WO2003078831A1 - Submerged wave energy transformer - Google Patents

Submerged wave energy transformer Download PDF

Info

Publication number
WO2003078831A1
WO2003078831A1 PCT/GB2003/001031 GB0301031W WO03078831A1 WO 2003078831 A1 WO2003078831 A1 WO 2003078831A1 GB 0301031 W GB0301031 W GB 0301031W WO 03078831 A1 WO03078831 A1 WO 03078831A1
Authority
WO
WIPO (PCT)
Prior art keywords
fluid
pressure
reservoir
valves
reservoirs
Prior art date
Application number
PCT/GB2003/001031
Other languages
French (fr)
Inventor
Alexander George Southcombe
Original Assignee
Capcis Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Capcis Limited filed Critical Capcis Limited
Priority to GB0418921A priority Critical patent/GB2401155A/en
Priority to AU2003212523A priority patent/AU2003212523A1/en
Publication of WO2003078831A1 publication Critical patent/WO2003078831A1/en

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03B—MACHINES OR ENGINES FOR LIQUIDS
    • F03B13/00—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates
    • F03B13/12—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy
    • F03B13/14—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using wave energy
    • F03B13/148—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using wave energy using the static pressure increase due to the wave
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/30—Energy from the sea, e.g. using wave energy or salinity gradient

