WO2014036600A1

WO2014036600A1 - Guide roller assembly for floating solar collectors

Info

Publication number: WO2014036600A1
Application number: PCT/AU2013/001001
Authority: WO
Inventors: Allan James Yeomans
Original assignee: Allan James Yeomans
Priority date: 2012-09-07
Filing date: 2013-09-06
Publication date: 2014-03-13
Also published as: AU2012101379A4

Abstract

Radiant solar energy collecting apparatus (10) which includes a platform (13) which floats on liquid in a liquid reservoir (11) and which carriers radiant energy collecting apparatus (17), the platform (13) being capable of being at least partially sunk in the reservoir for covering or during covering of the concentrators (18) or collectors (28) with liquid, and a plurality of guide roller assemblies (22) between the platform (13) and reservoir (11), the guide roller assemblies (22) being capable of swiveling about horizontal axes so that the guide roller assemblies (22) can guide movement of the platform (13) when rotated about a substantially vertical axis and movement of the platform (13) when being moved longitudinally of the axis towards or away from the at least partially sunk position in the reservoir (11).

Description

GUIDE ROLLER ASSEMBLY FOR FLOATING SOLAR COLLECTORS

Technical Field

[0001] The present invention relates to radiant solar energy collecting apparatus and in particular to a guide roller assembly for guiding the movement of radiant solar energy collecting apparatus.

Background of the Invention

[0002] In my International Patent Application No. PCT/AU92/00153, I describe solar energy collecting apparatus which includes a liquid reservoir containing liquid such as water, a platform floating on the liquid in the reservoir, a drive for pivoting or rotating the platform about a vertical axis, and radiant energy collectors supported on the platform, the collectors including concentrators typically mirrors for directing radiant solar energy towards radiant energy absorbers or other solar energy collecting target. In that apparatus, at least the concentrators are capable of being selectively submerged beneath the surface of the liquid for protection against inclement weather conditions, such as in high winds, hail or heavy rain. This is achieved by covering the concentrators on the platform with liquid for example by pumping liquid such as water onto the platform or by establishing a low pressure beneath the platform to submerge or partially submerge the platform and concentrators and restrain the platform against the buoyant forces on the platform.

[0003] Usually the liquid reservoir comprises a circular water container or reservoir which may for example comprise a pond or a dam or a purpose built container and the platform is constructed of a buoyant material, mounted on a layer of such material or may be formed with sealed air reservoirs or provided with other means to make it buoyant. In yet another alternative, the platform may be provided with one or more chambers or reservoirs which may contain or be filled with air to enable the platform to. float or be filled with water to sink and/or submerge the platform to cover the concentrators with liquid in the reservoir. [0004] Guide rollers may be mounted around the inside the container or reservoir wall to engage with a hoop around the periphery of the platform so as to maintain the relative position of the platform within the reservoir and guide the rotational or pivoting movement of the platform as it tracks movement of the sun.

[0005] In an alternative arrangement as disclosed in my International patent application No. PCT/AU 99/00140 (AU742755), the platform may carry solar energy collectors in the form of photovoltaic cells for direct generation of electrical power. Again in such an arrangement, it is desirable to cover the photovoltaic cells with a layer of liquid for example by submerging or partly submerging the platform in the reservoir if there is a rapid onset of hail or other inclement weather conditions.

[0006] Whilst the guide rollers are effective in guiding movement of the platform as above, a disadvantage encountered with the use of the current guide rollers is that they tend to interfere with movement of the platform when it is desired to submerge the platform in the body of liquid or water to protect the solar concentrators or collectors should a risk of hail or other damaging weather phenomena look imminent.

[0007] It would be desirable if a means were available which addressed one or more of the above disadvantages or which at least provided an alternative to the currently known arrangements.

