U.S. patent application number 12/756645 was filed with the patent office on 2010-10-07 for tracking unit for a solar collector.
Invention is credited to Klaus Hofbeck, Michael Killerman, Alexander Kist, Hans Poisel, Harry Schilling, Sebastian Schutz.
Application Number | 20100252026 12/756645 |
Document ID | / |
Family ID | 42675138 |
Filed Date | 2010-10-07 |
United States Patent
Application |
20100252026 |
Kind Code |
A1 |
Schilling; Harry ; et
al. |
October 7, 2010 |
Tracking Unit For A Solar Collector
Abstract
A tracking unit for solar collectors has at least two panels,
which can each be pivoted about a longitudinal axis. The axes are
arranged on a rotable frame on one plane. The position of each axis
within the individual panels is offset by a offset .DELTA.x in
relation to the adjacent panels. The individual panels are moved by
means of a lifting mechanism that pivots each of the panels about
the same angle. This arrangement significantly reduces mutual
shading and increases efficiency by about 10%.
Inventors: |
Schilling; Harry;
(Eichstatt, DE) ; Hofbeck; Klaus; (Neumarkt,
DE) ; Kist; Alexander; (Rothenbach, DE) ;
Killerman; Michael; (Nurnberg, DE) ; Schutz;
Sebastian; (Nurnberg, DE) ; Poisel; Hans;
(Leinburg, DE) |
Correspondence
Address: |
QUARLES & BRADY LLP
411 E. WISCONSIN AVENUE, SUITE 2040
MILWAUKEE
WI
53202-4497
US
|
Family ID: |
42675138 |
Appl. No.: |
12/756645 |
Filed: |
April 8, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/DE2010/075023 |
Mar 9, 2010 |
|
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|
12756645 |
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Current U.S.
Class: |
126/601 |
Current CPC
Class: |
F24S 2030/136 20180501;
F24S 2030/11 20180501; F24S 30/425 20180501; Y02E 10/47 20130101;
F24S 30/452 20180501; F24S 40/85 20180501; Y02B 10/20 20130101 |
Class at
Publication: |
126/601 |
International
Class: |
F24J 2/38 20060101
F24J002/38 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 12, 2009 |
DE |
102009012505.1 |
Sep 25, 2009 |
DE |
102009045033.5 |
Claims
1. Tracking unit for a solar collector comprising at least one
frame with at least two panels which can each be pivoted about a
pivoting axis, with the positions of the pivoting axes of adjacent
panels being displaced by a distance .DELTA.x in relation to a
central axis of the panels.
2. Tracking unit according to claim 1, wherein the pivoting axes of
the panels are arranged on the frame in one plane.
3. Tracking unit according to claim 1, wherein a plurality of
panels can be pivoted at the same angle by means of a mechanical
drive.
4. Tracking unit according to claim 1, wherein the frame is mounted
rotatably on a guide ring mounted rigidly on a mounting
surface.
5. Tracking unit according to claim 4, wherein the guide ring is
provided with a first bearing surface and an internal bearing
surface which is arranged at an angle of less than 90.degree. with
respect to the first bearing surface.
6. Tracking unit according to claim 5, wherein a first roller runs
on the first bearing surface and an internal roller runs on the
internal bearing surface, which are braced against each other.
7. Tracking unit according to claim 1, wherein a device for passive
fine adjustment of at least one light collector arranged on one
panel is provided, and the device is configured for alignment of at
least one light collector to the sun by means of thermal expansion
of a material that expands in response to heat.
Description
PRIORITY CLAIM
[0001] This application is a continuation of pending International
Application No. PCT/DE2010/075023 filed on Mar. 9, 2010, which
designates the United States and claims priority pending German
Applications No. 102009012505.1, filed Mar. 12, 2009 and
102009045033.5 filed Sep. 25, 2009.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates to a tracking unit for a solar
collector, in particular for harvesting sunlight, which can track
the current position of the sun. This allows the angle of incidence
of the rays to be perpendicular to the surface of the collector at
all times, thus achieving maximum efficiency of the collector.
[0004] 2. Description of Relevant Art
[0005] U.S. Pat. No. 4,798,444 discloses a solar collector which
receives solar radiation from different directions and therefore
does not require tracking.
[0006] U.S. Pat. No. 5,581,447 discloses a solar collector having a
movable biaxial lens system which feeds sunlight into a bundle of
optical fibers.
[0007] Another biaxial lens system for injecting light into a
bundle of optical fibers is disclosed in U.S. Pat. No. 4,589,400.
In this case, a collector head with light collecting elements
arranged on a surface tracks the sun biaxially.
