2

3 The present invention relates to an energy harvesting device, system and method of

4 manufacture. In particular, the described device is suitable for harvesting kinetic energy

5 from a fluid flow and or a liquid e.g. a water wave to produce renewal energy.

6

7 Background to the Invention

8

9 There are numerous forms of coastal defences which defend land from erosion and0 flooding. A seawall is a form of coastal defence constructed along the interface between1 the sea and land. A seawall provides a barrier reflecting and dissipating incident waves2 thereby protecting the land. A seawall is designed to withstand the kinetic energy from the3 waves as well as the continuous and unrelenting nature of the waves. 4 5 Whilst seawalls provide a strong and long-term coastal defence, seawalls can be 6 expensive to construct, aesthetically unattractive, disrupt the natural habitats and alter7 sediment transport. However, a key disadvantage of well-known seawall designs is that8 whilst they redirect and or dissipate the kinetic energy of a wave, they do not harvest the9 kinetic energy of the wave.

2

3 It is an object of an aspect of the present invention to provide an energy harvesting device

4 that obviates or at least mitigates one or more of the aforesaid disadvantages of the

5 devices known in the art.

6

7 According to a first aspect of the present invention there is provided an energy harvesting

8 device comprising:

9 one or more membranes; 0 an energy conversion means employed to convert movement of the one or more1 membranes into electricity; and 2 one or more vibrational lenses connecting the one or more membranes to the energy3 conversion means. 4 5 Preferably, the energy harvesting device further comprises a duct and the one or more6 membranes are located within the duct. 7 8 Preferably, the duct extends between an inlet opening on a first surface and a first outlet9 opening on a second surface. 0 1 Most preferably, the one or more membranes are configured to move in response to a fluid2 flow through the duct and or a compression wave traversing the duct. The fluid flow may3 take the form of a gas flow or liquid flow. The compression wave may take the form of a4 compression wave in a gas or liquid. 5 6 Preferably, each of the one or more membranes comprises one or more members. Each7 of the one or more membrane may be a mesh or fabric formed of the one or more 8 members. 9 0 Preferably, the one or more membranes are orientated to extend across at least a portion1 of the duct’s cross-sectional area. The one or more membranes are orientated 2 substantially perpendicular to a central axis of the duct. 3 4 Preferably, the energy harvesting device may comprise two or more sets of one or more5 membranes, each set located at different locations within the duct. 1

2 Alternatively, the one or more membranes may be orientated parallel to a central axis of a

3 duct. The one or more membranes may be mounted on a support structure. The support

4 structure is attached to a duct wall.

5

6 Optionally, the one or more membranes may be mounted on multiple surfaces of the

7 support structure.

8

9 Optionally, the energy harvesting device may further comprise one or more sticks each0 pivotally mounted to a mast extending orthogonally from the membranes towards the1 central axis of the duct. In operation, the one or more sticks are configured to strike the2 membrane enhancing the movement of the membrane. 3 4 Most preferably, each of the one or more vibrational lens comprises at least two focusing5 members, each of the at least two focusing members having a first end for attachment to6 the one or more membranes and a second end located at which is the energy conversion7 means, wherein the at least two focusing members are arranged such that the separation8 between the focusing members decreases from the first ends towards the second ends. 9 0 Most preferably, the one or more vibrational lenses capture, transmit, converge and or1 focus the movement from the one or more membranes to the energy conversion means. 2 3 Optionally, each of the one or more vibrational lens comprises a plurality of focusing4 members wherein two or more membranes may be attached to each of the one or more5 vibrational lenses. 6 7 Preferably, the energy conversion means is a magnet and coil. 8 9 Alternatively, the energy conversion means is a piezoelectric crystal. 0 1 Preferably, the one or more vibrational lenses and energy conversion means are located2 within the energy harvesting device but not within the duct. The one or more vibrational3 lenses pass through the duct wall to connect to the one or more membranes. The one or4 more vibrational lenses pass through the duct wall by means of a fluid tight bearing. 5 1 Optionally, the energy harvesting device further comprises a passageway connecting the

2 duct to a second outlet opening.

3

4 Preferably, the energy harvesting device further comprises two or more ducts. Preferably

5 each of the two or more ducts comprise one or more membranes within the duct.

6

7 Preferably, the energy harvesting device is suitable to be located at the interface between

8 sea and land, submerged undersea and or on land.

