Types of Wind Turbines
On the basis of axis of rotation of the blades, it is divided into two parts.
1. Horizontal axis wind turbine (HAWT)
2. Vertical axis wind turbine (VAWT)
Horizontal Axis Wind Turbine (HAWT)
It is a turbine in which the axis of rotation ofrotor is parallel to the ground and also parallel to wind direction.
Horizontal axis wind turbines (HAWT) are the predominant turbine design in use today. The HAWT rotor comprises blades (usually three) symmetrically mounted to a hub. The rotor is connected via a shaft to a gearbox, and the generator is housed within the nacelle. The nacelle is mounted atop a tower connected to a concrete foundation.
HAWT come in a variety of sizes, ranging from 2.5 meters in diameter and 1 kW for residential applications up to 100+ meters in diameter and over 3.5 MW for offshore applications.
The theoretical maximum efficiency of a HAWT is ~59%, also known as the Betz Limit. MostHAWT extract about 50% of the energy from the wind that passes through the rotor area. The capacity factor of a wind turbine is its average power output divided by its maximum power capability. On land, capacity factors range from 0.26 to 0.52. Offshore winds are generally stronger than on land, and capacity factors are higher on average, but offshore wind farms are more expensive to build and maintain. Offshore turbines are currently placed in depths up to 40-50m (about 131-164ft).
They are further divided into two types
(i) Upwind turbine
(ii) Downwind turbine