GB2604639A

GB2604639A - Wind energy harvesting device, system and method of manufacture

Info

Publication number: GB2604639A
Application number: GB2103390.7A
Authority: GB
Inventors: Velayutham Karthikeyan
Original assignee: Katrick Technologies Ltd
Current assignee: Katrick Technologies Ltd
Priority date: 2021-03-11
Filing date: 2021-03-11
Publication date: 2022-09-14
Also published as: GB2604674A; GB202103390D0; GB202113126D0; GB2604674B

Abstract

A wind energy harvesting device comprises a duct 8a with an inlet opening 10 and an outlet opening 11. One or more aerofoils 13 are located within the duct, a leading edge of the aerofoil is orientated towards the inlet opening. A vibrational lens 38 transmits, converges, and focuses vibrations from the aerofoil towards the energy conversion means 39 where it is converted into electricity. The vibrational lens may comprise at least two focusing members 40 arranged such that the separation between the focusing member decreases from the first ends 41 towards the second ends 42. Preferably the energy conversion means takes the form of piezoelectric crystals.

Description

1 Wind Enemy Harvesting Device, System and Method of Manufacture 3 The present invention relates to a wind energy harvesting device, system and method of 4 manufacture. In particular, the wind energy harvesting device is suitable for producing renewable energy.

7 Background to the Invention

9 A conventional horizontal-axis wind turbine known in the art typically comprises three blades. The wind turbine converts the kinetic energy of the wind into mechanical motion 11 according to the principle of aerodynamic lift. In operation, the blades rotate and drive a 12 generator which converts the mechanical motion into electricity.

14 Whilst wind turbines are widely used in the energy industry to offer a source of renewable energy, there are numerous disadvantages. Wind turbines can only operate within a 16 narrow wind speed window. For example, if the wind speed is too high there is a risk of 17 damaging the wind turbines. Conversely if the wind speed is too low, then there may not 18 be enough aerodynamic lift to rotate the blades.

1 Commercial wind farms typically comprise large wind turbines which can be over 100 m 2 tall. Whilst large wind turbines are more efficient than smaller scale micro wind turbines, 3 the large wind turbines typically dominate the surrounding landscape and have a negative 4 aesthetic impact on the environment. There are further negative environmental consequences as wind turbines can affect the surrounding wildlife. For example, the 6 blades of the wind turbines can kill birds.

8 In addition, such large wind turbines are not suitable to be located in urban landscapes, by 9 motorways and especially not near airports as they tend to produce a significant turbulent flow in the wake of the blades.

12 Summary of the Invention

14 It is an object of an aspect of the present invention to provide a wind energy harvesting device that obviates or at least mitigates one or more of the aforesaid disadvantages of the 16 energy harvesting devices known in the art.

18 According to a first aspect of the present invention there is provided a wind energy 19 harvesting device comprising: a duct with an inlet opening and an outlet opening; 21 one or more aerofoils located within the duct wherein a leading edge of the one or more 22 aerofoils is orientated towards the inlet opening; and 23 a generator employed to convert movement of the one or more aerofoils into electricity.

Preferably, the inlet opening is located on a first surface of the wind energy harvesting 26 device and the outlet opening is located on a second surface of the wind energy 27 harvesting device.

29 Preferably, the second surface substantially opposes the first surface. Alternatively, the second surface is substantially tangential to the first surface.

32 Alternatively, the inlet opening is located in a first region of a first surface and the outlet 33 opening is located in a second region of the first surface.

1 Most preferably, the one or more aerofoils comprises a thickness variation in a span 2 direction of the one or more aerofoils. The one or more aerofoils may comprise both 3 positive and negative cambered cross sections. The one or more aerofoils creates 4 counter interacting lift and drag forces inducing vibrations, more specifically, flutter vibrations.

7 Preferably, the one or more aerofoils comprises a thickness variation in a chord direction 8 of the one or more aerofoils.

Optionally, the one or more aerofoils comprises one or more weights. The one or more 11 weights are uniformly or non-uniformly distributed within an internal structure of the one or 12 more aerofoils.

14 Preferably, the wind energy harvesting device further comprises a generator housing. The generator housing may comprise a cone-like portion protruding from the first surface.

17 Optionally, the cone-like portion comprises one or more fins. The fins may comprise 18 discontinuous vertices. The fins induce turbulent air flow.

Optionally, the wind energy harvesting device further comprises one or more flaps. The 21 one or more flaps are located at the inlet opening of the duct and or at a trailing edge of 22 the aerofoil. The flaps induce turbulent air flow.

24 Optionally, the wind energy harvesting device further comprises a mesh across the inlet opening and or outlet opening. The mesh induces turbulent air flow and or acts as a 26 barrier protecting, for example, the aerofoil.

28 Optionally, the wind energy harvesting device further comprises flow restrictors. The flow 29 restrictors are located within the duct. The flow restrictors narrow or widen the duct. The flow restrictors induce turbulent air flow.

32 Most preferably, the generator comprises one or more vibrational lens and one or more 33 energy conversion means.

1 Preferably, the vibrational lens comprising at least two focusing members, each of the at 2 least two focusing members having a first end for attachment to an aerofoil and a second 3 end, wherein the at least two focusing members are arranged such that the separation 4 between the focusing members decreases from the first ends towards the second ends.

6 Optionally, the vibrational lens comprises a plurality of focusing members wherein two or 7 more aerofoils may be attached the vibrational lens.

9 Preferably, the first ends of the at least two focusing members are attached to the internal structure the aerofoil. Alternatively, the first ends of the at least two focusing members are 11 attached to a surface of the aerofoil, more specifically a first side of the aerofoil.

