The document discusses wind turbines and wind energy. It covers the basic principles of how wind turbines work by converting kinetic energy from the wind into mechanical power. Specifically, it discusses how factors like swept area, wind speed, air density, rotor solidity, airfoil shape, number of blades, and blade composition and manufacturing can affect a wind turbine's efficiency and power output. The document also lists some advantages of wind energy like being renewable and producing no emissions, as well as disadvantages like intermittency of wind and potential noise issues.

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.