Page 28 - Energize Issue 1 2023

TECHNICAL

facing the wind produce a low-pressure potential which drives an
internal flow stream from a separate inlet, through an internal
radial turbine that extracts energy and then ejects the residual
air into the free stream. The unit begins operating at around 2,5
m/s (9 km/h). It cuts out at about 25 m/s (90 km/h). The units
are designed to withstand extreme wind speeds of up to 53 m/s
(190km/h). Aside from the small turbine in the base, there are no
spinning or moving parts.
Wind passes through an arrangement of opposing aerofoils,
Figure 13, which creates an area of low pressure between the two
blades.
The unit is rated at 5 kW maximum output and is claimed to
produce more electricity than an equivalent area of solar panels. Figure 11: Typical application of Aeromine WT (Aeromine)
Designed for use on flat-roofed buildings, the unit can take
advantage of the air speed-up phenomenon when placed on the
edge of the building’s roof. Air speed-up is a known phenomenon
of surface terrain, and is often taken advantage of by placing wind
turbines on ridges and at the top of hills, etc. Air speed-up applied
to buildings is illustrated in Figure 14. A wind front approaching
the building is compressed when passing over the building and
since the same volume of air has to pass through a smaller area,
the wind speed increases.
The efficiency of the unit is fairly low, rated at between a third
and a half of the theoretical maximum efficiency for wind turbines,
according to laboratory tests. The unit is directional and must face
5
into the wind to offer maximum efficiency. Output is maintained
within a window of 45° on either side of facing directly into the
wind but drops off rapidly outside of this window.
The unit has been tested extensively by Sandia National Figure 12: Aeromine principle (Aeromine)
Laboratories and several are on field trial. It is claimed that one
unit produces about the same amount of electrical energy as
16, 300 W solar panels. The cost, while not explicitly stated, is
reported by the company to be no greater than solar panels that
produce equivalent energy.

References
1. M Hadi Ali: “Experimental Comparison Study for Savonius Wind
Turbine of Two & Three Blades At Low Wind Speed”, IJMER Vol. 3,
Issue. 5, Sep - Oct. 2013
2. E Kulunk: “Aerodynamics of Wind Turbines”, www.intechopen.com
3. S Pol et al: “Performance of AeroMINEs for distributed wind
energy”, SAND2019-7063C Figure 13: Air flow between aerofoils (Sandia NL)
4. F Wenehenuben: “An experimental study on the performance of
Savonius wind turbines related with the number of blades.”, Energie
Procedia 68 (2015)
5. S Tongdee: “Study on performance of a Savonius wind turbines
related with the blade angle”, Maejo International Journal of
Energy and Environmental Communication, 2019
6. E Topas: “Vertical axis hybrid wind turbine design”, Journal of
mechatronics and AI in engineering, June 2020
7. F Mitjans: “Energy efficiency assessment of four designs of vertical
axis and drag differential wind turbines”, IOSR-JEEE, vol. 13, Issue 1
8. M Mahomed: “Performance enhancement of a Savonius turbine
under effect of frontal guiding plates”, Energy Reports 7 (2021)

Send your comments to rogerl@nowmedia.co.za Figure 14: Wind speed-up over buildings

energize | Issue 1 2023 | 28