A wind lense power generation system has been developed at Kyushu University by the Ohya Group of the Research Institute for Applied Mechanics that dramatically increases the output of wind turbines - and makes them quieter.
A shroud structure creates vortices behind it to draw more mass flow into the wind turbine. The researchers say this produces a two to five times increase in output power compared to conventional wind turbines.
Additionally, the Wind Lens system results in a significant reduction in wind turbine noise due to suppression of tip vortices; and may also reduce interference in Doppler radars.
Rotating wind turbine blades can effect radar beams by reflecting back energy generated by a radar. This returned energy can be seen as an area of rain, throwing out algorithms used to estimate rainfall and to detect storms.
This effect also has implications for civil aviation and defence, as radar operators can find it difficult to differentiate between aircraft and wind turbines; a scenario that has led to wind farms being banned in some areas.
The University says it’s these issues the technology addresess that make the Wind Lens system suitable for installation in a variety of sites, including heavily populated areas.
Kyushu University currently has a number of Wind Lens power generation system turbines installed around its campus - 2 x 70kW units in the northwest and 10 x 5kW turbines installed at the Multipurpose Sports Field and other areas. According to the University, these installations have a combined estimated annual electricity output of approximately 120,000 kilowatt hours.
The first stage of off-shore wind farm development utilising the lense technology has also begun. Construction of a floating 18 meter diameter structure hosting a pair of 5kW Wind-Lens turbines is expected to commence soon in Hakata Bay. Another offshore wind farm consisting of a larger floating structure 60m in diameter with two 100kW Wind-Lens turbines will be constructed at a site in the Genkai-nada Sea, Fukuoka.
