SE1100185A1 - Device and method for converting wave power to electrical energy - Google Patents

Abstract

A method and apparatus for converting energy in water waves to electrical energy by providing a closed container (2) arranged to surface on a water surface with its longitudinal direction substantially in a propagation direction for waves occurring on the water surface, the container (2) being provided with space (Sa, 6a) which can communicate with each other and said space located one at each end of the container (2), and where the container (2) is filled with a liquid (3) to a predetermined sub-volume, wherein when one of said spaces (Sa , 6a) at one end of the container (2) due to detonation moves at a predetermined higher level than the other space (Sa, 6a) at the other end of the container (2) flows liquid (3) which settles in the higher the locating space (Sa, 6a) over to the lower located space (Sa, 6a) and thereby passes a turbine (7) present in a led direction which due to the inclination of the container (2) joins the boathouses (Sa, 6a) whereby the turbine (7 ) is rotated and electrical energy is generated in a generator (12) connected to said turbine (7) and where said flow is arranged to take place substantially in a vertical plane through the longitudinal direction of the container. (Fig. 3)

Description

managed the seawater, which must be remedied by means of filtration and measures in the form of recurring inspections.

A further principle for utilizing wave power is known from the document EP 0 483 357 A1, in which a mass is arranged to rotate about a horizontal axis of rotation at a distance from the mass, when it moves up or down in a frame which stands on the seabed. Thereby, the repeated movements of the waves are converted into rotary motion which can be converted into electrical energy.

U.S. Pat. No. 43,92061 discloses a device which utilizes a liquid enclosed in a space where the liquid is moved back and forth in a rocking motion in step with a wave motion. The liquid drives means for embracing energy in the wave motion. The device in this case consists of a large, e.g. anchored in a sea area, vessels arranged to fl surface on the surface and to rockingly follow the rhythm of water waves at the site. The vessel has chambers that contain a liquid that moves along the vessel at the same frequency as the rocking motion of the vessel. Furthermore, the device comprises means, e.g. turbines, which are located along the path of the liquid for fl surfaces in the vessel, to recover energy from the wave motion. Said energy is extracted by horizontal transfer of water masses between said chambers.

The device according to FR 2499161 A2 shows a container which contains rooms in plan your planes, where a certain amount of water is enclosed in the container. The idea of this known device seems to be to provide high positional energy of the water which in your steps is transported upwards to higher located rooms by wave movements by means of a number of flaps which are opened and closed in step with the wave movements, after which the water flows downwards through a turbine. positional energy of the water to kinetic energy of the turbine. This step-by-step increase in the water takes place in rooms located on the same side of the turbine. A device of this kind becomes a sluggish and complex device. The known device should require a high height of the waves on the surface so that the lower part of the container does not counteract the rocking unless there is a wave movement at the lower part of the container in phase with the waves at the surface. In addition, the division of the device into several floors leads to a high level of complexity. According to the embodiment, a large number of flaps at different heights will be required. This means a greater risk of malfunction and also great difficulty in carrying out service.

DESCRIPTION OF THE INVENTION The present invention relates to a method and an apparatus for converting energy in water waves into electrical energy. The invention is based on the use of a closed container which is arranged to surface on a water surface, usually in a sea area, in order to recover energy in waves at the water surface. The container is anchored at a certain position and thus rocks back and forth in the vertical direction with the same frequency as the waves at the water surface. The rocking motion is effected by the lifting of the waves by one or the other end of the container.

The container is further filled with a liquid to a predetermined subset of its volume, where the entrapped liquid flows back and forth between its two ends in step with the rocking of the container caused by the wave motion at the water surface. In this case, the container is positioned so that it fl surfaces on the water surface and rocks in the direction of propagation of the waves. The container fl surfaces on the water due to the proportion of air that is inside it.

At each end of the container is a space, arranged for receiving and dispensing the enclosed liquid, respectively, depending on the rocking movement of the container. Said room is thus used as a liquid depot.

When one of said compartments at one end of the container due to the wave motion is at a predetermined higher level than the other compartment at the other end of the container, liquid which settles in the higher compartment flows over to the lower compartment and passes wherein a turbine is present in a channel which is arranged to join the two chambers, the turbine being rotated and electrical energy being generated in a generator connected to said turbine.

The flow of the liquid inside the closed container is arranged to take place substantially in a vertical plane through the longitudinal direction of the container, the longitudinal direction being perceived as the direction between the two rooms located at each end of the container.