13 Preferably, the at least two focusing members merge towards the second end of the 14 vibrational lens. The at least two focusing members may merge before or after passing through the generator housing.

17 Preferably, the at least two focusing members pass through the generator housing by 18 means of a bearing.

Most preferably, the energy conversion means is located at the second end of the 21 vibrational lens.

23 Preferably, the energy conversion means is a magnet and coil. Optionally, the energy 24 conversion means further comprises a rotor and an elastic coil connector.

26 Alternatively, the energy conversion means is a piezoelectric crystal.

27 Most preferably, the wind energy harvesting device further comprises two or more ducts 28 each of the two or more ducts having an inlet opening and an outlet opening. Preferably 29 each of the two or more ducts comprise one or more aerofoils located within the duct wherein a leading edge of the one or more aerofoils is orientated towards the inlet 31 opening. Optionally, the wind energy harvesting device comprises a maximum of eighteen 32 ducts.

34 Preferably, the two or more ducts are located about a generator housing.

1 Optionally, the two or more ducts form one or more branch members for the generator 2 housing.

4 Optionally, the wind energy harvesting device further comprises a lens. The lens is suitable for focusing solar radiation and inducing convection air flow.

7 Optionally, the wind energy harvesting device further comprises a layer of noise insulation.

9 According to a second aspect of the present invention there is provided a wind energy harvesting system comprising two or more wind energy harvesting devices in accordance 11 with the first aspect of the present invention.

13 Preferably, the two or more wind energy harvesting devices are stacked side-by-side and 14 or upon each other.

16 Embodiments of the second aspect of the invention may comprise features to implement 17 the preferred or optional features of the first aspect of the invention or vice versa.

19 According to a third aspect of the present invention there is provided a method of manufacturing a wind energy harvesting device comprising: 21 providing a duct with an inlet opening and an outlet opening; 22 providing one or more aerofoils located within the duct wherein a leading edge of the 23 one or more aerofoils is orientated towards the inlet opening; and 24 providing a generator to convert movement of the one or more aerofoils into electricity.

27 Most preferably, the method of manufacturing a wind energy harvesting device further 28 comprises characterising an air flow.

Preferably, characterising an air flow comprises characterising the mean air flow speed, air 31 flow speed distribution, turbulence, air flow shear profile, distribution of air flow direction 32 and long-term temporal air flow variations.

1 Most preferably, the method of manufacturing a wind energy harvesting device further 2 comprises determining the optimum parameters of the wind energy harvesting device for 3 use with the air flow.

Preferably, determining the optimum parameters of the wind energy harvesting device 6 comprises determining: the dimensions of the wind energy harvesting device; the 7 dimension and shape of the duct, the shape and structure of the aerofoil; the dimension, 8 shape, material composition, orientation and arrangement of the vibrational lens 38; the 9 relative positioning of two or more aerofoils within the duct; the arrangement and configuration of fins, flaps, mesh and flow restrictors; and the arrangement and 11 configuration of the generator.

13 Embodiments of the third aspect of the invention may comprise features to implement the 14 preferred or optional features of the first and or second aspects of the invention or vice versa.

17 According to a fourth aspect of the present invention there is provided an aerofoil 18 comprising a thickness variation in a chord and or span direction.

Preferably, the aerofoil comprises both positive and negative cambered cross sections.

22 The aerofoil creates counter interacting lift and drag forces inducing vibrations, more 23 specifically, flutter vibrations.

Embodiments of the fourth aspect of the invention may comprise features to implement the 26 preferred or optional features of the first, second and or third aspects of the invention or 27 vice versa.

29 Brief Description of Drawings

31 There will now be described, by way of example only, various embodiments of the 32 invention with reference to the drawings, of which: 34 Figure 1 presents a perspective view of a wind energy harvesting device in accordance with an embodiment of the present invention; 2 Figure 2 presents a front view of the wind energy harvesting device of Figure 1; 4 Figures 3 presents a schematic cross-sectional view of the energy harvesting device of Figure 1; 7 Figure 4 presents a perspective view of a duct of an alternative embodiment of the energy 8 harvesting device of Figure 1; Figure 5 presents a perspective view of an aerofoil of the energy harvesting device of 11 Figure 1; 13 Figure 6 presents a perspective view of an alternative embodiment of the aerofoil of Figure 14 5; 16 Figure 7 presents a schematic view of (a) a positive cambered aerofoil cross-section and 17 (b) a negative cambers aerofoil cross-section of the aerofoil of Figure 6; 19 Figure 8 presents a schematic cross-section view of an alternative embodiment of the aerofoil of Figure 5; 22 Figure 9 presents a perspective view of a further alternative embodiment of the aerofoil of 23 Figure 5; Figure 10 presents a schematic cross-sectional view of a generator of the wind energy 26 harvesting device of Figure 1; 28 Figure 11 presents a perspective view of a wind energy harvesting system comprising the 29 wind energy harvesting device of Figure 1; 31 Figures 12 presents a perspective view of an alternative embodiment of the wind energy 32 harvesting device of Figure 1; 34 Figure 13 presents a perspective view of a further alternative embodiment of the wind energy harvesting device of Figure 1; 2 Figure 14 presents a perspective view of a yet another further alternative embodiment of 3 the wind energy harvesting device of Figure 1; Figures 15 presents a perspective views of a further alternative embodiment of the wind 6 energy harvesting device of Figure 1; 8 Figure 16 presents a perspective view of a further alternative embodiment of the wind 9 energy harvesting device of Figure 1; and 11 Figure 17 presents a flow chart of the method of manufacturing the wind energy harvesting 12 device of Figure 1.

