U.S. patent application number 12/699871 was filed with the patent office on 2011-08-04 for apparatus for pivoting solar troughs on a central axis.
This patent application is currently assigned to KALEX, LLC. Invention is credited to Mark Kalina.
Application Number | 20110186041 12/699871 |
Document ID | / |
Family ID | 44340514 |
Filed Date | 2011-08-04 |
United States Patent
Application |
20110186041 |
Kind Code |
A1 |
Kalina; Mark |
August 4, 2011 |
APPARATUS FOR PIVOTING SOLAR TROUGHS ON A CENTRAL AXIS
Abstract
Solar trough apparatuses are disclosed, where a heat transfer
fluid conduit remains fixed in a focal of a solar trough as the
solar trough tracks the sun. The support structures can be ring or
arcuate structures, where rotation is about their central axis and
the trough is support in them so that the focal zone is coincident
with the axis of rotation and the conduit is situated in the focal
zone eliminating the need for articulated or flexible conduit.
Inventors: |
Kalina; Mark; (Belmont,
CA) |
Assignee: |
KALEX, LLC
Belmont
CA
|
Family ID: |
44340514 |
Appl. No.: |
12/699871 |
Filed: |
February 3, 2010 |
Current U.S.
Class: |
126/601 ;
126/651; 126/694; 126/696; 126/714 |
Current CPC
Class: |
Y02E 10/40 20130101;
F24S 30/425 20180501; Y02E 10/47 20130101; F24S 2030/15 20180501;
F24S 23/74 20180501 |
Class at
Publication: |
126/601 ;
126/694; 126/651; 126/696; 126/714 |
International
Class: |
F24J 2/38 20060101
F24J002/38; F24J 2/12 20060101 F24J002/12; F24J 2/24 20060101
F24J002/24; F24J 2/00 20060101 F24J002/00 |
Claims
1. A solar collector system comprising: a solar trough subsystem
including: a plurality of solar trough sections, where each section
includes one parabolic solar collector or a plurality of parabolic
solar collectors having a focal zone, a heat transfer fluid conduit
subsystem including a conduit extending a length of the trough
subsystem coincident with the focal zone, a support subsystem for
supporting the trough subsystem, where a center of rotation of the
support subsystem is coincident with a focal point, line or zone of
the trough subsystem and where the support subsystem rotates the
trough to track the sun maximizing solar collection, while
maintaining the focal zone fixed and focused on the conduit thereby
maximizing solar heating of a heat transfer fluid flowing through
the conduit stationary and coincident with the focal zone.
2. The system of claim 1, wherein the support structure subsystem
includes a separate trough support structure and a separate conduit
support structure.
3. The system of claim 2, wherein the trough support structure
comprises ring support structures, where the trough support
structures support each trough section and a separate conduit
support structure situated between ring support structures of
adjacent trough sections.
4. The system of claim 2, wherein the trough support structures
comprises arcuate support structures supporting each trough section
and a separate conduit support structure situated between arcuate
structures of adjacent trough sections.
5. The system of claim 2, wherein the trough support structures
comprises ring support structures, where each ring support
structures supports two adjacent trough sections, while
simultaneously supporting the conduit.
6. The system of claim 2, wherein the trough support structures
comprises arcuate support structures, where each arcuate support
structure supports two adjacent trough sections, while
simultaneously supporting the conduit.
7. The system of claim 1, wherein the support structure subsystem
includes a single support structure that supports both the trough
subsystem and the conduit subsystem.
8. The system of claim 7, wherein the trough support structures
comprises ring support structures, where each ring support
structures supports two adjacent trough sections, while
simultaneously supporting the conduit.
9. The system of claim 2, wherein the trough support structures
comprises arcuate support structures, where each arcuate support
structure supports two adjacent trough sections, while
simultaneously supporting the conduit.
10. A method for operating solar collector systems comprising:
providing a solar trough subsystem, a heat transfer fluid conduit
subsystem having a conduit extending a length of the solar trough
subsystem, a support subsystem, and a heat conversion subsystem,
where a center of rotation of the support subsystem is coincident
with the focal zone of the trough subsystem and where the conduit
is coincident with the focal zone of the trough subsystem; focusing
solar radiation on the conduit; and pumping cold heat transfer
fluid through the conduit at a pressure and a flow rate to maximize
heating of the heat transfer fluid to form a hot heat transfer
fluid, while rotating the trough subsystem using the support
subsystem to track the sun maximizing solar collection efficiency
and to maintain a focal zone of the trough subsystem stationary and
where a conduit is situated in the focal zone to maximize heating
without the need for articulated conduit segments.
11. The method of claim 10, further comprising: transferring a
portion of the heat in the hot heat transfer fluid to a working
fluid of a heat conversion subsystem to form a cold heat transfer
fluid.
12. The method of claim 10, converting a portion of the heat in the
working fluid into a useable for of energy in the heat conversion
subsystem.
13. The method of claim 10, further comprising: transferring a
portion of the heat in the hot heat transfer fluid to a working
fluid of a heat conversion subsystem to form a cold heat transfer
fluid, and converting a portion of the heat in the working fluid
into a useable for of energy in the heat conversion subsystem.
13. The method of claim 10, wherein the support structure subsystem
includes a separate trough support structure and a separate conduit
support structure.
