EP2588790A1

EP2588790A1 - Bearing assembly for a solar collector system

Info

Publication number: EP2588790A1
Application number: EP11801366.3A
Authority: EP
Inventors: Zachary Marten; Vikas Kotagiri
Original assignee: Magna International Inc
Current assignee: Magna International Inc
Priority date: 2010-07-01
Filing date: 2011-06-29
Publication date: 2013-05-08
Also published as: US20130152915A1; CA2802104A1; EP2588790A4; MX2012015275A; WO2012003235A1; BR112012033459A2

Abstract

A solar collector system is provided including a bearing assembly comprising a plurality of wheels or rollers for rollingly engaging a large-diameter support element. Rotation of the large-diameter support element supports tracking of the position of the sun relative to the solar collector system. The bearing assembly may be pre-assembled to the large-diameter support element before the solar collector system leaves the factory, thereby facilitating assembly of the solar collector system in the field, even under adverse conditions.

Description

BEARING ASSEMBLY FOR A SOLAR COLLECTOR SYSTEM

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. provisional application serial number 61/360,612 filed July 1, 2010, the entire disclosure of the application being considered part of the disclosure of this application, and hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

[0002] The instant invention relates generally to a bearing assembly for a solar collector system, and more particularly to a low speed bearing assembly for a solar collector system based on a large diameter structural support cylinder.

2. Description of the Prior Art

[0003] Systems that are designed to convert solar radiation or "solar energy" into heat or electricity have long been suggested as an attractive alternative to conventional energy sources such as crude oil, natural gas and the like. In particular, solar energy is known to be a vast and largely untapped renewable energy source that can be converted into a usable form without releasing harmful emissions into the environment. Unfortunately, high capital costs combined with low energy conversion efficiencies have thus far limited the adoption of solar collector systems to mostly small-scale installations and "off-grid" or niche applications.

[0004] More recently, considerable effort has been directed toward developing improved types of solar collectors to gather solar energy and concentrate the solar energy into a relatively small area to thereby achieve high temperatures. For instance, a reflective surface is used to concentrate solar radiation from a relatively large area onto a relatively small target or collector surface. One specific type of system utilizes long, reflective trough structures to concentrate the solar radiation onto high gain solar panels miming along the top of the trough structure. Alternatively, a parabolic dish reflector is used.

[0005] The efficiency of a reflector type solar collector system is greatly increased by utilizing a movable solar collector that tracks the movement of the sun across the sky. In this way, the solar collector can be effectively aimed at the sun such that the reflected solar radiation is focused continuously onto the collector surface. Unfortunately, the methods and apparatus for supporting and aiming solar collectors toward the sun are rather crude and simple. For example, typically the solar collector is mounted to an axle or support rod that is journaled into a bearing or bushing structure, such that the supported solar collector can be rotated to point the reflective surface thereof directly toward the sun. This-type of apparatus for supporting the solar collector is wrought with many problems. Specifically, it is extremely difficult to install such a type of system in such a manner that the bearing structures and the support rods are in precise alignment. This is extremely critical when the solar collector is quite large and the bearing structures are a considerable distance apart, such as for instance the case of a solar collector with trough-shaped reflector elements that may be up to 25 feet in length with the collector being supported only at the outer ends by journaling the support rods into respective bearing structures. Of course, even if the collector system is installed with the bearing structures precisely aligned to receive the support rods, problems still arise due to an uneven shifting of the support pylons along the length of the collector system. Such a movement and shifting of the pylons results in a misalignment of the bearing structures.

[0006] Hutchison in United States patent 4,306,540 proposes an improved solar collector mounting and support apparatus. The apparatus includes a support axle for the solar collector, which has a ball at one end that is carried within a cylindrical sleeve in the solar collector to support the weight of the collector. At an opposite end of the solar collector, a support pylon assembly is provided in which a pair of lower bolts passes through a rectangular body of the support pylon, parallel to the axis of rotation of the support axle. A roller is carried on each lower bolt, the rollers being positioned to support the axle when the axle is positioned on top of the support pylon. A third roller is provided on an upper bolt, which passes through holes that are defined in one end of each of a pair of curved retaining arms. An opposite end of each one of the retaining arms is pivotally carried on one of the pair of lower bolts. The retaining assembly, including the third roller, upper bolt and pair of curved retaining arms, prevents the axle from being lifted accidentally from the pylon, such as for example by a windstorm.