14 In the description which follows, like parts are marked throughout the specification and drawings with the same reference numerals. The drawings are not necessarily to scale 16 and the proportions of certain parts have been exaggerated to better illustrate details and 17 features of embodiments of the invention.

19 Detailed Description of the Preferred Embodiments 21 An explanation of the present invention will now be described with reference to Figures 1 22 to 17.

24 Wind Energy Harvesting Device 26 Figures 1 and 2 depict a substantially cuboid wind energy harvesting device la comprising 27 a first surface 2a and an opposing second surface 3a. The first and second surfaces 2a, 28 3a are both perpendicular to and centred about a central axis 4.

Generator Housing 32 The wind energy harvesting device la further comprises a generator housing 5a centred 33 about the central axis 4. The generator housing 5a comprises an internal portion 6 and a 34 cone-like portion 7, as can clearly be seen in Figure 3. The internal portion 6 of the generator housing 5 extends between the first and second surfaces 2a, 3a and has a 1 substantially circular cross-sectional shape. It will be appreciated the internal portion 6 of 2 the generator housing 5 may have any suitable cross-sectional shape which can vary 3 between the first and second surfaces 2a, 3a. The cone-like portion 7 of the generator 4 housing 5a is a continuation of the internal portion 6 that protrudes from the first surface 2a and tapers towards the central axis 4.

7 Ducts 9 The wind energy harvesting device la further comprises ducts 8a located circumferentially about the generator housing 5a, as clearly shown by Figures 1 and 2. The ducts 8a take 11 the form of passageways between the first and second surfaces 2a, 3a suitable for 12 channelling air flow 9 through the wind energy harvesting device 1 a. The cone-like portion 13 7 of the generator housing 5a diverts the air flow 9 towards the ducts 8a. It has been 14 found preferable for efficient operation for the wind energy harvesting device la as depicted in Figure 1 and 2 to comprise no more than eighteen ducts 8a located about the 16 generator housing 5a.

18 Each duct 8a comprises an inlet opening 10 on the first surface 2a and a corresponding 19 outlet opening 11 on the second surface 3a. As can be seen in Figures 1 and 2, the ducts 8 comprise a substantially elliptical cross-sectional shape. The ducts 8a are orientated 21 such that the semi-major axis of the elliptical cross-sectional shape extends radially from 22 the central axis 4. It will be appreciated the ducts 8a may have any suitable cross- 23 sectional shape.

As shown in Figures 1 and 2, each duct 8a has a different relative size according to the 26 location of the duct 8a on the first surface 2a. As an alternative, it will be appreciated each 27 duct 8a may all be uniform in size.

29 Figures 2 and 3 show that the cross-sectional shape of the ducts 8a changes in the direction of the central axis 4. In other words, the cross-sectional shape changes between 31 the first and second surfaces 2a, 3a. This variation of the cross-sectional shape of the 32 ducts 8a can be configured to modify the velocity of the air flow 9 through the wind energy 33 harvesting device la. As an alternative, the ducts 8a may comprise a uniform cross- 34 sectional shape.

1 Figures 1 and 3 show that the ducts 8a comprise optional external portions 12 protruding 2 from the second surface 3. The external portions 12 are configured to divert the air flow 9 3 exiting the wind energy harvesting device la from the outlet openings 11.

Aerofoils 7 The wind energy harvesting device 1 further comprises one or more aerofoils 13, located 8 within each duct 8a, as shown in Figures 3 and 4.

Figure 5 depicts an aerofoil 13 and defines several terms used to describe the shape of 11 the aerofoil 13. The aerofoil 13 comprises a leading edge 14 and a trailing edge 15. The 12 leading edge 14, or foremost edge, is the first aerofoil surface to meet an incident air flow 13 9. As such, the leading edge 14 separates the incident air flow 9. The trailing edge 15, or 14 rearmost edge, is where the air flow 9 separated by the leading edge 14 meets.

16 The aerofoil 13 also comprises a chord 16 and span 17. The chord 16 is the distance 17 between the leading and trailing edges 14, 15. Whereas the span 17 is the distance 18 between a first side 18 and a second side 19 of the aerofoil 13. In addition, a chord line 20 19 is defined as an imaginary straight line connecting the leading and trailing edge 14, 15.

21 The aerofoil 13 further comprises an upper surface 21 and a lower surface 22. The 22 relative curvature of the upper and lower surfaces 19, 21 is parameterised by a camber 23 line 23 which is a line equidistant between the upper and lower surfaces 19, 21 extending 24 across the chord direction of the aerofoil 13. The aerofoil 13 comprises a uniform cross section across the span 17.

27 Figure 3 depicts the aerofoil 13 mounted within a duct 8a. The aerofoil 13 is orientated 28 such that the leading edge 14 is located towards the inlet opening 10 and the trailing edge 29 15 is located towards the outlet opening 11. In other words, the chord direction of the aerofoil 13 is substantially parallel to the central axis 4.

32 In operation, an air flow enters the duct 13 through the inlet opening 10, flows past the 33 aerofoil 13 inducing aerodynamic forces and then exits the duct 13 through the outlet 34 opening 11. The aerofoil 13 exhibits vibrations and or specifically flutter vibrations, and it 1 is the kinetic energy from these vibrations that the wind energy harvesting device la 2 captures, focuses, and converts into electrical energy.