14. The method of claim 13, wherein the trough support structure
comprises ring support structures, where the trough support
structures support each trough section and a separate conduit
support structure situated between ring support structures of
adjacent trough sections.
15. The method of claim 13, wherein the trough support structures
comprises arcuate support structures supporting each trough section
and a separate conduit support structure situated between arcuate
structures of adjacent trough sections.
16. The method of claim 13, wherein the trough support structures
comprises ring support structures, where each ring support
structures supports two adjacent trough sections, while
simultaneously supporting the conduit.
17. The method of claim 13, wherein the trough support structures
comprises arcuate support structures, where each arcuate support
structure supports two adjacent trough sections, while
simultaneously supporting the conduit.
18. The method of claim 10, wherein the support structure subsystem
includes a single support structure that supports both the trough
subsystem and the conduit subsystem.
19. The method of claim 18, wherein the trough support structures
comprises ring support structures, where each ring support
structures supports two adjacent trough sections, while
simultaneously supporting the conduit.
20. The method of claim 18, wherein the trough support structures
comprises arcuate support structures, where each arcuate support
structure supports two adjacent trough sections, while
simultaneously supporting the conduit.
21. A solar trough system comprising: a solar trough collector
subsystem, a heat transfer conduit subsystem, and a support
subsystem, where a center of rotation of the support subsystem is
coincident with a focal zone of the trough subsystem and where the
conduit is situated in the focal zone to maximize heating without
articulated conduit segments.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] Embodiments of the present invention relate to solar trough
apparatuses, where a heat transfer fluid conduit remains fixed in a
focal point of the solar trough as the solar trough tracks the
sun.
[0003] More particularly, embodiments of the present invention
relate to solar trough apparatuses, where a heat transfer fluid
conduit remains fixed in a focal point, line or zone of the solar
trough as the solar trough tracks the sun. The solar troughs of
this invention generally include a plurality of trough sections.
The system also includes a support structure, which supports the
trough and conduit and rotates the trough while maintaining the
conduit centered in the focal point, line or zone of the solar
trough eliminating the need for articulated heat transfer fluid
conduits. The support structure can include a separate trough
support structure and a separate conduit support structure or the
support structure can support both the trough and the conduit.
[0004] 2. Description of the Related Art
[0005] Solar thermal troughs are one of three common applications
for solar-thermal energy. They are mechanically simpler and less
costly than solar heliostat towers and are capable of attaining
higher temperatures than Fresnal mirror arrays. Solar troughs
operate by reflecting sunlight from a parabolic mirror and
concentrating it onto a pipe carrying a heat transfer fluid (HTF.)
Once heated, the HTF is sent into a power system to transfer its
heat to a working fluid which then produces power in the power
system.
[0006] However, solar troughs have a significant limitation.
Because the pipes carrying the HTF are mounted above the parabolic
mirrors and the parabolic mirrors must pivot to track the sun, the
pipes carrying HTF must be articulated. The points of articulation
are mechanically complex, require maintenance and limit the
pressure at which HTF can be sent through the pipes. This limited
pressure in turn limits the possible performance of the power
system that generates electricity from the solar-trough heated
HTF.
[0007] Thus, there is a need in the art for improved solar troughs
for use in solar trough type power generation systems that
eliminate the need for articulated heat transfer fluid conduits so
that the solar troughs can track the sun as the rotation assembly
rotates the troughs.
SUMMARY OF THE INVENTION
[0008] Embodiments of the present invention provide solar collector
systems including a solar trough subsystem including a plurality of
solar trough sections. Each section includes one parabolic solar
collector or a plurality of parabolic solar collectors. The troughs
are supported by a support subsystem, where a center of rotation of
the support subsystem is coincident with a focal point, line or
zone of the trough subsystem and where the support subsystem
rotates the trough to track the sun maximizing solar collection,
while maximizing heat transfer fluid heating passing through the
conduit stationary and coincident with the focal zone. The systems
also include a heat transfer fluid conduit subsystem that extends a
length of the trough subsystem coincident with the focal zone. The
support structure subsystem can include a separate trough support
structure and a separate conduit support structure or a single
support structure that supports both the trough subsystem and the
conduit subsystem. In certain embodiments, the trough support
structures comprises ring support structures, where the trough
support structures support each trough section and a separate
conduit support structure situated between ring support structures
of adjacent trough sections. In other embodiments, the support
structures comprises arcuate support structures supporting each
trough section and a separate conduit support structure situated
between arcuate structures of adjacent trough sections. In the
other embodiments, the support structure comprises ring support
structures, where each ring support structures supports two
adjacent trough sections, while simultaneously supporting the
conduit. In other embodiments, the support structure comprises
arcuate support structures, where each arcuate support structure
supports two adjacent trough sections, while simultaneously
supporting the conduit. The rotation of the trough by the support
structure permits the trough to track the sun maximizing solar
collection, while maintaining the focal zone focused on the conduit
without having motion of the conduit because the conduit is
situated coincident with the focal zone of the trough.
