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| ==Introduction== | | =Content moved to [http://wiki.opensourceecology.de/Wind_Turbine Open Source Ecology Germany].= |
| We are developing an open source wind turbine with an agile open collaboration.
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| [[TiVA]] and [[Germany/Wind_Turbine|wind turbine]] specifications started with a joint development venture between [http://www.etemu.com etemu.com] and [http://apollo.open-resource.org Apollo-NG]. All information is released open source and for free, for a better world and for the fun of open collaboration. (CC BY-SA)
| | ==Status== |
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| ==[[TiVA]]==
| | The '''wind turbine''' is in the research phase of product development, we are focusing on the '''[[TiVA]]'''-System right now. |
| Research and development is currently concentrated onto [[TiVA]], a tiny wind turbine prototyping platform. With this very small turbine, we can easily change parts, try out new ideas and increase the quality of the design on a small scale in a fast and inexpensive way. Please have a look at the [[TiVA]] page for further information.
| | [[File:Etemu.com_TiVA_l2_front_wip.jpg|720px|thumb|center|3D Model of a [[TiVA]] rotor, work in progress. Note the hollow wings, this is a hybrid lift/drag wing profile with a full load TSR<ref>Tip Speed Ratio</ref> of 0.85.]] |
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| ==Team==
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| If you want to participate add your name and how you want to participate here, also please introduce yourself in the [[Germany/Communication#Google_Group|Google Group]].
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| * [[Alex Shure]] – research and development
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| * [[chrono]] -
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| * [[Nikolay Georgiev]] - communication and organization
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| ==Roadmap / Log== | | ==Sources== |
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| * 20120211 [[Alex Shure]] Start of "Open Agile SCRUM GVCS machine development" mailing list, [[Nikolay Georgiev]] sent an E-Mail to some OSE:E members - We begin to discuss the OSE:E project of constructing a wind turbine
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| * 20120222 [[Alex Shure]] First online meeting on the OSE:E project "develop a wind turbine" in mumble
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| * 20120311 [[Alex Shure]] I had a 6 hour meeting with a German wind turbine technician who works in QS where we discussed various aspects, advantages and disadvantages of horizontal and vertical axis wind turbines.
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| * 20120324 [[Alex Shure]] Had an online conference in mumble and spoke with [http://opensourceecology.org/wiki/Special:Contributions/Chrono Chrono], founder of the [[Apollo-NG]][https://apollo.open-resource.org] project. Chrono has experience in electronics, especially in integrated low power switching power supplies and mobile energy supplies. He is transforming a van into a mobile hackerspace, powered by renewable energy, totally off the grid.
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| * 20120325 [[Alex Shure]] Phone conference with Detlef Schmitz from the solar car team Heliodet; Detlef offered to build one small wind turbine prototype. He has contacts also with engineers and technicians form the solar car project, especially students from the FH/uni in Bochum.
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| * 20120326 [[Alex Shure]] Added the EVA wind turbine design. We could develop a VAWT which can be optionally equipped with the EVAwt features. The biggest disadvantage is the design issue with the top cover plate: with the EVAwt design, I can't think of an easy way to span the cables from the top for now.
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| * 20120327 [[Alex Shure]] [[chrono]] added a pad on Apollo for collaboration
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| * 20120328 [[Alex Shure]] Calculations
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| * 20120329 [[Alex Shure]] contacted Bernd from http://www.daswindrad.de
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| * 20120330 [[Alex Shure]] Added the [[TiVA]] idea
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| * 20120331 [[Alex Shure]] [[chrono]] moved the content from the pad at Apollo-NG into the dokuwiki at Apollo-NG. I split the [[TiVA]] parts and copied them to a wiki page here at [[OSE]]
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| ==General design outlines==
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| The wind turbine should be loosely designed according to the [[OSE Core Values]] except points 8 and 9, which demand high performance and equal to or higher than industrial efficiency <ref>[[OSE Core Values]] points 8 and 9 demand a high performance and equal to or higher than industrial efficiency but the efficiency of a highly sophisticated industrial, FEA designed and airflow-simulated, wind tunnel tested model can't be matched by a diy design.</ref>
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| In addition to the [[OSE Core Values]], the wind turbine should be safe to operate, e.g. have a suitable safety factor in all structural calculations, proper isolation to prevent an electric shock.
