Wind power has been used by people around the world for many years. From the antique windmill of yesterday, built of wood and used to pump water or mill grain, to the sleek, modern wind generators of today, wind power has always proved a stable and clean source of energy production. While technology has enhanced the performance and reliability of wind machines, the main design principles remain the same.
A wind generator needs several components in order to function properly. While the first windmills were simple in design, utilizing only the rotary system and a tower, wind generators of today contain an electrical generator, which may or may not have a gearbox, as well as a rotary and structural support system.
In the past several decades many scientists and inventors have labored to improve on the size, shape and mechanical design of the windmill, in an effort to make wind generators an even more efficient means of producing electrical power. While the basic components remain the same for all wind generator designs, the shape and engineering of the towers and rotors vary from one design to the next.
Horizontal Axis Wind Turbine Designs
By far the most commonly used design, wind turbines with a horizontal axis rotary system can be found on private residences, farms, small business sites and even wind farms across the west and mid-west. Retaining much of the same shape and many of the design features of a traditional windmill, modern horizontal axis wind turbines have a rotary system and power generator which is located near the top of the support structure (tower.)
Up-dated versions may have only three rotary blades, which are made of solid, rather than flexible material. One drawback associated with this horizontal axis wind turbine design is that the machine must be positioned so that it is directly into the wind.
Horizontal axis wind mills may feature either constant rotation speed or variable rotation speed. The use of a gear box is necessary to create a variable rotation speed, for a horizontal axis wind turbine.
Vertical Axis Wind Turbine Designs
Wind machines which are designed as vertical axis turbines are being used much more often today, than in previous years. One of the greatest benefits of the vertical axis design is that this type of rotary system often demonstrates better performance in the presence of variable wind conditions, The vertical placement of the rotor shaft also allows for more diverse options in set-up, for example the generator and gear boxes can both be placed nearer to the ground. Additionally, vertical axis wind turbine do not need to placed directly facing the wind. Vertical axis wind mills designs are often utilized for roof-top systems.
There are several lesser known versions of the vertical axis wind turbine design. These include the parallel wind turbine, Darrieus (or eggbeater) wind turbine, the giromill and the Savoius and the twisted Savoius