CA2565380A1

CA2565380A1 - Natural fluid energy extraction system

Info

Publication number: CA2565380A1
Application number: CA002565380A
Authority: CA
Inventors: Changlin Feng
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-10-23
Filing date: 2006-10-23
Publication date: 2008-04-23

Abstract

The invention is directed to an apparatus and method for extracting energy from the motion of natural fluids, said apparatus comprising: a) a base; b) at least two tracks attached to said base, said tracks moveable relative to said base; c) a plurality of sails coupled to said tracks, said sails being adjustable relative to said tracks between a position substantially perpendicular to said tracks and substantially parallel to said tracks and operative to moveably drive said tracks via movement of said fluid when said sails are in said substantially perpendicular position; d) a channel, said channel formed between said tracks and said base, said channel including sail engagement means to engage said sails and move said sails into a position substantially perpendicular to said tracks and operative to allow said sails to return to an initial operating position with reduced resistance to said fluid; and e) an electric generator system, said generator system operative to convert movement of said tracks into electricity.

Description

NATURAL FLUID ENERGY EXTRACTION SYSTEM
Field of the Invention 100011 The present invention relates to the field of renewable energy. In particular, it relates to a system of extracting useful energy via the conversion of kinetic energy from moving fluids.

Background of the Invention [00021 One of the challenges facing global society as it progresses in the 21 st century is the shortage of energy, such as electricity. Coincident with this challenge is the stress and damage to the environment arising from excessive consumption of fossil fuels, particularly in the areas where renewal energy sources can be used, again such as electricity generation. As a result, substantial research and development has been put into alternative and renewable energy resources, including fluid-driven devices such as windmills and waterwheels (i.e. water-driven turbines).
[ooo31 Waterwheels and windmills were some of the earliest devices to make use of the flow of natural fluids to create power for human beings. Since then, great efforts have been made to extract energy, particularly with turbine technology, from natural fluids. The major challenge is that with current technologies the energy potential of natural fluid media is too low to drive large capacity machines. As a result, it is not currently possible to achieve an economical scale of high efficiency energy extraction by operating single units. Nowadays, except for hydraulic turbines used in hydroelectric power generation from rivers and dams, all the other technologies, including windmills, wave mills and tidal current turbines, have to be run in a farm-style operation featuring multiple units with each unit having a limited capacity due to size constraints.
[00041 Referring to the turbine technology for wind energy, two types of wind turbines, horizontal axis wind turbines (HAWTs) and vertical axis wind turbines (VAWTs), are in use. It is known that single HAWT units are currently capable of being produced in the megawatt-scale. With multiple units, windmills can be developed into a farm-style operation to generate electricity on a commercial scale.
Nevertheless, it is - I - File No.76272-1 (KB) extremely difficult to further improve HAWTs technology for single units because the practical limits, not only in mechanical structure, but also in transportation and installation, have been reached. With respect to VAWTs, no feasible products are available on the market although variations on the Darrieus machine have been attempted (as originally shown in U.S. Patent No. 1,835,018, to Darrieus).
[00051 As to other extracting technologies, several prototype tidal or wave energy devices, such as the Pelamis device from Ocean Power Delivery Ltd. (based on U.S.
Patent No. 6,953,328, to Welch, Jr.), the Wave Dragon from Wave Dragon A/S, the Limpet from Wavegen and the Stingray from Tidal Energy Business, all represent the leading edge of commercial development for this technology. The Pelamis and Stingray tidal devices take advantage of tidal waves to capture the kinetic energy by hydraulic pump systems, while the Wave Dragon and Limpet devices still adopt turbine technology. However, none of them have overcome the limitations mentioned above and the current prototypes operate at less than 1 MW capacity and according to their producers, currently project out to around 3-5MW in the future.

