SUPPORT STRUCTURE FOR A SOIAR COLLECTOR SYSTEM

Field of the Invention

The present invention relates to support structures for a solar collector system.

Background of the Invention

Solar collectors for collecting solar energy generally fall into one of two categories: concentrating and non-concentrating. Concentrating solar collectors typically comprise a reflector for reflecting and concentrating received solar radiation towards an absorber. The absorber may include a conduit for carrying a heat transfer fluid for absorbing solar thermal energy and/or an array of photovoltaic cells for converting solar energy into electrical energy. The reflector is either in the form of a circular dish with the focal position above the center of the dish, or a trough-like, parabolic reflector which produces a line focus along the length of the reflector. In the latter case, the absorber typically comprises a radiation absorbing tube positioned centrally above the reflector and extending along its length.

Focussing or concentrating solar collectors typically require some type of sun tracking mechanism and tracking control system to vary the orientation of the collector to maintain the focal position of the solar radiation of the absorber surface. Non-focusing solar collectors generally comprise flat, solar absorbing panels which are fixed in position and do not actively track the sun.

An example of a trough-like solar collector system is disclosed in WO 2005/090873. The solar collector

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SUBSTITUTE SHEET (RULE JS*

comprises a parabolic trough-like reflector having a longitudinal absorber positioned above the reflector and mounted thereon by means of a central support upstanding from the reflector. The reflector includes spaced apart ribs fixed to the underside of the reflector panel to help maintain the shape of the reflective surface. The absorber comprises a longitudinal plate having a radiation absorbing surface which may include an array of solar cells mounted thereon. A conduit is positioned adjacent the back of the plate for transferring solar thermal energy into a heat transfer fluid. Transparent panels extend from each side of the absorber to opposed longitudinal edges of the reflector to protect the reflective surface from weathering and to provide additional structural rigidity.

Aspects and embodiments of the invention are directed to improved support structures of a solar collector .

Summary of the Invention

According to one aspect of the present invention, there is provided a support structure for a solar collector comprising support means spaced radially from an upwardly directed rotational axis of said support structure and one or more bearing members for supporting and engaging said support means to enable said support structure to rotate about said rotational axis.

According to another aspect of the present invention, there is provided a solar collector positioned above a defined space allocated for parking a vehicle.

According to another aspect of the present invention, there is provided a support structure for

2 SUBSTTTtJTC SHEET(RUlE 28}

supporting a solar collector above a defined space allocated for parking a vehicle, the support structure comprising a plurality of upright members, spaced apart in a configuration such that each member is positioned substantially between spaces allocated for parking one or more vehicles.

According to another aspect of the present invention, there is provided a driving mechanism for driving rotation of a support structure for supporting one or more solar collectors, comprising a cable attached to the support structure and a drum or capstan for pulling said cable on rotation thereof.

According to another aspect of the present invention, there is provided a support structure for a solar collector comprising support means spaced radially from an upwardly directed rotational axis of said support structure and one or more bearing members for supporting and engaging said support means to enable said support structure to rotate about said rotational axis.

In some embodiments, the laterally extending member extends about the post.

In some embodiments, the laterally extending member comprises an auger.

In some embodiments, the auger has a relatively shallow pitch. For example, the pitch may be 45° or less or 35° or less.

In some embodiments, the support further comprises a second laterally extending member having a surface area which extends in a plane directed substantially along the longitudinal axis of the post and which extends transversely

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8ϋBβTmjTε SHEET (RULS W)

of the longitudinal axis of the post, and which, when positioned in the ground, resists displacement of the post in a direction normal to the surface area (i.e. transverse to the longitudinal axis of the post) .

According to another aspect of the present invention, there is provided a support for supporting a solar collector comprising a post for positioning in the ground having a laterally extending member extending laterally from the post, and having a surface area which extends in a plane generally directed along the longitudinal axis of the post, and which, when positioned in the ground resists displacement of the post in a direction normal to the surface area (i.e. transverse to the longitudinal axis of the post) .

In some embodiments, the laterally extending member extends from the post at a position intermediate between the lower end of the post and the surface of the ground.