The container in the device can be designed geometrically in many different ways. Characteristic of the device is that it is provided with a centrally arranged water reservoir which is located above a turbine. Under the turbine there is a drainage for receiving the liquid that passes through the turbine. The principle is such that the liquid fl breathes cyclically with the wave motion: 0 from the drain to one room, 0 then to the reservoir, ø down through the turbine to the drain, 0 from there to the other room, 0 again to the water reservoir, 0 passes through the turbine again and back to the drainage.

In reality, it is not a given that all entrapped fluid during a period of wave motion fl dies exactly according to the schedule, since external circumstances can affect fl fate, such as wind, irregular wave motion, etc.

According to one aspect of the invention, there is provided a method having features according to the method specified in claim 1.

Furthermore, a device for implementing the method is presented in the independent device requirement.

Further embodiments of the invention are presented in the dependent claims.

By means of doors which are opened and closed during the movement of the liquid inside the container, the two compartments are filled, at least in part, alternately by the liquid mass reciprocating in the container.

The ports are arranged to create a channel from one to the other room, at least one turbine being passed by the liquid in the channel, when the liquid flows over from one to the other room. The gates, also called flaps, can be arranged so that they are opened or closed automatically by the force of the flowing water. As a preferred alternative, counterweights can be applied to the ports so that they open, almost by themselves, under the influence of the inclination of the container and the force of gravity. In this way no power is lost in the StfÖmmaHdC VaftCDInaS San.

An advantage of the device and method according to the invention is that it uses very few components and a minimum of moving parts.

Furthermore, the liquid inside the container is arranged to substantially da in a pattern back and forth in a vertical plane through the longitudinal direction of the container. Here, as an example, turbines will be able to be arranged for substantially vertical fates of the liquid flowing through the turbine or turbines. In the closest prior art, according to the specification US 4392061, where horizontal water flows are applied, the liquid passes the turbines horizontally from a water reservoir located horizontally in relation to the turbine. This causes an uneven load on the turbine blades, as the water level drops during energy consumption. By allowing the fluid to pass through a vertical turbine from a vertical reservoir located above the turbine, the power from the fluid is distributed evenly over the turbine blades.

DESCRIPTION OF THE FIGURES Fig. 1 describes a schematic representation of a side view with the device according to the invention in a horizontal rest position.

Fig. 2 describes in a side view the device according to Figure 1, where it is described how the enclosed liquid begins to move when the container sways to the left from the rest position.

Fig. 3 shows in a corresponding side view according to fi figure 2 fl the fate of the enclosed liquid when the container sways over to the left during normal operation.

Fig. 4 shows in a fi gur corresponding to fi gur 3 fl the fate of the enclosed liquid when the container sways to the right during normal operation.

Fig. 5 very generally presents a perspective view where the container according to the invention due to wave motion descends at its left end and is pushed up at its right end.

Fig. 6 shows in a manner corresponding to Figure 6 how the container according to the invention due to wave motion is pushed up at its left end and sinks down at its right end.

DESCRIPTION OF THE EMBODIMENTS In the following, a number of embodiments of the invention are described with reference to the accompanying drawings. The drawings only schematically show the principle of the device and do not claim to show in scale any proportions between different elements thereof.

Figure 1 shows a device 1 according to the invention aspect with a container 2 in the rest position, ie. under a condition where it fl is horizontal. The container 2 is, as mentioned, intended to be placed, for example, at sea, where energy from sea waves can be recovered and converted into electrical energy by means of the present device. For this purpose, the container 2 is closed and intended to partially, ie. to a certain sub-volume, be filled with a liquid 3. In the embodiments described herein, water, preferably fresh water, is used as the liquid with which the container 2 is partially filled. In this case, the reference numeral 3 must also be interpreted as meaning that it can be any liquid despite that it is referred to herein only as water. The partial volume of water 3 with which the container 2 is partially filled can be determined by the external conditions in which the container is used. The subvolume can thus depend on the average wave height that occurs at the site, the wavelength that is considered to be the predominant one and the depth at which the container is to surface in the water, as some examples.

The container is also equipped with an anchor. This anchorage may consist of a rope or chain fixed at one end of the container and attached to the seabed, the container will surface in the direction of movement of the waves from the anchorage 14.

