Demotech, design for self reliance

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WindDrive: The WindDrive ask for your imagination ...

The WindDrive ask for your imagination ...

Sorry! This concept text should be editted soon.

Imagine: You live in the wide plains of Argentina, Siberia or Namibia. If your electricity is delivered by a Honda generator, you may be confronted with one or more of the following difficulties:

  • The generator wears out, spare parts may not be available.
  • You have run out of petrol.
  • Petrol or gas oil may have become too costly for your budget

Are you interested in an alternative source of electricity?
Basically we are looking for a system:

  • Low-cost, available for poor people,
  • Locally made and to be repaired without delay, no dependance on import of spare parts. With the aid of Demotech instruction, local abilities should be sufficient for building.
  • Limited energy use for reading, radio computer, video. In general educational use. This excludes use of electricity for cooking, heating, production machinery, airco's. We consider ??? Watt/hours per day. Demotech has taken this need to heart. We considered an innovative way of using wind energy. We designed the WindDrive and offer you to participate in the development of this design by:
  • Testing the scheme by building a system;
  • Adding research information to the plan. Demotech takes care of embedding your new input into the master design.

    The WindDrive, innovative to which extend?
    The WindDrive is constructed from six innovative sub-designs:
    - From wind force to rotation; the WindRotor;
    - From rotation to electricity; the HighRev Generator, an highly efficient high tech devise;
    - From generator to energy storage; the one cell battery;
    - To optimize storage; a digital device for controlling in-going and out-going current.

    The successful spread of the Demotech RopePump is based on a method of 'marketing', now to be applied to the WindDrive. The future user is offered a video-manual, preferably in the local language, based on examples in similar conditions of use. More often the information spreads by mouth on mouth communication. People copy successful first users.
    Demotech stimulates autonomous copying and feed back to her Open Source website.

    Technical Explanation of the Wind-drive
    The wind-drive is built using local (waste) material, such as wood, iron-wire, sheet-metal, rubber and fabric to make the sails.
    Some special features of the Wind-drive:

  • The WindRotor is constructed very much like the frame of an umbrella.
  • The fork that carries the WindRotor: The fork is composed of thin sticks that can bend with the wind like the branches of a tree. When the direction of the wind changes, the wind pressure on the wheel causes the fork to turn around its axis, thus ensuring that the Wind-drive is always facing the wind.
  • The sails: Inside the WindRotor there is ample space for attaching sails. There is no need for high efficiency air-foils, as any simple set-up of sails delivers enough torque to run the generator. On the other hand, a smart make up of the sails may help to reduce hazards of sudden wind blasts and can facilitate an even rpm.
  • The weather vane: The hinge: allows horizontal rotation and enables the drive to be inclined horizontally for maintenance

    It consists of the following parts:

  • The wheel, made of bamboo segments;
  • Spokes, made of iron-wire;
  • Rope-gliding forks, made of iron-wire;
  • Sails, made of any material available;
  • Rope, the essential part between drive and dynamo;
  • The generator
  • The frame that carries the WindRotor and the generator, but that can turn with the wind direction.
  • A battery, according to a new Demotech design.

    The rope
    THE rope is an old-fashioned way to transmit power. It ha been banned from the schoolbooks as primitive and ugly, which is the reason why nobody came up with the idea of using rope. Rope fits in perfectly with the WindDrive project. It is available anywhere, at little cost. Most importantly, its great flexibility and strength make it ideal for the WindDrive. Only by implementing the rope could Demotech achieve its 1:100 goal (see our Policy-page).

    Now the possibilities of harnessing the wind are in reach of everybody!

    Implementing the rope brought new possibilities to the design of the Wind-drive. The rope is essential to:

    1. Transmit power from the wind-wheel to the dynamo (instead of using a gear-reduction);
    2. Drive a fast spinning dynamo by a slow rotating wind-wheel;
    3. Harvest wind power from the outside rim of the wind-wheel;
    4. Fulfill the 1:100 adage;
    5. Separate the dynamo from the wheel; and
    6. Transmit power in a continues manner

    1. The rope for power transmission The transmission from the drive to the dynamo is done via a rope, so no gear-reduction is used. This is essential, because sprockets cannot be made in rural areas. They are too complicated and heavy for our usage. A simple rope does the trick. The power is drained from the outside rim, not the central axis. The only role for the axis is to support the wheel, it no longer a point of load application.
    2. The rope as gear reduction The drive is to rotate as slowly as possible, so that it is easier and much safer to handle. The risk of injuries is minimized and less demands are set on the bearings, the drive rotating slowly.
    3. Transmitting power from the outside rim. Conventionally, power is transmitted from the central axis. This puts high demands on the bearings and requires the building process to be very accurate. By transmitting the power from the outside circle of the WindRotor, the building process could be radically simplified.
    4. One to Hundred. The Wind-drive has to bought or made at a cost that even families with a very low income can afford. This puts great demands on the design and material use of the Wind-drive. Demotech believes only a cost-reduction by a factor 100 can ensure acceptance within communities in the third-world. In our Policy-page you can read more about the 1:100 statement.
    5. Positioning the generator
      The RopeDrive enables the generator to be positioned much below the WindRotor. ope also ENABLES The dynamo TO BE SEPARATED from the wind-wheel. In this it differs radically from other wind generators, where the axis of the Wind turbine is directly coupled. As the rpm of this axis is low, while the torque is high, its generator is a heavy device.
    6. Transmitting power in a continued manner The rope also ensures that power is transmitted continuously. Even if the structure would bend in a strong wind, the flexibility of the rope will secure power transmission.

      The hinge
      Next to the rope, the hinge is an important part of the wind-drive. To repair for instance the sails, the frame with the WindRotor has to be taken off. For this no climbing into the structure is needed.

      The costs involved in the Wind-drive. A few factors make it possible to afford the Wind-drive. The target price of the Wind-drive, including dynamo, batteries and charging current limiter, is $20,-.

      Primarily research done in our lab. Only the design and prototyping take place at Demotech's lab in Maastricht, the Netherlands. Actual construction is done by local craftsmen of the future users themselves. Demotech will deliver plans, materials and supervision during the building process at an affordable price, a hundred times more cost effective than expected. Some of the material need to be purchased: PVC pipe, lead for the batteries, all within the spectrum of cigarettes or batteries, but affordable items

      The labour force should be organized. If the project wants to succeed, more than one pair of hands will be needed. If desired, alterations can be made in the design to fit the requirements of the family. The plans Demotech delivers take these alterations into account and are highly flexible. No Wind-drive installed will be the same, every Wind-drive being a unique example proving that communal participation can work. The excitement to be part of the solution instead of difficulties described earlier raises expectations of what can be achieved with this approach . The user group is in control of the final design and building and can alter or change the design according to their own needs.

      WindDrive: The WindDrive ask for your imagination ...