100061 In addition to the turbine and other technologies recited above, other systems have also been developed to convert the flow of natural fluids into electrical energy. U.S.
Patent No. 1,502,296 to Doak discloses a fluid-current motor, comprising a spreader with two pairs of pulleys mounted at the extremities of the shafts. A series of impellers, which are attached on the chain belts connected through the pulleys, are used to capture the flowing wind. The impellers can only contribute to power output in the concurrent fluid flow in the driving section. In the returning section the impellers cause resistance because they move counter to the fluid flow.
[0007] Canadian Patent No. 1,117,022 to Cocjin discloses a wind energy machine, with a number of moving sails, a wind deflector and an energy intensifier, for capturing the kinetic energy of wind. The employment of wind deflector and intensifier reduces the resistance of sails to some extent in the returning process. However, the efficiency of this wind machine is decreased by the counter current caused by the shielded supporter. Also, the angled elevation construction requires more space and is not suited to areas with unstable geology.

- 2, - FileNo.76272-1(KB) 100081 U. S. Patent No. 3,882,320 to Schmeller discloses a tide energy conversion device with a plurality of blades and a fixed flow channel. The tide flow pushes the blades, which are connected to sprockets via chains, in the channel to accomplish the energy conversion. As a result, only the tide flow that comes into the channel can take part in the energy conversion. However, the drag forces of the fluid are seriously reduced due to the damping effects of the fluid media by previous blades.
100091 U. S. Patent No. 4,049,300 to Schneider discloses an apparatus for generating electric current by the force of a fluid in motion. Instead of drag force, this apparatus make use of the lift force, which is generated by the aerodynamic blades, to capture the kinetic energy of the fluid. Through detailed mechanical design, the exhausted fluid from the first stage is regulated by stators, and exerts a positive reaction force on the returning blades in the second stage.
[00101 So far, there are no feasible methods, except hydraulic turbines and some aspects of HAWTs technology, to extract the kinetic energy from natural fluids for power generation on a commercial scale, although some inventions and prototype devices have been brought into operation. More generally, the low energy potential in natural fluids is unable to drive individual units with enough power generation capacity to achieve commercial scales, as seen with windmills operating under present technologies. In order to compete with other power generating technologies, the limited capacity of an individual unit leads to a farm-style operation with multiple units. It significantly increases the fundamental costs of the operation, such as manufacture, transportation, construction and installation. In addition, it increases the costs in operation, maintenance and connection to the electrical network, and can lead to other environmental problems, for example, the windmill farm can interfere with the migration of birds, generate annoying noise and distort television and radio signals.
100111 For operation with a given natural fluid, in order to increase the capacity of a single unit two critical problems need to be addressed: 1) the swept area of the sails/foils must be enlarged; and 2) the resistance of the sails/foils in returning process must be reduced. However, the difficulty in creating an improvement lies in that these two elements are connected, as an increase in swept area tends to result in an increase in resistance, partially (or even totally) negating the effect. For horizontal axis apparatus, it

- 3 _ File No.76272-I (KB) is very difficult to improve on the turbine technology because limits in mechanical design, transportation and installation, have effectively been reached. For vertical axis apparatus, no realistic methods to reduce the resistance of sails/foils in the returning process have been created, although efforts have been ongoing in the last few decades.
100121 An alternative energy extraction system is needed which is capable of generating power on a commercial scale without encountering the limitations shown in the prior art.
100131 A primary object of the present invention is to overcome and avoid the disadvantages and inefficiency of existing technologies mentioned above, and to provide an apparatus which can be built to a considerable capacity with an individual unit.
[00141 Another object of the invention is to provide a vertical axle apparatus which can be used to capture the kinetic energy of natural fluids, and then convert it into rotational, mechanical or electrical energy. The angles of the sails for the apparatus are oriented in accordance with the flow direction of fluids so that in the returning process the resistant of sails is reduced to a minimum.
[00151 Another object of the invention is to provide an apparatus, which is simple in design, economical in manufacture, easy in construction and reliable in operation.
[0016] Still another object of the invention is to enable the apparatus, to be used with a variety of natural fluids, such as wind, water, waterfalls, rivers, tidal waves and ocean currents.

