Basic principles, power in wind, force on blades & turbines, wind energy conversion, site selection, basic components of wind energy conversion systems (WECS), classification of WECS, wind energy collectors, applications of wind energy

1. DEPARTMENT OF CHEMICALENGINEERING
CHAPTER-5
“WIND ENERGY”
PROF. DEVARSHI P. TADVI
ASSISTANT PROFESSOR
CHEMICAL ENGINEERING
DEPARTMENT
S S AGRAWAL INSTITUTE OF
ENGINEERING & TECHNOLOGY,
NAVSARI

2. ENERGY?
• Energy: Ability to do work
• Energy Consumption: Amount of Energy used
• Energy Crisis: Energy Storage
• Energy Conversion: Energy Saftey
• Sources - Place (Root cause of something)
• Resources - Assets / material (Readily available to use)
• Wind - Flow of air around the earth

3. Nature of Wind
• The circulation of air in the atmosphere is caused
by the non-uniform heating of the earth’s surface
by the sun
• Wind speeds increase with height
• Air movement is affected by earth rotation
Wind Speed Remarks
Below 3 m/s Unsuitable for wind power system
3 – 4.5 m/s
May not reliable for wind power
systems

4. Factors affect the nature of the
wind:
1. Latitude of the place
2. Altitude of the place
3. Topography of the place
4. Scale of hours, month or year

5. WIND POWER - What is it?
• In laymen’s language, Wind possess kinetic energy Air is called wind
energy
• Air in motion is called wind.
• All renewable energy (except tidal and geothermal power),
ultimately comes from the sun
• The earth receives 1.74 x 1017 watts of power (per hour) from the sun
• About one or 2% of this energy is converted to wind energy
(which is about 50-100 times more than the energy converted to
biomass by all plants on earth).
• Differential heating of the earth’s surface and atmosphere
induces vertical and horizontal air currents that are affected
by the earth’s rotation and contours of the land WIND.
• e.g. : Land Sea Breeze Cycle.

6. • Winds are influenced by the ground surface at altitudes up to 100 meters.
• Wind is slowed by the surface roughness and obstacles.
•When dealing with wind energy, we are concerned with surface winds.
•A wind turbine obtains its power input by converting the force of the wind into
a torque (turning force) acting on the rotor blades.
•The amount of energy which the wind transfers to the rotor depends on the
density of the air, the rotor area and the wind speed.
•The kinetic energy of a moving body is proportional to its mass (or weight). The
kinetic energy in the wind thus depends on the density of the air, i.e. its mass per
unit of volume.
•In other words, the "heavier" the air, the more energy is received by the turbine.
•at 15° Celsius air weighs about 1.225 kg per cubic meter, but the density decreases
slightly with increasing humidity.

7. WINDMILL DESIGN
• A Windmill captures wind
energy and then uses a generator
to convert it to electrical
energy.
• The design of a windmill is an
integral part of how efficient it
will be.
• When designing a windmill, one
must decide on the size of the
turbine, and the size of the
generator.

8. Wind Turbines:
Number of Blades:
• 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
lowermost blade passes into the wind shade in front of the tower.

9. Orientation
Turbines can be categorized into two overarching
classes based on the orientation of the rotor
Vertical Axis Horizontal Axis

10. Vertical Axis Turbines
• Advantages
• Omnidirectional
– Accepts wind from any angle
• Components can be mounted at ground level
– Ease of service
– Lighter weight towers
• Can theoretically use less materials to capture the same
amount of wind
• Disadvantages
• Rotors generally near ground where wind poorer
• Centrifugal force stresses blades
• Poor self-starting capabilities
• Requires support at top of turbine rotor
• Requires entire rotor to be removed to replace bearings
• Overall poor performance and reliability
• Have never been commercially successful

11. Types of Electricity Generating Windmills
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

12. Wind Energy:
The Technology

14. Calculation of Wind Power
•PPowoweerrinintthheewwiinnddPower in the Wind = ½ρAV3
where,
 = Effect of air density,
A = Effect of swept area and
V = Effect of wind speed
Swept Area: A = πR2
Area of the circle swept
by the rotor (m2).