9 0 Optionally, the one or more membranes may be located on one or more external surfaces1 of the energy harvesting device. The one or more membranes may be substantially2 parallel to the one or more external surfaces. The one or more membranes are configured3 to be actuated by a fluid flow incident upon and or traversing parallel to the external4 surface. 5 6 According to a second aspect of the present invention there is provided an energy7 harvesting system comprising two or more energy harvesting devices in accordance with8 the first aspect of the present invention. 9 0 Preferably, the two or more energy harvesting devices are stacked side-by-side and or1 upon each other. The two or more energy harvesting devices can be combined to make a2 wall, such as a seawall. 3 4 Embodiments of the second aspect of the invention may comprise features to implement5 the preferred or optional features of the first aspect of the invention or vice versa. 6 7 According to a third aspect of the present invention there is provided a method of 8 manufacturing an energy harvesting device comprising: 9 providing one or more membranes; 0 providing an energy conversion means employed to convert the movement of the1 one or more membranes into electricity; and 2 providing one or more vibrational lenses connecting the one or more membranes to3 the energy conversion means. 1 Most preferably, the method of manufacturing an energy harvesting device further

2 comprises providing a duct and the one or more membranes are located within the duct.

3

4 Most preferably, the method of manufacturing an energy harvesting device further

5 comprises characterising a fluid flow.

6

7 Preferably, characterising a fluid flow comprises characterising the medium, the mean fluid

8 flow speed, fluid flow speed distribution, turbulence, fluid flow shear profile, distribution of

9 fluid flow direction and long-term temporal fluid flow variations. 0 1 Most preferably, the method of manufacturing an energy harvesting device further2 comprises characterising a compression wave. 3 4 Preferably, characterising a compression wave comprises the frequency, amplitude,5 wavelength and speed. 6 7 Most preferably, the method of manufacturing an energy harvesting device further8 comprises determining the optimum parameters of the energy harvesting device for use9 with the fluid flow and or compression wave. 0 1 Preferably, determining the optimum parameters of the energy harvesting device 2 comprises determining: the dimensions of the energy harvesting device; the dimension3 and shape of the duct; the dimension and shape of a passageway and if the passageway4 is required; the number, dimension, shape, material composition, structure, orientation and5 arrangement of the one or more membranes; and the dimension, shape, material6 composition, orientation and arrangement of the one or more vibrational lenses. 7 8 Embodiments of the third aspect of the invention may comprise features to implement the9 preferred or optional features of the first and or second aspects of the invention or vice0 versa. 1 2 According to a fourth aspect of the present invention there is provided a use of an energy3 harvesting device in accordance with the first aspect of the present invention, or an energy4 harvesting system in accordance with the second aspect of the present invention, for5 generating electrical energy. 1

2 Embodiments of the fourth aspect of the invention may comprise features to implement the

3 preferred or optional features of the first, second and/or third aspects of the invention or

4 vice versa.

5

6 According to a fifth aspect of the present invention there is provided an energy harvesting

7 device comprising:

8 a duct with an inlet opening and an outlet opening;

9 one or more membranes located within the duct; 0 an energy conversion means employed to convert movement of the one or more1 membranes into electricity; and 2 one or more vibrational lenses connecting the one or more membranes to the energy3 conversion means. 4 5 Preferably, the movement of the one or more membranes is induced by a vibrational and6 or a percussive and or ballistic and or collisional interaction with a fluid flow and or a7 compression wave. 8 9 Preferably, the movement of the one or more membranes is induced by a fluid flow and or0 compression wave without generating lift. 1 2 Optionally, each of the one or more vibrational lens comprises at least two focusing3 members, each of the at least two focusing members having a first end for attachment to4 the one or more membranes and a second end located at which is the energy conversion5 means, preferably the at least two focusing members are arranged such that the 6 separation between the focusing members decreases from the first ends towards the7 second. 8 9 Embodiments of the fifth aspect of the invention may comprise features to implement the0 preferred or optional features of the first, second, third and/or fourth aspects of the1 invention or vice versa. 2 3 1 Brief of Drawinas

2

3 There will now be described, by way of example only, various embodiments of the

4 invention with reference to the drawings, of which:

5

6 Figure 1 presents a schematic cross-sectional view of an energy harvesting device in

7 accordance with an embodiment of the present invention;

