AN IMPROVED SOLAR POWER STATION

Technical Field

The present disclosure relates to an improved solar power station having the features of the preamble of claim 1.

Background Art

Solar power stations of this type are well known. They are used to increase the annual output e.g. by 30% with respect to solar stations in which the solar devices are immovable.

Document EP1925891B9 discloses a solar power station

comprising: at least one solar device configured to generate power from solar energy; at least one space lattice

configuration having framework members and node connectors; at least one foundation having a bearing plane. The solar device is connected to the space lattice configuration; the space lattice configuration is configured to rotate, with respect the foundation, about just one axis, which is perpendicular to the bearing plane; the foundation comprises a ring, the bearing plane comprising the top of the ring.

The framework members of the space lattice configuration of document EP1925891B9 are interconnected at their ends through the node connectors in a pattern that consists of at least one semi-octahedron, at least one tetrahedron, and at least one octahedron. The space lattice configuration further comprises: at least one cuboctahedron; at least one

semi-cuboctahedron . Notwithstanding the many advantages of a solar power station of this type, the need for further decreasing its

construction cost as well as further increasing its annual output, thus making it more competitive, still exists.

Document WO2015155792A1 discloses a structure for supporting solar panels, which comprises a space frame structure and a foundation. The space frame structure is configured with interconnected framework members, which can carry

predominantly axial forces. The foundation comprises at least two rings, and piles, wherein the rings are fixed to the piles. The rings are curved beams or rails. The foundation has a bearing plane, which comprises the top of said rings, and a central bearing or node. The space frame structure bears on the bearing plane and rotates, with respect to the foundation, about just one axis which is perpendicular to the bearing plane and passes through the central bearing or node.

Document WO2015095424A1 discloses a foldable system for cleaning a reflector dish of a dish-based solar power

generation system. The primary structure of the reflector comprises a rim with a central hub, and at least one spoke radiating from the hub and being connected to the rim. Like a bicycle wheel, the connection of the spoke to the rim is made through adjustable tensioners.

Document US20140216440A1 discloses a tracker support system for solar collectors, which, in a particular embodiment, comprises a space frame structure, a triangular frame, and a foundation. The space frame structure is fixed to the

triangular frame. The triangular frame is formed by three beams that are identical and connected in pairs. The

foundation comprises a ring gear and piles, the ring gear being fixed to the piles, and the teeth of the ring gear being formed on the outer perimeter of the ring. Rolling members, in particular of the wheel type, are mounted at each corner of the triangular frame, wherein the rolling members bear on a horizontal roll band provided on the inner

perimeter of the ring, such that the triangular frame rests on that circular roll band which is integrated into the ring and thus pivot around a vertical axis of rotation.

Document GR1008021 discloses a helical pile having a tapered lead part, a shaft, and a pile cap. The tapered lead part, which is configured to enter the ground when rotated, has a helical flat bar or plate welded on it.

The above mentioned helical pile is manufactured from a single piece of pipe having at least two symmetrical

longitudinal slots at one of its end parts. The tapered lead part is formed by radial cold forging of the end part having the slots. According to this process, the end part having the slots is axially forced and rotated between two radially moving anvils or dies. The resulting tapered lead part is characterized by a cross section which comprises at least two Archimedean spirals, the cross sectional area of the tapered lead part being constant along its length and approximately equal to the cross sectional area of the shaft. This type of helical pile is suitable for both hard and soft soils, wherein for soft soils the width of the helical flat bar or plate is increased.

Document US4674244 discloses an improved roof construction for generating power from solar energy comprising a

substantially flat, horizontal roof substrate and a plurality of parallel structures extending above the substrate. Each structure has two inclined surfaces S and Si . Solar devices are fixed to portion of surfaces S ; and reflecting devices to portion of surfaces SI , wherein the reflecting devices are configured to reflect solar radiation the solar devices. Disclosure of Invention

The aims of the present invention were:

- to solve the problem of lack of structural integrity in solar power stations of prior art having the features the preamble of claim 1;

- to make possible the realization of large scale solar power stations having solar devices, large space lattice configurations, and foundations, wherein the space lattice configurations rotate with respect to the

foundations, which are capable of resisting high wind actions, e.g. during a violent storm, and which require less amount of material per kW of installed moving solar devices;

- to provide a solar power station having space lattice configurations and foundations, which are susceptible to the so called open-ended type of industrialization that offers the economic advantage of an industrial mass production technique combined with a high degree of flexibility;

- to provide a solar power station with an environmental friendly or sustainable way of construction which

reduces: energy consumption, amount of material, erection time, on site labour costs, and waste and dust on site.

