Wind Turbines

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https://pursuitengineering.blogspot.com/2017/02/wind-turbines.html A wind turbine works the opposite of a fan. Instead of using electricity to make wind, like a fan, wind turbines use wind to make electricity. The wind turns the blades, which spin a shaft, which connects to a generator and makes electricity. Wind turbines are classified into two general types: horizontal axis and vertical axis. A horizontal axis machine has its blades rotating on an axis parallel to the ground. A vertical axis machine has its blades rotating on an axis perpendicular to the ground. There are a number of available designs for both and each type has certain advantages and disadvantages. However, compared with the horizontal axis type, very few vertical axis machines are available commercially.

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Wind Turbines https://pursuitengineering.blogspot.com/2017/02/wind-turbines.html:

Wind Turbines https://pursuitengineering.blogspot.com/2017/02/wind-turbines.html

Slide 2:

A wind turbine works the opposite of a fan wind turbines use wind to make electricity. The wind turns the blades, which spin a shaft, which connects to a generator and makes electricity. Wind turbines convert the kinetic energy in the wind into mechanical power. This mechanical power can be used for specific tasks (such as grinding grain or pumping water) or a generator can convert this mechanical power into electricity . If the mechanical energy is then converted to electricity, the machine is called a wind generator.

Types of Wind Turbines :

Types of Wind Turbines Wind turbines are classified into two general types H orizontal axis Vertical axis A horizontal axis machine has its blades rotating on an axis parallel to the ground A vertical axis machine has its blades rotating on an axis perpendicular to the ground

Horizontal-axis wind turbines (HAWT):

Horizontal-axis wind turbines (HAWT) Theses wind turbines typically either have two or three blades. These three-bladed wind turbines are operated "upwind," with the blades facing into the wind.

Horizontal-axis wind turbines (HAWT):

Horizontal-axis wind turbines (HAWT) Up-Wind Turbines Some wind turbines are designed to operate in an upwind mode (with the blades upwind of the tower). Large wind turbines use a motor-driven mechanism that turns the machine in response to a wind direc­tion. Smaller wind turbines use a tail vane to keep the blades facing into the wind

Horizontal-axis wind turbines (HAWT):

Horizontal-axis wind turbines (HAWT) Down-Wind Turbines   Other wind turbines operate in a downwind mode so that the wind passes the tower before striking the blades. Without a tail vane, the machine rotor naturally tracks the wind in a downwind mode.

Horizontal-axis wind turbines (HAWT):

Horizontal-axis wind turbines (HAWT) Shrouded Wind Turbines   Some turbines have an added structural design feature called an augmentor . The augmentor is intended to increase the amount of wind passing through the blades.  

Vertical-axis wind turbines (VAWT) :

Vertical-axis wind turbines (VAWT)

Vertical-axis wind turbines (VAWT) :

Vertical-axis wind turbines (VAWT) Savonius Wind Turbine   The Savonius turbine is S-shaped if viewed from above. This drag-type VAWT turns relatively slowly, but yields a high torque. It is useful for grinding grain, pumping water, and many other tasks, but its slow rotational speeds make it unsuitable for generating electricity on a large-scale

Vertical-axis wind turbines (VAWT) :

Vertical-axis wind turbines (VAWT) Flapping Panel Wind Turbine   This illustration shows the wind coming from one direction, but the wind can actually come from any direction and the wind turbine will work the same way

Vertical-axis wind turbines (VAWT) :

Vertical-axis wind turbines (VAWT) Darrieus Wind Turbine   The Darrieus turbine is the most famous vertical axis wind turbone . It is characterized by its C-shaped rotor blades which give it its eggbeater appear­ance. It is normally built with two or three blades.  

Vertical-axis wind turbines (VAWT) :

Vertical-axis wind turbines (VAWT) Giromill Wind Turbine   The giromill is typically powered by two or three vertical aerofoil’s attached to the central mast by horizontal supports. Giromill turbines work well in turbulent wind conditions and are an affordable option where a standard horizontal axis windmill type turbine is unsuitable

Parts of a Wind Turbine:

Parts of a Wind Turbine The nacelle contains the key components of the wind turbine, including the gearbox, and the electrical generator.   The tower of the wind turbine carries the nacelle and the rotor. Generally, it is an advantage to have a high tower, since wind speeds increase farther away from the ground. The rotor blades capture wind energy and transfer its power to the rotor hub. The generator converts the mechanical energy of the rotating shaft to electrical energy The gearbox increases the rotational speed of the shaft for the generator

Installing a Wind Turbine :

Installing a Wind Turbine The basic steps for installing a small wind turbine on your property are : Determine whether the wind resource in your area makes a small wind system economical. Determine your household electricity needs by checking your monthly or yearly electricity usage. Find out whether local zoning ordinances allow wind turbine installations. Purchase and install a wind turbine sized to the needs of your household.

Siting a Wind Farm :

Siting a Wind Farm   Winds Minimum class 4 desired for utility-scale wind farm (>7 m/s at hub height) Transmission Distance, voltage excess capacity Permit approval Land-use compatibility Public acceptance Visual, noise, and bird impacts are biggest concern Land area Economies of scale in construction Number of landowners  

Advantages of Wind Power :

Advantages of Wind Power Environmental Economic Development Fuel Diversity & Conservation Cost Stability small project size Short/flexible development time Dispatch ability

Disadvantages :

Disadvantages Generally remote location Grid connectivity -- lack of transmission capability Intermittent output only when the wind blows Low capacity factor Birds of Prey (hawks, owls, golden eagles) in jeopardy Shutting down all the turbines for at least two months each winter Replace all before permits expire in 13 y ears

Wind Energy and Power :

Wind Energy and Power   Atmospheric pressure differences accelerate and impart kinetic energy into the air Wind energy conversion machines (WEC) convert wind energy into electrical or mechanical forms      

How much power can we extract? :

How much power can we extract?

Wind Energy Natural Characteristics :

Wind Energy Natural Characteristics Wind Speed Wind energy increases with the cube of the wind speed 10 % increase in wind speed translates into 30% more electricity 2X the wind speed translates into 8X the electricity Wind energy increases with height to the 1/7 power 2X the height translates into 10.4% more electricity  

Slide 23:

Air density Wind energy increases proportionally with air density Humid climates have greater air density than dry climates Lower elevations have greater air density than higher elevations Wind energy in Denver about 6% less than at sea level Blade swept area Wind energy increases proportionally with swept area of the blades

Slide 24:

Blades are shaped like airplane wings 10 % increase in swept diameter translates into 21% greater swept area Longest blades up to 413 feet in diameter, resulting in 600 foot total height   Height Wind energy increases with height to the 1/7 power 2X the height translates into 10.4% more electricity

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