Summary of the Invention [00171 According to an aspect of the invention there is provided an apparatus and method for extracting energy from the motion of a fluid, said apparatus comprising: a) a base; b) at least two tracks attached to said base, said tracks moveable relative to said base; c) a plurality of sails coupled to said tracks, said sails being adjustable relative to said tracks between a position substantially perpendicular to said tracks and substantially parallel to said tracks and operative to moveably drive said tracks via movement of said fluid when said sails are in said substantially perpendicular position; d) a channel, said channel formed between said tracks and said base, said channel including sail engagement means to engage said sails and move said sails into a position substantially

-4- File No.76272-1(KB) perpendicular to said tracks and operative to allow said sails to return to an initial operating position with reduced resistance to said fluid; and e) an electric generator system, the electric generator system operative to convert movement of said tracks into electricity. Preferably, the natural fluid is either wind or water.
[0018] Also preferably, multiple apparatuses containing elements (a) - (d) can be combined to drive a single generator of larger size than generators driven by a single apparatus.
[00191 The present invention provides several advantages over the prior art, including the ability to combine multiple apparatus to drive a single generator, and to provide greater power output than existing HAWTs and VAWTs designs.
[00201 Other and further advantages and features of the invention will be apparent to those skilled in the art from the following detailed description thereof, taken in conjunction with the accompanying drawings.

Brief Description of the Drawings 100211 The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings, in which like numbers refer to like elements, wherein:

Figure 1 is a schematic side view of the apparatus of the present invention;
Figure 2 is a cross-section view along the line 2-2 which is shown in Figure 1;
Figure 3 is another partial cross-section view along the line 3-3 of Figure 1;

Figure 4 is an enlarged cross-section view of the endless chain and the attachment point of the sails to the endless chain;

Figure 5 is an enlarged side view of the assembly shown in Figure 4;

Figure 6 is a representational diagram to show the arrangement of present apparatus with a gearbox and electrical generator;

- 5 - File No.76272-t (KB) Figure 7 is a schematic illustration of the combination of three apparatuses into one unit to drive a large electrical generator; and Figure 8 is a schematic illustration of another embodiment of the present invention with four parallel axles.

Detailed Description of the Preferred Embodiments [0022] Within this specification, "sails" are defined as any element, rigid or flexible, used to provide resistance to a natural fluid and move along a track in accordance with the device described and claimed herein.
[0023] A preferred embodiment of an energy extracting apparatus according to the present invention is shown in Figure 1. As shown, the apparatus comprises a support frame 17, which is fastened on a base supporter (not shown in the drawing).
The overall direction and inclination of the apparatus can be adjusted using the base supporter. In this way, the apparatus can be aligned to optimize its direction with the direction of the flow of the fluid media. It is to be understood that the base supporter is not specifically illustrated in present invention because it is a standard requirement in this field. The configuration of the base supporter is determined by the circumstances of its application (i.e. wind, water, tidal, etc.). On the frame 17, two parallel axles 18 and 19 are positioned in an extending plane, and two pairs of matched sprockets 13, 14, and 15, 16 are mounted at extremities of axles 18 and 19, together with an endless chain 8, 9 and chain guardrails 4, 5, and 24, 25 to form a circulating loop for the moving sails 10. It is to be understood that the number of axles is not critical to the invention so long as they can make up a structure to compose the circulating loop for moving sails 10. Obviously, at least two axles are needed to form a circulating loop.
[0024] Two slide blocks, which are used to support the axle 19, are positioned at the end of frame 17. By using screws 20 and 21, the tension of endless chains 8, 9 can be adjusted. It is within the scope of the present invention that any other type of transmission belts or chains can be utilized so long as the desired result is achieved, although the endless chains are preferred. A preferred type of endless chain is the type known as a free flow chain, where the chain links are additionally supported by wheels