[0008] The disadvantage of this tracking system is that the whole
collector surface has to be rotated and/or pivoted. This requires a
relatively large structure and a large area for moving the
collector head accordingly. Furthermore, large wind loads can occur
due to the large surface, which must also be arranged at a great
distance from the mounting plane to allow its movement.
SUMMARY OF THE INVENTION
[0009] The embodiments are based on the object of designing a
tracking unit for solar collectors, in particular for collectors
which feed the sun's rays into bundles of optical fibers, such that
it requires less space, has a lower wind load and can be mounted
closer to the installation surface. Furthermore, it is designed to
track the sun in a more precise manner.
[0010] In an embodiment the tracking unit has at least two panels
which are arranged on a frame and can each be pivoted on a
longitudinal axis. The position of the axes of rotation of the
individual panels is offset in relation to the adjacent panels by a
specified dimension .DELTA.x in each case. The movement of the
individual panels is achieved by means of a lifting mechanism or a
parallel drive, with which the panels can each be pivoted about the
same angle. Preferably, the panels have a rectangular, elongated
shape, with the longitudinal axis preferably running parallel to
the longer edge of the rectangle.
[0011] In a further embodiment the frame can be mounted rotatably
together with the panels in order to allow tracking along a second
axis.
[0012] In another embodiment the frame attached to a guide ring to
make it rotatable in a simple manner. This guide ring is provided
with a first bearing surface parallel to the frame and/or to the
panel arrangement. Furthermore, provision is made for an internal
bearing surface arranged at an angle of less than 90.degree. to the
first bearing surface.
[0013] According to a further embodiment a passive micro-adjustment
system for the position of the lenses is provided.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] In the following, the invention will be described by way of
example, without limitation of the general inventive concept, on
examples of embodiment and with reference to the drawings.
[0015] FIG. 1 shows a tracking unit.
[0016] FIG. 2 shows a lateral view of the tracking unit with
vertical panels.
[0017] FIG. 3 shows the tracking unit with panels pivoted on an
angle to the left.
[0018] FIG. 4 shows the panels pivoted to a high degree.
[0019] FIG. 5 schematically shows the positional and angular
relationships of the tracking unit.
[0020] FIG. 6 shows the positional and angular relationships with
pivoting to the left.
[0021] FIG. 7 shows the positional and angular relationships with
pivoting to the right.
[0022] FIG. 8 shows the positional and angular relationships for a
tracking unit without axial displacement
[0023] FIG. 9 shows a cross-section through the guide ring
including the guide rollers running on it.
[0024] FIG. 10 shows a thermally controlled tracking unit for the
lenses.
[0025] FIG. 11 shows a thermally controlled tracking unit for the
lenses in a balanced state.
[0026] FIG. 12 shows a thermally controlled tracking unit for the
lenses in details.
[0027] While the invention is susceptible to various modifications
and alternative forms, specific embodiments thereof are shown by
way of example in the drawings and will herein be described in
detail. It should be understood, however, that the drawings and
detailed description thereto are not intended to limit the
invention to the particular form disclosed, but on the contrary,
the intention is to cover all modifications, equivalents and
alternatives falling within the spirit and scope of the present
invention as defined by the appended claims.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0028] FIG. 1 shows a tracking unit. The solar collector includes
individual panels 20a, 20b, 20c, 20d, 20e. These panels are
pivoting mounted in a frame 10. The frame itself is rotatably
mounted on the guide ring 11 and can be rotated by means of a drive
system 12. The guide ring 11 is mounted rigidly on a mounting
surface, such as for instance on the roof of a house, a flat roof
or a wall. The individual panels 20a to 20e include a plurality of
lenses and/or light collectors 30 bundling solar radiation into
individual light guiding fibers. An optional solar sensor is
mounted rigidly onto the surface of a panel and is moved together
with this. It serves to detect the exact position of the sun and
therefore to reposition the panels precisely. Provision can also be
made for optional solar cells 13 for obtaining electrical energy,
for example for driving the tracking system.
[0029] In general a tracking unit for solar collectors has at least
two panels 20a, 20b, 20c, 20d, 20e, which are arranged on a frame
10 and can each be pivoted on a longitudinal axis. The positions of
the axes of rotation 21a, 21b, 21c, 21d, 21e of the individual
panels are displaced in relation to the adjacent panels by a
specified dimension .DELTA.x in each case. The movement of the
individual panels is achieved by means of a lifting mechanism or a
parallel drive, with which the panels can each be pivoted about the
same angle. Preferably, the panels have a rectangular, elongated
shape, with the longitudinal axis preferably running parallel to
the longer edge of the rectangle.
