App. - Wind Energy

Wind Energy

Wind Energy
 

One of the most promising renewable energy resources is the use of wind to produce electricity by driving enormous wind turbines (windmills).

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Eolic power is an inexhaustible, clean, nonpolluting source of energy with more advantages than disadvantages.
 

The most important disadvantages are our inability to predict precisely the force and direction of winds and the possibly negative impact that groups of large towers could have on the local landscape.

The History of Wind

Since ancient times, people have harnessed the winds energy. Over 5,000 years ago, the ancient Egyptians used wind to sail ships on the Nile River. Later, people built windmills to grind wheat and other grains.

The earliest known windmills were in Persia (Iran). These early windmills looked like large paddle wheels. Centuries later, the people of Holland improved the basic design of the windmill. They gave it propeller-type blades, still made with sails. Holland is famous for its windmills.

American colonists used windmills to grind wheat and corn, to pump water, and to cut wood at sawmills. As late as the 1920s, Americans used small windmills to generate electricity in rural areas without electric service. When power lines began to transport electricity to rural areas in the 1930s, local windmills were used less and less, though they can still be seen on some Western ranches.

The oil shortness of the 1970s changed the energy picture for the country and the world. It created an interest in alternative energy sources, paving the way for the re-entry of the windmill to generate electricity .
 

Wind Turbines

These modern, large wind turbines, between 150 and 200 feet (45 and 60 m) high, tend to be grouped in windy, isolated, mostly deserted regions. The most modern wind turbines can generate 500 to 2,000 kW of power.

The wind turbines are grouped into wind farms to maximize the potential of transmitting energy from only one location. This has the advantage of lowering costs and reducing environmental impact on the landscape.

The Turbine converts the wind into electrical energy through the use of simple technology based on mechanical gears.

Turbine Components :
 

Horizontal turbine components include:
• blade or rotor, which converts the energy in the wind to rotational shaft energy;
• a drive train, usually including a gearbox and a generator;
• a tower that supports the rotor and drive train; and
• other equipment, including controls, electrical cables, ground support equipment, and interconnection equipment
 

The blades: are movable. They can be oriented both to take maximum advantage of the wind and to slow down the turbine when the winds are too strong. When facing the wind, their shape causes a pressure difference between the two faces of the wind turbine's blades. The pressure on the blades produces a force that turns the rotor
 

Brakes: are activated when the winds surpass 74 miles per hour (120 km/h), preventing damage to the wind turbine.

Low-speed axle: turns slowly, between 20 to 35 revolutions per minute (rpm).

Multiplier(gearbox): With gears, it multiplies by 50 the speed of rotation of the high-speed axle.

High-speed axle: turns at around 1,500 rpm, allowing it to operate the generator.

Generator:  produces electric energy from the mechanical energy of the axle.

Cooling system: cools the generator with a fan. Also uses oil to cool the multiplier lubricant .

Computer (controller): controls the conditions of the wind turbine and its orientation.

The Journey of Electricity

1-The wind that moves the blades of the wind turbine, producing mechanical energy, which is then converted into electrical energy .

2- Energy
The electric energy produced by the generator goes down the cables to a converter.

3- Grid
After leaving the wind farm, the electric energy can be incorporated into the main distribution grid.

4-Homes
The electricity reaches the residential distribution grid and finally homes.

Disadvantages :

1-Predictability
One of the main disadvantages of wind power is that wind is very unpredictable. Strength can vary from none to storm force. Therefore, wind turbines are unable to produce the same amount of electricity at the same time. Sometimes, there will be no electricity generated. Another drawback of wind power is the associated cost.

2-Cost
another one of the disadvantages of wind power is the cost. Ideal locations for wind farms are usually very expensive to buy. Wind farms are also very expensive to maintain properly. In addition to the cost, another area of concern is the noise made by wind farms.

3-Noise
The level of noise made by turbines is also one of the disadvantages of wind power. One wind generator makes a low, swooshing sound 24 hours a day. Wind farms with many of these generators will make a lot of noise. Another problem with production is the amount of energy produced.

4-Production
Wind farms generally have a low energy output. While running at full speed, the largest turbine can only generate enough electricity to power 475 homes. Areas with a large population will need huge wind farms to generate power for a significant percentage of the population. Although wind power doesn't cause pollution while generating power, it does have a few negative impacts on the environment.

5-Environment
One of the final disadvantages of wind power is the effect on the environment. Birds like strong winds. It is very common for migrating birds to fly into wind turbines and get killed. Wind farms can also disturb your television reception if you live in the surrounding area.

 

74,000megawatts is the installed capacity of wind farms in the world. The leading country is Germany, followed by Spain and the United States.
 

Note: According to a recent article from Greentech Media, a Massachusetts aerospace company called FloDesign is working on a wind turbine concept that could potentially be at least twice as efficient as traditional rotor blade turbines, which force air around them instead of through them. It works by channeling wind into a vortex that spins the blades and generates electricity.

Benefits of FloDesign Turbines :

The traditional prop acts as an obstruction to airflow, forcing air around it instead of through it. To compensate for this, props are built at huge sizes, with blades around 150 feet long. Their size makes them fragile, requiring low rotational speed, and large gearboxes. FloDesign’s wind turbine extracts 3-4 times as much energy from the wind, allowing much smaller and faster blades. Diffusers provide greater efficiency at the expense of weight and length, and they are prone to separation of flow and losses. FloDesign’s mixer duct is less effected by off-axis flow, or turbulence, and uses FloDesign’s mixer ejector uses axial vorticity.

It’s like an Archimedes screw for air. When the two flows meet from different angles, they create a rapid mixing vortex. FloDesign’s turbine can automatically align to the wind direction like a kite string, and does not need motorized alignment. Traditional blades are enormous, and require special infrastructure to manufacture and transport. The FloDesign turbine can be disassembled to fit in one truck. FloDesign’s smaller robust rotor spins effectively at lower winds, but can also sustain higher winds in which other turbines would stall or break.

Traditional turbines require wide spacing, while FloDesign’s turbines can be placed closer together, optimizing land. While traditional turbines use fragile cantilevered beams, FloDesign’s shorter, stronger rotor benefits from a hoop. Traditional turbines require placement away from people and buildings. FloDesign turbines are inherently safer, adopting methods from the engineering of jet engines.

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