WO2015009507A1

WO2015009507A1 - Solar apparatus mount

Info

Publication number: WO2015009507A1
Application number: PCT/US2014/045980
Authority: WO
Inventors: Kyle KATTKE; Kerry Manning; Cory HODGKINS
Original assignee: Abengoa Solar Llc
Priority date: 2013-07-19
Filing date: 2014-07-09
Publication date: 2015-01-22
Also published as: MA38863A1; ZA201601165B

Abstract

Embodiments include solar apparatus mounts comprising a foundation having a side surface supporting a circular or semi-circular azimuth track. The disclosed solar apparatus mount embodiments also include three or more azimuth rollers. The azimuth rollers are operatively engaged with the azimuth track to provide for the horizontal and vertical support, positioning and rotation of a solar apparatus around an azimuth axis.

Description

SOLAR APPARATUS MOUNT

TECHNICAL FIELD

[0001] The embodiments disclosed herein are directed toward solar apparatus mounts and methods of mounting solar apparatus. In particular, the embodiments disclosed herein are directed toward azimuth mounts for any type of solar energy production apparatus including but not limited to a heliostat, photovoltaic panel, Stirling dish reflector or parabolic trough reflector apparatus.

BACKGROUND

[0002] Concentrated Solar Power (CSP) systems utilize reflected solar energy to drive a thermal power cycle for the generation of electricity. In a typical CSP installation a reflective element, for example a heliostat, Stirling dish or parabolic trough reflector, reflects and/or concentrates sunlight on to a receiver element where a working fluid is heated to operational temperatures. Photovoltaic (PV) panels and arrays or concentrated photovoltaic (CPV) systems produce electrical energy by the absorption of sunlight in certain types of semiconductor materials. The efficiency of CSP, CPV installations or PV panels or arrays can be enhanced by assuring that the reflector or PV panel is optimally oriented with respect to the sun. For example a PV panel preferably tracks the apparent motion of the sun such that the panel presents a maximized surface area to the sun throughout the day. Similarly, the heliostat elements of a tower-type CSP installation preferably move with respect to the sun to properly reflect sunlight on to a stationary receiver element throughout the day.

[0003] A large CSP tower installation might be implemented with hundreds or thousands of separately mounted heliostat reflectors distributed in a semicircular (or other) arrangement around each receiver tower. Therefore, the angular relationship of any given heliostat to the sun and the receiver varies with respect to other heliostats in the same installation and varies throughout the day. Accordingly, relatively sophisticated and substantially independent tracking is preferably implemented with each heliostat. A properly equipped solar apparatus mount can provide for the above described tracking. In addition, a solar apparatus mount must be able to withstand the loading placed upon a panel or heliostat in reasonably high wind conditions without premature failure.

[0004] One known type of tracking mount for a solar apparatus includes an azimuth axis about which the reflector or panel is rotated or pivoted. An azimuth axis runs vertically from the ground to the zenith, therefore rotation around an azimuth axis occurs substantially in a horizontal plane. A solar apparatus mount may also include an altitude axis perpendicular to the azimuth axis, providing for the elevation angle of the apparatus to be controlled or adjusted. Certain mounts having azimuth axes and drives, and in particular certain known heliostat mounts featuring an azimuth axis are discussed below.

[0005] A conventional heliostat azimuth mount or bearing is mounted at the top of a centrally positioned pedestal, thus the position of the pedestal corresponds to the location of the azimuth axis. This configuration can cause certain technical challenges. In particular, the pedestal transfers all loads to the ground, typically through a ground-penetrating central foundation. Because the azimuth drive is close to the azimuth axis, low backlash tolerances are required. In addition, a relatively large or stiff pedestal must be utilized to resist the bending moment imposed by heliostat loadings, including but not limited to wind loading. Furthermore, since the foundation is ground penetrating, certain site permit issues may be encountered during installation.