[0007] In order to mount the solar collector, first the support axle is positioned on the rollers on top of the support pylon, and the curved retaining arms are pivoted about the lower bolts. The holes in the one end of each of the pair of retaining arms are aligned for receiving the upper bolt, and the upper bolt and third roller are assembled to the retaining arms. In particular, the third roller is "sandwiched" between the retaining an-ns and is held in place by the upper bolt. A fastener is then tightened onto the upper bolt, in order to hold the retaining assembly together. Unfortunately, the retaining assembly can be assembled together only after the solar collector has been placed on top of the rollers. Hence, the task of assembling the retaining assembly must be performed in the field, often under adverse weather conditions. For instance, windy weather may result in shifting of the axle before the retaining assembly can be fully assembled, and may frustrate attempts to align the holes in the retaining arms, insert the upper bolt, and simultaneously position the third roller on the bolt between the retaining arms. Similarly, cold temperatures may make it difficult to handle and manipulate the multiple, small parts of the retaining assembly. The need to assemble the retaining assembly in the field results in increased installation costs and delays. [0008] Accordingly, it would be advantageous to provide a solar collector system having a mounting and support apparatus that overcomes at least some of the above- mentioned limitations.

SUMMARY OF THE INVENTION

[0009] In accordance with an aspect of the invention there is provided a solar collector system, comprising: a movable solar collector surface; a support element coupled to the solar collector surface, the support element having a length and having an outer surface that defines a circle in a cross section taken in a plane normal to the length, the support element being rotatable about a longitudinal axis defined along the length thereof; a housing assembly having a mounting end and a bearing end, the mounting end comprising a mounting structure for fixedly securing the housing assembly to a base element, the bearing end defining an opening for receiving the support element when the housing assembly and the support element are coupled together such that the housing assembly at least partially encircles a portion of the outer surface of the support element, the encircled portion of the outer surface defining a bearing surface of the support element; a pair of first wheels mounted to the bearing end of the housing assembly, each first wheel of the pair of first wheels disposed adjacent to the opening and protruding into the opening for contacting a portion of the bearing surface that faces toward the mounting end of the housing assembly when the housing assembly and the support element are coupled together; and, at least one second wheel mounted to the bearing end of the housing assembly, the at least one second wheel disposed adjacent to the opening and protruding into the opening for contacting a portion of the bearing surface that faces away from the mounting end of the housing assembly when the housing assembly and the support element are coupled together, wherein the housing assembly and the support element are coupleable together prior to securing the housing assembly to the base element. [0010] In accordance with an aspect of the invention there is provided a solar collector system, comprising: a movable solar collector surface; a cylindrical support element coupled to the solar collector surface, the cylindrical support element having an outer surface extending along a length thereof and being rotatable about a longitudinal axis that is defined along said length; a housing assembly comprising first and second housing elements defining a central opening therebetween when the housing assembly is in an assembled condition, the central opening sized for receiving the cylindrical support element when the housing assembly and the cylindrical support element are coupled together, the housing assembly having a mounting end and a retaining end disposed on opposite sides of the central opening, the mounting end comprising a mounting structure for fixedly securing the housing assembly to a base element and the retaining end comprising a retaining element for detachably coupling together the first and second housing elements at the retaining end of the housing assembly; a pair of load bearing wheels mounted one each to the first and second housing elements and protruding into the central opening, for rollingly engaging a first portion of the outer surface of the cylindrical support element that faces toward the mounting end of the housing assembly when the housing assembly and the cylindrical support element are coupled together; and, a pair of counter load wheels mounted one each to the first and second housing elements and protruding into the central opening, for rollingly engaging a second portion of the outer surface of the cylindrical support element that faces toward the retaining end of the housing assembly when the housing assembly and the cylindrical support element are coupled together, wherein the housing assembly and the cylindrical support element are coupleable together prior to securing the housing assembly to the base element.