In some embodiments, the laterally extending member is closer to the ground than the lower end of the post, for example adjacent or near the surface of the ground.

According to another aspect of the present invention, there is provided a support system for a solar collector comprising an upright member having an upper portion, mounting means adjacent the upper portion for mounting a solar collector thereto, and a structure for supporting the upright member and extending transversely thereof.

SUBSTITUTE SHEET (RULE 2β)

According to another aspect of the present invention, there is provided a support structure for a plurality of solar collectors, the support structure having mounting means for mounting the collectors at different heights which form an angle approximately equal to the latitude location on the planet.

According to another aspect of the present invention, there is provided a support structure for supporting a plurality of solar collectors comprising a respective pivotal mounting for pivotally mounting each solar collector to the support structure to allow each solar collector to tilt up and down about a transverse axis, i.e. in a vertical plane, and a. mounting system for rotatably mounting the support structure for azimuth rotation.

According to other aspects and embodiments of the invention, a solar collector ground mounting system comprises an anchor post which may be buried or augured into the ¹ ground, at a depth below the frost line, if any, and having a pivotal mounting for pivotally mounting a solar collector thereto and/or for mounting a tilt actuator element .

In some aspects and embodiments of the invention, a lateral force support encloses and/or is attached to the post at a position proximate and below ground surface, and is attached to the post to prevent lateral motion and/or vertical motion of the post. In some embodiments, a low pitch auger tip is rigidly fixed to the anchor post and may be augured into the ground, or a hole may be dug and the post assembly buried and back filled.

In some embodiments, the post comprises solid wood, square or round hollow structural section and may for

5 βUβSTmjTE SHEET (RULI Mf

example comprise thin walled aluminum or steel or other similar structural material.

In some aspects and embodiments of the invention, a surface mounting system comprises a plurality of structural sections which may comprise metal that are clamped and/or interconnected without welding or metal fusing to support a solar collector on a surface such as a building roof with limited point load support capability.

In some embodiments, metal or other structural material forming clamps may be fastened with rivets or bolts or other affixing devices to rigidly connect tubular sections together. In some embodiments, one or more load spreading pads may be provided to increase the uniformity of weight distribution and wind load to a substrate below the support structure which may for example comprise a sensitive membrane building roof.

In some embodiments, internal or external joiner extrusion (s) using bolts, rivets, screws or other suitable fasteners may be used to rigidly connect support sections together.

In some embodiments, clamps may be provided for interconnecting parts of the structure which may be stamped from tough steel or stainless steel or other material, where the ultimate strength of the material is substantially higher than the yield strength.

In some aspects and embodiments of the invention, a mounting system is provided for mounting a plurality of collectors thereto in a manner such that the collectors are stacked at an angle approximately equal to the latitude location on the planet. Each collector may be mounted to

SUBSTITUTE SHEET {RULE 2βJ

enable the tilt angle of the collector to vary for solar tracking. Optionally, the mounting system may comprise a rotational mounting support for enabling azimuth rotation.

In some embodiments, azimuth angle may be measured by any suitable measuring device such as an electronic compass or rotary position transducer and may be provided to a system controller for controlling the azimuth angle.

In some embodiments, the azimuth rotational support system includes a circular track supported on a suitable substrate or rigidly attached to a number of posts.

In some embodiments, the pivot support and actuator attach bracket may be the same part and are clamped to the structural support sections with a stamped or molded bracket, allowing the actuator to be mounted beside, rather than through the structural member, or may be affixed thereto by any other suitable means.

Other aspects and embodiments of the invention may comprise any combination of features disclosed herein.

