Horizontal Axis Wind Turbines
Horizontal axis wind turbines have been the standard for years
as opposed to vertical
axis wind turbines, which are now gaining favor with homeowners.
Horizontal axis wind turbines, as the name implies turn on a horizontal
axis or axel.
Some people still call these windmills and some still have blades
of old and are in a farm setting. But, the windmills of yesterday
are not the same as the horizontal axis wind turbines of today.
For example, most large utility scale wind turbines such as the
ones you'll find on wind farms use
a horizontal axis. Utility scale horizontal axis wind turbines typically
use three blades although some are now being developed that use
Railed against by some environmentalists as "bird Cuisinarts"
the utility scale horizontal axis wind turbines today are being
designed to move at slower speeds and be more visible to our fine
feathered friends. But, large utility scale horizontal wind turbines
are not the only games in town.
Residential wind turbines
that use a horizontal axis are also coming of age. These small wind
turbines will typically turn at lower wind speeds and may be mounted
in the backyard or on the rooftop.
Like many residential wind turbines for home use, the owners of
a horizontal turbine may have to fill out zoning paperwork and /
or get permission from one's homeowner association to place the
device on one's roof or in one's yard (It's recommended to get this
information upfront before buying or building your own).
The horizontal axis wind turbines (HAWT) need to be pointed into
the wind for optimal efficiency. The utility scale turbines may
do this by using a sensor and servo motor, while the smaller turbines
simply use a wind vane (tail-fan) to keep pointed in the right direction.