U.S. patent application number 13/001855 was filed with the patent office on 2011-05-12 for heliostat joint.
This patent application is currently assigned to PRATT & WHITNEY ROCKETDYNE., INC.. Invention is credited to Ronald Daniel, Alan B. Minick.
Application Number | 20110108019 13/001855 |
Document ID | / |
Family ID | 41707625 |
Filed Date | 2011-05-12 |
United States Patent
Application |
20110108019 |
Kind Code |
A1 |
Minick; Alan B. ; et
al. |
May 12, 2011 |
HELIOSTAT JOINT
Abstract
A heliostat includes a joint with a range of motion in both
elevation and azimuth of more than 90 degrees.
Inventors: |
Minick; Alan B.; (Madison,
AL) ; Daniel; Ronald; (Brownsboro, AL) |
Assignee: |
PRATT & WHITNEY ROCKETDYNE.,
INC.
Canoga Park
CA
|
Family ID: |
41707625 |
Appl. No.: |
13/001855 |
Filed: |
August 18, 2009 |
PCT Filed: |
August 18, 2009 |
PCT NO: |
PCT/US2009/054124 |
371 Date: |
December 29, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61089843 |
Aug 18, 2008 |
|
|
|
Current U.S.
Class: |
126/600 |
Current CPC
Class: |
F24S 30/455 20180501;
F24S 25/10 20180501; Y02E 10/47 20130101; F24S 2030/135
20180501 |
Class at
Publication: |
126/600 |
International
Class: |
F24J 2/38 20060101
F24J002/38 |
Claims
1. A heliostat comprising: a joint with a range of motion in both
elevation and azimuth of more than 90 degrees.
2. The heliostat as recited in claim 1, further comprising a
pedestal to which said joint is mounted, said pedestal defines a
first radius, said joint includes an offset in which a heliostat
array azimuthal axis of rotation is displaced at least said first
radius from said pedestal longitudinal axis.
3. The heliostat as recited in claim 1, wherein said joint provides
a range of motion in both elevation and azimuth of approximately
180 degrees.
4. The heliostat as recited in claim 1, wherein said joint includes
no singularity point.
5. The heliostat as recited in claim 1, further comprising a drive
system which positions a heliostat array relative to a
pedestal.
6. The heliostat as recited in claim 5, wherein said drive system
defines two points on said heliostat array and said joint defines
one point on said heliostat array.
7. The heliostat as recited in claim 6, wherein said two points are
defined in part by a respective drive rod.
8. The heliostat as recited in claim 7, wherein each of said
respective drive rods includes a lead screw.
9. The heliostat as recited in claim 7, wherein each of said
respective drive rods are mounted to said pedestal through an
offset arm structure.
10. A heliostat comprising: a pedestal which defines a longitudinal
axis, said pedestal defines a first radius; a first link movably
mounted to said pedestal about a first axis; and a second link
movably mounted to said first link about a second axis, said second
axis displaced from said longitudinal centerline by at least said
first radius.
11. The heliostat as recited in claim 10, wherein said first axis
is a longitudinal axis.
12. The heliostat as recited in claim 11, wherein said second axis
is an azimuthal axis.
13. The heliostat as recited in claim 10, wherein said second axis
is perpendicular to said first axis.
14. The heliostat as recited in claim 10, further comprising a
heliostat array mounted to said second link.
15. The heliostat as recited in claim 14, further comprising a
drive system which positions said heliostat array relative to a
pedestal.
16. The heliostat as recited in claim 15, wherein said drive system
includes two points attached to said heliostat array, said two
points defined in part by a respective drive rod.
17. A heliostat comprising: a joint having a first member and a
second member, wherein the first member has an axis of rotation
that is skew to an axis of rotation of the second member, wherein
the axis of the first member is offset a first distance from the
axis of the second member, and wherein the second member has a
radial length about the second axis at least approximately 1/2 of
the first distance.
18. The heliostat as recited in claim 17, wherein said radial
length is at least equal to said first distance.
19. The heliostat as recited in claim 17, wherein said joint
provides a range of motion in both elevation and azimuth greater
than 90 degrees.
20. The heliostat as recited in claim 17, wherein said joint
provides a range of motion in both elevation and azimuth of
approximately 180 degrees.
Description
[0001] The present disclosure claims priority to U.S. Provisional
Patent Disclosure Ser. No. 61/089,843, filed Aug. 18, 2008.
BACKGROUND
[0002] The present disclosure relates to a heliostat, and more
particularly to a joint therefor. Current heliostats may have a
relatively limited range of motion both in azimuth as well as in
elevation. The relatively limited range of motion may require
configuration changes for best operation at different field
positions and at different latitudes. This may result in the use of
different heliostat configurations in different fields or even in
different parts of the same field to focus the sun's energy on the
receiver.
