WO2022220679A1

WO2022220679A1 - System for generating electrical energy

Info

Publication number: WO2022220679A1
Application number: PCT/NL2022/050202
Authority: WO
Inventors: Johan Jelle Solco Bakker
Original assignee: Eqa Projects B.V.
Priority date: 2021-04-13
Filing date: 2022-04-12
Publication date: 2022-10-20
Also published as: NL2027960B1; EP4324091A1

Abstract

A system for generating electrical energy comprising a plurality of solar panels (5) and at least one frame (6) on which the solar panels are arranged in rows. The system is displaceable back and forth in the vertical direction between an operating position, in which the system floats on water and the solar panels extend above the water, and a safe position, in which the system is at least partially immersed in the water and the solar panels being under water. The system further comprises a displacement device for displacing between operating and safe position, the displacement device comprising at least one immersion body (31) with an interior space connected to the frame for joint displacement in vertical direction. The immersion device further comprises a supply device and a discharge device for supplying and discharging water from the interior space of the immersion body to increase the floating ability of the system.

Description

Title: System for generating electrical energy.

Description:

The present invention relates to a system for generating electrical energy. More specifically, the invention relates to a system in which use is made of solar panels which are provided on a frame and float on the water of a body of water such as a lake, which system may temporarily be made to sink such that the solar panels extend at least largely under water. This may for example be desirable when rough weather conditions are expected. Such a system is described in French publication FR 3028014 A1. This system comprises rows of reclined photovoltaic modules which, in normal operation, are each kept floating with the aid of a layer of polyurethane foam which is provided under each module. In normal operation, the modules are also kept floating by a plastics pipe which meanders under a number of modules situated next to one another in such a way that the pipe runs under, and thus supports, each module at two or four positions. The pipe has an internal volume and is filled with air during normal operation. The extent to which the system floats is determined by Archimedes’ principle. In general, this principle states for water that the upward force, also referred to as buoyant force, acting on a body in water is equal to the weight of the amount of water displaced by said body. The last-mentioned weight is equal to the volume of the body situated under water multiplied by the density of water (which is 1000 kg/m³). In order to remain floating, the upward force has to be equal to the weight of the body. In order to make the system according to FR 3028014 A1 sink, the internal volume of the pipe is filled with water, as a result of which the weight of the system increases, and the system therefore has to float lower in the water in order to thus displace more water and to increase the upward force to the increased weight of the system. If the supply of water to the internal volume of the pipe causes the weight of the system to become greater than the maximum upward force, that is to say the product of the total volume of the system and 1000 kg/m³, then the system will disappear, that is to say sink, completely under water.

A major drawback of the system described in FR 3028014 A1 is that the structural cohesion between the various modules is effected by way of the aforementioned meandering pipe. This pipe therefore serves both as a frame for keeping the modules at desired positions with respect to one another and as a means for making the modules sink. The length of the pipe will have to be relatively great, specifically approximately two or even four times the sum of the lengths of the rows in which the modules are provided. With respect to this system, and also with respect to the installation of such a system, it is unclear how a practical embodiment and application could be provided in which all of the structural and functional requirements that such a floating system has to meet are satisfied at a commercially justifiable price, especially if the system were to comprise hundreds or even thousands of solar panels arranged in rows. The fact that it is often desirable for solar panels to be immersed relatively quickly also plays a role in this case, in particular due to the fact that, for example, weather conditions that make the immersing of solar panels advisable may become known only shortly before these weather conditions actually occur. In addition, the amount of energy generated by the system will be limited more as the duration of the immersion of the solar panels increases because the solar panels are not available to generate energy during the immersion.

The present invention aims to provide a solution to the aforementioned drawbacks and, to this end, provides a system as claimed in claim 1. The invention is in this case based on the inventive understanding that integrating the functions of, on the one hand, being able to make the system sink and float up again and of, on the other hand, ensuring the structural cohesion between the various modules into the meandering pipe according to FR 3028014 is actually not efficient, but that it is in fact advantageous for these functionalities to be embodied in different components of the system. Therefore, the system according to the invention comprises, on the one hand, a frame which ensures good support of the solar panels and good structural cohesion between the solar panels, and, on the other hand, at least one immersion body which makes it possible to make the system sink temporarily. This uncoupling of functions makes it possible for the embodiment and dimensioning of the frame on the one hand and of the at least one immersion body on the other hand to be optimally matched to their respective functions, meaning that ultimately the system can be produced at a lower cost and the desired functionality can be implemented. The invention is also based on the inventive understanding that the ratio of the total length of the meandering pipe according to FR 3028014 to the number of modules will be relatively high in a practical embodiment in which hundreds or even thousands of solar panels are used, as a result of which a relatively large amount of time and/or energy will be required to completely fill the pipe, and/or that a first portion of the modules of the system has already sunk or is starting to float again while another portion is not yet sinking or starting to float. This intricate arrangement may lead to undesired structural stresses in the pipe itself and thus increased susceptibility to fracture. The aforementioned distinction between the frame on the one hand and the at least one immersion body on the other hand, as a characteristic feature for the invention, also offers parameters for solving these problems.

