A wind turbine that spins in a spherical formation increases efficiency and reduces noise, according to its Dutch developer, Home Energy.
The Energy Ball (pictured below) replaces the traditional rotors of a wind turbine with an egg whisk-shaped structure designed to funnel wind within the turbine’s blades.
Erik Aurik, Home Energy marketing manager, said the technology works on the Venturi effect, which is usually associated with the drop in pressure that results when a gas or fluid flows through a constricted space at speed.
The spherical ball uses that principle by constricting the wind, so causing the pressure inside the ball to drop. The low pressure means the air flowing around the ball is sucked in and this helps turn the rotor blades.
The rotor blades use more wind and the turbine has a higher aerodynamic efficiency compared with conventional wind-turbine designs of the same diameter, said Aurik.
Most modern wind turbines are designed with three flat blades and the turbine’s head moves in the direction of the wind, using a computer-controlled system.
The tips of the blades, which can reach up to six times the speed of the wind, make perpendicular slices through the air, causing a swishing sound that some people find annoying.
The Energy Ball rotors are bent around in a ball shape so they primarily move parallel to the wind, making it quieter than conventional wind turbines, said Aurik. ’The noise of the Energy Ball will never exceed the wind sounds.’
It can also operate at very low wind speeds. ’The turbines will start turning at 2m/s and the Energy Ball can start generating electricity at 3m/s,’ he said.
The turbine is being marketed for small-scale energy use for homes, communities, businesses and public facilities.
For these types of applications, Aurik said the turbine can be installed easily on a pole 10-12m tall or a flat roof in four hours.
Optimum results can be achieved if the turbines are installed 40ft above the ground in an area free from trees and buildings.
The Energy Ball, sold in 1m or 2m diameter sizes, costs £2,000 to £4,000.
The company estimates that in places where there are winds faster than 15mph, a 1m turbine could generate up to 500k/Wh a year, while a 2m ball can supply 1,750 k/Wh a year.
According to a 2004 report by the Building Research Establishment, the average UK household uses 3,300kWh of electricity a year, which means the turbine could be a viable source of domestic energy.
Aurik added that the company is considering increasing the scale of the Energy Balls. ’Generally, in wind technology, twice the diameter will give a four times performance,’ he said.
Alternatively, Aurik said the turbines could be clustered to provide even more power. ’Wind parks with many of these balls can be foreseen,’ he claimed.
Siobhan Wagner
Why not a vertical axis?
No need for the ‘paint roller arm’ to align with the wind and less moving parts so greater reliability.
Not sure how you would control the RPMs. No auto-luff system.
Great idea though – reminds me of the ‘revo-jet’ rotary wing kite of my youth, recently re-invented for full size use. Memory says that wing buzzed louder than higher the wind so not sure about the whisper quiet claim either.
With a vertical axis, the weight of the ball would be supported by only one bearing, instead of being shared equally between two. In addition, a vertical axis would create a moment arm of flexure that does not exist with the paint roller design. On their website, a sound test by an approved laboratory documents the quiet operation. Now if tonly he maker produced a 120V 60cycle model for the U.S.!
I would rotate this idea 90* and put the alternator on the bottom.
In northern Australia almost every house and shed has several vents on top of the roof to remove hot air from the ceiling space. They are ball shaped with a vertical axis and about thirty blades. There are several manufacturers and they come in aluminium, or any colour steel. The wind powers them from an extremely low wind speed and the suction generated draws the air from below the roof and discharges it through the blades on the downwind side. There are many other variations of this design generating electricity or other energy forms.
R. Honnor,
Why not control RPM with an altenator stacked onto the generator? Once a strong wind overpowers the generator, excite the field coils of the alternator to provide braking, thus reaping the energy instead of wasting it. A simple circuit would make it self regulating as long as an electrical load is readily present. Say electrosis?
I’m not sure it can be oriented vertically. I wasn’t sure what the article meant about the “blades working paralell to the wind. Perhaps the need for the “paint roller design” is to align the axis of the machine to the wind.
Why else would the design complication be there? Don’t assume incompetence.
Paul
Follow the link, folks!
The wind is parallel to the axis of rotation.
So, it is not a paint roller but a pinwheel (with all due respect to the designers!)
I am excited with this turbine. can I place this turbine in water flow?