Vertical Axis Wind Turbine (VAWT)

Introduction

A vertical-axis wind turbine also known as VAWT is a type of wind turbine wherein the main rotor shaft is connected to the vertical wind blade (not necessarily to be vertically). The opposite side of motor that is the generator and gearbox is located near the ground. this is because if there is any mechanical or electrical problem, it should be easily accessible for the workers. There is no need for vertical-axis wind turbine (VAWT) to be pointed into the wind, which eliminates the requirement for wind-detecting and direction components.

Why vertical axis wind turbine?

  1. Higher efficiency
  2. Less space
  3. Cost is less as compared to HAWT

It is found that the vertical-axis wind turbine is more efficient than horizonal axis wind turbine. A VAWT has efficiency range of 10-15%. The efficiency can be increased by adjusting angle, rotation direction, turbine spacing, number of rotors, etc.

Material

The blade model of VAWT is based on NACA 0018 airfoil.

Wind turbines are made of fiber glass, steel, resin or plastic, aluminum iron or cast iron and  copper. Out of these material that are listed 3 material are most commonly used. Light wood like balsa wood is used as blade material. E-glass fiber is most widely utilized in wind turbine rotor blades mainly due to its low cost. Carbon fibers are also used in many aerospace and aerodynamic body applications. It is more expensive because they give higher modulus and strength than all types glass fibers.

Advantages:

VAWTs gives a lot of advantages as compared to HAWTs:

  1. VAWTs is Omni-directional and may not need to track the wind.
  2. Gearbox and motor replacement and maintenance are easier and more efficient, because the gearbox is accessible at ground level instead of working many of feet in the air.
  3. VAWTs may operate in conditions which are unsatisfactory for HAWTs.

Disadvantages:

  1. VAWTs regularly experience the ill effects of dynamic slow down of the edges as the angle of attack varies rapidly.
  2. The blades of a VAWT are fatigue and prone due to the wide variation in applied forces during every rotation.
  3. The vertically oriented blades can twist and bend during each turn, shortening their usable lifetimes.

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