The document discusses various aspects of wind energy and wind turbines. It begins by noting that energy plays a vital role in our lives and discusses different energy resources including fossil fuels and renewable sources like wind. It then provides details on the history of wind energy use dating back thousands of years, as well as modern wind turbine design and components. The document discusses how wind turbines work, including blade design principles, optimal tip speed ratios, and cut-in, rated, and cut-out wind speeds. It also addresses wind farm installation and the advantages of wind power as a renewable and non-polluting energy source.

1. 7/6/2015
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2. Energy
• Energy plays a vital role in our life

3. Energy
resources
Fossile fuel
Petroleum
coal
natural gas
Renewable
biomass
hydro
wind
solar
marine energy
sources.
Nuclear uranium

4. Where Do We Get Our Energy?

6. FUEL
• The generation of electricity is the single largest use of fuel in the world.
• More than 60 % of power generated comes from fossil fuels
Transportation Power Generation
Fuels are required for a variety of purposes ,but are
utilized chiefly for..

7. BUT, Twin Crises Of Fossil Fuel:
Depletion And Environmental Degradation
Fossil Fuels will soon
be Exhausted
Global warming

8. Can you imagine life without fuel?
NO!

9. Need to Change Perceptions…

10. What Makes Wind ??

11. 5000 BC
Sailboats used on
the Nile indicate
the power of wind
500-900 AD
First windmills
developed in
Persia
1300 AD
First horizontal-
axis
windmills in
Europe
1850s
Daniel Halladay and
John Burnham build
Halladay Windmill;
start US Wind
Engine Company
Late 1880s
Thomas O. Perry
conducted 5,000
wind experiments;
starts Aermotor
Company
1888
Charles F. Brush
used windmill to
generate electricity
in Cleveland, OH
Early 1900s
Windmills in CA
pumped saltwater
to evaporate ponds
1941
In VT, Grandpa’s
Knob turbine
supplies power to
town during WWII
1979
First wind turbine
rated over 1 MW
began operating
1985
CA wind capacity
exceeded 1,000 MW
1993
US WindPower developed
first commercial variable-
speed wind turbine
2004
Electricity from
wind generation
costs 3 to 4.5 cents
per kWh
2011
Wind power provided
over 12% of renewable
energy used in US
History of Wind Energy

12. Why Wind Energy?
• Clean, zero emissions
– - NOx, SO2, CO, CO2
– - Air quality, water quality
– - Climate change
• Reduce fossil fuel dependence
– - Energy independence
– - Domestic energy—national security
• Renewable
– - No fuel-price volatility

13. Renewable Electric Capacity Worldwide
US DOE, EERE 2012 Renewable Energy Data Book

14. China Leads the World in Wind Capacity-
Top 5 Countries for 2013
New Installed Capacity
1. China
2. Germany
3. United Kingdom
4. India
5. Canada
Total Installed Generating Capacity (MW)

15. Modern Wind Turbines
• Turbines can be categorized into two classes
based on the orientation of the rotor

16. •Vertical-AxisWindTurbines

17. •Vertical-AxiswindTurbines Advantages
o Omni-directional
- Accepts wind from any direction
o Components can be mounted at ground level
- Ease of service
- Lighter weight towers
o Can theoretically use less materials to capture the same
amount of wind
Disadvantages
o Rotors generally near ground where wind is poorer
o Poor self-starting capabilities
o Requires support at top of turbine rotor
o Requires entire rotor to be removed to replace bearings
o Overall poor performance and reliability

18. Horizontal -Axis wind Turbines
HAWA

19. Off-Shore Wind Farms

20. Many Different Rotors…

21. Types of Electricity Generating Wind Turbines
Small (10 kW)
• Homes
• Farms
• Remote Applications
(e.g. water pumping,
telecom sites,
icemaking)
Large (250 kW - 2+MW)
• Central Station Wind Farms
• Distributed Power
Intermediate
(10-250 kW)
• Village Power
• Hybrid Systems
• Distributed Power

26. Wind Turbine – Blade Design
• More blades give more torque, but slower speed, and most
alternators need fairly good speed to cut in.
• Wind turbines are built to catch the wind's kinetic (motion) energy.
• The ideal wind turbine design is not indicated by technology alone, but
by a combination of technology and economics.
• Wind turbine manufacturers wish to optimize their machines, so that
they deliver electricity at the lowest possible cost per kilowatt hour
(kWh) of energy.

27. Calculation of Wind Power
•Power in the wind
– Effect of swept area, A
– Effect of wind speed, V
– Effect of air density,  R
Swept Area: A = πR2
No other factor is more important to
the amount of power available in the
wind than the speed of the wind
Power in the Wind = ½ ρ A V3

28. Wind Turbine
Blade designs operate on the
principle of .
draglift

29. Lift & Drag Forces
• The Lift Force is
perpendicular to the
direction of motion. We want
to make this force BIG.
• The Drag Force is parallel
to the direction of motion.
We want to make this force
small.
α = low
α = medium
<10 degrees
α = High
Stall!!