These aims are achieved by an improved solar power station having the features of the characterizing part of claim 1. Additional advantages are achieved by the features of the dependent claims 2-12.

The improved solar power station according to the present invention comprises at least one space lattice configuration having framework members and node connectors, wherein the framework members are interconnected at their ends through the node connectors in a pattern that consists of at least one semi-cuboctahedron (½CO) and at least one

semi-octahedron (½0) .

As has been illustrated in document EP1925891B9, the

semi-cuboctahedron (½CO) and the semi-octahedron (½0) , which are configured with framework members and node connectors, are polyhedra whose configuration does not have structural integrity. Similarly, the space lattice configuration which consists of semi-cuboctahedrons (½CO) and semi-octahedrons (½0) in a face to face relationship does not have structural integrity.

Notwithstanding the advantage of relatively small number of framework members and node connectors of this space lattice configuration, as well as the convenience in incorporating solar devices within the space lattice, the problem of lack of structural integrity of this configuration still needs to be solved.

This is achieved by:

- the foundation which further comprises: a central hub, at least three pre-tensioned spokes, at least three piles, wherein: the hub is fixed to the spokes, the spokes are connected to the ring, the ring is fixed to the piles, and wherein said spokes are configured to restrain said hub with respect to said ring;

- the space lattice configuration which is rotatably mounted to said hub, in a manner that allows rotation, the axis of rotation passing through the centre of said hub;

- the at least one restraining device, which is configured to restrain said space lattice configuration with respect to said ring, wherein: the restraining device is fixed to said space lattice configuration, bears on the bearing plane, and is connected to said ring. In this way certain degrees of freedom in the configuration are restrained and the space lattice acquires structural integrity and becomes a space lattice structure, capable of resisting high wind actions.

The at least three pre-tensioned spokes comprise pre-tensioning means so as to enable pre-tensioning. The pre-tensioning means further comprise radial distance regulating means.

The space lattice configuration further comprises an axle configured to rotate within the hub, the axle being fixed to the space lattice configuration. The provision of the axle allows for the even distribution of the horizontal wind actions to the piles, particularly when the space lattice configuration is rotatably released. In particular, this is achieved by the at least three pre-tensioned spokes which being under tension, and restraining the hub with respect to the ring, can transfer horizontal wind actions in all

directions from the hub to the ring, and to the piles.

In a preferred embodiment, the above mentioned restraining device comprises a structural bearing configured to restrain the space lattice configuration with respect to the ring: a) in the tangential direction, b) in the radial direction, c) parallel to the axis of rotation.

In another embodiment, the restraining device is configured to rotatably release the space lattice configuration with respect to the ring, by removing the restraint in the

tangential direction.

In still another embodiment, the restraining device is configured to restrain the space lattice configuration parallel to the axis of rotation, by removing the restraints both in the tangential and in the radial direction.

In the above embodiments, the restraining device preferably comprises a hydraulic structural bearing actuated by fluid pressure, the fluid flow being controlled remotely using solenoid valves.

In an improved embodiment, the ring comprises a curved beam. Also, the ring comprises an internal gear having a formed flat bar comprising the teeth of the internal gear, the formed flat bar being fixed to the ring. This improved embodiment further comprises a motor driven pinion configured to rotate the space lattice configuration when operated, the motor driven pinion being in mesh with the internal gear. Preferably, the motor driven pinion comprises a hydraulic motor driven pinion.