Summary of the Invention

[0008] In one preferred aspect, the present invention provides a radiant solar energy collecting apparatus including a liquid reservoir, a platform adapted to float on liquid in said liquid reservoir, solar energy collectors or concentrators supported on the platform and a plurality of guide roller assemblies between said platform and reservoir, said guide roller assemblies being adapted to guide movement of said platform when rotated about a substantially vertical axis, said guide roller assemblies being further adapted to guide movement of said platform when said platform moves longitudinally of said axis.

[0009] The platform moves longitudinally of the axis of rotation when the platform is at least partially sunk or submerged within liquid in the reservoir during covering at least the concentrators or collectors with liquid for protection thereof against inclement weather conditions. The concentrators or collectors may be covered with liquid pumped onto or otherwise directed onto the platform which will due to the weight of the liquid cause the platform to at least partially sink or lower within the liquid in the reservoir. Alternatively, the platform may be sunk or submerged within the liquid in the reservoir by other means so that that liquid of the reservoir covers and protects the concentrators or collectors. The platform also moves longitudinally of the axis of rotation when the platform is moved from its sunk or submerged or partially sunk or submerged position back to its operative position in which it can be rotated about the axis of rotation to enable it to track movement of the sun.

[0010] Preferably each roller assembly includes a roller rotatable about a roller axis with the roller assembly being mounted for free movement about a swivel axis extending substantially horizontal and at right angles or normal to the axis of rotation of the roller. Preferably the swivel axis is offset from the roller axis so that the roller assembly is capable of free rotation about the swivel axis to follow the direction of movement of the platform.

[0011] Preferably the roller assemblies are mounted at spaced circumferential locations around the platform and reservoir.

[0012] Most preferably the rollers assemblies are mounted at spaced circumferential locations to the platform such that at least some of the rollers are adapted to be in rolling contact with an inner wall of the reservoir.

[0013] Alternatively, the roller assemblies are mounted at spaced circumferential locations to a side wall of the reservoir such that at least some of the rollers are in rolling contact with the platform. In this embodiment, the platform may carry an external annular hoop or rim and at least some of the rollers are in rolling contact with the hoop or rim.

[0014] The or a further hoop or rim may extend above the platform to define an annular barrier or wall to constrain liquid or water on the platform covering the concentrators or collectors. [0015] Most preferably the roller assemblies comprise caster wheel or roller assemblies having rotatable rollers which are free to pivot about swivel axes at right angles to the roller axes.

[0016] The present invention in a further aspect provides a platform assembly adapted to float on liquid in a liquid reservoir to support radiant energy collecting apparatus, and a plurality of guide roller assemblies between said platform and reservoir, said guide roller assemblies being adapted to guide movement of said platform assembly when rotated about a substantially vertical axis when said radiant energy collecting apparatus tracks movement of the sun, said guide roller assemblies being further adapted to swivel to guide movement of said platform when being moved towards a position at least partially sunk or submerged in liquid in said reservoir for protection of said radiant energy collecting apparatus, or being raised from said position.

[0017] The radiant energy collecting apparatus suitably includes solar energy collectors or concentrators supported on the platform assembly, the concentrators or collectors being covered with or submerged within liquid when the platform assembly is at least partially sunk in liquid in the reservoir for protection of the concentrators or collectors against inclement weather conditions.

[0018] An external annular hoop or rim may be provided around the platform assembly for constraining liquid on the platform assembly. The guide roller assemblies may be mounted to the reservoir whereby at least some of the rollers thereof are in rolling contact with the hoop or rim. Alternatively, the guide roller assemblies are mounted to the platform assembly whereby at least some of the rollers thereof are in rolling contact with a peripheral wall of the reservoir.

