SG177024A1 - Vertical-axis wind-turbine with stacked propellers and an inground road installation - Google Patents

Abstract

VERTICAL-AXIS WIND-TURBINE WITH STACKED PROPELLERS ANDAN INGROUND ROAD INSTALLATIONA vertical-axis wind-turbine with a rotor comprising one or more propellersassembled in a stack, each propeller having at least three rotor blades which caneither be of a similar design as a fan blade of an axial or a diagonal fan or be of asimilar design as an airfoil with a convex leading edge and a concave trailing edge.The rotor blades of each propeller can be offset at a horizontal angle (as seen alongthe longitudinal axis of the rotor) from the rotor blades of the adjacent propeller,creating a rotor with a helix-shape arrangement of rotor blades. A method ofinstalling such a wind-turbine with a rotor diameter of less than 300 millimetersinground below a road surface is also proposed.For an application of the present invention, please refer to Fig.1a.

Description

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VERTICAL-AXIS WIND-TURBINE WITH STACKED PROPELLERS AND : © ANINGROUND ROAD INSTALLATION . - FIELD OF INVENTION - | B oo

B ‘The invention is in the field of renewable energy, in particular, capturing and : converting wind energy to useful electrical, hydraulic or pneumatic energy. —

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BACKGROUND OF THE INVENTION & PRESENT STATE OF THE ART

Due to the threats of global warming, governments and organisations world-wide are : looking into ways of tapping renewable energy sources like solar, wind, waves and oo geothermal in order to reduce carbon emissions and to obtain carbon credits. -

For wind energy, the most common wind-turbines are the horizontal-axis wind- turbines (HAWTSs) and vertical-axis wind-turbines (VAWTs). Though VAWTs have a number of advantages over HAWTs (less bird-kills, ease of maintenance, generators can be placed nearer to the ground and ability to handle turbulent wind- flow), these advantages are often negated by their inherent designs and construction : which are mainly of the Savonius drag-type or Darrieus lift-type designs. HAWTs - are more efficient, produces less drag, can be bigger in size and produce more power than VAWTs. They also require about half the construction materials (excluding masts) needed for a VAWT. As a result HAWTs are more widely. adopted in commercial wind-farms. :

Various attempts have been made to make VAWTs more efficient. US patents 5852331, 6749393 and * 7365448 and US applications 2009/0087300 and 2009/0261596 describe an enclosure or housing to direct the air towards the rotor blades of a Savonius-type rotor to boost power output. US patents 6015258, 6191496, 6465899 and 6740989 describe the use of stator vanes to direct air towards a Savonius-type rotor and to increase the speed of rotation of the rotor blades as they ~ passed by the" stator vanes. Further, US patent 7008171 and US application : 2009/0087300 describe a method of stacking multiple layers of rotor blades to form the rotor of a VAWT. :

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The rotor blades of a Darrieus-type VAWT suffer from drag and torsional problems in more than fifty percent of the time during the rotation of the rotor blades. US - Lo

Application 2009/072116 describes a hollow section at the trailing edge of a rotor blade with an airfoil design. US Application 2010/0084863 describes a variable vane design of a Darrieus-type VAWT to reduce the drag on the rotor blades. oo

However, all the above methods of improving the efficiency and power output of the

Bn VAWTs only make incremental improvements and are insufficient to improve the competitiveness of the VAWTS against the HAWTS. oo + Therefore, there is a need for a more efficient design of a VAWT which requires less construction materials and can be larger in size, resulting in greater power output.

A specific claim of the current invention is the installation of a small-sized and long oo ~ VAWT (with a rotor diameter of less than three hundred millimeters) inground and : approximately flush with a road surface to capture the wind-drafts created by the motor vehicles on top of the road surface. This claim is an improvement of my recent

Bh patent application named “IN-GROUND IN-LINE ROAD WIND-TURBINE

SYSTEM” which uses multiple inground air-ducts, each air-duct having multiple ~ wind-turbines.