-6- File No.76272-I (KB) that sit in chain rails 4, 5 and 24, 25 to assist in supporting very long chains. As can be seen in Figure 2, the sails 10 are hooked up to endless chains 8, 9 along their shafts 35 via couplings 36 (shown in more detail in Figures 4 and 5).
[00251 With reference to Figure 3, chain rails 4, 5 have positioned adjacent and parallel upper guide wheel tracks 6, 7, which are positioned on the frame 17 by braces 33.
Referring again to Figure 1, the upper guiding wheel tracks 6, 7 have a U
shape and curves in both ends. It is to be understood that the guiding wheels on the sails 10 and wheel tracks 6, 7 are not exclusive to the present invention and other equivalent mechanical configurations can be applied in order to regulate and adjust the angle of the sails 10. In the lower part of the apparatus, there is another pair of guide tracks 22, 23, which are fixed externally to the main structure by braces 33. The tracks 22, 23 combine with shield shell 30 and louver windows 29 to form a buffer area at the end of the driving course for the incoming sails 10.

[00261 The shield shell 30 can be installed to shelter the sails 10 and to further reduce the resistance of sails 10 in the returning course. In the buffer area, on the bottom of shield shell 30, the louver windows 29 are utilized to moderate the impact caused by the advancing sails 10, which permits them to be smoothly oriented with the returning direction of the chains 8, 9. When the returning course finishes, the guide tracks 22, 23 are interrupted underneath the sprockets 13, 14 to provide a space for the turnover of sails 10. In order to align guide wheels 28 to enter the wheel tracks 6, 7 at the beginning of a new cycle, a clip switch 31 and motor 32 are installed on tracks 26, 27.

[00271 A series of sails 10 are uniformly attached by shafts 35 as shown in Figure 4, to endless chains 8, 9. On every sail 10 a pair of guide wheels 28, and a pair of small guide wheels 11, as shown in Figure 2, are attached respectively. It is to be understood that the shape of the sails 10 is not restricted other than as necessary to fulfill the function of engaging the fluid. However, in order to reduce the resistance of sails 10 in the returning course, a preferred cross-section of the sails 10 has been carefully designed according to fluid dynamic principles. The resulting preferable cross-sectional configuration is an elongated concavoconvex shape. The concave side is placed to face the flow of the fluid in the driving course by the guide wheels 28 and wheel tracks 6, 7.
While in the returning course, the sails 10 are oriented via guide wheels 11 and the - '] - File No.76272-I (KB) guiding track 22, 23 to be parallel to the flow of the fluid. As a consequence, the resistance of sails 10 to the fluid has been reduced to a minimum in the returning course.
It is to be understood that the shape of sails 10 are determined by properties of fluid media and the application conditions. For example, the sails 10 can be ladle or scoop-shaped when the invention is applied to waterfalls. It is within the scope of the present invention that other shapes and configurations of sails 10 can be adopted so long as the desired result is achieved.
[00281 There are no particular restrictions on the number and size of sails 10.
According to fluid dynamic principles, when the fluid passes a sail 10, the velocity of the fluid will be damped down and cause a bound vortex behind the sail 10. In considering the above factors, the distance between sails 10 should be larger than the distance of fluid damping and bound vortex area behind each sail 10. The distance will be determined by the nature and flow strength of the fluid in question. To minimize the damping effects of the fluid and take full advantage of using multiple sails 10 in the driving course, the apparatus can be oriented to an optimizing angle to the flow of the fluid.
With respect to the size of the sails 10, this is mainly restricted by the sprocket size and the gaps between guide tracks 22, 23 and sprockets 13, 14. At the end of the returning course, there should be enough space to allow the sails 10 to turn over and pass through. It is to be understood that the materials for the sails 10 are not critical to the invention.
Accordingly, the sails 10 can be made of any desired materials, preferably chosen from metal, wood, polymer composites with fiberglass, cloth and plastic materials, etc. The exact choice of the preferred material will be determined by the fluid being used to drive the apparatus.
[00291 With reference to Figure 1, the circulating of sails 10 is described below. In the driving course, the sails 10 will be kept in a substantially perpendicular position relative to the chain rails 4, 5 which are held in position by the guide wheels 28 and wheel tracks 6, 7. The flowing fluid media will exert drag forces on every sail 10 to move them along tracks 6, 7. As the sails 10 move, the endless chains 8, 9 will rotate the sprockets 13, 14, and via shaft 18 the kinetic energy of the moving fluids (through the sails 10) will be transformed into rotational mechanical energy.
100301 When the sails 10 arrive at the end of the driving course, the angle of sails 10 to the chain rails 4, 5 will increase because the guide wheel tracks 6, 7 gradually - g - FileNo.76272-I(KB) approach the chain rails 4, 5. Accordingly, the drag force, which is exerted by the flow motion of the fluid, will be reduced to some extent. With that movement, the small guide wheel 11 on top of the sail 10 will touch the wheel track 22, 23, meanwhile the guide tracks 6, 7 are interrupted, and the guide wheels 28 will be released. Thus, the sails 10 are free to rotate about the axle 34. When the sails 10 enter the channel, the impact is greatly moderated by the air cushion at the entrance of the channel. The cushion intensity can be carefully adjusted by the opening of louver windows 29 so that no surplus resistance is generated.
[0031] The guide wheels 11 and guide tracks 22, 23 guide the sails 10 to be oriented parallel to the surface of the chain rails 4, 5 in the returning course.
Hence, the resistance of sails 10 to the fluid media is greatly reduced. At the end of the returning course, the guide tracks 22, 23 are interrupted. When arriving at this point, the sail 10 will be in a cantilevered position which is upside down. The top of the sail 10 will rapidly swing towards the guide tracks 26, 27. The clip switch 31 catches the top of the sail 10, and the motor 32 is turned on. The top of the sail 10 will then be carried by motor 32 and quickly moved up along tracks 26, 27. The endless chains 8, 9 are continually moving forward during this process. With the assistance of motor 32, the guide wheels 28 are forced to enter the guide tracks 6, 7 as the sail 10 rises towards the starting position. After the guide wheels 28 enter the guide tracks 6, 7, the clip switch 31 will release the top of the sails 10. The sails 10 thus enter a new cycle on the driving course and begin another journey on the circulating loop.
[00321 In certain applications, the clip switch 31 and motor 32 can be eliminated from the design. For example, in a river or similar water-driven application, the driving course is located on the underside of the frame 17 and the force of gravity acting on the sails 10 can be used to reposition the sails 10 at the end of the returning course. Other alternatives can be devised for specific applications that perform essentially the same function as the clip switch 31 and motor 32.