4 When aerodynamic forces deflect an aerofoil 13 a restoring force acts to return the aerofoil 13 to its original shape due to the elasticity of the aerofoil 13 structure. Flutter is a 6 dynamic instability caused by positive feedback between the aerodynamic forces and the 7 restoring force of the aerofoil 13. Whilst aerofoils 13 known in the art are typically 8 designed to avoid flutter, these vibrations are desirable in the wind energy harvesting 9 device la as it is mechanical vibrational energy the present invention converts into useful electrical energy. ii

12 Whilst the aerofoil 13 of Figure 5 can exhibit flutter vibrations, it is possible and preferable 13 to enhance these flutter vibrations by: 14 a) modifying the shape and structure of the aerofoil 13 to induce and or amplify counter interacting lift; and or 16 b) adjusting the air flow 9 to, for example, induce a turbulent air flow 24.

18 (a) Modified Aerofoil Figure 6 depicts a modified aerofoil 25a comprising a thickness variation in the span 21 direction. The modified aerofoil 25a comprises both positive and negative cambered cross 22 sections 26, 27. A positive cambered cross section 26 results in a lift force 28 and is 23 defined by the camber line 23 being located between the upper surface 21 and chord line 24 20, as depicted in Figure 7a. A negative cambered cross section 27 results in a drag force 29 and is defined by the camber line 23 being located between the lower surface 22 and 26 the chord line 20, as can be seen by Figure 7b. The modified aerofoil 25a exhibits counter 27 interacting lift and drag forces 28, 29 inducing vibrations and or specifically flutter 28 vibrations. The modified aerofoil 25a of Figure 6 exhibits vibrations about an axis parallel 29 to the chord direction.

31 As an additional or alternative feature, the modified aerofoil 25a may further comprise 32 weights 30 to induce and or amplify the vibrations. The modified aerofoil 25a is hollow and 33 comprises an internal structure 31. The weights 30 depicted in Figure 6 are non-uniformly 34 distributed within the internal structure 31 of the aerofoil 25a across the chord and span directions.

2 Figure 8 depicts an alternative modified aerofoil 25b comprising a thickness variation in the 3 chord direction. This results in lift and drag forces 28, 29 across the chord direction of the 4 aerofoil 25b inducing vibrations about an axis parallel to the span direction.

6 Figure 9 depicts a further alternative modified aerofoil 25c comprising thickness variations 7 in both the span and chord direction resulting in a combination of vibrations about axes 8 parallel to the chord and span directions.

(b) Adiustinn air flow ii 12 As an additional or alternative feature, the wind energy harvesting device 1 comprises fins 13 32 as depicted in Figure 3 protruding from the cone-like portion 7 of the generator housing 14 5a. The fins 32 comprise discontinuous vertices 33 disrupting the smooth laminar flow of the incident airflow 9 and creating turbulent air flow 24.

17 As a further additional or alternative feature, the wind energy harvesting device la 18 comprises flaps 34. As depicted in Figure 3, the flaps 34 are located at the inlet opening 19 10 of the duct 8a and or, as depicted in Figure 4, the flaps 34 are located at the trailing edge of the aerofoil 13. The flaps 34 pivot to divert and disrupt the air flow 9 creating 21 turbulent air flow 24.

23 As another additional or alternative feature, the wind energy harvesting device la 24 comprises a mesh 35 across the inlet opening 10 of the duct 8a as depicted in Figure 4.

The mesh 35 is uniform yet it will be appreciated the mesh 35 could instead by non- 26 uniform. The air flow 9 entering the inlet opening 10 of the duct 8a passes through the 27 mesh 35. The mesh 35 disrupts the air flow 9 to create turbulent air flow 24. The mesh 35 28 has dual functionality in that it also acts as a barrier protecting the internal components of 29 the wind energy harvesting device la. As such, it will be appreciated the wind energy harvesting device la may also comprises a mesh across the outlet opening 11 the duct 31 8a.

33 As an additional or alternative feature, the wind energy harvesting device la comprises 34 flow restrictors 36 located within the duct 8a to narrow (or widen) the cross-sectional shape of the passageway, as depicted in Figure 4. The flow restrictors 36 act as a bottle 1 neck increasing the velocity of the air flow 9. The flow restrictors 36 disrupts the air flow 9 2 to create turbulent air flow 24.

4 Generator and Vibration Lens 6 The wind energy harvesting device la further comprises a generator 37 employed to 7 convert movement of the aerofoil 13, 25, in other words the vibrations, into electricity.

9 The generator 37 comprises a vibrational lens 38 and an energy conversion means 39.

The vibrational lens 38 transmits, converges and focuses vibrations from the aerofoil 13, 11 25a, 25b, 25c towards the energy conversion means 39 located within the generator 12 housing 5. The vibrational lens 38 has a dual purpose as is also a means for mounting 13 each aerofoil 13, 25a, 25b, 25c within the plurality of ducts 8.

The vibrational lens 38 may be of a type as described in the applicant's co-pending UK 16 patent publication number GB2586067 and UK patent application number GB2008912.4.

17 As depicted in Figures 3 and 4, the vibrational lens 38 comprises at least two focusing 18 members 40. Each of the at least two focusing members 40 having a first end 41 for 19 attachment to a vibrational source, in this case the aerofoil 13, 25a, 25b, 25c, and a second end 42. The at least two focusing members 40 are arranged such that the 21 separation between the focusing members 40 decreases from the first ends 41 towards 22 the second ends 42.

24 As can be seen in Figures 3 and 4, the first end 41 of each focusing member 40 extends within the aerofoil 13, 25a, 25b, 25c and is attached to the internal structure 31. In 26 addition or alternatively, the first end 41 of each focusing member 40 can be attached to 27 the a surface 14, 15, 18, 19, 21, 22 of the aerofoil 13, 25a, 25b, 25c such as the first side 28 18.