[0019] The term "liquid reservoir" as used throughout the specification includes any liquid or water container or reservoir which may for example comprise a pond or a dam or a purpose built liquid container. Further the term "concentrators" include solar energy reflectors or mirrors whilst the term "collectors" include photovoltaic cells or other radiant solar energy collector means. Brief Description Of The Drawings

[0020] Reference will now be made to the accompanying drawings which illustrate a preferred embodiment of the invention and wherein:

[0021] Fig. 1 is a schematic plan view of solar energy collecting apparatus incorporating guide wheel or roller assemblies according to an embodiment of the present invention;

[0022] Fig. 2 is an enlarged sectional view along the line A-A of Fig. 1 ;

[0023] Figs. 3 is an enlarged sectional view from the side of an edge portion of the platform and showing a guide wheel or roller assembly of the apparatus in its normal mode of operation;

[0024] Fig. 3A is a view in the direction B of Fig. 1 ; and

[0025] Fig. 4 is an enlarged view corresponding to Fig. 3 showing a guide wheel or roller assembly of the apparatus in its second mode of operation when the platform is being submerged.

Description of the Preferred Embodiment

[0026] Referring to the drawings and firstly to Figs. 1 to 2, there is illustrated solar energy collecting apparatus 10 according to one preferred form of the present invention, including a circular water container or reservoir 11 , which may for example comprise a pond or a dam or a purpose built container, the reservoir 11 having an outer circumferential wall 12 which encloses and contains water within the container 11. A platform or platform assembly 13 is located within the container 11 so as to float on water 14 contained therein which is at the level 15. The platform 13 may be constructed of a buoyant material such as a foam plastics material or be mounted on a layer of such material. Alternatively, the platform 13 may be formed with sealed or open air reservoirs 16 on its underside or provided with other means to make it buoyant. [0027] Supported on the platform 13 are a plurality of solar collector assemblies 17 arranged as shown in Fig. 1 in a side-by-side attitude and each comprising as shown more clearly in Fig. 2, a solar energy concentrator 18 comprising a series of parallel mirrors or reflectors 18' either of curved form or planar form and angled so as to act as and define one large elongated parabolic concentrator. The concentrators 18 are arranged to focus the sunlight on a secondary concentrating assembly 19 which is mounted on a suitable frame 20 above the concentrators 18. Extending around the outer periphery of the platform 13 is an upstanding hoop or rim defining an annular barrier or wall 13' which serves to constrain water on the platform assembly 13 for flooding the platform 13 and submerging at least the concentrators 18.

[0028] Any suitably drive system may be provided for rotating or pivoting the platform 13 about a substantially vertical central axis 21 to enable the collector assemblies 17 to track movement of the sun as described for example in my above international patent application. Rotation of the floating platform 13 rotates the collector assemblies 17 so that the longitudinal axes of the concentrators 18 lie in vertical planes which intersect the sun. As the sun moves across its arc, its change in longitudinal meridian at the horizon will be tracked by the concentrators 18 with the platform 13 floating on the liquid 14 in the container 11 and carrying the concentrators 18 being rotated by its drive system so that the longitudinal axes of the concentrators 18 remain aligned with the sun. Thus at all times when the sun is up, the collector assemblies 17 are exposed to maximum radiant energy from the sun to thereby maximize energy collection. The use of the floating platform 13 allows for easy and convenient movement of the apparatus to achieve and maintain alignment of the concentrators 8 with the sun.

[0029] Should a risk of hail or other damaging weather phenomena look imminent, water is pumped at high volume onto the top of the platform 13 on which it is constrained by the barrier 13'. Thus water will cover the platform 13 and associated solar concentrators 18 to prevent damage thereto. This will also cause the platform 13 to at least partially sink. Alternatively, other means may be provided to submerge the platform 13 and concentrators 18 within the water 14 in the reservoir 12 for example by filling chambers beneath the platform 13 with water or by applying a suction pressure to the underside of the platform 13. [0030] For guiding the sun tracking movement of the platform 13 and collector assemblies 17 within the reservoir 12, a plurality of roller assemblies 22 are arranged at circumferentially spaced positions between the platform 13 and reservoir 1 , each roller assembly 22 including a freely rotatable roller or wheel 23 rotatable about an axis 23' as shown in Figs. 3 and 3A. In this embodiment, each roller assembly 22 is mounted to the platform 13 such that the rollers 23 thereof can be in rolling contact with the inner surface of the wall of 12 of the reservoir 11. The rollers 23 thus act as bearings to maintain the platform 13 centrally in the reservoir 11 as it rotates about the vertical axis 21.