In one embodiment, the at least one immersion body comprises an immersion body which comprises an elongate first immersion body part and at least one, preferably more than one, elongate second immersion body part/immersion body parts which branches/branch off from the first immersion body part. The material of the immersion body can thus be used efficiently so as to extend over a relatively large part of the surface of the frame or at least substantially over the entire surface of the frame, and the cost can be limited.

If the at least one second immersion body part branches off at right angles from the first immersion body part, it is possible for the first immersion body part and the at least one second immersion body part to follow the directions of the rows of the solar panels, which may offer structural advantages.

The efficiency with which material of an immersion body may be utilized to perform the function of the immersion body, specifically to make the system sink and float again with the aid of the immersion body, and thus the cost of the system may also benefit if the at least one immersion body comprises multiple rows of elongate immersion body parts which extend parallel to each other and to the rows of solar panels, wherein the number of rows of immersion body parts is smaller than the number of rows of the solar panels, in particular if the number of rows of immersion body parts is smaller than half the number of rows of the solar panels. The immersion body parts mentioned in this paragraph may be the second immersion body parts mentioned above.

The aforementioned efficiency may also be increased if the at least one immersion body comprises a number of elongate immersion body parts which together determine at least 90% of the total volume of the at least one immersion body, and of which the sum of the lengths of the individual immersion body parts is smaller than the sum, preferably half the sum, of the lengths of the rows of solar panels.

In a further embodiment, the at least one immersion body comprises multiple sets of associated elongate immersion body parts, which immersion body parts belonging to a set extend parallel to each other and to the rows of solar panels within the width of a row of solar panels, wherein the number of sets of immersion body parts is smaller than the number of rows of solar panels. The width of the row of solar panels corresponds to the center-to-center distance between two adjacent rows of solar panels. In such an embodiment, the individual immersion body parts may be of smaller dimensions.

A practical embodiment may be achieved if the at least one immersion body is substantially pipe-shaped, at least in the safe position. The cross section of this pipe shape may for example be round or rectangular, such as square.

If the pipe shape has a cross section whose internal surface area is between 700 cm² and 5000 cm², preferably between 1250 cm² and 2800 cm², which limit values correspond in the case of round cross sections to inside diameters of between about 30 cm and 80 cm, respectively between about 40 and 60 cm, it is possible for water to be supplied to or discharged from the interior space of the at least one immersion body relatively quickly such that the vertical displacement between the operating position and the safe position may also be implemented relatively quickly. If sets of immersion body parts are used as mentioned above, it is possible to use pipes having smaller diameters, such as between 15 cm and 30 cm.

In particular if the at least one immersion body extends at least partially under water in the operating position, an embodiment in which the at least one immersion body has a dimensionally stable wall which surrounds the interior space may offer the advantage that the at least one immersion body may contribute significantly to the upward force that acts on the system in accordance with Archimedes’ principle.

Alternatively, it is also possible within the context of the invention for the at least one immersion body to have a flexible wall which surrounds the associated interior space. Such an embodiment may be relatively lightweight and also quite flexible such that the system may deform elastically, which may be desirable owing to wave action or when the system is being immersed and made to float again.

In a practical embodiment, the at least one frame comprises pipes. These pipes may be provided in a more intricate manner than the way in which the at least one immersion body is shaped. With the aid of pipes, it is possible to provide the frame with the desired volume in a relatively simple manner, in order for the pipes to thus make a desired contribution to the floating ability of the system. From the standpoint that the frame has no function for implementing vertical displacement of the system, in a further embodiment the pipes are configured to make it impossible for water to enter the respective spaces of the pipes. This may for example be effected by coupling ends of pipes to one another such that they together form an endless path or by permanently closing off ends of pipes. Furthermore, the pipes of the frame may be provided in such a way that respective interior spaces thereof cannot communicate with one other, with the result that only a limited portion of the total volume of the interior spaces may be filled with water in the event of a leak. This may be effected by compartmentalizing interior spaces using partitions. Alternatively, use may also be made of a plurality of individual pipes or individual pipe systems whose closed interior spaces cannot communicate with one another. The number of individual pipes or individual pipe systems that belong to the frame may for example be equal to the number of solar panels, but may also be less than the number of solar panels, for example may be between 50% and 5% of the number of solar panels, which may benefit the structural simplicity of the frame.

In a practical embodiment, the pipes also have a cross section whose internal surface area is between 20 cm² and 300 cm², which limit values correspond in the case of round cross sections to inside diameters of between about 5 cm and 20 cm.