[0009] Embodiments of this invention provide methods for operating
solar collector systems including providing a solar trough
subsystem, a heat transfer fluid conduit subsystem, a support
subsystem, and a heat conversion subsystem, where a center of
rotation of the support subsystem is coincident with the focal zone
of the trough. The support subsystem rotates the trough to track
the sun maximizing solar collection efficiency, while maintaining a
focal zone of the trough stationary and where a conduit of the
conduit subsystem is situated in the focal zone to maximize heating
without the need for articulated conduit segments. The methods
include focusing solar radiation on the heat transfer fluid conduit
coincident with a focal zone of the solar trough. The methods also
include pumping a cold heat transfer fluid through the conduit at a
pressure and a flow rate to maximize heating of the heat transfer
fluid to form a hot heat transfer fluid. The methods include
rotating the trough, while pumping, to track the sun, while
maintaining the focal line or zone substantially stationary
maximizing solar collection and simultaneously maximizing heat
transfer fluid heating. The methods also include transferring a
portion of the heat in the hot heat transfer fluid to a working
fluid of a heat conversion subsystem to form a cold heat transfer
fluid. The methods also include converting a portion of the heat in
the working fluid into a useable for of energy in the heat
conversion subsystem.
[0010] Embodiments of this invention provide solar trough system
including a solar trough collector subsystem, a heat transfer
conduit subsystem, and a support subsystem, where a center of
rotation of the support subsystem is coincident with a focal zone
of the trough and where the conduit is situated in the focal zone
to maximize heating without articulated conduit segments. The
methods include focusing solar radiation on the heat transfer fluid
conduit coincident with a focal zone of a solar trough. The methods
also include pumping a cold heat transfer fluid through the conduit
at a pressure and a flow rate to maximize heating of the heat
transfer fluid to form a hot heat transfer fluid. The methods
include rotating, while pumping, the trough to track the sun, while
maintaining the focal line or zone substantially stationary to
track the sun maximizing solar collection and simultaneously
maximizing heat transfer fluid heating.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The invention can be better understood with reference to the
following detailed description together with the appended
illustrative drawings in which like elements are numbered the
same:
[0012] FIG. 1A depicts a front view of an embodiment of a trough
apparatus of this invention facing the horizon including two trough
sections, two rings supporting each section, separate conduit
supports and support and wheel drive assemblies.
[0013] FIG. 1B depicts an end view of the trough apparatus of FIG.
1A.
[0014] FIG. 1C depicts a front view of the trough apparatus of FIG.
1A with the trough facing up, sun at its apex.
[0015] FIG. 1D depicts an end view of the trough apparatus of FIG.
1C.
[0016] FIG. 1E depicts a front view of another embodiment of a
trough apparatus of this invention facing the horizon including two
trough sections, two rings supporting each section and the conduit
and support and wheel drive assemblies.
[0017] FIG. 1F depicts an end view of the trough apparatus of FIG.
1E.
[0018] FIG. 2A depicts a front view of another embodiment of a
trough apparatus of this invention facing the horizon including two
trough sections and toothed rings shared between sections to
support the sections and support and gear drive assemblies, where
the conduit is supported by the rings.
[0019] FIG. 2B depicts a front view of the apparatus of FIG. 2A,
with the trough facing up.
[0020] FIG. 2B depicts an end view of the trough apparatus of FIG.
2A.
[0021] FIG. 3A depicts a front view of another embodiment of a
trough apparatus of this invention facing the horizon including two
trough sections, two rings per section including a hollow member,
where the rings are supported on a pedestal with a drive unit for
each ring.
[0022] FIG. 3B depicts an end view of the trough apparatus of FIG.
3A.
[0023] FIG. 3C depicts a front view of another embodiment of a
trough apparatus of this invention facing the horizon including two
trough sections, two rings per section including a hollow member
extending between sections, where the hollow member and the rings
are supported on a pedestal with a drive unit.
[0024] FIG. 4A depicts an end view of another embodiment of a
trough apparatus of this invention facing the horizon including an
arc rotatable structures and support and wheel drive
assemblies.
[0025] FIG. 4B depicts an end view of another embodiment of a
trough apparatus of this invention facing the horizon including a
toothed arcuate rotatable structures and support and gear drive
assemblies.
[0026] FIG. 4C depicts an end view of another embodiment of a
trough apparatus of this invention facing the horizon including a
toothed arcuate rotatable structures and support and gear drive
assemblies.
[0027] FIG. 5A depicts a cross-section of a drive unit of this
invention including transverse wheels situated in a groove of the
ring or arcuate structures.
[0028] FIG. 5B depicts a cross-section of a gear drive unit of this
invention for toothed ring or arcuate structures.
[0029] FIG. 5C depicts cross-section of a gear drive unit of this
invention including with aindented toothed ring or arcuate
structures.
DETAILED DESCRIPTION OF THE INVENTION
[0030] The inventor has found that solar trough systems can be
constructed with non-articulated pipes or conduits. Solar trough
systems including non-articulated heat transfer fluid (HTF) pipes
or conduits can be pressurized to any pressure that does not exceed
a rupture pressure of the pipe, while articulated pipe or conduits
assemblies have a more limited operating pressure. The inventor has
also found that without articulation, there are no conduit bearings
or joints to maintain or risk failure, and the costs of
articulating the HTF pipes and maintaining the articulated pipes
are not incurred.