[0003] The relatively limited range of motion may also require some
heliostats to reposition themselves 180 degrees at specific times
during the day to continue tracking the sun. This action typically
requires approximately 15 minutes during which the sun's energy is
not captured.
SUMMARY
[0004] A heliostat according to an exemplary aspect of the present
disclosure includes a joint with a range of motion in both
elevation and azimuth of more than 90 degrees.
[0005] A heliostat according to an exemplary aspect of the present
disclosure includes a pedestal which defines a longitudinal axis,
the pedestal defines a first radius. A first link is movably
mounted to the pedestal about a first axis. A second link movably
mounted to the first link about a second axis, the second axis
displaced from the longitudinal centerline by at least the first
radius.
[0006] A heliostat according to an exemplary aspect of the present
disclosure includes a joint having a first member and a second
member, wherein the first member has an axis of rotation that is
skew to an axis of rotation of the second member, wherein the axis
of the first member is offset a first distance from the axis of the
second member, and wherein the second member has a radial length
about the second axis at least approximately 1/2 of the first
distance.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] Various features will become apparent to those skilled in
the art from the following detailed description of the disclosed
non-limiting embodiment. The drawings that accompany the detailed
description can be briefly described as follows:
[0008] FIG. 1 is a general schematic view of a solar power tower
system for use with the present invention;
[0009] FIG. 2 is a perspective view of a heliostat;
[0010] FIG. 3A is a side view of a heliostat with the heliostat
array in a first position;
[0011] FIG. 3B is a top view of a heliostat with the heliostat
array in a second position;
[0012] FIG. 4 is a perspective view of a first link for a joint for
the heliostat;
[0013] FIG. 5 is a perspective view of a second link for a joint
for the heliostat;
[0014] FIG. 6 is a perspective view of another embodiment of the
first link for a joint for the heliostat;
[0015] FIG. 7A is a side view of a heliostat with the heliostat
array in the first position illustrating a drive system;
[0016] FIG. 7B is a top view of a heliostat with the heliostat
array in a second position illustrating a drive system;
[0017] FIG. 8 is a top expanded view of the drive system; and
[0018] FIG. 9 is a side expanded view of the drive system.
DETAILED DESCRIPTION
[0019] Referring to FIG. 1, a solar power tower system 20 includes
a high concentration central receiver system 22 having a receiver
24 coupled to a tower structure 25 at a predetermined height above
ground to receive solar radiation S from a multiple of sun-tracking
mirrors or heliostats 26. Molten salt or other thermal transfer
fluid is communicated from a cold storage tank system 28 through
the central receiver system 22 and heated. The heated thermal
transfer fluid is then communicated to a hot storage tank system
30. When power is required, the hot thermal transfer fluid is
pumped to a steam generator system 32 that produces steam. The
steam drives a steam turbine/generator system 34 that creates
electricity for communication to a power grid. From the steam
generator, the thermal transfer fluid is returned to the cold
storage tank system 28 for storage until reheated in the central
receiver system 22 while the steam is recovered through a condenser
system 36. It should be understood that although a particular
component arrangement is disclosed in the illustrated embodiment,
any arrangement which makes use of heliostats will also benefit
from the present disclosure.
[0020] Referring to FIG. 2, the heliostat 26 generally includes a
pedestal 40, a joint 42, a frame assembly 44, and a heliostat array
46. The pedestal 40 supports the joint 42 to permit articulation of
the frame assembly 44 and thus the heliostat array 46 to track the
sun and focus the solar radiation S as required.
[0021] Referring to FIG. 3A, the pedestal 40 may be a generally
cylindrical column which defines a longitudinal centerline A and a
radius r1 (FIG. 3B). A semi-spherical cap 48 in the disclosed,
non-limiting embodiment tops the pedestal 40.
[0022] The joint 42 generally includes a first link 50 and a second
link 52. The first link 50 includes a first arcuate arm 54 with end
pivots 54A, 54B and a second arcuate arm 56 with end pivots 56A,
56B. The end pivots 54A, 54B, as illustrated define an initial
elevation axis B and the end pivots 56A, 56B defines an initial
azimuthal axis C (also illustrated in FIG. 4). The end pivots 54A,
54B are oriented relative the end pivots 56A, 56B such that axis B
is transverse to axis C. In one non-limiting embodiment axis B is
perpendicular to axis C.
[0023] The second link 52 includes an arcuate arm 58 with end
pivots 58A, 58B (FIG. 5) which engages the end pivots 56A, 56B of
the first link 50 (along axis C). Alternatively, the first link 50'
includes a single end pivot 56C (FIG. 6).