[0011] In accordance with an aspect of the invention there is provided a solar collector system, comprising: a movable solar collector surface; a cylindrical support element coupled to the solar collector surface, the cylindrical support element having an outer surface extending along a length thereof and being rotatable about a longitudinal axis defined along said length; a housing assembly comprising a plurality of wheels, the housing assembly coupled to the cylindrical support element such that the cylindrical support element is disposed between a first group of the plurality of wheels and a second group of the plurality of wheels, the housing assembly comprising a mounting structure for fixedly securing the housing assembly to a base element, the mounting structure disposed on the housing assembly relative to the plurality of wheels such that when the housing assembly is fixedly secured to the base element via the mounting structure, the first group of the plurality of wheels rollingly engages the outer surface of the cylindrical support element and bears the weight of the cylindrical support element and the second group of the plurality of wheels acts as counter load wheels, wherein the housing assembly and the cylindrical support element are coupleable together prior to securing the housing assembly to the base element.

[0012] In accordance with an aspect of the invention there is provided a method, comprising: providing a solar collector assembly comprising a solar collector surface that is coupled to a cylindrical support element, the cylindrical support element having an outer surface and a length; providing a housing assembly having a plurality of wheels mounted thereto including a pair of load bearing wheels and at least a counter load wheel, the housing assembly having a mounting structure for fixedly securing the housing assembly to a base element; coupling the housing assembly to the cylindrical support element such that the cylindrical support element is disposed between the pair of load bearing wheels and the at least a counter load wheel; and, fixedly securing the coupled together housing assembly and solar collector assembly to a base element via the mounting structure of the housing assembly and a complementary mounting structure of the base element, such that the pair of load bearing wheels rollingly engage the outer surface of the cylindrical support element and bear the weight of the cylindrical support element.

[0013] In accordance with an aspect of the invention there is provided a solar collector system, comprising: a movable solar collector surface; a cylindrical support element coupled to the solar collector surface, the cylindrical support element having an outer surface extending along a length thereof and being rotatable about a longitudinal axis defined along said length; a housing assembly comprising a plurality of spherical rollers, the housing assembly coupled to the cylindrical support element such that the cylindrical support element is disposed between a first group of the plurality of spherical rollers and a second group of the plurality of spherical rollers, the housing assembly comprising a mounting structure for fixedly securing the housing assembly to a base element, the mounting structure disposed on the housing assembly relative to the plurality of spherical rollers such that when the housing assembly is fixedly secured to the base element via the mounting structure, the first group of the plurality of spherical rollers rollingly engages the outer surface of the cylindrical support element and bears the weight of the cylindrical support element and the second group of the plurality of spherical rollers acts as counter load rollers, wherein the housing assembly and the cylindrical support element are coupleable together prior to securing the housing assembly to the base element.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Other advantages of the present invention will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

[0015] FIG. 1 is an exploded perspective view of a solar collector assembly according to an embodiment of the instant invention; [0016] FIG. 2 shows a pair of housing assemblies coupled to the cylindrical support element of the solar collector system of FIG. 1 , according to an embodiment of the instant invention;

[0017] FIG. 3 is an exploded perspective view of another solar collector assembly according to an embodiment of the instant invention;

[0018] FIG. 4 shows a pair of housing assemblies coupled to the cylindrical support element of the solar collector system of FIG. 3, according to an embodiment of the instant invention;

[0019] FIG. 5 is an enlarged perspective view showing a housing assembly coupled to the cylindrical support element of the solar collector system of FIG. 1 or FIG. 3, according to an embodiment of the instant invention;

[0020] FIG. 6 is a cross-sectional view of a housing assembly according to an embodiment of the instant invention; and,

[0021] FIG. 7 is a simplified flow diagram for a method of installing a solar collector assembly according to an embodiment of the instant invention.

