It seems wind energy means thinking big, both when it comes to the size of the wind turbines themselves, and in the size of the wind parks. The trend seems to be for ever larger installations, for which the costs of access routes and electrical connections as well as technical infrastructure can be offset against the greater number of wind turbines. So does the future of wind energy lay with giant offshore set-ups and wind farms on mountain ridges, hill tops and great plains that can only be financed by energy conglomerates or major investor groups?

Here the company Aircon GmbH & Co.KG offers an alternative. The development of the first prototype small-scale wind turbine began over 10 years ago. The company was founded in 2003 to further develop and commercialize the early prototypes. The company now markets, in the form of the Aircon 10, a “small-is-beautiful” wind turbine that is just as suitable for rural businesses as for manufacturers or for institutions that are striving to become independent of constantly rising energy costs by generating their own energy.

The Aircon 10 has a rotor diameter of 7.6 metres. It is produced in two models: the S (stall-controlled) and SP (Stall-controlled turbine with rotor-blade feathering), each with a rated power of 10 kilowatts, which is achieved at a nominal wind speed of 11.0 metres per second (24.6 mph or 21.4 knots). Special masts with a height of 12 to 30 metres are made for the rotors.

The centre piece of the Aircon wind turbines is the patented gearbox- free SPARK generator: the acronym SPARK stands (in German at least) for synchronous machine with permanently excited axial field and ring core winding. The generator was a new development in collaboration with the IMAB Brunswick, with a view to efficient electricity generation, but also to specific design requirements and simple production of the installations. The machine has an outstanding power and energy density per unit volume and mass compared with other generators. The main reason for this is that the power generation takes place not, as in conventional machines, on a circumferential surface between rotor and stator, but on radial surfaces. Mathematically speaking, with the circumferential surface the power increases with the square of the diameter, but in the SPARK the increase is approximately cubic.

A power electronic regulator with variable turning speed controls the feeding of the generator current into the grid. It reacts in a variable way to different wind conditions, and makes the power from the wind turbine into a calculable quantity. The absence of the detent torques found with a conventional generator, the gearbox-free construction and optimised disc-magnet design lead to favourable rotor starting behaviour and low noise generation. The rotor blades are also optimised for noise and performance.

The power of the generator can be increased at will by combining stator/disc-magnet modules. All this leads to a high level of electrical efficiency combined with economically efficient production costs. And the principle also works with water power. Aircon also offers the Spark generator for operation with a hydroelectric turbine.

Aircon’s small wind turbines offer an individual solution to the problems of high electricity costs and CO2 emission reduction. The current from the turbine can be fed directly into the domestic grid, thus supplying house and home; any excess can be sold to the public grid (Feed in Tariff pending in Ireland) or used for heating. This makes electricity costs a known quantity in the long term, and when the unit has paid for itself, you even get free electricity.

Aircon GmbH & Co. KG and dealers worldwide are looking optimistically towards the future. Their distribution network in Europe already includes Sweden, Italy, Ireland, France, Spain, Austria, Switzerland, the Netherlands, Belgium, Germany, USA and Canada. In these countries numerous Aircon 10 wind rotors are turning; in Denmark they supply Roskilde University’s power grid, in the Netherlands a wind park was built with ten Aircon 10s, and in Cape Cod Massachusetts a high school is supplied from an Aircon 10. In the United Arab Emirates, an Aircon 10 wind turbine has provided the most spectacular proof to date of the durability and reliability of wind turbines. The unit was erected on the top of a levee bank reaching a long way into the sea. In June 2007, Cyclone Gonu raged there, destroying the levee bank and all the structures erected on it – except the Aircon 10. The wind turbine remained standing; admittedly perched lopsidedly on the remains of the wind-destroyed levee, but itself undamaged, testament to its superior durability in the market place. For those who are interested in wind power on a small scale, the outlook is fine whatever the weather, thanks to Aircon.