In another improved embodiment, the incorporation of

reflecting devices, which are configured to reflect solar radiation to the solar devices, further increases the annual output of the solar power station according to the present invention, e.g. by at Least another 30%, depending on the location of the solar power station and the technology of the reflecting devices, and thus making this improved solar power station quite competitive.

The adoption of the helical pile in the foundation provides an environmentally friendly way of construction, which assists in reducing erection time, on site labour costs, and waste and dust on site.

With the addition of the tetrahedron ( 27) the structural efficiency of the space lattice configuration is further improved, making possible the realization of reliable large scale solar power stations. Brief Description of Drawings

The invention will be further described, by way of example only, with reference to the accompanying drawings wherein like elements are numbered alike in the several figures:

Fig. 1 shows a diagrammatic three-dimensional view of an improved solar power station according to

the present invention.

Fig. 2 shows a space lattice configuration of

type ½CO + ½0, which is part of the space lattice configuration of Fig. 1.

Fig. 3 shows a plan view of the foundation of Fig. 1. Fig. 4 shows a sectional view of the foundation

of Fig. 1.

Fig. 5 shows a sectional view of a spoke-to-ring

and ring-to-pile connection detail of Fig. 1, and

a hydraulic motor driven pinion.

Fig. 6 shows a plan view detail of the internal

gear of Fig. 5.

Fig. 7 shows the elevational view of a restraining device of Fig. 1, comprising a hydraulic structural bearing actuated by fluid pressure.

Fig. 8 shows a space lattice configuration of type

½co + ½0 + T.

Best Mode(s) for Carrying Out the Invention Hereinafter, the best mode contemplated for carrying out the present invention is described in detail.

The improved solar power station of Fig. 1 comprises at least one solar device 2 configured to generate power from solar energy, at least one space lattice configuration 4 , and at least foundation 6 having a bearing plane 5. The solar device 2 is firmly or rotationally connected to the space lattice configuration 4 through a structure 3 on which the solar device 2 is fixed. The space lattice configuration 4 has framework members 9 and node connectors 1, wherein the framework members 9 are interconnected at their ends through the node connectors 1, e.g. according to document GR1004187, in a pattern that consists of at least one

semi-cuboctahedron ½CO and at least one semi-octahedron ½0.

Fig. 2 shows a semi-cuboctahedron ½CO and a semi-octahedron ½0 assembled together in a face to face relationship, thus forming a space lattice configuration 4 of type ½CO + ½0. In this configuration the framework members 9 are the edges, and the node connectors 1 are the vertexes of the polyhedrons.

The faces of the polyhedrons which are configured in this manner are left to be imagined. The semi-cuboctahedron ½CO of Fig. 2 has two parallel unequal square faces connected by eight isosceles triangular faces, so that there are three triangular and one square face at each vertex, the framework members of the larger square face having a length equal to the length of the framework members of the smaller square face multiplied by square root of two. The height of such a semi-cuboctahedron ½CO can always be adjusted so that the four triangular faces which have a common framework member with the smaller square face become equilateral, the four triangular faces which have a common framework member with the larger square face becoming right-angled isosceles. The semi-octahedron ½0 of Fig. 2 is a right regular pyramid having one square face, and four isosceles triangular faces. The height of such a semi-octahedron ½0 can also be adjusted so that the four isosceles triangular faces become

equilateral, the square face of the semi-octahedron ½0 having a common framework member with the smaller square face of the semi-cuboctahedron ½CO. The space lattice configuration of Fig. 2 is part of space lattice configuration 4 of Fig. 1.

Referring again to Fig. 1, the space lattice configuration 4 is configured to rotate with respect to the foundation 6 about just one axis 7 which is perpendicular to the bearing plane 5.

The foundation 6 comprises a ring 18, wherein the bearing plane 5 comprises the top of the ring 18.

The foundation 6 of the improved solar power station of

Fig. 1 further comprises: a central hub 20, at least three pre-tensioned spokes 22 radiating from the central hub 20, and at least three piles 16, wherein: the hub 20 is fixed to the spokes 22, the spokes 22 are connected to the ring 18, the ring 18 is fixed to the piles 16.