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Various attempts have been made to install wind-turbines as part of the transportation _ networks or landscape surrounding these networks. There are designs to incorporate ° * wind-turbines as part of road safety barriers or road dividers, or along overhead bridges or gantries. | oo

US patents 7547984 and 7525210 detail methods of installing and interconnecting wind-turbines near highways and road intersections. WO 2008/133872 details a : method of installing wind-turbines at various coordinated heights and distances to - maximise the capture of the wind energy. US patent application 12/360327 details a combination of fixed and mobile wind-turbines around roads. :

However, all these current methods or systems of installing wind-turbines are not satisfactory as often these wind-turbines do not fit aesthetically with the transport networks and physical surroundings. Also, the amount of energy captured will be - limited if these wind-turbines are installed at a distance away from the movement of : the motor vehicles.

Therefore, there is a need for a simpler and more efficient way of capturing the wind energy created by the motion of the motor vehicles by creating an inground road wind-turbine system. . | | oo ‘

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OBJECTS OF THE PRESENT INVENTION | | oo

It is an object of the present invention to create a simpler, more efficient and more - powerful vertical-axis wind-turbines (VAWTs) with a stack of propellers. -

It is another object of the present invention to create a large VAWT which can be lighter and which require less construction materials.

It is also another object of the present invention to create a VAWT which can have longer rotor blades to create a bigger wind-swept area.

It is yet another object of the present invention to create a VAWT which can compete with existing horizontal-axis wind-turbines (HAWTs) in commercial wind-farms. Ttis also yet another object of the present invention to create a VAWT which can be compact enough to fit on highways, commercial buildings and residential houses.

It is a further object of the present invention to create small VAWT which can be mounted inground and approximately flush to a road surface the capture the wind- drafts created by motor vehicles moving on the road surface. SE Bh

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SUMMARY OF THE PRESENT INVENTION .

Under the present invention, the new vertical-axis wind-turbine (VAWT) has a rotor which incorporates the advantages of the traditional Savonius and Darrieus VAWT rotors with the propeller rotors used in horizontal-axis wind-turbines (HAWTS).

The new rotor comprises one or more propellers mounted as a stack on its rotor shaft such that all the propellers rotate in unison on a plane which is generally perpendicular to the axis of rotation of the rotor. Each propeller has at least three rotor blades which can either be of a similar design as a fan blade of existing axial, ‘mixed-flow or diagonal fan or be of a similar design as an airfoil with a convex leading edge and a concave trailing edge. The rotor blades of each propeller can also be offset at a horizontal angle (as viewed along the longitudinal axis of the rotor) ~~ from the rotor blades of an adjacent propeller, creating a rotor with a helix-shape ~ arrangement of rotor blades. The rotor blades are designed such that they capture and maximise the force of the wind when rotating in the same direction as the wind while minimizing the wind drag forces when rotating against the direction of the wind.

The rotor blades can be made of metal or plastic materials or a combination of such materials. The propellers can be made small with a diameter of between one hundred to three hundred millimeters, similar to that for the axial or diagonal fans used for cooling computers or electronic equipment. This allows the wind-turbine to be installed on road safety barriers, road tunnels, building roofs and building walls. The small. wind-turbine with a stack of propellers can be installed either in a vertical, horizontal or inclined position and air-vanes can be installed around the circumference of the stator frame to further capture the wind flow.

oo : 7. ~~ The propellers can also be made larger with a diameter of between one to ten meters - which allows the wind-turbines to be used in commercial wind-farms, competing : against the existing HAWTs. The larger and longer propellers in a stack can be physically linked to each other and supported by stay wires attached to the rotor and can also be supported by rollers or wheels on the ground or the stator frame of the

B wind-turbine. Wind-vanes and air-guides can also be incorporated around the - circumference of the stator of the wind-turbine to direct wind onto the rotor to maximise power output. | | | oo