[0031] Each roller 23 is supported on a frame or mount 24 which is mounted to the platform 13 for free rotation about a substantially horizontal swivel axis 25. The swivel axis 25 is offset circumferentially from the axis of the roller 23 as is apparent in Fig. 3A such that the swivel axis 25 leads the roller axis 23' relative to the normal direction of movement C of the platform 13. The roller assemblies 22 are thus in the nature of caster wheels or rollers.

[0032] In the normal mode of operation, that is when the platform 13 is being rotated to track movement of the sun, for example when it is moved in the direction C in Fig. 3A, the rollers assemblies 22 are in the attitude of Fig. 3A with the rollers 23 being in rolling contact with the inner surface of the wall 12 of the reservoir 11 and having their axes of rotation 23' substantially vertical and trailing the respective swivel axes 25.

[0033] When however the platform 13 moves downwardly in the direction D and at least partially sinks within the water in the reservoir 11 for example by being flooded with water to cover the concentrators 18 and protect the concentrators 18 from damage from hail or other inclement weather conditions, the roller assemblies 22 will rotate about the horizontal swivel axes 25 towards the position of Fig. 4 due to their contact with the surface of the wall 12 and as allowed by the freely rotatable frame 24 of the roller assemblies 22 and the offset pivotal mounting. The rollers 23 thus now have their rotational axes 23' in a substantially horizontal attitude so that they guide the submerging or lowering movement of the platform 13. Similarly when the platform 13 is caused to rise or float back towards its operative position of Fig. 3 in a direction opposite the direction D, the rollers 23 will adopt a position opposite to that shown in Fig. 4 due to the offset swivel mounting defined by the axis 25. When the platform 13 is back in its operative floating position of Figs. 3 and 3A and commences to rotate about the central rotational axis 21 , the relative movement between the platform 13 and reservoir wall 12 will cause pivoting of the roller assemblies 22 and thus rollers 23 about the swivel axis 25 so that the rollers 23 will adopt the position of Figs. 3 and 3A and guide the rotational movement of the platform 13 about the axis 21.

[0034] Whilst in the above described embodiment, the roller assemblies 22 are described as being mounted to the platform 13, the rollers assemblies 22 alternatively may be mounted to the wall 12 of the reservoir 11. In this embodiment, the platform 13 may be provided with a further rim or hoop 26 which is attached to or formed integrally with the platform 13 or which may be an downward extension of the barrier or wall 13' so as to define a circular or annular skirt around the outer diameter of the platform 13. The rim or hoop 26 may extend below the underside of the platform 13 as shown in Fig. 2.

[0035] The guide roller assemblies 22' as shown in dotted outline in Fig. 2 are mounted at spaced circumferential positions around the inside diameter of the reservoir wall 12 so that the rollers 23 press against the hoop or rim 26 so as to maintain the relative position of the platform 13 within the reservoir 11 as the platform 13 is rotated within the reservoir 11. Further the rollers assemblies 22' will rotate about substantially horizontal swivel axes during downward or upward movement of the platform 13 through engagement wijh the rim or hoop 26 in a similar manner to that described above with reference to Figs. 3, 3A and 4.

[0036] It will be appreciated that the roller assemblies 22 may be in many different configurations provided that the rollers 23 are mounted so as to be capable of movement to follow the direction of movement of the platform 13. Thus the roller assemblies are preferably mounted for free rotation about swivel axes at right angles to their axes of rotation. Further it will be appreciated that the roller assemblies can rotate freely in any direction about their swivel axes. [0037] The water or liquid upon which the platform is supported for floating movement is preferably arranged within a reservoir, however, the water or liquid may comprise any other body of liquid such as water in a river, sea or other storage container.

