Wind Energy

Wind energy and photovoltaic energy are two renewable energies.

Photovoltaic is common between the individuals and wind between the energy corporations.

However some people have wind energy, very few I think, but many organizations have photovoltaic energy.

I only know one person who has a wind system and has a lot of problems with the neighbourhood cause by noise.

Both convert different energy in electricity:

i)?? The wind energy converts the wind kinetic energy in mechanical energy and this one in magnetic/electric energy.

ii)? The photovoltaic converts sun radiation in electrical energy.

The wind energy has some fascination over me from the childhood windmills as well the windmills and water mills that grind flour to make bread.

I remember making toy windmills and blowing them sideways,

parallel to the wings… and I found that they were more efficient

with the wind (Newton's third law states that for every action force, there is an equal but opposite reaction force).

It was only many years later that I understood that I had to blow perpendicular to (in front) of wings to be efficient.???

Exactly by the fascination I will go try to explain some physic/mathematic principles.??

?Wind air power over the wings:

We understand that the wind power change with: air density (temperature and height); rotor/wings (diameter and shape) and air speed (weather conditions and geography localization).

The annual power calculation is based on the probability of air speed around an average value.

Electrical energy: P_turbine=electrical energy=(R*I)?on an external load.

Power changes with air speed.

Comparing the two powers (kinetic and electrical) we understand that conversion efficiency is about 45% max.

Based on the air speed probability graph, we can draw the annual gross electrical energy graph:

Notes:

?{r=wing radius; W=angular speed of wing; v=wind speed; r*w=linear speed at the end of the wing}

TSR<3: slow generator and TSR>3: fast generator

If speed is too slow have a bad conversion of wind power to electrical power.

If speed is too fast the wing resistance to air increase with consequent losses.

2- The direction of rotation is clockwise – it is regulated because it has less impact when we look at them.

3- There is a mechanical ratio between the generator rotor (high speed) and the wing rotor (low speed).

#Wind energy