Brief Description of the Drawings

Examples of embodiments of the present invention will now be described with reference to the drawings, in which:

Figure 1 shows a perspective view of a support structure for a solar collector system according to an embodiment of the present invention;

Figure 2 shows a side view of the support structure shown in Figure 1;

SUBSTITUTESHEET(RUlE28)

Figure 3 shows a front view of the support structure shown in Figure 1;

Figure 4 shows a top view of the support structure shown in Figure 1;

Figure 5 shows a support structure for a solar collector system according to another embodiment of the present invention;

Figure 6 shows a side view of the support structure shown in Figure 5;

Figure 7 shows a front . view of the support structure shown in Figure 5;

Figure 8 shows a top view of the support structure shown in Figure 5;

Figure 9 shows a perspective view of a support structure according to another embodiment of the present invention;

Figure 10 shows a side view of the support structure shown in Figure 9;

Figure 11 shows a front view of the support structure shown in Figure 9;

Figure 12 shows a top view of the support structure shown in Figure 9;

Figure 13 shows an array of support structures, each support structure being similar to that shown in Figure 9;

SUBSTITUTE SHEET (RULE 2β)

Figure 14A shows a front and part sectional view of an embodiment of a support bearing assembly according to an embodiment of the present invention;

Figure 14B shows a side view of the bearing assembly shown in Figure 14A;

Figure 15 shows a mechanism for driving rotation of a support structure according to an embodiment of the present invention;

Figure 16A shows an array of solar collectors each with a ground mounting and anchoring system according to an embodiment of the present invention;

Figure 16B shows a perspective view of an upper support for use in the embodiment of Figure 16A;

Figure 16C shows a perspective view of an alternative upper support for use in the embodiment of Figure 16A;

Figure 17 shows a perspective view of a solar collector and an alternative mounting system according to an embodiment of the present invention;

Figure 18 shows a perspective view of a solar collector and mounting system according to another embodiment of the present invention;

Figure 19 shows a graph of the available solar energy from various tracking configurations as a function of time;

Figure 2OA shows an array of solar collectors according to an embodiment of the present invention mounted on a two axis tracking system;

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Figure 2OB shows a part cross-sectional view of a support bearing and track arrangement according to an embodiment of the invention;

Figure 21 shows an array of solar collectors mounted on a ground anchored two axis tracking system according to an embodiment of the present invention; and

Figure 22 shows an array of solar collectors on a roof mounted two axis tracking system according to an embodiment of the present invention.

Description of Embodiments

Figures 1 to 4 show various views of a support structure 101 for supporting an array of solar collectors 103a to 103f. In this embodiment, each solar collector comprises an elongate, trough-like reflector for receiving and concentrating solar energy, and a longitudinal absorber 105 spaced from the reflector for absorbing reflected solar radiation. In other embodiments, the solar collector may comprise any other form of solar collector, for example flat panel or dish type.

The support structure 101 comprises a generally circular support ring 107 and a plurality of support members 108 spaced circumferentially around the support ring 107 for rotatably supporting the ring about its central axis 109 (Figure 4) . Each support member comprises a lower mounting plate or pad 111 which can be positioned and mounted on a suitable substrate, for example a roof of a building, the ground or other suitable substrate (not shown) . In this embodiment, the support ring 107 has a generally rectangular cross section having opposed longer sides which are generally upright or vertical and opposed

10 βUBSTπUTC SHEET (RULE 28)

shorter sides which are generally horizontal. Each support member comprises a bearing member such as a roller bearing for engaging the bottom side of the ring and one or more guides for engaging one or both vertical sides of the support ring 107. An example of an embodiment of a bearing system is shown in more detail in Figures 14A and 14B.

The support structure further comprises a raised support 113a to 113f for supporting each solar collector 103a to 103f above the support ring 107. In this embodiment, each raised support 113a to 113f comprises a truss-like structure 115 comprising upper and lower spaced apart, generally horizontal beam members 117, 119, opposed and spaced apart upright members 121, 123 connected to the upper and lower beam members, one or more cross brace members 125 extending at an angle and between the upper and lower beams and connected thereto, and optional additional stabilizer members 127, 129 extending at an angle from the upper beam member to the lower beam member and positioned outside of the upright members 121, 123. The lower beam 119 of each raised support extends from one side of the ring support 107 to an opposite side thereof and is connected thereto at or near the two positions where the lower beam meets the support ring, e.g. positions 131, 133 shown in Figure 1.