The at least three pre-tensioned spokes 22 are configured to restrain said hub 20 with respect to said ring 18, wherein the pre-tensioned spokes 22 comprise pre-tensioning means 14.

The space lattice configuration 4 is rotatably mounted to said hub 20, in a manner that allows rotation about the just one axis of rotation 7, wherein the just one axis of

rotation 7 passes through the centre of said hub 20.

The improved solar power station of Fig. 1 further comprises at least one restraining device 15 which is configured to restrain said space lattice configuration 4 with respect to said ring 18, wherein the restraining device 15 is fixed to said space lattice configuration 4, bears on the bearing plane 5, and is connected to said ring 18.

The space lattice configuration 4 of the improved solar power station of Fig. 1 further comprises an axle 24 which is configured to rotate within the hub 20, the axle 24 being fixed to the space lattice configuration 4 through

interconnecting framework members 23.

Figs. 3-6 show an embodiment of the foundation 6, and Fig. 7 an embodiment of the restraining device 15 of the improved solar power station of Fig. 1.

In a preferred embodiment, the above mentioned restraining device 15 comprises a structural bearing 15 configured to restrain the space lattice configuration 4 with respect to the ring 18: a) in the tangential direction, b) in the radial direction, c) parallel to the axis of rotation 7.

In another preferred embodiment, the restraining device 15 comprises a structural bearing 15 configured to rotatably release the space lattice configuration 4 with respect to the ring 18, by removing the restraint in the tangential

direction .

In the above embodiments, the restraining device 15

preferably comprises a hydraulic structural bearing 15 which is actuated by fluid pressure. The fluid flow to the

restraining devices 15 of this type is controlled remotely through a central controlling unit using solenoid valves.

In an improved embodiment, the ring 18 comprises curved beam 21. In addition, the ring 18 further comprises an internal gear 18, having a formed flat bar 17 comprising the teeth of the internal gear 18, the formed flat bar 17 being fixed on the inner side of the ring 18. The resulting

internal gear 18 has a reduced manufacturing cost. In this embodiment the improved solar power station of Fig. 1 further comprises a motor driven pinion 19 configured to rotate said space lattice configuration 4 about said axis 7 when operated, wherein the motor driven pinion 19 is in mesh with the internal gear 18. Preferably, the motor driven pinion 19 comprises a hydraulic motor driven pinion 19.

The above mentioned pre-tensioning means 14 further comprise radial distance regulating means 14, which assist in

minimizing the deviations from the pure cyclic geometry in the above mentioned internal gear 18, thus allowing for the smooth operation of the motor driven pinion 19.

In another improved embodiment, the improved solar power station of Fig. 1 further comprises at least one reflecting device 25 which is configured to reflect solar radiation to said at least one solar device 2. The reflecting device 25 is either firmly or rotationally connected to the space lattice configuration 4 through a structure 3 on which the reflecting device 25 is fixed.

The at least three piles 16 of the foundation 6 of the improved solar power station of Fig. 1, further comprise helical piles 16, e.g. according to document GR1008021, thus providing an environmental friendly way of construction for the foundation 6.

Fig. 8 shows a space lattice configuration 4 which consists of one semi-cuboctahedron ½CO, two semi-octahedrons ½0, and one tetrahedron T , in a face to face relationship. The first semi-octahedron ½0 has a common triangular face with the semi-cuboctahedron ½CO, the second semi-octahedron ½0 has a common square face with the first semi-octahedron ½0, and the tetrahedron T has a common triangular face with the second semi-octahedron ½0. In this embodiment the common triangular faces are equal isosceles, the tetrahedron T having four equal isosceles triangular faces. The height of the

semi-octahedrons ½0 can be adjusted so that the common equal isosceles triangular faces become equilateral, and then the tetrahedron T becomes a regular tetrahedron having four equilateral triangular faces. Although the invention has been explained in relation to its preferred embodiment (s) as mentioned above, it is to be understood that many other possible modifications and variations can be made without departing from the scope of the present invention. It is, therefore, contemplated that the appended claim or claims will cover such modifications and variations that fall within the true scope of the invention .