The rotor shaft can be connected to an electrical generator, or a hydraulic or pneumatic. pump which is linked to a hydraulic or pneumatic system respectively to . generate hydraulic or pneumatic energy respectively. An electrical generator can also be incorporated in the hydraulic or pneumatic system to generate electricity. oo

A specific claim of the current invention is the installation of a small-sized and long

VAWT (with a rotor diameter of less than three hundred millimeters) inground and flush with a road surface to capture the wind-drafts created by the motor vehicles on "top of the road surface. This claim is an improvement of my recent patent application named “IN-GROUND IN-LINE ROAD WIND-TURBINE SYSTEM” which uses multiple in-ground air-ducts with multiple wind-turbines. oo

A trench with a width of around three hundred (300) millimeters and a depth of approximately six hundred (600) millimeters is dug out from the surface of a road . and in the middle of a road lane such that the longitudinal axis of the trench is oo generally parallel to the longitudinal axis of the road.

A VAWT with a rotor ~~ diameter of about two hundred millimeters and a length of about ten metres is then installed inside the trench and connected to an electrical generator or hydraulic pump or pneumatic pump.

The top opening of the trench is then covered with a grille which. is mounted approximately flush to the road surface and which allows wind-drafts Co from motor vehicles passing overhead the trench to turn the wind-turbine inside the trench.

A drain is incorporated inside the trench to drain water to one end of the trench where at least one water pump is installed to pump the water out of the trench onto the road surface. :

BRIEF DESCRIPTION OF THE DRAWINGS : :

The advantages and objects of the present invention are summarized but not limited - to the following drawings, the full scope of which are embodied in the appended : claims of the present invention :- oo

FIG. 1a shows a sketch of the top-plan view a wind-turbine of the present invention : with a stack of three propellers. FIGs. 1b and 1c show the side elevation views of the same wind-turbine from two different directions.

FIGs. 2a and 2b show the cross-sectional views of an air-foil rotor blade in the same direction of rotation but under opposite wind directions. FIG. 2c shows a sketch of the top-plan view another wind-turbine of the present invention using the air-foil rotor blade as described in FIGs. 2a and 2b. SE

FIG. 3 shows a sketch of the side elevation view of another embodiment of a wind- ~ turbine under the present invention having a stack of four propellers (each shown : with only two rotor blades for clarity of the sketch). SE

FIGs. 4a and 4b show the side cross-sectional and top plan views respectively of another embodiment of a wind-turbine under the present invention installed inground : in a trench below a road surface. | | -

- DETAILED DESCRIPTION OF THE PRESENT INVENTION

FIG. 1a shows a sketch of the top-plan view a wind-turbine 1 of the present invention with a stack of three propellers 2, 3, 4, each having three rotor blades and mounted on top of each other, with propeller 2 at the top, propeller 3 in the middle oo and propeller 4 at the bottorh. The propeller hub 6 (shown only for propeller 2) of each propeller 2,3, 4 is centrally mounted ona rotor shaft § which is supported by : ) the stator frame 7. The rotor blades of the propellers 2, 3, 4 are offset at a horizontal angle from each other as viewed along the longitudinal axis of the rotor shaft 5. ~~ When the wind blows in the direction 10, the rotor of the wind-turbine 1 which consists of the rotor shaft § and propellers 2, 3, 4 rotate in the direction 9. Additional - air-vanes or wind-guides 8 are mounted on the stator frame 7 to direct air onto the. - propellers 2, 3, 4. The rotor of the wind-turbine 1 can be connected to a power conversion means (not shown) which can either be an electrical generator or a hydraulic or pneumatic pump connected to a hydraulic or pneumatic system respectively. An electrical generator can also be connected to the hydraulic or pneumatic system to generate electricity. | oo

The rotor blades of the propellers 2, 3, 4 can be of a similar design as that for the fan blade of an axial, diagonal or mixed-flow fan or turbine, and can be made from plastic or metal or a combination of plastic and metal materials. The length of the rotor blades of the propellers 2, 3, 4 can be as long as two meters long and as short as fifty millimeters, similar in size to those rotor blades used in computer cooling axial fans. An application of a rotor with such small blades is described in FIGs. 4a, 4b.