Definitions

  • the present invention relates to a method and apparatus for capturing the fluid pressure of a fluid, more particularly, for capturing the maximum and/or minimum fluid pressure of a fluid of fluctuating and variable pressure, such as, for example, sea water.
  • My co-pending British Patent Application GB-A-9920714.4 describes a device for harnessing wave energy.
  • This device is designed to float just below the surface of the water and comprises a high-pressure reservoir connected to a low-pressure reservoir via a power generator.
  • the high- pressure reservoir has a line of non-return valves which admit water as a wave crest passes over the apparatus, and the low-pressure reservoir has a line of non-return valves to release water as a wave trough passes over the apparatus.
  • the pressure differential set up between the two reservoirs is used to drive the power generator.
  • a method for capturing the maximum or minimum fluid pressure of a fluid of fluctuating and variable pressure comprising the steps of submerging in the fluid a closed reservoir having a plurality of one-way valves arranged in a two-dimensional array on at least one of its surfaces such that when the pressure of external fluid differs from the pressure of fluid within the reservoir by a predetermined amount the pressure differential serves to open at least one of the valves so that fluid passes into or out of the reservoir via said valve, the pressure of the fluid in the reservoir tending to the maximum or minimum pressure of the external fluid.
  • the one-way valves are arranged to open inwards into the reservoir so that when the external fluid pressure at any point above the valves exceeds the fluid pressure inside the reservoir by said predetermined amount at least one of said valves opens to allow fluid into the reservoir, pressure of the fluid in the chamber tending to the maximum pressure of the external fluid.
  • the one-way valves may be arranged to open outwards of the reservoir so that when the fluid pressure inside the reservoir exceeds the external fluid pressure at any point at least one of said valves opens to allow fluid out of the reservoir, the pressure of the fluid in the chamber tending to the minimum pressure of the external fluid.
  • two such reservoirs are interconnected with a first of such reservoirs having one-way valves arranged to open inwards into the reservoir so that when the external fluid pressure at any point above the valves exceeds the fluid pressure inside the reservoir by said predetermined amount at least one of said valves opens to allow fluid into the reservoir, pressure of the fluid in the first reservoir tending to the maximum pressure of the external fluid and a second of such reservoirs having one-way valves are arranged to open outwards of the reservoir so that when the fluid pressure inside the reservoir exceeds the external fluid pressure at any point at least one of said valves opens to allow fluid out of the reservoir, the pressure of the fluid in the second reservoir tending to the minimum pressure of the external fluid, the fluid in the first reservoir flowing into the second reservoir to eliminate the pressure differential between the reservoirs.
  • the pressure in the first reservoir thus tends to the highest pressure in the variable pressure region and the pressure in the second reservoir tends to the lowest pressure in the variable pressure region.
  • the fluid entering the first reservoir under, for example, a wave peak may be evacuated from the second reservoir half a wavelength later.
  • the kinetic energy of the flow of fluid between the reservoirs may be harnessed to produce useful energy.
  • the energy is harnessed by a water wheel or turbine, which may be used to generate electrical energy.
  • the method is preferably used to harness water wave energy.
  • the reservoirs are floated just below the surface of the water. Thus ensuring that they are subjected to less damage from the fluid than if situated at the surface.
  • apparatus for capturing the maximum or minimum fluid pressure of a fluid of fluctuating and variable pressure comprising a closed reservoir having a plurality of one-way valves arranged in a two- dimensional array on at least one of its surfaces such that when the pressure of external fluid differs from the pressure of fluid within the reservoir by a predetermined amount the pressure differential serves to open at least one of the valves so that fluid passes into or out of the reservoir via said valve, the pressure of the fluid in the reservoir tending to the maximum or minimum pressure of the external fluid.
  • the one-way valves are arranged to open inwards into the reservoir so that when the external fluid pressure at any point above the valves exceeds the fluid pressure inside the reservoir by said predetermined amount at least one of said valves opens to allow fluid into the reservoir, pressure of the fluid in the chamber tending to the maximum pressure of the external fluid.
  • the one-way valves may be arranged to open outwards of the reservoir so that when the fluid pressure inside the reservoir exceeds the external fluid pressure at any point at least one of said valves opens to allow fluid out of the reservoir, the pressure of the fluid in the chamber tending to the minimum pressure of the external fluid.
  • two such reservoirs are interconnected with a first of such reservoirs having one-way valves arranged to open inwards into the reservoir so that when the external fluid pressure at any point above the valves exceeds the fluid pressure inside ' the reservoir by said predetermined amount at least one of said valves opens to allow fluid into the reservoir, pressure of the fluid in the first reservoir tending to the maximum pressure of the external fluid and a second of such- reservoirs having one-way valves are arranged to open outwards of the reservoir so that when the fluid pressure inside the reservoir exceeds the external fluid pressure at any point at least one of said valves opens to allow fluid out of the reservoir, the pressure of the fluid in the second reservoir tending to the minimum pressure of the external fluid, the fluid in the first reservoir flowing into the second reservoir to eliminate the pressure differential between the reservoirs.
  • Means may be provided to harness the kinetic energy of the flow of fluid between the reservoirs.
  • the harnessing means is preferably a water wheel or turbine, which may be used to generate electrical energy.
  • first and second reservoirs share a common dividing wall.
  • the harnessing means may be located in the wall.
  • the apparatus may be used for harnessing water wave energy and a floating cradle may be provided so that the reservoirs are floated under the surface of the water.
  • Figure 1 is a diagrammatic perspective representation of apparatus according to an aspect of the present invention.
  • Figure 2 is a diagrammatic plan view of the apparatus of figure 1;
  • Figure 3 is a diagrammatic side view of the apparatus of figure 1;
  • Figure 4 is a diagrammatic end view of the apparatus of figure 1;
  • Figure 5 (a) is a diagrammatic plan view of a non-return valve used in the apparatus of figure 1;
  • Figure 5 (b) is a diagrammatic side view of a non-return valve used in the apparatus of figure 1 in the closed position;
  • Figure 5 (c) is a diagrammatic side view of a non-return valve used in the apparatus of figure 1 in the open position;
  • Figure 6 is a diagrammatic side view of the apparatus of figure 1 supported in a floating cradle.
  • Figure 7 is a diagrammatic plan view of the apparatus of figure 6.
