Vertical Axis Wind Turbine

Vertical Axis Windmills: More Populare Than Ever

A vertical axis wind turbine is a wind powered machine that converts kinetic energy in wind into mechanical energy.

A vertical axis wind turbine has a rotor shaft which runs vertically. Its main rotor shaft and vertical wind generator are placed at the bottom of the tower.

Its blades are attached to a central vertical shaft, which is then attached to an alternator located at the bottom of the shaft, sometimes at ground level. As such, when the blades rotate, they cause the rotor of the vertical wind generator to spin, thereby producing electricity.

Vertical axis windmills are always oriented to the wind, unlike other wind turbines which turn in the wind as the wind direction changes because of their tail vane. They are also seemingly immune to turbulence which tends to wreck havoc on the horizontal axis wind turbines.

The vertical turbines also have an advantage over the latter in regards to dealing with wind direction shifts. Some of the types of vertical axis wind turbines available today include the Giromill, the Darrieus Wind Turbine, the Windmill with Rotational Sails, as well as the Savonius Wind Turbine.

Advantages

One advantage of a vertical setup is that its rotor shaft is placed vertically, and can therefore be positioned near the ground. The vertical wind generator and gearbox are also located near the ground, and as such they do not require the tower to provide support. Moreover, the turbine does not have to be pointed into the wind, which makes the maintenance of this wind turbine rather simple.

The vertical axis wind turbine is also very cost effective to use as it can be positioned on top of hills, mesas, ridge lines or any other place where the wind produces more force near the ground.

Because these turbines may be positioned at lower heights to capture ground-level winds, they can therefore be placed in areas where tall devices are prohibited by law. This is turn saves you the time and money you would need to obtain zoning variances in order to mount your tall expensive towers.

Another advantage of the vertical axis wind turbine is that it can turn in any direction with the wind.

Disadvantages to Consider

One disadvantage of the vertical axis wind turbine is that it cannot cover a large area of wind. This is because you will need to install it in a relatively flat area of land in order to enable it to cover a larger area of wind sweep.

Because these turbines operate near the ground where there is turbulent air flow, they therefore lack efficiency when it comes to energy extraction. This is because just as it would happen with any turbine installed on a short tower, the vertical axis wind turbine will experience friction when trying to capture the ground level winds.

Another disadvantage of vertical axis wind turbines is that their blades are prone to fatigue which is caused by the centrifugal forces that act on the blades as they spin around the central axis. These vertical blades twist and bend as they rotate in the wind, therefore becoming flexed and cracked.

As time goes by, the blades may break apart and cause the machine to malfunction. If you place a vertical axis windmill behind a building, it will not function because of the dead air spaces and other ground clutter.

Consumer Reviews

Consumers like

• Easy to maintain
• Cost effective
• Turns in any direction
• Can be positioned anywhere

Consumers don’t like

• Cannot cover large area of wind
• Operates only near the ground
• Inefficient energy extraction
• Blades break apart over time

Summary

Vertical axis windmills have been in existence for thousands of years, but are not as popular due to their unreliability and inefficiency. Although this has not put a stop to their production, with manufacturers claiming that they can capture wind from any direction, which is also true for horizontal axis windmills as well.

In comparison to horizontal axis wind machines, vertical axis types are less efficient and reliable as they do not extract as much wind energy.