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FIGs. 1b and 1c show the side elevation views 13, 23 respectively of the same wind- turbine 1 of FIG.1a as seen from directions 11, 12 respectively in FIG.1a. In " FIG.1b, the rotor 14 is mounted on a rotor shaft 15 which is supported by. the stator frame 16. Each rotor blade 17, 18, 19 is inclined at an acute angle with respect to the stator frame 16 (facing against the direction of rotation 21).

As the wind blows in the direction 20, the rotor blades 17, 18, 19 act like wind- barriers and capture most of the wind in the direction 22, resulting in the rotor 14 rotating in the direction 21. Some wind will escape in the direction 23 in between the gaps of the rotor blades 17, 18, 19. :

In FIG.1c¢, the rotor blades 25, 26, 27 are similarly inclined against the direction of : rotation 29. As the rotor continues to rotate in the direction 29, the rotor blades 25, = 26, 27 deflect the wind moving in the direction 28 into the direction 30 and over each of the rotor blades 25, 26, 27, thereby reducing wind resistance on the rotor. blades 25, 26, 27.

FIGs. 2a and 2b show the cross-sectional views of an air-foil rotor blade 31, 38 respectively moving in the same direction of rotation 34, 39 respectively but under opposite wind directions 35, 40 respectively. Both air-foil blades 31, 38 have a convex leading edge 32 and a concave trailing edge 33 (marked in FIG. 2a only).

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In FIG.2a, as the air-foil rotor blade 31 rotates in the direction 34, wind coming in the direction 35 is deflected into the direction 36 above the air-foil rotor blade 31 and : into the direction 37 below the air-foil rotor blade 31. Due to the aerodynamic design of the air-foil rotor blade 31, the wind resistance is minimized and the air-foil rotor blade 31 experiences vertical aerodynamic lifts as well. :

In FIG.2b, as the air-foil rotor blade 38 rotates in the direction 39, wind coming in : the direction 40 is mostly captured by the concave shape of the trailing edge of air- oC foil rotor blade 38, resulting in the wind pushing air-foil rotor blade 38 in the direction 41 causing the air-foil rotor blade 38 to rotate in the direction 39.

FIG. 2c shows a sketch of the top-plan view another wind-turbine 42 of the present invention using the air-foil rotor blades 31, 38 described in FIGs. 2a and 2b. The : wind-turbine consist at least one propeller having rotor blades 43, 44, 45, 46 mounted centrally on the rotor shaft 51. Each of the rotor blades 43, 44, 45, 46 have the air-foil cross-section 47, 48, 49, 50 respectively as viewed along the longitudinal axis of each of the rotor blades 43, 44, 45, 46.

As the wind blows in the direction 52, the rotor blade 4S captures most of the wind in the direction 54 due to its concave trailing edge, pushing the rotor blade 45 forward and resulting in rotor blades 43, 44, 45, 46 rotating in the direction 53. Further, — of the wind moving in the direction 54 is directed into the direction 55 towards the outer radial edge of the rotor blade 45 and into the direction 56 towards the direction : 57, pushing the rotor blade 44 in the direction of rotation 53.

