NL2006117C2

NL2006117C2 - Solar energy system.

Info

Publication number: NL2006117C2
Application number: NL2006117A
Authority: NL
Inventors: Jan Kranendonk
Original assignee: Kranendonk Inv S Holding B V Van
Priority date: 2010-11-10
Filing date: 2011-02-02
Publication date: 2012-05-14
Also published as: WO2012064189A3; WO2012064189A2

Description

SOLAR ENERGY SYSTEM

The present invention relates to a solar energy system, and more specifically a solar energy system 5 comprising a plurality of solar units.

The invention is further related to a method for adjusting the plurality of solar units within the proposed solar energy system.

To be able to reduce the cost of solar energy 10 systems, it is of vital importance to keep the weight low while still maintaining structural integrity. Also, a solar system that can follow the sun's movement should be able to aim itself toward the sun. For solar energy systems that are capable of orientating the solar cells towards the sun, it 15 is common practice to have independent electric motors for every solar unit or every panel of photovoltaic elements. Such systems are heavy, and the large amount of electric motors requires maintenance and possibly replacement of motors that have failed. Besides this, the large amount of 20 electric motors required makes the system more expensive.

An object of the present invention is to provide a solar energy system with a plurality of solar units, that is improved relative to the prior art and wherein at least one of the above stated problems is obviated.

25 Said object is achieved with the solar energy system according to the present invention, comprising: - a plurality of solar units ; - suspension means for suspending the plurality of solar units, said suspension means comprising an upper net 30 and a lower net oriented parallel in a plane, a distance existing therebetween; - wherein at least two drive means are arranged to the suspension means such that the upper and lower net are 2 moveable relative to each other in the plane by the drive means; and - wherein every solar unit is arranged to both the upper and the lower net such that the orientation of the 5 solar units is adjustable via the drive means driving the suspension means.

The solar system proposed uses a structure that is build out of nets. By using the principle of tension, a very strong, lightweight structure is possible, that is easily 10 produced on a large scale. Also, by moving the nets relative to each other, solar units that are connected to the nets can be aimed at the sun all at once. This structure is completely modular and requires only two drives.

Moreover, the net structure provides a solar 15 energy system that can be easily transported to remote

locations, since it requires only limited space in collapsed state, and furthermore comprises mainly lightweight components. For example, (metal) wires of a relatively thin cross sectional area are able to withstand the high tensile 20 forces required for pre-tensioning the net structure. A

profile beam structure - as applied in conventional solar energy system for supporting solar panels - that spans the same distance would be significantly heavier.

According to a preferred embodiment, the solar 25 energy system comprises only two drive means, as this suffices for all movements required for the solar units to follow the path of the sun during the day and for each successive day over the year.

According to a preferred embodiment, 30 - the upper and lower net are substantially identical and each net comprises a plurality of rows, each row comprising an array of rhombuses; 3 - each rhombus comprises two rhombus-corners substantially oriented in the longitudinal direction of the row, and two rhombus-corners substantially transverse to the longitudinal direction of the row; and 5 - the solar units are arranged to the rhombus- corners that are substantially transverse to the longitudinal direction of the row.

The solar units being arranged to the rhombus-corners of the rhombuses that are substantially transverse 10 to the direction of the row, while the other corners of the rhombuses are substantially oriented in the direction of the row, allow the solar units to be moved independently in the X- and Y-direction, and every combination thereof. The corners of the rhombuses that are substantially oriented in 15 the direction of the row is a node of the net that functions as a pivot point for orientating the solar units suspended by the net structure.

According to a further preferred embodiment, the upper and lower net are quadrangular, and the at least two 20 drive means are arranged to adjacent corner pairs of the upper and lower net. The quadrangular form, that is more preferably a rectangle or rhombus, significantly simplifies the solar energy system because it allows the X- and Y-direction to be driven independently.

25 According to a further preferred embodiment, rhombus-corners that are substantially oriented in the longitudinal direction of the rows of rhombuses are connected by wires, thereby forming a web structure in the plane of the net. These wires connect the corners of the 30 rhombuses that are substantially oriented in the direction of the row, i.e. the nodes of the net that function as a pivot point for orientating the solar units suspended by the net structure.

