Wind Turbine/en

We want to develop an open source wind turbine with an agile open collaboration.

Team

If you want to participate add your name and how you want to participate here, also please introduce yourself in the Google Group.

• Alex Shure – research and development
• Nikolay Georgiev - communication and organization

Roadmap / Log

• 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
• 20120222 Alex Shure First online meeting on the OSE:E project "develop a wind turbine" in mumble
• 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.
• 20120324 Alex Shure Had an online conference in mumble and spoke with Chrono, founder of the Apollo-NG[1] 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.
• 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.

Requirements

The wind turbine should be designed according to the OSE Core Values except points 8 and 9, which demand high performance and equal to or higher than industrial efficiency

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.

Design outlines

We want to design a rather small VAWT, resulting in the following advantages:

• + DIY! People should be able to build them! -> KISS principle
• + less moving parts
• + does not necessarily have to be elevated, can stand on the ground
• + collects wind from every direction: no need for a directional control (+less mechanics, electronics)
• + has a smaller footprint
• + easier to design
• + way more easy to build
• + does not need a variable pitch control for high wind speed/ high power designs
• + uses cheaper materials, less bearings and axles, less machining operations
• + maintenance is easier, as the generator is on the ground, no need for a lift or a breakdown of the turbine head
• + a modular design is possible in a certain range (e.g. building it higher/longer in any direction)
• + does not necessarily need moldings or 3D shapes like sophisticated VAWT turbine blades

• - lower rpm at the same rotor diameter, at the same wind surface area due to the partly reversed draft of the wings but:
• + can have a small diameter but a rather large height, thus more torque and more rpm

Main disadvantage against a horizontal axis wind turbine:

• - less power output compared to a sophisticated HAWT design if wind direction does not change often and turbulence is low

The small form factor alone yields the following advantages next to being diy-friendly:

• + easier maintenance
• + mobility, less weight
• + smaller impact on the environment/nature
• + lower system voltage and lower currents, less risky to operate
• + a smaller power rating results in a less complicated generator and inverter design
• + 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

Specialties about distributed energy sourcing with small wind turbines:

• (tbd) Multiple smaller wind turbines may have more physical weight per sourced energy (kg/kW) versus one large one.
• - requires an additional electrical infrastructure between multiple smaller wind turbines versus one large one -> more cables and balancing (electronics)
• + 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.
• + 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.

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:

The Caltech Field Laboratory for Optimized Wind Energy where arrays of closely spaced vertical axis wind turbines were tested.

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. 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. 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.

Other links

• non OS example 1
• http://www.fundamentalform.com/html/involute_wind_turbine.html
• http://www.daswindrad.de/forum/viewtopic.php?f=2&t=21
• http://www.tinytechindia.com/windenergy.htm