[0006] While not common in commercial implementations, certain heliostat mounts have been designed that utilize an azimuth bearing and/or drive located at least in part on the periphery of a ring type foundation. Ring foundation embodiments address some of the known issues with central pedestal installations, in part by moving the supporting structures of the mount out from near the location of the azimuth axis. Some apparatus mount embodiments which feature a ring type foundation utilize load-bearing azimuth rollers which ride on the upper, substantially horizontal, surface of the ring foundation. The load-bearing azimuth rollers of these mounts rotate around roller axes which are substantially horizontal. This orientation does not allow all external loadings to be reacted by the azimuth rollers, and a secondary central foundation or external non-load bearing rollers are required to maintain the heliostat on the ring foundation during operation. Other designs require a chain or belt element to transfer torque from the motor to the heliostat structure. [0007] For example, the heliostat or Stirling dish mount of US Patent 4,256,088 includes three rollers riding on a perimeter track to achieve azimuth rotation. However, the azimuth rollers ride on the top surface of the track and can only react downward oriented vertical loads. Thus, a central foundation is required to keep the heliostat on the track. Additionally, two of the three rollers must be driven to provide proper motion control through certain wind loading conditions.

[0008] US Patent Application 2012/0042869 describes a cable/pulley system to achieve azimuth rotation. The cable is wrapped around the exterior of a ring which supports the heliostat structure. The heliostat rotates by winding and unwinding the cable. This configuration requires two motors, one master motor for the winder pulley and one slave motor for the unwinder pulley.

[0009] Fig. 1 is a reproduction of Fig. 4 of the heliostat/dish mount of German Patent

DE102007016297. As shown in this figure, the DE102007016297 reference also includes three rollers riding on the substantially horizontal upper surface of a perimeter track to achieve azimuth rotation. This reference describes the use of one motor driven roller. It is unclear however if sufficient contact can be maintained between the roller and the upper surface of the track under all external loading scenarios. According to the DE102007016297 reference, the rollers simply rest on top of the track by virtue of the heliostat weight.

[0010] As shown in Fig. 2, the US Patent 4,129,360 travels on a ring foundation to accomplish azimuthal rotation. However, the azimuth rollers do not react all heliostat loads and an additional, central foundation is required.

[0011] US Patent 4,203,426 utilizes a ring foundation with an azimuth drive track. The azimuth drive mechanism consists of a chain wrapped around the circumference of the foundation. The rollers riding on the foundation act as idlers and are not driven. Not all heliostat loading can be reacted by a single set of idler rollers. For example, the described rollers engaged with the outer diameter surface cannot react vertical loading and the described rollers engaged with the top surface cannot react horizontal or positive vertical loads.

[0012] US Patent 4,209,231 features an azimuth track supported by six ground penetrating foundations. Idler rollers ride on an upper surface of the azimuth track. A chain wraps around a structural ring to achieve azimuth rotation. Thus, this design requires two azimuth rings, one which acts as the track and the other which is engaged with the drive chains. [0013] US Patent 4,870,949 describes a heliostat structure attached to a horizontal ring.

The ring is then supported by rollers fixed to the ground. One of these rollers is driven with a motor/gearbox to achieve azimuth rotation. This design utilizes separate, ground penetrating foundations for each azimuth roller. It is also unclear that the azimuth rollers are able to react all anticipated heliostat external loadings.

[0014] US Patent 4,109,638 describes a solar concentrator which travels about a ring foundation. The mount structure rests on the ring foundation's top surface supported by idler rollers. Supplemental non-load bearing idler rollers engage with the outer diameter surface of the ring foundation. Azimuth rotation is accomplished with a chain or belt wrapped around the structure. The illustrated azimuth rollers cannot react vertical uplift forces.

[0015] The embodiments disclosed herein are directed toward overcoming one or more of the problems discussed above.

SUMMARY OF THE EMBODIMENTS

[0016] Disclosed embodiments include solar apparatus mounts comprising a foundation having a side surface supporting or defining a circular or semi-circular azimuth track. The azimuth track defines an azimuth axis which is substantially vertical. The disclosed solar apparatus mount embodiments also include three or more azimuth rollers engaged with the azimuth track. In certain embodiments, the axes of rotation of the azimuth rollers are

substantially vertical. In use, the azimuth rollers are operatively engaged with the azimuth track to provide for each of the horizontal and vertical support, positioning and rotation of a solar apparatus around an azimuth axis.