A favorable embodiment may be achieved if the pipes are made of fiber- reinforced material. Such materials may be relatively lightweight.

The system preferably comprises a limiting device for limiting the extent to which the system may sink in the safe position. On the one hand, when using such an embodiment, it is possible to prevent physical contact between the system and the bottom of a body of water, which contact could lead to damage. On the other hand, such an embodiment may also limit the amount of time involved for displacing the system from the safe position to the operating position.

A reliable embodiment may be achieved if the limiting device comprises buoy bodies and tension elements connected to the buoy bodies, which tension elements, in the safe position, act between the at least one frame and the buoy bodies and are configured to prevent the immersion bodies, together with the at least one frame and the solar panels, from being immersed further in the safe position of the system when the system has sunk over a determined immersion length. In this case, the tension elements may be flexible, such as cables, or rigid, such as rods. The tension elements may also be elastic such that they do not have a fixed length. Tension elements of elastic embodiment may in particular be advantageous when using buoy bodies, as will be discussed further below. The elasticity of the tension elements may be advantageously utilized due to the fact that, if the system is in the safe position, in the event of great wave action, the frame will not have to follow the vertical displacement of the buoy bodies to the same extent.

It may be particularly efficient if the number of buoy bodies is smaller than the number of solar panels, preferably smaller than half the number of solar panels.

A practical embodiment, when using the system, may be achieved if the supply device comprises at least one water pump for pumping water into the interior space of the at least one immersion body. By supplying water to the interior space of the at least one immersion body, the system can be immersed. Rapid supply of water and therefore rapid immersion in water is made possible by a pump.

The supply of water to the interior space may also be achieved or accelerated if the supply device comprises at least one air pump for pumping air out of the interior space of the at least one immersion body. The reduced pressure that may thus be created in the interior space makes the supply of water easier.

If the discharge device comprises at least one water pump for pumping water out of the interior space of the at least one immersion body, the system may be moved in the vertical direction from the safe position to the operating position in a practical and rapid manner.

The discharge device may also comprise at least one air pump for pumping air into the interior space of the at least one immersion body, as a result of which water can be displaced out of the interior space, for example via openings in the underside of the at least one immersion body. In such an embodiment, the system may also be provided with an air valve via which, in the open position of the air valve, air can escape from the interior space and which, in a closed position of the air valve, actually prevents air from being able to escape from the interior space.

In general, it may be advantageous if the weight of the solar panels is equal to at least 50%, preferably at least 80%, of the collective weight. The weight of the solar panels should also be considered to include the weight of supports and/or braces via which the solar panels rest on the frame. In a specific embodiment, at least in the operating position, the at least one immersion body extends at least partially, preferably largely, further preferably completely, under water. In the operating position, the immersion body can thus contribute to the upward force, and the system is, as it were, drawn downward during the displacement from the operating position to the safe position on account of the at least one immersion body being filled with water, as a result of which said displacement can take place in a relatively stable manner with limited risk of the system tilting.

In the aforementioned specific embodiment, the volume of the at least one frame is preferably equal to at least 80%, preferably at least 90%, of the collective volume of the system. Said percentages are indicative of the upward force acting on the system on account of the at least one frame.

In the operating position, the volume of the at least one immersion body, that is to say including the interior space thereof, regardless of whether or not this is (partially) filled with water, is at most 20%, preferably at most 10%, of the collective volume of the system.

In a very practical embodiment, the supply device comprises at least one shut-off valve which, in an open position, allows water to pass from outside an immersion body to the interior space of the at least one immersion body and, in a closed position, blocks such a passage of water. Bringing the at least one shut-off valve into the open position makes it possible for water to be autonomously supplied to the interior space of the at least one immersion body in order to displace the system from the operating position to the safe position. In order to facilitate the supply of water to the interior space of the at least one immersion body such that it is distributed uniformly over the surface of the frame, and thus to prevent the magnitude of possible bending stresses in the frame, it may be preferable to embody the supply device with a number of shut-off valves which are preferably distributed uniformly (in plan view) over the surface of the frame.

In order to be able to discharge water from the interior space of the at least one immersion body, it may be preferable if the system comprises at least one drainage line which is connected at one end to the interior space of the at least one immersion body and, in the safe position, opens out at an opposite end above water. Water can then be discharged via this at least one drainage line. It may also be preferable for the system to comprise at least one ventilation line which is connected at one end to the interior space of the at least one immersion body and, in the safe position, opens out at an opposite end above water. Air can thus escape from the interior space in order to make space for water, and water is prevented from being able to flow into the interior space via the at least one ventilation line.

At certain points in time, it may be desirable to, proceeding from the operating position, temporarily increase the upward force such that the system comes to lie higher in the water and/or may be loaded to a greater extent. This may be relevant, for example, if personnel are working on the frame or in the case of snowfall or the formation of ice. The possibility of increasing the upward force may be provided if, in the operating position, up to at least 5% of the interior space of the at least one immersion body is filled with water. The upward force can be increased in a simple manner by discharging some or all of that water from the interior space.