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| We want to design a rather small VAWT, resulting in the following advantages:
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| * + DIY! People should be able to build them! -> KISS principle
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| * + less moving parts
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| * + does not necessarily have to be elevated, can stand on the ground
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| * + collects wind from every direction: no need for a directional control (+less mechanics, electronics)
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| * + has a smaller footprint
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| * + easier to design
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| * + way more easy to build
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| * + does not need a variable pitch control for high wind speed/ high power designs
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| * + uses cheaper materials, less bearings and axles, less machining operations
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| * + maintenance is easier, as the generator is on the ground, no need for a lift or a breakdown of the turbine head
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| * + a modular design is possible in a certain range (e.g. building it higher/longer in any direction)
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| * + does not necessarily need moldings or 3D shapes like sophisticated VAWT turbine blades
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| * - lower rpm at the same rotor diameter, at the same wind surface area due to the partly reversed draft of the wings but:
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| * + can have a small diameter but a rather large height, thus more torque ''and'' more rpm
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| Main disadvantage against a horizontal axis wind turbine:
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| * - less power output compared to a sophisticated HAWT design if wind direction does not change often and turbulence is low
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| The small form factor alone yields the following advantages next to being diy-friendly:
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| * + easier maintenance
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| * + mobility, less weight
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| * + smaller impact on the environment/nature
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| * + lower system voltage and lower currents, less risky to operate
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| * + a smaller power rating results in a less complicated generator and inverter design
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| * + batteries can be charged quick&dirty with a simple charging circuit from a small wind turbine, which would not be possible with a high power wind turbine
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| Specialties about distributed energy sourcing with small wind turbines:
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| * (tbd) Multiple smaller wind turbines may have more physical weight per sourced energy (kg/kW) versus one large one.
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| * - requires an additional electrical infrastructure between multiple smaller wind turbines versus one large one -> more cables and balancing (electronics)
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| * + the grid can be laid out in such a way, that the turbines can be placed where the energy is needed the most, resulting in smaller run lengths of power cables and less power losses.
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| * + the small turbines can easily be moved to an area with a higher wind speed. This is interesting when it comes to structural or seasonal changes of the wind, e.g. when the trees grow leaves and form a barrier which decreases the ground wind speed or they form an alley/a tunnel which increases the wind speed, one may move the wind turbine to gain from the new environment.
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| Simply said, it is more flexible to use many small turbines versus one large one. If a larger energy source is required, we connect multiple wind turbines in a local grid -> distributed energy sourcing, a 'wind farm' consisting of VAWTs:
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| [[File:flowe.jpg|thumb|alt=A VAWT testing space|The ''Caltech Field Laboratory for Optimized Wind Energy'' where arrays of closely spaced ''vertical axis wind turbines'' were tested.]]
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| <blockquote>Dabiri carried out field tests in the summer of 2010 at an experimental farm known as the Field Laboratory for Optimized Wind Energy (FLOWE), which houses 24 10-meter-tall, 1.2-meter-wide VAWTs. In the field tests, which used six VAWTs, Dabiri and his colleagues measured the rotational speed and power generated by each of the turbines when placed in a number of different configurations. One turbine was kept in a fixed position for every configuration, while the others were on portable footings that allowed them to be shifted around.
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| They found that the aerodynamic interference between neighboring turbines was completely eliminated when all the turbines in an array were spaced four turbine diameters (roughly five meters or 16 feet) apart. In comparison, propeller-style HAWTs would need to be spaced 20 rotor diameters apart - which equates to a distance of more than one mile for the largest wind turbines currently in use - for the aerodynamic interference to be eliminated.
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| The six VAWTs generated from 21 to 47 watts of power per square meter of land area, while a comparably sized HAWT farm generates just two to three watts per square meter.<ref>http://www.gizmag.com/optimizing-wind-turbine-placement/19217/</ref></blockquote>
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| ==How does the wind turbine generate energy?==
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| The energy is in the wind due to it's speed/local pressure differences. A wind turbine ''converts'' kinetic energy from the wind into mechanical energy. The VAWT yields energy as kinetic energy from the wind is absorbed by rotating wings.
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| {{Wide image-noborder|ETEMUcom_EVAwt6_iso.jpg|1280px|3=A sketched 3D ISO view of a simplified VAWT wind energy diagram. Full size view recommended. Note: Pictured is a drag-only rotor, but our intention is to design a lift-rotor, as it has a higher tip speed ratio and revolves faster.|4=99%|alt=A sketched 3D ISO view of a simplified VAWT wind energy diagram. Full size view recommended. Note: Pictured is a drag-only rotor, but our intention is to design a lift-rotor, as it has a higher tip speed ratio and revolves faster.}}
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| ==EVA wind turbine==
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| [[File:ETEMUcom_EVAwt8_intake_top_iso.jpg|thumb|Example of an '''''EVA''' wind turbine'' design, ISO view of the top end. Note the wing at the front and the tail rudder.<ref>http://etemu.com/p/evawt/ETEMUcom_EVAwt6_iso.jpg</ref>]]
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| The '''''E'''nhanced '''V'''ertical '''A'''xis Wind Turbine'' idea incorporates an intake manifold at the front which is always facing the direction where the strongest wind is coming from. The main disadvantage of the VAWT against a HAWT is reduced: There is no attacking wind which will work against the natural, clockwise rotation of the VAWT. This may result in an increased overall efficiency.
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| * + No wind is working 'against' the turbine, contrary to a standard VAWT, where half of the turbine is exposed to wind which flows into the 'wrong' direction
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| * + The wind speed right at the turbine intake is increased <ref>The deflection at the front adds up two "surfaces" of wind. However, the resulting wind speed won't change drastically.</ref>
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| * + (tbd) less oscillating forces, the wind flow is about unidirectional at the turbine: less vibrations and less wear at the rotating parts, more static and less dynamic thrust at the bearings, less torque ripple and cyclical stress.