8

9 Figure 2 presents a schematic cross-sectional view of (a) a membrane of the energy0 harvesting device of Figure 1 , and (b) a membrane of an alternative embodiment of the1 energy harvesting device of Figure 1 ; 2 3 Figure 3 presents a schematic cross-sectional view of the energy harvesting device of4 Figure 1 focused on an arrangement of membranes; 5 6 Figure 4 presents a schematic cross-sectional view of (a) an energy conversion means of7 the energy harvesting device of Figure 1 and (b) an energy conversion means of an8 alternative embodiment of the energy harvesting device of Figure 1 ; 9 0 Figure 5 presents a perspective view of an energy harvesting system comprising the1 energy harvesting device of Figure 1 ; 2 3 Figure 6 presents a schematic cross-sectional view of an alternative embodiment of the4 energy harvesting device of Figure 1 ; 5 6 Figure 7 presents a schematic cross-sectional view of a further alternative embodiment of7 the energy harvesting device of Figure 1 ; 8 9 Figure 8 presents a perspective view of an alternative embodiment of the energy 0 harvesting device of Figure 1 ; 1 2 Figure 9 presents a perspective view of another alternative embodiment of the energy3 harvesting device of Figure 1 ; 4 1 Figure 10 presents a schematic cross-sectional view of an alternative embodiment of the

2 energy harvesting device of Figure 1 ;

3

4 Figure 11 presents a schematic cross-sectional view of a membrane arrangement of the

5 energy harvesting device of Figure 10;

6

7 Figure 12 presents a schematic cross-sectional view of an alternative embodiment of the

8 energy harvesting device of Figure 1 ;

9 0 Figure 13 presents a schematic cross-sectional view of an alternative embodiment of the1 energy harvesting device of Figure 1 ; 2 3 Figure 14 presents a schematic cross-sectional view of a further alternative embodiment of4 the energy harvesting device of Figure 1 ; 5 6 Figure 15 presents a schematic cross-sectional view of another alternative embodiment of7 the energy harvesting device of Figure 1 ; 8 9 Figure 16 presents a schematic cross-sectional view of an alternative embodiment of the0 energy harvesting device of Figure 1 ; 1 2 Figure 17 presents a perspective view of the alternative embodiment of the energy3 harvesting device of Figure 16; and 4 5 Figure 18 presents a flow chart of the method of manufacturing the energy harvesting6 device of Figure 1. 7 8 In the description which follows, like parts are marked throughout the specification and9 drawings with the same reference numerals. The drawings are not necessarily to scale0 and the proportions of certain parts have been exaggerated to better illustrate details and1 features of embodiments of the invention. 2 3 1 Detailed of the Preferred Embodiments

2

3 An explanation of the present invention will now be described with reference to Figures 1

4 to 18.

5

6 Energy Harvesting Device

7

8 Figure 1 depicts an energy harvesting device 1 a comprising a duct 2 with an inlet opening

9 3 and a first outlet opening 4. The energy harvesting device 1a is suitable for harvesting0 energy from a fluid flow 5 and or a compression wave 6 traversing the duct 2. It will be1 appreciated the fluid flow 5 could take the form of a gas flow or a liquid flow. Furthermore,2 the compression wave 6 could take form of a compression wave in a gas or liquid. For3 ease of understanding, Figure 1 depicts a cartesian coordinate system with x, y, and z4 axes. Furthermore Figure 1 also depicts a central axis 7 of the duct 2, in other words, an5 axis extending longitudinally through the duct 2. 6 7 The energy harvesting device 1a is substantially cuboid as will be understood by the8 rectangular cross-section in the y-z plane depicted in Figure 1 . The energy harvesting9 device 1a comprises a first surface 8 and a second surface 9. The duct 2 extends 0 between the inlet opening 3 on the first surface 8 to the first outlet opening 4 on the1 second surface 9. 2 3 As can be seen in Figure 1 , the first surface 8 takes the form of a side surface of the4 energy harvesting device 1a and the second surface 9 takes the form of the top surface of5 the energy harvesting device 1 a. As such, the duct 2 comprises a bend 10 to connect the6 first and second surfaces 8, 9. It will be appreciated that the energy harvesting device 1a7 may take the form of any regular or irregular shape with the duct 2 extending between any8 two surfaces or between any two regions of a surface. 9 0 The duct 2 shown in Figure 1 has a substantially circular cross-sectional shape. However,1 it will be appreciated that the duct may have any suitable cross-sectional shape. 2 3 The energy harvesting device 1a further comprises a passageway 11 connecting the duct4 2 to a second outlet opening 12 on a third surface 13. The passageway 11 may have a 1 different cross-sectional size and or shape in comparison to the duct 2. The third surface

2 13 takes the form of the bottom surface of the energy harvesting device 1a.