30. 31
• For the drag design, the wind
pushes the blades out of the
way.
• Drag powered wind turbines
are characterized by slower
rotational speed and high
torque capability.
• They are useful for the
pumping, sawing or grinding
Drag Design

31. Wind Turbine Design using Drag Principle
32

32. • The blade is essentially an airfoil, or wing
• More efficient than drag device
• When air flows past the blade, a wind speed and
pressure differential is created between the upper
and lower blade surfaces.
• The pressure at the lower surface is greater and
thus acts to "lift" the blade.
• When blades are attached to a central axis, like a
wind turbine rotor, the lift is translated into
rotational motion.
• Lift-powered wind turbines have much higher
rotational speeds than drag types and therefore
are well suited for electricity generation.
LIFT Design

33. Airfoil Shape
Just like the wings of an airplane,
wind turbine blades use the
airfoil shape to create lift and
maximize efficiency.
The phenomena

34. • Angle of attack is the angle between the chord line of the
airfoil and the free stream direction .
• Angle of attack has a large effect on the lift generated by an airfoil.
Angle Of Attack (blade angle)

36. Twist & Taper
• Speed through the air of a point on the
blade changes with distance from hub
• Therefore, tip speed ratio varies as well
• To optimize angle of attack all along blade,
it must twist from root to tip
Fast
Faster
Fastest

37. Tip-Speed Ratio
• Tip-speed ratio is the ratio of the speed
of the rotating blade tip to the speed of
the free stream wind.
• There is an optimum angle of attack
which creates the highest lift to drag
ratio.
• Because angle of attack is dependant on
wind speed, there is an optimum tip-
speed ratio
ΩR
V
TSR =
Where,
Ω = rotational speed in radians /sec
R = Rotor Radius
V = Wind “Free Stream” Velocity
ΩR
R

38. Performance Over Range of Tip Speed Ratios
• Power Coefficient Varies with Tip Speed Ratio
• Characterized by Cp vs Tip Speed Ratio Curve

39. Tip Speed Ratio
CapacityFactor

40. Betz Limit
 All wind power cannot be
captured by rotor or air
would be completely still
behind rotor and not allow
more wind to pass through.
 Theoretical limit of rotor
efficiency is 59%
 Most modern wind turbines
are in the 35 – 45% range

41. Cut-in speed is the minimum wind speed at which the wind turbine
will generate usable power. This wind speed is typically between 2
and 3 m/s.
Wind Turbine
Cut-in Speed
-The rated speed is the minimum wind speed at which the wind
turbine will generate its design rated power.
- For example, a "10 kilowatt" wind turbine may not generate 10
kilowatts until wind speeds reach 12m/s.
- At wind speeds between cut-in and rated, the power output
from a wind turbine increases as the wind increases. The
output of most machines levels off above the rated speed.
Most manufacturers provide graphs, called "power curves,"
showing how their wind turbine output varies with wind speed.
Rated Speed

42. Wind Turbine
 At very high wind speeds, typically between 18 and 25 m/s, most
wind turbines cease power generation and shut down.
 The wind speed at which shut down occurs is called the cut-out
speed.
 Having a cut-out speed is a safety feature which protects the wind
turbine from damage.
 Shut down may occur in one of several ways.
 In some machines an automatic brake is activated by a wind
speed sensor.
 Some machines twist or "pitch" the blades to spill the wind.
Cut-out Speed
Wind Turbine

43. Rotor Solidity
Solidity :- is the ratio of
total rotor plan area to total swept area
 Low solidity (0.10) = high speed, low torque
 High solidity (> 0.80) = low speed, high torque
A
R
a
Solidity = 3a/A

44. Yawing – Facing the Wind
• Anemometer on nacelle tells controller
which way to point rotor into the wind
• Yaw drive turns gears to point rotor into
wind
• Passive Yaw (Most small turbines)
• Wind forces alone direct rotor
• Tail vanes
• Downwind turbines
• Active Yaw (all medium & large turbines produced
today, & some small turbines from Europe)

45. Blade Design
Blade Number
• The determination of the number of blades involves design
considerations of aerodynamic efficiency, component costs,
system reliability.
• Generally, the fewer the number of blades, the lower the
material and manufacturing costs will be.
• Higher rotational speed reduces the torques in the drive
train, resulting in lower gearbox and generator costs.

46.  Most common design is the three-bladed turbine.
 The most important reason is the stability of the
turbine.
A rotor with an odd number of rotor blades
(and at least three blades) can be considered to be
similar to a disc when calculating the dynamic
properties of the machine.
 A rotor with an even number of blades will give
stability problems for a machine with a stiff structure.
The reason is that at the very moment when the
uppermost blade bends backwards, because it gets the
maximum power from the wind, the lower most blade
passes into the wind shade in front of the tower.
Number of Blades

47. Wind Turbine – Blade Design
Ken Youssefi Engineering 10, SJSU
5-station design as seen from the tip
Blade size and shape Last profile next
to the hub
First profile at
the tip

48. Blade Composition

49. Advantages of Wind Power
•The wind blows day and night, which allows windmills to
produce electricity throughout the day. (Faster during the day)
•Energy output from a wind turbine will vary as the wind
varies, although the most rapid variations will to some extent
be compensated for by the inertia of the wind turbine rotor.
•Wind energy is a domestic.
• Renewable source of energy that generates no pollution and
has little environmental impact.

50. Advantages of Wind Power
• Up to 95 percent of land used for wind farms can also be
used for other profitable activities including ranching, farming
and forestry.
•The decreasing cost of wind power and the growing interest
in renewable energy sources should ensure that wind power
will become a valuable energy source in the worldwide.

51. SALWA ELSAYED