The focusing members 40 depicted in Figures 3 and 4 extend from the first side 18 of the 31 aerofoil 13, 25a, 25b, 25c towards the central axis. As such, the aerofoil 25a with a 32 thickness variation in the span direction, would induce an oscillatory displacement, i.e. 33 linear vibrations in focusing members 40. Conversely, the aerofoil 25a with a thickness 34 variation in the chord direction, would induce an oscillatory twisting motion in the focusing members 40. Furthermore, the aerofoil 25c with both a thickness variation in the chord 1 and span directions, would induce both a combined oscillatory displacement and twisting 2 motion. The movement exhibited by the focusing members 40 is dependent on where the 3 focusing members 40 are attached and the shape and structure of the aerofoil 13, 25a, 4 25b, 25c.

6 Figures 3 and 4 show the focusing members 40 merge towards the second end 42, pass 7 through the generator housing 5a and extend within the generator housing 5a towards the 8 central axis 4. As an alternative, the focusing members 40 may pass through the 9 generator housing 5a and then merge. The focusing members 40 pass through the generator housing 5a by means of a bearing 43 which facilitates the focusing members 40 11 transmitting the movement of the aerofoil 13, 25a, 25b, 25c within the generator housing 5.

12 The type of bearing 43 will depend on the type of movement, for example oscillatory 13 displacement and or twisting, exhibited by the focusing members 40.

The aerofoils 9, 25a, 25b, 25c are designed to oscillate and vibrate at a relatively low 16 frequency between 10 to 50 Hz and a relatively high amplitude equating to a displacement 17 of the second end of the focusing members between 10 and 25 mm. Alternatively, the 18 aerofoils may vibrate at a medium frequency over 50 Hz with a similar relatively high 19 amplitude (10 to 25 mm).

21 The energy conversion means 39 is located at the second end 42 of the vibrational lens 22 38, within the generator housing 5a. As depicted in Figures 3 and 10 the energy 23 conversion means 39 takes the form of a magnet 44 attached to the second end 42 of the 24 focusing members 40 and a coil 45 is located about the magnet 44. The energy conversion means 39 operates on the principle of magnetic induction in that the movement 26 of the magnet 44 relative to the coil 45 creates a changing magnetic flux inducing a current 27 in the coil 45. As can clearly by seen in Figure 10 there are multiple sets of the magnet 44 28 and coil 45 located about the central axis 4, where each set is independently generating 29 electricity.

31 As an additional or alternative feature, the energy conversion means 39 may take the form 32 of piezoelectric crystals.

34 Wind Enemy Harvesting System 1 Figure 11 shows a wind energy harvesting system 46 comprising an array of the wind 2 energy harvesting devices 1 stacked side-by-side and upon each other. As such, the wind 3 energy harvesting system 46 may take the form of a wall, a fence or panels for a structure 4 or building. The wind energy harvesting system 46 may be located in regions of high air flow 9, and particularly high turbulent air flow 24, such as near a motorway, an airport or 6 even on a high-rise building.

8 Alternative Wind Enemy Harvesting Devices In an alternative embodiment, Figure 12 depicts wind energy harvesting device lb 11 comprising a duct 8b connecting the first surface 2b with a tangential third surface 47b of 12 the wind energy harvesting device lb. The third surface 47b is substantially parallel to the 13 central axis 4 and connects the first and second surfaces 2b, 3b. The duct 8b comprises a 14 bend 48 which diverts the air flow 9 originally parallel to the central axis 4 in a tangential direction to the central axis 4. It will be appreciated that the wind energy harvesting device 16 lb may comprise both: ducts 8a connecting the first and second surfaces 2a, 3a as 17 depicted in Figures 1 and 2; and ducts 8b connecting the first and third surfaces 2b, 47b 18 as depicted in Figure 12.

As an additional or alternative feature, the wind energy harvesting device lb as depicted in 21 Figure 12 further comprises a layer of noise insulation 49 attached to the second surface 22 3b of the wind energy harvesting device 1 b. The wind energy harvesting device lb may 23 be a panel for a high-rise building. As such, as well as the wind energy harvesting device 24 lb generating electricity, the noise insulation 49 would provide sound proofing for the building. The noise insulation 49 is particularly suited to the embodiment of Figure 12 as 26 the duct 8b is diverted away from the second surface 3b. Whereas the duct 8a of wind 27 energy harvesting device la depicted in Figure 1 would pass through the additional layer 28 of noise insulation 49.

As a further additional or alternative feature, the wind energy harvesting device lc may 31 comprise a lens 50 for focusing solar radiation 51, as depicted in Figure 13. The lens 50 32 may take the form of a conventional optical lens. The lens 50 is attached to the wind 33 energy harvesting device lc by means of a mounting bracket 52 and orientated to focus 34 solar radiation 51 in the region of the outlet opening 11 of the duct 8c. Consequently, the air at the outlet opening 11 is hotter than the air at the inlet opening 10. In other words, 1 the lens 50 creates a thermal gradient between the inlet opening 10 and outlet opening 11 2 of the duct Sc. This thermal gradient induces a convection air flow, increasing the velocity 3 and kinetic energy of the air flow through the duct Sc. The aerofoils 13 located within the 4 duct 8c may exhibit, for example, higher amplitude vibrations, and this increased vibrational energy can also be captured, focused and converted into electrical energy by 6 the wind energy harvesting device lc. The lens 50 enhances the output of the wind 7 energy harvesting device lc as increases the amount of electricity generated. It will be 8 appreciated that the wind energy harvesting device lc may comprise multiple lenses 50 all 9 orientated towards the outlet openings 11 of the ducts 8c.