3

4 Membranes

5

6 The energy harvesting device 1a comprises one or more membranes 14, located within

7 the duct 2. As an example, Figure 1 depicts ten membranes 14 located within the duct 2.

8 The membranes 14 are configured to move in response to a fluid flow 5 through the duct 2

9 and or a compression wave 6 traversing the duct 2. 0 1 The one or more membranes 14 are orientated substantially perpendicular to the central2 axis 7 of the duct 2. The one or more membranes 14 are orientated to extend across at3 least a portion of the duct’s 2 cross-sectional area. In the embodiment of Figure 1 , the4 membrane 14a fully extend across duct’s cross-sectional area. 5 6 Figures 2a depicts a cross-section of the energy harvesting device 1a in the y-z plane and7 specifically shows the cross-sectional shape of the duct 2. As can be seen, each 8 membrane 14a comprises one or more members 15, for example, Figure 2a depicts five9 longitudinal members 15 extending in the z direction across the full extent of the duct’s0 cross-sectional. 1 2 The dimensions, material composition and or relative spacing of the members 15 of each3 membrane 14 are configured such that the members 15 move in response a fluid flow 54 through the duct 2 and or a compression wave 6 traversing the duct 2. As such, the5 membrane 14a may be considered a mesh or fabric formed of the members 15. Whilst the6 members 15 of Figure 2a form a regular uniform structure, it will be appreciated that the7 members 15 may form any uniform or non-uniform structure. The membrane 14a could8 also be considered a penetrable barrier obstructing the duct 2. 9 0 Figure 2b depicts an alternative membrane 14b which extends across a portion of the1 duct’s cross-sectional area. More specifically, the members 15 depicted in Figure 2b are2 dimensioned to extend across a portion of the duct’s cross-sectional area. 3 1 In operation, a fluid flow 5 and or compression wave 6 enters the duct 2, through the inlet

2 opening 3, actuating the membrane 14 whilst traversing the duct 2 thereby generating

3 movement, specifically vibrations.

4

5 Vibrational Lens and Energy Conversion Means

6

7 The energy harvesting device 1a further comprises one or more vibrational lenses 16 and

8 an energy conversion means 17 as can be seen in Figures 1 and 3.

9 0 The one or more vibrational lenses 16 connect the one or more membranes 14 to the1 energy conversion means 17. Furthermore, the one or more vibrational lenses 16 capture,2 transmit, converge and or focus movement, specifically vibrations, from the one or more3 membranes 14 to the energy conversion means 17. The vibrational lens 16 has a dual4 purpose as it could also be a means for mounting each of the membranes 14 within the5 duct 2. The energy conversion means 17 is employed to convert the movement of the one6 or more membranes 14 into electricity. 7 8 The vibrational lens 16 may be of a type as described in the applicant’s co-pending UK9 patent number GB2586067 and UK patent application number GB2008912.4. As depicted0 in Figures 3, the vibrational lens 16 comprises at least two focusing members 18. Each of1 the at least two focusing members 18 having a first end 19 for attachment to a vibrational2 source, in this case the membranes 14, and a second end 20 located at which is the3 energy conversion means 17. The at least two focusing members 18 are arranged such4 that the separation between the focusing members 18 decreases from the first ends 195 towards the second ends 20. 6 7 The one or more membranes 14 are designed to oscillate and vibrate at a relatively low8 frequency between 10 to 50 Hz and a relatively high amplitude equating to a displacement9 of the second end 20 of the focusing members 18 between 10 and 25 mm. Alternatively,0 the membranes may vibrate at a medium frequency over 50 Hz with a similar relatively1 high amplitude (10 to 25 mm). 2 3 The energy conversion means 17 is located at the second end 20 of the vibrational lens4 16. As depicted in Figure 4a the energy conversion means 17 takes the form of a magnet5 21 attached to the second end 20 of the focusing members 18 and a coil 22 is located 1 about the magnet 21 . The energy conversion means 17 operates on the principle of

2 magnetic induction in that the movement of the magnet 21 relative to the coil 22 creates a

3 changing magnetic flux inducing a current in the coil 22.