[0031] The invention operates by making an axis of rotation of a
solar trough the same as a focal zone of the trough so that an axis
of a HTF pipe can be made coincident with the focal zone of the
trough. As the trough rotates to track the sun, its focal zone
maintains fixed or substantially fixed as does the pipe or conduit,
which remains stationary or substantially stationary within the
focal zone of the trough. Because the focal zone is coincident with
the axis of rotation of the trough, the heat transfer fluid conduit
remains fixed or stationary.
[0032] In a conventional solar trough apparatus, an axis of
rotation of the trough is set at a bottom of a parabolic mirror or
trough. A motor mounted on elevated pedestals or struts holds up
the trough and rotates it to track the sun. The HTF pipe is held in
a focal point of the trough by further struts. At the edges of the
trough, the HTF pipe is attached to articulated or flexible pipe
sections so the pipe moves as the trough rotates to maintain the
pipe in the focal zone of the trough.
[0033] In embodiments of this invention, the solar trough system
comprising a solar trough including a plurality of trough sections.
The system also includes a heat transfer conduit subsystem and a
support subsystem. The support subsystem supports and rotates the
trough so that the trough tracks the sun, while maintaining a
trough focal zone fixed or substantially fixed, i.e., the axis of
rotation of the trough is coincident with its focal zone or line.
The support subsystem also supports the conduit, where the conduit
is situated coincident with the focal zone of the trough. In
certain embodiments, the support subsystem comprises ring support
structures. In certain embodiments, each section includes two ring
support structures per trough section, one positioned at each end
of the trough sections. In other embodiments, adjacent sections
share a single ring support structure so that there are N+1 ring
support structures instead of 2N ring support structures. The ring
support structures include a means for rotating the ring support
structures. There are a variety of ring support structures that can
be used to support and rotate the rings, where the center of
rotation is coincident with the focal zone of the trough. The HTF
conduit extends the length of the trough and is situated or
supported coincident with the axis of rotation of the rings. The
conduit support structures can be separate from the ring support
structures or the conduit can be supported by the ring support
structure. In certain cases, the solar trough and support rings do
not actually touch the HTF conduit, which is supported by its own
struts. In all cases, the HTF pipe, therefore, does not move, and
requires no articulation because the center of rotation of the
trough is coincident with the focal zone of the trough.
[0034] Embodiments of the solar trough systems and apparatuses
include two rings, mounted perpendicularly on either end of a
parabolic solar trough assembly and a heat transfer fluid pipe or
conduit, where the pipe extends between the rings and is positioned
so that the pipe passes through a center of each ring so that the
pipe is substantially coincident with a focal axis or zone of the
parabolic solar trough assembly. The parabolic trough and its
underlying support structure is then affixed to the rings by means
of several struts supporting the trough from beneath and connecting
it to the inside of the ring. The diameter of the rings is such
that, with the focal point of the trough as the center of the ring,
the trough touches the ring at the trough's widest point.
[0035] Suitable heat transfer fluids for use in this invention
include, without limitation, meltable salts, synthetic heat
transfer fluids such as THERMINOL.RTM. (a registered trademark of
Solutia Inc. Corporation) and DOWTHERM.RTM. (a registered trademark
of Dow Chemicals Corporation), natural heat transfer fluids, other
fluids capable of acting as a heat transfer fluid, and mixtures or
combinations thereof.
[0036] Suitable working fluids for use in this invention include,
without limitation, a multi-component working fluid including at
least one lower boiling component and at least one higher boiling
component. In certain embodiments, the working fluids include an
ammonia-water mixture, a mixture of two or more hydrocarbons, a
mixture of two or more freon, a mixture of hydrocarbons and freon,
or the like. In general, the fluid can comprise mixtures of any
number of compounds with favorable thermodynamic characteristics
and solubility. In certain embodiments, the fluid comprises a
mixture of water and ammonia.
DETAILED DESCRIPTION OF THE DRAWINGS
[0037] Two Ring Supports Per Trough Section with Conduit
Supports
[0038] Referring now to FIG. 1A, a front view of an embodiment of a
solar trough apparatus of this invention, generally 100, is shown
to include two trough sections 102, a heat transfer conduit 104 and
three conduit supports 106. In this view, the trough is facing the
horizon as would be the case at such rise and sunset. Each trough
section 102 includes a parabolic solar trough 108 and two ring
support assemblies 110. Each ring support assembly 110 includes a
ring structure 112 and a drive support and drive assembly 114. The
support and drive assemblies 114 can be frictional engagements
drives well known in the art or a gear drive such as an
intermeshing gear drive or any other drive capable to rotating the
ring structures about the central axis. Of course, it should be
recognized that in most apparatuses, there will be a large
plurality of sections, but each section will be supported as shown
for the above two sections
[0039] Referring now to FIG. 1B, an end view of the solar trough
apparatus of FIG. 1A is shown to include a trough section 102, a
heat transfer conduit 104 and a conduit support 106. The trough
section 102 includes a parabolic solar trough 108 and a ring
support assembly 110. The ring support assembly 110 includes a ring
structure 112 and support and wheel drive assemblies 114. The ring
structure 110 includes a plurality of parabolic solar trough
support struts 116, here three, mounted on an inner surface 118 of
the ring structure 112. The trough struts 116 support and hold the
parabolic trough 108 fixed so that its focal zone is coincident
with the conduit 104. Each support and wheel drive assemblies 114
here include a frictional engagement wheel 120 and a support and
wheel drive unit 122, which turns the wheel 120 about it axile 124,
which in turn turns the ring structure 112. The drive unit 122
rotates the ring structure 112 at a rate to maximize solar
radiation concentrated on the conduit 104. The two ring structures
112 of this embodiment support the weight of the trough 108. The
ring structures 112 are in turn supported on ring support and wheel
drive assemblies 114 that rotate the ring structures 112 about
their axes so that the conduit 104 remains stationary in the focal
zone of the trough. Each ring structure 112 rests on a pair of
wheels 120 of the drive assemblies 114 set up underneath the ring
structure 112, so that each wheel 120 is equally offset from the
conduit 104 held in the center of the ring 112. The wheels 120 are
arranged so that the bottom of the ring structure 112 does not
touch the ground. The wheels 120, which must bear the weight of the
rings 112 and the trough 108, which the rings 112 support, are in
turn supported by wheel support and wheel drive units 114, which
hold the wheels 120 on their axles 124 and turn the wheels 120
about their axles 124. The units 114 are affixed to the ground and
must bear the weight of the wheels 120 and ring structures 112. The
units 114 hold the wheels 120 so that the bottom of each wheel 120
also does not touch the ground.