[0033] While the sails 10 as shown are alternately adjusted between a position fully perpendicular to the rails 4, 5 and a position fully parallel to the rails 4, 5, depending on the nature of the fluid and its surroundings, the sails can be adjusted to positions in between. Furthermore, in some cases where the returning track is not passing through the - 9 - File No. 76272-1 (KB) fluid, i.e. when used on a river, the sails 10 may not need to be adjusted for the returning course.
100341 In Figure 6, a representational connection of the present invention to a gearbox and electrical generator is shown. The kinetic energy of the fluid is converted by the moving sails 10 into rotational mechanical energy, which is transmitted from axle 18 to gearbox 45, and then to electrical generator 46. The gearbox is used to increase the rotational speed in the generator 46 because the movement of sails 10 on a vertical axle apparatus will be relatively slow. In addition to the gearbox 45, a clutch may be applied to prevent damage to the apparatus in emergencies. It is to be understood that there is an optimizing angle, 0, between the movement direction of the sails 10 and the flow direction of the natural fluid, as shown by the large arrow in Figure 6. With the angle 0 optimized, the damping effects from the previous sail 10 to the next sail 10 are comparatively reduced, and all the sails 10 are more or less equally impelled by the flow of the fluid. Concurrently, this optimization allows the maximum amount of force to be exerted on the sails 10 by the fluid.
[00351 It is to be further understood that the arrangement of apparatus with electrical generator 46 is not critical to the invention so long as the electrical generator 46 is being driven. In reference to Figure 7, a larger version of the present invention incorporating three apparatuses is schematically illustrated. It can be seen that three (or more) apparatuses can be combined into a unit to drive a large electrical generator.
[00361 Another embodiment of the present invention with four axles is schematically shown in Figure 8. In order to reduce the resistive forces of sails 10 during an idle course, a flexible moving shell 48, which is driven by a motor along the tracks, is used to shield the moving sails 10 from the force of the fluid in the adjacent region.
In this embodiment, it is unnecessary to align the direction of sails 10 with flow direction of the fluid. The sails 10 will be automatically lifted up or pulled down under the pressure of the fluid. The electrical generator 46 is installed inside of the frame in this multi-axle configuration. This arrangement is suitable for reduced space areas, such as for placement on the top of a building.