In another specific embodiment of the system, at least in the operating position, the at least one immersion body or at least the interior space thereof extends completely above water. It is thus possible to obtain a system that inherently cannot sink any lower than a position in which the top side of the system, more specifically of the at least one immersion body, is still just touching the surface of the water of the body of water. Separate provisions for limiting the extent of sinking may thus be redundant. In addition, such a configuration allows the immersion bodies to be easily inspected, as a result of which maintenance is relatively easy.

In one embodiment of the specific embodiment according to the previous paragraph, the volume of the at least one frame is equal to at least 80%, preferably at least 90%, of the collective volume of the system.

In order to be able to achieve a situation in which the solar panels are completely under water in the safe position, it may be preferable that, at least in the safe position, top sides of the at least one immersion body are situated at the same level as or above the top sides of the solar panels.

Available space may be advantageously utilized if the at least one immersion body extends between adjacent rows of the solar panels. Adjacent rows should be understood to mean the situation in which the rows in question are situated directly next to one another without another row being situated between the adjacent rows. The invention will be explained in more detail below by means of the description of two embodiments, which are not to be interpreted as limiting to the scope of the invention, of systems according to the invention with reference to the following figures: figures 1 a and 1 b show isometric views of a first embodiment of a system according to the invention in the operating position and in the safe position, respectively; figures 2a and 2b show perpendicular horizontal views of the system according to the first embodiment in the operating position and in the safe position, respectively; figures 3a and 3b show details III in the respective figures 2a and 2b; figures 4a and 4b show details IV in the respective figures 2a and 2b; figures 5a and 5b show details V in the respective figures 2a and 2b; figure 6 shows an exploded illustration of the system according to the first embodiment; figure 7 shows an isometric view of a module that forms part of the system according to the first embodiment in the operating position; figure 8a shows detail VIII in figure 7; figure 8b shows detail VIII in figure 7 but in the safe position; figure 9 shows an exploded illustration of the module according to figure

7; figures 10a and 10b show isometric views of a second embodiment of a system according to the invention in the operating position and in the safe position, respectively; figures 11a and 11b show perpendicular views of the system according to the second embodiment in the operating position and in the safe position, respectively; figures 12a and 12b show details XII in the respective figures 11a and

1 1 b; figures 13a and 13b show details XIII in the respective figures 11a and

1 1 b; figures 14a and 14b show details XIV in the respective figures 11a and

1 1 b; figure 15 shows an exploded illustration of the system according to the second embodiment.

Figures 1a to 9 relate to a first embodiment of a system according to the invention. Insofar as the letters a or b are used in the numbering of these figures, these figures relate to an operating position of the system and a safe position of the system, respectively.

Figures 1a and 1b show a body of water 1 in which there is a floating solar park 2, which embodies a first embodiment of the system according to the invention. With reference to figures 6 to 9, too, the floating solar park 2 comprises a field 3 having solar panels 5 which are arranged in rows 4 and which are arranged at an angle in order to be optimally directed toward the sun. The solar panels 5 are supported by a frame 6 which comprises a framework of longitudinal beams 7 and transverse beams 8 made of plastics material, such as fiber-reinforced plastics material having a density of between 900 kg per m³ and 2000 kg per m³. The longitudinal beams 7 and transverse beams 8 define a regular pattern of boxes 9 and give the frame 6 the shape of a grid.

The frame 6 further comprises, per box 9, a pipe system 10 made of plastics material, such as fiber-reinforced plastics material also having a density of between 900 kg per m³ and 2000 kg per m³. Each pipe system 10 comprises two longitudinal pipes 11 and two transverse pipes 12, the ends of which are connected to one another via four elbow pipes 13 such that the longitudinal pipes 11 , transverse pipes 12 and elbow pipes 13 of each pipe system form a closed circuit. Each pipe system 10 has a rectangular shape, which follows the rectangular shape of the associated box 9. Each pipe system 10 is also connected to the box 9 within the plane of said box 9 in a manner that is not described in any more detail.

The diameter of the pipes 11 , 12 and 13 is between 25 mm and 150 mm. Instead of (hollow) pipes, use may also be made of solid floating bodies, for example having the shape of rectangular plates which are provided in the interior spaces of each box 9, said floating bodies being manufactured from a material, for example a foam-like material such as expanded polystyrene (EPS), whose density is lower than the density of water, for example lower than 50%, 25% or 10% of the density of water.