Referring to Figure 2, one or more stabilizer members 135 are provided to stabilize the raised supports in the upright position and to resist rotational movement of the raised member about an axis directed along and positioned close to the lower beam member 119. In this embodiment, each stabilizer member 135 is connected to the raised support at a position above its connecting point to the ring member and extends generally transversely to the

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8UBSTTTUTE SHEET(RULE 2 ^β |

direction of the upper and lower beams. In this embodiment, each stabilizer member is angled downwardly and may be connected to the lower beam member 119 of an adjacent raised support or to some other part of the structure. In other embodiments, a stabilizer may alternatively, or in addition be positioned forward of the raised support. In other embodiments, the lower end of the stabilizer may be connected to any other suitable support mechanism, for example a dedicated support member positioned between opposite sides of the ring support or to the lower beam member, cross brace, or outer stabilizer member of any other raised support.

In this embodiment, each raised support provides a pivotal mounting 139 for pivotally mounting one or more solar collectors 103a to 103f about a longitudinal axis, which may extend generally in the direction of the upper and lower beams 117, 119 of a respective raised support. An actuator 141 may be provided to control the rotational position of the or each solar collector about its rotational axis 139 for elevational solar tracking. Each actuator may comprise any suitable actuator capable of rotating and controlling rotational movement of the or each solar collector. In this particular embodiment, the actuator includes an arm 143 which is connected to the solar collector at a position spaced from the rotational axis 139 and which causes the solar collector to rotate with movement of the arm in a direction generally along its length.

Referring to Figure 1, the support structure further comprises one or more beam members 147, 149 extending between the front portion 150 and a rear portion 151 of the support ring 107 and generally transversely of the lower beams 119 of the raised support

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SUBSTTTUTE SHEET (RULE M)

structure. The support structure shown in Figure 1 includes two such beam members positioned on either side of the support ring. Other embodiments may include any other number of such beams.

The lower beams of the raised structure and the beams 147, 149 transverse thereto assist in providing structural rigidity to the support ring 107.

Referring to Figure 2, the height of the raised structures increases gradually from front 113a to rear 113f so that each solar collector is supported at a slightly different level to an adjacent collector. This assists in reducing the shadowing of one collector by the collector in front of it. However, in other embodiments, each raised structure may have the same height and/or the solar collectors may each be supported at the same level. In other embodiments, the height of one collector relative to an adjacent collector (i.e. a collector in front of it) may be increased above that shown in Figure 2, as required.

Figures 5 to 8 show various views of a support structure according to another embodiment of the present invention. The support structure is similar to that shown in Figures 1 to 4, and like parts are designated by the same reference numerals. The main difference between the support structure shown in Figures 5 to 8 and the former embodiment shown in Figures 1 to 4 is that the bearings for rotatably supporting the support ring are supported on one or more posts 61, 63 which are embedded in a suitable substrate, such as the ground. In this embodiment, the support for each bearing comprises first and second posts 61, 63 one or more of which may include an augur to assist inserting each post into the ground (by rotation thereof) and also to

13 SUBSTITUTESHEET(RULE28)

provide a support surface to help prevent the posts sinking further into the ground once installed. The first post 161 may be installed vertically into the ground and the second post 163 may be installed at an angle thereto and this may increase the lateral stability of the support structure. Each post may be driven into the ground by any desired amount and may provide any desired distance between the ground surface and the support ring and bearings.

Figures 9 to 12 show various views of another support structure according to an embodiment of the present invention. The support structure is similar to that shown in the previous figures and like parts are designated by the same reference numerals. The main difference between the embodiment shown in Figures 9 to 12 and that shown in the previous figures resides in the structure for supporting the ring bearings. In the embodiment shown in Figures 9 to 12, the support for each bearing comprises a pillar 171 upstanding from the ground by a height which is sufficient to allow a person to stand below the support structure. In this particular embodiment, the support structure is supported by the pillars 171 at a height which is sufficient to accommodate a vehicle below the support structure. The support structure may be positioned in a car park or vehicle parking lot. The spaces for each vehicle are indicated by opposed, spaced apart dividing lines 173, 175, for example. The pillars may be arranged to preserve the original number of spaces in the parking lot by not encroaching significantly on the space defined for each vehicle. In the present embodiment, each pillar is positioned either on or close to a line defining a vehicle space.

