This document provides an overview of wind turbine engineering. It discusses key concepts such as how wind power depends on air volume, velocity, mass, and flux. It explains that turbine power output is a function of air density, wind velocity cubed, and rotor swept area. The Betz limit establishes that the maximum possible power coefficient for a conventional wind turbine is 59% efficiency. The document also outlines the major subsystems of a wind turbine and important design considerations such as aerodynamics, structures, control systems, and costs. Key parameters that must be chosen for a wind turbine design are also summarized.

1. Overview of Wind Turbine
Engineering
Eshan ahuja
eshanahuja1322@gmail.com
Dr. Navin Kumar Kohli

2. Wind Power
Wind Power depends on:
• amount of air (volume)
• speed of air (velocity)
• mass of air (density) A
• flowing through the area of interest (flux)
Kinetic energy
KE = ½ * m * v2 & Power is KE
• P = ½ * m * v 2
• Fluid mechanics gives mass flow rate(density * volume flux):
• dm/dt = ρ* A * v

3. Efficiency in Wind Power
Betz Limit & Power Coefficient:
• Power Coefficient, Cp, is the ratio of power extracted by the turbine to
the total contained in the wind resource Cp = PT/PW.
• Turbine power output PT = ½ * ρ * A * v 3 * Cp
• The Betz Limit is the maximal possible Cp = 16/27
• 59% efficiency is the BEST a conventional wind turbine can do in
extracting power from the wind

4. Power ~ cube of velocity
Power ~ air density
Power ~ rotor swept area A= πr²

5. Power Curve of Wind Turbine
• Capacity Factor (CF):
• • The fraction of the year the turbine generator is
operating at
• rated (peak) power
• Capacity Factor = Average Output / Peak Output
≈ 30%
• • CF is based on both the characteristics of the
turbine and the
• site characteristics (typically 0.3 or above for a
good site)

6. Wind Turbine Subsystems

7. Wind Turbine Subsystems
•– Foundation
•– Tower
•– Nacelle
•– Hub & Rotor
•– Drivetrain
•– Gearbox
•– Generator
•– Electronics & Controls
•– Yaw
•– Pitch
•– Braking
•– Power Electronics
•– Cooling
•– Diagnostics

8. Wind Turbine Design issues
Aerodynamics
Structures,
Structural Dynamics,
Vibrations, Stability,
Fatigue Life
Control systems for
RPM, Pitch, Yaw
Transmission,
gears, tower,
power systems,
etc.
Cost
Noise,
aesthetics

9. Parameters to be Chosen
• We need to decide on
– Number of blades
– Blade planform (i.e. how does chord vary with
radius)?
– Blade radius
– Blade twist distribution
– Airfoils
– RPM
– Decisions about variable RPM, variable pitch
• We need to consider cost, noise, vibrations,
fatigue, etc as well.

10. Benefits of Wind Energy
• Renewable
• Emits no pollutants
• No foreign dependence
• Wind is free & plentiful
• Cost effective
• Take up less space than conventional power
plants

11. Conclusions
• Wind Energy is renewable & emits no pollution
•Wind speed increases significantly with height
•The power in the wind varies with the cube of wind speed
•The Betz theory establishes a limit of 16/27=0.59 to power coefficient
•The wind turbine blade is an aerofoil
•The tip speed is greater than the wind speed
•Lift is created as the blade slices through the wind –the tangential
component of the lift is what drives the turbine
•In India the rate of wind power is very competitive around Rs 4.5/kWh

12. thank you
eshan ahuja,
Australian National University,
Australia