The container 2 is further divided into different sections. Thus, in a variant, the container consists of three tanks connected by means of tubes, the container being divided into a structure of rooms and channels. According to the example, the adjacent tanks consist of a central tank 4 and at each end of the container 2, a first tank 5 and a second tank 6. The central tank 4 houses water reservoirs 4a, turbine 7 and drainage 4b. In the example, a first tube 8 connects the central tank 4 to the first tank 5 and a second tube 9 connects the central tank 4 to the second tank 6. The connection between the central space 4 and the two tanks 5 and 6 can of course as an alternative arranged by means of your first tubes 8 resp. fl your other tubes 9.

By using the tanks 5 and 6, spaces 5a and 6a are formed, one at each end of the container 2. Preferably, but not necessarily, the container 2 is elongate, whereby the ends of the container referred to herein are equated with the ends of the container facing the waves. surrounding the container 2. In a first embodiment of the invention, closed air bulkheads 5b and 6b are arranged below each of the spaces 5a, 6a at the ends of the container.

These air bulkheads 5b, 6b are arranged to balance the container in the water in an advantageous manner.

From the first space 5a at one end of the container, a first channel 8a runs through the first tube 8 to and murmurs in the substantially vertically arranged water reservoir 4a whose lower partition wall, i.e. its bottom 4c, is arranged some distance above the drain 4b. Correspondingly, a second channel 9a runs from the second space 6a in the container, which also opens into the water reservoir 4a. At the bottom of the water reservoir 4a the turbine 7 is arranged in its central part. This turbine 7 is arranged to be rotated when water which settles in the water reservoir 4a flows down through the turbine 7 towards the drainage 4b in the central part of the container 2.

A third channel 8b joins the drain 4b with the first space Sa. Correspondingly, a fourth channel 9b connects the drainage 4b to the second space 6a.

It also appears from the att guren that water 3 fills up a certain sub-volume of the container 2. Flaps 11a, 11b can close or open the mentioned channels 8a, 8b, 9a, 9b in the manner described in the following. Here it can be approached that the flaps 11a, 1lb form a kind of gates which are articulated along one of its edges and thus can rotate an angle around this joint. Said joints are marked as filled small filled circles in the ur gurema. In order to arrange a stop and sealing, other edges of the flaps can be arranged so that the flap of its own weight or of water pressure abuts against a strip, seam, elevation or equivalent in a wall connecting to the flap. These details have not been shown in the ur gurema.

The turbine 7 is connected to a generator 12 by means of a shaft 13, the generator 12 being arranged on the inside or outside of the container 2. If the container is designed so that the space constituting the water reservoir 4a has a raised section, the generator 12 can be mounted internally. When the turbine 7 is rotated, electrical energy will be induced in the generator, from which the electrical energy can be distributed in a manner not described here.

With the support of steps 2 to 4, the function of the device according to the invention when it is in operation is described. The first of these, Figure 2, illustrates the beginning of the movement pattern of the enclosed water 3, when it is set in motion by the lifting force of a wave, which in this case according to the figure moves to the right and with its wave crest lifts the right end of the container 2 .

Thus, when the container has rocked to the left, by which is meant that its left end has sunk to a lower level than its right end, the flap 11a will be opened due to the inclination of the container in combination with the gravity and / or of the water flowing from the right end of the channel 8b to the left in the fi guren. The water 3 thus comes p. G.a. the inclination of the container 2 to flow from the drain 4b along the channel 8b through the opened flap 11a, whereby the space Sa is filled with water until the container 2 walls to the right when a new wave crest reaches the left end of the container.

When the container 2 rocks over to the right, according to fi gur 4, p.g.a. that a new wave top from the next wave affects the left end of the container with an upward force, the flap 11a is closed due to the changed inclination of the container and the left space Sa begins to be emptied. The water from the room Sa flows along the channel 8a and falls into the water reservoir 4a. Also in this case this flow takes place only when the inclination of the container exceeds said predetermined angle. The water fills the water reservoir 4a again, so that the water in the water reservoir 4a can continuously flow downwards and pass the turbine 7, so that it is constantly rotated. The water which has fallen through the turbine 7, at the container slope to the right, first falls into the drain 4b and flows further to the right in the channel 9b. In the channel 9b, flap 1 lb is opened due to the inclination of the container, so that the water from the channel 9b begins to fill the right space, i.e. the second room 6a. The fate of the water through the turbine 7 has here been achieved through an open second path which in this position, when the container sways over to the right, consists of the channel 8a, the water reservoir 4a, the drainage hole 4b and the channel 9b. This second path 8a, 4a, 4b, 9b thus constitutes a path with which the space Sa and the space 6a communicate directly when the container tilts over in one direction, in this example to the right in the clock 4.