A guide or housing 177 may be provided for feeding energy collected by the solar collectors to ground, and

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SUBSTTTUtE SHEET (IHJlE Jβ>

thereafter to a suitable point of processing, distribution and/or use. The housing or guide 177 may also be positioned so as not to interfere with the space allocated for vehicles, and in this embodiment is positioned close to, or on one or more lines defining vehicle spaces. In other embodiments, the special guide or housing 177 may be omitted and one or more pillars may provide the means for accommodating one or more fluid conduits, one or more electrical cables and/or one or more optical waveguides for carrying collected energy from the solar collectors.

In this embodiment, a transverse beam member 181 is positioned between adjacent pillars at an elevated position near the top thereof to help prevent lateral movement of the pillars and to increase structural rigidity. The beam members may comprise any suitable members such as I-beams, or may comprise any other suitable structure which has a similar function.

Figure 13 shows an array of support structures positioned in a car park or vehicle parking lot, each of which is similar to that shown in Figures 9 to 12. In addition, an inverter for converting DC electrical current produced by one or more solar collectors into AC current is provided adjacent at least one of the solar collector arrays together with a housing 187 therefor. The inverter may also be positioned above ground at a similar level to the raised support structure, for example as shown in Figure 13. In this particular embodiment, the support 189 for the housing 187 comprises a transverse member which extends between two adjacent support structures.

Figure 14 shows an example of a bearing assembly for rotatably supporting a ring support. The bearing

15 SUBSTITUTE SHEET (RULE 2B)

assembly 201 comprises a base 203, a roller bearing 205 having a rotary shaft 207 which is rotatably mounted in the base 203 and which supports the support ring 209 from its lower surface 211. The bearing assembly further includes one or more rotary bearings 213, 215 which are rotatably mounted to the base for rotation about an axis 217, 219 which may be generally parallel or angled to the sides 221, 223 of the support ring 209. The bearing assembly may comprise one, two or more rotary bearings on one side of the support ring and/or one, two or more rotary bearings on the other side of the support ring.

The support ring may include one or more flanges 225, 227 extending outwardly from a side thereof and below a rotary bearing 213, 215 to assist in preventing upward movement of the support ring relative to the bearing assembly.

The bearing assembly further includes a mounting 229 for mounting the bearing assembly to a suitable substructure, such as a mounting plate, for example shown in the embodiment of Figures 1 to 4, one or more posts, for example as shown in the embodiments of Figures 5 to 8 or one or more pillars as shown for example in the embodiment of Figures 9 to 13.

Figure 15 shows an example of a mechanism for driving rotary movement of the support structure, according to an embodiment of the present invention. Referring to Figure 15, the driving mechanism comprises a capstan 303 which is driven about its rotary axis 305 by a suitable motor 307. The capstan 303 is positioned adjacent the support ring 309 which is supported at spaced intervals by a plurality of bearing assemblies 311, each of which may be

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SUBSTTfUTE SHEET (RULE M)

similar to that shown in Figures 14A and 14B. A cable 315 is connected to the support ring at spaced positions 317, 319 and passes around the outer circumferential surface 321 of the support ring and is looped around the capstan 303. The inventor has found that this mechanism provides sufficient traction between the capstan and cable to rotate the support structure, obviating the need for any more complex mechanisms such as a toothed support ring and motor driven gear wheel engaging the toothed support ring.

Referring to Figure 16A, an embodiment of a ground mounting system 401 for mounting a solar collector according to an embodiment of the present invention comprises an anchor post 403 having opposed ends 405,407, one end being for insertion into the ground to form a support for a solar collector 409. The upper end 405 may include a pivotal mounting for pivotally mounting the solar collector for rotation about a longitudinal axis 411 of the collector. The post may also provide a support for an actuator 413 for tiling the solar collector.

