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» New Rooftop Wind Turbine Technology

Publicado em: 30/10/2015
Stephen Hanley - Green Building Elements

Wind power is a major source of renewable electric power in many places around the world. We usually associate wind power with tall wind turbines located in remote locations or far out to sea. In July, Denmark produced 140% of its domestic energy from just such turbines, according to The Guardian. Yes, that record was established over a rather windy 24-hour period, but it is remarkable all the same.

Archimedes rooftop wind turbine

Until now, small wind turbines that are sized for residential and urban areas have produced a power output that is too low for a reasonable return on investment through energy savings for all but a few people. Also, they create more noise than most homeowners are comfortable with. But according to Off Grid Quest, a small rooftop wind turbine may change all that.

A Dutch renewable energy startup called The Archimedes is working to solve both of those problems. It is building a new small-scale wind turbine — one that is almost silent and is far more efficient at converting wind into energy. The company says its Liam F1 turbine can generate 1,500 kWh of energy per year at wind speeds as low as 11 miles per hour. That would be enough to cover half of an average household’s energy needs.

The shape of the blades pays tribute to Archimedes, the noted Greek scientist credited with leading the way toward the mathematical power of calculus. He also invented the screw pump and the compound pulley. The Liam F1’s blades are shaped like a Nautilus shell. The design allows it to point into the wind to capture the most amount of energy, while also producing very little sound. The inventor of the turbine, Marinus Mieremet, says that the power output is 80 percent of the theoretical maximum energy that could be harnessed from the wind.

“Generally speaking, there is a difference in pressure in front and behind of the rotor blades of a windmill. However, this is not the case with the Liam F1. The difference in pressure is created by the spatial figure in the spiral blade. This results in a much better performance. Even when the wind is blowing at an angle of 60 degrees into the rotor, it will start to spin. We do not require expensive software: because of its conical shape, the wind turbine yaws itself automatically into the optimal wind direction. Just like a wind vane. And because the wind turbine encounters minimal resistance, he is virtually silent,” said Mieremet.

When used in combination with solar panels, a house with an efficient rooftop windmill could operate almost entirely independent of the electric grid. “When there is wind you use the energy produced by the wind turbine; when the sun is shining you use the solar cells to produce the energy,” The Archimedes CEO Richard Ruijtenbeek said.


The wind often blows strongest at night, when solar panels typically have no effect. Making a wind turbine part of a home’s energy system might permit going off grid with a smaller storage battery than needed with solar panels alone. Smaller batteries cost less and that would make going completely off-grid a more affordable option for home owners.

Fonte: http://greenbuildingelements.com/2015/10/12/new-rooftop-wind-turbine-technology/