471 2004 1wind energy,cagri imir

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Phys 471Solar Energy I

WIND ENERGYByARI MR

InstructorProf. Dr. AHMET ECEVT

METU

2004-1


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CONTENTS1. Introduction2. History of Wind Machines3. Wind Resource4. Wind Energy Technology

Horizontal Axis turbine Vertical Axis turbine

5. Wind turbine Use6. Wind energy in Turkey7. Environment8. Economics

9. Conclusion

References


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1-INTRODUCTION

Wind energy, the world's fastest growingenergy source, is a clean and renewablesource of energy that has been in use forcenturies in Europe and more recently in theUnited States and other nations [11].

And todays world wind is one of thecheapest and cleanest energy source.


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2-HISTORY of WIND MACHINES

Throughout history people have harnessed the wind. Over 5,000 years ago,the ancient Egyptians used wind power to sail their ships on the Nile River.Later people built windmills to grind their grain. The earliest known windmillswere in Persia (the area now occupied by Iran). The early windmills looked likelarge paddle wheels.Centuries later, the people in Holland improved the windmill. They gave itpropeller-type blades and made it so it could be turned to face the wind.Windmills helped Holland become one of the world's most industrializedcountries by the 17th century.

American colonists used windmills to grind wheat and corn, to pump water, andto cut wood at sawmills.Last century, people used windmills to generate electricity in rural areas thatdid not have electric service. When power lines began to transport electricity torural areas in the 1930s, the electric windmills were used less and less.Then in the early 1970s, oil shortages created an environment eager foralternative energy sources, paving the way for the re-entry of the electricwindmill on the world landscape [1].


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3-WIND RESOURCE

Where Wind Energy Comes From All renewable energy (except tidal and geothermal

power), and even the energy in fossil fuels,ultimately comes from the sun. The sun radiates of1.74 x 10 watts energy to the earth per hour.

About 1 to 2 per cent of the energy coming from

the sun is converted into wind energy. That isabout 50 to 100 times more than the energyconverted into biomass by all plants on earth [2].

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What Wind Is

Wind is simply air in motion. It is caused bythe uneven heating of the earth's surface bythe sun. Since the earth's surface is madeup of land, desert, water, and forest areas,the surface absorbs the sun's radiationdifferently [1].


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Wind Resources

Global winds

Local Winds Land Breezes and Sea Breezes Mountain Breezes and Valley Breezes
http://www.windpower.org/en/tour/wres/geostro.htmhttp://www.windpower.org/en/tour/wres/mount.htmhttp://www.windpower.org/en/tour/wres/geostro.htmhttp://www.windpower.org/en/tour/wres/geostro.htm


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Global WindsThe wind rises from the equator and moves north and south inthe higher layers of the atmosphere as shown in figure 1 [2].

Around 30; latitude in both hemispheres the Coriolis forceprevents the air from moving much farther. At this latitude there is

a high pressure area, as the air begins sinking down again.

As the wind rises from the equator there will be a low pressurearea close to ground level attracting winds from the North andSouth.

At the Poles, there will be high pressure due to the cooling of theair [3].


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Figure 1 Global winds.


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Local Winds

Land Breezes and Sea Breezes Land masses are heated by the sun more quicklythan the sea in the daytime. The air rises, flowsout to the sea, and creates a low pressure atground level which attracts the cool air from thesea. This is called a sea breeze. At nightfall thereis often a period of calm when land and seatemperatures are equal.

At night the wind blows in the opposite direction.The land breeze at night generally has lower windspeeds, because the temperature differencebetween land and sea is smaller at night [2].


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4-WIND ENERGY TECHNOLOGY

Horizontal Axis TurbineVertical Axis TurbineOld-fashioned windmills


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Horizontal Axis Wind Turbine

Most of the technology described in this project is relatedto horizontal axis wind turbines (HAWTs,) as shown infigure 2.The reason is simple: All grid-connected commercial windturbines today are built with a propeller-type rotor on ahorizontal axis (i.e. a horizontal main shaft).The purpose of the rotor, of course, is to convert the linearmotion of the wind into rotational energy that can be usedto drive a generator. The same basic principle is used in amodern water turbine, where the flow of water is parallel tothe rotational axis of the turbine blades [5].


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Figure 2 Horizontal axis Turbine [6].


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Vertical Axis Wind Turbine As you will probably recall, classical waterwheels let the water arrive at a right angle(perpendicular) to the rotational axis (shaft)of the water wheel.Vertical axis wind turbines (VAWTs) are abit like water wheels in that sense. (Somevertical axis turbine types could actuallywork with a horizontal axis as well, but theywould hardly be able to beat the efficiencyof a propeller-type turbine).