In some embodiments, the mounting system further includes a lateral force support 415 coupled to the post and capable of being positioned above the lower end 407 of the post to provide an anchor for resisting lateral force. In one embodiment, the lateral force support assembly comprises one or more flanges, vanes or other structure extending transversely away from the longitudinal axis of the post for engaging the ground material, and which may, for example, be positioned below, e.g. just below the ground surface 419 to reduce or prevent lateral motion of the post. The lateral support 415 may be connected to the post in such a way that the connection prevents relative vertical motion between the support 415 and the post. Embodiments of the lateral support

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SU8STTTUTE SHEET (RULE 2β>

are shown in more detail in Figures 16A and 16B. Referring to Figure 16A, the support comprises a collar 421 having a through hole 423 for receiving a post, and a plurality of vanes 417 extending outwardly from and positioned about the collar. In this example, the support has four vanes positioned at 90 degree intervals for resisting lateral force applied in two orthogonal directions. The side edges of the vanes taper inwardly towards the lower end to facilitate insertion into the ground. In other embodiments, the support may have any other number of vanes of the same or different shape to those of Figure 16A.

Figure 16B shows another embodiment of a lateral support 427, comprising an assembly of first and second lower ^λλ L" shaped or angled pieces 429, 431, positioned either side of the post, each having a vertical and horizontal flange 433, 435. The assembly also includes third and fourth L-shaped sections 437, 439, having vertical and horizontal flanges 441, 443, and which are also positioned either side of the post but transversely of the first and second flanges. The vertical flanges are slotted to register with the vertical flanges of the first and second sections 429, 431, which may also have slots 445 for receiving the vertical flanges of the third and fourth sections. The vertical flanges resist lateral movement, while the horizontal flanges resist vertical movement and assist in supporting the load of the solar collector. Each lateral support may have an aperture 447 through a side thereof for receiving a fastener for securing the support to the post.

In some embodiments, the post may be provided with an auger 449 or similar device at the lower end thereof and which may be rigidly affixed to the anchor post. The auger tip may have a relatively low pitch to resist vertical

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motion or displacement of the post, and assist in supporting the load of the solar collector. The anchor post may be augured into the ground and/or a hole dug and the post assembly buried and back filled. The anchor post may be formed of any suitable material and may have any suitable cross-sectional geometry. In some embodiments, the post comprises solid wood and has a square or round structural section which may be hollow. In other embodiments, the post may comprise a tubular construction formed of any suitable material such as a metal, e.g. aluminum or steel or other similar structural material. In the embodiment of Figure 16A, the support structure has two support posts for supporting a solar collector, spaced apart along the length of the collector, although in other embodiments, any other number of posts may be used to support a solar collector. The posts may support the solar collector at any height above ground level. In the arrangement of Figure 16A, all solar collectors are positioned at substantially the same height, although in other embodiments, the solar collectors may be supported at different heights relative to each other .

In some embodiments, a surface mounting system may be provided comprising an arrangement of interconnected structural sections, examples of which are shown in Figures 17 and 18. Referring to Figure 17, a mounting system 501 comprises first and second mounting structures 503, 505, each having an upright section 507, having upper and lower ends, a first horizontal structure 509 connected to the lower end of the upright section 507, and having opposed ends 511, 513, and second and third horizontal structures each connected, at a mid point thereof, in this example, to a respective opposed end 511, 513 of the first horizontal structure, and extending transversely thereof.

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8UB8TTTUTE SHEET (RULE 2β)

The structural sections may be interconnected using any suitable technique, for example a technique that does not involve welding or metal fusing. For example, the structural sections may be connected together using clamps or other mechanical means, connectors or couplers 515. The structural horizontal sections may all be similar to one another (e.g. in length, width and/or geometry) . The connectors may be similar to one another. The system shown in Figure 17 may be suitable for supporting the solar collector on a surface such as a building roof 515 with limited point load support capability.

In some embodiments, one or more of the structural sections may comprise a tubular section. The tubular sections may have any desired cross-sectional geometry such as circular or square or rectangular.