  • the following description relates to means for harnessing water wave energy to provide electrical power, however it will be clear to those skilled in the art that the field of application of the present invention extends to any fluid system having a fluctuating and variable pressure in which it is desired to capture the maximum and/or minimum fluid pressure.
  • a single wave energy harnessing device of the present invention has an elongate high-pressure reservoir 1 with a plurality of non-return inlet valves 2 and an adjacent elongate low-pressure reservoir 3 with a plurality of non-return outlet valves 4.
  • the reservoirs share a common dividing wall 5 in which are located three water wheels 6.
  • the device is disposed below the surface of the sea and is designed to be as long as the greatest expected wavelength.
  • the inlet valves 2 of the high-pressure reservoir 1 are arranged in a two-dimensional array on the top side of the reservoir 1.
  • the outlet valves 4 of the low-pressure reservoir 3 are similarly arranged on the top side of the reservoir 3.
  • the valves 2, 4 may be simple flap valves made of a flexible plastics material, as illustrated in figures 5 (a) - (c) of the drawings.
  • Each valve 2, 4 is composed of a support 7, a flap 8 and a seat 9.
  • the flap 8 is connected to the support 7 and moves between closed (figure 5 (b)) and open (figure 5 (c)) positions in response to pressure differentials in the surrounding water.
  • the support 7 and seat 9 are attached to the inner surface of the top side of the reservoir 1, the flap 8 opening inwardly with respect to the reservoir 1 to admit water into the reservoir 1.
  • the support 7 and seat 9 are attached to the outer surface of the top side of the reservoir 3, the flap 8 now opening outwardly with respect to the reservoir 3 to release water from the reservoir 3.
  • Each of the inlet valves 2 in the high-pressure reservoir is opened when the water pressure above it is greater than that inside the reservoir 1. Water then passes in to the high-pressure reservoir 1 in the direction of arrow A in figure 1.
  • Each outlet valve 4 in the low-pressure reservoir 3 is opened when the pressure of the water inside the reservoir 3 exceeds that of the water above the respective valve.
  • the high-pressure reservoir 1 is in communication with the low-pressure reservoir 3 via a series of water wheels 6 located in the common dividing wall 5.
  • water wheels 6 located in the common dividing wall 5.
  • the output of the water wheels 6 can then be connected to a pump (not shown) that draws in water from the surroundings and expels it at high pressure to a turbine or other power-generating device (not shown). Other power- generation, devices will be manifest to the skilled person.
  • the operation of the device is cyclical as each wave peak and trough passes over the reservoirs.
  • a wave peak P approaches the high-pressure reservoir 1
  • the water pressure increases from X-R to a maximum pressure X directly under the peak P (R being the reduction of water pressure in the high-pressure reservoir from the previous cycle, as described below).
  • the external water pressure reaches X-R the. inlet valve or valves 2 immediately below the wave peak P open so as to allow relatively high-pressure water to enter the high-pressure reservoir 1.
  • the external water pressure rises to X and stops when it drops below the pressure of the collected water in the high-pressure reservoir 1 whereupon the valves 2 close.
  • The- working pressure for the water wheels 6 is the difference between the water pressure in the high-pressure reservoir 1 and that in the lower pressure reservoir 3 and is dependent on the height between the peaks and troughs of the passing waves.
  • the amount of water passing through the water wheels 6 will depend on their size, design, the height of and the differential pressure between wave peaks and troughs.
  • the power output of the wheels 6 will thus vary with wave activity.
  • a pump can be used to absorb this variation and supply a proportionate amount of water to a turbine or other power-generating device.
  • two-dimensional arrays of non-return valves 2, 4 takes account of the fact that a given wave peak or trough is not necessarily uniform across its width or length, but rather, the pressure under it is variable and fluctuating.
  • the arrangement allows pressure fluctuations transverse to the direction of travel of waves over the apparatus to be exploited in addition to pressure fluctuations between wave peaks and troughs as described above, thereby providing a more efficient system for harnessing wave energy.
  • the pressure in the high-pressure reservoir l ' will tend to the highest pressure in the variable pressure wave front and the pressure in the low- pressure reservoir 3 will tend to the lowest pressure in the variable pressure wave front.
  • a further advantage of using two-dimensional arrays of valves 2, 4 is that power output fluctuations are reduced over known prior art systems.
  • the device can be seated in a floating cradle as shown in figures 6 and 7.
  • the reservoirs 1, 3 are received in a cradle 10 to which is attached four floats 11.
  • Location maintaining drives 12 and swivel drives 13 are also provided on the cradle.
  • the floating cradle 10 enables the device to be positioned more easily and to be moved using the drives 12 and 13.
  • the cradle may thus be held on station by reference to a GPS system (not shown), and may be swivelled to keep the device in optimum alignment with the prevailing wave direction.
  • the floating cradle 10 may be tethered to the seabed by suitable mechanical means such as anchor cables (not shown) that may be alterable in length.
  • the depth at which the cradle holds the basic units may be controlled so that the outlet valves may be held very near to the surface under a wave trough by means of electronically controlled flotation devices.
  • compressed air tanks may be used to fill or empty the floats 11 to a desired amount.
  • Each- reservoir unit may be provided with buoyancy bags or tanks (not shown) so that they can easily be floated to the surface and removed from the cradle for repair and maintenance without the use of undersea divers.
  • An electrical generator may be placed on top of the floating cradle, which means that power generation may be carried out at sea, which is useful for some off-shore installations, or may be used to provide power for a floating warning light or buoy.
  • a generator may be placed out of the water, for example on a sea-going platform or on land. It therefore requires less protection against waves than if it was placed in the water, making the device more economical. Maintenance of the power-generating device is also easier if the device is placed in dry conditions.
  • the number and location of the water wheels in the dividing wall can be altered to suit a particular application.
  • the water wheels may be replaced by any suitable mechanical device for generating power such as, for example, a turbine.
  • the electricity generated by such a turbine could either be used on site, or transmitted to the land by any suitable means.
  • One method for transmission of the energy would be to use the electricity generated by the device to generate hydrogen gas by electrolysis, which could then be shipped or pumped to land for use as a fuel.
  • the non-return valves need not necessarily be arranged across the top surface of the high- and low-pressure reservoirs but, rather, at any suitable location where they will be acted upon by the changes in pressure created by the wave peaks and troughs.
  • the apparatus may be also made compact and streamlined, reducing drag so that it is more efficient than known designs.