As the leading edge of blade 43 is convex, the wind blowing in the direction 52 is mainly deflected in the direction 58 with minimal wind resistance. In order to further - enhance the rotation of the rotor blades 43, 44, 45, 46, additional air-foils 59 can be attached to the tip of each rotor blade 43, 44, 45, 46. Such air-foils 59 can be of a similar design as that for a Darrieus wind-turbine. -

FIG. 3 shows a sketch of the side elevation view of another embodiment of a wind- turbine 60 under the present invention having a stack of four propellers ‘with oo propeller hubs 61, 62, 63, 64 and rotor blades 65, 66, 67, 68 respectively (only two "rotor blades per propeller are shown for clarity of the sketch). Propeller hubs 61, 62, 63, 64 are stacked on top of each other and mounted centrally on a rotor shaft 69 “which is mounted on a stator frame or a ground surface 74. The length of the rotor “blades 65, 66, 67, 68 can be as long as twenty metres and the rotor blades 65, 66, 67, 68 can be made from plastic or metal or a combination of plastic and metal materials. And the rotor shaft 69 can be as tall as thirty metres. This will equatetoa wind-swept area of one thousand and two hundred square meters. ~ Due to the size and weight of the rotor blades 65, 66, 67, 68 , the rotor blades 65, 66, 67, 68 can be linked physically together by vertical supports 70 which can then be supported on wheels 73 which roll along the stator frame or ground surface 74 to facilitate the rotation of the rotor of the wind-turbine 60. Also, the vertical supports ~ 70 can be further supported by stay-wires 71 which are mounted to the propeller hubs 61, 62, 63, 64. | oo a

Additional air-foils 75 can be mounted on the tips of the rotor blades 65, 66, 67, 68 to facilitate the rotation of the rotor blades 65, 66, 67, 68. Due to the aero-dynamic lifts experienced by the rotor blades 65, 66, 67, 68, the rotor blades 65, 66, 67, 68 tend to be lifted vertically during rotation. Therefore, hinges 72 can be installed for each rotor blade 65, 66, 67, 68 at their respective propeller hubs 61, 62, 63, 64 to -allow small vertical movements of the rotor blades 65, 66, 67, 68 along the longitudinal axis of the rotor shaft 69. So oo ~ FIG. 4a shows the side cross-sectional view of another embodiment of a wind- turbine 76 under the present invention installed inground in a trench 78 below a road ‘surface 79. The rotor 77 is similar to that described in FIGs. 1a, 1b, 1¢ above ~ whereby the diameter of the rotor 77 is smaller than three hundred millimetres and the length of the rotor 77 can be as long as ten metres. The rotor 77 is mounted on stator supports 81 and is connected to a generator 82 to produce electricity which can then be transmitted (not shown) outside the trench 78. A grille 80 is mounted over the top of the trench 78 and approximately flush with the road surface 79. A a miniature kerb (not shown) with a height of around fifteen millimetres from the road : 'suifane 79 can be built around the grille to minimise water ingress into the trench 78.

The trench 78 can be as wide as three hundred millimetres and as deep as six-hundred millimetres. The trench 78 has a water drain which slopes from the higher end 83 to the lower end 84 where at least one water pump 85 is installed to pump water ~ collected in the trench 78 out to the road surface 79 via a water outlet pipe 86.

Therefore the wind-turbine 76 can be installed inground on any road surface inclination as the water pump 85 will ensure that the trench 78 will not be flooded at “any time. The water pump 85 can be operated automatically from a battery source (not shown) which is charged by the electrical generator 82. "FIG. 4b shows the top plan view of the trenches 88, 89 whereby the wind-turbine 76 as described in FIG. 4a is installed (not shown). The trenches 88, 89 are installed in the middle of road lanes 90, 91 respectively. The width of the trenches 88, 89 can be oo made as small as two hundred millimeters which is smaller than the width of most tires of most motor vehicles. Therefore the drivers of the motor vehicles 92 will not

C7 feel any change in the road condition. = : ) As the motor vehicles 92 move in the direction 93 along the road lanes 90, 91, the wind drafts generated by the motor vehicles 92 force the wind-turbines (not shown) inside the trenches 88, 89 to rotate and generate electricity which can then be transmitted by underground cables (not shown) to a control and transmission panel 94 installed behind the road safety barrier 95.

