
ducts 63a, 63b formed in two different transverse profiles 34a
arranged next to opposite ends of the receptor element 35.
[0048] Now making reference to FIG. 11, each reflective surface
portion 8 of the reflector-concentrator module 5 defines a ruled
concave surface having a substantially parabolic cross-section. The
parabolic cross-section of the reflective surface portion 8 has two
side edges B1, B2, a parabola vertex V centered between said side
edges B1, B2, a parabola axis E and a parabola focus F coinciding
with the mentioned linear focus. The tracking mechanism 4 is
configured and arranged in order to support and move the mobile
structure 3 such that each of the receptor elements 35 of the
mobile receiver 2 describes a circular path T which passes through
said parabola focus F, and having a center C on said parabola axis
E, a lower point P in the lower intersection of the path T with the
parabola axis E, and a diameter D slightly greater than a distance
FV between the parabola focus F and the mentioned parabola vertex
V. The ratio of the mentioned diameter D of the circular path T
with respect to said distance FV between the parabola focus F and
the parabola vertex V is preferably within the range
1<D/FV.ltoreq.1.10. The mentioned side edges B1, B2 of the
reflective surface portion 8 are separated from one another by a
distance A, and the ratio of said distance A with respect to the
diameter D of the circular path T is preferably in the range of
1:0.9 to 1:2.0.
[0049] It will be observed from FIG. 11 that the center C of the
circular path T is at a significant height above the reflective
surface portion 8, which would be a drawback if positioning the
supporting shaft 11 of the base body 10 aligned with the center C
was desired because very high supports anchored in the first
transverse profile 13a and very long movement transmission means
for transmitting the movement from the drive shaft 31 to the input
shaft 44 of the base body 10 would be required. For this reason,
the supporting shaft 11 of each base body 10 is shifted downwards
and/or towards a side with respect to the center C of any of the
circular paths T, preferably close to one of the side edges B1, B2
of the reflective surface portion 8, or more specifically, close to
where the side edges B1, B2 of two adjacent reflective surface
portions 8 come together. The supporting shaft 11 of each base body
10 is fixedly connected to a pivoting arm 37 the distal end of
which is connected by means of a hinge pin 38 to a leg 39 which
extends downwards from the mobile structure 3. Each pivoting arm 37
has a length L between the supporting shaft 11 and said hinge pin
38, and said length L is equal to the radius of the circular path
T, or in other words, equal to half the diameter D of the circular
path T. In addition, the sum of a first normal distance d1 between
said lower point P of the circular path T and the supporting shaft
11 and a second normal distance d2 between the hinge pin 38 and a
central line L of the receptor element 35 is also equal to the
radius of the circular path T, or in other words, equal to the
other half of the diameter D of the circular path T. By fulfilling
these ratios, the circular path T will always be centered in the
center C no matter what the position of the supporting shaft 11. If
the supporting shaft 11 was located at a lower level than the lower
point P of the circular path T, the first normal distance d1 would
have a negative sign.
[0050] FIG. 12 shows another alternative embodiment of the solar
energy concentrator-collector device of the present invention, in
which the receptor elements 35 are, for example, photovoltaic
receivers having an essentially planar configuration, which are
more sensitive to the direction of the rays collected by the
thermal energy receptor elements. Here, each of the receptor
elements 35 is rotationally supported at its ends such that it can
rotate about a longitudinal axis 68, and several of the receptor
elements 35 are connected by movement transmission means to a
driving pulley 40 centered in the hinge pin 38 and fixedly joined
to the pivoting arm 37. In one of the transverse profiles 37b of
the mobile structure 3, which here are all merely structural
sections, a driven pulley 69 is assembled which can rotate with
respect to a shaft 70 parallel to the longitudinal shafts 68 and
located in one and the same plane as the same. An arm 71 integral
with the driven pulley 69 is hingedly connected to a transmission
rod 72, which in turn is hingedly connected with a series of arms
73 integral with the receptor element 35. A belt 74 or the like is
installed encircling arcs of the driving and driven pulleys 40, 69,
such that a rotation of the pivoting arm 37 around the supporting
shaft 11 is transmitted to the receptor elements 37 causing a
rotation thereof around their respective longitudinal shafts 68. A
transmission ratio between said driving pulley 40 and the receptor
elements 35 of 1:2, in which the receptor elements 35 rotate at
half the rotational speed of the pivoting arm 37, assures that the
receptor elements 35 adopt at all times a suitable position for
receiving the reflected rays at angles that are as close as
possible to the perpendicular. This construction can obviously be
applied to a concentrator-collector device using thermal energy
collecting elements associated with a circuit for a heat-transfer
fluid, for example such as those described above in relation to
FIGS. 1 to 10 or other similar ones.
[0051] According to another embodiment not shown, the
concentrator-collector device of the present invention comprises a
stationary reflector-concentrator 1 in which the reflective surface
portions 8 are located at a higher level with respect to upper
edges of the supporting profiles 13a, 13b, 13c, and the base bodies
10 are located in alignment with the confluence of two adjacent
reflective surface portions 8, such that there are substantially no
impediments along the longitudinal rows of aligned reflective
surface portions 8. The concentrator-collector device furthermore
comprises an automatic cleaning device based on a mechanism
configured and arranged for shifting cleaning elements, such as
brushes, cloths or the like, along the longitudinal direction of
the reflective surfaces in cooperation with a cleaning liquid
sprayed, for example, from strategically located nozzles connected
to a cleaning liquid circuit.
[0052] A person skilled in the art will be able to make
modifications and variations from the embodiments shown and
described without departing from the scope of the present invention
as it is defined in the attached claims.
* * * * *