Abstract

The present invention relates to a method and apparatus for capturing the fluid pressure of a fluid. The apparatus is submerged just below the surface of the fluid and comprises a first reservoir (1) in communication with a second reservoir (3) via a series of power generating devices (6). The first reservoir has a two-dimensional array of inlet valves (2) to admit fluid when the fluid pressure above the apparatus exceeds that in the first reservoir. The second reservoir has a two-­dimensional array of outlet valves (4) to release fluid when the fluid pressure above the apparatus is below that in the second reservoir. The power generating devices generate power in response to the flow of fluid from the first reservoir to the second reservoir caused by the difference in fluid pressure between the two reservoirs.

Description

SUBMERGED WAVE ENERGY TRANSFORMER
The present invention relates to a method and apparatus for capturing the fluid pressure of a fluid, more particularly, for capturing the maximum and/or minimum fluid pressure of a fluid of fluctuating and variable pressure, such as, for example, sea water.
My co-pending British Patent Application GB-A-9920714.4, describes a device for harnessing wave energy. This device is designed to float just below the surface of the water and comprises a high-pressure reservoir connected to a low-pressure reservoir via a power generator. The high- pressure reservoir has a line of non-return valves which admit water as a wave crest passes over the apparatus, and the low-pressure reservoir has a line of non-return valves to release water as a wave trough passes over the apparatus. The pressure differential set up between the two reservoirs is used to drive the power generator.
Whilst this device is satisfactory, it is desirable to increase its efficiency even further.
It is therefore an object of the present invention to provide means for capturing the maximum and/or minimum fluid pressure of a fluid of fluctuating and variable pressure of improved efficiency.
According to a first aspect of the present invention there is provided a method for capturing the maximum or minimum fluid pressure of a fluid of fluctuating and variable pressure, the method comprising the steps of submerging in the fluid a closed reservoir having a plurality of one-way valves arranged in a two-dimensional array on at least one of its surfaces such that when the pressure of external fluid differs from the pressure of fluid within the reservoir by a predetermined amount the pressure differential serves to open at least one of the valves so that fluid passes into or out of the reservoir via said valve, the pressure of the fluid in the reservoir tending to the maximum or minimum pressure of the external fluid.
Providing a two-dimensional array of valves in this way increases the efficiency with which the maximum or minimum fluid pressure can be captured from the fluid surrounding the reservoir. This method enables fluctuating and variable pressure differentials both parallel and transverse to the direction of travel of the fluid past the reservoir to be efficiently exploited. Preferably the one-way valves are arranged to open inwards into the reservoir so that when the external fluid pressure at any point above the valves exceeds the fluid pressure inside the reservoir by said predetermined amount at least one of said valves opens to allow fluid into the reservoir, pressure of the fluid in the chamber tending to the maximum pressure of the external fluid.
Alternatively, the one-way valves may be arranged to open outwards of the reservoir so that when the fluid pressure inside the reservoir exceeds the external fluid pressure at any point at least one of said valves opens to allow fluid out of the reservoir, the pressure of the fluid in the chamber tending to the minimum pressure of the external fluid.
Prefereably two such reservoirs are interconnected with a first of such reservoirs having one-way valves arranged to open inwards into the reservoir so that when the external fluid pressure at any point above the valves exceeds the fluid pressure inside the reservoir by said predetermined amount at least one of said valves opens to allow fluid into the reservoir, pressure of the fluid in the first reservoir tending to the maximum pressure of the external fluid and a second of such reservoirs having one-way valves are arranged to open outwards of the reservoir so that when the fluid pressure inside the reservoir exceeds the external fluid pressure at any point at least one of said valves opens to allow fluid out of the reservoir, the pressure of the fluid in the second reservoir tending to the minimum pressure of the external fluid, the fluid in the first reservoir flowing into the second reservoir to eliminate the pressure differential between the reservoirs.
The pressure in the first reservoir thus tends to the highest pressure in the variable pressure region and the pressure in the second reservoir tends to the lowest pressure in the variable pressure region. The fluid entering the first reservoir under, for example, a wave peak may be evacuated from the second reservoir half a wavelength later.
The kinetic energy of the flow of fluid between the reservoirs may be harnessed to produce useful energy. Preferably the energy is harnessed by a water wheel or turbine, which may be used to generate electrical energy.
The method is preferably used to harness water wave energy. Preferably the reservoirs are floated just below the surface of the water. Thus ensuring that they are subjected to less damage from the fluid than if situated at the surface.
According to a second aspect of the present invention there is provided apparatus for capturing the maximum or minimum fluid pressure of a fluid of fluctuating and variable pressure, comprising a closed reservoir having a plurality of one-way valves arranged in a two- dimensional array on at least one of its surfaces such that when the pressure of external fluid differs from the pressure of fluid within the reservoir by a predetermined amount the pressure differential serves to open at least one of the valves so that fluid passes into or out of the reservoir via said valve, the pressure of the fluid in the reservoir tending to the maximum or minimum pressure of the external fluid.
Preferably the one-way valves are arranged to open inwards into the reservoir so that when the external fluid pressure at any point above the valves exceeds the fluid pressure inside the reservoir by said predetermined amount at least one of said valves opens to allow fluid into the reservoir, pressure of the fluid in the chamber tending to the maximum pressure of the external fluid.