[0040] Referring now to FIGS. 1C&D, a front and end view of the
apparatus of FIGS. 1A&B, where the trough is facing up as would
occur when the sun is at its apex.
Two Ring Supports Per Trough Section without Conduit Supports
[0041] Referring now to FIG. 1E, a front view of an embodiment of a
solar trough apparatus of this invention, generally 100, is shown
to include two trough sections 102 and a heat transfer conduit 104.
In this view, the trough is facing the horizon as would be the case
at sun rise and sunset. Each trough section 102 includes a
parabolic solar trough 108 and two ring support assemblies 110.
Each ring support assembly 110 includes a ring structure 112 and
drive support and wheel drive assemblies 114. The support and wheel
drive assemblies 114 can be frictional engagements drives well
known in the art or a gear drive such as an intermeshing gear drive
or any other drive capable to rotating the ring structures about
the central axis. In this embodiment, the conduit 104 is supported
by the ring structures 112. Of course, it should be recognized that
in most apparatuses, there will be a large plurality of sections,
but each section will be supported as shown for the above two
sections
[0042] Referring now to FIG. 1F, an end view of the solar trough
apparatus of FIG. 1E is shown to include a trough section 102 and a
heat transfer conduit 104. The trough section 102 includes a
parabolic solar trough 108 and a ring support assembly 110. The
ring support assembly 110 includes a ring structure 112 and drive
support and wheel drive assemblies 114. The ring structure 112
includes a plurality of parabolic solar trough support struts 116,
here three, mounted on an inner surface 118 of the ring structure
112. The trough struts 116 support and hold the parabolic trough
108 fixed so that its focal zone is coincident with the conduit
104. The ring structure 112 also includes a plurality of conduit
struts 126 attached to a bushing, a slip ring or bearings 128 to
allow the ring structures 112 to rotate freely about the supported
conduit 104. The conduit struts 126 and the bushing, slip ring or
bearings 128 support the conduit 104, which is situated inside the
bushing, slip ring or bearings 128 so that the ring structure 112
can rotate, while the conduit 104 remains stationary. Each support
and wheel drive assemblies 114 here include a frictional engagement
wheel 120 and a support and wheel drive unit 122, which turns the
wheel 120 about it axile 124, which in turn turns the ring
structure 112. The drive unit 122 rotates the ring structure 112 at
a rate to maximize solar radiation concentrated on the conduit 104.
The two ring structures 112 of this embodiment support the weight
of the trough 108. The ring structures 112 are in turn supported on
ring support and wheel drive assemblies 114 that rotate the ring
structures 112 about their axes so that the conduit 104 remains
stationary in the focal zone of the trough. Each ring structure 112
rests on a pair of wheels 120 of the drive assemblies 114 set up
underneath the ring structure 112, so that each wheel 120 is
equally offset from the conduit 104 held in the center of the ring
112. The wheels 120 are arranged so that the bottom of the ring
structure 112 does not touch the ground. The wheels 120, which must
bear the weight of the rings 112 and the trough 108, which the
rings 112 support, are in turn supported by wheel support and wheel
drive units 114, which hold the wheels 120 on their axles 124 and
turn the wheels 120 about their axles 124. The units 114 are
affixed to the ground and must bear the weight of the wheels 120
and ring structures 112. The units 114 hold the wheels 120 so that
the bottom of each wheel 120 also does not touch the ground.
[0043] An advantage of this variant is that the drive motors,
whether driving one of the supporting wheels or a dedicated drive
wheel, are mounted at ground level, making access and maintenance
simpler than in the prior art, where the drive motors to rotate the
solar trough are mounted at the top of the support struts which
hold up the solar trough. A further advantage is that a single
powerful drive motor could be installed (with a chain transmission,
for instance) to turn all the drive wheels of an entire row of
solar troughs, replacing one or more separate small motors for each
trough, as is the case in the prior art.
