Wind energy is energy that has the wind and that can directly be taken advantage of or to be transformed to other types of energy, like, for example, to electrica energyl.
The first use that is known the advantage of the wind dates from year 3,000 a.C. with the first Egyptian swift-sailing boats. Millenia later (s. VII in Persia) will arise the first mills from wind that will allow to grind grain or to pump water.
Nowadays electricity with great efficiency can take place, thanks to wind generators of great dimensions, also denominated wind turbines.
A wind generator is formed by a set of vanes (normally three) connected to a rotor that, by means of a system of gears, is connected to a generator ELT. All this machinery (wind turbine) is placed to the top of a mast or tower where there is more influence of the wind.
The length of the vanes will define the diameter of the area of sweeping of the same ones and, whichever greater it is this area, greater will be the power than it can generate a wind generator.
We can approximately find from small 400 W wind generators and 1m of diameter of vanes, to immense wind generators of the great 2,500 kW aeolian parks since 80 m of diameter of vanes.
Para pequeñas instalaciones de uso doméstico o agrario los aerogeneradores más útiles y asequibles
son los que tienen un diámetro de barrido de 1 a 5 m, capaces de generar de 400 W a 3,2 kW.
For small facilities of domestic or agrarian use the most useful and reasonable wind generators are those that have a diameter of sweeping of 1 to 5 ms, able to generate of 400 3.2 W to kW.
They need a minimum wind speed 11 km/h to start (as opposed to the 19 km/h of greatest), obtain its maximum yield to the 45 km/h and they are stopped with winds of more than 100 km/h to avoid damages, wearing downs or overheat in its mechanism.
In order to obtain a good yield it is necessary that the location of the wind generators is in a very windy region, with wind most of days of the year and with the 13 an average speed annual superior to km/h.
When a wind generator is connected directly to a load, replacing its generator ELT, denominates mill, and its extended function more is the water pumping.
He is very usual to find mills to pump water with many shovels, from 15 to 40, that they are able to far better take advantage of the wind at low speeds.
The most efficient mills can start with a wind speed of 4.8 km/h, and have the characteristic of not being able to increase their speed of rotation when arriving at a determined wind speed, around 28 km/h.
From this speed, they cannot take advantage of all the wind energy and always pump the same amount of water, diminishing therefore the efficiency of the mill.
Although it does not seem it, this characteristic is interesting since it allows to be able to pump water of more continuous form, taking advantage of so much the strong winds as the weak ones and avoiding to install great water tanks.