Alternatively, the one-way valves may be arranged to open outwards of the reservoir so that when the fluid pressure inside the reservoir exceeds the external fluid pressure at any point at least one of said valves opens to allow fluid out of the reservoir, the pressure of the fluid in the chamber tending to the minimum pressure of the external fluid.
Preferably two such reservoirs are interconnected with a first of such reservoirs having one-way valves arranged to open inwards into the reservoir so that when the external fluid pressure at any point above the valves exceeds the fluid pressure inside' the reservoir by said predetermined amount at least one of said valves opens to allow fluid into the reservoir, pressure of the fluid in the first reservoir tending to the maximum pressure of the external fluid and a second of such- reservoirs having one-way valves are arranged to open outwards of the reservoir so that when the fluid pressure inside the reservoir exceeds the external fluid pressure at any point at least one of said valves opens to allow fluid out of the reservoir, the pressure of the fluid in the second reservoir tending to the minimum pressure of the external fluid, the fluid in the first reservoir flowing into the second reservoir to eliminate the pressure differential between the reservoirs. Means may be provided to harness the kinetic energy of the flow of fluid between the reservoirs. The harnessing means is preferably a water wheel or turbine, which may be used to generate electrical energy.
Preferably the first and second reservoirs share a common dividing wall. The harnessing means may be located in the wall.
The apparatus may be used for harnessing water wave energy and a floating cradle may be provided so that the reservoirs are floated under the surface of the water.
A specific embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which:
Figure 1 is a diagrammatic perspective representation of apparatus according to an aspect of the present invention;
Figure 2 is a diagrammatic plan view of the apparatus of figure 1;
Figure 3 is a diagrammatic side view of the apparatus of figure 1;
Figure 4 is a diagrammatic end view of the apparatus of figure 1;
Figure 5 (a) is a diagrammatic plan view of a non-return valve used in the apparatus of figure 1;
Figure 5 (b) is a diagrammatic side view of a non-return valve used in the apparatus of figure 1 in the closed position;
Figure 5 (c) is a diagrammatic side view of a non-return valve used in the apparatus of figure 1 in the open position;
Figure 6 is a diagrammatic side view of the apparatus of figure 1 supported in a floating cradle; and
Figure 7 is a diagrammatic plan view of the apparatus of figure 6. The following description relates to means for harnessing water wave energy to provide electrical power, however it will be clear to those skilled in the art that the field of application of the present invention extends to any fluid system having a fluctuating and variable pressure in which it is desired to capture the maximum and/or minimum fluid pressure.
Referring now to figures 1 to 4 of the drawings, a single wave energy harnessing device of the present invention has an elongate high-pressure reservoir 1 with a plurality of non-return inlet valves 2 and an adjacent elongate low-pressure reservoir 3 with a plurality of non-return outlet valves 4. The reservoirs share a common dividing wall 5 in which are located three water wheels 6. The device is disposed below the surface of the sea and is designed to be as long as the greatest expected wavelength.
The inlet valves 2 of the high-pressure reservoir 1 are arranged in a two-dimensional array on the top side of the reservoir 1. The outlet valves 4 of the low-pressure reservoir 3 are similarly arranged on the top side of the reservoir 3.
The valves 2, 4 may be simple flap valves made of a flexible plastics material, as illustrated in figures 5 (a) - (c) of the drawings. Each valve 2, 4 is composed of a support 7, a flap 8 and a seat 9. The flap 8 is connected to the support 7 and moves between closed (figure 5 (b)) and open (figure 5 (c)) positions in response to pressure differentials in the surrounding water. In the case of the inlet valves 2, the support 7 and seat 9 are attached to the inner surface of the top side of the reservoir 1, the flap 8 opening inwardly with respect to the reservoir 1 to admit water into the reservoir 1. Conversely, in the case of the outlet valves 4, the support 7 and seat 9 are attached to the outer surface of the top side of the reservoir 3, the flap 8 now opening outwardly with respect to the reservoir 3 to release water from the reservoir 3.
Each of the inlet valves 2 in the high-pressure reservoir is opened when the water pressure above it is greater than that inside the reservoir 1. Water then passes in to the high-pressure reservoir 1 in the direction of arrow A in figure 1. Each outlet valve 4 in the low-pressure reservoir 3 is opened when the pressure of the water inside the reservoir 3 exceeds that of the water above the respective valve. The high-pressure reservoir 1 is in communication with the low-pressure reservoir 3 via a series of water wheels 6 located in the common dividing wall 5. When the pressure of water in the high-pressure reservoir 1 is greater than that in the low-pressure reservoir 3 water passes through the water wheels 6 in the direction of arrow C in figure 4. The output of the water wheels 6 can then be connected to a pump (not shown) that draws in water from the surroundings and expels it at high pressure to a turbine or other power-generating device (not shown). Other power- generation, devices will be manifest to the skilled person.
The operation of the device is cyclical as each wave peak and trough passes over the reservoirs. When a wave peak P approaches the high-pressure reservoir 1, the water pressure increases from X-R to a maximum pressure X directly under the peak P (R being the reduction of water pressure in the high-pressure reservoir from the previous cycle, as described below). When the external water pressure reaches X-R the. inlet valve or valves 2 immediately below the wave peak P open so as to allow relatively high-pressure water to enter the high-pressure reservoir 1. This continues while the external water pressure rises to X and stops when it drops below the pressure of the collected water in the high-pressure reservoir 1 whereupon the valves 2 close. This process is repeated for other inlet valves 2 along the length of the reservoir as the wave peak P moves over them and the maximum pressure in the high-pressure reservoir 1 thus tends to X. Since the reservoir is as long as the greatest expected wavelength, at least one inlet valve 2 will be open at any point in time in the cycle.
