Capturing the earth’s natural energy through wind was once an abstract idea. Eventually, however, engineers were able to focus the idea and put it into action through innovative technology. Throughout the development of wind turbines, many prototypes were created, and many of the first ones designed are still used today, just with more modern engineering. Here are a few of the different wind turbines we are used to seeing today, and some we definitely are not.
HAWT Wind Turbines
A “HAWT” is a Horizontal Access Wind Turbine. These are the types of wind turbines that are most widely used, and are usually the first to come to mind when we think of wind energy. These turbines can have two, but more often three, blades on top of a tower reaching up to 120m tall. The blades can be upwards of 60m long and can produce up to 20 MW of energy.
These are turbines that face the wind. This means that the wind blows directly into the turbine, rather than coming from behind it. These are the HAWT wind turbines most often used.
Pro: This is the more efficient way to get energy from wind, given that it helps prevent wind shade from behind the tower.
Con: Wind shade occurs in front of the tower as wind comes toward it. To avoid this, the rotor must be further from the tower, which is an expensive shift.
These turbines do not face the wind, so the wind actually hits the back of the turbine to make it move.
Pro: The rotor can be made much more flexible. This means the wind shade can be more easily reduced, and a lighter model can be designed to take the stress off the tower in high winds.
Con: The wind power is variable because the wind blows directly through the wind shade. Although its design can more easily reduce wind shade, there is still significantly more in down-wind turbines.
Shrouded turbines, also known as Diffuser-Augmented Wind Turbines, have blades situated in a ring-shaped airfoil, which increases the airflow in the system.
Pro: As explained by Open Source Ecology, this design can increase the power of a HAWT by up to 5 times due to the increased air flow created from the airfoil. Turbulence and noise are also reduced because blade tips are covered by the airfoil.
Con: These are very expensive turbines and cannot compete with the modern, high speed turbines.
**VAWT Wind Turbines **
A “VAWT” is a Vertical Access Wind Turbine. These types of wind turbines harness power from the wind in the opposite direction than the HAWT. VAWT are used less frequently because their vertical design is not as effective or as efficient as the horizontal design.
This wind turbine is shaped like an “S” and works the same way as a cup anemometer. Wind is captured in its curves, which moves the contraption in a circle.
Pro: It is a much smaller design, which means it can be used as a “small scale” renewable.
Con: The blades have an extremely slow rotation speed, and therefore cannot produce as much electricity as other turbines can.
Flapping Panel Turbines
With this turbine, wind can come from any direction. It is designed with moving panels that are each attached to the base with two poles.
Pro: Wind can hit the turbine from any direction to produce power.
Con: This turbine lacks speed and durability in higher winds.
This is the most well known of the VAWTs. It has two to three “C” shaped blades that capture the wind.
Pro: This design is much smaller, so it produces less noise and requires much less space.
Con: They are not self starting, so they require extra energy to start, and its energy production does not compare to that of a HAWT.
This is powered by three vertical airfoils with horizontal supports.
Pro: This design is extremely inexpensive to make, and it is good in turbulent wind conditions.
Con: Besides the low cost, in comparison, it does not stand up to the energy production of HAWTs.
Overall, the HAWT designs come up on top for their high energy production at the lowest cost. Although VAWT are still useful on a smaller scale, the horizontal design is the best option for large scale wind energy production.
New turbine designs are coming out every day. There are even bladeless turbines now, that only require wind to move through the design, rather than needing the wind to circulate the design. They are even beginning to design turbines based off of how birds fly by using the nature of birds’ wings to learn how to better harness energy from wind using less material.
The fact that engineers have found a way to use wind to our human advantage is already impressive. The fact that more and more designs are coming out daily is just a bonus. Soon enough, the most efficient designs will be considered the norm for wind energy production.
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