11 As a further additional or alternative feature, the energy conversion means 39 may 12 comprise a rotor 53, or more specifically a whirligig-type rotor, connected by an elastic coil 13 connector 54 between the second ends 42 of two focusing members 40 of two vibrational 14 lenses 38, see Figure 14. Each vibrational lens 38 is attached to an aerofoil 13. The oscillatory movement of the second ends 42 of two focusing members 40 stretches and 16 compresses the elastic coil connector 54 which induces the rotor 53 to rotate. This 17 rotatory motion is converted into electricity by a magnet and coil arrangement. The rotor 18 can spin both clockwise and anticlockwise so a pole flipping magnetic generator is 19 required such that electricity can be generated regardless of the rotation direction. In addition, or alternatively, a gear system can be attached to the rotor 53, which turns a 21 secondary wheel or shaft. The gear system will rotate the secondary wheel or shaft 22 irrespective to the direction of the rotor 53.

24 As a further alternative, Figure 15 depicts a cylindrical wind energy harvesting device le comprising a curved surface 55. In this embodiment a duct 8e connects a first region 56 of 26 the curved surface 55 to a second region 57 of the curved surface 55. As can be seen in 27 Figure 15, the ducts Be have different orientations such that the ducts Be each connect 28 different regions of the curved surface 55. As such, the wind energy harvesting device le 29 can advantageously interact with air flows 9 from different directions.

31 As yet a further alternative, Figure 16 depicts a wind energy harvesting device if in the 32 form of a tree structure. The wind energy harvesting device if comprises branch members 33 58. Each branch member comprises a first surface 59, a second surface 60 and ducts 8f 34 connecting the first and second surfaces 59, 60. Each branch member 58 is connected to the generator housing 5f which takes the form of a central column as depicted in Figure 1 16. Advantageously, the branch members 58 may each have different orientations such 2 that the wind energy harvesting device le can also interact with air flows 9 from different 3 directions.

Method of Manufacturing a Wind Energy Harvesting Device 7 Figure 17 shows a flow chart for a method of manufacturing a wind energy harvesting 8 device 1. The method comprises: providing a duct with an inlet and an outlet opening 9 (S1001); providing one or more aerofoils located within the duct wherein a leading edge of the one or more aerofoils is orientated towards the inlet opening (S1002); and providing a 11 generator to convert movement of the one or more aerofoils into electricity (S1003).

13 In addition, the method of manufacturing may optionally comprise characterising the air 14 flow 9, 24. For example, this may include characterising: the mean air flow speed, air flow speed distribution, turbulence, air flow shear profile, distribution of air flow direction and 16 long-term temporal air flow variations.

18 As a further addition, the method of manufacturing may option comprises utilising the 19 characteristics of the air flow 9, 24 to determine the optimum parameters of the wind energy harvesting device 1. For example, this optimisation process may include 21 determining: the dimensions of the wind energy harvesting device 1; the dimension and 22 shape of the ducts 8, the shape and structure of the aerofoils 13, 25a, 25b, 25c; the 23 dimension, shape, material composition, orientation and arrangement of the vibrational 24 lens 38; the relative positioning of two or more aerofoils 13, 25a, 25b, 25c within a duct 8; the arrangement and configuration of features for adjusting the air flow 9 such as the fins 26 32, flaps 34, mesh 35 and flow restrictors 36; and the arrangement and configuration of 27 the generator 37. Optimising the vibrational lens 38 may comprise matching the average 28 resonant frequency across the operational range of the aerofoil 13, 25a, 25b, 25c.

The wind energy harvesting device 1 has numerous advantages. The device does not 31 operate according to aerodynamic lift moving blades and driving a wind turbine. Instead, 32 the energy harvesting device 1 harvests the vibrational energy induced within one or more 33 aerofoils 13, 25a, 25b, 25c and specifically, flutter vibrations induced by counter interacting 34 lift.

1 Advantageously, the wind energy harvesting device 1 can be optimised to operate over a 2 broad range of wind parameters, such as wind speed, reducing the problematic 3 intermittency associated with devices known in the ad.

A further advantage is that the wind energy harvesting device 1 can be compact, is 6 modular and can form part of a larger system 46. The wind energy harvesting device 1 7 and systems 46 can be discretely integrated into the environment in the form walls but are 8 also suitable for locations typically not considered for devices known in the art, such as 9 urban landscapes, motorways and airports. The wind energy harvesting device 1 is not limited to remote areas, often considered areas of natural beauty and so there is no 11 reason for a negative public opinion.

13 Advantageously, the wind energy harvesting device 1 does not comprise relatively large 14 moving external components which can kill birds. The moving components of the wind energy harvesting device 1 are all internal and only exhibit small scale movement such as 16 vibrations. Furthermore, the wind energy harvesting device 1 comprises features which 17 minimise the risk to wildlife such as the mesh 35 which prevents birds from entering the 18 duct 8 through the inlet opening 10.

The wind energy harvesting device 1 can be optimised accordingly to the characteristics of 21 the air flow 9 such that the device 1 is suitable for a broad range of applications. The 22 functionality of the energy harvesting devices 1 can be maximised by incorporating 23 addition features such as noise insulation 49.

A wind energy harvesting device is disclosed. The wind energy harvesting device 26 comprises a duct with an inlet opening and an outlet opening. The wind energy harvesting 27 device further comprises one or more aerofoils located within the duct wherein a leading 28 edge of the aerofoil is orientated towards the inlet opening. The wind energy harvesting 29 device also comprises a generator to convert movement of the one or more aerofoils into electricity. The wind energy harvesting device provides an alternative device for 31 generating renewable energy with numerous advantages. The device harvests vibrational 32 energy, can be optimised to operate over a broad range of wind parameters, has minimal 33 negative environmental impact and is suitable for numerous locations and applications.

