Wind results from air in motion. Air in motion arises from a pressure gradient. Wind can be broadly classified as “planetary” & “local”. Planetary winds are caused by greater solar heating of the earth`s surface near the equator than near the northern or southern poles. This cause warm tropical air to rise and flow through the upper atmosphere towards the poles & cold air from the poles to flow back to the equator nearer to earth’s surface.
The power in the wind can be computed by using the concepts of kinetics. The wind mill works on the principle of converting kinetic energy of the wind to mechanical energy. The kinetic energy of any particle is equal to one half its mass times the square of its velocity, or ½ mv2.
A wind mill is machine for wind energy conversion. A wind turbine converts the kinetic energy of the wind’s motion to mechanical energy transmitted by the shaft. A generator further converts it to electrical energy. So it is necessary to keep in mind, while designing the windmill’s structural part.
Application of Wind-Turbine
Wind-turbine generators have been built a wide range of power outputs from kilowatt or so to a few thousand kilowatts, machine of low power can generate sufficient electricity for space heating & cooling of names & for operating domestic appliances. Low power WEC generators have been used for many years for the corrosion protection of buried metal pipe lines.
Application of somewhat more powerful turbines upto about 50kw, are for operating irrigation pumps. Navigational signal. Aero generators in the intermediate power range, roughly 100 to 25 kw. Can supply electricity to isolated populations.
Pumping Application :- A typical wind powered pumping application is onethat might use a horizontal –axis wind used to pump irrigation water. Large number water pumping wind mills have been used in Indian forms other applications that are being developed include the pumping of water for aqueducts or for pumped-hydro storage of energy.
Direct Heat Application :- Mechanical motion derived from wind power can be used to drive heat pumps or to produce heat from the friction of solid materials, or by the charining of water or other fluids or in other cases, by the use of centrifugal or other types of pumps in combination with restrictive orifices that produces heat from friction and turbulence when material having a high heat capacity such as water, stones, electric etc. or the heat may be used directly for such application as heating and cooling of water.
Electric Generation Applications :- Wind power can be used in centralized applications to drive synchronous a.c. electrical generator. In such applications, the energy is fed directly into power networks through voltage step-up transformers.