proiect rei.doc

8/14/2019 Proiect REI.doc

1/35

Project at MREI

Coordinating Professor Students:Serban Ioan Aldea Gabriel

Joanta Ioana

Nita Cosmin

Popescu Radu

Tatu Irina

1


2/35


3/35

Table of contents

1.Project Theme...........2

2.Table of contents..

.!ind Turbines .."

.1.#eneralities.."

".$hosen sites...%

&.$omponents..12

'.Optimization.1(

'.1#eneral )iew1(

'.2*imulations1+

%.$onclusion."

(.,iblioraph..&


4/35

3.Wind turbines/'0

3.1.Generalities:

!ind power is the conversion of wind ener into a useful form suchas electricit usin wind turbines. The technolo of wind turbines issimple. !ind turbines capture the inetic ener of wind with in most casestwo or three blades shaped much lie airplane propellers. These blades areattached to a tower. !hen the wind stries the blade the anle andconfiuration of the blade form a pocet of low pressure on the downwindside of the blade. This low pressure sucs the blade into movement causinthe rotor to turn. 3orce is added b the hih pressure on the upward side ofthe blade. 4n aerodnamic theor this propert is called lift. 4f the blade isdesined correctl lift is stroner than dra or the slowin force exerted bthe wind on the front of the blade. 4n wind turbines lift and dra wortoether to mae the entire mechanism spin lie a propeller. The process isthe opposite of that of a fan. !ith a fan electricit is used to mae wind.!ith a wind turbine wind is used to produce electricit. The turnin rotor ofa wind turbine is connected to a shaft which is connected to an electricenerator. Power can be distributed to users over the electric rid in exactlthe same wa an other electric power is distributed. The most importantfeature in the operation of wind turbines is lift. To achieve lift wind turbinedesiners have borrowed technolo from aircraft desiners. 4n cross-section

an airplane win loos lie an irreularl shaped teardrop. The shape isirreular because the win5s bottom is slihtl flatter than the top which ismore curved. !hen a plane flies its wins slice throuh the air creatinwind. ,ecause of the curve of the upper surface of the win the air has toflow faster to et around the win. 6t the same time the air flows at a lowerspeed alon the bottom surface of the win. ,ecause of the difference inspeed the air above the win is less dense7 that is the air pressure is lowerthan the pressure of the air below the win. This difference in pressurecreates lift perpendicular to the direction of the movin air allowin the

plane to fl. The same principle applies to turbine blades. 8nlie airplanewins wind turbine wins are almost alwas twisted. The reason the aretwisted has to do with another aerodnamic principle stall. !hen anairplane win is tilted bac the wind continues to flow smoothl alon the

bottom surface but alon the top surface because of the steeper anlepresented to the wind the air no loner stics to the win but swirls aroundin a circle above it. The result of this swirlin is the loss of the low pressure

"


5/35

alon the upper surface of the win. !ithout this low pressure the plane hasno lift and drops lie a roc. 8nlie airplane wins wind turbine blades areconstantl rotatin and the speed of the rotation differs alon the entirelenth of the blade. 6t the precise eometric center the speed of rotation iszero. This speed steadil increases alon the lenth of the blade until at thetip the blade can be movin hundreds of feet 9meters: per second. Thisrotation chanes the direction at which the wind hits the blade all alon itslenth. 4n effect the anle at which the wind hits the blade would bedifferent at each point alon the blade if the blade were not twisted. !henthe blade is twisted the anle at which the wind hits the blade is the same ateach point and stall is eliminated under normal wind conditions.;xcessivel hih wind speeds can damae rotors however so enineershave desined blades that stall when the wind is too stron and the rotorstops spinnin.

Tpes of wind turbines< =orizontal-axis wind turbines 9=6!T: have the main rotor shaft andelectrical enerator at the top of a tower and must be pointed into the wind.*mall turbines are pointed b a simple wind vane while lare turbinesenerall use a wind sensor coupled with a servo motor. >ost have aearbox which turns the slow rotation of the blades into a ?uicer rotationthat is more suitable to drive an electrical enerator.*ince a tower produces turbulence behind it the turbine is usuall pointedupwind of the tower. Turbine blades are made stiff to prevent the bladesfrom bein pushed into the tower b hih winds. 6dditionall the blades are

placed a considerable distance in front of the tower and are sometimes tiltedup a small amount.@ownwind machines have been built despite the problem of turbulence

because the donAt need an additional mechanism for eepin them in linewith the wind and because in hih winds the blades can be allowed to bendwhich reduces their swept area and thus their wind resistance.

-)ertical-axis wind turbines 9or )6!Ts: have the main rotor shaftarraned verticall. Be advantaes of this arranement are that the turbinedoes not need to be pointed into the wind to be effective. This is an

advantae on sites where the wind direction is hihl variable. )6!Ts canutilize winds from varin directions.!ith a vertical axis the enerator and earbox can be placed near theround so the tower doesnAt need to support it and it is more accessible formaintenance. @rawbacs are that some desins produce pulsatin tor?ue.@ra ma be created when the blade rotates into the wind.4t is difficult to mount vertical-axis turbines on towers meanin the are

&


6/35

often installed nearer to the base on which the rest such as the round or abuildin rooftop. The wind speed is slower at a lower altitude so less windener is available for a iven size turbine. 6ir flow near the round andother objects can create turbulent flow which can introduce issues ofvibration includin noise and bearin wear which ma increase themaintenance or shorten the service life. =owever when a turbine is mountedon a rooftop the buildin enerall redirects wind over the roof and this candouble the wind speed at the turbine. 4f the heiht of the rooftop mountedturbine tower is approximatel &CD of the buildin heiht this is near theoptimum for maximum wind ener and minimum wind turbulence.6 wind turbine has the followin components6=-muh-tuhr:

3iure 1. !ind turbine components [8]

'


7/35

4.Chosen sites

3irst step is to chose three sites !e chose three sites because we wantto see to importance of the chosen site. 3or this we must consider the climate

and the eoraphical position.

3iure 2. *olar radiation in Fomania/10

!ith data obtained from the ;uropean $ommunit9fi.1:we chose a hotspot a central spot and between them.

Therefore we havear 6pr >a Mun Mul 6u *ep Oct Hov @ec

3iure ". *olar 4rradiation N !ind *peed 3or 3aaras Fomania/0

3or this location we have the followin overview of wheatear conditionsar 6pr >a Mun Mul 6u *ep Oct Hov @ec

3iure &. *olar 4rradiation N !ind *peed 3or 4asi Fomania/"0

3or this location we have the followin overview of wheatear conditions2CC@$onverter< &B!

,or the first situation 0e ha9e:The averae electrical production for the chosen location is,atter< )ision'3>2CC@$onverter< &!

The averae electrical production for the chosen location is2CC@$onverter< &!

The averae electrical production for the chosen location is2CC@$onverter< &B!Price < 2+2'%

*stem architecture2CC@$onverter< &B!

,or the first situation 0e ha9e:

The averae electrical production for the chosen location is


30/35

$hosen location< 4asi Latitude: 4%J1%! Longitude: "%J&% Horth eastFomania.8sin the sstem architecture2CC@$onverter< &B!Price < 2'1

*stem architecture


34/35

%.Con


35/35

8.ibliogra'h

1:http

proiect rei.doc

Documents