1 Throughout the specification, unless the context demands otherwise, the terms "comprise" 2 or "include", or variations such as "comprises" or "comprising", "includes" or "including' will 3 be understood to imply the inclusion of a stated integer or group of integers, but not the 4 exclusion of any other integer or group of integers. Furthermore, unless the context clearly demands otherwise, the term "or' will be interpreted as being inclusive not exclusive.

7 The foregoing description of the invention has been presented for purposes of illustration 8 and description and is not intended to be exhaustive or to limit the invention to the precise 9 form disclosed. The described embodiments were chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others 11 skilled in the art to best utilise the invention in various embodiments and with various 12 modifications as are suited to the particular use contemplated. Therefore, further 13 modifications or improvements may be incorporated without departing from the scope of 14 the invention as defined by the appended claims.

Claims

1 Claims 3 1. A wind energy harvesting device comprising: 4 a duct with an inlet opening and an outlet opening; one or more aerofoils located within the duct wherein a leading edge of the one or 6 more aerofoils is orientated towards the inlet opening; and 7 a generator employed to convert movement of the one or more aerofoils into electricity.9 2. A wind energy harvesting device as claimed in claim 1 wherein, the inlet opening is located on a first surface of the wind energy harvesting device and the outlet opening 11 is located on a second surface of the wind energy harvesting device.13 3. A wind energy harvesting device as claimed in claim 2 wherein, the second surface 14 substantially opposes the first surface, or the second surface is substantially tangential to the first surface.17 4. A wind energy harvesting device as claimed in claim 1 wherein, the inlet opening is 18 located in a first region of a first surface and the outlet opening is located in a second 19 region of the first surface.21 5. A wind energy harvesting device as claimed in any of the preceding claims wherein, 22 the one or more aerofoils comprises a thickness variation in a span and or a chord 23 direction of the one or more aerofoils.6. A wind energy harvesting device as claimed in any of the preceding claims wherein, 26 the wind energy harvesting device further comprises a generator housing, and the 27 generator housing comprises a cone-like portion protruding from the first surface.29 7. A wind energy harvesting device as claimed in claim 6 wherein, the cone-like portion comprises one or more fins.32 8. A wind energy harvesting device as claimed in any of the preceding claims wherein, 33 the wind energy harvesting device further comprises one or more flaps, the one or 34 more flaps are located at the inlet opening of the duct and or at a trailing edge of the aerofoil.2 9. A wind energy harvesting device as claimed in any of the preceding claims wherein, 3 the wind energy harvesting device further comprises a mesh across the inlet opening 4 and or outlet opening.6 10. A wind energy harvesting device as claimed in any of the preceding claims wherein, 7 the wind energy harvesting device further comprises flow restrictors located within the 8 duct.11. A wind energy harvesting device as claimed in any of the preceding claims wherein, 11 the generator comprises one or more vibrational lens and one or more energy 12 conversion means.14 12. A wind energy harvesting device as claimed in claim 11 wherein, the vibrational lens comprising at least two focusing members, each of the at least two focusing members 16 having a first end for attachment to an aerofoil and a second end, wherein the at least 17 two focusing members are arranged such that the separation between the focusing 18 members decreases from the first ends towards the second ends.13. A wind energy harvesting device as claimed in claims 11 or 12 wherein, the vibrational 21 lens comprises a plurality of focusing members wherein two or more aerofoils may be 22 attached the vibrational lens.24 14. A wind energy harvesting device as claimed in claims 11 to 13 wherein, the first ends of the at least two focusing members are attached to the internal structure the aerofoil 26 or to a surface of the aerofoil.28 15. A wind energy harvesting device as claimed in claims 12 to 14 wherein, the at least 29 two focusing members merge towards the second end of the vibrational lens.31 16. A wind energy harvesting device as claimed in claims 12 to 15 wherein, the at least 32 two focusing members pass through the generator housing by means of a bearing.1 17. A wind energy harvesting device as claimed in claims 12 to 16, wherein the energy 2 conversion means is located at the second end of the vibrational lens and the energy 3 conversion means is a magnet and coil or a piezoelectric crystal.18. A wind energy harvesting device as claimed in any of the preceding claims wherein, 6 the wind energy harvesting device further comprises two or more ducts each of the two 7 or more ducts having an inlet opening and an outlet opening, wherein each of the two 8 or more ducts comprise one or more aerofoils located within the duct wherein a leading 9 edge of the one or more aerofoils is orientated towards the inlet opening.11 19. A wind energy harvesting device as claimed in claim 18 wherein, the two or more ducts 12 form one or more branch members for the generator housing.14 20. A wind energy harvesting device as claimed in any of the preceding claims wherein, the wind energy harvesting device further comprises a lens, suitable for focusing solar 16 radiation.18 21. A wind energy harvesting device as claimed in any of the preceding claims wherein, 19 the wind energy harvesting device further comprises a layer of noise insulation.21 22. A wind energy harvesting system comprising two or more wind energy harvesting 22 devices as claimed in any of the preceding claims.24 23. A method of manufacturing a wind energy harvesting device comprising: providing a duct with an inlet opening and an outlet opening; 26 providing one or more aerofoils located within the duct wherein a leading edge of the 27 one or more aerofoils is orientated towards the inlet opening; and 28 providing a generator to convert movement of the one or more aerofoils into electricity.24. A method of manufacturing a wind energy harvesting device as claimed in claim 23, 31 the method of manufacturing a wind energy harvesting device further comprises 32 characterising an air flow.34 25. A method of manufacturing a wind energy harvesting device as claimed in claim 24, the method of manufacturing a wind energy harvesting device further comprises 1 determining the optimum parameters of the wind energy harvesting device for use with 2 the air flow.1 Claims 3 1. A wind energy harvesting device comprising: 4 a duct with an inlet opening and an outlet opening; one or more aerofoils located within the duct wherein a leading edge of the one or 6 more aerofoils is orientated towards the inlet opening; and 7 a generator comprising one or more vibrational lenses and an energy conversion 8 means, the generator employed to convert movement of the one or more aerofoils into 9 electricity, wherein the one or more vibrational lenses focus vibrations from movement of the one 11 or more aerofoils to the energy conversion means.13

