Unconventional Wind Turbines
Most of the wind turbines being built today are of the type known as “HAWT” turbines. This stands for Horizontal-Axis Wind Turbine, and they generally have three blades. But that is certainly not the only type of wind turbine being designed or used.
|Many new and unconventional types of wind turbines are actually simple modifications of the original HAWT turbine.||
One such model is a Counter-Rotating Turbine, which allows the rotation speed of the generator to be increased.
When the turbines that rotate in different directions are mounted on the same side of the turbine tower, they are angled in a way that avoids the blades hitting each other. Sometimes the blades are set on opposite sides of the turbine tower, with the back blades designed to be smaller and faster. With this type of turbine, you can use wider wind speed ranges than you can with a single turbine.
A Diffuser Augmented Wind Turbine, also called a DAWT, features a turbine placed on the inside of a duct that flares out at the back of the unit. The ducted rotor also allows the generator to operate in a wide wind range, and it generates more power within each rotor area unit. You don’t need a gearbox with a DAWT, so the overall unit is smaller. But this type of wind turbine is also more complicated in its mechanism than is a standard turbine, and the duct is heavy, making the tower support more weight.
Counter-Rotating Horizontal Axis Turbines allow a turbine to use the rotational air flow that a standard wind turbine cannot use. The second rotor, placed behind the first, uses this airflow, and the unit can attain nearly 40-percent more energy in the same wind area as a standard turbine. This unit also does not use a gearbox, and you don’t need to use yaw mechanism or motors, since it auto-centers on the wind. You can also link these turbines in a grid without the use of electricity, so that arrays of this turbine type can be harnessed.
Co-Axial, Multi-Rotor Horizontal-Axis Turbines feature at least two rotors mounted to one drive shaft, both turning one generator. You can multiply the power generated as the wake top contacts the next rotor’s bottom portion. The energy generated can be increased by several times by the use of multiple, co-axial motors.
Twisting Blade and Furling Tail turbines are improvements made to wind turbines, and they are similar to the operation of variable pitch blades. These types of blades can increase greatly the turbine efficiency, and you can use this in do-it-yourself construction.
Telescopic Blade Turbines are able to change each blade’s length, to decrease or increase the area swept by the turbine. These blades create a more productive turbine when they increase the rotor diameter of the turbine when there is not a great deal of wind. During periods of high winds, the turbine can reduce its load by retracting the blades, making the rotor smaller.
The G-Model Wind Turbine has three wings that are positioned outside the classical turbine blades. This model can increase by nearly five times the blade efficiency of the classical blades, by allowing the turbine to adjust to the direction of the wind, in a method that does not require external power to be added. This turbine can start itself, and it works well in situations of low cuts in wind speed.
So, even though wind turbines themselves have not gone mainstream and are still considered to be unconventional, there are a sub-group of unconventional wind turbines trying to make their way into the mainstream as well.