DETAILED DESCRIPTION OF THE ENABLING EMBODIMENTS

[0022] The following description is presented to enable a person skilled in the art to make and use the invention, and is provided in the context of a particular application and its requirements. Various modifications to the disclosed embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the scope of the invention. Thus, the present invention is not intended to be limited to the embodiments disclosed, but is to be accorded the widest scope consistent with the principles and features disclosed herein.

[0023] Referring to FIG. 1 , shown is an exploded perspective view of a solar collector assembly 100 according to an embodiment of the instant invention. In this specific and non- limiting example the collector assembly 100 is a dual trough solar energy concentrator or collector, having two optical apertures 102a and 102b. The optical apertures 102 admit incident sunlight onto reflector panels 104. In particular, four reflector panels 104 are grouped into two pairs of opposing panels that are arranged in a substantially edge-to-edge fashion. The top surface of each reflector panel 104 is, by way of a specific and non-limiting example, covered with a thin durable metallic coating, which is encased in oxide layers to ensure high durability and structural rigidity. Optionally, the top surface of each reflector panel 104 is fabricated using another suitable reflective material. Further optionally, struts and/or other reinforcing members are mounted to the lower surfaces of the reflector panels 104, resulting in a very durable yet lightweight structure.

[0024] Incident sunlight that enters collector assembly 100 through the optical apertures 102 impinges upon one of the reflector panels 104 and is directed toward a region slightly above a top edge of the opposing reflector panel 104. Solar receivers 106 are mounted in a vertical orientation near the top edges of the reflector panels 104 for collecting the reflected solar radiation. In the instant example the solar receivers 106 are High Gain Solar (HGS) panels, which include a not illustrated backing plate, silicon cells, encapsulant, glass cover plate and junction box. The solar receivers 106 further include a not illustrated metal heat sink, which enables efficient convection cooling with natural airflow.

Optionally, the solar receivers 106 include a quick-connect feature for rapid installation onto the solar collector 100 and easy maintenance.

[0025] The reflector panels 104 are supported at opposite ends thereof using V- shaped support elements 108. Each V-shaped support element 108 supports two reflector panels 104, so as to define one of the two troughs of the collector assembly 100. The V- shaped support elements 108 are mounted to support rings 110 via projections 112. Each support ring 110 is fixedly mounted to a cylindrical support element 114, such that rotational motion of the cylindrical support element 114 about a longitudinal axis A is transferred to the reflector panels 104 via the support rings 110, projections 112 and V- shaped support elements 108. The cylindrical support element 114 is, by way of a specific and non-limiting example, a large diameter structural support cylinder fabricated from mild steel. A typical diameter of the cylindrical support element 114 is approximately eight inches.

[0026] Controllably rotating the cylindrical support element 114 causes the reflector panels 104 to move, thereby allowing the collector assembly 100 to track the movement of the sun across the sky over the course of a day. To this end, the cylindrical support element 114 is journaled into a bearing end of each one of a plurality of housing assemblies 116. The bearing end of each housing assembly 116 includes a plurality of wheels 118, which are mounted adjacent to and project into a central opening of the bearing end so as to support the cylindrical support element 114, while at the same time allowing the cylindrical support element to rotate about the longitudinal axis A. The wheels 118 are fabricated from a suitable material, such as for instance nylon. Further, the wheels 118 include an axle and bearing assembly for mounting the wheels to the housing assembly 116. Of course, the solar collector assembly 100 also includes a not illustrated drive mechanism and a not illustrated controller for controllably rotating the cylindrical support element 114.

Optionally, spherical-shaped rollers are employed in place of the wheels 118.

[0027] Referring still to FIG. 1, each housing assembly 116 further includes a mounting end 120 having a mounting structure for fixedly securing the housing assembly to a base element, such as for instance one of the pylons 122. In the instant example four housing assemblies 116 are used to carry the cylindrical support element 114. Of course, the number of housing assemblies 116 that is required for a particular application depends upon a number of factors. Determining a suitable number of housing assemblies 116 for a particular application is considered to be within the capabilities of a person having ordinary skill in the art.