At the same time as the high-pressure reservoir 1 is being filled a wave trough T approaches the device and the external water pressure decreases from Y+S (S being the increase in pressure of the water in the low-pressure from the last cycle, as described below) to a minimum pressure Y directly under the trough T. When the external water pressure reaches Y+S the underlying outlet valve or valves 4 are forced open and the water inside the low-pressure reservoir 3 is thus discharged to the surroundings. This continues while the pressure of the surrounding water drops to Y and stops when it rises above the pressure of the water in the low-pressure reservoir 3, whereupon the valves 4 close. This process is repeated for other outlet valves 4 along the length of the reservoir resulting in the pressure of the water in the low-pressure reservoir 3 tending towards Y. Again, since the device is as long as the wavelength at least one outlet valve 4 is always open. As water passes from one reservoir to the other, the pressure of the water in the high-pressure reservoir 1 drops by R and the water pressure in the low-pressure reservoir 3 increases by S. The used water is then released to the surroundings as the wave trough T passes.
After the wave peak P has passed the inlet valves 2 in the high-pressure reservoir 1 they remain closed until the next peak approaches and the pressure of the sμrrounding water reaches X-R again. Similarly, after the wave trough T has passed the outlet valves 4 in the low-pressure reservoir 3 they remain closed until the next trough T approaches and the pressure drops to Y+S again.
The- working pressure for the water wheels 6 is the difference between the water pressure in the high-pressure reservoir 1 and that in the lower pressure reservoir 3 and is dependent on the height between the peaks and troughs of the passing waves.
The amount of water passing through the water wheels 6 will depend on their size, design, the height of and the differential pressure between wave peaks and troughs. The power output of the wheels 6 will thus vary with wave activity. A pump can be used to absorb this variation and supply a proportionate amount of water to a turbine or other power-generating device.
The use of two-dimensional arrays of non-return valves 2, 4 takes account of the fact that a given wave peak or trough is not necessarily uniform across its width or length, but rather, the pressure under it is variable and fluctuating. The arrangement allows pressure fluctuations transverse to the direction of travel of waves over the apparatus to be exploited in addition to pressure fluctuations between wave peaks and troughs as described above, thereby providing a more efficient system for harnessing wave energy. The pressure in the high-pressure reservoir l 'will tend to the highest pressure in the variable pressure wave front and the pressure in the low- pressure reservoir 3 will tend to the lowest pressure in the variable pressure wave front. A further advantage of using two-dimensional arrays of valves 2, 4 is that power output fluctuations are reduced over known prior art systems.
It will be understood that by operating under the surface of the water, where the conditions are more favourable than at the surface, the device is more efficient than many known designs. The closer the device is to the surface of the water the more efficient it will be. This is because the efficiency of flow of the water between the reservoirs is dependent on the ratio C+D : D where C is the increase in water pressure as a result of the wave peak and D is the water pressure provided by the column of water and atmospheric pressure that is always above the device.
In order to exploit the increased efficiency immediately below the water surface the device can be seated in a floating cradle as shown in figures 6 and 7. The reservoirs 1, 3 are received in a cradle 10 to which is attached four floats 11. Location maintaining drives 12 and swivel drives 13 are also provided on the cradle. The floating cradle 10 enables the device to be positioned more easily and to be moved using the drives 12 and 13. The cradle may thus be held on station by reference to a GPS system (not shown), and may be swivelled to keep the device in optimum alignment with the prevailing wave direction. The floating cradle 10 may be tethered to the seabed by suitable mechanical means such as anchor cables (not shown) that may be alterable in length. The depth at which the cradle holds the basic units may be controlled so that the outlet valves may be held very near to the surface under a wave trough by means of electronically controlled flotation devices. For example, compressed air tanks may be used to fill or empty the floats 11 to a desired amount.
Each- reservoir unit may be provided with buoyancy bags or tanks (not shown) so that they can easily be floated to the surface and removed from the cradle for repair and maintenance without the use of undersea divers.
An electrical generator may be placed on top of the floating cradle, which means that power generation may be carried out at sea, which is useful for some off-shore installations, or may be used to provide power for a floating warning light or buoy.
Alternatively, a generator may be placed out of the water, for example on a sea-going platform or on land. It therefore requires less protection against waves than if it was placed in the water, making the device more economical. Maintenance of the power-generating device is also easier if the device is placed in dry conditions.
It will be appreciated that numerous modifications to the above described design may be made without departing from the scope of the invention as defined in the appended claims. For example, the number and location of the water wheels in the dividing wall can be altered to suit a particular application. Furthermore, the water wheels may be replaced by any suitable mechanical device for generating power such as, for example, a turbine. The electricity generated by such a turbine could either be used on site, or transmitted to the land by any suitable means. One method for transmission of the energy would be to use the electricity generated by the device to generate hydrogen gas by electrolysis, which could then be shipped or pumped to land for use as a fuel.
The non-return valves need not necessarily be arranged across the top surface of the high- and low-pressure reservoirs but, rather, at any suitable location where they will be acted upon by the changes in pressure created by the wave peaks and troughs. The apparatus may be also made compact and streamlined, reducing drag so that it is more efficient than known designs.