[0017] Solar apparatus mount embodiments may also include 2 or more horizontal tension rods operatively engaged with the azimuth rollers. The horizontal tension rods are utilized to cause horizontal force to be applied to the azimuth rollers toward the azimuth track thereby causing the azimuth rollers to be positively engaged with the azimuth track. Certain embodiments will include three azimuth rollers and three horizontal tension rods positioned such that the horizontal tension rods define an equilateral triangle with one azimuth roller being located at each point of the triangle.

[0018] Preferably, the azimuth track is configured to limit the vertical movement of each azimuth roller engaged therewith. For example, the azimuth track may comprise an indentation toward the azimuth axis or protrusion away from the azimuth axis shaped to receive a mating external roller surface of each of the azimuth rollers.

[0019] Various solar apparatus mount embodiments may also include a drive system featuring a drive motor engaged with at least one azimuth roller. The drive system may also include a gearbox, transmission, control elements and sensor/detector elements as required to control the rate at which at least one azimuth roller, engaged with the azimuth track, provides for rotation of the attached mount structures around the azimuth axis. The one or more drive rollers may be engaged with the azimuth track through friction between the roller surface and track surface. As noted above, the horizontal tension rods may be utilized to provide for a positive engagement between the azimuth rollers and the azimuth track. Alternatively the azimuth roller configured as a drive roller and the azimuth track surfaces may be provided with teeth or other structure to facilitate the transfer of drive torque.

[0020] The foundation element of the described solar apparatus mounts may be configured as a ring, for example a cast concrete ring. The solar apparatus attached to the described mount embodiments may be but is not limited to one of a heliostat, a photovoltaic panel, a parabolic trough reflector or a Stirling dish reflector. The described mounts may also be provided with an altitude bearing and/or drive to provide for the solar apparatus to be positioned in elevation around an altitude axis which is substantially perpendicular to the azimuth axis.

[0021] Alternative embodiments include methods of supporting and positioning a solar apparatus with an azimuth mount as described herein. Other alternative embodiments include a solar power generation facility featuring one or more azimuth mounts as described. Other alternative embodiments include methods of generating electricity with a solar power generation facility featuring one or more azimuth mounts as described.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Fig. 1 is a front elevation view of a prior art azimuth mount.

[0023] Fig. 2 is an isometric view of a prior art azimuth mount.

[0024] Fig. 3 is a rear isometric view of an azimuth mount supporting a solar apparatus as disclosed herein.

[0025] Fig. 4 is a front isometric view of the azimuth mount of Fig. 3. [0026] Fig. 5 A is a front elevation schematic diagram showing certain features of an azimuth mount as described herein.

[0027] Fig. 5B is a top plan view schematic diagram of the azimuth mount of Fig. 5A.

[0028] Fig. 5C is a front elevation schematic diagram showing certain features of the engagement with one embodiment of azimuth roller with a corresponding azimuth track as described herein.

[0029] Fig. 6 is a detailed isometric view of the foundation, azimuth track, azimuth roller and horizontal tension rod elements of the azimuth mount of Fig. 3.

[0030] Fig. 7 is a detailed front elevation view of the foundation, azimuth track, azimuth roller and horizontal tension rod elements of the azimuth mount of Fig. 3.

DETAILED DESCRIPTION

[0031] Unless otherwise indicated, all numbers expressing quantities of ingredients, dimensions, reaction conditions and so forth used in the specification and claims are to be understood as being modified in all instances by the term "about".

[0032] In this application and the claims, the use of the singular includes the plural unless specifically stated otherwise. In addition, use of "or" means "and/or" unless stated otherwise. Moreover, the use of the term "including", as well as other forms, such as "includes" and "included", is not limiting. Also, terms such as "element" or "component" encompass both elements and components comprising one unit and elements and components that comprise more than one unit unless specifically stated otherwise.

[0033] The various embodiments disclosed herein include solar apparatus mounts having unique mounting structure providing for the rotation of a solar apparatus around an azimuth axis. As used herein, a solar apparatus includes but is not limited to a heliostat, photovoltaic panel or photovoltaic array, Stirling dish reflector, parabolic trough reflector or other apparatus which in use presents a surface at a selected orientation with respect to the sun to reflect or absorb solar radiation. Many solar apparatus designs therefore include a mount which provides for rotation of the solar apparatus around one or more axes to properly orient the operative surface of the solar apparatus with respect to the apparent motion of the sun throughout the day.