When the container 2 again rocks over to the left, according to 2 gur 2 as described above, p.g.a. that a wave crest affects the right end of the container with an upward force, the flap 1 lb is closed due to the changed inclination of the container and the second space 6a begins to be emptied. The water from the room 6a then flows along the channel 9a to the left and falls into the water reservoir 4a, as shown in Figure 3, where the second room 6a has already been emptied into the channel 9a and the water reservoir 4a. Of course, this flow occurs only when the inclination of the container exceeds a certain predetermined angle, which depends on the height of the water reservoir 4a.

A typical angle of inclination is in the range S ° - 20 °. The water collected in the water reservoir 4a can flow further downwards and pass the turbine 7, so that it is rotated. Hereby the said transfer from energy in the water waves to electrical energy is effected, since the turbine 7 drives the generator 12. The water which has fallen through the turbine 7 flows further to the left in the channel 8b, as shown above. The fate of the water through the turbine 7 has been achieved through an open first path which in this position, when the container sways over to the left, consists of the channel 9a, the water reservoir 4a, the drainage hole 4b and the channel 8b. This first fate path 9a, 4a, 4b, 8b thus forms a path with which the space 6a and the space Sa communicate directly when the container tilts over in one direction, in this example to the left.

It should be mentioned here that the container 2 may contain fl your bulkheads, which are produced by means of walls in the longitudinal direction of the container 2. The flow in each of the bulkheads will thereby correspond to the flow pattern described above. In the case of fl your parallel shots, one turbine can be arranged per shot. There is also nothing to prevent a single shot or when using your shots that each of the shots is equipped with more than one turbine 7, ie. when using the term turbine, it should be understood that this can also refer to a turbine group.

Figures 5 and 6 illustrate with very schematic figures in a simplified perspective how the device according to the invention appears in water under the influence of water waves. In Figure 5, a scale has lifted the right end of the container 2, while in Figure 6, a scale has lifted the left end of the container.

Of course, it is possible to design the container and its internal structure in different ways with different geometries. Characteristic of the device in different embodiments is, however, that it is provided with a central room, which from higher to lower level includes liquid reservoir, turbine and drainage with function as described above. Furthermore, the central space communicates with a liquid depot at each end of the container. The wet depots correspond in the given example of the first room Sa and the second room 6a. The principle is further that the liquid depot at one end of the container communicates directly via an open flow path through a turbine with the liquid depot at the other end of the container. The path of the open path of fate depends on which of the two liquid depots is at a higher level, for example as shown in the described exemplary embodiment.

Dimensions for containers, tubes, rooms and ducts resp. turbine flow areas, should be adapted to the characteristics of the waves at the anchorage site in question. Sizing wave data can be, for example, the length, average height, and period of the waves.

The dimensions of the container in the device may vary depending on the wave conditions at the place where it is placed. For the embodiment according to Fig. 1, as an example, the ratio between length, width and height can be 12m, 10m, resp. 3m.

Example: Theoretical calculations show that a device according to one of the proposed embodiments can give about 1 kW per meter width of the container. This effect can be achieved already at a wave height of one meter. A total output power of 10 kW is obtained from a tank having a width of 10 m and a length of 12 m at a wave period of 4 seconds on the high seas and where the entire volume of water collected at one end of the tank flows through the turbine (turbine group) for 2 seconds. With a fully open channel, a depot at one end of the container would be emptied in about half a second, but since the arranged turbine provides a flow resistance, it can be arranged that the depot is emptied in said 2 seconds, which makes the depot empty or almost empty, when the container rocks over in the other direction. In this example, the calculations have been performed for a container that encloses about 15 m3 of liquid. Further conditions are an average fall height of 0.78 m.

A wave with a wavelength of about 24 m and which is one meter high calculated from wave valley to wave peak gives a total power of 10 kW.

De fi nition The longitudinal direction of the container 2 refers to the direction between the rooms 5a and 6a located at the ends of the container.

