A wind generator is a device which harnesses the kinetic energy of wind, and converts it to mechanical energy which is eventually used to produce electricity. While the term wind generator was specifically used to refer to wind turbines earlier, the invention of 'Windbelt' has changed the equations of late.
However, that hasn't stopped people from using the terms wind turbine and wind generator simultaneously. It is the search for an alternative source of energy - which is renewable and environment-friendly, that has turned all the eye balls on wind energy which is believed to be an apt replacement for fossil fuels.
As mentioned earlier, a wind generator or wind turbine is a device which is used to convert the kinetic energy of wind into mechanical energy for the production of electricity. There exist two types of wind turbines horizontal-axis wind turbines (HAWT) and vertical-axis wind turbines (VAWT), both of which boast of being better than the other.
While the horizontal-axis wind turbines are the ones which resemble a fan, the modern vertical-axis wind turbines resemble an egg-beater to a certain extent. From here on, we'll be discussing vertical-axis wind turbines (VAWTs) - at times also referred as vertical-axis wind generators, which boast of having many advantages over their horizontal counterparts.
Vertical-Axis Wind Turbines (VAWTs)
Basically, a vertical-axis wind turbine - or vertical wind generator, is a type of wind generator in which the main rotor shaft is fixed vertically, while the generator and other components which produce electricity using the mechanical energy are located at the base.
As a result of this, these generators are either erected on the ground or on the roof of a building (with the experts suggesting that a chimney is an ideal place for the same). This is in stark contrast of horizontal wind generators, wherein the main rotor shaft and electrical generator are housed on a top of the tower.
These wind generators have come a long way from the crude models of past - with an efficiency of 5 - 10 %, to the latest variants which promise an efficiency of around 30 %. Do these wind generators really have an edge over horizontal wind generators? Now that is something which can be only determined by evaluating their advantages and disadvantages.
By far the biggest advantage of vertical wind generator is the fact that it is not mandatory for this device to face the direction of wind. Irrespective of which direction the wind is blowing from, these turbines can harness its kinetic energy and use it for generation of electricity. More of such advantages of this device are given here:
- These wind generators can adapt to change in wind direction very well.
- They can be installed on the chimney or some other tall structure with ease.
- Maintenance is not a major issue as the device is generally within the reach.
- As the generator is within your reach, even repair work doesn't require much efforts.
- There is no stress on the supporting structure as in case of horizontal wind generator.
- As they require limited space, these devices can be spaced close to each other in a wind farm.
- Manufacturers also claim that these wind generators do not cause noise pollution.
Even though these advantages may make vertical wind generators seem quite promising, there also exist some disadvantages of these devices which you can't afford to turn a blind eye to. Given here are some of these disadvantages that you need to take into consideration when you evaluate their efficiency.
- The low installation height of these generators makes them dependent on low level winds.
- The additional drag that they are subjected to as they rotate into the wind further lowers their efficiency.
- Even though the manufacturers boast of amazing efficiency, at 30 percent they are no better than HAWTs.
- The chances of these wind generators stalling when subjected to gusty winds cannot be ruled out.
- These wind generators are efficient to their predecessors, but again they are quite expensive as well.
Vertical-axis wind generators come in various shapes and sizes, ranging from small ones for home use to large variants for commercial production of electricity. A good quality vertical-axis wind generator for home use can cost you anywhere between $500 to $25,000, with the higher end models being more productive than their inexpensive counterparts.
While these generators are ideal bet if you intend to produce your own renewable energy, you should evaluate their pros and cons (and compare them with horizontal-axis wind generators) in order to decide whether they are ideal for your region.