100371 Accordingly, the invention can be constructed in various configurations with a proper support frame 17 and applied to different natural fluids, such as rivers, waterfalls, -10- File No.76272-1 (KB) wind, tidal waves and ocean currents, whether it is submersed inside or floating on the surface of the natural fluid media.
100381 This concludes the description of a presently preferred embodiment of the invention. The foregoing description has been presented for the purpose of illustration and is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teaching and will be apparent to those skilled in the art. It is intended the scope of the invention be limited not by this description but by the claims that follow.

- 1 1 - File No.76272-1(KB)

Claims

What is claimed is:

1. An apparatus for extracting energy from the motion of a fluid, comprising:
a) a base;

b) at least two tracks attached to said base, said tracks moveable relative to said base;

c) a plurality of sails coupled to said tracks, said sails being adjustable relative to said tracks between a position substantially perpendicular to said tracks and substantially parallel to said tracks and operative to moveably drive said tracks via movement of said fluid when said sails are in said substantially perpendicular position, said sails further being positioned at an angle relative to said base such the force exerted by said fluid upon each sail is maximized;

d) a channel, said channel formed between said tracks and said base, said sails moving to a position substantially parallel to said tracks upon entering said channel and returning to a position substantially perpendicular to said track upon exiting said channel ; and e) an electric generator system, said electric generator system operative to convert movement of said tracks into electricity.

2. The apparatus according to claim 1, wherein said fluid is water.

3. The apparatus according to claim 1, wherein said fluid is wind.

4. The apparatus according to any of the preceding claims, wherein said channel further includes at its exit area sail engagement means to engage said sails and adjust said sails into a position substantially perpendicular to said tracks and operative to allow said sails to return to an initial operating position with reduced resistance to said fluid.

5. The apparatus according to any of the preceding claims, wherein said channel further includes at its entrance area an adjustable shield capable of reducing resistance of sails entering said channel to said fluid.

6. The apparatus according to any of the preceding claims, wherein each of said tracks consists of an endless chain coupled to a pair of sprockets.

7. The apparatus according to claim 6, wherein said endless chain is a free flow chain.

8. The apparatus according to any of the preceding claims, wherein said sail engagement means is motor-driven.

9. The apparatus according to any of the preceding claims, wherein said generator system is connected to multiple apparatuses containing elements (a) - (d).

10. The apparatus according to any of the proceeding claims, wherein said tracks run over two parallel axles.

11. The apparatus according to any of claim 1-9, wherein said tracks run over more than two parallel axles.

12. A method of extracting energy from the motion of a fluid, comprising:

a) coupling one or more fluid motion apparatuses to an energy extraction system, each of said one or motion fluid motion apparatuses including:

i) a base;

ii) at least two tracks attached to said base, said tracks moveable relative to said base;

iii) a plurality of sails coupled to said tracks, said sails being adjustable relative to said tracks between a position substantially perpendicular to said tracks and substantially parallel to said tracks and operative to moveably drive said tracks via movement of said fluid when said sails are in said substantially perpendicular position; and iv) a channel, said channel formed between said tracks and said base, said channel including sail engagement means to engage said sails and move said sails into a position substantially perpendicular to said tracks and operative to allow said sails to return to an initial operating position with reduced resistance to said fluid.

13. The method of claim 12, wherein said fluid is water.

14. The method of claim 12, wherein said fluid is wind.