[0030] Such an arrangement results in the entire surface of the
solar collector being distributed across several sub-areas,
corresponding to the number of panels. This means that it is no
longer necessary for the whole surface to track the position of the
sun. In fact, only the individual sub-areas need to be moved. This
allows the entire configuration to be mounted considerably closer
to the installation surface, such as a roof or a wall. Accordingly,
the whole arrangement does not project as much, the appearance of
the building or other property is compromised less and the wind
load is reduced. Such an arrangement, which is relatively flat, can
now be mounted in large numbers without any problem on buildings,
building roofs or facades, often without the need for additional
building permits.
[0031] In order to allow tracking along a second axis, the frame 10
can be mounted rotatably together with the panels. This means that
the arrangement is largely free of the constraints of a mounting
angle relative to the mounting surface. It is understood that the
tracking unit also works without the frame being mounted
rotably.
[0032] In order to make the frame rotatable in a simple manner, it
is preferably attached to a guide ring. This guide ring is provided
with a first bearing surface parallel to the frame and/or to the
panel arrangement. Furthermore, provision is made for an internal
bearing surface arranged at an angle of less than 90.degree. to the
first bearing surface. This slanted arrangement means that this
internal bearing surface can also bear a (smaller) force
perpendicular to the first bearing surface as well as a force
arising at a right angle to this. This means that the frame with
the panels can be rigidly mounted to the guide ring.
[0033] FIG. 2 shows a schematic lateral view of the tracking unit.
The individual panels 20a to 20e can be seen from the side. These
are pivoting mounted on pivoting axes (also referred as rotary
axes) 21a to 21e. As can clearly be seen here, the rotary axes are
arranged at different positions relative to the individual panels.
The precise arrangement will be shown later in the FIGS. 5 to
8.
[0034] FIG. 3 shows tracking unit corresponding with FIG. 2,
whereby the panels are pivoted at a slight angle to the left. It
can clearly be seen that there has been a shift in the height of
the individual panels as a result of the different arrangements of
the rotary axes.
[0035] FIG. 4 shows an approximately 90.degree. rotation of the
panels relative to the horizontal. This also produces the maximum
offset in height relative to the horizontal. It is obvious that
this height offset reduces the mutual shadowing effect of the
individual panels. This means that more light can be collected.
[0036] FIG. 5 shows the size and angular relationships for a solar
tracking unit. The individual panels 20a to 20e are mounted by
means of the rotary axes 21a to 21e. The central axes of the panels
22a to 22e point vertically upward when the panels are arranged
horizontally. It is preferable for the distances 24a to 24d of the
central axes of the individual panels to be the same size and
determined by the size and/or width of the panels. These central
distances correspond to the distance of the individual panels less
the dimension .DELTA.x. In the example of the embodiment shown
here, the central axis 22c only runs through the rotational axis
21c in the case of the centre panel 20c. In the case of a panel
20d, the central axis 22d runs at a distance 23d from the rotary
axis 21d corresponding to .DELTA.x. This distance 23e corresponds
to 2 * .DELTA.x for the panel 20e. The same applies for the panels
20b and 20a, where in these cases the distances between the central
axes and the rotary axes are also .DELTA.x (for 20b) and 2 *
.DELTA.x (for 20a) respectively.
[0037] Generally, the distance or displacement between the central
axis and a rotary axis of the adjacent panel differs by
.DELTA.x.
[0038] The complete frame 10 can be designed to be smaller than an
embodiment where the central axes run through the rotary axes as
shown in FIG. 8, due to the fact that the rotary axes for the outer
panels 20a and 20e are attached on the inner sides. In addition,
the panels pivot inward toward the frame 10 so that the distance to
the adjacent arrangements can be kept smaller.
[0039] FIG. 6 shows the previous arrangement with the panels
pivoted at an angle 26. In this case, the central axes 22a to 22e
of the individual panels are pivoted by the angle 26 relative to
the horizontal.
[0040] FIG. 7 shows a tracking unit corresponding to the previous
figure, but where the individual panels are pivoted in the opposite
direction.
[0041] FIG. 8 shows a tracking unit where the central axes run
through the rotary axes. This produces constant distances 27 for
the individual rotary axes. These distances between the rotary axes
are greater than the distances between the rotary axes in an
arrangement according to FIG. 5. As a result, the frame 10 must be
designed to be larger.
[0042] FIG. 9 shows another cross-section through the guide ring
11. In this case, a first roller runs on the first bearing surface
41, which is visible. A second internal bearing surface 42, which
forms an angle less than 90.degree. with the first bearing surface
41, serves as a bearing surface for the internal roller 44. The two
rollers constitute a roller set and orbit the rotational axis of
the entire arrangement 45. The rollers can be rotated around their
central axes (shown by the dotted line) and are connected to the
frame 10 (not shown here). At least three such roller sets, each
consisting of a first roller and a second roller, are borne by the
frame 10 on the guide ring 11. As the two bearing surfaces 41 and
42 form an angle that is less than 90.degree., the internal roller
44 is able to exert a lesser vertical force component in the
direction of the first roller 43. The two rollers can be set to be
interlocking. This prevents the complete arrangement from slipping
upward out of the guide ring. This means that an arrangement of
this kind can also be mounted on sloping or vertical wall surfaces.