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| * - More material is used for the construction of an '''''EVA''' wt'': two bearings, arms and static wings. However, these additional parts are not difficult to create, as the surfaces are all plan
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| Who can help with FEA + fluid dynamics and simulate the wind flow at various EVA wind turbine designs? We want to investigate what wing form the intake should have and at which angle it should be mounted. Also:
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| Does it increase the efficiency if there's another, longer planar surface at the right of the intake parallel to the wind direction (The position where only a short, structural surface is shown in the sketches)
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| <gallery>
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| File:ETEMUcom_EVAwt7_top_detailed_diagramm.jpg|Normal airflow in a VAWT at the maximum torque moment. Note the non-uniform airflow with varying surfaces as the turbine blades advance.<ref>http://etemu.com/p/evawt/ETEMUcom_EVAwt7_top_detailed_diagramm.jpg</ref>
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| File:ETEMUcom_EVAwt8_intake.jpg|Airflow in the '''''EVA''' wt'' design. View from the top.<ref>http://etemu.com/p/evawt/ETEMUcom_EVAwt8_intake.jpg</ref>
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| File:ETEMUcom_EVAwt8_intake_top_iso.jpg|Example of a simple constructional integration of the '''''EVA''' wt'' design with sheet material. ISO-View from the top.<ref>http://etemu.com/p/evawt/ETEMUcom_EVAwt8_intake_top_iso.jpg</ref>
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| </gallery>
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| =Calculations and Simulations=
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| All calculations are made in the ''metric'' system. Corrections and additional approaches are always welcome.
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| Let's start with the base mount.
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| As the design outlines state we won't start with a turbine greater than 4 m² due to restrictions in Europe pointed out by Detlef Schmitz. A wind surface of 4 m² equals a 2 m diameter rotor with a height of 2 m.
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| :<m>F_{pole} = \frac{1}{2} \times \rho \times C_d \times A_{wind} \times v_{wind}^2</m>
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| <m>\rho</m> = Density of air = about 1.2 Kg/m³ <br />
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| <m>C_d</m> = Coefficient of drag = 1.0 (cylinder Re > 100) <br />
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| <m>A_{wind}</m> = Area of turbine = 4 m² <br />
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| <m>v_{wind}</m> = Wind speed in m/s | |
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| (insert proper values here and calculate the displacement of the pole at high loads. Consider serious safety factor for robustness and against oscillations.)
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| Maximum wind speed the turbine has to withstand:
| | [[Category: Wind energy]] |
| {|
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| |IEC wind class
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| |I
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| |II
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| |III
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| |IV
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| |----
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| |50-year-maximum
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| |50 m/s
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| |42,5 m/s
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| |37,5 m/s
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| |30 m/s
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| |----
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| |average wind speed
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| |10 m/s
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| |8,5 m/s
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| |7,5 m/s
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| |6 m/s
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| |----
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| |}
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| ==Estimating the power output of the VAWT==
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| =====Power available in the wind:=====
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| :<m>P_{wind} = \frac{1}{2} \times \rho \times A_{wind} \times v_{wind}^3</m>
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| <m>P_{wind}</m> is the power, which is available in the wind. It is available as kinetic energy due to the moving mass of the air.<br />
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| <m>\rho</m> = Density of air = about 1.2 Kg/m³ <br />
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| <m>A_{wind}</m> = Area of turbine = max 4 m² at a small scale turbine <br />
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| <m>v_{wind}</m> = Wind speed in m/s <br />
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| =====Power available from the turbine:=====
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| This is the estimated ''mechanical'' wind power conversion.
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| :<m>P_{mech}=P_{wind} \times \rho_{turbine} </m>
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| while <br \>
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| <m>
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| \rho_{simple} = 20% \\
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| \rho_{decent} = 30% \\
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| \rho_{good} = 30% \\
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| \rho_{superbVAWT} = 40% \\
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| \rho_{superbHAWT} = 50%
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| </m><br \>
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| A tuned VAWT may have a best-case efficiency of 40%<ref>Can the EVAwt design yield more? Tbd!</ref>, while a simple drag-based turbine with no optimization nor special aerodynamics may have an efficiency of about 20%.
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| ==Other links==
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| * [http://www.rhein-zeitung.de/regionales/neuwied_artikel,-Energiemarkt-Frischer-Wind-weht-aus-Asbach-_arid,247585.html non OS example 1]
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| * http://www.fundamentalform.com/html/involute_wind_turbine.html
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| * http://www.daswindrad.de/forum/viewtopic.php?f=2&t=21
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| * http://www.tinytechindia.com/windenergy.htm
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| ====Daniel====
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| * http://www.youtube.com/user/danielturbin/videos?sort=dd&view=0 Wind is only one of many nice things he did
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| * http://www.maskinisten.net/viewtopic.php?t=8655 Forum with pictures and tests explained in Swedish
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| ==Sources==
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| <references />
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