In summary, it is possible through the present invention to create and install a new type of vertical-axis wind-turbine which combines the best characteristics of

Savonius and Darrieus wind-turbines. Also, the new vertical-axis can be made small - enough to be installed inground below a road surface or large enough to compete with large horizontal-axis wind-turbines in commegial wind-farms. oo

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The present invention will achieve the objects of the invention as stated above. The present invention does not contain any proprietary information or require any specialized skills to design and install. Any person skilled in the construction and engineering trades will be able to design and install the various embodiments of the . present invention without any problems using standard parts and equipment. :

Claims (6)

1. Lo | a7 B CLAIMS: | oo What is claimed is:- LA vertical-axis wind-turbine having a rotor with an axis of rotation generally perpendicular to direction of the wind, comprising:- | - oo : e a rotor shaft mounted rotatably on a stator frame oo e at least one propeller mounted centrally on the said rotor shaft to create the said rotor:- h » whereby any next said propeller is stacked on top of the first said propeller ’ i = and any additional said propeller is stacked on top of the first said . propeller and the next said propellers = such that each rotor blade of each said propeller can either be offset at a constant angle (as viewed along the. longitudinal axis of the said rotor) from the said rotor blade of an adjacent said propeller oo ~ oo - = or be aligned with the said rotor blade of an adjacent said propeller along the said longitudinal axis of the said rotor oo oo - ~~ ® and such that all said propellers rotate in unison with the rotation of the - said rotor shaft | | Co oo ~~" on a plane which is generally perpendicular to the said axis of rotation of oo the said rotor oo ~~~ e means to physically attach the said rotor shaft of the said wind-turbine to a. - power conversion means. | ; Co oo

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2. 2. The said wind-turbine in Claim 1 whereby each said propeller:- e comprises at least three said rotor blades, each said rotor blade having aradial disposition and a leading edge which is inclined with respect to the said longitudinal axis of the said rotor at an acute angle facing the direction of rotation of the said rotor blade:- - = whereby each said rotor blade can either be of a similar design as a rotor blade of an axial, a diagonal or a mixed-flow fan or turbine *= or be of a similar design as an airfoil with an approximately convex leading edge and a concave trailing edge EE : = and whereby each said rotor blade can be hinged at the hub of the said oo . propeller to allow movement of each said rotor blade along the said longitudinal axis.of the said rotor | | : : : = and whereby each said rotor blade can be supported by stay wires fixed to the said rotor shaft of the said propeller ) e can be physically linked to the next said propeller to facilitate the tandem rotation of all said propellers:- ~ | oo = and whereby all said propellers can be supported by rollers linked to the said stator frame | - oo e can have additional airfoils attached to each said propeller.
3. 3. The said wind-turbine in Claim 2 whereby air-vanes and air-guides can be incorporated around the circumference of the said stator frame to direct wind . | onto the said rotor.

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4. 4. The said wind-turbine in Claim 2 whereby the said power conversion means can include an electrical generator, a hydraulic pump, pneumatic pump and associated control, regulation and transmission means to generate and transmit electricity, hydraulic or pneumatic power. oo
5. 5. The said wind-turbine in Claim 2 whereby the said rotor of the said wind- turbine can be installed in a vertical, horizontal or inclined position. So
6. 6. A method of installing the said wind-turbine in Claim 4 below a road surface to capture the wind-drafts from motor vehicles moving overhead whereby:- e the said rotor is installed inside a trench which is dug out from the said road surface such that:- | a. Co | oo = the longitudinal axis of the said trench is generally parallel to the longitudinal axis of the said road surface oo = a grille is installed over the top opening of the said trench and mounted : approximately flush with the said road surface E o such that the said rotor is in constant pneumatic communication with oo oo © the air above the said road surface oo = awater drain is incorporated inside the trench to drain water to one end of the said trench - | oo o whereby at least one water pump is installed at the said end of the said CS i ~ trench to pump said water out of the said trench eo the diameter of the said rotor of the said wind-turbine is less than three hundred (300) millimetres.