[0028] The collector assembly 100 is optionally expanded by mechanically coupling additional sets of reflector panels 104 to the cylindrical support element 114. Adjacent sets of reflector panels 104 are supported using V-shaped support elements 108 that are disposed within a space between the respective ends thereof. A typical solar collector array may be approximately 25 feet in length. Typically, an array of collector assemblies shares a common drive mechanism and tracking controller hardware. For instance, four collector assemblies coupled together are driven simultaneously using a single drive unit disposed in the center of the array.

[0029] FIG. 2 is a partial bottom view showing a pair of housing assemblies 116 coupled to the cylindrical support element 114 of the system of FIG. 1. Two sets of reflector panels 104a and 104b are shown coupled together in FIG. 2, with V-shaped support elements 108 disposed between the ends of the reflector panels 104a and the ends of the reflector panels 104b. As such, support ring 110 carries both sets of reflector panels 104a and 104b, and rotational movement of the cylindrical support element is transferred to both sets of reflector panels 104a and 104b. One housing assembly 116 is disposed adjacent to each side of the support ring 110. As is described in greater detail below, the plurality of wheels 118 of each housing assembly 116 rollingly engages an outer surface of the cylindrical support element 114. Also shown in FIG. 2, the mounting end 120 of each housing assembly is oriented for being fixedly secured to a base element.

[0030] Referring to FIG. 3, shown is an exploded perspective view of a solar collector assembly 300 according to an embodiment of the instant invention. In this specific and non- limiting example the collector assembly 300 is a single trough solar energy concentrator or collector, having one optical aperture 302. The optical aperture 302 admits incident sunlight onto reflector panels 104. In particular, two reflector panels 104 are grouped into a pair of opposing panels that are arranged in a substantially edge-to-edge fashion. The top surface of each reflector panel 104 is, by way of a specific and non- limiting example, covered with a thin durable metallic coating, which is encased in oxide layers to ensure-high durability and structural rigidity. Optionally, the top surface of each reflector panel 104 is fabricated using another suitable reflective material. Further optionally, struts and/or other reinforcing members are mounted to the lower surfaces of the reflector panels 104, resulting in a very durable yet lightweight structure.

[0031] Incident sunlight that enters collector assembly 300 through the optical aperture 302 impinges upon one of the reflector panels 104 and is directed toward a region slightly above a top edge of the opposing reflector panel 104. Solar receivers 106 are mounted in a vertical orientation near the top edges of the reflector panels 104 for collecting the reflected solar radiation. In the instant example, the solar receivers 106 are High Gain Solar (HGS) panels, which include a not illustrated backing plate, silicon cells, encapsulant, glass cover plate and junction box. The solar receivers 106 further include a not illustrated metal heat sink, which enables efficient convection cooling with natural airflow.

Optionally, the solar receivers 106 include a quick-connect feature for rapid installation onto the solar collector 300 and easy maintenance.

[0032] The reflector panels 104 are supported at opposite ends thereof using V- shaped support elements 108. Each V-shaped support element 108 supports two reflector panels 104, so as to define the trough of the collector assembly 300. The V-shaped support elements 108 are mounted to support rings 110 via projections 112. Each support ring 110 is fixedly mounted to a cylindrical support element 114, such that rotational motion of the cylindrical support element 114 about a longitudinal axis A is transferred to the reflector panels 104 via the support rings 110, projections 112 and V-shaped support elements 108. The cylindrical support element 114 is, by way of a specific and non- limiting example, a large diameter structural support cylinder fabricated from mild steel. A typical diameter of the cylindrical support element 114 is approximately eight inches.

