Windmill Report

http://ia300119.us.archive.org/0/items/Wind_Farm_large_animate

Brief history Windmills have been around since the Middle Ages. The first recorded evidence of windmills being used for pumping water and grinding grain was in 7 AD in Persia. Then China got a hold of the idea and it spread to Asia, Africa, and the Mediterranean. The European mill appears to have developed independently from the others because the design is so different. The predecessor to our modern windmill dates back to France in 1105 and England in 1180. In the 14th century, the Dutch took windmills to a whole new level with their “tower” mills using canvas sails stretched across four wooden lattice frames like a big X. Their objective was moving enormous amounts of water into higher basins and canals. By the end of the 16th century thousands of windmills were pumping and grinding in western Europe. By the late 19th century, the count was 30,000—and, miraculously, there was still enough wind to go around.

history •

Wind machines were used for grinding grain in Persia as early as 200 B.C. This type of machine was introduced into the Roman Empire by 250 A.D. By the 14th century Dutch windmills were in use to drain areas of the Rhine River delta. In Denmark by 1900 there were about 2500 windmills for mechanical loads such as pumps and mills, producing an estimated combined peak power of about 30 MW. The first windmill for electricity production was built in Cleveland, Ohio by Charles F Brush in 1888, and in 1908 there were 72 wind-driven electric generators from 5 kW to 25 kW. The largest machines were on 24 m (79 ft) towers with four-bladed 23 m (75 ft) diameter rotors. Around the time of World War I, American windmill makers were producing 100,000 farm windmills each year, most for water-pumping.[1] By the 1930s windmills for electricity were common on farms, mostly in the United States where distribution systems had not yet been installed. In this period, high-tensile steel was cheap, and windmills were placed atop prefabricated open steel lattice towers.

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A forerunner of modern horizontal-axis wind generators was in service at Yalta, USSR in 1931. This was a 100 kW generator on a 30 m (100 ft) tower, connected to the local 6.3 kV distribution system. It was reported to have an annual load factor of 32 per cent, not much different from current wind machines.

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The first electricity producing windmill in the UK was created in the 1970's by Sir Henry Lawson-Tancred and was built by Ray Horner and Wilson (Widge) Conning in Boroughbridge near York in the North of England. It could create up to 100 kW of power and looked very much like the modern day turbines incorporating a three bladed propeller.

principles •

Transmission (mechanics)

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Using the principle of mechanical advantage, transmissions provide a torque-speed conversion (commonly known as "gear reduction" or "speed reduction") from a higher speed motor to a slower but more forceful output.

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Turbine design and construction

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Wind turbines are designed to exploit the wind energy that exists at a location. Aerodynamic modeling is used to determine the optimum tower height, control systems, number of blades, and blade shape.

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Virtually all modern wind turbines convert wind energy to electricity for energy distribution. As described, the modern wind turbine is a system that comprises three integral components with distinct disciplines of engineering science. The rotor component, which is approximately 20% of the wind turbine cost, includes the blades for converting wind energy to an intermediate low speed rotational energy. The generator component, which is approximately 34% of the wind turbine cost, includes the electrical generator, the control electronics, and most likely a gearbox component for converting the low speed rotational energy to electricity. The structural support component, which is approximately 15% of the wind turbine cost, includes the tower for optimally situating the rotor component to the wind energy source.[4]

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Special wind turbines –

Small wind turbines

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Small wind turbines may be as small as a four hundred watt generators for residential use. The small ones often have direct drive generators, direct current output, aeroelastic blades, lifetime bearings and use a vane to point into the wind. Larger, more costly turbines generally have geared power trains, alternating current output, flaps and are actively pointed into the wind. Direct drive generators and aeroelastic blades for large wind turbines are being researched.

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A small wind turbine can be installed on a roof. Installation issues then include the strength of the roof, vibration, and the turbulence caused by the roof ledge.