The mounting system may include one or more pads 519 having an area which is greater than the cross- sectional area of the structural sections, for example, which may serve to spread the load to more uniformly distribute weight and wind load to the support structure below which may comprise the membrane of a building roof.

Referring to Figure 18, another embodiment of a support structure 531 for a solar collector comprises first and second mounting structures 533, 535, spaced apart in the longitudinal direction of the solar collector 537. Each mounting structure comprises an upright member 539 having upper and lower ends, and a horizontal member 541 connected to the lower end of the upright member and extending in a direction transverse to the longitudinal axis of the solar collector, and either side of the upright member. The upper end of the upright member may include a pivotal mounting for

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rotatably supporting the solar collector about a longitudinal axis. A connector 543 is provided to join the upright member to the horizontal member, and may comprise receptacles for receiving the end of the upright member and the horizontal member. The horizontal member may comprise a single section or first and second sections 545, 547 extending in opposite directions from the connector 543. In some embodiments, the mounting system may include one or more internal and/or external joiner sections 549, 551 for connecting sections, of the tubular support sections, e.g. sections 553, using any suitable fastening system, for example bolts, rivets, screws or other suitable fasteners.

In some embodiments, the mounting system may include clamps which may be formed by stamping from a material such as tough steel or stainless steel, where the ultimate strength of the material is higher, e.g. substantially higher, than the yield strength.

Figure 19 shows a graph of the variation of solar radiation with month of the year for different surface orientations.

Referring to Figures 2OA and 2OB a mounting system 601 is provided for mounting a plurality of collectors 603 in a stacked angled array. The mounting system may be arranged such that the collectors are stacked at an angle approximately equal to the latitude location on the planet and track the sun vertically in the sky and in addition also track azimuth. This may have the effect of capturing up to 35% more direct solar radiation than an east-west axis single axis tracking system, as for example shown in the graph of Figure 19.

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WSTTTUTE SHEET (RULE 8β|

Referring to Figure 2OA, the stacked angular mounting system may comprise a rotary support 605 for enabling the mounting system to rotate about the vertical axis (i.e. the azimuth axis 607 shown in the figure) . The support also enables one or more reflectors of the solar collectors to rotate to different angles of inclination, e.g. about axis 609 for the top reflector, for example.

In this embodiment, the support structure comprises first and second spaced apart support members 611, 613 which slope at an angle to the vertical, and first and second support arms 615, 617, positioned behind and connected to the support members, and which slope in the opposite direction to the support members . The support members and/or support arms may comprise elongate tubular or solid members, having any cross-sectional geometry, for example circular, square or rectangular. The support members and/or arms may each be formed of a plurality of sections, joined together by any suitable means, for example brackets. The support members each have a pivotal mounting bracket for pivotally mounting each solar collector on the support members at spaced intervals along its length. Each solar collector has an actuator associated therewith for controlling the position of the solar collector about its longitudinal axis (e.g. 609). The actuator may be connected to a support member 611, for example by means of bracket 623, or other suitable mounting, and includes an actuator arm 625 connected to the solar collector at a suitable position spaced from the axis of rotation. Each actuator may be arranged to control the orientation of a respective collector independently of the other actuators.

In this embodiment, the support structure is mounted for azimuth rotation on a circular support track

629. An example of the rotary support mechanism is shown in Figure 2OB. The support track 629 has a side portion and spaced apart upper and lower portions 633, 635 which together provide a generally "C" shaped cross sectional geometry. A rotary bearing system 635 mounted to the support structure 601 engages with and supports the support structure on the track 629. In the embodiment, the bearing system comprises upper and lower bearing members 637, 639, for example roller bearings, which are rotatably mounted on the support structure and engage upper and lower portions 631, 633 of the track within the groove or slot formed in the side thereof. In this embodiment, a drive mechanism 641 is provided to drive rotation of the support structure. The drive mechanism comprises a motor 643, mounted to the support structure 601 by a suitable mounting structure 645, an optional gear mechanism 647, a winch 648, (e.g. windlass winch) and cable 649, which extends e.g. partially, around the track 629 and in connected thereto at spaced apart positions with the drive mechanism between, and may be disposed within a guide groove 651. The cable may be looped about the winch, so that the tension in the cable forces the cable against the winch, increasing the frictional force between the two and preventing slippage, in a similar manner to the embodiment of Figure 15. In operation, the motor rotates the winch through the optional gear mechanism, and as the winch draws in the cable in one direction on the other, the support structure rotates. In other embodiments, the drive mechanism may be mounted on the track. Other embodiments may comprise any other suitable rotation system.

