Civil engineering

1. SShhrreeee SSwwaammii AAttmmaannaanndd SSaarraasswwaattii
IInnssttiittuuttee ooff TTeecchhnnoollooggyy

2. Introduction
• Wind power is good renewable, clean and free
source of energy for power production.
• Reduce dependence on fossil fuels including
imported oils.
• Reduce emission of greenhouse gas and other
pollutant.
• One major concern is the noise – can be
improved.
• Intermittency and variability of the wind.

5. Wind Turbine Power and Efficiency
All wind power cannot be captured by rotor or air would be
completely still behind rotor and not allow more wind to pass
through.
A wind turbine converts a fraction of the wind energy into
mechanical energy.
A part is transferred to the rotor of the wind turbine.
The efficiency is the ratio of actual power developed by wind
turbine rotor to the available wind power.
Theoretical limit of rotor
efficiency is 59%.
Most modern wind turbines
are in the 35 – 45% range.

6. Power in the Wind = ½ρAV3
– Effect of swept area, A
– Effect of wind speed, V
– Effect of air density, r
R
Swept Area: A = πR2 Area of the
circle swept by the rotor (m2).

7. Rotor
Solidity is the ratio of total rotor plan
form area to total swept area
Low solidity (0.10) = high speed, low torque
High solidity (>0.80) = low speed, high torque
A
R
a

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

9. Types of Wind Turbine
Horizontal axis
- Primarily of the axial flow types
- requires control mechanism to take
account of variation in wind direction
e.g Savonius wind turbine
Vertical axis
- Can handle winds from all directions
e.g Darrieus wind turbine

11. Number of Blades - Two
• Need teetering hub
and or shock
absorbers because of
gyroscopic imbalances.
• Capture 5% less
energy than three
blade designs.

12. Number of Blades - Three
• Balance of gyroscopic
forces.
• Slower rotation
– increases gearbox &
transmission costs
– More aesthetic, less noise,
fewer bird strikes.
• Mostly used in india
three bladed wind mill.

13. Blade Composition Metal
• Steel
– Heavy & expensive
• Aluminum
– Lighter-weight and
easy to work with
– Expensive
– Subject to metal fatigue

14. Blade Fiberglass
• Lightweight, strong,
inexpensive, good
fatigue characteristics.
• Variety of
manufacturing
processes
• Most modern large
turbines use fiberglass.

15. Manufacturing of Blade

16. Pitch Control Mechanisms

17. Advantages of Wind Energy
 Wind is free, wind farms need no fuel.
 Produces no waste or greenhouse gases.
 A good method of supplying energy to remote areas.
 Although wind turbines can be very tall, they only take up a
small plot of land.
 Wind farms are appealing to the landscape.
 Remote areas that have no other energy source available can
use wind turbines to produce their own supply.

18. Disadvantages of Wind Energy
The amount of wind available always varies.
There will be times when they produce no
electricity at all.
Wind turbines can be noisy. It can be equivalent
to the noise of a car traveling at 70 mph.
Because wind turbines have to be anchored to the
ground this could possibly impact soil structure.
They do not produce enough electricity to power
large amounts of homes.