[0033] Controllably rotating the cylindrical support element 114 causes the reflector panels 104 to move, thereby allowing the collector assembly 300 to track the movement of the sun across the sky over the course of a day. To this end, the cylindrical support element 114 is journaled into a bearing end of each one of a plurality of housing assemblies 116. The bearing end of each housing assembly 116 includes a plurality of wheels 118, which are mounted adjacent to and project into a central opening of the bearing end so as to support the cylindrical support element 114, while at the same time allowing the cylindrical support element to rotate about the longitudinal axis A. The wheels 118 are fabricated from a suitable material, such as for instance nylon. Further, the wheels 118 include an axle and bearing assembly for mounting the wheels to the housing assembly 116. Of course, the solar collector assembly 300 also includes a not illustrated drive mechanism and a not illustrated controller for controllably rotating the cylindrical support element 114.

Optionally, spherical-shaped rollers are employed in place of the wheels 118.

[0034] Referring still to FIG. 3, each housing assembly 116 further includes a mounting end 120 having a mounting structure for fixedly securing the housing assembly to a base element, such as for instance one of the pylons 122. In the instant example four housing assemblies 116 are used to carry the cylindrical support element 114. Of course, the number of housing assemblies 116 that is required for a particular application depends upon a number of factors. Determining a suitable number of housing assemblies 116 for a particular application is considered to be within the capabilities of a person having ordinary skill in the art.

13

12 [0035] The collector assembly 300 is optionally expanded by mechanically coupling additional sets of reflector panels 104 to the cylindrical support element 114. Adjacent sets of reflector panels 104 are supported using V-shaped support elements 108 that are disposed within a space between the respective ends thereof. A typical solar collector array may be approximately 25 feet in length. Typically, an array of collector assemblies shares a common drive mechanism and tracking controller hardware. For instance, four collector assemblies coupled together are driven simultaneously using a single drive unit disposed in the center of the array.

[0036] FIG. 4 is a partial bottom view showing a pair of housing assemblies 116 coupled to the cylindrical support element 114 of the system of FIG. 3. Two sets of reflector panels 104a and 104b are shown coupled together in an end-to-end fashion, with V-shaped support elements 108 disposed between the ends of the reflector panels 104a and the ends of the reflector panels 104b. As such, support ring 110 carries both sets of reflector panels 104a and 104b, and rotational movement of the cylindrical support element is transferred to both sets of reflector panels 104a and 104b. One housing assembly 116 is disposed adjacent to each side of the support ring 110. As is described in greater detail below, the plurality of wheels 118 of each housing assembly 116 rollingly engages an outer surface of the cylindrical support element 114. Also shown in FIG. 4, the mounting end 120 of each housing assembly is oriented for being fixedly secured to a base element.

[0037] FIG. 5 is an enlarged perspective view showing a housing assembly 116 coupled to the cylindrical support element 114 of the system of FIG. 1 or FIG. 3. FIG. 6 is a cross-sectional view of the housing assembly 116 coupled to the cylindrical support element 114, taken in a plane that passes through the plurality of wheels 118. With reference now to FIGS. 5 and 6, the housing assembly 116 comprises first and second housing elements 200a and 200b, which define a central opening 202 therebetween when the housing assembly 116 is in an assembled condition. The central opening 202 is sized for receiving the cylindrical support element 114 when the housing assembly 116 and the cylindrical support element 114 are coupled together. The mounting end 120 and a retaining end 204 are defined on opposite sides of the central opening 202. The mounting end comprises a mounting structure 206 that is disposed between the first and second housing elements 200a and 202b. In particular, the mounting structure 206 is for mating with a not illustrated complementary mounting structure of a base element, such as for instance the pylon 122 in FIG. 1 or FIG. 3. The retaining end 204 comprises a retaining element, such as for instance bolt 208 or another suitable fastener, for detachably coupling together the first and second housing elements 200a and 200b at the retaining end 204 of the housing assembly 116.