Above transverse beams 8 of adjacent boxes 9, said beams extending along one another, the frame 6 is also provided with gratings 14 which extend between adjacent rows 4 of the solar panels 5. In this embodiment, the frame 6 is constructed from frame modules 21 which each support four rows of four solar panels 5 and wherein the frame modules 21 are coupled to one another in order to thus give the frame 6 the shape of the field 3 of the solar panels 5. The solar park 2 comprises four buoy bodies 22 per frame module 21, that is to say per 16 solar panels 6, said buoy bodies each being embodied as plastics pipes whose ends are closed off and whose length is equal to the width b of the solar panels 5. Each buoy body 22 is provided between two adjacent solar panels 5 within a row 4. Tension cords 23, the ends of which extend downward, are wound over the two ends of each buoy body 22. Stop bodies 24 are provided at these respective ends of the tension cord 23. The tension cords 23 extend through holes in the transverse beam 8 at the location of the relevant end of buoy body 22. The stop bodies 24 are shaped and/or dimensioned in such a way that they do not fit through the last-mentioned holes. The tension cords 23 may be made of elastic material, or use may also be made of rigid tension elements such as tension rods instead of flexible tension cords 23.

Solar park 2 further comprises an immersion body 31 under the frame 6. The immersion body 31 is constructed from a number of pipes 32a to 35b. These pipes are manufactured from fiber-reinforced plastics material and have a diameter of between 300 mm and 800 mm and have a density of between 900 kg per m³ and 2000 kg per m³. The pipes 32a to 32d form a central pipe body, indicated by reference numeral 32. The pipes 33a to 35b branch off at right angles from this central pipe body 32, wherein the pipes 33a, 33b and 34a, 34b and 35a, 35b extend in line with one another and are provided on sides of the pipe body 32 that are situated opposite one another. The interior spaces of the pipes 32a to 35b are mutually directly connected to one another such that water can flow freely from the one interior space to an adjoining interior space. The free ends of the pipes 32a to 35b (except for pipes 32b, 32c which have no free ends) are sealed such that the interior spaces of the respective pipes 32a to 35b form a closed common space. The periphery 36 of the immersion body 31 , which periphery is obtained by connecting the free ends of said pipes 32a to 35b to one another, extend under the largest part of the surface of the field 3 of solar panels 4.

As will be apparent from table 1 below, up to 90% of the total volume V of solar park 2 is formed by the volume of frame 6. That on its own is not sufficient to keep solar park 2 floating in the operating position. The volume of immersion body 31 is equal to 7% of the total volume V of solar park 2. The floating ability, that is to say the upward force induced by (the volumes of) the frame 6 and the immersion body 31 , is sufficient to make solar park 2 float in the operating position. The immersion body 31 in this case supports the frame 6 at a number of discrete positions. The stiffness of the frame 6 ensures that the frame 6, in part under the influence of the weight of the field 3, does not deflect between these discrete positions, at least not to an undesirable extent.

Ball valves 37a, 37b, 37c are provided on the underside of the intersection points 40a, 40b, 40c of, respectively, pipes 32a, 33a, 33b, 32b and 32b, 34a, 34b, 32c and 32c, 35a, 35b, 32d. In addition, in the case of the central middle intersection point 40b, a pump 38 is also provided together with a drainage pipe 39 in the immediate vicinity of pump 38, a lower end of said drainage pipe being connected to the interior space of pipe 34b and the upper end of said drainage pipe, both in the operating position and in the safe position, above the water of the body of water 1, as will become even clearer below. The solar park 2 further comprises ventilation pipes 41 at free ends of pipes 32a to 35b, respective lower ends of said ventilation pipes also being connected to the interior spaces of the associated pipes 32a to 35b and the upper end of said ventilation pipes protruding, both in the operating position and in the safe position, above the water in the body of water 1. The immersion body 31 is connected, in a manner that is not shown in any more detail, to the frame 6 such that displacements of the frame 6 and of the immersion body 31 , and also of the solar panels 5, may take place exclusively in a joint manner.

Table 1 below applies to solar park 2.

The functioning of solar park 2 will be explained below partly on the basis of table 1, where the variable V is the total volume of the solar park 2 and where the variable X is the total mass of the solar park 2 in the operating position. The weight (in newtons) of the solar park is 9.8 times the mass (in kg) thereof.

The solar park 2 functions as follows: The starting point is the operating position, as illustrated in figures 1 to 9 insofar as the numbering of the figure is provided with the addition “a”, in which, in this example, there is no water inside the immersion body 31. It is apparent from table 1 that 98% of the total volume of solar park 2 is under water in the operating position. The remaining 2% is formed by the solar panels of the field 3 and equipment and provisions that are provided on the frame 6. The weight of field 3 determines up to 95% of the total weight of the solar park 2.