In the case of a vertical wall surface, the first bearing surface
41 would then be parallel to the vertical wall surface and would
also be positioned vertically.
[0043] FIG. 10 shows a thermally controlled tracking apparatus for
lenses and/or light collectors 30. The beams of sunlight 50 can
only be fed into the light collectors 30 with optimum efficiency
when the angle of incidence of the beams of sunlight 50 is parallel
to the principle orientation of the lens 32. In order to passively
minimise the angle 51 of misalignment, sunlight 50 is transmitted
via collimators 53a, 53b onto thermally expanding material 52a,
52b. Corresponding to the heat absorbed by this material, this
material expands and changes its thickness, as shown in the
drawing, so that the tracking plate 55 bearing the individual
lenses 30 is pivoted with respect to the base plate 54. In the
example of the misalignment shown here, more light strikes the
thermally expanding material 52b than the thermally expanding
material 52a. Accordingly, the material 52b will expand more.
[0044] Generally, if there is an angle of misalignment 51 between
this principal orientation 32 of the lens and/or the light
collector 30 and the beams of sunlight 50, this must be corrected
in order to maintain the optimal degree of efficiency. The exact
positioning of the individual lenses in the direction of the sun
requires a high level of technical complexity and in particular
small tolerances in terms of the mechanics of the individual panels
and their suspension. In order to minimise the complexity as much
as possible, a further embodiment provides for a passive
micro-adjustment system for the position of the lenses. To achieve
this, radiation from the sun is gathered and expandable material is
heated when subjected to the radiation. The material expands in
accordance with the radiation, altering the position of the lenses
as a result. This means that the lens is positioned optimally in
relation to the sun at all times.
[0045] FIG. 11 shows the exemplary embodiment of FIG. 10 with a
corrected angle of misalignment 51. In this case, the thermally
expanding material 52b has expanded due to the greater solar
radiation, while the thermally expanding material 52a has shrunk
due to the reduction in solar radiation. Correspondingly, the
tracking plate 55 is now pivoted with respect to the base plate 54,
so that the lenses 30 are directed optimally toward the sun. Now,
the same amount of radiation falls on both the thermally expanding
materials 52a, 52b due to the collimators 53a, 53b so that they do
not change any further.
[0046] FIG. 12 shows the tracking unit for repositioning the lenses
in detail. The collimator 53b is pivoted at an angle 56 with
respect to the verticals on the tracking plate 55. The sensitivity
of the tracking system can be set using this angle and additional
canting. FIG. 10 shows a thermally controlled tracking unit for the
lenses 30.
[0047] It will be appreciated to those skilled in the art having
the benefit of this disclosure that this invention is believed to
provide solar tracking units and components thereof. Further
modifications and alternative embodiments of various aspects of the
invention will be apparent to those skilled in the art in view of
this description. Accordingly, this description is to be construed
as illustrative only and is for the purpose of teaching those
skilled in the art the general manner of carrying out the
invention. It is to be understood that the forms of the invention
shown and described herein are to be taken as the presently
preferred embodiments. Elements and materials may be substituted
for those illustrated and described herein, parts and processes may
be reversed, and certain features of the invention may be utilized
independently, all as would be apparent to one skilled in the art
after having the benefit of this description of the invention.
Changes may be made in the elements described herein without
departing from the spirit and scope of the invention as described
in the following claims.
LIST OF REFERENCE NUMERALS
[0048] 10 Frame [0049] 11 Guide ring [0050] 12 Drive system [0051]
13 Solar cells [0052] 20a-e) Panel [0053] 21a-e) Rotary axis [0054]
22a-e) Central axis panel [0055] 23a-e) Rotation point/Central axis
distance [0056] 24e-d Distance between central axes [0057] 25a-e)
Vertical axis of panel [0058] 26 Angle of pivot [0059] 27 Central
axis spacing [0060] 30 Lens or light collector [0061] 31 Solar
sensor [0062] 32 Principal lens orientation [0063] 41 First bearing
surface [0064] 42 Internal bearing surface [0065] 43 First roller
[0066] 44 Internal roller [0067] 45 Rotary axis [0068] 50 Beams of
sunlight [0069] 51 Angle of discrepancy [0070] 52a,b Thermally
expanding material [0071] 53a,b Collimator [0072] 54 Base plate
[0073] 55 Tracking plate [0074] 56 Collimator pivot angle
* * * * *