19 December 2005
19 December 2005
A novel wind turbine named 'Wind Wandler' by its German designers, is offering a more feasible domestic wind energy option for urban areas due to its silent operation.
The helical turbine designed in contrast to the more common bladed design is claimed to be a more efficient form of developing wind energy for domestic users. The wind turbine has been given the name the 'Wind Wandler' and was developed by a small German company called MatroW based in Ladenburg.
The company's managing director Wilhelm Hermann Josef designed the Wind Wandler as a means of increasing the efficiency of bladed wind turbines utlilising modern advances in materials.
The form the developers picked was originally conceived to work in water, but the availability of modern composites allowed it to be made somewhat larger and lighter than would previously have been possible.
The first production units consist of two spiral vanes of glass fibre reinforced materials which are 1m in diameter, 1.39m long and sit in a hemispherical yoke so they are supported at both ends. Output at 14m/s is about 1 kW. The disk armature generator is rated at 3.5kW and, unlike bladed turbines, they do not have to be stopped in high winds. Rotation speed at 24m/s wind is 1,400 rpm, but remains the same at 30m/s because surplus high speed air then tends to spill round the rotating turbine. The turbines turn naturally into the wind.
Herr Josef explained that they are 53% efficient, as opposed to 46% for conventional bladed turbines, and the theoretical maximum efficiency that can be attained is 59%.
The turbines are designed to be quieter when they rotate, which he says, is because they have no blade tips to shed vortices. Total weight of turbine and generator without mast is 39kg. Noise level at 1400 rpm is 42 dBA. The company is selling the units at a price of 6,300 euros each.
When the turbine is operating at high speed, the turbine not only turns the load but also increases the flywheel speed through the eddy current coupling. However, when the flywheel is going faster than the turbine, the flywheel continues to turn the load through the eddy current coupling, but the mechanical clutch is disengaged so that it does not try to turn the turbine as well. Coupling the flywheel through an eddy current coupling greatly reduces peak loads on input and output shafts and gears.
The wings, stretch out and curve in the axial plane and a radial direction. Because of its light induced resistance, in comparison with ordinary systems the effectiveness is much higher.
The special shape of the spiral wings produces a strong reduction in stream wind loss. Furthermore, it is possible to obtain high rotation speeds. Different wind directions are no obstacles because it automatically turns into the wind. It is also possible to use the wind converter outside the specific wind areas. It derives advantage of weak and turbulent winds. The ‘silent runner’ (about 46 dBA with 1.400 r/min) allows locations in more populated areas.
The Wind Wandler follows a number of recent developments in promoting wind energy for domestic use. British Gas, the UK energy supplier recently announced details of its plans to develop domestic energy for the UK.
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