[0038] Each one of the first and second housing elements 200a and 200b includes a mounting structure for retaining an axel 210a of a load bearing wheel 118a and a mounting structure for retaining an axel 210b of a counter load wheel 118b. When the housing assembly 116 is in an assembled condition and is coupled to the cylindrical support element 114, and when the mounting structure 206 is mated with a complementary mounting structure of a base element, two load bearing wheels 118a are disposed below the cylindrical support element 114 and two counter load wheels 118b are disposed above the cylindrical support element 114. A portion of the outer surface of the cylindrical support element 114 that is encircled by the housing assembly 116 defines a bearing surface, upon which the wheels 118a and 118b rollingly engage the cylindrical support element. As is shown in FIGS. 5 and 6, the load bearing wheels 118a are normally in contact with the bearing surface of the cylindrical support element 114 and the counter load wheels 118b are normally out of contact with the bearing surface of the cylindrical support element 114. The resulting small gap between the counter load wheels 118b and the cylindrical support element 114 supports axial movement of the cylindrical support element 114 relative to the housing assembly 116, so as to allow for thermal expansion and contraction of the cylindrical support element 114, etc. When the cylindrical support element 114 shifts upward, such as for instance during windy weather etc., the counter load wheels 118b rollingly engage the bearing surface of the cylindrical support element and thereby limit its travel.

[0039] As is shown most clearly in FIG. 6, the two load bearing wheels 118a and the two counter load wheels 118b are arranged in a substantially square configuration within the plane of the cross section. Of course, different wheel configurations are also envisaged. For instance, the load bearing wheels 118a may be placed within a range of angles between about 25° and about 65° relative to the line B-B in FIG. 4. Optionally, a single counter load wheel 118b is provided. Optionally, the wheels are mounted to the housing assembly 116 via an adjustable mechanism, such that the extent to which the wheels project into the central opening 202 is adjustable. For instance, during cold weather the wheels may be advanced further into the central opening and during hot weather the wheels may be withdrawn slightly from the central opening, so as to compensate for thermal contraction and expansion of the cylindrical support element 114. Further optionally, a diameter of the load bearing wheels 118a is larger than a diameter of the counter load wheels 118b. Typically, the diameter of the load bearing wheels 118a is less than 50% of the diameter of the cylindrical support element 114. Further, the load bearing wheels 118a and the counter load wheels 118b are mounted to the housing assembly absent a drive mechanism for driving rotation of the cylindrical support element 114.

[0040] As is shown in FIGS. 5 and 6, the housing assembly 116 and the cylindrical support element 114 are coupleable together prior to securing the housing assembly 116 to a base element, such as for instance the pylon 122 in FIG. 1 or FIG. 3. In particular, the first and second housing elements 200a and 200b may be coupled together, with the cylindrical support element accommodated within the central opening 202 that is formed therebetween, during manufacturing of the collector assembly 100. Accordingly, the collector assembly 100 may be shipped from the manufacturer in a pre-assembled condition, such that installation of the assembly 100 requires only securing the mounting structure 206 of each housing assembly 116 to a complementary mounting structure of the base element.

Installation of the collector assembly 100 is simplified, such that the time that is required to install each assembly 100 is reduced and such that installation may be performed under less than ideal weather conditions.

[0041] Referring now to FIG. 7, shown is a simplified flow diagram for a method of installing a solar collector assembly according to an embodiment of the instant invention. At 700 a solar collector assembly is provided, the solar collector assembly comprising a solar collector surface that is coupled to a cylindrical support element, the cylindrical support element having an outer surface and a length. At 702 a housing assembly is provided, the housing assembly having a plurality of wheels mounted thereto including a pair of load bearing wheels and at least a counter load wheel, the housing assembly also having a mounting structure for fixedly securing the housing assembly to a base element. At 704 the housing assembly is coupled to the cylindrical support element such that the cylindrical support element is disposed between the pair of load bearing wheels and the at least a counter load wheel. At 706 the coupled-together housing assembly and solar collector assembly is fixedly secured to a base element via the mounting structure of the housing assembly and a complementary mounting structure of the base element, such that the pair of load bearing wheels rollingly engage the outer surface of the cylindrical support element and bear the weight of the cylindrical support element. [0042] Numerous other embodiments may be envisaged without departing from the scope of the instant invention.