[0034] One type of mount and rotation strategy includes rotation of the solar apparatus through a select angular range of motion around an azimuth axis. As defined herein, an azimuth axis is substantially vertical with respect to the ground. Therefore, an azimuth axis is sometimes referred to as a zenith axis since the azimuth axis extends from the ground toward the zenith. Motion around an azimuth axis is therefore substantially motion in a horizontal plane. A solar apparatus mount which features rotation around an azimuth axis may also, optionally, feature rotation around an altitude axis which is perpendicular to the azimuth axis and therefore parallel with the ground. Motion about the altitude axis adjusts the elevation angle of any solar apparatus attached to the mount.

[0035] Front and rear isometric views of a solar apparatus mount 100 are included in

Figs. 3 and 4. Plan and front elevation schematic diagrams showing certain features of the solar apparatus mount 100 of Figs. 3 and 4 are included in Fig. 5A, 5B and 5C. With reference to Figs. 3-5, it may be noted that the solar apparatus mount 100 includes a foundation 102. The foundation 102 comprises at least one side surface 104 supporting or defining a circular or semicircular azimuth track 106. An alternative configuration with a ring or partially ring-shaped foundation will include at least two side surfaces, one on the outside of the ring and another on the inside of the ring. The foundation 102 may be fabricated from cast concrete, formed metal or another material. In certain embodiments the foundation will be fabricated to have sufficient mass to at least in part provide stability to the solar apparatus mount 100 under wind or other loading.

[0036] The side surface of the foundation 104 can be a substantially vertical side-surface such as shown in Figs. 3 and 4. The embodiments disclosed herein are not however limited to foundations 102 featuring a vertical side surface. The azimuth track 106 may be a flat or structured surface carved, molded or otherwise formed in to or extending out from the side surface 104 of the foundation 102. Alternatively, the azimuth track 106 may be a separate structure mounted to the foundation or co-formed with the foundation. In an embodiment featuring a ring shaped foundation 102, the azimuth track could be formed in an inner side surface or an outer side surface.

[0037] The azimuth track 106 defines a circular or semicircular track located within a substantially horizontal plane. Thus, as best shown in the plan and front elevation views of Fig. 5 A and 5B, the center of rotation defined by the azimuth track 106 coincides with the location of a substantially vertical azimuth axis 108. As described in more detail below, the solar apparatus mount 100 and any solar apparatus attached thereto may be made to rotate through a select angle around the azimuth axis 108 through operation of the various elements disclosed herein.

[0038] The solar apparatus mount 100 also includes three or more azimuth rollers 110 operatively engaged with the azimuth track 106. As used herein, the terms "operatively engaged with," shall include any mechanical communication or any type of contact between the azimuth rollers 110 and the azimuth track 106 such that the rollers may roll or be driven around the side surface and/or perimeter of the azimuth track 106 while supporting other mount elements. Thus, each azimuth roller element may include, but is not limited to, one or more wheels, one or more axles, one or more carriages, frames, bearing or other supporting structures. The solar apparatus mount 100 includes at a minimum three azimuth rollers 110. Additional azimuth rollers 110 may be provided if desired, for example to provide additional load bearing capacity. In embodiments featuring only three azimuth rollers 110, the rollers will be arranged in a triangle in the horizontal plane. The triangle formed by the azimuth rollers 110 may be, but is not limited to, an equilateral triangle centered on the azimuth axis 108.

[0039] As noted above, the azimuth rollers 110 are operatively engaged with the side surface of the azimuth track. Various types of engagement are possible. For example, as shown in the plan and front elevation views of Figs. 5 A and 5B, engagement with the azimuth track may be accomplished in certain embodiments by providing each of the three or more azimuth rollers 110 with at least one wheel which rotates about a roller axis of rotation 112 which is substantially vertical. Alternatively, as shown in Fig. 5C, engagement with the azimuth track may be accomplished with rollers having non- vertical roller axis engaged with a correspondingly oriented azimuth track 106.

