Wind turbines with a vertical axis of rotation.

Scientists at the Sandia National Laboratories (USA) are developing wind turbines with a vertical axis of rotation for offshore power plants, promising to make them cheaper and more efficient than conventional ones.

Meanwhile, the developers of Ehmberg Solutions (Sweden) has already built a prototype of such a generator.

Existing wind turbines are divided into two main types — a vertical axis and the horizontal. The latter is dominated today: they have a higher efficiency, and calculate their design is much simpler, although it is more difficult — because of the orientation of the device in the wind. First not require such devices, and therefore have fewer moving parts and needs to be repaired. Key elements of such turbines are much closer to the ground, making them easier to service. To the knowledge of their potential in offshore wind farms and appealed researchers from Sandia Labs.

One of the main problems of wind turbine with a vertical axis of rotation — an impressive diameter. If a conventional horizontal wind turbine it should be about 90 meters to the surface to produce megawatts or more, the vertical of the same capacity required to have about 270 m even make such a monster — a problem.

However, the Americans say, this deficiency is largely an advantage. Common windmill has a certain angle of the blades and, depending on the wind speed are changed, or turbine efficiency drops. This limits the potential size of the horizontal wind turbine blades because of its sensitive to different direction and wind speed in the lower portion of its path, and the top: the angle of the vanes, optimum above will not be as below. Given that the current horizontal turbines can have a zone slew height of 100 m, larger in size, these will not do: the efficiency starts to fall.

Vertical wind turbine has no such limitation: its effectiveness is not dependent on the wind direction and speed. A setting angle of the blades does not need any adjustment he continually changes during rotation of the blades along the vertical axis.

For a conventional wind turbine will need a massive tower, the foundation on the seabed and a huge floating crane for installation and repair. But for a competitor with a vertical axis of rotation — no. (Illustration Randy Montoya.)

Another important advantage of the projected laboratory system is called its increased stability, which is crucial for an offshore wind farm. As it turned out, the rotation around the axis (supports) she stabilizes itself like a spinning top or whirligig. The stronger the wind, the stronger the stabilizing vertical turbine rotation. Therefore, even in a storm it almost threatens to capsize, and submerged part should not, in contrast to the horizontal wind turbine, support touch bottom. In other words, the vertical wind turbine buoyant, it was not dug into the seabed. Even the anchor rope he needed only to avoid drift and drift. Thus, the engineers say, they are working out the design of offshore power plants will not only be less cumbersome and less expensive than existing horizontal wind turbines, but also be able to move further out to sea. After all, it does not necessarily reside only at a very shallow depth: wind turbine can anchor and where conventional bearings require enormous length, and therefore will cost a pretty penny.

And here we should remember that offshore wind turbines with a vertical turbine worked not only in the United States. Swedish startup Ehmberg Solutions has experienced a small-sized (ten-meter) prototype of this design:

Science and technology

Science and Technology / Energy / Alternative Energy /
Wind turbine with a vertical axis of rotation may be the best solution for offshore power plants

July 31, 2012, 14:04 | Text: Alexander Berezin | Listen to this news

Scientists at the Sandia National Laboratories (USA) are developing wind turbines with a vertical axis of rotation for offshore power plants, promising to make them cheaper and more efficient than conventional ones.

Meanwhile, the developers of Ehmberg Solutions (Sweden) has already built a prototype of such a generator.

Existing wind turbines are divided into two main types — a vertical axis and the horizontal. The latter is dominated today: they have a higher efficiency, and calculate their design is much simpler, although it is more difficult — because of the orientation of the device in the wind. First not require such devices, and therefore have fewer moving parts and needs to be repaired. Key elements of such turbines are much closer to the ground, making them easier to service. To the knowledge of their potential in offshore wind farms and appealed researchers from Sandia Labs.

On the left — a wind turbine with a vertical axis of rotation, the right — the usual. (Photo Spiritrock4u.)
On the left — a wind turbine with a vertical axis of rotation, the right — the usual. (Photo Spiritrock4u.)

One of the main problems of wind turbine with a vertical axis of rotation — an impressive diameter. If a conventional horizontal wind turbine it should be about 90 meters to the surface to produce megawatts or more, the vertical of the same capacity required to have about 270 m even make such a monster — a problem.

However, the Americans say, this deficiency is largely an advantage. Common windmill has a certain angle of the blades and, depending on the wind speed are changed, or turbine efficiency drops. This limits the potential size of the horizontal wind turbine blades because of its sensitive to different direction and wind speed in the lower portion of its path, and the top: the angle of the vanes, optimum above will not be as below. Given that the current horizontal turbines can have a zone slew height of 100 m, larger in size, these will not do: the efficiency starts to fall.

Vertical wind turbine has no such limitation: its effectiveness is not dependent on the wind direction and speed. A setting angle of the blades does not need any adjustment he continually changes during rotation of the blades along the vertical axis.

For a conventional wind turbine will need a massive tower, the foundation on the seabed and a huge floating crane for installation and repair. But for a competitor with a vertical axis of rotation — no. (Illustration Randy Montoya.)
For a conventional wind turbine will need a massive tower, the foundation on the seabed and a huge floating crane for installation and repair. But for a competitor with a vertical axis of rotation — no. (Illustration Randy Montoya.)

Another important advantage of the projected laboratory system is called its increased stability, which is crucial for an offshore wind farm. As it turned out, the rotation around the axis (supports) she stabilizes itself like a spinning top or whirligig. The stronger the wind, the stronger the stabilizing vertical turbine rotation. Therefore, even in a storm it almost threatens to capsize, and submerged part should not, in contrast to the horizontal wind turbine, support touch bottom. In other words, the vertical wind turbine buoyant, it was not dug into the seabed. Even the anchor rope he needed only to avoid drift and drift. Thus, the engineers say, they are working out the design of offshore power plants will not only be less cumbersome and less expensive than existing horizontal wind turbines, but also be able to move further out to sea. After all, it does not necessarily reside only at a very shallow depth: wind turbine can anchor and where conventional bearings require enormous length, and therefore will cost a pretty penny.

And here we should remember that offshore wind turbines with a vertical turbine worked not only in the United States. Swedish startup Ehmberg Solutions has experienced a small-sized (ten-meter) prototype of this design:

As it turned out, the stabilizing effect of rotation allows him to work quietly in the wind up to 19 m / s. The highlight of the project is the energy storage system — just in case, if the wind suddenly happen lull. The fact that the entire lower part of the submarine is also rotated SeaTwirl (excluding the generator and the anchors). Naturally, she is like a spoon in a glass of tea, during acceleration up to a top speed of sea water spins around. With this calm sea water slows down very slowly, simultaneously preventing slow down the wind turbine, which continues to spin without the wind. At the same time, according to the calculations of Swedes, one full-size turbine (up to 210 m) with a capacity of 10 MW stores 25,000 kW • h — two and a half hours of their own peak output. Yes, some loss of efficiency in rotating the water turbine during acceleration can not be avoided, but they are small (1-2%) and significantly less than the cost for an alternate energy storage capacity on land.

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