A savonius type wind turbine

Abstract

The invention is related to a Savonius type wind turbine that harvests wind flow and a power generator is driven by the Savonius type wind turbine to produce electricity.

Description

[0001] A SAVONIUS TYPE WIND TURBINE

[0002] Technical Field

[0003] The invention is related to a Savonius type wind turbine that harvests wind flow and a power generator is driven by the Savonius type wind turbine to produce electricity.

[0004] Prior Art

[0005] Sustained use of fossil fuels in a wide range of applications is widely viewed as a principal - but not the only - cause of so-called global warming. Matching the increasing climatic disasters associated with global warming there is an increasing demand for sustainable energy production achieved through wind and solar energy sources.

[0006] Solar applications through photovoltaics have seen major deployments of ‘solar energy farms’ in different forms across the entire world - despite a typically low power coefficient, Cp, of less than 20%. The wide acceptance of solar power can be seen in contrast to the very limited acceptance of on-shore wind-turbine devices, despite a typical Cpof 25-30%, able to operate 24 / 7 - operation not being restricted to daylight hours.

[0007] Very large off-shore wind turbines, known as Horizontal Axis Wind Turbines, HAWTS, with a higher Cpgreater than 50%, are extensively deployed around many coastlines and high altitude agriculture are of Europe (in particular) but despite the higher Cpthere are marked environmental disadvantages to HAWTS, recently leading to noticeable demands for the dismantling of some of these HAWTS in countries such as Scandinavia.

[0008] Amongst the more obvious disadvantages of HAWTs is the relatively high levels of sound pollution (making them impossible to deploy except in remote areas), unsightly visual pollution, as well as maintenance issues because the generator is perched on top of a large tower typically accessible only by helicopter. Also, the fracturing of these massive fiberglass blades results in the surrounding agricultural land becoming unusable because minute shards of fiberglass are scattered around the breakage

[0009] A Savonius type which is type of the vertical axis wind turbines (VAWTs) are known as a quieter turbine option than HAWTs. However, the Savonius type VAWTs’ power coefficient (<30%) is much lower than HAWTs and which has resulted in less scientific investigation about utilisation of Savonius type VAWTS.

[0010] As can be seen in Figure 4, the Savonius type VAWTs comprises two blades (number of the blade can be increased), whereby one blade is concave in shape - otherwise known as the advancing blade - and the other blade is convex in shape - otherwise known as the retreating blade. The two blades are positioned opposite each other and affixed to a central shaft. When wind pressure activates the advancing / concave blade it pivots or rotates around the axis of the central shaft, as torque is transferred to an electric generator at the lower end of the shaft.

[0011] The problem that lowers power coefficient of the Savonius type VAWTs is the retreating / convex blade which is subjected to the same wind pressure, resulting in drag thereby negating efficiency of the wind pressure on the advancing / concave blade.

[0012] There are studies that propose deformable blades utilizing elastomers to solve addressed problem in known state of art. That deformable blades deform to reduce negative drag. However, deformable materials tend to have limited life cycle.

[0013] The foldable blades are another alternative for increasing the power coefficient for VAWTs.

[0014] US2017107972A1 discloses a vertical wind turbine. The vertical wind turbine is provided with a rotating vane housing mounted between an upper, cam disk and a lower, base disk, the base disk being mounted to a shaft. A plurality of turbine blades are pivotally mounted around the vane housing, each of the blades being pivotal between open and closed positions with respect to the housing. The cam disk defines a cam profile. A roller follower is coupled to each turbine blade. The follower forces the connected blade to open or close as the follower travels along the cam profile during each revolution of the housing. The open position of the blade harnesses wind energy to induce torque for rotating the housing. The closed position of the blade reduces drag to increase efficiency of the vertical wind turbine.

[0015] Amiri et al. discloses a study (“Experimental and numerical investigations on the aerodynamic performance of a pivoted Savonius wind turbine” (2016). Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy. 231. 10.1177 / 0957650916677428) for aerodynamic performance of Savonius wind turbines. The Savonius wind turbines described in this study features concave blades connected around the rotor in a pivotal manner. Depending on the direction of the incoming wind, the blades close onto the rotor to minimize wind intake or open in the opposite direction to maximize wind intake.

[0016] WO2011022835A1 discloses a fluid turbine. This fluid turbine comprising a stator having a track, a floating rotor rotatable upon an axis and a plurality of paddles, each paddle pivotally coupled to the rotor at a first end and coupled to the track at a second end. The floating position of the rotor enables movement of its axis versus the stator's axis which changes the eccentricity of the paddles relative to the track thereby increasing exposed surface area of the paddles on one side of the axis while decreasing it on the opposing side and that reduces efficiency

[0017] CN104595104A discloses a vertical shaft fan impeller. When the impeller is under the effect of wind, a connecting vane and a tail end vane in the flexible vanes can rotate around a hinge, under limiting of a rotating clamping groove, full stretching is achieved at a windward face, an arc face is formed at an against-wind face, and accordingly resistance is lowered and reduces efficiency.