4

This connection on the one hand improves the coupling between all solar units suspended between the upper and lower net, providing an improved simultaneous adjustability of the plurality of solar units. On the other 5 hand, the wires distribute the pre-tensioning forces applied to the net structure, allowing for an increased pretensioning, which reduces sagging of the net structure under it's own weight. Less sagging is beneficial, since it reduces orientation differences between solar units 10 positioned in the center of the net structure, and solar units positioned near the edges thereof.

According to a further preferred embodiment, the drive means comprise or are driveably connected to a rigid spacing element to which both the upper and lower net are 15 arranged, and the corner of the net opposite the corner of the net where the driveable rigid spacing element is arranged comprises a further rigid spacing element that is pivotably arranged at a pivot point substantially halfway between the upper and lower net attachment points.

20 With this configuration, only one drive is required. The rigid spacing element in the opposite corner pivots around it's pivot point, when the driven corner is driven by the drive means. The pivot point of both rigid spacing elements being located substantially halfway between 25 the upper and lower net attachment points allows the upper and lower net to remain parallel.

According to a further preferred embodiment, - the drivable rigid spacing element and the pivotably arranged rigid spacing element in the opposite 30 corner are oriented substantially parallel, such that the rigid spacing elements arranged between the corners of the upper and lower net, together with the upper and lower net define a parallelogram-shape.

5

It is advantageous if the nets move parallel and the distance between the points where the solar units are arranged to the upper and lower net remain unchanged. This allows a uniform adjustability of all solar units suspended 5 between the upper and lower net.

According to a further preferred embodiment, the solar energy system further comprises tensioning members arranged between support members forming the foundation of the solar energy system, and the pivot points of the rigid 10 spacing elements, said pivot points being located substantially halfway between the upper and lower net attachment points.

By the tensioning members pre-tensioning the rigid spacing elements in their respective pivot points 15 substantially halfway between the upper and lower net, the forces required for suspending the net structure with the solar units arranged therein is decoupled from the forces required for driving the upper and lower net relative to each other.

20 According to a further preferred embodiment, the edges of the upper and/or lower net are provided with a main suspender cable that is suspended in a substantially parabolic shape between the net corners. This main suspender cable provides a substantially homogeneous force 25 distribution over the net, similar to the principle of a suspension bridge.

The invention is further directed to a method for adjusting the plurality of solar units within a solar energy system as described above, the method comprising the step of 30 driving the drive means arranged to the suspension means, thereby moving the upper and lower net of the suspension means relative to each other in their plane, and thereby 6 adjusting the orientation of the solar units arranged between the upper and the lower net.

According to a further preferred embodiment, the solar energy system further comprises control means 5 configured for adjusting the plurality of solar units according to the method described above.

In the following description preferred embodiments of the present invention are further elucidated with reference to the drawing, in which: 10 Figure 1 is a perspective view of a solar energy system according to the present invention;

Figure 2 is a top view of the nets of the solar energy system shown in figure 1;

Figure 3 is a detailed perspective view of a 15 corner area of the solar energy system shown in figure 1;

Figure 4A is a side view of the drive means in a first state; and

Figure 4B is a side view of the drive means of figure 4A in a second state; 20 Figure 5 is a simplified 3-dimensional view without perspective of the nets and drive means of the solar energy system shown in figure 1;

Figure 6 is a side view of the solar energy system shown in figure 1, wherein the solar units are adjusted into 25 a first orientation by moving the nets relative to each other in Y-direction, the solar units being substantially oriented upwards;

Figure 7 is a top view of the nets of the solar energy system shown in figure 1, with the nets and solar 30 units according to the first orientation shown in figure 6;

Figure 8 is a front view of the solar units when the solar units are oriented in the first orientation shown in figures 6 and 7; 7

Figure 9 is a side view of the solar energy system shown in figure 1, wherein the solar units are adjusted into a second orientation by moving the nets relative to each other in Y-direction, the solar units being substantially 5 oriented straight ahead;

Figure 10 is a top view of the nets of the solar energy system shown in figure 1, with the nets and solar units according to the second orientation shown in figure 9;

Figure 11 is a front view of the solar units when 10 they are oriented as shown in figures 9 and 10;

Figure 12 is a side view of the solar energy system shown in figure 1, wherein the solar units are adjusted by moving the nets relative to each other in X-direction; 15 Figure 13 is a top view of the nets of the solar energy system shown in figure 1, with the nets and solar units according to the orientation shown in figure 12;

Figure 14 is a front view of the solar units when they are oriented according to figures 12 and 13; 20 Figure 15 is a detailed top view of a solar unit wherein the upper and lower net are moved a distance ΔΧ relative to each other.

