Wind energy is considered among the renewable energies, and wind farms in Europe and America are witnessing great growth, and in return for this there are still many inaccuracies revolving around this alternative energy.
Many people complain about wind turbines being a nuisance to them, although they do not cause much sound in many cases, unless the turbine is worn out, for example.
The same thing is said about small-sized domestic wind turbines. They are considered less annoying, especially the advanced ones. Compared to other things that emit a sound, the value of the sound emitted by these machines is almost non-existent. However, many opponents of wind turbines enumerate the negatives of this alternative energy. In this article, we will talk about this point.
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Although the first generation wind turbines were harmful from the pointFrom a sound point of view, it seems today that technological advances have allowedconsiderably reduce the sound generated by these machines. Indeed,on the scale below, the wind turbine is situated between 30 and 45 dB.The evolution of the level sound as a function of the number of wind turbines is logarithmic, i.e.the installation of a second wind turbine increases the sound level by 3 dB atinstead of doubling it.
Ntotal=10Log[10^(N1/10)+10^(N2/10)]=10Log[2*10^(N/10)]=10Log[2*10^(45/10)]=48,01 dB N:Noise. I:number of machines .
Thanks to improved technology, the mechanical sound associated with transmission and alternator has been significantly reduced through improved soundproofing of the platform and other measures such as modification or removal of gears.
On some models the trees transmission are placed on shock absorber bearings and othermodels of the insulation systems are present at the top of the mast allowing absorption of the propagation of vibrations and other mechanical noise to the structure.But despite this important progress, the perception of noise is different from one individual to another, and the feeling of gene is a very subjective phenomenon.
On the other hand, small wind turbines are generally very quiet because it is often the speed reducer of large machines which generates noise by strong wind. Note that the noise law (According to GE ) indicates that the sound emergence should not exceed 5 dBA during the day and 3 dBA during the day night. To this end, industrial wind turbines must maintain a distance from300 m from the houses.according to GE