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The only vertical axis turbine which has ever

been manufactured commercially at anyvolume is the Darrieus machine, namedafter the French engineer Georges Darrieuswho patented the design in 1931. (It wasmanufactured by the U.S. company FloWindwhich went bankrupt in 1997). The Darrieusmachine is characterized by its C-shapedrotor blades which make it look a bit like aneggbeater. It is normally built with two orthree blades As shown in figure 3 [5].


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Figure 3 Vertical axis wind turbine.


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Advantages of VAWTs

1) You may place the generator,

gearbox etc. on the ground, and youmay not need a tower for the machine.2) You do not need a yaw mechanismto turn the rotor against the wind [5].


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Disadvantages of VAWTs

1) Wind speeds are very low close to groundlevel, so although you may save a tower,your wind speeds will be very low on the

lower part of your rotor.2) The overall efficiency of the vertical axismachines is not impressive.3) The machine is not self-starting (e.g. aDarrieus machine will need a "push" beforeit starts. This is only a minor inconveniencefor a grid [5].


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Old-fashioned windmills

Figure 4 Old-fashioned windmills.


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5-WIND TRIBUNE USE

Electricity for homes and farmsElectricity for communitiesElectricity in industry Supplying electricity for a nation Remote communities

Energy to drive pumps


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Electricity from turbines

As shown in figure 5 a wind turbine consists of six majorcomponents : A rotor that aerodynamically converts the wind energy intomechanical energy on a slowly turning shaft.

A gearbox that increases the rotor-shaft speed for the

generator. Some specially designed generators run at rotor-shaft speed and do not need a gearbox. A generator that produces electricity. A control and protection system that optimizes performanceand keeps the machinery operating within safe limits.

A tower that raises the rotor high off the ground where thewind speed is greater and the effects of local obstructionsare less.

A foundation that supports the wind turbine system,sometimes with the aid of guy wires [7].


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Figure 5 Major components of horizontaland vertical axis wind turbines .


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Wind turbine generators produce a range ofelectricity. Rotors that have diameters ofabout 1m produce a few hundred watts ofelectricity. Rotors that have diameters thatapproach 75 m can produce over onemegawatt [7].


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Electricity for Homes and Farms

Small and medium wind turbine generators athomes, farms or small industrial sites can beused with diesel generators or connected tothe electrical supply grid. By connecting to theelectrical grid, the user of the electrical supplypays only for the electricity they use from the

electrical utility company [7].


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Electricity in Industry

Medium systems (10 to 100 kilowatts) can be usedby large farms, process industries, and groups ofindividuals to offset costs of electricity from thegrid network, or by remote communities to offsetfuel costs and pollution of diesel power plants.Large systems (100 kilowatts to 1 megawatt) canbe used either individually or in small clusters to

provide electricity to industries, large farms, orgroups of dwellings. When used in arrays ofmultiple units, they can supply significant amountsof electricity to provincial or national networks [7].


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Supplying Electricity For A Nation

Arrays of large wind turbine generators canbe connected to electricity supply grids andcan provide significant amounts of provincialand national electrical demand. In Denmark,for example, wind-generated electricity now

provides about 10 % of national needs andis scheduled to provide 50 % of the need by2030 [7].


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Remote Communities

Small wind turbine generators that areconnected to batteries can provide sufficientelectricity for rural dwellings,communications relay stations, navigationalaids, and other needs in isolated areas.Small and medium wind turbines may alsobe used for pumping, either by direct driveor by powering electric pumps [7].


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As shown in figure 6 the pump can belocated in the following places:

on top of the tower at the turbine rotorshaftat ground level, in which case shafting orpulleys are usedat the bottom of the well, in which case areciprocating pump with a long "dipper rod"

is used [7].


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Figure 6 Mechanical and wind-electric water-pumpingwind systems.


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6-WIND ENERGY IN TURKEY

Turkish wind energy association was foundedin 1992. by the help of energy ministry firstturbines built at zmir - eme -Alaat by ARES

G BRL co. This turbines produces 7,2MW energy. In the same years DEMRERHOLDNG built turbines at anakkale-Bozcaada which produces 10,2 MW. Todayworking is still going on to built new turbinesat zmir - eme, anakkale - Karacaren,MulaData, Balkesir - Bandrma [12].