Figure 16 is a detailed top view of the solar unit shown in Figure 15, wherein the upper and lower net are 25 moved a distance ΔΧ and ΔΥ relative to each other.

Figure 17 is a perspective view of a single solar unit according to the orientation shown in figures 12-14;

Figure 18 is a perspective view of a solar unit of the solar energy system wherein sunlight is reflected into a 30 focal point; and

Figure 19 is a cross sectional view of the solar unit shown in figure 18.

8

The solar energy system 1 shown in figure 1 comprises a plurality of solar units 2 suspended by suspension means 4, said suspension means comprising an upper net 6 and a lower net 8. The solar units 2 are 5 attached to both the upper net 6 and lower net 8.

The upper and lower net 6, 8 are arranged with their respective corners 20, 22 to rigid spacing elements 26, 28. In the embodiment shown in figure 1, the rigid spacing elements 26 are driveable via drive means 10, 10 whereas the opposite rigid spacing elements 28 is pivotably arranged to the tensioning member 30.

The solar units 2 are arranged to both the upper net 6 and lower net 8, and will undergo an angular movement when the upper and lower net 6, 8 are moved relative to each 15 other in their the plane, i.e. their in-plane direction.

The structure of the inner wires of the nets 6, 8 is such that any solar unit 2 arranged between the nets is able to move freely without getting into contact with itself, other solar units 2, or the nets 6, 8.

20 By moving the nets with respect to each other, it is possible to "aim" the solar units 2 hanging in the nets 6, 8. This way, all solar units 2 can be pointed continuously towards the moving sun. The nets 6, 8 can be sized to any scale or amount of solar units 2 arranged.

25 The side-wires forming the edges of the nets 6, 8 are a suspension cable 38 suspended in a substantially parabolic shape, to obtain a homogeneous force distribution across the centre-part of the nets 6, 8, similar like the principle of a suspension bridge (figure 2). This enables to 30 hang the nets 6, 8 with the least amount of deflection.

The centre-part of the nets is repetitive in structure. The wires that connect to a solar unit 2 converge and diverge again towards the next solar unit 2, thereby 9 forming a row 12 comprising an array of rhombuses 14. Every solar unit 2 is arranged to both upper and lower net 6, 8 in a diamond-shaped / rhomboidal fashion.

Each diamond / rhombus comprises two rhombus-5 corners 16 substantially oriented in the direction of the row 12, and two rhombus-corners 18 substantially transverse to the direction of the row 12. The rhombus-corners 18 form the attachment points for the solar units 2.

The rhombus-corners 16 are connected by wires 24, 10 thereby forming a web structure in the plane of the net 6, 8. Said web structure couples different rows 12. It furthermore allows a greater pre-tensioning to be applied to the net structure, thereby reducing sagging of the net structure .

15 In figure 2 each of the four corners of a solar unit 2 is arranged to either the upper net 6, or the lower net 8. The rhombus-corners 16 are connected by wires 24, thereby forming a web structure in the plane of the net 6, 8. The rhombus-corners 16 allow the solar units 2 to be 20 orientated by moving the upper and lower net 6, 8 independently in X- or Y-direction. This relative movement of the upper and lower net 6, 8 allows the plurality of solar units 2 to be simultaneously adjusted into a desired orientation .

