WIND ENERGY

CONSTRUCTION

MOHAMMED SHAHARZAD M.KSHANID.PSINJNA V.S

HOW WIND IS GENERATED?

• Wind is caused by the uneven energy distribution and rotation of the Earth.

Heat Pressure gradients Motion

Wind generation

Cont.…Day time Night time

Cont...

HISTORICAL DEVELOPMENT In 4000 BC Egyptians used wind power to sail boats in

Nile river.By 10th centaury wind mills used to grind grain in Iran

and Afghanistan.Then in China wind mills were used to raise water for

irrigation and sea water for production of salt. In 1854 Daniel Halladay in US introduced a wind pump

and used for irrigation and industrial applications. In 1880 P. La’cour used wind mill as a source of

electricity. In 1929 French engineer Darreius built an aero

generator. In 1974 NASA constructed and operated a wind

generator of 100kW capacity. In 1987 US firms generated a 2.5MW generator

CLASSIFICATION OF WIND TURBINES

1.Based on alignment of rotor axis

Horizontal axis turbine

Vertical axis turbine

2.Based on the force utilised

Lift type wind turbine

Drag type wind turbine• Forces are transmitted from a moving fluid to

an object in the flow stream Lift = the force component perpendicular to the original flow direction Drag = the force component in line with the original flow direction

α = low

α = medium<10 degrees

α = HighStall!!

DRAG TYPE

LIFT TYPE

DRAG TYPE LIFT TYPELow speed turbines High speed turbines

Rotor shaft torque is comparatively high.

Rotor shaft torque is comparatively low.

Greater blade area is required Aerofoil type blades are required to minimize the effect of drag forces

Blades are fabricated using curved plates

Blades are having high thickness to chord ratio to produce high lift

Small (10 kW)• Homes• Farms• Remote Applications (e.g. water

pumping, telecom sites)

Large (250 kW - 2+MW)

• Central Station Wind Farms

• Distributed Power

Intermediate (10-250 kW)• Village Power• Hybrid Systems• Distributed

Power

KidWind Project | www.kidwind.org

3. Based on generation

WIND TURBINE-MAINCOMPONENTS

DIFFERENT TYPES OF ROTORS

Multiblade Type

Propeller Type

Savonious Type

Darrieus type

MULTIBLADE TYPE ROTOR

• Sheet metal blades.• Width of blade increases

outward.• Blade is fixed at inner and

outer end.• No. of blades 12-18.

PROPELLER TYPE

• 2 or 3 aerodynamic blades.• Blades made od fibre glass

reinforced plastic.• Diameter of rotor 2-25 m.

SAVONIOUS TYPE

• It has 2 or more identical hollow semi cylinders fixed to vertical axis.

• Rotor rotates due to pressure difference

• Driving torque is drag type, so large starting torque.

• Suitable for water pumping.

DARRIEUS TYPE

• 2 or 3 thin curved blades.• Both end of blade attached to

vertical shaft.• Operates for wind from any

direction.• Driving force is lift torque.• Used for electricity generation.

IMPORTANT TERMS RELATED TO WIND TURBINE

• Rotor• Blades• Hub• Propeller

• Leading edge• Trailing edge• Chord line

Aerofoil shape of blade

• Mean line• Angle of attack • Pitch angle

WIND ENERGY EXTRACTION

Extract energy from wind stream by converting the KE of wind to rotational motion required to operate an electric generator.

On interaction of free wind on turbine rotor, the wind

transfers part of energy into rotor and speed of wind reduces.

AERODYNAMIC OPERATION OF WIND TURBINEAirfoil:-Cross section of wind turbine blades

Lift:-Pressure difference between top and the bottom surface of blade result in a force called aerodynamic lift that cause airfoil to rise. This lift cause rotation of blade about the hub

Drag:-A Force perpendicular to lift force also act on blades which impede the blade rotation .this force is called drag force.

WIND POWERPower in the Wind = ½ρAV3

Effect of air density, Effect of swept area, AEffect of wind speed, V

Swept Area: A = πR2 Area of the circle swept by the rotor (m2).

R

• Wind power would increase four times if rotor diameter is doubled.

• Wind power increases eight times if wind speed is doubled.

OFFSHORE TURBINES

More wind speeds

Less noise pollution

Less visual impact

Difficult to install and maintain

Energy losses due long distance transport

TURBINE DESIGN AND CONSTRUCTIONA Typical HAWT

Blades: Important part that extract wind EnergyLight weight and good strengthFabricated with aircraft industry technique.Made of Fiberglass reinforced polyester Structured for creating optimum lift.Rotor: Combination of blade and hub assemblyPitch control of blades: A system where the pitch angle of blade changes according to the wind speed for efficient operationBrakes: Aerodynamic and Mechanical braking are used for over speed protection , speed control , power control and emergency stop.Low speed shaft: shaft connected directly to rotor to the gear.

Gear box: Mechanical power generated by rotor blade is

transmitted to the generator through two stage gear box Provided for increasing shaft speed.Generator: Used for converting mechanical power to electric

power. Commonly used generators are PMSG,SEIG,DFIG.Controller: Microprocessor based controller monitor wind speed ,

direction of wind , power output and take proper yaw , pitch rotations.

Anemometer & wind wane: Used for wind speed and direction monitoring.Nacelle: Housing of generator, the gear box, yawing

mechanism,etc.

High speed shaft: Shaft connected between gear box and generatorYaw drive and yaw motor : Yawing is done using two yawing motors meshed with big toothed wheel mounted on tower. Yaw control continuously tracks and keep rotor axis in

wind direction. At high wind machine is stopped by turning the rotor

axis right angle to wind direction.

Tower: Modern turbine are mounted on tubular towers

MODES OF WIND POWER GENERATION

1) Standalone mode

2) Backup mode like wind diesel

3) Grid connected mode

STANDALONE MODE

Decentralized application of wind energy Individual consumer install their own wind turbineUsed for powering domestic appliances battery

charging, water pump etc.Capacity ranges between 2.5—5KwMost suited for remote mountainous areas.

BACK UP MODE LIKE WIND-DIESEL

DG is used for maintaining 24 hrs. power supply ,since wind power is intermitted

Used in areas ina ccessible to grid,hosptals,miltary installations

GRID CONNECTED WIND TURBINE GENERATORS

Generated power is distributed among nearby customers and excess power exported to grid.

Electric energy is purchased from grid when there is no wind

WIND POWER GENERATION CURVE

Cut in Speed: It is the wind speed(14m/s) at which the turbine output begins.

Rated Speed: It is the Speed at which the turbine is designed to generate rated power

Cut out Speed: When the speed reaches upper limit (25m/s) the turbine stops to generate power

WIND RESOURCE ASSESSMENT IN INDIA

Renewable source of energy

Free of fuel cost

Supply power to remote areas

Public opinion is in favor of wind power generation rather than nuclear generation

Cost effective

Economically competitive with other modes of generation

Reliable and has been used for ages

DISADVANTAGES OF WIND ENERGY SYSTEM

Low energy density.

Available at selected graphical location.

Wind speed being variable , wind energy is irregular.

Wind turbine design is complex.

Requires storage batteries which contribute environmental pollution.

Capital intensive.

REFERENCES

1. Renewable Energy Sources And Emerging Technologies, D.P Kothari,K.C Singal,Rakesh Ranjan

2. .3. www.renewableenergyworld.com.

THANK YOU