4

5 As an additional or alternative feature and as can be seen in Figure 4b, the energy

6 conversion means 17 may take the form of piezoelectric crystals 23 located between the

7 second ends 20 of the focusing members 18. In operation, the second ends 20 of the

8 focusing members 18 mechanically actuate the piezoelectric crystals 23 which generates

9 electricity. More specifically, the second ends 20 of the focusing members 18 compress0 and decompress the piezoelectric crystals 23. It will be appreciated the energy conversion1 means 17 may comprise both a magnet 21 and coil 22 arrangement and piezoelectric2 crystals 23. 3 4 The one or more vibrational lenses 16 and energy conversion means 17 are located within5 the energy harvesting device 1 a but not within the duct 2. The duct 2 comprises a duct6 wall 24. The focusing members 18 of the one or more vibrational lenses 16 pass through7 the duct wall 24 to connect to the one or more membranes 14. As an example, the8 focusing members 18 pass through the duct wall 24 by means of a fluid tight bearing 259 which transmits the motion of the one or more membranes 14. As such, the one or more0 vibrational lenses 16 and energy conversion means 17 are not exposed to any fluid, such1 as sea water, within the duct 2. 2 3 Energy Harvesting Device in Use 4 5 In operation, the energy harvesting device 1 a of Figure 1 is, for example, located at an6 interface between sea 26 and land 27. The inlet opening 3 on the first surface 8 is7 orientated towards the sea 26. The energy harvesting device 1a is positioned such that8 the sea level 28 is at the same height or above the inlet opening 3 of the energy harvesting9 device 1a. For example, the sea level 28 is depicted in Figure 1 as above inlet opening 3. 0 As such, the duct 2 is partially flooded with sea water. 1 2 Sea waves result in a fluid flow 5 in the form of a sea water flow 29 and or compression3 waves 6 within the sea water, entering the inlet opening 3 and traversing the duct 2. The4 one or more membranes 14 depicted in Figure 1 are located in the within the duct 2 below5 the sea level 28, in other words within the flooded region of the duct 2. As such, the sea 1 water flow 29 and or compression wave 6 actuates the one or more membranes 14. More

2 specifically, in a preferred embodiment the water flow 29 and or compression wave 6 may

3 vibrationally actuate and or percussively actuate and or ballistically actuate and or

4 collisionally actuate the one or more membranes 14. Additionally, the water flow 29 and or

5 compression wave 6 may actuate the one or more membranes 14 without generating lift.

6 This movement is transmitted to the energy conversion means 17 by the one or more

7 vibrational lenses 16. The energy conversion means 17 converts this movement into

8 electricity.

9 0 After interacting with the one or more membranes 14, the sea water flow 29 drains out of1 the duct 2 through the passageway 11 and exits the energy harvesting device 1 a through2 the second outlet opening 12. Furthermore, an air flow 30 or a compression wave 6 within3 air created within the energy harvesting device 1a due to the displacement of the air by the4 sea water flow 29 and or the compression wave 6 within the sea water, can vent out of the5 energy harvesting device 1a through the first outlet opening 4, located above the sea level6 28. 7 8 The described operation will repeat and continually generate electricity as sea waves will9 continuously enter the energy harvesting device 1a. 0 1 Whilst the inclusion of a vibrational lens 16 has numerous advantages, it will be 2 appreciated by a person skilled in the art that the energy harvesting device 1 a could be3 implemented with an alternative connection means between the one or more membranes4 14 and the energy conversion means 17. Furthermore, the one or more membranes 145 may be directly connected to the energy conversion means 17 without the requirement for6 a vibrational lens 16. 7 8 Energy Harvesting System 9 0 Figure 5 shows an energy harvesting system 31 comprising an array of the energy1 harvesting devices 1 a stacked side-by-side and upon each other. As such, the energy2 harvesting system 1 a may take the form of a sea wall and the sea wall acts as a 3 distributed electricity generation system. 4 5 Alternative Energy Harvesting Devices 1

2 Figure 6 depicts an alternative energy harvesting device 1 b which may comprise the same

3 preferable and optional features as the energy harvesting device 1 a depicted in Figures 1

4 to 5. In contrast to the energy harvesting device 1 a of Figure 1 , the one or more

5 membranes 14 depicted in Figure 6 are located within the duct, above the sea level 28, in

6 other words within the non-flooded region of the duct 2. As such, the one or more

7 membranes 14 are actuated by an air flow 30 or a compression wave 6 within the air

8 generated by the sea wave.

