Energy
Wind Energy
Wind energy is the oldest source of renewable energy used by man. It is the product of the conversion of the kinetic energy of the wind into other forms of energy. Through the wind power plants, this energy is mainly converted into electricity.
Into The nature of the terrain and the environment influence the direction and strength of the wind. Such as mountains and forests can reduce the power of the wind, as well as the buildings of large cities. For this reason, wind power plants can be localized only in some areas particularly favorable and not distributed on entire territory. The power of the wind is particularly strong where there are no obstacles, in surfaces, along the coast and in the open sea (offshore).
Into One can distinguish two types of wind turbines, in relation to the type of base module used: Wind turbine with vertical axis; Wind turbines with horizontal axis.
Wind turbines vertical axis
Into Advantages to the use of this technology are found in reduced noise level and reduced in size, which makes it easier and aesthetic integration in contexts citizens, where among other things the wind, usually turbulent, flow and direction and fl ow variables, is particularly suited to this type of generators.
Into The use of these devices is not to be excluded even in the uses of mountains, where with twenty very intense and gusts, the vertical axis is preferable, since the horizontal axis turbines have limits due to inertia of the masses in tangential and vertical movement, while the vertical axis turbine is indifferent to the rotation of the wind. The support structures also do not need to be especially robust and employment soil than plants blades is much more contained.
Windmills horizontal axis
Into This is the type of generators currently most widespread, of which the windmill can be considered the historian progenitor. The wind turbines have a height of between 40 and 100 meters to better capture the energy of the wind in an area undisturbed and free of obstacles. The dimensional aspect of wind turbines is to be taken into particular consideration during the design of wind farms, as the elevated height makes them visible even at great distances and has inevitably impact on the surrounding landscape.
The speed of the blades is controlled by a "control system" which performs two main functions:
- multiplies the speed to optimize the production of electricity ("gear box");
- Slows or blocks the speed of the blades in case of overload, and when the
wind force exceeds a certain critical ("braking");
The power of the wind turbines
Into The wind turbines can have very different powers. Into For large systems it is an average of 500 kW (0.5 MW) up to 3 MW. Powers are vastly larger than in the past, whereas twenty years ago the power of a wind turbine reached a maximum of 25 kW. Today, a single 1.5 MW wind turbine is equivalent to more than 60 wind turbines of 25 kW 80s, demonstrating the evolution linked to the technological research in this field. The new wind turbines are much larger than those of the 80s and provide an advantage in the economy of scale in the production of electricity. For domestic installations will normally be from 0.3 kW up to 2.5 kW. Into The production of electricity depends on the speed of the wind. Upon variation of wind speed, measured in m / s, the wind turbine will produce a different power of electricity. There are two thresholds, a minimum and a maximum, so that the wind turbine produces electricity: Below a certain minimum speed of the wind ("cut-in"), the wind turbine does not supply electricity and the rotor remains stationary. This minimum is generally linked to a wind speed of 3 meters per second, but depends on the characteristics dell'aerogeneratore, its size and the technology used. Above instead of a specific speed ("cut out"), the rotor dell'aerogeneratore stops spinning in order to avoid damage to the turbine. When recording wind speed exceeding 25 meters per second, typical of "cut out", the wind turbine does not produce electricity.
Focus on Small Wind
Delve into italian Wind Energy and the actual and future benefetis of small wind.