GB2538505A

GB2538505A - Wave valves

Info

Publication number: GB2538505A
Application number: GB1508508.7A
Authority: GB
Inventors: Frank Murphy Stuart
Original assignee: Individual
Current assignee: Individual
Priority date: 2015-05-18
Filing date: 2015-05-18
Publication date: 2016-11-23
Anticipated expiration: 2035-05-18
Also published as: WO2016185207A1; GB201508508D0; GB2538505B

Abstract

A wave energy storage system comprises a wave valve, which allows relatively free inwards movement of wave crests into a lagoon (reservoir), but prevents flow in the opposite direction out of the lagoon. The system uses a pivoted wave retainer 11, which is curved in a hook shape to assist sea waves in overtopping the retainer, but to contain waves within the lagoon. The retainer 11 may be mounted on a movable base 12 to adjust for tide height, possibly using buoyant members 13A, 13B.

Description

Wave Valves

Field of the Invention

The present invention relates to wave valves, to barrage systems that incorporate wave valves, and to related methods.

Background to the Invention

Tidal energy systems offer the potential to generate electricity while avoiding disadvantages associated with using fossil fuels in generation. In order to increase the efficiency of tidal energy systems it is desirable to maximise the amount of water that flows through the turbines, so for systems that employ tidal storage a location that that has a large tidal range is preferred. Such locations are often exposed to the open sea, meaning that the tidal energy system requires protection to be installed for the turbines and associated tidal storage structures.

Example embodiments aim to address issues associated with the prior art, whether identified herein or otherwise.

Summary of the Invention

In one example embodiment there is provided a wave valve arranged to retain wave crests on an inward side thereof by relatively free inward movement of a retainer under influence of inwardly incident waves and relatively restricted contrary movement thereof.

In one example embodiment there is provided a wave valve comprising a retainer that is in use biased toward a rest position.

In one example embodiment there is provided a wave valve comprising a retainer that is in use biased by buoyancy.

In one example embodiment there is provided a wave valve comprising a retainer that is arranged in use to move against its bias in response to inwardly incident waves, thereby to allow the crests of inwardly incident waves to pass over the retainer and be retained on the inward side thereof In one example embodiment there is provided a wave valve comprising a retainer arranged in use with relatively free inward movement over a working range of movement so that in use the retainer moves downward through the working range under influence inwardly incident waves and upward within the working range to retain wave crests on the inward side thereof in response to incident waves in the contrary direction.

In one example embodiment there is provided a wave valve arranged such that contrary movement of the retainer is relatively restricted by a stop which the retainer does not pass.

In one example embodiment there is provided a wave valve comprising a stop arranged such that contrary movement of the retainer is restricted by the stop to prevent outward movement of the retainer beyond the stop.

In one example embodiment there is provided a wave valve comprising a retainer mounted to pivot about an axis at a lower end thereof such that inward movement of the retainer under influence of inwardly incident waves is accompanied by downward movement.

In one example embodiment there is provided a wave valve comprising a retainer mounted to pivot between upright and lain down positions. Suitably, the upright position is relatively vertical, and the lain down position is relatively horizontal, extending in the inward direction from the pivot.

In one example embodiment there is provided a wave valve in which the retainer comprises the uppermost portion of the wave valve, for retention of waves on the inward side thereof.

In one example embodiment there is provided a wave valve comprising a retainer that presents a generally convex surface to inwardly incident waves.

In one example embodiment there is provided a wave valve comprising a retainer that presents a generally concave surface on its inward facing side.

In one example embodiment there is provided a wave valve comprising a retainer that in cross section comprises a generally hooked profile, concave on its inward facing side.

In one example embodiment there is provided a wave valve comprising a base that carries the retainer and which is configured to support the retainer at a retention position.

In one example embodiment there is provided a wave valve comprising a base, and the base comprising a barrier below the retainer, and operable in use to move up or down to a retention position according to the depth of inwardly incident waves.

In one example embodiment there is provided a wave valve comprising a buoyant base, for example a base of variable buoyancy.

In one example embodiment there is provided a barrage system comprising a wave valve as set out in any one or more of the example embodiments above.

