ENBREEZE 15 KW WIND TURBINE
THE WIND TURBINE IN DETAIL - A PITCH-REGULATED DOWNWIND WIND TURBINE
The enbreeze 15 kW wind turbine is a pitch-regulated downwind wind turbine with active wind direction tracking and three rotor blades which rotate around the horizontal axis. The wind turbine has a rotor diameter of 11.5 meters and a rated power of 15 kW. The hub height of the wind turbine is about 20 meters, and the highest point of the wind turbine including the rotor blades is 26.6 m. The lower segment of the steel tower of the wind turbine has a diameter of 813 mm, and the upper segment has a diameter of 508 mm. This keeps the shadow casting of the wind turbine to a minimum. With a 15 kW small wind turbine, enbreeze is serving a whole new market segment. We want to show small and medium enterprises, municipalities, and research and teaching institutions a way to implement their contribution to sustainability efficiently and economically. To achieve this goal, we have chosen a wind turbine size that is unique in this market segment.
The enbreeze 15 kW wind turbine is much smaller than standard large wind turbines (150 m), but, with about 20 m hub height, is significantly larger than very small wind turbines for private use. Since the enbreeze 15 kW achieves optimum yields even at low wind speeds, it is very quiet and fits into the cityscape well, is a real alternative for the generation of decentralized power in urban areas, and is a useful complementary technology to photovoltaics. Another advantage is the compactness of the wind turbine. It is crucial for the planned use in developing markets, especially in areas without connections to the grid. All components can be transported preassembled in a container and shipped inexpensively. On site, setting up the wind turbine in remote areas is easy to implement, including erection of stand-alone systems.
ALL THE FACTS AT A GLANCE - EFFICIENCY IN FUNCTIONAL MODERN DESIGN
|Rated power||15 kW|
|Rated wind Speed||8.3 m/s|
|Switch-on speed||2.5 m/s|
|Rotor diameter||11.5 m|
|Area swept||103.9 m²|
|Number of rotor blades||3|
|Rated Speed||83 1/min|
|Rotor blade material||GRP/CFRP|
|Inner workings / control system material||Steel/aluminum|
|Generator||Permanently excited synchronous generator, direct drive|
|Grid connection||By frequency inverter|
|Output voltage||400 V (3 ph.)|
|Power limitation||enbreeze passive pitch control|
|Wind direction tracking||Active, downwind|
|Main brake||enbreeze passive pitch control, fail-safe|
|Tower||Steel tower, foldable|
|Hub height of tower 1||about 20 m|
|Weight of nacelle incl. rotor||1200 kg|
|Tower weight||4560 kg|
|Total weight||5760 kg|
|Sound level||Max. 40 dB at 60 m distance|
|Rotor blades||52% (peak efficiency)|
High energy yield even with low average wind speeds. Meet electricity demand through high capacity utilization of up to 35% per year (PV 10%). Easy integration into any house connection (3 phase / 400 V) or DC power connection for electric mobility. Tiltable tower for fast setup and easy service, hydraulically driven.
PURELY MECHANICAL CONTROL SYSTEM & LOW-MAINTENANCE WIND TURBINE
The 15 kW wind turbine is distinguished by the innovative pitch system that enables pure mechanical control of the wind turbine. The control system developed by enbreeze operates on a purely mechanical basis. It requires no control by sensors. Using attacking wind and generator loads, as well as centrifugal forces, the angle of attack of the rotor blades is successively adapted to the prevailing wind conditions. In case of a fault, the rotor blades can be individually moved out of the wind, thus representing a redundant safety system.
Low maintenance – enbreeze 15 kW does not require expensive electronic components and allows precise control of the rotor blades to optimize performance.
EVERYTHING UNDER CONTROL - HIGHLY EFFICIENT ROTOR BLADE WITH IDEAL AERODYNAMICS
In cooperation with aero_designworks and our CFD specialists, a rotor blade was developed whose profiling and profile control are adapted to the low and highly variable wind speeds at ground level. The rotor blades were aerodynamically optimized in regard to their design. Through this design of the rotor blades, an optimum degree of efficiency is made possible even in turbulent wind. Since the rotor blades rotate out of the wind or optimally into the wind without failure-prone electronics, a significant reduction in physical stress is achieved at the same time as a constant yield. The rotor blades are continuously moved in or out of the wind by the control system depending on the wind conditions. They are made of a carbon fiber-reinforced structure (CFRP) with a glass fiber-reinforced plastic (GRP) shell.
THIS RESULTS IN IMPORTANT ADVANTAGES:- Aerodynamic degree of efficiency of over 50% - High energy absorption even in gusty winds - Low noise emissions - The rotor blades are manufactured by the the Rostock company Baltico with a CFRP structure structure in a consistently lightweight design.
Aeroelastic simulations are used primarily in the development of wind turbines. It takes a huge computational effort for the simulation of wind turbines by conventional methods (CFD), especially since a rotating wind turbine must be modeled for a wide range of wind situations. For every rotational speed, for every wind speed, for every pitch angle, for every azimuth position, the loads on the wind turbine need to be simulated. Tens of thousands of necessary simulations quickly come together.
This cannot be modeled with conventional CFD simulations. Only with aeroelastic simulations can the simulations be performed quickly and accurately. Finite-element methods are dispensed with and work is carried out with simplified physical descriptions that have been refined through many years of research and adaptation models. It is now possible to perform a simulation within a few seconds and with high precision on commercially available computers. Large wind turbines in particular are now constructed using aeroelastic simulations. However, the use of input and output parameters requires a lot of experience and expertise. The results must be interpreted correctly in the context of each case.
The programs for the simulations are usually the result of many years of work in research institutes. Well-known programs are Bladed, Fast, and HAWC2. In the small wind area, aeroelastic simulation is rarely used, but it is the norm for small wind turbines, DIN EN 61400-2, already prepared for this case. With a full aeroelastic simulation, the safety factors for the design can be significantly reduced.
enbreeze GmbH benefits in particular from the consideration of the control system of aeroelastic simulations. By including them, the operating loads can be reduced considerably and a more cost-effective and slender wind turbine design can be implemented. Moreover, the simulations provide highly accurate results regarding any stress situation and thus offer a high degree of safety in the design of the wind turbine.