Claims

CLAIMS What is claimed is:

Claim 1. A solar collector system, comprising:

a movable solar collector surface;

a support element coupled to the solar collector surface, the support element having a length and having an outer surface that defines a circle in a cross section taken in a plane normal to the length, the support element being rotatable about a longitudinal axis defined along the length thereof;

a housing assembly having a mounting end and a bearing end, the mounting end comprising a mounting structure for fixedly securing the housing assembly to a base element, the bearing end defining an opening for receiving the support element when the housing assembly and the support element are coupled together such that the housing assembly at least partially encircles a portion of the outer surface of the support element, the encircled portion of the outer surface defining a bearing surface of the support element;

a pair of first wheels mounted to the bearing end of the housing assembly, each first wheel of the pair of first wheels disposed adjacent to the opening and protruding into the opening for contacting a portion of the bearing surface that faces toward the mounting end of the housing assembly when the housing assembly and the support element are coupled together; and,

at least one second wheel mounted to the bearing end of the housing assembly, the at least one second wheel disposed adjacent to the opening and protruding into the opening for contacting a portion of the bearing surface that faces away from the mounting end of the housing assembly when the housing assembly and the support element are coupled together, wherein the housing assembly and the support element are coupleable together prior to securing the housing assembly to the base element.

Claim 2. A solar collector system according to claim 1 , wherein the at least one second wheel comprises a pair of second wheels.

Claim 3. A solar collector system according to claim 1, wherein the support element has a first diameter that is substantially uniform along the length of the support element.

Claim 4. A solar collector system according to claim 3, wherein each wheel of the pair of first wheels has a second diameter, the second diameter smaller than the first diameter.

Claim 5. A solar collector system according to claim 4, wherein the second diameter is less than 50% of the first diameter.

Claim 6. A solar collector system according to claim 3, wherein the first diameter is at least six inches.

Claim 7. A solar collector system according to claim 1, wherein the pair of first wheels and the at least one second wheel are mounted to the housing assembly absent a drive mechanism for driving rotation of the support element via either the pair of first wheels or the at least one second wheel.

Claim 8. A solar collector system according to claim 1, wherein each one of the pair of first wheels and the at least one second wheel are fabricated using nylon.

Claim 9. A solar collector system according to claim 1, wherein the support element is axially movable relative to the pair of first wheels and relative to the at least one second wheel.

Claim 10. A solar collector system according to claim 1, wherein the housing assembly includes first and second housing elements and a retaining element for detachably coupling together the first and second housing elements.

Claim 11. A solar collector system according to claim 1 , wherein the first group of the wheels rollingly engages the outer surface of the support element and bears the weight of the support element and the second group of the wheels acts as counter load wheels.

Claim 12. A solar collector system according to claim 11, wherein an angle that is formed between the pair of load bearing wheels and having a vertex at a point along the longitudinal axis of the support element is between 50° and 130°.

Claim 13. A method, comprising:

providing a solar collector assembly comprising a solar collector surface that is coupled to a cylindrical support element, the cylindrical support element having an outer surface and a length;

providing a housing assembly having a plurality of wheels mounted thereto including a pair of load bearing wheels and at least a counter load wheel, the housing assembly having a mounting structure for fixedly securing the housing assembly to a base element;

coupling the housing assembly to the cylindrical support element such that the cylindrical support element is disposed between the pair of load bearing wheels and the at least a counter load wheel; and,

fixedly securing the coupled-together housing assembly and solar collector assembly to a base element via the mounting structure of the housing assembly and a complementary mounting structure of the base element, such that the pair of load bearing wheels rollingly engage the outer surface of the cylindrical support element and bear the weight of the cylindrical support element.

Claim 14. A method according to claim 13, wherein coupling the housing assembly to the cylindrical support element comprises arranging the cylindrical support element between a first housing element and a second housing element, and securing the first housing element to the second housing element on opposite sides of the cylindrical support element.

Claim 15. A method according to claim 13, wherein the at least one counter load wheel comprises a pair of counter load wheels, and comprising coupling the housing assembly to the cylindrical support element such that the cylindrical support element is disposed between a substantially symmetric arrangement of the pair of load bearing wheels and the pair of counter load wheels.