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(2 m) to 25 feet (8 m) in diameter and produce electricity at a rate of 900 watts to 10,000 watts at their tested wind speed. Some units are designed to be very lightweight, e.g. 16 kilograms (35 lb), allowing rapid response to wind gusts typical of urban settings and easy mounting much like a television antenna. It is claimed that they are inaudible even a few feet under the turbine. Dynamic braking regulates the speed by dumping excess energy, so that the turbine continues to produce electricity even in high winds. The dynamic braking resistor may be installed inside the building to provide heat (during high winds when more heat is lost by the building, while more heat is also produced by the braking resistor). The location makes low voltage (around 12 volt) distribution practical.

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Horizontal axis

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Horizontal-axis wind turbines(HAWT) have the main rotor shaft and electrical generator at the top of a tower, and must be pointed into the wind. Small turbines are pointed by a simple wind vane, while large turbines generally use a wind sensor coupled with a servo motor. Most have a gearbox, which turns the slow rotation of the blades into a quicker rotation that is more suitable to drive a generator.

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Vertical axis

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(or VAWTs) have the main rotor shaft running vertically. Key advantages of this arrangement are that the generator and/or gearbox can be placed at the bottom, near the ground, so the tower doesn't need to support it, and that the turbine doesn't need to be pointed into the wind. Drawbacks are usually pulsating torque that can be produced during each revolution and drag created when the blade rotates into the wind. It is also difficult to mount vertical-axis turbines on towers, meaning they must operate in the often slower, more turbulent air flow near the ground, resulting in lower energyVertical-axis wind turbines extraction efficiency.

wind power Wind power uses wind turbines which have their own generator built in. A wind turbine looks like a windmill with three blades. When the wind blows, the windmill rotates and the turbine generates electricity

Windmills in the Philippines

Advantages  Wind is free, meaning that wind farms need no fuel.  It produce no waste or greenhouse gases, making them great for the environment.  Wind is also a renewable resource; therefore it won’t run out like coal or other fossil fuels.  Wind farms can also be tourist attractions, generating more revenue that way, and helping the wind farm out.  Wind power is also quite useful for supplying power to remote areas, meaning it can go where other power sources cannot.  Wind farms are also quite useful in the fact that the land under the wind towers can still be used for farming.

disadvantages • They include the unpredictable behavior of wind. • The unsightliness of the wind towers. • Birds are sometimes killed in the blades. • Wind power can also effect television reception. • It can be somewhat noisy for an entire wind farm.

Disadvantages

horizontal axis and vertical axis

Description of operation

How it Works Wind power uses the same concepts as most other energy sources, using some force to turn a turbine. The turbine will then transfer its energy into a generator where electricity will be produced. The force to turn the turbine in wind energy comes from wind. Wind is created due to the unequal heating of air on earth from the sun, which produces different forces of wind dependent on the different air temperatures in each location. Traditionally, wind power could only be harnessed in high speed wind locations, where wind is annually over 13mph, but due to new technology and increased efficiency in generators, even lower speed winds can produce cost efficient wind power. These newer technologies include smart windmills where the pitch of the blade can be varied with the strength of the wind to achieve better efficiency.