9 0 Figure 7 depicts an alternative energy harvesting device 1c which may comprise the same1 preferable and optional features as the energy harvesting devices 1 a, 1 b depicted in2 Figures 1 to 6. The energy harvesting device 1 c of Figure 7 combines the energy 3 harvesting devices 1 a, 1 b of Figures 1 to 6. The energy harvesting device 1c of Figure 74 comprises two sets of one or more membranes 14. A first set of one or more membranes5 14 is located within the duct, below the sea level 28, and a second set of one or more6 membranes 14 located within the duct, below the sea level 28. It will be appreciated there7 will be multiple vibrational lenses 16 and energy conversion means 17 to accommodate8 the two sets of one or more membranes. It will be appreciated they may be a plurality of9 sets of one or more membranes 14. 0 1 Figure 8 depicts an alternative energy harvesting device 1d which may comprise the same2 preferable and optional features as the energy harvesting devices 1 a, 1 b, 1 c depicted in3 Figures 1 to 7. The energy harvesting device 1 d of Figure 8 comprises three ducts 2, each4 duct 2 extending between the inlet opening 3 on the first surface 8 to the first outlet5 opening 4 on the second surface 9. Furthermore, each duct 2 comprises at least one set6 of one or more membranes 14, one or more vibrational lenses 16 and energy conversion7 means 17. 8 9 Figure 9 depicts an alternative energy harvesting device 1 e which may comprise the same0 preferable and optional features as the energy harvesting devices 1 a, 1 b, 1 c, 1d depicted1 in Figures 1 to 8. The energy harvesting device 1 e of Figure 9 comprises a plurality of2 ducts 2 extending between numerous surfaces of the energy harvesting device 1 e, not just3 the first and second surfaces 8, 9. Each opening 3, 4 may be considered an inlet 3 or an4 first outlet opening 4 depending on the orientation of the energy harvesting device 1 e and5 the direction of incident fluid flows 5 and or compression waves 6. Advantageously, the 1 energy harvesting device 1 e of Figure 9 can interact with fluid flows 5 and or compression

2 waves 6 incident on the energy harvesting device 1 e from multiple directions.

3

4 Figures 10 and 1 1 depict an alternative energy harvesting device 1f which may comprise

5 the same preferable and optional features as the energy harvesting devices 1 a, 1 b, 1c, 1 d,

6 1 e depicted in Figures 1 to 9.

7

8 In contrast to previous embodiments, the one or more membranes 14 of the energy

9 harvesting device 1f of Figure 10 are orientated substantially parallel to the central axis 70 of the duct 2. The arrangement of the membrane 14 can clearly be seen in Figure 11 .1 Each membrane 14 is located within the duct 2 and mounted on a support structure 32.2 The support structure is 32 is attached to the duct wall 24. The focusing members 18 of3 the one or more vibrational lenses 16 extend through the duct wall 24 and attach to the4 membrane 14. Each focusing member 18 attaches to different regions of the membrane5 14. It will be appreciated the focusing members 18 may attach to both the membrane 146 directly and the support structure 32. 7 8 In operation, a fluid flow 5 and or compression wave 6 traversing the duct 2 in the y9 direction will travel parallel to the membrane 14. The fluid flow 5 and or compression wave0 6 will induce movement in the membrane 14 due to a pressure imbalance and or turbulent1 perturbation in the region of the membrane 14. As with previous embodiments, the2 movement of the membrane 14 is transmitted to the energy conversion means 17 by the3 vibrational lens 16 and the energy conversion means 17 converts this movement into4 electricity. In this embodiment, the membrane 14 may be considered an impenetrable5 barrier. 6 7 It can be seen from Figure 10 that membranes 14 are located through the extent of the8 duct 2, in the flooded and non-flooded regions of the duct 2, above and below sea level 28. 9 As such, it will be appreciated that the membranes 14 may be actuated by both a sea0 water flow 29, an air flow 30, a compression wave 6 in sea water and or a compression1 wave 6 in air. 2 3 Figures 12 depicts an alternative energy harvesting device 1 g which may comprise the4 same preferable and optional features as the energy harvesting devices 1 a, 1 b, 1 c, 1 d, 1 e,5 1f depicted in Figures 1 to 11 . Figure 12 depicts an alternative arrangement of the 1 membrane 14. In comparison to the embodiment of Figure 10 and 1 1 , mounted on the

