How do Wind Turbines Work?
Summary
TLDRThis script explores the concept of wind as moving air, its creation due to uneven heating of Earth's surface, and its historical use in windmills and ships. It delves into modern wind turbines, explaining how they convert wind's kinetic energy into electricity. The script details the parts of a turbine, their functions, and the physics behind energy conversion, emphasizing wind's advantages as a renewable, low-impact energy source.
Takeaways
- 📝 Wind is the movement of air, caused by the uneven heating of the Earth's surface by the Sun.
- 💻 Historically, people have harnessed wind energy for over 5000 years, starting with the ancient Egyptians using wind to sail ships.
- 💵 Windmills were initially used for grinding grains and have evolved into modern wind turbines that generate electricity.
- 💲 Wind turbines convert the kinetic energy of wind into electrical energy and come in various sizes for different applications.
- 💴 Large wind turbines, known as wind farms, are a significant source of renewable energy and are used to reduce reliance on fossil fuels.
- 💰 Wind energy has the lowest relative greenhouse gas emissions, least water consumption, and favorable social and economic impacts compared to other energy sources.
- 💵 The main parts of a wind turbine include blades, rotor, tower, pitch mechanism, low-speed shaft, high-speed shaft, gearbox, generator, brake, anemometer, controller, and yaw drive.
- 💲 The blades of a wind turbine have a wing-like profile that generates lift when pitched into the wind, capturing energy efficiently.
- 💰 The gearbox increases the rotational speed from the low-speed shaft to the high-speed shaft, which is necessary for the generator to produce electricity.
- 💴 The pitch mechanism adjusts the angle of the blades to control the rotor speed and prevent damage in high winds.
- 💲 According to Betz's law, no wind turbine can capture more than 59.3% of the kinetic energy in the wind, as extracting more would require the wind speed downstream of the turbine to be zero, which is impossible.
Q & A
What is wind?
-Wind is moving air, which is invisible but can be observed through its effects on objects like leaves, grass, flags, and laundry on a clothesline.
How is wind created?
-Wind is created by the uneven heating of the Earth's surface by the Sun, as different types of land and water absorb heat at different rates.
How have people used wind energy historically?
-Ancient Egyptians used wind to sail ships on the Nile River over 5000 years ago. Later, windmills were built to grind grains, and in Holland, they improved windmills with propeller-type blades.
What are the modern uses of wind energy?
-Modern uses include wind turbines that convert wind's kinetic energy into electrical energy, used for applications like battery charging, domestic power supply, and large-scale electricity generation in wind farms.
What are the environmental benefits of wind energy compared to other energy sources?
-Wind energy has the lowest relative greenhouse gas emissions, the least water consumption, and the most favorable social economics compared to photovoltaic, hydro, geothermal, coal, and gas.
What are the main parts of a wind turbine?
-The main parts include the blades, rotor, tower, pitch mechanism, low-speed shaft, high-speed shaft, gearbox, generator, brake, anemometer, controller, and yaw drive.
How do wind turbine blades generate electricity?
-The blades have a wing profile that generates lift when the wind blows over them, causing the rotor to spin and the generator to produce electricity.
Why do wind turbine blades need to be pitched?
-Pitching the blades adjusts them into the wind to control the rotor speed and prevent damage from winds that are too high or too low to produce electricity efficiently.
What is the role of the tower in a wind turbine?
-The tower, made from tubular steel, concrete, or steel lattice, supports the turbine structure and allows it to capture more energy from higher wind speeds at greater heights.
How does a wind turbine convert wind energy into electrical energy?
-The wind turns the blades, which spin the rotor connected to a generator. The generator then converts the mechanical energy into electrical energy.
What is Betz's law and what does it state about wind turbines?
-Betz's law states that no turbine can capture more than 59.3% (or 16/27ths) of the kinetic energy in the wind. As the wind turbine extracts more energy, the wind is slowed down.
How do wind turbines measure and respond to changes in wind speed and direction?
-Anemometers measure wind speed, and wind vanes measure wind direction. This data is sent to a controller, which adjusts the yaw mechanism to orient the turbine with respect to the wind and the pitch mechanism to control rotor speed.
Outlines
🌬️ Understanding Wind and Wind Energy
Wind is the movement of air, which is invisible but can be observed through its effects on objects like leaves, grass, flags, and laundry. It is created by the uneven heating of the Earth's surface by the Sun, leading to air motion. Historically, wind has been harnessed for sailing and milling grains, with the Dutch improving windmill design. Modern applications include wind turbines that convert wind's kinetic energy into electricity. These turbines come in various sizes and are part of wind farms that contribute to renewable energy strategies, reducing reliance on fossil fuels. The script explains the components of a wind turbine, including blades, rotor, tower, pitch system, low and high-speed shafts, gearbox, generator, brake, anemometer, and yaw drive, and how they work together to generate electricity.
