Nacelle Design

From Wind wiki

The nacelle is a closed part of almost all wind turbines. This is where all the parts of the mechanical drive train and of the electric generator can be found. Some smaller turbines do not have closed nacelles, as it will be redundant if there is a closed housing in turbines with completely integrated drive train components.

Nacelle design is associated with how the drive train components are arranged, particularly the rotor bearing assembly. Commonly, wind turbines have nacelles featuring a supporting bedplate with a non-loaded fairing. In earlier made turbines, a welded steel structure is commonly used as a bedplate. The bedplate is the part which moves all the rotor forces to the tower through the azimuth bearing found in the front. This comprises most of the weight of the turbine considering the stiffness needed for the parts of the drive train. In modern turbines, cast nacelle bedplates are found especially in series production. Cast bedplates are often heavy and flanged to a light-weight sheet steel structure that accommodates the generator.

Material

There are different materials used for the bearing fairing structure in wind turbines. These days, laminated shells made of fiberglass are the most commonly used because of their insulation against noise and temperature property, which is a requisite in selecting material and design. Sound insulation is necessary to prevent gearbox noise while temperature and humidity insulation works to protect the components of the electronic control.

Size

The size of the nacelle, which plays a vital role in the total production cost of the wind turbine, should be considered. A compact nacelle design with short pathways for the transfer of force from the rotor to the tower makes the tower head light-weight and less costly. Large turbines produced recently are often identified by their smaller nacelles which are purposely structured to provide more space for the installation of the nacelle parts, as well as accessibility for any maintenance work.

Shape

How a wind turbine looks is determined by the shape of its nacelle. Basically, shaping is not necessary since the wind does not have to flow around the nacelle. In the past, only a little value was placed for nacelle design; perfecting the function of wind turbines was given more emphasis. It was only recently when wind turbines became widely used that manufacturers considered the shape of nacelles to make their products more saleable. Generally, designers have the freedom to choose a style for nacelles as long as the shaping adheres to aerodynamic principles.