[0040] Therefore, as shown in Figs. 3-5, the azimuth rollers 110 may engage the azimuth track 106 around the perimeter of the azimuth track. As described in more detail below, inward force may be applied to the azimuth rollers 110 in a horizontal plane, preferably toward the azimuth axis center of rotation, to positively engage the azimuth rollers 110 with the azimuth track 106. In an embodiment with a ring shaped foundation 102, the azimuth rollers 110 may engage the azimuth track around an interior side surface of the ring and force may be applied generally outward to positively engage the azimuth rollers 110 with the azimuth track 106. It is important to note that the azimuth track 106 may be a relatively complex structure as described below or, alternatively, may be as simple as a zone defined around a portion of the side surface 104 of the foundation 102.

[0041] The solar apparatus mount 100 also includes various mount structures connecting a solar apparatus to the azimuth rollers 110. For example, as shown in Fig. 3, rods 114, stays 116 or other structures are operatively engaged with the three or more azimuth rollers 110 and provide for the support and rotation of the solar apparatus 118 attached thereto. The solar apparatus 118 shown in Figs. 3-5 is a reflective heliostat; however the solar apparatus 118 could in alternative embodiments be a photovoltaic panel, photovoltaic array, Stirling dish reflector, parabolic trough reflector or other solar apparatus.

[0042] In certain embodiments, the solar apparatus mount 100 includes at least two horizontal tension rods 120 operatively engaged with the azimuth rollers 110. In embodiments where three azimuth rollers 110 are utilized, it is advantageous to have three horizontal tension rods 120 which define a triangle with one azimuth roller 110 being located at each point of the triangle. Similarly, an embodiment with four azimuth rollers 110 can advantageously be implemented with two crossed or four horizontal tension rods 120 extending from roller to roller. In any configuration, the horizontal tension rods 120 cause force to be applied to the azimuth rollers 110 in a horizontal direction which is therefore normal to the azimuth axis. In some embodiments, the force applied by the tension rods 120 is also directed toward the azimuth axis 108. In other embodiments the net force applied to each azimuth roller 110 is generally inward but not necessarily directed toward the location of the azimuth axis 108.

[0043] In the particular but non-limiting configuration shown in Figs. 3-5, the horizontal tension rods 120 provide net force in the direction of the arrows labeled "A." Therefore, as noted above, the horizontal tension rods 120 serve to force the azimuth rollers 110 into engagement with the azimuth track 106.

[0044] The horizontal tension rods 120 may, in certain embodiments, be implemented with springs, cables or other flexible elements. In a more typical rod configuration, the horizontal tension rods 120 are implemented with rods or poles that may include threads which may be engaged with nuts or other coupling members to impart horizontal tensile force to the azimuth rollers 110. Alternatively, the rods 120 may include turnbuckle structures or other means to adjust the rod length and provide tensile force to the azimuth rollers 110. [0045] The embodiments disclosed herein may be implemented without the use of any rollers contacting the upper horizontal surface of the foundation. Accordingly, the engagement between the azimuth rollers 110 and azimuth track 106 is relied upon to limit the vertical motion of the azimuth rollers 110 and attached apparatus. In particular, the engagement of the azimuth rollers 110 with the azimuth track 106 prevents the downward movement of the azimuth rollers 110 caused by the weight or wind loading of the mount and apparatus and also prevents upward movement of any azimuth roller caused by wind induced torque, wind induced lift or an off- center apparatus balance point.

[0046] One configuration of azimuth track 106 and azimuth rollers 110 which limits vertical motion is shown in Fig. 5C, where the angled upper and lower rollers 110 engage with the angled surfaces of the azimuth track 106 to substantially limit or prevent vertical motion under any reasonable loading scenario. Another configuration of azimuth track 106 and azimuth roller 110 which limits vertical motion is shown in the detailed views of Figs. 6 and 7. In the Fig. 6-7 embodiments, the azimuth track is configured as a trough or channel which includes inwardly extending curved or flat portions or a combination thereof. In any configuration, for example the configuration shown in Fig. 7, the azimuth track can include flat or curved surfaces which are generally facing downward 121, flat or curved surfaces 122 that are generally vertical and flat or curved surfaces 124 which are generally facing upward. Thus, a roller having a mating external roller profile 126 may mate with the selected azimuth track profile and thereby be restricted from vertical movement while driving or rolling against surfaces 121 and 124. It is important to note that the actual configuration of the profile of the azimuth track and the corresponding external profile of the azimuth rollers 126 can be varied as desired and made more or less complex in order to provide vertical stability to the azimuth rollers 110. For example, the track and roller profiles may define multiple corresponding channels, may have one or more horizontal or vertical stops, may be toothed, may include protrusions from the track, may include one or more "V" shaped channels or protrusions or otherwise be structured to function as described.