Rings Share Ring Supports
[0044] Referring now to FIG. 2A, a front view of an embodiment of a
solar trough apparatus of this invention, generally 200, is shown
to include two trough sections 202 and a heat transfer conduit 204.
In this view, the trough is facing the horizon as would be the case
at sun rise and sunset. Each trough section 202 includes a
parabolic solar trough 208. The apparatus 200 also includes ring
support assemblies 210. In this embodiment, adjacent sections share
a support assembly. Each ring support assembly 210 includes a
toothed ring structure 212 and a drive support and gear drive
assembly 214. The support and gear drive assemblies 214 can be
frictional engagements drives well known in the art or a gear drive
such as an intermeshing gear drive or any other drive capable to
rotating the ring structures about the central axis. Of course, it
should be recognized that in most apparatuses, there will be a
large plurality of sections, but each section will be supported as
shown for the above two sections.
[0045] Referring now to FIG. 2B, a front view of the solar trough
apparatus of FIG. 2A is shown, when the trough have rotates and are
facing up.
[0046] Referring now to FIG. 2C, an end view of the solar trough
apparatus of FIG. 2A is shown to include a trough section 202 and a
heat transfer conduit 204. The trough section 202 includes a
parabolic solar trough 208 and a ring support assembly 210. The
ring support assembly 210 includes a toothed ring structure 212 and
a support and gear drive assembly 214. The ring structure 212
includes a plurality of parabolic solar trough support struts 216,
here three, mounted on an inner surface 218 of the toothed ring
structure 212. The trough struts 216 support and hold the parabolic
trough 208 fixed so that its focal zone is coincident with the
conduit 204. The toothed ring structure 212 also includes a
plurality of conduit struts 226 attached to a bushing, a slip ring
or bearings 228 to allow the ring structures 212 to rotate freely
about the supported conduit 204. The conduit struts 226 and the
bushing, slip ring or bearings 228 support the conduit 204, which
is situated inside the bushing, slip ring or bearings 228 so that
the ring structure 212 can rotate, while the conduit 204 remains
stationary. Each support and gear drive assemblies 214 here include
a drive gear 220 and a support and drive unit 222, which turns the
gear 220 about it axile 224, which in turn turns the toothed ring
structure 212. The drive unit 222 turns the gear 220 that rotates
the toothed ring structure 212 at a rate to maximize solar
radiation concentrated on the conduit 204. The toothed ring
structure 212 of this embodiment supports the weight of the trough
208. The toothed ring structures 212 are in turn supported on ring
support and drive assemblies 214 that rotate the toothed ring
structures 212 about their axes so that the conduit 204 remains
stationary in the focal zone of the trough. Each toothed ring
structure 212 rests it support and gear of the drive assembly 214
set up underneath the toothed ring structure 212 so that the ring
structure 212 does not touch the ground.
Rings Share Ring Supports
[0047] Referring now to FIG. 3A, a front view of an embodiment of a
solar trough apparatus of this invention, generally 300, is shown
to include two trough sections 302 and a heat transfer conduit 304.
In this view, the trough is facing the horizon as would be the case
at sun rise and sunset. Each trough section 302 includes a
parabolic solar trough 308. The apparatus 300 also includes ring
support assemblies 310. The ring support assembly 310 includes two
ring structures 312, two drive units 314 and a support pedestal
316. Each ring structure 312 includes a ring 318, a central hollow
tubular member 320 and ring supports 322. The trough 308 is
supported by the rings 318, where the ends 324 of the trough 308
extend only partially into the rings 318 to provide room for the
ring supports 322. The drive units 314 can be frictional
engagements drives well known in the art or a gear drives or any
other drive capable to rotating a ring structure about its central
axis. Of course, it should be recognized that in most apparatuses,
there will be a large plurality of sections, but each section will
be supported as shown for the above two sections.
[0048] Referring now to FIG. 3B, an end view of the solar trough
apparatus of FIG. 3A is shown. The ring structure 312 includes a
plurality of parabolic solar trough support struts 326, here three,
mounted on an inner surface 328 of the toothed ring structure
312.
[0049] Referring now to FIG. 3C, a front view of another embodiment
of a solar trough apparatus of this invention, generally 350, is
shown to include two trough sections 352 and a heat transfer
conduit 354. In this view, the trough is facing the horizon as
would be the case at sun rise and sunset. Each trough section 352
includes a parabolic solar trough 358. The apparatus 350 also
includes ring support assemblies 360. The ring support assembly 360
includes two ring structures 362, a drive unit 364 and a support
pedestal 366. The drive units 364 cooperate to turn sections 352 as
two sections are rotated by each drive unit 364. The apparatus 352
need not have a drive unit 364 associated with the pedetals at the
end of the apparatus. Each ring structure 362 includes a ring 368,
a central hollow tubular member 370 and ring supports 372. The
trough 358 is supported by the rings 368, where the ends 374 of the
trough 358 extend only partially into the rings 368 to provide room
for the ring supports 372. The drive units 364 can be frictional
engagements drives well known in the art or a gear drives or any
other drive capable to rotating a ring structure about its central
axis. Of course, it should be recognized that in most apparatuses,
there will be a large plurality of sections, but each section will
be supported as shown for the above two sections.