Claims (10)

A method of converting energy in water waves to electrical energy, comprising the steps of: - providing a closed container (2) arranged to surface on a water surface with its longitudinal direction substantially in a propagation direction for waves occurring on the water surface, - arranging a first (Sa) and a second (6a) communicable space located at each end of the container (2), - filling the container (2) with a liquid (3) to a predetermined subvolume, characterized that when one of said compartments (Sa, 6a) at one end of the container (2) due to wave motion is at a predetermined higher level than the other compartment (Sa, 6a) at the other end of the container (2 ) liquid (3) which settles in the higher space (Sa, 6a) flows via an open fate path (9a, 4a, 4b, 8b, respectively 8a, 4a, 4b, 9b) over to the lower space (Sa , 6a) and thereby passes a turbine (7) substantially in the open fate path which is arranged to unite the two said chambers (Sa, 6a) wherein the turbine (7) is rotated and electrical energy is generated in a generator (12) connected to said turbine (7), that both said first chambers (Sa) resp. said second space (6a) during a period of the wave motion alternately constitutes the higher, resp. the lower space, and that said flow is arranged to take place substantially in a vertical plane through the longitudinal direction of the container. Method according to claim 1, comprising the step: - said spaces (Sa, 6a) are arranged to communicate with each other by means of flaps (11a, 11b) which alternately open: a) a first första joint (8a, 4a, 4b, 9b) from first (Sa) of said space to the second (6a) of said space and b) a second fl fate path (9a, 4a, 4b, 8b) from said second space (6a) to said first space (Sa), the des fate paths being laid out so that said turbine (7) is permanent in both the first (8a, 4a, 4b, 9b) and the second duct (9a, 4a, 4b, 8b). Device for converting energy in water waves to electrical energy, wherein the device comprises a closed container (2) arranged to surface on a water surface with its longitudinal direction substantially in a propagation direction for waves occurring on the water surface, characterized in that the container (2) is provided with a central space (4), which from higher to lower level comprises a liquid reservoir (4a), a turbine (7) and a drainage (4b), said central space (4) communicating with a liquid depot (Sa, 6a) in each the end of the container 10 15 20 25 30 12 (2), where the liquid depot (Sa, 6a) at one end of the container (2) communicates directly via an open led path (9a, 4a, 4b, 8b, respectively 8a, 4a, 4b, 9b), wherein the turbine (7) is mounted, with the liquid depot (Sa, 6a) at the other end of the container (2) and where a liquid (3) enclosed in the container generates the electrical energy when a wave motion on the water surface brings the liquid (3) flowing from a higher located liquid depot (Sa, 6a) to a lower located liquid depot ( Sa, 6a) along the fate path and thereby rotates the turbine (7) which is connected to a generator (12). Device according to claim 3, wherein the container (2) is arranged to be partially filled with a liquid (3), preferably water and in particular fresh water. Device according to claim 4, wherein one of said liquid depots consists of a first chamber (Sa) and the second liquid depot of a second chamber (6a) and wherein said first and second chambers are connected to the central space via tubes (8, 9 ). Device according to claim 5, wherein said open path comprises: - a first channel (8a) in the first tube (8), the water reservoir (4a), the drain (4b) and a second channel (9b) in the second tube (9 ), when the container (2) is inclined at a certain angle in one direction, - a first channel (9a) in the second tube (9), the water reservoir (4a), the drain (4b) and a second channel (8b) in the first tube (8), when the container (2) is inclined at a certain angle in the other direction. Device according to claim 6, wherein the inclination of the container determines which of said fl fate joints is open by flaps (11a, 1lb) which open or close the fate joints. Device according to claim 7, wherein the flaps (11a, 1lb) consist of doors which are rotatably arranged in joints arranged horizontally and transversely to the longitudinal direction of the container, around which joints the doors can rotate and be opened or closed by their weight under the influence of the container ( 2) inclination in cooperation with the gravitational force and / or with the aid of the force in the liquid flowing past the flap (11a, 11b) (3). 10 13 Device according to any one of claims 3 - 8, wherein said turbine (7) is located at the bottom 10. (4c) of the water reservoir (4a) which is filled with water when the container (2) repeatedly rocks up and down with a minimum angle of inclination within range 5 ° - 10 °. Device according to any one of claims 3-8, wherein: the first space (Sa) is included in a tank (5) which also houses a first air shot (5b) and the second space (6a) is included in a tank (6 ) which also houses a second air shot (6b).