[0047] An azimuth track 106 having a selected profile may be integrated into or co- formed with the foundation 102. For example, the foundation 102 may be constructed of concrete which is pre-cast at a central facility on or off site. The azimuth track profile can be cast into the foundation 102 during fabrication or carved into the foundation 102 in a subsequent fabrication step. Alternatively, the azimuth track 106 may comprise a ring of another material, for example, galvanized steel with a select profile which is incorporated into the foundation during the casting or attached to the foundation later.

[0048] The embodiments disclosed herein will also typically include a drive system or drive mechanism providing for the powered and preferably controlled rotation of the solar apparatus 118 around the azimuth axis 108. In certain embodiments, the drive mechanism may be implemented with a drive motor 128 which is engaged with one or more of the azimuth rollers 110. An azimuth roller 110 which is engaged with the drive motor 128 is referred to as a drive roller herein. Typically, sufficient normal force is applied to the drive rollers 110 for drive traction and apparatus stability under anticipated wind loads by the horizontal tension rods 120. Therefore, only one azimuth roller is required to be driven and the remaining rollers may function as idlers. When the solar apparatus 118 becomes externally loaded for example under high wind conditions, the tension rods 120 maintain a minimum normal force on all rollers independent of apparatus and wind orientation.

[0049] The drive motor 128 may be directly engaged with the drive roller(s), although it is more typically necessary to connect the motor to the drive roller (or drive rollers) through a gear box or other transmission. As noted above, the drive roller can rely upon friction only to transmit torque to the azimuth track 106 and foundation 102. Alternatively, simple friction engagement may be supplemented with, or replaced by, a positive mechanical engagement drive. For example, teeth can be embedded into the azimuth track 106 and the driven roller replaced with a gear (spur, worm, etc). In this type of mechanical engagement drive embodiment, the drive motor 128 rotates the attached gear which then engages with the toothed azimuth track 106. Teeth in the azimuth track or foundation can be created in a variety of ways, for example embedding a toothed ring into the foundation or carving, molding or otherwise creating teeth out of the foundation material. An alternative azimuth drive system could include a chain or belt wrapped around the foundation and engaged with a drive pulley associated with the drive motor 128, thereby causing each azimuth roller 110 to function as an idler wheel.

[0050] The disclosed embodiments therefore feature a unique engagement between the azimuth rollers 110 and the azimuth track 106. The track profile and mating rollers are designed such that the track substantially limits vertical movement of the azimuth rollers. This allows the rollers advantageously to transmit all loads, whether horizontal, vertical, angled, bending moment or torque in any direction from the mount structure into the foundation. In particular, all load paths in the described embodiments go through the roller assemblies. This configuration eliminates the need for any additional load paths such as an additional central foundation, rollers engaged with the upper horizontal surface of the foundation or in certain embodiments, ground anchors. In other embodiments featuring less massive foundations 102, ground anchors or additional ballast may be desirable.

[0051] An additional advantage of a foundation and mount as described herein is provided by the ability to encode the azimuth track or foundation with fixed features at or near the circumference of the azimuth track 106. For example, as best shown in Figs. 6-7, the foundation 102 or azimuth track 106 may be provided with indicia 130 which may be detected with a sensor as the drive system provides for rotation around the azimuth axis. Feedback may then be provided to a drive controller 132 to control the drive motor 128 and thereby control rotation of all mount elements to optimally track apparent solar motion, provide for absolute apparatus positioning, park the solar apparatus in a predetermined safe position or otherwise control the motion of the mount and apparatus.

[0052] There are several possible methods of implementing the azimuth encoder and detector system generally described above. The sensor element can be a metal proximity, magnetic, optical and/or contact sensor. The detectable features can be slots or other features cut into or affixed to the azimuth track 106 or associated with the foundation 102. Alternatively, the detectable features (represented in the figures as indicia 130) may be implemented with magnetic and/or metal objects or optically detectable markings associated with the foundation 102 or the azimuth track 106. Alternatively, conventional encoders and detectors can be included at or on the drive motor shaft or within the drive transmission.