[0018] These mentioned studies lessen negative of effect of the drag force on blades of Savonius type VAWTs. However, they cause shaft or axle on VAWTS is subject to long-term, high, negative stresses because of the variable load conditions under each rotation that ultimately leads to destructive vibration.

[0019] As a result, all of the problem mentioned above has made it necessary to provide a novelty in the related field.

[0020] Brief Description and Objects of the Invention

[0021] The main object of the present invention is to establish a Savonius type wind turbine design that enhances power coefficient while reducing effect of destructive vibration.

[0022] Another object of the present invention is to enable use of rigid blades in Savonius type wind turbine designs that addresses low power coefficient issue.

[0023] To accomplished that, Savonius type wind turbine comprise at least one centerpiece fixedly connected to a main shaft that rotatable on a main axis, at least two Savonius type blade connected to the centerpiece in a pivotally rotatable manner on a secondary axis which is parallel to the main axis, at least one guide plate having a circular channel, a guide connected to the blade and positioned on the circular channel in such way that the guide movable on the circular channel. Here, while folding Savonius type blades enhances power coefficient folding the movement of the Savonius type blade is guided by a guide, such as a wheel, that follows a circular channel formed on guide plate and that movement controlled by the guide and the circular channel significantly reduces vibration greatly.

[0024] Such low efficiency leaves opportunities to improve the design of Savonius type VAWTs by optimizing the main characteristic parameters or blade shape. Simulation results show a strong capability for enhancement, taking the current Cp of a Savonius type wind turbine of <30% increasing to >40%. This marked improvement in the Cp radically alters the calculation of the Levelised Cost of Energy (LCoE), suggesting such an optimized wind turbine would become much more feasible applied in an urban area.

[0025] Description of the Figures of the Invention

[0026] The figures and related descriptions necessary for the subject matter of the invention to be understood better are given below.

[0027] Figure 1. A side elevation view of the present invention.

[0028] Figure la. A top view of the centerpiece on the shaft, the blades and the guide plate.

[0029] Figure 2. A top view of the centerpiece on the shaft, the blades and the guide plate in different positions.

[0030] Figure 3. A side elevation view of an alternative embodiment of the present invention

[0031] Figure 4. A schematic view of Savonius type wind turbine in state of known art.

[0032] Reference Numbers

[0033] The parts and components are given in the figures are referenced for the subject matter of the invention to be understood better.

[0034] 1. Turbine

[0035] 10. Centerpiece

[0036] 20. Blade

[0037] 21. Guide

[0038] 22. Hinge

[0039] 23. Trailing edge 30. Guide plate

[0040] 31. Channel

[0041] 40. Weather Protective Dome

[0042] 50. Generator Housing

[0043] S. Shaft

[0044] Rl. Main axis

[0045] R2. Secondary axis

[0046] Detailed Description of the Invention

[0047] The invention is related to a Savonius type wind turbine that harvest wind flow and a power generator is driven by the Savonius type wind turbine to generate power.

[0048] Referring to Figure 1; A Savonius type wind turbine (1) comprises main shaft (S) (not shown in Fig. l), a centerpiece (10) with blades (20), a guide plate (30) with channel and a guide (21) for the blades (20).

[0049] The main shaft (S) of the Savonius type wind turbine (1) is configured to transfer harvested wind energy to the power generator (not shown) directly or indirectly. The main shaft (S) is rotatably in a main axis (Rl) and vertically provided on the wind turbine (1). Preferably, the main shaft (S) is positioned between generator housing (50) which protects the electrical components and weather Protective Dome (40).

[0050] The centerpiece (10) fixedly connected to the main shaft (S) and transfers torque from the blades (20) to the main shaft (S), thereby activating rotation. The main shaft (S) preferably goes through the centerpiece and they can rotate together. The centerpiece (10) extends in direction of main shaft (S).

[0051] At least two blades (20) are connected to the centerpiece (10). Connection between is pivotally provided. The edge of the blades (20) that connects the centerpiece can rotate in secondary axis (R2) wherein the secondary axis (R2) is parallel to the main axis (Rl). The blades (20) are fitted each side of the centerpiece (10) such that allowing the blades to move backwards and forwards, opening and partially closing, according the position of the blade (20) in rotation around the axis. The embodiment having only two blades (20) is more efficient than the embodiment having three or more blades.

[0052] Preferably, the pivotally rotatable connections are provided by the hinges (22). The hinge (22) may be provided by section extending from both parts to each other and entering between opposite sections and a pin passing through these parts. Alternatively, a known hinge (22) in state of the art can be used.

[0053] The blades (20) are Savonius type blades (20). The Savonius type blades (20) comprises at least one convex and one concave blade. These blades (20) function as advancing blade and retreating blade because according position of them and wind direction. Advancing blade (20) refers to the blade (20) under positive wind pressure and retreating blade (20) refers to the blade (20) under negative wind pressure. The combination of two blades (20) may resemble “S” shape.