Claims

1. A method for capturing the maximum or minimum fluid pressure of a fluid of fluctuating and variable pressure, the method comprising the steps of submerging in the fluid a closed reservoir having a plurality of one-way valves arranged in a two-dimensional array on at least one of its surfaces such that when the pressure of external fluid differs from the pressure of fluid within the reservoir by a predetermined amount the pressure differential serves to open at least one of the valves so that fluid passes into or out of the reservoir via said valve, the pressure of the fluid in the reseivoir tending to the maximum or minimum pressure of the external fluid.
2. A method according to claim 1, wherein the one-way valves are arranged to open inwards into the reservoir so that when the external fluid pressure at any point above the valves exceeds the fluid pressure inside the reservoir by said predetermined amount at least one of said valves opens to allow fluid into the reservoir, pressure of the fluid in the chamber tending to the maximum pressure of the external fluid.
3. A method according to claim 1, wherein the one-way valves are arranged to open outwards of the reservoir so that when the fluid pressure inside the reservoir exceeds the external fluid pressure at any point at least one of said valves opens to allow fluid out of the reservoir, the pressure of the fluid in the chamber tending to the minimum pressure of the external fluid.
4. A method according to claim 1, wherein two such reservoirs are interconnected with a first of such reservoirs having one-way valves arranged to open inwards into the reservoir so that when the external fluid pressure at any point above the valves exceeds the fluid pressure inside the reservoir by said predetermined amount at least one of said valves opens to allow fluid into the reservoir, pressure of the fluid in the first reservoir tending to the maximum pressure of the external fluid and a second of such reservoirs having one-way valves are arranged to open outwards of the reseivoir so that when the fluid pressure inside the reservoir exceeds the external fluid pressure at any point at least one of said valves opens to allow fluid out of the reservoir, the pressure of the fluid in the second reservoir tending to the minimum pressure of the external fluid, the fluid in the first reservoir flowing into the second reservoir to eliminate the pressure differential between the reservoirs.
5. A method according to claim 4, wherein the kinetic energy of the flow of fluid between the reservoirs is harnessed to produce useful energy.
6. A method according to claim 5, wherein the energy is harnessed by a water wheel or turbine.
7. A method according to claim 6, wherein the water wheel or turbine is used to generate electrical energy.
8. A method according to any one of claims 4 to 6, wherein the method is used to harness water wave energy.
9. A method according to claim 8, wherein the reservoirs are floated just below the surface of the water.
10. Apparatus for capturing the maximum or minimum fluid pressure of a fluid of fluctuating and variable pressure, comprising a closed reservoir having a plurality of one-way valves arranged in a two-dimensional array on at least one of its surfaces such that when the pressure of external fluid differs from the pressure of fluid within the reservoir by a predetermined amount the pressure differential serves to open at least one of the valves so that fluid passes into or out of the reservoir via said valve, the pressure of the fluid in the reservoir tending to the maximum or minimum pressure of the external fluid.
11. Apparatus according to claim 10, wherein the one-way valves are arranged to open inwards into the reservoir so that when the external fluid pressure at any point above the valves exceeds the fluid pressure inside the reservoir by said predetermined amount at least one of said valves opens to allow fluid into the reservoir, pressure of the fluid in the chamber tending to the maximum pressure of the external fluid.
12. Apparatus according to claim 11, wherein the one-way valves are arranged to open outwards of the reservoir so that when the fluid pressure inside the reservoir exceeds the external fluid pressure at any point at least one of said valves opens to allow fluid out of the reservoir, the pressure of the fluid in the chamber tending to the minimum pressure of the external fluid.
3. Apparatus according to claim 11, wherein two such reservoirs are interconnected with a first of such reservoirs having one-way valves arranged to open inwards into the reservoir so that when the external fluid pressure at any point above the valves exceeds the fluid pressure inside the reservoir by said predetermined amount at least one of said valves opens to allow fluid into the reseivoir, pressure of the fluid in the first reservoir tending to the maximum pressure of the external fluid and a second of such reservoirs having one-way valves are arranged to open outwards of the reservoir so that when the fluid pressure inside the reservoir exceeds the external fluid pressure at any point at least one of said valves opens to allow fluid out of the reservoir, the pressure of the fluid in the second reservoir tending to the minimum pressure of the external fluid, the fluid in the first reservoir flowing into the second reservoir to eliminate the pressure differential between the reservoirs.
14. Apparatus according to claim 13, wherein means are provided to harness the kinetic energy of the flow of fluid between the reservoirs.
15. Apparatus according to claim 14, wherein the harnessing means is a water wheel or turbine.
16. Apparatus according to claim 15, wherein the water wheel or turbine is used to generate ' electrical energy.
17. Apparatus according to any one of claims 11 to 17, wherein the first and second reservoirs share a common dividing wall.
18. Apparatus according to claim 17 when dependent from claim 15, wherein the harnessing means is located in the wall.
19. Apparatus for harnessing water wave energy according to any one of claims 11 to 18.
20. Apparatus according to claim 19, wherein there is provided a floating cradle so that the reservoirs are floated under the surface of the water.
21. A method substantially as hereinbefore described with reference to the accompanying drawings.
2. An apparatus substantially as hereinbefore described with reference to the accompanying drawings.
PCT/GB2003/001031 2002-03-16 2003-03-11 Submerged wave energy transformer WO2003078831A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
GB0418921A GB2401155A (en) 2002-03-16 2003-03-11 Submerged wave energy transformer
AU2003212523A AU2003212523A1 (en) 2002-03-16 2003-03-11 Submerged wave energy transformer

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB0206403.8 2002-03-16
GBGB0206403.8A GB0206403D0 (en) 2002-03-16 2002-03-16 Method and apparatus for capturing the fluid pressure of a fluid

Publications (1)

Publication Number Publication Date
WO2003078831A1 true WO2003078831A1 (en) 2003-09-25

Family

ID=9933234

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB2003/001031 WO2003078831A1 (en) 2002-03-16 2003-03-11 Submerged wave energy transformer

Country Status (3)

Country Link
AU (1) AU2003212523A1 (en)
GB (2) GB0206403D0 (en)
WO (1) WO2003078831A1 (en)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006102694A1 (en) * 2005-04-01 2006-10-05 Jianfeng Su Wave power converter
WO2010139332A3 (en) * 2009-06-03 2011-06-23 I/S Boewind V/Chr. Kjaer An assembly for utilizing wave energy as well as a method and use
US20120032444A1 (en) * 2010-08-06 2012-02-09 John Alan Burton Wave Catcher
PT105681A (en) * 2011-05-08 2012-11-08 Jose Paulo Pereira De Gouveia Lopes De Almeida DIFFERENTIAL HYDROELECTRIC GENERATOR THE WAVE ENERGY
WO2015072869A1 (en) 2013-11-12 2015-05-21 Universidade De Coimbra Artificial coastal-protection reef with energy generation unit with or without direct contact with seawater
WO2015192258A1 (en) * 2014-06-18 2015-12-23 Etymol Ocean Power Spa Autonomous submarine apparatus for utilizing wave energy
US9546550B2 (en) 2012-04-23 2017-01-17 Thomas Francis Landon Bypass foil
US10989164B2 (en) 2018-03-05 2021-04-27 Richard W. Carter Resonant unidirectional wave energy converter
US20220082075A1 (en) * 2020-09-16 2022-03-17 Ginjirou Onda Wave force utilization unit and wave force utilization system using same