[0053] The azimuth drive consisting of an azimuth motor 128 and gearbox may be implemented with a low RPM motor such as a stepper motor, or a DC motor connected to a worm drive, planetary gearbox or other suitable transmission. Control circuitry for both the azimuth drive and an optional elevation linear actuator 134 may be included in the controller 132.

[0054] The embodiments disclosed herein are not limited to any particular configuration of mount structure. In the representative example of Fig. 3, the mount structure consists of a pyramid like truss formed by vertical tubes or rods 114 and a diagonal structure of tubes or rods 138. Diagonal tensioning stays 116 connect and tension the vertical rods 114 to provide lateral stability. The illustrative or a similar truss structure advantageously causes the mount rods or tubes to act primarily as compression/tension members, resulting in minimized bending loads.

[0055] Alternative embodiments disclosed herein include methods of supporting a solar apparatus. In method embodiments, a solar apparatus mount is provided as described above. The mount may be driven and controlled as described above to cause the attached solar apparatus to optimally track apparent solar motion. The described mount embodiments may also be used to provide for absolute apparatus positioning, to park the solar apparatus in a predetermined safe position or otherwise to control the motion of the attached solar apparatus.

[0056] Alternative embodiments include solar power generating plants or installations of any configuration featuring solar elements mounted as disclosed herein. Other alternative embodiments include methods of generating electricity with a solar power plant of any configuration featuring solar elements mounted as disclosed herein.

[0057] Various embodiments of the disclosure could also include permutations of the various elements recited in the claims as if each dependent claim was a multiple dependent claim incorporating the limitations of each of the preceding dependent claims as well as the

independent claims. Such permutations are expressly within the scope of this disclosure.

[0058] While the embodiments disclosed herein have been particularly shown and described with reference to a number of alternatives, it would be understood by those skilled in the art that changes in the form and details may be made to the various configurations disclosed herein without departing from the spirit and scope of the disclosure. The various embodiments disclosed herein are not intended to act as limitations on the scope of the claims. All references cited herein are incorporated in their entirety by reference.

Claims

CLAIMS What is claimed is:

1. A solar apparatus mount comprising:

a foundation comprising a side surface supporting or defining a circular or semi-circular azimuth track, wherein the azimuth track defines an azimuth axis which is substantially vertical; three or more azimuth rollers operatively engaged with the azimuth track; and a mount structure operatively engaged with the three or more azimuth rollers providing for the support and rotation of a solar apparatus around the azimuth axis.

2. The solar apparatus mount of claim 1 wherein the three or more azimuth rollers comprise axes of rotation which are substantially vertical.

3. The solar apparatus mount of claim 1 further comprising two or more horizontal tension rods operatively engaged with the three or more azimuth rollers such that the horizontal tension rods cause force to be applied to the three or more azimuth rollers in a direction normal to the azimuth axis.

4. The solar apparatus mount of claim 3 wherein the horizontal tension rods cause force to be applied to the three or more azimuth rollers in a direction toward the azimuth axis.

5. The solar apparatus mount of claim 3 comprising three horizontal tension rods operatively engaged with three azimuth rollers such that the three horizontal tension rods define an equilateral triangle with one azimuth roller being located at each point of the triangle.

6. The solar apparatus mount of claim 1 wherein the azimuth track limits the vertical movement of the three or more azimuth rollers.

7. The solar apparatus mount of claim 6 wherein the azimuth track comprises an indentation toward the azimuth axis shaped to receive a correspondingly shaped external roller surface of the three or more azimuth rollers.

8. The solar apparatus mount of claim 6 wherein the azimuth track comprises a protrusion away from the azimuth axis shaped to receive a correspondingly shaped external roller surface of the three or more azimuth rollers.

9. The solar apparatus mount of claim 6 wherein the azimuth track comprises a plurality of teeth shaped to mate with a plurality of teeth formed in an external roller surface of the three or more azimuth rollers.

10. The solar apparatus mount of claim 1 wherein at least one of the three or more azimuth rollers comprises a drive roller, the solar apparatus mount further comprising a drive mechanism operatively associated with the drive roller which drive mechanism provides for the drive roller to be rotated while engaged with the azimuth track, thereby causing the mount structure to rotate around the azimuth axis.