As soon as the solar park 2 is intended to be brought into the safe position, in which the solar panels 5 come to extend completely under the water surface of body of water 1 , the ball valves 37a, 37b, 37c are opened, as a result of which water from body of water 1 gains access to the common interior space of the immersion body 31. Due to the fact that the immersion body 31 thus fills with water, the weight of the solar park 2 becomes greater and the solar park 2 comes to lie continually lower in the water. From another standpoint, one could moreover also say that the volume of the water supplied to the interior space of the immersion body 31 is at the expense of the volume of the system and therefore of the upward force. During the supply of water to the interior space of the immersion body 31 , the ventilation pipes 41 offer air in the interior space of the immersion body 31 the possibility of escaping from this interior space.

At a certain point in time, the weight of the solar park 2 owing to the supply of water to the immersion body 31 is so great that the upward force that can be maximally generated by the solar park 2, which maximum upward force is directly related to the volume of the solar park 2, is not sufficiently great to keep the solar park 2 floating on the water of the body of water 1. It is precisely at that point in time that virtually the entire solar park 2, and in all cases including the field 3, comes to lie under water.

Shortly after this situation has been reached, the ball valves 37a, 37b, 37c are closed again and the solar park 2 will sink further until the vertical displacement due to the sinking of the solar park 2 is great enough that the frame 6, more specifically the transverse beams 8 thereof, abut against the top side of the stop bodies 24. From then on, the buoy bodies 22 will also contribute to the upward force of the solar park 2, as a result of which the solar park 2 will sink no further. The lengths of the ventilation pipes 41 and of the drainage pipe 39 are selected such that the upper ends thereof also extend above the water in body of water 1 in the adapted safe position.

Once again with reference to table 1 , the supply of water to the immersion body 31 causes the weight of the solar park 2 to increase by 2%. As a result, the weight of field 3 still forms 93.1% (instead of 95%) of the total weight of solar park 2, and the contribution of immersion body 31 is increased by 1% to 2.9% on account of the water located therein, which is included in the weight of the immersion body 31 in the present model. The 2% increase in the volume of solar park 2, insofar as it extends under water, in the safe position leads only to an increase of about 2% in the upward force, and the downward force is also increased by 2%. It follows from Archimedes’ principle that by supplying an amount of water with a weight equal to 2% (100% - 98%) of X to the immersion body 31 , the solar park 2 can be brought into the safe position. If the mass of field 3 is 9500 kg, then the supply of only 200 kg of water to the immersion body 31 is therefore sufficient to make the solar park 2 sink and thus bring it into the safe position. The immersion body 31, which is significantly less intricate than frame 6 and field 3, makes it possible for water to be supplied to the immersion body, and thus for solar park 2 to be immersed, in a very efficient manner.

As soon as it is subsequently desired to bring the solar park 2 into the operating position again, pump 38 is activated, which pumps water out of the common interior space of immersion body 31 via drainage pipe 39. The ventilation pipes 41 ensure that a vacuum is not produced in immersion body 31. Due to the fact that the weight of the immersion body 31 decreases as the water fill level therein decreases, at a certain point in time the upward force of the solar park 2 will once again be great enough to make it rise to the operating position, in which solar panels 5 extend completely above the water in body of water 1.

In order to prevent undesired sinking of the frame 6 or of the immersion body 31 due to leaks, it is possible to provide inflatable elements such as bags or pipes in interior spaces of the frame and/or the immersion body 31 , said inflatable elements, when being inflated, driving water out of the relevant interior space for example via the relevant leakage hole. In the case of the immersion body 31, such inflatable elements could also serve to drive water out of the immersion body 31 in order to make the system move from the safe position to the operating position. Figures 10a to 15 relate to a second embodiment of a system according to the invention with a floating solar park 102. Insofar as this second embodiment corresponds to the first embodiment described above, use is made of the same reference numerals below and/or in the figures.

The main difference between solar park 2 and solar park 102 is that the immersion body 131 of the floating solar park 102 is not situated under the frame 106, but is actually provided on the top side of the frame 106. The main shape of the immersion body 131 is similar to that of immersion body 31. The pipe bodies of the immersion body 131 extend between the solar panels 5. The diameters of these pipes are selected to be slightly larger than the height of the solar panels 5, as a result of which the pipe parts of the immersion body 131 still extend just above, for example 10 cm above, the top side of the solar panels 5.

Table 2 below applies to solar park 102.

In table 2, V is the total volume of the solar park 102 and X is the total mass of the solar park 102 in the operating position. There is no direct relationship between the values of V and X in table 1 and table 2.

The modified construction of solar park 102 described above has the effect that the immersion body 131 , in the operating position thereof, does not contribute to the upward force of the solar park 102. After all, the immersion body 131 is located completely above the water of the body of water 1 in this operating position. This means that, in principle, the upward force induced by the frame 106 has to be greater than that of frame 6 in order to compensate for the loss of upward force due to the absence of immersion body 31 as in solar park 2. This may for example be effected by selecting the diameters of the pipes from which the pipe systems 110 are constructed to be slightly larger. To this end, it may be necessary for the longitudinal beams 107 and transverse beams 108 of frame 106 to also be dimensioned differently, as will be understood by a person skilled in the art.