2. A wind energy harvesting device as claimed in claim 1 wherein, the inlet opening is 14 located on a first surface of the wind energy harvesting device and the outlet opening is located on a second surface of the wind energy harvesting device.C\I 17

3. A wind energy harvesting device as claimed in claim 2 wherein, the second surface 0) 18 substantially opposes the first surface, or the second surface is substantially tangential CD 19 to the first surface. CD 2021

4. A wind energy harvesting device as claimed in claim 1 wherein, the inlet opening is 22 located in a first region of a first surface and the outlet opening is located in a second 23 region of the first surface.

5. A wind energy harvesting device as claimed in any of the preceding claims wherein, 26 the one or more aerofoils comprises a thickness variation in a span and or a chord 27 direction of the one or more aerofoils.29

6. A wind energy harvesting device as claimed in any of the preceding claims wherein, the wind energy harvesting device further comprises a generator housing, and the 31 generator housing comprises a cone-like portion protruding from the first surface.33

7. A wind energy harvesting device as claimed in claim 6 wherein, the cone-like portion 34 comprises one or more fins.1

8. A wind energy harvesting device as claimed in any of the preceding claims wherein, 2 the wind energy harvesting device further comprises one or more flaps, the one or 3 more flaps are located at the inlet opening of the duct and or at a trailing edge of the 4 aerofoil.6

9. A wind energy harvesting device as claimed in any of the preceding claims wherein, 7 the wind energy harvesting device further comprises a mesh across the inlet opening 8 and or outlet opening.

10. A wind energy harvesting device as claimed in any of the preceding claims wherein, 11 the wind energy harvesting device further comprises flow restrictors located within the 12 duct.14

11. A wind energy harvesting device as claimed any of the preceding claims wherein, the one or more vibrational lenses comprises at least two focusing members, each of the 16 at least two focusing members having a first end for attachment to an aerofoil and a C\I 17 second end, wherein the at least two focusing members are arranged such that the (3) 18 separation between the focusing members decreases from the first ends towards the CD 19 second ends. CD 2021

12. A wind energy harvesting device as claimed in any of the preceding claims wherein, 22 the one or more vibrational lenses comprises a plurality of focusing members wherein 23 two or more aerofoils may be attached the one or more vibrational lenses.

13. A wind energy harvesting device as claimed in either claims 11 or 12 wherein, the first 26 ends of the at least two focusing members are attached to the internal structure the 27 aerofoil or to a surface of the aerofoil.29

14. A wind energy harvesting device as claimed in claims 11 to 13 wherein, the at least two focusing members merge towards the second end of the one or more vibrational 31 lenses.33

15. A wind energy harvesting device as claimed in claims 11 to 14 wherein, the at least 34 two focusing members pass through the generator housing by means of a bearing.1

16. A wind energy harvesting device as claimed in claims 11 to 15, wherein the energy 2 conversion means is located at the second end of the one or more vibrational lenses 3 and the energy conversion means is a magnet and coil or a piezoelectric crystal.

17. A wind energy harvesting device as claimed in any of the preceding claims wherein, 6 the wind energy harvesting device further comprises two or more ducts each of the two 7 or more ducts having an inlet opening and an outlet opening, wherein each of the two 8 or more ducts comprise one or more aerofoils located within the duct wherein a leading 9 edge of the one or more aerofoils is orientated towards the inlet opening.11

18. A wind energy harvesting device as claimed in claim 17 wherein, the two or more ducts 12 form one or more branch members for the generator housing.14

19. A wind energy harvesting device as claimed in any of the preceding claims wherein, the wind energy harvesting device further comprises a lens, suitable for focusing solar 16 radiation.C\I 17 (3) 18

20. A wind energy harvesting device as claimed in any of the preceding claims wherein, CD 19 the wind energy harvesting device further comprises a layer of noise insulation.(r) 20 21

21. A wind energy harvesting system comprising two or more wind energy harvesting 22 devices as claimed in any of the preceding claims.24

22. A method of manufacturing a wind energy harvesting device comprising: providing a duct with an inlet opening and an outlet opening; 26 providing one or more aerofoils located within the duct wherein a leading edge of the 27 one or more aerofoils is orientated towards the inlet opening; and 28 providing a generator comprising one or more vibrational lenses and an energy 29 conversion means, the generator employed to convert movement of the one or more aerofoils into electricity, 31 wherein the one or more vibrational lenses focus vibrations from movement of the one 32 or more aerofoils to the energy conversion means.1

23. A method of manufacturing a wind energy harvesting device as claimed in claim 22, 2 the method of manufacturing a wind energy harvesting device further comprises 3 characterising an air flow.

24. A method of manufacturing a wind energy harvesting device as claimed in claim 23, 6 the method of manufacturing a wind energy harvesting device further comprises 7 determining the optimum parameters of the wind energy harvesting device for use with 8 the air flow.