25 Figures 4A and 4B show the drive means 10 that are located at the corners 20, 22 of the upper and lower net 6, 8, and it consists of an arched threaded rod 54 extending between the corner 20 of the upper net 6 and the corner 22 of the lower net 8. A straight bar provides a rigid spacing 30 element 26 between the corners 20, 22, and is constructed in such way that the connections points of the corners 20, 22 can rotate in the plane of the drive means 10. Figure 4B shows a state wherein the drive means are rotated relative 10 to the state shown in figure 4A. When two of the four corners 20, 22 of the nets 6, 8 are connected to a drive 10, it is possible to steer the nets 6, 8 in every possible direction with respect to each other.

5 Halfway the rigid spacing element 26 there is provided a triangular member 56 that extends around the threaded rod 54. A tensioning members 30 is arranged between the triangular member 56 and a support member 36 that forms the foundation of the solar energy system. The tensioning 10 members 30 pre-tension the suspended net structure in order to reduce sagging thereof to a minimum.

An electric motor 50 is driveably connected to the threaded rod 54 through a gear 52 that is also threaded on the inside. When the motor 50 rotates, the threaded rod 54 15 is pushed into a circular motion around the center pivot 32 of the bar-like rigid spacing element 26.

The arrangement connecting the pivot point 32 of the rigid spacing element 26 via the triangular member 56 via the tensioning member 30 to the support member 36 20 decouples the drive mechanism from the pre-tensioning forces. The triangular member 56 moves round the threaded arched rod 54, and the drive means 10 actuate the rigid spacing element 26 around the pivot point 26 when moving the upper and lower net 6, 8 relative to each other. The forces 25 used to pull the nets 6, 8 into tension are not carried by the electric motor 50, but instead are carried by the connection to the foundations 36 of the system.

Figure 5 is a simplified 3-dimensional view without perspective of the nets 6, 8 and drive means 10 of 30 the solar energy system 1 of figure 1. The embodiment shown in both figures 1 and 5 comprises two drive means 10 that are arranged to adjacent corner pairs 20, 22 of the upper and lower net 6, 8.

11

The drivable rigid spacing element 12 and the pivotably arranged rigid spacing element 28 in the opposite corner are preferably oriented parallel, such that the rigid spacing elements 12, 14 arranged between the corners 20, 22 5 of the upper and lower net 6, 8, together with the upper and lower net 6, 8 define a parallelogram-shape. A parallelogram-shape has the significant benefit that the upper and lower net 6, 8 remain parallel, which allows a uniform adjustability of all solar units 2 suspended by the 10 net structure.

Although not required, a quadrangular form, that is more preferably a rectangle or rhombus, and even more preferably a square as shown in the embodiment of figure 1, has the advantage that it significantly simplifies the solar 15 energy system because it allows the X- and Y-direction to be driven independently. This will be shown in detail using figures 6-16 .

Figure 6 shows a side view the solar energy system 1, wherein the solar units 2 are adjusted into a first 20 orientation by moving the upper and lower nets 6, 8 relative to each other in the Y-direction. In this first orientation, the solar units 2 are substantially oriented upwards, thereby pointed towards a sun position relatively high above the horizon. The situation of figure 6 is shown in top view 25 in figure 7, and figure 8 is a front view of the solar units 2 when they are oriented in the first orientation shown in figures 6 and 7.

Figure 9 shows a side view the solar energy system 1, wherein the solar units 2 are adjusted into a second 30 orientation wherein the solar units 2 are substantially oriented straight, thereby pointed towards a sun position relatively close to the horizon.

12

Adjusting the solar units from the first orientation shown in figures 6-8 into the second orientation subject of figures 9-11 is the result of moving the upper and lower nets 6, 8 relative to each other in the Y-5 direction only.

When the upper and lower nets 6, 8 are moved relative to each other in solely the X-direction, the solar units 2 are moved into a further orientation that is subject of figures 12-14. Figure 15 also shows a top view wherein 10 the nets are moved a distance ΔΧ relative to each other.

Combining the movements in both X- and Y-direction, it is possible to steer the solar units 2 in every desired orientation required for following the path of the sun during the day (from East to West) and for each 15 successive day over the year (with different elevations over the seasons). Figure 16 shows a combined relative displacement over distances ΔΧ and ΔΥ.