11. The solar apparatus mount of claim 10 wherein the drive roller is engaged with the azimuth track by friction between an external roller surface and a substantially smooth azimuth track surface.

12. The solar apparatus mount of claim 10 wherein the drive roller is engaged with the azimuth track through mating teeth on an external roller surface and an azimuth track surface.

13. The solar apparatus mount of claim 10 further comprising a controller in electronic communication with the drive mechanism causing the mount structure to rotate around the azimuth axis at a select rate of speed.

14. The solar apparatus mount of claim 1 wherein the foundation comprises a ring having a select thickness between the side surface and an inner ring surface.

15. The solar apparatus mount of claim 14 wherein the foundation comprises a cast concrete ring

16. The solar apparatus mount of claim 1 wherein the solar apparatus comprises one of a heliostat; a photovoltaic panel a parabolic trough reflector or a Stirling dish reflector.

17. The solar apparatus mount of claim 16 wherein the mount structure further comprises an altitude bearing and drive providing for the solar apparatus to be rotated around an altitude axis which is substantially perpendicular to the azimuth axis.

18. The solar apparatus mount of claim 1 further comprising detectable indicia operatively associated with at least one of the azimuth track or the foundation.

19. A method of supporting a solar apparatus comprising:

providing a solar apparatus mount comprising:

a foundation comprising a side surface supporting or defining a circular or semicircular azimuth track, wherein the azimuth track defines an azimuth axis which is substantially vertical;

three or more azimuth rollers operatively engaged with the azimuth track, and a mount structure operatively engaged with the three or more azimuth rollers; engaging the azimuth rollers with the azimuth track;

supporting a solar apparatus with the mount structure.

20. The method of claim 19 further comprising providing the three or more azimuth rollers with axes of rotation which are substantially vertical.

21. The method of claim 19 further comprising:

providing three or more horizontal tension rods operatively engaged with the three or more azimuth rollers; and applying tension to the three or more azimuth rollers with the horizontal tension rods in a direction normal to the azimuth axis.

22. The method of claim 21 further comprising applying tension to the three or more azimuth rollers with the horizontal tension in a direction toward the azimuth axis.

23. The method of claim 19 further comprising limiting vertical movement of the three or more azimuth rollers with the azimuth track.

24. The method of claim 23 wherein the vertical movement of the three or more azimuth rollers is limited by providing an azimuth track comprising an indentation toward the azimuth axis shaped to receive a correspondingly shaped external roller surface of the three or more azimuth rollers.

25. The method of claim 23 wherein the vertical movement of the three or more azimuth rollers is limited by providing an azimuth track comprising a protrusion away from the azimuth axis shaped to receive a correspondingly shaped external roller surface of the three or more azimuth rollers.

26. The method of claim 23 wherein the vertical movement of the three or more azimuth rollers is limited by providing an azimuth track comprising a plurality of teeth shaped to mate with a plurality of teeth formed in an external roller surface of the three or more azimuth rollers.

27. The method of claim 19 wherein at least one of the three or more azimuth rollers comprises a drive roller, the method further comprising:

providing a drive mechanism operatively associated with the drive roller which drive mechanism provides for the drive roller to be rotated while engaged with the azimuth track; and rotating the drive roller to cause the mount structure to rotate around the azimuth axis.

28. The method of claim 27 wherein the drive roller is engaged with the azimuth track by friction between an external roller surface and a substantially smooth azimuth track surface.

29. The method of claim 27 wherein the drive roller is engaged with the azimuth track through mating teeth on an external roller surface and an azimuth track surface.

30. The method of claim 19 further comprising controlling the drive mechanism with a controller in electronic communication with the drive mechanism to cause the mount structure to rotate around the azimuth axis at a select rate of speed.

31. The method of claim 19 wherein the solar apparatus comprises one of a heliostat; a photovoltaic panel a parabolic trough reflector or a Stirling dish reflector.

32. The method of claim 31 wherein the mount structure further comprises an altitude bearing and drive, the method further comprising rotating the solar apparatus around an altitude axis which is substantially perpendicular to the azimuth axis.

33. The method of claim 19 further comprising providing detectable indicia operatively associated with at least one of the azimuth track or the foundation