Companies behind a new vertical-axis wind turbine believe it could revolutionise the global landscape of onshore wind farms dominated by horizontal-axis designs.
The micro-generating turbine was designed by leading structural, aeronautical and electrical engineers in the UK with small businesses, farms and local communities in mind.
The concept was built around tackling fatigue, an ongoing issue in HAWTs with wind coming from all directions, creating bearing and gearbox stress due to pitch requirements.
The VAWT is features low-drag airfoils and a low rotor speed of 32 rpm, which means there is no need for a blade pitch control system.
Having power, electronics, motor and gearbox at ground level makes it easy to maintain, while wear is reduced and performance should be improved beyond the 20-year predicted lifespan.
UK company 4Navitas Green Energy Solutions worked with Siemens and HMK for a year and half to refine the engineering of the wind turbine. Drive, motor, coupling and gearbox use an integrated drive system, with output currently rated at up to 75kW and a 1MW version in the pipeline.
The turbine has a helical bevel gear unit at its base and the IE3 rated motor is close coupled with the gearbox. The shaft is supported by bearings down the mast so gearbox load and fatigue transfer is reduced.
The VAWT has a near silent-running, said the makers, by earthing through the tower, two buttress legs and grillages that reduce resonance and noise to just 40dB – the equivalent of a quiet library.
Noise has been an ongoing issue with onshore wind turbines and the reduction in noise means the turbine could be located in populated areas, near schools, hospitals and even within communities.
In micro-generation terms, the turbine is 37 metres tall, less than its HAWT counterparts, taking up a much smaller footprint with no need for a large concrete base, engineers said.
The 4N-55 VAWTs are now moving into serial production, after undergoing extensive testing, including to almost three times normal operating speeds (100 rpm at the mill).
The company is also considering international licences for its worldwide manufacture.
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