This article deeply explains the vertical and horizontal axis wind turbine. Wind energy is a significant energy source through that we generate very cheap electricity by using its power. It is a process of using wind to produce electrical energy or mechanical energy. A wind turbine is a mechanical device that transforms the rotational energy of the turbine in the form of electrical power. Professor James Blyth invented the first wind turbine in the 1887s. This article is about different types of wind turbine. A wind turbine has two major types.
- Vertical axis wind turbine
- Horizontal axis wind turbine
In this article, I will explain these two major types of wind turbine. I will also explain the difference between a vertical axis wind turbine and a horizontal axis wind turbine. The details of these wind turbines are given below.
1) Vertical Axis Wind Turbine (VAWT)
Vertical axis wind turbine or VAWT includes in the most famous types of wind turbine. The principal shaft of the VAWT rotor fixes in the vertical direction of the wind. While some other major parts place at the turbine base. You don’t have to turn it into the wind direction for the turbine to work effectively. VAWT has this major advantage in the areas where the direction of the wind fluctuates significantly. The gearboxes and generators of these turbines can position closer to the ground by driving them directly from the assembly of the rotor to the base’s gearbox, increasing maintainability. The vertical axis wind turbine gearbox is much more fatigue as compared to other types of wind turbine (horizontal axis wind turbine) gearbox. However, this type of wind turbine has a major disadvantage: the average energy generated by these designs is low compared to horizontal axis wind turbine.
A vertical axis wind turbine is specially planned to be economical, practical, efficient, and quiet. These turbines work well for use in inhabited areas, while HAWT is best for commercial areas. VAWT has mainly two various types. Darrieus model is the first type, and the Savonius model is the other one. The Darrieus model is small and looks like a whisk. The Savonius rotor looks like a 55-gallon drum which cuts in half and place half on the revolving shaft. Nowadays, maximum wind turbines are using as Savonius models.
Advantages of VAWT (Vertical Axis Wind Turbine)
- The vertical axis wind turbine has easy maintenance than the horizontal axis wind turbine.
- Its maximum components situate near the ground. That is due to the shape of the VAWT.
- There is no need for a Yaw device.
- A vertical wind turbine has a large angle of airfoil pitch. This improves aerodynamic performance while reducing drag at high and low pressure.
- Alignment does not require as it is omnidirectional. Besides, a Vertical axis wind turbine does not require any yaw control.
- It works in gusty and turbulent winds.
- VAWT can be used in traffic areas, urban areas, rooftops, etc.
- A group of VAWTs can be placed together.
- It can install in horizontal axis wind turbine wind farms under the existing HAWT. This can increase the production of the present plant.
- The Derrius types’ blade has easy manufacturing than the blades of other types of wind turbine (HAWT blades).
Disadvantages of VAWT
- It needs to be mounted in comparatively flat terrain, and some locations may be too urgent for VAWT.
- The VAWT attached with a pull wire causes serious problems with the lower bearing as it supports the full weight of the rotor, and the pull wire increases the downward thrust due to the gust of wind. To solve this problem, you will need some structure to hold the top bearing in place. The upper bearings can also share the weight of the rotor.
- Complex geometric shapes, installation, and angle changes problems vary widely.
- A vertical axis wind turbine is less reliable.
- It has low efficiency.
- The average energy generated by a vertical axis wind turbine is low compared to other wind turbine types (horizontal axis wind turbine).
- Automatic start problems at the low speed of the wind.
- VAWT blades are prone to fatigue due to the very different forces exerted with each revolution.
- Vertical blades can bend and twist with every rotation. And this breaks the blades of the vertical axis wind turbine.
2) Horizontal Axis Wind Turbines (HAWTs)
HAWT or horizontal axis wind turbine also includes in the famous types of the wind turbine. The major shaft of the rotor of a HAWT fixes in the horizontal direction, and this makes it different from vertical axis wind turbine. The large 3-blade wind turbine with a horizontal axis (HAWT) generates most of the world’s wind energy today when the blades surround the tower. These turbine towers have a generator and a rotor shaft that must be directed into the wind. The horizontal axis wind turbine sizes vary from hundreds of watts to hundreds of kilowatts. These HAWTs are usually deployed in streamlined air conditions that allow constant airflow and direction to pick up maximum wind power.