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Inside the Wind Turbine

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Anemometer: Measures the wind speed and transmits wind speed data to the controller. Blades: Most turbines have either two or three blades. Wind blowing over the blades causes the blades to "lift" and rotate. Brake: A disc brake, which can be applied mechanically, electrically, or hydraulically to stop the rotor in emergencies. Controller: The controller starts up the machine at wind speeds of about 8 to 16 miles per hour (mph) and shuts off the machine at about 55 mph. Turbines do not operate at wind speeds above about 55 mph because they might be damaged by the high winds. Gear box: Gears connect the low-speed shaft to the high-speed shaft and increase the rotational speeds from about 30 to 60 rotations per minute (rpm) to about 1000 to 1800 rpm, the rotational speed required by most generators to produce electricity. The gear box is a costly (and heavy) part of the wind turbine and engineers are exploring "direct-drive" generators that operate at lower rotational speeds and don't need gear boxes. Generator: Usually an off-the-shelf induction generator that produces 60-cycle AC electricity. High-speed shaft: Drives the generator. Low-speed shaft: The rotor turns the low-speed shaft at about 30 to 60 rotations per minute. Nacelle: The nacelle sits atop the tower and contains the gear box, low- and high-speed shafts, generator, controller, and brake. Some nacelles are large enough for a helicopter to land on. Pitch: Blades are turned, or pitched, out of the wind to control the rotor speed and keep the rotor from turning in winds that are too high or too low to produce electricity. Rotor: The blades and the hub together are called the rotor. Tower: Towers are made from tubular steel (shown here), concrete, or steel lattice. Because wind speed increases with height, taller towers enable turbines to capture more energy and generate more electricity. Wind direction: This is an "upwind" turbine, so-called because it operates facing into the wind. Other turbines are designed to run "downwind," facing away from the wind. Wind vane: Measures wind direction and communicates with the yaw drive to orient the turbine properly with respect to the wind. Yaw drive: Upwind turbines face into the wind; the yaw drive is used to keep the rotor facing into the wind as the wind direction changes. Downwind turbines don't require a yaw drive, the wind blows the rotor downwind. Yaw motor: Powers the yaw drive

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types of windmills •One design of a modern windmill has two curved blades that spin on a vertical axis • strong cables act as “guy ropes” to anchor the mill and keep it upright.

The most efficient modern wind machines have 2 or 3 blades like the propeller of an aircraft. An electricity generator is located inside the head of the machine.The head also rotates to keep the blades pointed into the wind.

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Materials

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Raw Materials

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Windmills can be made with a variety of materials. Post mills are made almost entirely of wood. A lightweight wood, like balsa wood, is used for the fan blades and a stronger, heavier wood is used for the rest of the structure. The wood is coated with paint or a resin to protect it from the outside environment. The smock and tower mills, built by the Dutch and British prior to the twentieth century, use many of the same materials used for the construction of houses including wood, bricks and stones.

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The main body of the fan-type mills is made with galvanized steel. This process of treating steel makes it weather resistant and strong. The blades of the fan are made with a lightweight, galvanized steel or aluminum.

horizontal axis . familiar multi bladed windmills, used primarily for pumping water . modern two and three bladed lift devices similar to huge airplane propellers

vertical axis . darrieus rotor ( “ egg beater”) .the S- shaped savonius rotor

Horizont al -ax is • Most wind machines being used today are the horizontal-axis type. • Horizontal-axis wind machines have blades like airplane propellers . • A typical horizontal wind machine stands as tall as a 20-story building and has three blades that span 200 feet across. • The largest wind machines in the world have blades longer than a football field! Wind machines stand tall and wide to capture more wind

Vertical-axis

• Vertical–axis wind machines have blades that go from top to bottom and the most common type (Darrieus wind turbine) looks like a giant two-bladed egg beaters. • The type of vertical wind machine typically stands 100 feet tall and 50 feet wide. • Vertical-axis wind machines make up only a very small percent of the wind machines used today. • The Wind Amplified Rotor Platform (WARP) is a different kind of wind system that is designed to be more efficient and use less land than wind machines in use today. The WARP does not use large blades; instead, it looks like a stack of wheel rims. Each module has a pair of small, high capacity turbines mounted to both of its concave wind amplifier module channel surfaces. The concave surfaces channel wind toward the turbines, amplifying wind speeds by 50 percent or more. Eneco, the company that designed WARP, plans to market the technology to power offshore oil platforms and wireless telecommunications systems.

How many blades? Many Other Factors exist such as start-up speed, average wind speed, maximum wind speed etc.