A further effect is that the filling of the immersion body 131 with water from body of water 1 , in order to make the solar park 102 sink to a safe position, can no longer take place in a simple manner by opening a ball valve, such as ball valves 37a, 37b, 37c, which extends in the body of water 1. Instead, the activity of a pump which pumps water from body of water 1 into the interior of immersion body 131 will, at least initially, be required. As soon as the underside of immersion body 131 extends in the water of body of water 1, it is, however, of course additionally or even subsequently possible for the immersion body 131 to also fill with water from body of water 1 via an open valve on the underside of the water body 131.

A further effect of the changed design of solar park 102 is that, in principle, the solar park 102 cannot sink any further than to the level where the top sides of the pipe parts of the immersion body 131 just touch the surface of the water in body of water 1. In this sense, the use of buoy bodies as buoy bodies 22 is redundant. Nevertheless, solar park 102 comprises, at the periphery thereof, a number of buoy bodies 122, the embodiment of which is similar to that of buoy bodies 22, in order to prevent excessive tilting of the solar park 102 during the filling of immersion body 131.

In relative terms, in the case of solar park 102, a greater amount of water will need to be introduced into the immersion body 131 in order to bring the solar park 102 into the safe position than the amount of water that has to be introduced for this purpose into immersion body 31 of solar park 2. Following the same logic as has already been described for solar park 2, this means that in the example, where the mass of the field 103 is 9500 kg, it is necessary to supply 990 kg of water to immersion body 131 in order to bring the solar park 102 into the safe position.

The invention has been explained in more detail above by means of the description of two embodiments, but numerous variants of these embodiments are also conceivable within the context of the invention. For instance, it is for example possible for a solar park to be embodied with two or more individual immersion bodies, the interior spaces of which are not in mutual communication with one another, instead of with a single immersion body. In such an embodiment, each immersion body would of course have to have its own provisions to allow water to enter the respective interior spaces of the immersion bodies, and to discharge that water from these interior spaces again.

A solar park according to a system according to the invention may also be provided so as to slowly rotate the entire solar park such that the solar panels thereof remain optimally directed toward the sun over the course of a day.

In a further embodiment, the immersion body used could also be manufactured from flexible material such as a plastics film, which, if filled completely with water, for example assumes the shape of a pipe.

In a further application, the interior space of immersion body 3 or 103 is already filled with water to some extent in the operating position. In tables 1 and 2, the mass of that water would then have to be counted in the mass of the relevant immersion body in the operating position. If the mass of the solar field 2 or 102 is temporarily increased, for example due to the fact that personnel and tools are on it in order to carry out maintenance, then this increase may be temporarily compensated by pumping water out of the relevant immersion body 3, 103. In an alternative embodiment, immersion body 131 may be provided higher above the frame 106, or that immersion body 131 is replaced by two smaller, for example likewise pipe-shaped, immersion bodies which extend parallel to one another between two adjacent solar panels 5. The center axes of these two smaller immersion bodies lie at the same vertical level and may also be situated at a higher level than the center axis of immersion body 131, as shown in figures 14a and 14b, for example. The higher the positioning of the immersion bodies above the frame 106, the lower the solar park 102 can sink in the safe position.

Claims

1. A system for generating electrical energy, comprising a plurality of solar panels and at least one frame on which the solar panels are arranged in rows, wherein the system is displaceable back and forth in the vertical direction between an operating position, in which the system floats on water and the solar panels extend above the water, and a safe position, in which the system is at least partially immersed in the water and the solar panels extend at least largely under water, the system further comprising a displacement device for displacing the system between the operating position and the safe position, the displacement device comprising at least one immersion body with an interior space, which at least one immersion body is connected to the at least one frame for joint displacement in the vertical direction, the immersion device further comprising a supply device for supplying water to the interior space of the at least one immersion body, and also a discharge device for discharging water from the interior space of the at least one immersion body in order to thus increase the floating ability of the system.

2. The system as claimed in claim 1 , wherein the system, excluding any components of the system that cannot be immersed together with the at least one frame from the operating position, has a collective weight and a collective volume, and, in the operating position, the volume of the frame, at least insofar as it extends under water, is at least 80 percent of the collective volume.

3. The system as claimed in claim 1 or 2, wherein the at least one immersion body comprises an immersion body which comprises an elongate first immersion body part and at least one, preferably more than one, elongate second immersion body part/immersion body parts which branches/branch off from the first immersion body part.

4. The system as claimed in claim 3, wherein the at least one second immersion body part branches off at right angles from the first immersion body part.

5. The system as claimed in one of the preceding claims, wherein the at least one immersion body comprises multiple rows of elongate immersion body parts which extend parallel to each other and to the rows of solar panels, wherein the number of rows of immersion body parts is smaller than the number of rows of the solar panels.