HAWT is generally placed in a constant directed airflow as it does not affect turbulent areas.
Advantages of HAWTs
These advantages of HAWT are given below.
- As compared to a vertical axis wind turbine, it has high output power.
- In a horizontal wind turbine, the vanes lie on one side of the turbine center of gravity, which improves stability.
- Adjust the angle of attack remotely to improve control and allow the turbine to extract the extreme volume of wind power during the day and the season.
- It has the ability to distort the blades so that the blades of a turbine have the optimal attack angle.
- It is cheaper as compared to other types of wind turbine.
- A tall tower receives stronger winds when the wind shear changes.
- High efficiency.
- The blade can also tip the rotor blade during a storm to minimize damage.
- The horizontal axis wind turbine has too high reliability than other turbine types (vertical axis wind turbine).
- Higher rate of capacity.
- It is more reliable.
- Mostly self-starting.
- It has high rotational speed.
Disadvantages of HAWTs
- It has large in size.
- Its transportation is difficult.
- Difficult to install
- The maintenance of horizontal wind turbines is difficult than other types of wind turbine.
- Large machinery needs for the construction of HAWT.
Difference between Vertical and Horizontal Wind Turbine
|1.||It works in turbulent airflow conditions.||It works in streamflow air conditions.|
|2.||The major rotor shaft of vertical axis wind turbines fixes in a vertical direction.||The major shaft of the rotor of a horizontal axis wind turbine fixes in the horizontal direction.|
|3.||Low rate of capacity,||The high rate of capacity.|
|4.||It has low efficiency.||It has high efficiency.|
|5.||Maintenance is easy.||Maintenance is difficult.|
|6.||It is less reliable.||It is more reliable.|
|7.||Drag is a major force.||Lift is a major force.|
|8.||Yaw mechanism is not required.||Yaw mechanism required.|
Advantages of VAWT Over HAWT
Currently, commercial VAWT is less efficient than commercial HAWT. However, this will eventually be reversed as VAWT has the capability to be more efficient. Let’s say a VAWT that is two times as wide and high will increase its performance by 35% if the wind direction is inclined by 25o. If the VAWT efficiency is 45% when placed vertically, this slope will also rise to 61%. This is even higher than HAWT and also achievable by this turbine. When a horizontal axis wind turbine leans (bends) away from the wind, it just loses its power. With a vertical axis wind turbine, the power increases and decreases with increasing the tips’ bending. The wider the VAWT, the more efficient it is.
Specific VAWT configurations can generate inexpensive power than HAWT. VAWT offshore wind farm is one of them. Adjacent stacked rows of rotors are used, and the entire wall is protected from the wind (high heels) for the maintenance and control of the Overspeed. Using many stacked VAWTs, the wind wall advantages from the law of the square/cube scale. In simple words, cost and mass increase at about a similar rate as the swept area. For very large HAWTs, however, the potential costs and mass increase faster than the area swept.
The wind wall floats freely, adjust around the fixed buoy to handle the wind. Compared to other single VAWTs or HAWTs, the wind wall’s total area is much larger, and the components are small sufficient to get an advantage from mass production.
Wind Turbine Manufacturing Companies
- TUGE Energia (Estonia)
- Southwest (USA)
- Guietrevolution (UK)
- Hi-VAWT (Taiwan)
- Enessere (Italy)
- Borny (Spain)
- World Wind (India)
- China Guodian Corporation (China)
- Suzlon (India)
- RRB Energy Limited (India)
- Inox Wind (India)
- Elecon Engineering (India)
- PacWind (USA)
- Shanghai Electric (China)
- SANY (China)
- Goldwind (China)
- Evision Energy (China)
- CRRC (China)
- UNISON (South Korea)
- Senvion (Germany)
- NoyaWind (Russia)
- Nordex SE (Germany)
- Acciona (Spain)
- Enercon (Germany)
This article is about the types of the wind turbine. In this article, I explain different aspects of the horizontal axis and vertical axis wind turbines. So, VAWTs are easy to install, but their efficiency is low than HAWT. In this article, I try my best to explain these two turbines. If you have any problems related to this article, let me know in the comment section. I will try my best for your clarification.