15. Importance of Wind Speed
• No other factor is more
important to the amount
of power available in the
wind than the speed of the
wind
• Power is a cubic function
of wind speed
– V X V X V
• 20% increase in wind
speed means 73% more
power
• Doubling wind speed
means 8 times more
power

16. Overspeed Protection: Furling

17. Early “WINDMILL” in Afghanistan (900AD)

19. Jacobs Turbine
(1920 – 1960)
Smith-Putnam Turbine
Vermont, 1940's

23. Off-Shore Windfarms

24. Middelgrunden

27. Site Selection of Wind Energy
Conversion System (WECS):
 Wind speed
 Turbine height
 Site cost
 Ground nature
 Local ecology
 Transportation
 Altitude of the site
 Nearness of the local user
 Environmental facts

28. Classification of Wind Energy
Conversion System (WECS):
I. Based on axis of rotation
a) Horizontal axis machines
b) Vertical Axis machines
II. Based on size
a) Small scale machines (upto 2kW)
b) Medium scale machines (2- 100kW)
c) Large scale machines (100kW and up to)

29. III. Based on the type of Output power
a) DC output
b) AC output
IV.Based on the rotational speed
a) Constant speed with variable pitch blades
b) Nearly constant speed with fixed pitch
blades
c) Variable speed with fixed pitch blades

30. V. Based on the utilization ofoutput
a) Battery storage
b) Direct connections to an
electromagnetic energy
converter
c) Interconnection with conventional electric
utility grid
d) Thermal potential storage

31. Component of Wind Energy
Conversion System (WECS):
• Main components :
 Tower
 Yaw control
 Rotors
 Gear box
 Generator
 Power regulation and controlling unit
 Safety system

37. Types of Wind Machines:
I. Horizontal/Axis wind machines
a) Horizontal/axis using two
aerodynamic blades
b) Horizontal/axis Propeller type using Single
blade
c) Horizontal/axis multi blade type
d) Horizontal/axis Dutch type
II. Vertical Axis windmachine
a) Savonius type
b) Darrieus type

41. Horizontal/Axis wind machines
• The axis of rotation is horizontal
• It consists of rotor, supporting structure, gear box,
generator
• Rotor blades made of metal or composite materials

45. Vertical Axis Wind Machines
• The axis of rotation is vertical
• Its also known as Cross wind axis machine
• No need of yaw control mechanism
• Heavy components placed on the ground

52. Wind
turbine
Gearing
Coupling
Electrical
generator
Controller
Yaw
Control
Pitch
Control
Wind
Speed
Control
Signal
Generator
temperature
To load
Utility
grid
Generating System

53. Advantages of Wind Power
• The wind blows day and night, which allows windmills to
produce electricity throughout the day. (Faster during the
day)
• Wind power is available in ample amounts in all coastal
areas.
• The decreasing cost of wind power and the growing interest in
renewable energy sources should ensure that wind power will
become a viable energy source worldwide.

54. Environmental advantages of wind power….
• It does not produce any carbon dioxide.
• It is a renewable energy.
• There is no use of fossil fuels.
• Almost 95% of the land in use can be used for
farming/recreational purpose.

55. Key Environmental
Issues facing
Wind Power

56. • Electro magnetic interference
• Noise
• Electric shock
• Throwing ice
• Tower collapse
• Damage occur in radio signals
• Blade failure
• Birds life

61. Avian Deat hs Per Year
1.5
7
67
75
100
174
500
0.000809106
0.001
100
0 100 500 600
1
200 300 400
A nu a lBird De aths(Mi l io ns)
G l a s W indows
ElectricTransmision
Line Co lisions
H o u s e c a t s
Hunting
Aut omobiles
Agriculture
Communicat ion Towers
OilandGasExtraction
Electrocution
WindTurbines
FACT:

62. Impacts of Wind Power:
Noise
• Modern turbines are
relatively quiet
• Rule of thumb – stay about 3x
hub-height away from houses

63. Attractiveness….
• Large windmills generate more electricity, but
move slowly and so have less attractiveness among
people.
• Small windmills( fast moving) have more
attractiveness but generate less electricity.

64. Tax Credits
• Whenever, tax incentives have been removed, interest
of investors has steeply decreased.
• Tax incentives increase government expenditure and lead
to fiscal deficit.

65. Capital cost….
• Capital cost of
installing a wind
turbine is very high.
• Land acquisitions by
the governments may
also create problems.

66. Thank You