💡 The Mechanics of Wind Turbines
Wind turbine blades are designed with an aerodynamic profile similar to airplane wings, which generates lift when pitched correctly into the wind. The airflow direction is a combination of the wind and the rotation-induced airflow. The blade tips can reach high radial velocities, necessitating a twist to maintain the optimal angle of attack for energy capture. The slow rotation speed of the blades is increased by a gearbox to generate electricity. A brake system is included to prevent damage from high winds. The electricity is transmitted through cables to a transformer at the tower's base. Wind direction is monitored by an anemometer and wind vane, with a yaw system ensuring the turbine faces the wind for maximum efficiency. The pitch system adjusts the blades to maintain alignment with wind changes. Betz's law is introduced, stating that no turbine can capture more than 59.3% of the wind's kinetic energy, as extracting more would require the wind speed downstream of the turbine to be zero, which is impossible.
🔢 Betz's Law and Wind Energy Conversion
This paragraph concludes the discussion on Betz's law, which limits the maximum theoretical efficiency of a wind turbine to 59.3%. It explains that as a turbine extracts kinetic energy from the wind, the wind speed downstream of the turbine decreases. The law is proven by calculating the power extracted from the wind and comparing it to the power in the undisturbed wind. The maximum power extraction occurs when the downstream wind speed is one-third of the upstream speed.
Mindmap
Keywords
💡Wind
💡Wind Energy
💡Windmill
💡Wind Turbine
💡Renewable Energy
💡Pitch System
💡Generator
💡Gearbox
💡Anemometer
💡Yaw System
💡Betz's Law
Highlights
Wind is air in motion caused by the uneven heating of the Earth's surface by the Sun.
Ancient Egyptians used wind to sail ships on the Nile River over 5000 years ago.
Windmills were later built to grind wheat and other grains, resembling paddle wheels.
Holland improved windmills with propeller-type blades made with sails.
Windmills in the US were used for grinding wheat, pumping water, and cutting wood.
Modern wind turbines convert wind's kinetic energy into electrical energy.
Wind turbines come in various sizes for different applications, from battery charging to power supply.
Wind farms are significant sources of renewable energy, reducing reliance on fossil fuels.
Wind energy has the lowest greenhouse gas emissions and least water consumption among energy sources.
The main parts of a wind turbine include blades, rotor, tower, pitch system, and generator.
Wind turbine blades have a wing profile similar to airplanes to generate lift.
The tower of a wind turbine is made from tubular steel, concrete, or steel lattice.
Wind speed increases with height, so taller towers can capture more energy.
The pitch system controls the angle of the blades to optimize energy capture and protect from high winds.
The generator produces 60 cycle AC electricity, typically using an induction generator.
The brake system stops the turbine mechanically, electrically, or hydraulically in emergencies.
An anemometer measures wind speed, and a wind vane measures wind direction for the turbine's orientation.
Betz's law states that no turbine can capture more than 59.3% of the kinetic energy in the wind.
Wind turbines operate most efficiently when aligned with the wind direction.
The efficiency of a wind turbine is measured by comparing upstream and downstream wind speeds.
Transcripts
[Music]
what is wind wind is moving air although
you can't see the wind is so you can see
how its force affects things in its path
leaves grass Flags laundry on a
clothesline
even your hair on a windy day how wind
is created wind is simply air in motion
it is caused by the uneven heating of
the Earth's surface by the Sun because
the Earth's surface is made from very
different types of land and water
it absorbs the Sun heats at different
rates
one example of this uneven heating can
be found in the daily wind cycle
since ancient times people have
harnessed the winds energy over 5000
years ago the ancient Egyptians use the
wind to sail ships on the Nile River
later people build windmills to grind
wheat than other grains the early
windmills look like paddle wheels
centuries later the people in Holland
improved the windmill they gave a
propeller type of blades still made with
sails Holland is famous for its
windmills in this country the colonists
used windmills to grind wheat and corn
to pump water and to cut wood sawmills
today people occasionally use windmills
to grind grain mhmm water but they also
use modern wind turbines to make
electricity a wind turbine is a device
that converts the winds kinetic energy
into electrical energy wind turbines are
manufactured in a wide range of vertical
and horizontal access types the smallest
turbines are used for applications such
as battery charging for power for boats
or caravans or to power traffic warning
signs slightly larger turbines can be
used for making contributions to a
domestic power supply while selling
unused power back to the utility
supplier via the electrical grid a raise
of large turbines known as wind farms
are becoming increasingly important
source of intermittent renewable energy
and are used by many countries as part
of a strategy to reduce their reliance
on fossil fuels window is shown to have
the lowest relative greenhouse gas
emissions the least water consumption
demands and the most favorable social
economics compared to photovoltaic hydro
geothermal coal and gas
let's see the main parts of the wind
turbine blades blades lift some rotates
when the wind is blown over them causing
the rotors to spin rotor blades and hub
together form the rotor tower tower made
from tubular steel concrete or steel
lattice supports the structure of the
turbine because of wind speed increases
with height taller tower was unable to
or bias the capture more energy and
