US20110186041A1

US20110186041A1 - Apparatus for pivoting solar troughs on a central axis

Info

Publication number: US20110186041A1
Application number: US12/699,871
Authority: US
Inventors: Mark Kalina
Original assignee: Kalex LLC
Current assignee: Kalina Power Ltd
Priority date: 2010-02-03
Filing date: 2010-02-03
Publication date: 2011-08-04
Also published as: WO2011097308A2; WO2011097308A3

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.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention
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.
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.
2. Description of the Related Art
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.
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.
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

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.
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.
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

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:

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.

FIG. 1B depicts an end view of the trough apparatus of FIG. 1A.

FIG. 1C depicts a front view of the trough apparatus of FIG. 1A with the trough facing up, sun at its apex.

FIG. 1D depicts an end view of the trough apparatus of FIG. 1C.

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.

FIG. 1F depicts an end view of the trough apparatus of FIG. 1E.

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.

FIG. 2B depicts a front view of the apparatus of FIG. 2A, with the trough facing up.

FIG. 2B depicts an end view of the trough apparatus of FIG. 2A.

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.

FIG. 3B depicts an end view of the trough apparatus of FIG. 3A.

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.

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.

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.

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.

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.

FIG. 5B depicts a cross-section of a gear drive unit of this invention for toothed ring or arcuate structures.

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

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.
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.
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.
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.
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.
Suitable heat transfer fluids for use in this invention include, without limitation, meltable salts, synthetic heat transfer fluids such as THERMINOL® (a registered trademark of Solutia Inc. Corporation) and DOWTHERM® (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.
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

Two Ring Supports Per Trough Section with Conduit Supports
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
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.
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
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
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.
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

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.
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.
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

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.
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.
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.
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.
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

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.
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.
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.
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.
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.
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.
There are several advantages offered by the proposed invention.
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.
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.
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.
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.
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.
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

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.
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.
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.
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.
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.

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

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.