Figure 17 shows a solar unit 2 in the same orientation as shown in figures 12-14. The solar unit 2 is 20 arranged to the upper and lower net 6, 8, with the attachment points 18 formed by the rhombus-corners 18 substantially transverse to the direction of the row 12.

The solar units 2 hanging between the nets 6, 8 are aimed directly towards the sun at all times (see figures 25 8, 11 and 14). In the shown embodiment, every solar unit 2 contains a parabolic mirror surface 58 that reflects and concentrates the sunlight 46 into a single focal point. In this focal point, a photovoltaic solar cell 48 is mounted that generates electricity (figure 18).

30 To cool the cell from the high intensity sunlight, a cooling fluid 60 is moving around passing the photovoltaic solar cell 48 (figure 19). The cooling fluid 60 is subsequently moved to the backside of the mirror 58, where 13 it is cooled. The backside of the mirror 58 is always in the shade because the unit is aimed at the sun. Thus it is a relatively cold place. Also, it has the same size of the mirror 58, making the heat generating surface (mirror 58) 5 and the heat dissipating surface (backside of mirror 58) equally large.

The cooling fluid 60 moves to the backside by natural convection. The cooling fluid 60 is heated in the focal point by the sunrays. Hot fluid weighs less and moves 10 up. This causes a circulation where the cooled fluid from the backside moves to the focal point again. Because the temperatures in the system will be relatively low, the solar units 2 can be made out of plastic.

Although they show preferred embodiments of the 15 invention, the above described embodiments are intended only to illustrate the invention and not to limit in any way the scope of the invention.

It is noted that the invention is not restricted to the parabolic solar units 2 as shown, but that the system 20 is also applicable to aim flat panels with photovoltaic cells arranged on the surface thereof towards the sun.

Although the embodiment shown in the figures comprises a net structure arranged in a substantially lying plane, also other plane orientations (e.g. a standing plane) 25 are possible with the solar energy system according to the invention .

It is particularly noted that the skilled person can combine technical measures of the different embodiments. The scope of the invention is therefore defined solely by 30 the following claims.

14

CLAUSES

1. Solar energy system (1), comprising: - a plurality of solar units (2); 5 - suspension means (4) for suspending the plurality of solar units, said suspension means comprising an upper net (6) and a lower net (8) oriented parallel in a plane, a distance existing therebetween; - wherein at least two drive means (10) are 10 arranged to the suspension means (4) such that the upper and lower net (6, 8) are moveable relative to each other in the plane by the drive means (10); and - wherein every solar unit (2) is arranged to both the upper and the lower net (6, 8) such that the orientation 15 of the solar units (2) is adjustable via the drive means driving the suspension means.

2. Solar energy system according to clause 1, wherein: 20 - the upper and lower net (6, 8) are substantially identical and each net comprises a plurality of rows (12), each row comprising an array of rhombuses (14); - each rhombus comprises two rhombus-corners (16) substantially oriented in the longitudinal direction of the 25 row, and two rhombus-corners (18) substantially transverse to the longitudinal direction of the row; and - the solar units (2) are arranged to the rhombus-corners (18) that are substantially transverse to the longitudinal direction of the row.

30 15 3. Solar energy system according to clause 1 or 2, wherein : - the upper and lower net (6, 8) are quadrangular; and 5 - the at least two drive means (10) are arranged to adjacent corner pairs (20, 22) of the upper and lower net (6, 8) .

4. Solar energy system according to clause 2 or 3, 10 wherein rhombus-corners (16) that are substantially oriented in the longitudinal direction of the rows (12) of rhombuses (14) are connected by wires (24), thereby forming a web structure in the plane of the net (6, 8).

15 5. Solar energy system according to any of the foregoing clauses, wherein: - the drive means (10) comprise or are driveably connected to a rigid spacing element (26) to which both the upper and lower net (6, 8) are arranged; and 20 - the corner of the net opposite the corner of the net where the driveable rigid spacing element (26) is arranged comprises a further rigid spacing element (28) that is pivotably arranged at a pivot point (34) substantially halfway between the upper and lower net (6, 8) attachment 25 points (18, 20).

