Horizontal Axis Wind Turbine and its Types

Wind turbines are machines that use the kinetic energy of the wind to generate rotational mechanical energy in their shafts. Wind turbines are mainly of two types Horizontal Axis Wind Turbine and Vertical Axis Wind Turbine.

In this article, we’ll look at the horizontal axis wind turbine types, which are by far the most prevalent.

Before we discuss the types, let’s have a brief look at horizontal axis wind turbines.

What is a Horizontal Axis Wind Turbine? 

Horizontal axis refers to the wind turbine’s rotational axis being horizontal or parallel to the ground. The majority of today’s horizontal axis turbines contain two or three blades, while several have fewer or maybe more blades. Most of the world’s wind energy is generated by huge three-blade horizontal axis wind turbines. Horizontal axis wind turbines come in a variety of sizes, ranging from 100 W to 100 KW.

The various components of a horizontal axis wind turbine (HAWT) are:

  • Nacelle
  • Rotors and blades
  • Gearbox
  • Tower
  • Yaw Mechanism
  • Wind controlling unit

Types of Horizontal Axis Wind Turbine:

There Horizontal Axis Wind Turbine is divided into 2 parts:

  • Upwind turbine
  • Downwind turbine
Source: www.slideshare.net

Upwind Turbine:

  • Upwind turbines have the rotor facing the wind.
  • This design is used in the majority of HAWT nowadays.
  • This turbine should be rigid and situated some distance away from the tower.
  • The primary benefit of this wind turbine is that it can prevent wind shading behind the tower.
  • It needs a yaw mechanism for the rotor to face the airflow constantly.

Downwind Turbine: 

  • Downwind turbines are those with the rotor on the tower’s bottom part. The wind is directed first toward the tower and then toward the rotor blades in various types of wind turbines.
  • This turbine does not have a yaw mechanism. The rotors and nacelles are developed in a way wind can flow through the nacelle in a regulated manner.
  • It experiences some variation in wind power since the rotor travels through the wind shadow of the tower. In a nutshell, the rotor is located after the nacelle of the tower, causing wind power fluctuations.

Upwind Turbine vs. Downwind Turbine:

  • The rotor of an upwind turbine is mounted in front of the turbine, receiving the approaching airflow. On the other hand, downwind turbines have their rotors on the rear side, allowing the nacelle to confront the wind immediately. 
  • In upwind turbines, a yaw mechanism is required to keep the rotor constantly facing the wind. In contrast, downwind turbines may not need the yaw mechanism. 
  • The design of upwind turbines makes them more expensive in comparison with downwind turbines.
  • Upwind rotors have the benefit of not being affected by the tower shade phenomenon. Whereas in downwind turbines, since the rotors are on the downside of the tower, the blades might experience unequal pressure as they travel through the tower’s shade.

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