Wind Turbine Design
Efficient 3 blade upwind
The most efficient wind turbine design is of a tower holding a 3-blade rotor and an up wind (facing the oncoming wind) although some wind turbine designs only require two blades or are down wind.
Aeronautical Blade Design
Fixed Pitch Stall Regulated Blades (FPSRB)* ensure that the generator will operate even in strong gusty wind conditions.
*The Coemi 55kW G3 has additional centrifugal tip brakes (CTB) which automatically regulate the blade speed up to 25m/s wind speed.
Because the blades are fixed with no moving parts, they are more robust and lighter than variable pitch turbines with the additional benefit of a lower start up generating wind speed from 3 m/s (6.9mph)
The FSRB blades have been specially designed to cope with the strong gusting winds that are often experienced in the UK, especially near the coast. Because there are no moving parts they are far more robust than mechanical pitching systems.
UK Design - European Manufacture
Through partnership with a major Europeam manufacturer, the Coemi 55/15 50Kw is constructed from tried and tested Components supplied by European companies and constructed to IEC 61400-2:2006
ABB M2QA Generator
Wind turbines are designed to harness wind energy but are limited by the laws of physics to capturing just under 60 per cent of the wind’s kinetic energy. This is called the Betz limit. However, modern wind turbine technology means some machines can now capture 70 to 80 per cent.
Coemi-G3 turbines are the most efficient designs with a power conversion of 85% because they use a asynchronous generator which is directly connected to the grid with no need for an inverter.
Most commercial machines are based on the horizontal axis wind turbine (HAWT), but even the best wind turbine design needs to be right for its location. Different locations have different conditions, which in turn, require different equipment. Wind turbines require good steady winds to operated at maximum efficiency, level sites with little obstruction to the prevailing winds are ideal.
Positions close to high buildings, trees or on a ridge or brow of a hill should be avoided as these will cause turbulence, and irregular gusts.
The PLC (Programmable Logic Controller) monitors wind speed, wind direction, generator temperature voltage, amps and braking. As the wind increases the torque on the blades, electrical load (amps) is increased on the generator, maintaining the fixed rotation speed, similar to large wind farm generators.
There a clear advantages with these systems over old fashioned mechanically furled generators.
- Less maintenance
- Longer blade life
- Higher generation for a comparable size
- Larger capacity designs without compromising reliability and maintenance
Essentially, every element of the build must follow a tailored plan, taking into account many factors such as where the wind turbine is going to be placed and the infrastructure of the grid at your location. The size or possible up grade of your transformer is an important factor to be considered.