[0050] In the second variant, each ring has supporting struts that
attach the ring to a centered hollow pipe (which is of greater
diameter than the HTF pipe.) For each ring, the hollow pipe
projects out away from the trough, along the axis of rotation. Each
ring is then supported by a large strut which is topped with a
short section of pipe which is just large enough to hold the outer
diameter of the hollow pipe attached to the ring. In this way,
these large struts, which are set to either side of the
ring-and-trough apparatus, support the ring-and-trough apparatus,
holding it clear of the ground and allowing it to rotate about the
axis of the HTF pipe. It should be noted that the HTF pipe itself
passes through the pipe sections at the center of the rings and
does not touch them.
[0051] In the second variant, a drive motor is placed on the struts
holding up the entire rings-and-trough apparatus and rotates the
apparatus about the axis of the HTF pipe to track the sun. It is
possible to use a single drive motor per strut or one per
apparatus, with the motor-less strut made so as to allow for free
and smooth rotation of the apparatus (for instance, by means of
ball bearings.)
Arcuate Support Structures
[0052] Referring now to FIG. 4A, an end view of the solar trough
apparatus, generally 400, is shown to include a trough section 402,
a heat transfer conduit 404 and a conduit support 406. The trough
section 402 includes a parabolic solar trough 408 and an arcuate
support assembly 410. The arcuate support assembly 410 includes an
arcuate structure 412 and support and wheel drive assemblies 414.
The arcuate structure 412 includes a plurality of parabolic solar
trough support struts 416, here three, mounted on an inner surface
418 of the arcuate structure 412. The trough struts 416 support and
hold the parabolic trough 408 fixed so that its focal zone is
coincident with the conduit 404. Each support and wheel drive
assemblies 414 here include a frictional engagement wheel 420 and a
wheel drive unit 422, which turns the wheel 420 about it axile 424,
which in turn turns the arcuate structure 412. The drive unit 422
rotates the arcuate structure 412 at a rate to maximize solar
radiation concentrated on the conduit 404. The arcuate structure
412 of this embodiment supports the weight of the trough 408. The
arcuate structure 412 is in turn supported on support and wheel
drive assemblies 414 that rotate the arcuate structures 412 about
their axes so that the conduit 404 remains stationary in the focal
zone of the trough. Each arcuate structure 412 rests on a pair of
wheels 420 of the drive assemblies 414 set up underneath the
arcuate structure 412, so that each wheel 420 is equally offset
from the conduit 404 held in the center of the arcuate 412. The
wheels 420 are arranged so that the bottom of the arcuate structure
412 does not touch the ground. The wheels 420, which must bear the
weight of the arcuate structure 412 and the trough 408, which the
arcuate structure 412 supports, are in turn supported by wheel
support and wheel drive units 414, which hold the wheels 420 on
their axles 424 and turn the wheels 420 about their axles 424. The
units 414 are affixed to the ground and must bear the weight of the
wheels 420 and arcuate structures 412. The units 414 hold the
wheels 420 so that the bottom of each wheel 420 also does not touch
the ground.
[0053] Referring now to FIG. 4B, an end view of the solar trough
apparatus, generally 400, shown to include a trough section 402, a
heat transfer conduit 404 and a conduit support 406. The trough
section 402 includes a parabolic solar trough 408 and a arcuate
support assembly 410. The arcuate support assembly 410 includes a
toothed arcuate structure 412 and a support and gear drive assembly
414. The arcuate structure 412 includes a plurality of parabolic
solar trough support struts 416, here three, mounted on an inner
surface 418 of the toothed arcuate structure 412. The trough struts
416 support and hold the parabolic trough 408 fixed so that its
focal zone is coincident with the conduit 404. Each support and
gear drive assemblies 414 here include a drive gear 420 and a
support and drive unit 422, which turns the gear 420 about it axile
424, which in turn turns the toothed arcuate structure 412. The
drive unit 422 turns the gear 420 that rotates the toothed arcuate
structure 412 at a rate to maximize solar radiation concentrated on
the conduit 404. The toothed arcuate structure 412 of this
embodiment supports the weight of the trough 408. The toothed
arcuate structures 412 are in turn supported on arcuate support and
drive assemblies 414 that rotate the toothed arcuate structures 412
about their axes so that the conduit 404 remains stationary in the
focal zone of the trough. Each toothed arcuate structure 412 rests
it support and gear of the drive assembly 414 set up underneath the
toothed arcuate structure 412 so that the arcuate structure 412
does not touch the ground.
[0054] Referring now to FIG. 4C, an end view of the solar trough
apparatus, generally 400, is shown to include a trough section 402
and a heat transfer conduit 404. The trough section 402 includes a
parabolic solar trough 408 and a arcuate support assembly 410. The
arcuate support assembly 410 includes a arcuate structure 412 and a
drive support and gear drive assembly 414. The arcuate structure
412 includes a plurality of parabolic solar trough support struts
416, here three, mounted on an inner surface 418 of the arcuate
structure 412. The trough struts 416 support and hold the parabolic
trough 408 fixed so that its focal zone is coincident with the
conduit 404. The arcuate structure 412 also includes a plurality of
conduit struts 426 attached to a bushing, a slip arcuate or
bearings 428 to allow the arcuate structures 412 to rotate freely
about the supported conduit 404. The conduit struts 426 and the
bushing, slip arcuate or bearings 428 support the conduit 404,
which is situated inside the bushing, slip arcuate or bearings 428
so that the arcuate structure 412 can rotate, while the conduit 404
remains stationary. Each support and gear drive assemblies 414 here
include a drive gear 420 and a support and drive unit 422, which
turns the gear 420 about it axile 424, which in turn turns the
toothed arcuate structure 412. The drive unit 422 turns the gear
420 that rotates the toothed arcuate structure 412 at a rate to
maximize solar radiation concentrated on the conduit 404. The
toothed arcuate structure 412 of this embodiment supports the
weight of the trough 408. The toothed arcuate structures 412 are in
turn supported on arcuate support and drive assemblies 414 that
rotate the toothed arcuate structures 412 about their axes so that
the conduit 404 remains stationary in the focal zone of the trough.