generate more electricity
pitch turns or pictures blades out of
the wind to control the road to speed
and to keep the rotor from turning in
winds that are too high or too low to
produce electricity lowest speed shaft
turns as those beat shaft at about 30 to
60 revolutions per minute
high speed shaft drives the generator
gearbox connects the low-speed shaft to
the high speed shaft and increases the
rotational speeds from about thirty to
sixty rotations per minute to about 1000
to 1800 rpm
this is the rotational speed required by
most generators to produce electricity
generator generates a producer 60 cycle
AC electricity it is usually an
off-the-shelf induction generator
brake brake stops or motor mechanically
electrically or hydraulically in
emergencies
anemometer measures the weed speed and
transmits wind speed data to the
controller controller controller start
up the Machine and wind speeds up to
about 8 to 60 miles per hour and shuts
off the machine at about 55 miles per
hour turbines to not operate our wind
speeds above about 55 miles per hour
because they may be damaged by the high
winds wind vane measures wind direction
and communicates with the yaw Drive to
orient the turbine properly with respect
to the wind your drive Orient's up wind
turbines to keep them facing when wind
direction changes down wind turbines
don't require your drive because the
wind manually blows the rotor away from
its your motor powers the yaw Drive
how the wind turbine is working let's
see the basic working when the wind is
blowing the blades are turned the rotor
is connected to the generator while it
rotates the rotator generator produces
the electricity let's get deep into the
functioning of each parts and how the
wind energy turns into electrical energy
first we will see the wind blades the
blades having the wing profile like the
airplanes the shape of the blade what
makes the wind turbines to rotate but
only if the angle of attack is right by
pitching the blade into the wind
the blade generates lift the direction
of the airflow is the combination of the
wind and the airflow caused by the
rotation of the rotor near the blade
root the radial velocity of the blade is
low but on the tip of the blade the
radial velocity of the turbine is as
high as 18 m/s this is why the tip of
the blade twisted into the direction of
the airflow ensures the right angle of
attack to harvest as much energy from
the wind as possible the wind turbine
blades typically turn at a very low rate
of rpm due to the issues of the noise in
mechanical strength at this level of
rotation we cannot produce any
meaningful electricity from a generator
we have to increase the speed of the
rotation of the generator so this setup
used by planetary gearbox to achieve a
maximum speed if wind is blowing our
high speed turbine may damage so the
brake system is placed to control the
over speed in windy days
electricity produced from the generator
passed through a cable towards the
bottom of the tower where the step-up
transformer is situated
the wind turbine should face toward the
wind for maximum power generation but
wind can change its direction at any
time anemometer and wind vane is located
at the top of the nacelle
it measures the wind speed and direction
if any changes in the wind direction it
sends to the controller the control
system controls the your mechanism to
rotate the nacelle with the help of the
your motor so the wind turbine can
always aligned with the winds direction
velocity also changing in the blades due
to the wind speed so blade tilting
mechanism is located at the rotor this
is called pitch system it tilts the
blades at corresponding direction with
proper alignment to ensure velocity to
check the efficiency of the wind turbine
measure the wind speed at upstream and
downstream over a wind turbine the wind
speed of downstream is much smaller than
the upstream this is because the blades
absorb some kinetic energy from the wind
the same amount of energy is converted
as mechanical power of the wind turbine
a wind turbine absorbs a 100 percent of
the available kinetic energy only if the
downstream wind becomes zero
however zero wind speed are downstream
is physically impossible condition
now let's see what is Betts's law about
the wind turbine according to Betsy's
law no turbine can capture more than 16
twenty-seventh that is 59.3%
of the kinetic energy and wind the more
kinetic energy our wind turbine pulls
out of the wind the more the wind will
be slowed down as it leaves this is
called Betts's law let's prove this
theory let's assume the average wind
speed through the rotor area is the
average of the undisturbed wind speed
before the wind turbine chord is v1
and the wind speed after the passage
through the rotor playing chord as V 2
that is V 1 plus V 2 divided by 2
the mass of the air streaming through
the rotor during one second is equal to
the multiplication of the density of
their swept area around the drove the
average wind speed through the rotor
area according to Newton's second law
power extracted from the wind by the
rotor is equal to the mass times the
drop in the wind speed squared
substituting em into this expression
from the first equation we get the
following expression for the power
extracted from the wind now let us
compare our results with the total power
in the undisturbed wind streaming
through exactly the same area F with no
rotor blocking the wind be cool this
power p0 the ratio between the power we
extract from the wind and the power in
the undisturbed wind is then P divided
by p0 equals 1 over 2 times 1 minus v2
divided by v1 all squared times 1 plus
v2 over v1
we may plot P divided by p0 as a
function of V 2 divided by V 1
we can see that the function reaches its
maximum for v2 divided by v1 equals one
third
and that the maximum value for the power
extracted from the wind is zero point
five nine or sixteen over twenty-seven
of the total power in the wind
5.0 / 5 (0 votes)