[0054] In a preferred embodiment, the blades (20) are made of rigid material such as metal.

[0055] In a preferred embodiment, the guide plate (30) also in curved parts that extends to the blades (10) and as can be seen in Fig. la curvature of these curved parts and curvature of the blades (10) that the curved part is connected is equal so the center piece (10) matches the aerodynamics of the surfaces of blades.

[0056] In a preferred embodiment, a trailing edge (23) is provided tip of the blades (20) and is parallel to the fluid forces for the specific reducing suction vertices / specific vortex drag. The so-called trailing edge acts in a similar manner to winglets at the wing tip of many aircraft. Purpose of the trailing edge and winglets is to reduce turbulence created when air (fluid) passing over two separate surfaces converge at a point or location where the two airflows meet, creating turbulence (and, thereby, some suction vertices).

[0057] On top or bottom of the main shaft (S), the guide plate (30) is positioned. Preferably, the guide plate (30) is positioned bottom of the main shaft (S). The guide plate (30) is fixed. That means the guide plate (30) doesn’t rotate with the main shaft (S). Preferably, the guide plate (30) is planar plate.

[0058] The channel (31) formed on the guide plate (30), The channel (31) is circular and provided coaxially with the main shaft (S) to correspond to movement of the blades (10). Each blade (20) comprises a guide (21) that positioned into the channel (31) and the guide can move along the channel (31) to decrease or eliminate the vibration of blades (10) by controlling rotational movement and the folding action. The channel (31) may be provided as a slot.

[0059] In a preferred embodiment, a guide (21) is a wheel to provide more stable movement on the channel and this also reduces vibration.

[0060] Referring to Fig. 2; the straight arrows in Fig. 2 refers the wind direction. The contact of the wind on convex side of the blade (10) rotates the blade (10) around the secondary axis (R2) and moves it to closed or partly closed position to reduce the wind contact. The contact of the wind on concave side of the blade (10) rotates the blade (10) around the secondary axis (R2), too and moves it to fully or partly open position to increase the wind contact.

[0061] Referring to Fig 3; the wind turbine (1) of the present invention may comprise two or centerpiece (10) with mentioned blades (20) on a same main shaft (S) to improve harvesting wind amount. To achieve such an improvement, a guide plate (30) must be positioned for each one of centerpiece (10).

[0062] The Savonius type wind turbine (1) of the invention can be used with a power generating system. The power generating system comprises at least one power generator to convert harvested wind by the wind turbine (1) to power. For this, the output of the main shaft is directly or indirectly transfer to input of the power generator.

[0063] It should be noted that dimensions of these wind turbines are not described here, nor is the power output nominated. A typical Savonius type wind turbine has a typically in hundreds of Watts, whereas this WT claims outputs measured in KWs.

Claims

CLAIMS1. A Savonius type wind turbine (1), characterized byAt least one centerpiece (10) fixedly connected to a main shaft (S) that rotatable on a main axis (Rl),At least two Savonius type blade (10) connected to the centerpiece (10) in a pivotally rotatable manner on a secondary axis (R2),At least one guide plate (30) having a circular channel (31),A guide (21) connected to the blade (10) and positioned on the circular channel (31) in such way that the guide movable on the circular channel (31).

2. A wind turbine (1) according to Claim 1, wherein the centerpiece (10) extends in direction of the length of main shaft (S).

3. A wind turbine (1) according to Claim 1 or 2, wherein the centerpiece (10) comprises curved parts that extends to the blades (20).

4. A wind turbine (1) according to Claim 3, wherein the curvature of curved parts and curvature of the blades that the curved part is connected is equal.

5. A wind turbine (1) according to Claim 1 or 4, wherein one of the Savonius type blade (20) is concave shaped and one of the Savonius type blade (20) is convex shaped.

6. A wind turbine (1) mechanism according to Claim 1, wherein the blades (10) are made of rigid material.

7. A wind turbine (1) mechanism according to Claim 6, wherein the blades (10) are made of metal.

8. A wind turbine (1) mechanism according to Claim 7, wherein the blades (10) are made of aluminium.

9. A wind turbine (1) mechanism according to Claim 6, wherein the blades (10) are made of fiberglass or carbon fibre.

10. A wind turbine (1) according to Claim 1, wherein the guides (21) are wheels.

11. A wind turbine (1) according to Claim 1, characterized by hinges (22) connects the Savonius type blades (20) to the centerpiece (10) in a pivotally rotatable manner.

12. A wind turbine (1) according to Claim 1, characterized by further comprising a trailing edge (23) provided tip of the blades (20) and is parallel to the fluid forces for the specific reducing suction vertices.

13. A wind turbine (1) according to Claim 1, characterized by comprises at least centerpieces (10) connected to same main shaft (S) and a guide plate (30) for each one centerpiece (10).

14. A power generating system, characterized byA power generator andA wind turbine (1) according to any preceding claims and connected to the power generator in such a way that the main shaft (S) drives the power generator to generate power.

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