In one example embodiment there is provided a barrage system comprising one or more underwater wave drivers arranged to increase the height of inwardly incident waves. In one example embodiment there is provided a barrage system comprising one or more underwater wave drivers arranged to increase the height of inwardly incident waves by projecting upwards from the sea floor. In one example embodiment there is provided a barrage system comprising a plurality of underwater wave drivers arranged to increase the height of inwardly incident waves by providing an effective reduction in depth that increases toward the barrage.

In one example embodiment the wave drivers comprise a plurality of ridges projecting from the sea floor, with valleys there-between. In one example embodiment the wave drivers comprise a plurality of ridges projecting from the sea floor, with successively shallower valleys there-between toward the barrage. In one example embodiment the wave drivers comprise a plurality of ridges projecting from the sea floor, with successively narrower valleys there-between toward the barrage.

In one example embodiment there is provided a barrage system comprising a wave funnelling region that presents a relatively wide reception portion to receive inwardly incident waves, and relatively narrow funnelling portion at the wave valve.

In one example embodiment there is provided a method of retaining wave crests on an inward side of a wave valve, the method comprising: allowing relatively free inward movement of a retainer of the wave valve under influence of inwardly incident waves; and relatively restricting contrary movement of the retainer.

In one example embodiment there is provided a wave valve comprising a buoyant retainer.

In one example embodiment there is provided wave valve comprising a retainer biased toward an upward position and arranged to move against the bias in response to waves incident thereon in a first direction, thereby to allow waves incident thereon in the first direction to pass in the first direction.

In one example embodiment there is provided a wave valve comprising a retainer arranged to move downwardly in response to waves incident thereon in a first direction and to move upwardly in response to waves incident thereon in a second direction, thereby to allow waves incident thereon in the first direction to pass over and to obstruct waves incident thereon in the second direction.

According to the present invention there is provided an apparatus and method as set forth in the appended claims. Other features of the invention will be apparent from the dependent claims, and the description which follows.

Brief Introduction to the Drawings

For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings in which: FIG. 1 shows a schematic plan view of a barrage system according to an example embodiment of the present invention; FIG. 2A shows a schematic front view of a wave valve according to an example embodiment of the present invention; FIG. 2B shows a schematic front view of a plurality of wave valves according to an example embodiment of the present invention arranged between support towers; FIG. 2C shows a schematic plan view of a plurality of wave valves according to an example embodiment of the present invention adjacent a support tower; FIG. 3A to FIG. 3F show schematic side views of a wave valve according to an example embodiment respectively at rest when the tide is out; as the tide starts to come in; at a shallow tide; at a medium tide; momentarily before high tide; and at high tide; FIG. 4A shows a schematic side view of wave drivers arranged with a wave valve in a barrage system according to an example embodiment, at a relatively shallow tide; FIG. 4B shows a schematic side view of wave drivers in the barrage system of FIG. 4A, at a relatively high tide; FIG. 5A shows a schematic sectional view of a wave funnelling region in a barrage system according to an example embodiment, at a relatively shallow tide; and FIG. 5B shows a schematic sectional view of a wave funnelling region in the barrage system of FIG. 5A, at a relatively high tide.

Description of Example Embodiments

FIG. 1 shows a schematic plan view of a barrage system according to an example embodiment of the present invention. The barrage system is for generating electrical energy from the tidal movement of sea water. Water is allowed to flow into storage basins B, which are also referred to as lagoons, as the tide rises, and allowed to flow from the barrage system once the tide has gone out. Movement of water into and out of some of the storage basins is used to drive turbines that are coupled to electrical generators. The barrage system of FIG. 1 incorporates wave walls 1 that comprise wave valves 10.

