WIND ENERGY & WIND GENERATORS

Wind Energy is an indirect form of Solar Energy. About 1% of the total solar radiation that reaches earth is converted into energy of wind. Wind results from differential heating of the earth and its atmosphere by sun. As the sun heats different parts of the earth at different rates, air circulates from cold to warm areas producing winds. Wind energy has been used for thousands of years to propel sailing ships and for pumping water and grinding grain.

The application of wind energy has several advantages like:

• low gestation period
• no raw-material cost
• non-polluting etc.

Wind generators harness the wind energy to produce electricity.


The two essential components of a wind generator are:
1)wind turbine and
2)generator.

Ofcourse, there is another component. it is the pole on which the entire apparatus is mounted.

The wind turbine converts the energy of the wind into rotational energy. The rotational energy is used by the generator to produce electricity

Inside the body of a generator, there is a coil of wire and a magnet. When a coil of wire is moved inside a magnetic field, it produces an electric current in the wire - the same principle as a dynamo on a bicycle, but the wind provides the movement, not your legs.

Wind generators come in many sizes and shapes, from small units found on caravans and boats to enormous machines that can power a whole village. Wind farms have many generators which produce a large amount of power. Some people object to wind generators on the grounds that they can be noisy and may be thought to spoil a beautiful view. Recently, wind farm planners and engineers have improved the noise problem considerably. Many people living near wind farms think that they enhance the view.

Perhaps the ultimate solution is to put wind generators offshore, where winds are strong and there are no neighbours.

Benefits

Wind generators are the main viable alternative to fossil fuels and nuclear power : as such wind power has the potential to replace currently existing generating technologies which cause a wide range of environmental problems. Wind power does not contribute in use to climate change or acid rain, and does not create a hazardous waste storage problem.

Wind generators have a good energy ratio: they generate many times the energy needed to make them(this is not the case with solar Panels). Also, it is easy to decommission wind power installations (unlike the nuclear power plants); most of the materials are easily recyclable using existing technologies.

Greater use of wind power means less dependency on remote fuel sources, with the problems of transport and military involvement that brings.

Wind power is suitable for small installations, unlike many other generation technologies which are only viable on a large scale.

Safety and reliability are good - a properly installed wind generator will operate without problems for 20 years or more, and there is no record of any member of the public ever being harmed by an operational wind turbine.

What can we do?

It’s a good idea to combine wind with solar, to take advantage of all weather conditions (plus the wind blows at night) to provide all, or contribute to, your energy needs.

If you want to provide all your needs, the first task is to reduce energy use and become more energy efficient, otherwise it will be quite expensive. Wind generators are ideal for boats and caravans though, where less electricity is needed, and also for remote, off-the-grid homes, in conjunction with a diesel generator - especially if heating is solid fuel, and cooking is with bottled gas.
Check the wind speeds at your location, or monitor them yourself - you can get monitoring equipment from wind and sun, then look at graphs provided by manufacturers for their turbines to see what power (in Watts) you will get for your average windspeed. Divide by 1000 to get kW, and multiply by the number of hours in a year (8760) to find the kWh generated per year (a kWh is a unit of electricity and can be found on your electricity bill).
Talk to your local planners (for a small turbine, this shouldn’t be a problem), and choose a site away from trees and buildings (rural areas are much better sites for wind generators).
Decide whether you will use a battery bank, or be grid connected (in effect using the grid as a store instead of batteries). There are environmental problems in the manufacture and disposal of batteries, but electricity companies often pay a lot less for energy received than supplied (although this may be changing). There is a third way, called grid interface. Batteries are used but the grid kicks in via a transfer switch if the batteries get low. You can slowly add more wind and solar to reduce the need for grid power.
You can buy 12-volt domestic appliances, in which case you just need batteries and a regulator, or you can use normal 240v appliances, but you’ll need an inverter too. You can self-install or you can employ a professional.
In some countries (for ex : U.K) a government grant is available for wind generator installations.

HAWT's and VAWT's

Horizontal Axis Wind Turbines & Vertical Axis Wind Turbines are the two types of Wind turbines.


Horizontal Axis Wind Turbines (HAWT) :
Horizontal Axis Wind Turbines are built with a propeller-type rotor on a horizontal axis (i.e. a horizontal main shaft).
HAWT's are the most common types of wind turbines you can see. most of the commercially installed wind generators are of this type.










Vertical Axis Wind Turbines (VAWT) :
The only vertical axis turbine which has ever been manufactured commercially at any volume is the Darrieus machine, named after the French engineer Georges Darrieus who patented the design in 1931. The Darrieus machine is characterised by its C-shaped rotor blades which make it look a bit like an eggbeater (you can see it in the image on the right). It is normally built with two or three blades.




Source: EcologyEngineers