6. The system as claimed in claim 5, wherein the number of rows of immersion body parts is smaller than half the number of rows of the solar panels.

7. The system as claimed in one of the preceding claims, wherein the at least one immersion body comprises a number of elongate immersion body parts which together determine at least 90% of the total volume of the at least one immersion body, and of which the sum of the lengths of the individual immersion body parts is smaller than the sum of the lengths of the rows of solar panels.

8. The system as claimed in claim 7, wherein the sum of the lengths of the individual immersion body parts is smaller than half the sum of the lengths of the rows of solar panels.

9. The system as claimed in one of the preceding claims, wherein the at least one immersion body comprises multiple sets of associated elongate immersion body parts, which immersion body parts belonging to a set extend parallel to each other and to the rows of solar panels within the width of a row of solar panels, wherein the number of sets of immersion body parts is smaller than the number of rows of solar panels.

10. The system as claimed in one of the preceding claims, wherein the at least one immersion body is substantially pipe-shaped, at least in the safe position.

11. The system as claimed in claim 10, wherein the pipe shape has a cross section whose surface area is between 700 cm² and 5000 cm², preferably between 1250 cm² and 2800 cm².

12. The system as claimed in one of the preceding claims, wherein the at least one immersion body has a dimensionally stable wall which surrounds the interior space.

13. The system as claimed in one of claims 1 to 11 , wherein the at least one immersion body has a flexible wall which surrounds the associated interior space.

14. The system as claimed in one of the preceding claims, wherein the at least one frame comprises pipes.

15. The system as claimed in claim 14, wherein the pipes are configured to make it impossible for water to enter the respective spaces of the pipes.

16. The system as claimed in claim 14 or 15, wherein the pipes have a cross section whose internal surface area is between 20 cm² and 700 cm².

17. The system as claimed in claim 14, 15 or 16, wherein the pipes are made of fiber-reinforced material.

18. The system as claimed in one of the preceding claims, comprising a limiting device for limiting the extent to which the system may sink in the safe position.

19. The system as claimed in one of the preceding claims, wherein the limiting device comprises buoy bodies and tension elements connected to the buoy bodies, which tension elements, in the safe position, act between the at least one frame and the buoy bodies and are configured to prevent the immersion bodies, together with the at least one frame and the solar panels, from being immersed further in the safe position of the system when the system has sunk over a determined immersion length.

20. The system as claimed in claim 19, wherein the number of buoy bodies is smaller than the number of solar panels.

21. The system as claimed in claim 20, wherein the number of buoy bodies is smaller than half the number of solar panels.

22. The system as claimed in one of the preceding claims, wherein the supply device comprises at least one water pump for pumping water into the interior space of the at least one immersion body, and/or comprises at least one air pump for pumping air out of the interior space.

23. The system as claimed in one of the preceding claims, wherein the discharge device comprises at least one water pump for pumping water out of the interior space of the at least one immersion body, and/or comprises at least one air pump for pumping air into the interior space.

24. The system as claimed in one of the preceding claims, wherein the weight of the solar panels is equal to at least 50%, preferably at least 80%, of the collective weight.

25. The system as claimed in one of the preceding claims, wherein, at least in the operating position, the at least one immersion body extends at least partially, preferably largely, further preferably completely, under water.

26. The system as claimed in claim 25, wherein the volume of the at least one frame is equal to at least 80%, preferably at least 90%, of the collective volume of the system.

27. The system as claimed in claim 25 or 26, wherein, in the operating position, the volume of the at least one immersion body is at most 20%, preferably at most 10%, of the collective volume of the system.

28. The system as claimed in claim 25, 26 or 27, wherein the supply device comprises at least one shut-off valve which, in an open position, allows water to pass from outside an immersion body to the interior space of the at least one immersion body and, in a closed position, blocks such a passage of water.

29. The system as claimed in one of claims 25 to 28, comprising at least one ventilation line which is connected at one end to the interior space of the at least one immersion body and, in the safe position, opens out at an opposite end above water.

30. The system as claimed in one of claims 25 to 29, wherein, in the operating position, up to at least 5% of the interior space of the at least one immersion body is filled with water.

31. The system as claimed in one of claims 1 to 27, wherein, at least in the operating position, the at least one immersion body or at least the interior space thereof extends completely above water.

32. The system as claimed in claim 31, wherein the volume of the at least one frame is equal to at least 80%, preferably at least 90%, of the collective volume of the system.

33. The system as claimed in claim 31 or 32, wherein, at least in the safe position, top sides of the at least one immersion body are situated at the same level as or above the top sides of the solar panels.

34. The system as claimed in one of claims 31 to 33, wherein the at least one immersion body extends between adjacent rows of the solar panels.