The wave valves 10 are arranged to retain wave crests on an inward side thereof by relatively free inward movement of a retainer under influence of inwardly incident waves, and relatively restricted contrary movement thereof. In this way the wave crests can be used to increase the amount of water retained in the barrage system compared to that which would be possible in the absence of waves and wave valves, thereby increasing the amount of stored energy potential available for conversion to electrical energy. The wave valves 10 also serve as the seaward portion of the barrage system, and as such are arranged to protect the turbines and other components of the barrage system from damage by storm swells etc. The wave valves 10 and associated support towers 20 that make up the wave walls 1 are shown in more detail in FIG. 2A, FIG. 2B and FIG. 2C. The wave walls 1 are provided by a plurality of wave valves 10 arranged next to one another, with support towers 20 reinforcing the wave wall 1. Providing the wave valves 10 as individually operating sections of the overall wave wall 1 enables the wave valves 10 to operate efficiently according to the local wave height in that region of the wave wall 1. For example in FIG. it can be seen that the local height of the wave valves 10 is different at different positions across the wave wall 1, as the instantaneous position of the retainers of the wave valves 10 will depend on the size and incident direction of waves incident thereon. FIG. 3A to FIG. 3F explain the operation of the wave valve 1 and its retainer 11, base 12 and buoyancy unit 13.

FIG. 3A shows a schematic side view of a wave valve 10 at rest when the tide is out. The retainer 11 is carried by the base 12, being mounted thereon at a pivot. The retainer 11 is biased toward a rest position as shown in FIG. 3A, in which it is lain down relatively horizontal, and extends in the inward direction from the pivot. The base 12 is configured to support the retainer 11 at a retention position and can in use to move up or down to the retention position according to the depth of inwardly incident waves. In FIG.3A the base 12 is moved fully down, into a recess in the sea bed.

As the tide starts to come in the retainer 11 is biased by buoyancy toward an upright position, a process which is starting in FIG. 3B. However, at this point there is insufficient depth for the wave valve 10 to operate.

FIG. 3C shows the wave valve 10 at a shallow tide, with the retainer 11 floating and allowing an inwardly incident wave to pass over itself. The base 12 is supporting the retainer 11 at the retention position by floatation provided by the buoyancy unit 13, which comprises inner and outward components 13A, 13B.

All the while as the tide rises through the positions shown in FIG. 3D and FIG. 3E the retainer 11 moves against its bias in response to inwardly incident waves, thereby allowing the crests of inwardly incident waves to pass over the retainer 11 and be retained on the inward side thereof. The retainer 11 is arranged in use with relatively free inward movement over a working range of movement so that in use the retainer 11 moves downward through the working range under influence inwardly incident waves and upward within the working range to retain wave crests on the inward side thereof in response to incident waves in the contrary direction.

FIG 3F shows the position of the base 12 of the wave valve 10 at high tide, and the 25 retainer 11 substantially vertical. Movement of the retainer outwardly, past this vertical position is restricted by a stop which the retainer does not pass.

To improve retention of the crest of waves by the retainer 11, the retainer 11 presents a generally convex surface to inwardly incident waves and a generally concave surface on its inward facing side.

In order to further enhance the operation of the wave valves 10 it is desirable for the waves incident thereon to be of suitable amplitude, which can be engineered to occur more frequently by use of wave drivers 31-34. FIG. 4A shows a schematic side view of wave drivers 31-34 arranged with a wave valve 10 in a barrage system according to an example embodiment, at a relatively shallow tide. FIG. 4B shows the wave drivers 31-34 operating at a relatively higher tide than shown in FIG. 4A.

The wave drivers 31-34 increase the height of inwardly incident waves by providing an effective reduction in depth that increases toward the barrage. Ridge of the wave drivers 3134 projects from the sea floor, with valleys there-between. The valleys successively narrow toward the wave wall 10 thereby forcing moving waves to increase in effective height.

A further enhancement is provided by the arrangement if FIG. 5A and FIG. 5B, in which a wave funnelling region 40 that presents a relatively wide reception portion to receive inwardly incident waves, and relatively narrow funnelling portion at the approach to the wave valve is shown. From these drawings and the plan view of FIG. 1 the operation of the funnelling region 40 can be ascertained, serving to increase the effective depth of waves as they move through a narrowing channel.

The methods and apparatus described herein may increase efficiency in tidal barrage systems and this enhance the environmental and other benefits associated with generation of electrical energy by capturing energy from tidal sources.

Although a few preferred embodiments have been shown and described, it will be appreciated by those skilled in the art that various changes and modifications might be made without departing from the scope of the invention, as defined in the appended claims.

Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.