In some embodiments, the azimuth angle is controlled by a system controller 655. The azimuth angle may be sensed by a sensor 657, e.g. by an electric compass or other means, and fed back to the system controller 655.

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In some embodiments, the azimuth angle is fed back to a system controller via a rotary position inducer.

In some embodiments, the mounting system includes a roller channel track which may be suitably secured to a lower support. The lower support may for example comprise a concrete or other structural slab, or any other support substrate .

In some embodiments, a screen or substrate, e.g. screen 650 (Figures 2OA and 21) may be provided on the support structure for any suitable purpose. For example, the screen may be used to provide information, such as advertisement (s) , which may be applied to the screen or substrate. Alternatively, the screen may be used to receive a projected image.

In some embodiments, the rolled channel track is attached to one or more posts for a ground-mounted system, and an example of such an arrangement is shown in Figure 21. In this embodiment, a circular track 629 for rotatably supporting the solar collector support structure 601 is mounted on a number of posts 661 upstanding from the ground and spaced apart circumferentially about the track. The posts may either rest on the surface of the ground or be embedded in the ground. The ground mounting posts may include any one or more features of the anchoring posts described above.

In some embodiments, a bracket may be provided and may serve both to provide the pivot support and actuator attachment means, and the bracket may be clamped or otherwise connected to the structural support sections (e.g. tubes 611, 613, 615, 617) . A stamped or molded bracket may

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allow the actuator to be mounted beside rather than through the structural member.

In some embodiments, a two axis solar collector mounting system comprises one or more parts from the embodiments shown in Figure 2OA, for example, any one or more of the motor drive and/or support posts and/or clamping system and/or pivot clamp and/or joiner extrusion, to form a modular flexible "solar lego" system of a solar collector mounting.

Figure 21 shows another embodiment of a solar collector support structure 701, which is capable of supporting a plurality of solar collectors 703. The support structure comprises a horizontally extending frame 705 having opposed longitudinal members 707, 709 spaced apart by a plurality of transverse members 711. The structure includes respective first and second upright members 713, 715 for supporting a solar collector, upstanding from the frame, and each having a pivotal mounting for pivotally mounting the collector thereto for rotation about a longitudinal axis 717 thereof. In this embodiment, the upright members may be supported by the frame at positions at or near at least one of the longitudinal members and the transverse members. Each collector has an actuator 719 associated therewith for controlling the tilt angle of the collector about its longitudinal axis.

The frame is supported on a rotary support 725 for azimuth rotation, to enable all collectors mounted on the support structure to be rotated together by the same mechanism. This embodiment is particularly suitable for mounting the collectors at the same or similar height (s), for example, where a low profile is required or desirable.

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The azimuth drive system may be similar to that described above with reference to Figure 2OA and 2OB, or may comprise any other drive mechanism.

Any aspect or embodiment of the present invention may comprise any one or more features disclosed herein in combination with any one or more features disclosed herein. In any aspects or embodiments of the invention, any one or more features may be omitted altogether or substituted by an equivalent or variant thereof.

Other aspects and embodiments of the present invention may comprise any one or more features disposed therein in combination with any one or more features disclosed in the applicants co-pending US Patent Application Serial No. 60/786,362 filed on 28 ^th March, 2006 entitled SOLAR COLLECTOR, attorney reference 51159-8, and in the applicant's co-pending PCT application filed on 28 ^th March, 2007, entitled "Solar Collector", attorney docket number 511 59-14, the entire contents of which are incorporated herein by reference.

Numerous modifications to the embodiments described above will be apparent to those skilled in the art.

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