6. Solar energy system according to clause 5, wherein: - the drivable rigid spacing element (12) and the 30 pivotably arranged rigid spacing element (28) in the opposite corner are oriented parallel, such that the rigid spacing elements (12, 14) arranged between the corners of 16 the upper and lower net (6, 8), together with the upper and lower net (6, 8) define a parallelogram-shape.

7. Solar energy system according to any of the 5 foregoing clauses, further comprising tensioning members (30) arranged between support members (36) forming the foundation of the solar energy system, and the pivot points (32, 34) of the rigid spacing elements (26, 28), said pivot points (32, 34) being located substantially halfway between 10 the upper and lower net (6, 8) attachment points (18, 20).

8. Solar energy system according to any of the foregoing clauses, wherein the edges of the upper and/or lower net (6, 8) are provided with a main suspender cable 15 (38) that is suspended in a substantially parabolic shape between the net corners (20, 22).

9. Method for simultaneously adjusting a plurality of solar units within a solar energy system according to any 20 of clauses 1-8, comprising the step of driving the drive means (10) arranged to the suspension means (4), thereby moving the upper and lower net (6, 8) of the suspension means (4) relative to each other in their plane, and thereby adjusting the orientation of the solar units (2) arranged 25 between the upper and the lower net (6, 8) .

10. Solar energy system according to any of the clauses 1-8, further comprising control means configured for adjusting the plurality of solar units (2) according to the 30 method of clause 9.

Claims

A solar energy system, comprising: - a number of solar units; 5. suspension means for suspending the number of solar units, the suspension means comprising an upper net and a lower net which are oriented in parallel in a plane and with a distance between them; - wherein at least two drive means are arranged on the suspension means such that the top net and the bottom net are movable in the plane relative to each other by the drive means; and - wherein each solar unit is arranged on both the upper net and the lower net such that the orientation of the solar units is adjustable via the drive means that drive the suspension means.

A solar energy system according to claim 1, wherein: 20. the upper and lower networks are substantially identical and each network comprises a number of rows, each row comprising a succession of diamond shapes; - each pane comprising two pane angles that are substantially oriented in the longitudinal direction of the row, and two pane angles that are oriented substantially transversely of the longitudinal direction of the row; and - the solar units are arranged at the window angles which are oriented substantially transversely to the longitudinal direction of the row. 30

Solar energy system according to claim 1 or 2, wherein: the upper and lower networks are quadrangular; and - the at least two drive means are arranged on adjacent corner pairs of the upper and lower net.

4. Solar energy system according to claim 2 or 3, wherein window angles which are substantially oriented in the longitudinal direction of the row of windows are connected to wires, thereby forming a web structure in the plane of the network.

5. Solar energy system as claimed in any of the foregoing claims, wherein: - the drive means comprise or are connected to a rigid spacer element to which both the upper net and the lower net are arranged; and - the angle of the net opposite the angle of the net where the drivable rigid spacer element is arranged comprises a further rigid spacer element which is pivotally arranged at a pivot point which is substantially halfway between the attachment points of the upper net and lower net. 25

6. Solar energy system according to claim 5, wherein: - the drivable rigid spacer element and the hinge rigid spacer element arranged in the opposite angle are oriented in parallel, such that the rigid spacer elements arranged between the corners of the upper net and the lower net, together define a parallelogram shape with the upper and lower net.

7. Solar energy system as claimed in any of the foregoing claims, further comprising tensioning members arranged between support members forming the foundation of the solar energy system, and the pivot points of the rigid spacer elements, said pivot points being substantially halfway the fixing points of the upper and lower net.

Solar energy system according to one of the preceding claims, wherein the edges of the upper net and / or the lower net are provided with a main suspension cable which is suspended between the corners of the net in a substantially parabolic shape. 15

9. Method for simultaneously adjusting a number of solar units within a solar energy system according to any of claims 1-8, comprising the step of driving the drive means arranged on the suspension means, relative therewith moving the upper net and lower net of the suspension means relative to each other in their plane, and thereby adjusting the orientation of the solar units arranged between the upper net and lower net. 25

10. Solar energy system according to any of claims 1-8, further comprising control means adapted to adjust the number of solar units according to the method of claim 9. 30