[0038] In the embodiment described above, the platform 13 supports solar energy concentrators 18 in the form or mirrors or reflectors. In an alternative embodiment, the platform 13 may carry photovoltaic cells or other solar energy collectors. For example as shown in dotted outline in Fig. 3, the platform 13 may be provided with a series of surfaces 27 angled to the mean declination of the sun with each surface 27 carrying photovoltaic cells 28. In this arrangement, when the platform 13 is flooded, the photovoltaic cells 28 will be covered with water or liquid and thereby be protected in inclement weather conditions.

[0039] The reference to prior art herein including reference to prior patents and patent applications is not to be taken as an admission that such prior art constitutes common general knowledge in the art.

[0040] The terms "comprising" or "comprises" as used throughout the specification are taken to specify the presence of the stated features, integers and components referred to but not preclude the presence or addition of one or more other feature/s, integer/s, component/s or group thereof.

[0041] Whilst the above has been given by way of illustrative embodiment of the invention, all such modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as herein set forth in the appended claims.

Claims

1. Radiant solar energy collecting apparatus including a liquid reservoir, a platform adapted to float on liquid in said liquid reservoir, solar energy collectors or concentrators supported on the platform and a plurality of guide roller assemblies between said platform and reservoir, said guide roller assemblies being adapted to guide movement of said platform when rotated about a substantially vertical axis, said guide roller assemblies being further adapted to guide movement of said platform when said platform moves longitudinally of said axis.

2. Radiant solar energy collecting apparatus as claimed in claim 1 wherein each roller assembly includes a rotatable roller rotatable about a roller axis, and wherein said roller assembly is mounted for free movement about a swivel axis extending substantially horizontal and normal to said roller axis.

3. Radiant solar energy collecting apparatus as claimed in claim 2 wherein said swivel axis is offset from said roller axis whereby the roller assembly is capable of free rotation about the swivel axis to follow the direction of movement of the platform.

4. Radiant solar energy collecting apparatus as claimed in any one of claims 1 to 3 wherein said roller assemblies are mounted at spaced circumferential locations around the platform and reservoir.

5. Radiant solar energy collecting apparatus as claimed in claim 4 wherein said roller assemblies are mounted at spaced circumferential locations to the platform whereby at least some of said rollers are in rolling contact with an inner wall of said container.

6. Radiant solar energy collecting apparatus as claimed in claim 4 wherein said roller assemblies are mounted at spaced circumferential locations to the container whereby at least some of said rollers are in rolling contact said platform.

7. Radiant solar energy collecting apparatus as claimed in claim 4 wherein said platform carries an external annular hoop or rim and wherein at least some of said rollers of said roller assemblies are in rolling contact with said hoop or rim.

8. Radiant solar energy collecting apparatus as claimed in claim 7 wherein said platform carriers an annular barrier or wall which extends above said platform to constrain liquid or water on said platform for covering said concentrators or collectors.

9. A platform assembly adapted to float on liquid in a liquid reservoir to support radiant energy collecting apparatus, and a plurality of guide rollers assemblies between said platform and reservoir, said guide roller assemblies being adapted to guide movement of said platform assembly when rotated about a substantially vertical axis when said radiant energy collecting apparatus tracks movement of the sun, said guide roller assemblies being further adapted to swivel to guide said platform when being moved towards a position at least partially sunk in liquid in said reservoir for protection of said radiant energy collecting apparatus or being raised from said position.

10. A platform assembly as claimed in claim 9 wherein said radiant energy collecting apparatus includes solar energy collectors or concentrators supported on said platform assembly and wherein said concentrators or collectors are covered with or submerged within liquid when said platform assembly is at least partially sunk in liquid in said reservoir.

11. A platform assembly as claimed in claim 10 and including a external annular hoop or rim around said platform assembly for constraining liquid on said platform assembly.

12. A platform assembly as claimed in claim 11 wherein said guide roller assemblies are mounted to said reservoir whereby at least some of said rollers thereof are in rolling contact with said hoop or rim.

13. A platform assembly as claimed in claim 9 wherein guide roller assemblies are mounted to the platform assembly whereby at least some of the rollers thereof are in rolling contact with a peripheral wall of the reservoir.