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7-ENVIRONMENT

Wind energy is considered a green powertechnology because it has only minor impactson the environment. Wind energy plantsproduce no air pollutants or greenhousegases. However, any means of energyproduction impacts the environment in some

way, wind energy is no different [8].


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Aesthetics and Visual Impacts Elements that influence visual impactsinclude the spacing, design, and uniformityof the turbines.

Birds and Other living ResourcesPreconstruction surveys can indicatewhether birds or other living resources arelikely to be affected by wind turbines.
http://search.nrel.gov/query.html?col=eren&qc=eren&qm=1&si=0&ht=1981055060&ct=643335372


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NoiseLike all mechanical systems, wind turbinesproduce some noise when they operate. In recentyears, engineers have made design changes toreduce the noise from wind turbines.

TV/Radio InterferenceIn the past, older turbines with metal bladescaused television interference in areas near the

turbine. Interference from modern turbines isunlikely because many components formerly madeof metal are now made from composites.


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Global Warming Wind energy can help fight global warming.Wind turbines produce no air emissions orgreenhouse gases [9].


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Figure 7 Economics of wind energy.


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A simple tribune cost in

Figure 8 cost of wind energy [11]


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Wind energy is one of thecheapest energy sourceWe can compare windenergy source with anothersources in graphic 2 [10].


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Graphic (2) cent/kwh&energy sources.


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CONCLUSION

This is true that today's world need moreclean and more cheap energy. As I try tomentioned in this project wind energy is theone of the best way of clean and cheapenergy. And also it is understood that in thefuture most of our energy source will based

on wind energy.


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References

1. http://lsa.colorado.edu/essence/texts/wind.htm 2. http://www.windpower.org/en/tour/wres/index.htm#note1 3. http://www.windpower.org/en/tour/wres/globwin.htm 4. http://en.wikipedia.org/wiki/Wind 5. http://www.windpower.org/en/tour/design/horver.htm E6. http://www.me3.org/issues/wind/ 7. http://www.canren.gc.ca/tech_appl/index.asp?CaId=6&PgId=219 8. http://www.eere.energy.gov/RE/wind_economics.html9. http://www.personal.psu.edu/users/p/b/pbl108/new_page_3.htm10. http://www.german-renewable-

energy.com/downloads/pdf/wwec/economics_wind.pdf 11. http://solstice.crest.org/wind/index.html 12. http://www.meteor.gov.tr/2003/sorucevap/ruzgaren/ruzgarenergel.ht

m
http://lsa.colorado.edu/essence/texts/wind.htmhttp://www.windpower.org/en/tour/wres/index.htmhttp://www.windpower.org/en/tour/wres/globwin.htmhttp://en.wikipedia.org/wiki/Windhttp://www.windpower.org/en/tour/design/horver.htmhttp://www.me3.org/issues/wind/http://www.canren.gc.ca/tech_appl/index.asp?CaId=6&PgId=219http://www.german-renewable-energy.com/downloads/pdf/wwec/economics_wind.pdfhttp://www.german-renewable-energy.com/downloads/pdf/wwec/economics_wind.pdfhttp://solstice.crest.org/wind/index.htmlhttp://www.meteor.gov.tr/2003/sorucevap/ruzgaren/ruzgarenergel.htmhttp://www.meteor.gov.tr/2003/sorucevap/ruzgaren/ruzgarenergel.htmhttp://www.meteor.gov.tr/2003/sorucevap/ruzgaren/ruzgarenergel.htmhttp://www.meteor.gov.tr/2003/sorucevap/ruzgaren/ruzgarenergel.htmhttp://solstice.crest.org/wind/index.htmlhttp://www.german-renewable-energy.com/downloads/pdf/wwec/economics_wind.pdfhttp://www.german-renewable-energy.com/downloads/pdf/wwec/economics_wind.pdfhttp://www.german-renewable-energy.com/downloads/pdf/wwec/economics_wind.pdfhttp://www.german-renewable-energy.com/downloads/pdf/wwec/economics_wind.pdfhttp://www.german-renewable-energy.com/downloads/pdf/wwec/economics_wind.pdfhttp://www.canren.gc.ca/tech_appl/index.asp?CaId=6&PgId=219http://www.me3.org/issues/wind/http://www.windpower.org/en/tour/design/horver.htmhttp://en.wikipedia.org/wiki/Windhttp://www.windpower.org/en/tour/wres/globwin.htmhttp://www.windpower.org/en/tour/wres/index.htmhttp://lsa.colorado.edu/essence/texts/wind.htm

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