•High Torque •Low Velocity •High Solidity •Water Pumping

•High Velocity •Low Torque •Low Solidity •Electricity

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How Wind Turbines Work Wind is a form of solar energy. Winds are caused by the uneven heating of the atmosphere by the sun, the irregularities of the earth's surface, and rotation of the earth. Wind flow patterns are modified by the earth's terrain, bodies of water, and vegetation. Humans use this wind flow, or motion energy, for many purposes: sailing, flying a kite, and even generating electricity.

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The terms wind energy or wind power describe the process by which the wind is used to generate mechanical power or 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.

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So how do wind turbines make electricity? Simply stated, 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. Take a look inside a wind turbine to see the various parts. View the wind turbine animation to see how a wind turbine works.

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This aerial view of a wind power plant shows how a group of wind turbines can make electricity for the utility grid. The electricity is sent through transmission and distribution lines to homes, businesses, schools, and so on.

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Windmills in the Philippines

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Power-generating windmills in Bangui Bay, Ilocos Norte, northern Philippines. Photo: AFP

Windmills in the Philippines •

Located at Bangui Bay, in the Ilocos Norte province of the northern Philippines, this wind farm is the first source of clean energy to be introduced to the many-islanded nation of 84 million folks, thus far reliant upon oil and gas for their needs.

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The project is the work of a private company, Northwind Power Development Corp, which is run by a Danish fellow and who received the bulk of its funding through no-interest loans provided by the Danish government.

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15 turbines, standing on 23 story high masts, starting pumping out juice back in May and now provide 24.75 megawatts of power, 40% of the supply in the Ilocos Norte province. The boost in electricity supply has provided power to many in the region for the first time.

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Costing more than 48 million dollars, which translates into about 2 million dollars per megawatt, is more than double the start-up cost of a normal power plant running on conventional fossil fuel and would not have been viable without the interest-free loans from the Danish International Development Agency.

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Since the project has been completed, Niels Jacobsen, the president and CEO of the company has had government and stateowned power company officials from across the country requesting help to try and replicate these windmills throughout the country.

design • •

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There are two classes of windmill, horizontal axis and vertical axis. The vertical axis design was popular during the early development of the windmill. However, its inefficiency of operation led to the development of the numerous horizontal axis designs. Of the horizontal axes versions, there are a variety of these including the post mill, smock mill, tower mill, and the fan mill. The earliest design is the post mill. It is named for the large, upright post to which the body of the mill is balanced. This design gives flexibility to the mill operator because the windmill can be turned to catch the most wind depending on the direction it is blowing. To keep the post stable a support structure is built around it. Typically, this structure is elevated off the ground with brick or stone to prevent rotting. The post mill has four blades mounted on a central post. The horizontal shaft of the blades is connected to a large break wheel. The break wheel interacts with a gear system, called the wallower, which rotates a central, vertical shaft. This motion can then be used to power water pumping or grain grinding activities. The smock mill is similar to the post mill but has included some significant improvements. The name is derived from the fact that the body looks vaguely like a dress or smock as they were called. One advantage is the fact that only the top of the mill is moveable. This allows the main body structure to be more permanent while the rest could be adjusted to collect wind no matter what direction it is blowing. Since it does not move, the main body can be made larger and taller. This means that more equipment can be housed in the mill, and that taller sails can be used to collect even more wind. Most smock mills are eight sided although this can vary from six to 12. Tower mills are further improvements on smock mills. They have a rotating cap and permanent body, but this body is made of brick or stone. This fact makes it possible for the towers to be rounded. A round structure allows for even larger and taller towers. Additionally, brick and stone make the tower windmills the most weather resistant design. While the previous windmill designs are for larger structures that could service entire towns, the fan-type windmill is made specifically for individuals. It is much smaller and used primarily for pumping water. It consists of a fixed tower (mast), a wheel and tail assembly (fan), a head assembly, and a pump. The masts can be 10-15 ft (3-15 m) high. The number of blades can range from four to 20 and have a diameter between 6 and 16 ft (1.8-4.9 m).

How does it works • http://www1.eere.energy.gov/windandhydro/printable_ versions/wind_animation.html

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