[0024] The first link 50 is movably mounted to the pedestal 40
about axis B. The second link 52 is movably mounted to the first
link 50 about axis C. That is, axis C is offset by at least the
column radius r1 relative to the longitudinal centerline A by axis
B to achieve a significant freedom of motion. The second link 52
positions the heliostat array 46 at least an additional radius r1
from axis C to provide essentially unrestricted azimuth and
elevation motion of the heliostat array 46 relative to the pedestal
40. By using the elevational axis B to achieve the offset, the
joint 42 provides a significant range of motion in both elevation
and azimuth. In one non-limiting embodiment, the range of motion is
more than 90 degrees and typically approximately 180 degrees in
both elevation and azimuth. It should be understood that the
heliostat array 46 may be mounted asymmetrically as desired to
optimize load and other operating characteristics and
requirements.
[0025] Through the unique combination of kinematics, a full range
of smooth and continuous motion with no singularity conditions is
achieved. The range of motion avoids any unique non-sun gathering
maneuvers.
[0026] Referring to FIG. 7A, a drive system 70 attached between the
pedestal 40 and the heliostat array 46 at two points e, f on the
heliostat array 46 defines the orientation and position of the
heliostat array 46. The drive system 70 generally includes two
drive rods 72A, 72B such as lead screws attached between the
heliostat array 46 through mounts 74A, 74B and the pedestal 40
through offset aims 76A, 76B (FIG. 7B).
[0027] The drive system 70 adjusts the heliostat array 46 relative
to the pedestal 40 to provide articulation to utilize the range of
motion provide by the joint 42. The joint 42 essentially provides
one point g in space for the heliostat array 46. By defining the
two other points e, f as represented by the mounts 74A, 74B the
definition and orientation of the heliostat array 46 plane is
established. In this manner, there is no singularity point and no
need to significantly realign the azimuth to continue tracking the
sun. Instead, sun tracking is accomplished in a smooth and
continuous manner.
[0028] Each of the drive rod 72A, 72B are attached to the mounts
74A, 74B through joints 78A, 78B such as a ball-joint or U-joint to
provide a universal connection therebetween. The mounts 74A, 74B
support the respective joints 78A, 78B to permit rotation and
articulation of the respective drive rod 72A, 72B to position the
heliostat array 46.
[0029] Referring to FIG. 8, each offset arm 76A, 76B generally
includes a shoulder 80, an arm 82, a forearm 84, a rotational
bearing 86, a wrist rotator 88 and a drive motor 90. A pivot 92
between the shoulder 80 and the arm 82 permits movement of the arm
82 in a plane P transverse to the pedestal 40 and generally
parallel to ground G (FIG. 7A). It should be understood the plane P
may be alternatively oriented.
[0030] The wrist rotator 88 is mounted to the forearm 84 through
the rotational bearing 86 such that the wrist rotator 88 may rotate
about the forearm 84 (illustrated schematically by axis F and arrow
F). The rotational bearing 86 may essentially include a sleeve
which permits rotation F.
[0031] The wrist rotator 88 includes a turntable 96 which permits
rotation (illustrated by arrow W) of the drive motor 90 and thus
the drive rod 72A about an axis W (also illustrated in FIG. 9).
That is, the wrist rotator 88 supports the drive motor 90 through
which the drive rod 72 may be extended and retracted along axis Y
through, for example, a threaded engagement with the lead screw. It
should be understood that other drive motors such as linear
electric motors or other telescopic arrangements may alternatively
or additionally be provided. The turntable 96 may include
rotational couplings to communicate electrical power and controls
signals to the respective drive motor 90.
[0032] The shoulder 80, arm 82 and forearm 84 provide an offset to
provide full motion and avoid overextension of the drive rod 72A,
72B. The arm 82 and forearm 84 may each be of a length which is at
least equivalent to the radius r1. The arm 82 and forearm 84 may
alternatively be of a longer or shorter length dependant in part on
whether more or less than a 180 degree range of motion is to be
provided. The drive rods 72A, 72B may be maintained in tension when
extended and only experience compressive loading when at reduced
extension.
[0033] The joint 42 facilitates an extended operational range for
the heliostat 26 with a robust drive system 70 for effective
control and actuation of heliostat 26. Unique maneuvers are avoided
and relatively uncomplicated and reliable hardware supports the
heliostat array 46.
[0034] It should be understood that like reference numerals
identify corresponding or similar elements throughout the several
drawings. It should also be understood that although a particular
component arrangement is disclosed in the illustrated embodiment,
other arrangements will benefit herefrom.
[0035] Although particular step sequences are shown, described, and
claimed, it should be understood that steps may be performed in any
order, separated or combined unless otherwise indicated and will
still benefit from the present disclosure.
[0036] The foregoing description is exemplary rather than defined
by the limitations within. Various non-limiting embodiments are
disclosed herein, however, one of ordinary skill in the art would
recognize that various modifications and variations in light of the
above teachings will fall within the scope of the appended claims.
It is therefore to be understood that within the scope of the
appended claims, the disclosure may be practiced other than as
specifically described. For that reason the appended claims should
be studied to determine true scope and content.
* * * * *