Each toothed arcuate structure 412 rests it support and gear of the
drive assembly 414 set up underneath the toothed arcuate structure
412 so that the arcuate structure 412 does not touch the
ground.
[0055] An advantage of this variant is that the drive motors,
whether driving one of the supporting wheels or a dedicated drive
wheel, are mounted at ground level, making access and maintenance
simpler than in the prior art, where the drive motors to rotate the
solar trough are mounted at the top of the support struts which
hold up the solar trough. A further advantage is that a single
powerful drive motor could be installed (with a chain transmission,
for instance) to turn all the drive wheels of an entire row of
solar troughs, replacing one or more separate small motors for each
trough, as is the case in the prior art.
[0056] Note that one experienced in the art can engineer other
alternate variants and mechanisms to support the solar-trough and
allow it to pivot with the HTF pipe as its axis of rotation.
[0057] Note also than a third conceptual variant is possible, where
instead of ensuring that there is no contact between the HTF pipe
and the solar-trough apparatus, instead the solar-trough apparatus
is suspended from the HTF pipe in such a way as to allow the
solar-trough apparatus to rotate about the axis of the solar trough
pipe. In this variant, motors would be mounted around the HTF pipe,
allowing the solar-trough apparatus to rotate about the pipe, which
would be fixed and immobile. In this variant, the HTF pipe would
have to be made far stronger (and likely more costly) than in the
other variants described above, since it would have to constantly
carry the weight of the solar-trough apparatus, as well as the
motors required to rotate the solar-trough apparatus. However, this
is, none the less, a possible way of having the solar trough
apparatus rotate with about the axis of the HTF pipe.
[0058] There are several advantages offered by the proposed
invention.
[0059] Firstly, because (in the first and second variants
described) the HFT pipe is not in contact with the trough apparatus
and does not move, it can be built (in all variants) with no
articulation, reducing installation and maintenance costs and more
crucially, allowing for much higher pressurization of the HTF in
the pipe, in turn allowing for better performance of the power
system.
[0060] Secondly, (in the first variant described) it is possible to
reduce the number of drive motors and to place these motors at
ground level, making maintenance easier and less expensive.
[0061] Thirdly, the entire trough can be mounted lower to the
ground, reducing construction costs and easing both maintenance and
the cleaning of the mirror surface of the trough.
[0062] Fourth, (in the first and second variants described) because
the HTF pipe is not attached to the trough, cleaning the mirror
surface of the is made much easier; there are no struts projecting
from the surface of the trough.
[0063] Lastly, the lack of struts projecting from the surface of
the trough means that the trough can be a single continuous mirror,
improving its overall ability to focus sunlight onto the HTF pipe.
The total area of shadow cast by the ring structures holding the
trough in the proposed invention can be made smaller than the
shadows cast by the struts projecting from the trough used to hold
the HTF pipe in the prior art.
[0064] In summary, the present invention should reduce the cost of
installation of solar troughs (with their associated HTF pipes,)
reduce the costs of maintenance and cleaning of solar troughs and
by allowing higher pressure in the HTF pipes, increase the
performance and thus the power generation of a given surface area
of solar troughs.
Alternate Drive Assemblies
[0065] Referring now to FIG. 5A, a cross-sectional view of a
traverse wheel drive unit, generally 500, is shown to include a
ring or arcuate structure 502 having two grooves 504 and a drive
wheels 506 (motor not shown) for frictionally rotating the
structure 502.
[0066] Referring now to FIG. 5B, a cross-sectional view of a
traverse wheel drive unit, generally 500, is shown to include a
toothed ring or arcuate structure 502 and a gear drive 504 (motor
not shown) rotating the structure 502.
[0067] Referring now to FIG. 5C, a cross-sectional view of a
traverse wheel drive unit, generally 500, is shown to include a
ring or arcuate structure 502 having a grooves 504 including
internal teeth 506 and a gear drive 508 (motor not shown) for the
structure 502.
[0068] It should be recognized that although several different
drive units and mechanisms have been shown, that any drive system
capable of rotating the ring or arcuate structures will do as well
including, without limitation, belt drives, direct drives, fluid
drives, or the like. Additionally, the drives can utilize electric
motors or internal combustion engines.
[0069] All references cited herein are incorporated by reference.
Although the invention has been disclosed with reference to its
preferred embodiments, from reading this description those of skill
in the art may appreciate changes and modification that may be made
which do not depart from the scope and spirit of the invention as
described above and claimed hereafter.
* * * * *