2 support structure 32 may be multiple membranes 14 all orientated substantially parallel to

3 the central axis 7 of the duct 2 and all connected to the energy conversion means 17 by

4 the vibrational lens 16. In this embodiment the vibration lens 16 comprises a plurality of

5 focusing members 18 dividing to attach to numerous regions of every membrane 14.

6

7 Figures 13 depicts an alternative energy harvesting device 1 h which may comprise the

8 same preferable and optional features as the energy harvesting devices 1 a, 1 b, 1 c, 1 d, 1 e,

9 1 f, 1 g depicted in Figures 1 to 12. Figure 13 depicts a further alternative arrangement of0 the membrane 14. Similar to Figure 10 and 11 , each member is orientated substantially1 parallel to the central axis 7 and mounted on the support structure 32. However, the2 embodiment further comprises one or more sticks 33 each pivotally mounted to a mast 343 extending orthogonally from the membrane 14 towards the central axis 7 of the duct 2. In4 operation, a fluid flow 5 and or compression wave 6 pivots the sticks 33 such that the5 sticks 33 strike the membrane 14 enhancing the movement of the membrane 14. As such,6 the sticks 33 advantageously enhance the amount of electricity generated by the energy7 harvesting device 1 h. 8 9 Figures 14 depicts an alternative energy harvesting device 1 i which may comprise the0 same preferable and optional features as the energy harvesting devices 1 a, 1 b, 1 c, 1 d, 1 e,1 lf, 1 g, 1 h depicted in Figures 1 to 13. Figure 14 depicts membranes 14 mounted on2 multiple surfaces of the support structure 32. Advantageously, this arrangement increases3 the energy captured from the fluid flow 5 and or compression waves 6 thereby increasing4 the efficiency of the energy harvesting device 1 i. 5 6 Figure 15 depicts an alternative energy harvesting device 1j which may comprise the same7 preferable and optional features as the energy harvesting devices 1 a, 1 b, 1 c, 1 d, 1 e, 1 f,8 lg, 1 h, 1 i depicted in Figures 1 to 14. Figure 15 depicts an energy harvesting device 1j9 suitable for being fully submerged in the sea 26. As such, the passageway 1 1 and second0 outlet opening 12 which acted as a drain in previous embodiments is not required. In this1 embodiment, the fluid flow 5 actuating the membranes 14 may be a tidal flow. The tidal2 flow enters the duct 2 by the inlet opening 3, traverses the duct 2 and exits by the first3 outlet opening 4. Similarly, Figure 15 is also suitable for use on land 27 where the fluid4 flow 5 actuating the membranes 14 may be wind. 5 1 Figures 16 and 17 depict an alternative energy harvesting device 1 k which may comprise

2 the same preferable and optional features as the energy harvesting devices 1 a, 1 b, 1c, 1 d,

3 1 e, 1 f, 1g, 1 h, 1 i, 1j depicted in Figures 1 to 15.

4

5 In contrast to the energy harvesting devices 1 a, 1 b, 1 c, 1 d, 1 e, 1f, 1g, 1 h, 1 i, 1j of Figure 1

6 to 15, the membranes 14 of the energy harvesting device 1 k of Figures 16 and 17 are

7 located on one or more external surfaces 35 of the energy harvesting device 1 k. In other

8 words, the energy harvesting devices 1 k of Figures 16 and 17 do not comprise a duct.