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB0226725D0 (en) 2002-11-15 2002-12-24 Bp Exploration Operating method

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1513874A (en) * 1923-12-29 1924-11-04 Morrell J Ufford Wave motor
GB2005358A (en) * 1977-10-03 1979-04-19 Hawes R A Utilising wave energy
WO2000017518A1 (en) * 1998-09-17 2000-03-30 Alexander George Southcombe Apparatus for harnessing wave energy

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1513874A (en) * 1923-12-29 1924-11-04 Morrell J Ufford Wave motor
GB2005358A (en) * 1977-10-03 1979-04-19 Hawes R A Utilising wave energy
WO2000017518A1 (en) * 1998-09-17 2000-03-30 Alexander George Southcombe Apparatus for harnessing wave energy

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006102694A1 (en) * 2005-04-01 2006-10-05 Jianfeng Su Wave power converter
WO2010139332A3 (en) * 2009-06-03 2011-06-23 I/S Boewind V/Chr. Kjaer An assembly for utilizing wave energy as well as a method and use
US20120032444A1 (en) * 2010-08-06 2012-02-09 John Alan Burton Wave Catcher
PT105681A (en) * 2011-05-08 2012-11-08 Jose Paulo Pereira De Gouveia Lopes De Almeida DIFFERENTIAL HYDROELECTRIC GENERATOR THE WAVE ENERGY
US9546550B2 (en) 2012-04-23 2017-01-17 Thomas Francis Landon Bypass foil
WO2015072869A1 (en) 2013-11-12 2015-05-21 Universidade De Coimbra Artificial coastal-protection reef with energy generation unit with or without direct contact with seawater
US10233894B2 (en) 2013-11-12 2019-03-19 Universidade De Coimbra Artificial coastal-protection reef with energy generation unit with or without direct contact with seawater
WO2015192258A1 (en) * 2014-06-18 2015-12-23 Etymol Ocean Power Spa Autonomous submarine apparatus for utilizing wave energy
US10989164B2 (en) 2018-03-05 2021-04-27 Richard W. Carter Resonant unidirectional wave energy converter
US20220082075A1 (en) * 2020-09-16 2022-03-17 Ginjirou Onda Wave force utilization unit and wave force utilization system using same
US11913422B2 (en) * 2020-09-16 2024-02-27 Ginjirou Onda Wave force utilization unit and wave force utilization system using same

Also Published As

Publication number Publication date
GB0418921D0 (en) 2004-09-29
GB0206403D0 (en) 2002-05-01
GB2401155A (en) 2004-11-03
AU2003212523A1 (en) 2003-09-29

Similar Documents

Publication Publication Date Title
KR101354182B1 (en) Apparatus for generating electricity using tidal or current flow
US7339285B2 (en) Hydroelectric wave-energy conversion system
US7755211B2 (en) Rigid structural array
US7980832B2 (en) Wave energy converter
EP2585711B1 (en) Ocean wave energy system
US6388342B1 (en) Hydro electric plant
EP1915528B1 (en) Free floating wave energy converter
US20120032444A1 (en) Wave Catcher
US8035243B1 (en) System to obtain energy from water waves
US20100244451A1 (en) Ocean wave energy to electricity generator
KR20090038455A (en) Wave energy converter
WO2010051630A1 (en) Buoyancy energy storage and energy generation system
US8424300B1 (en) Sea electricity energy production unit
KR20110021086A (en) Apparatus for using waves energy
US20120131914A1 (en) Power Generation System
US8899036B2 (en) Advanced high energy wave power module
US20090261593A1 (en) Tidal pump generator
CN108603481B (en) Wide wave spectrum wave energy recovery device
US20110225965A1 (en) Wave energy convertor
JPH0686862B2 (en) Device and method for generating electric power from ocean waves
WO2003078831A1 (en) Submerged wave energy transformer
US20220002170A1 (en) Sea water de-salination methods and apparatuses
RU2150021C1 (en) Method and megawatt-capacity power-plant module for recovering energy of reusable sources (options)
JP2016517923A (en) Submersible hydroelectric generator device and method for draining water from such device
WO1998032967A1 (en) Wave energy converter

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EC EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NI NO NZ OM PH PL PT RO RU SC SD SE SG SK SL TJ TM TN TR TT TZ UA UG US UZ VC VN YU ZA ZM ZW

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LU MC NL PT RO SE SI SK TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG

ENP Entry into the national phase

Ref document number: 0418921

Country of ref document: GB

Kind code of ref document: A

Free format text: PCT FILING DATE = 20030311

121 Ep: the epo has been informed by wipo that ep was designated in this application
DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase

Ref country code: JP

WWW Wipo information: withdrawn in national office

Country of ref document: JP