9 The membranes 14 are located substantially parallel to the external surface 35 and0 configured to be actuated by a fluid flow 5 incident upon and or traversing parallel to the1 external surface 35. The membranes 14 may be mounted on a support structure 32, as2 previously described with reference to Figure 10 and 1 1 . 3 4 As with previous embodiments, one or more vibrational lenses 16 connect the membranes5 14 to one or more energy conversion means 17. The one or more vibrational lenses 166 pass through the external surface 35 to connect with the one or more energy conversion7 means 17 located within the energy harvesting devices 1 k. The one or more vibrational8 lenses 16 capture, transmit, converge and or focus movement, specifically vibrations, from9 the one or more membranes 14 to the energy conversion means 17. It will be appreciated0 that the membranes 14 may be located on multiple external surfaces 35 as depicted by1 Figure 17. 2 3 Method of Manufacturing an Energy Harvesting Device 4 5 Figure 18 shows a flow chart for a method of manufacturing an energy harvesting device6 1. The method comprises: providing one or more membranes (S1001 ); providing an7 energy conversion means employed to convert movement of the one or more membranes8 into electricity (S1002); and providing one or more vibrational lenses connecting the one or9 more membranes to the energy conversion means (S1003). 0 1 In addition, the method of manufacturing may optionally also comprise providing a duct2 and locating the one or more membranes within the duct. 3 4 In addition, the method of manufacturing may optionally comprise characterising the fluid5 flow 5. For example, this may include characterising: the medium such as air or water, the 1 mean fluid flow speed, fluid flow speed distribution, turbulence, fluid flow shear profile,

2 distribution of fluid flow direction and long-term temporal fluid flow variations. Similarly, the

3 method of manufacturing may optionally comprise characterising the compression wave 6.

4 For example, this may include characterising: the frequency, amplitude, wavelength and

5 speed.

6

7 As a further addition, the method of manufacturing may option comprises utilising the

8 characteristics of the fluid flow 5 and or compression wave 6 to determine the optimum

9 parameters of the energy harvesting device 1 . For example, this optimisation process may0 include determining: the dimensions of the energy harvesting device 1 ; the dimension and1 shape of the duct(s) 2; the dimension and shape of the passageway 11 and if the 2 passageway 11 is required; the number, dimension, shape, material composition, 3 structure, orientation and arrangement of the one or more membranes 14; and the 4 dimension, shape, material composition, orientation and arrangement of the one or more5 vibrational lenses. Optimising the vibrational lens 16 by matching average movement6 (vibrational) resonant frequency across the operational range of the one or more 7 membranes 14. 8 9 The energy harvesting device 1 has numerous advantages. The energy harvesting device0 1 harvests energy from an under exploited source, namely sea waves. Instead of 1 dissipating this the energy of sea waves through noise and movement, the devices2 depicted in Figure 1 to 17 convert this kinetic energy into vibrational energy which is then3 captured and converted into electrical energy. 4 5 A further advantage is that the energy harvesting device 1 can be compact, it is modular6 and it can form part of a larger system 31 . The energy harvesting device 1 and systems7 31 can be discretely integrated into the environment in the form of seawalls at the interface8 between land and sea. The energy harvesting device 1 can enhance the functionality of a9 seawall by providing another mechanism to redirect the energy of the sea waves but also0 provide a source of renewal energy. Furthermore, the energy harvesting device 1 may1 also be suitable for use in other locations such as when fully submerged at sea as a tidal2 device or on land as a wind device. 3 4 An energy harvesting device is disclosed. The energy harvesting device comprises one or5 more membranes and an energy conversion means employed to convert movement of the 1 one or more membranes into electricity. The energy harvesting device also comprises one

2 or more vibrational lenses connecting the one or more membranes to the energy

3 conversion means. The energy harvesting device provides an alternative device for

4 generating renewable energy with numerous advantages. The device harvests vibrational

5 energy, can be optimised to operate over a broad range of fluid flow parameters, has

6 minimal negative environmental impact and is suitable for numerous locations and

7 applications.

8

9 Throughout the specification, unless the context demands otherwise, the terms “comprise”0 or “include”, or variations such as “comprises” or “comprising”, “includes” or “including” will1 be understood to imply the inclusion of a stated integer or group of integers, but not the2 exclusion of any other integer or group of integers. Furthermore, unless the context clearly3 demands otherwise, the term “or” will be interpreted as being inclusive not exclusive.4 5 The foregoing description of the invention has been presented for purposes of illustration6 and description and is not intended to be exhaustive or to limit the invention to the precise7 form disclosed. The described embodiments were chosen and described in order to best8 explain the principles of the invention and its practical application to thereby enable others9 skilled in the art to best utilise the invention in various embodiments and with various0 modifications as are suited to the particular use contemplated. Therefore, further 1 modifications or improvements may be incorporated without departing from the scope of2 the invention as defined by the appended claims.