Vertical Axis Wind Turbines
Renewable energy options have many people around the world talking as they desire to reduce their costs of energy while also doing their part to protect the world. Rising sea levels and escalating pollution levels has generated worldwide interest and has given rise to new wind turbines designs. Many people are using turbines to help them take these steps.
Wind turbines mainly are of two types: vertical axis(VAWT) and horizontal axis(HAWT). HAWT are the most common type of wind turbines built across the world. VAWT is a type of wind turbine which have two or three blades and in which the main rotor shaft runs vertically. They are however used less frequently as they are not as effective as HAWT.
The Vertical Axis Wind Turbine (VAWT) is the most popular of the turbines that people are adding to make their home a source of renewable energy. While it is not as commonly used as the Horizontal Axis Wind Turbine, they are great for placement at residential locations and more. Here we will take a look at the VAWT, and fill you in on the pros and the cons as well as other important information that will alleviate stress and headache when you simply want to do your part to keep the environment protected.
Vertical turbines spin on the vertical axis and comes in various shapes sizes and colors. It’s movement is similar to a coin spinning on the edge. The main difference between the VAWT and HAWT is the position of blades. In HAWT, blades are on the top, spinning in the air while in VAWT, generator is mounted at the base of the tower and blades are wrapped around the shaft.
What is a Vertical Axis Turbine?
Vertical Axis Wind Turbines are designed to be economical and practical, as well as quiet and efficient. They are great for use in residential areas whereas the HAWT is best for use at a business location. There are two different styles of vertical wind turbines out there. One is the Savonius rotor, and the second is the Darrieus model. The first model looks like a 55 gallon drum that is been cut in half with the halves placed onto a rotating shaft. The second model is smaller and looks much like an egg beater. Most of the wind turbines being used today are the Savonius models. We will take a look more in- depth at both of these types of turbines available.
A wind turbine secures air into a hub, which them turns into a generator. The air that passes through the blades of the wind turbine is spun into the generator through rotational momentum. The VAWT, as the turbines are oftener shortened, feature the following qualities:
- Two to three blades with a vertically operating main rotor shaft – the more blades that you have on the unit, the more wind energy it will receive and the more efficiency it will offer
- Used less frequently than a horizontal wind turbine
- The position of the blades is different in the VAWT. On this model, the base of the tower holds the generator, and the blades then wrap themselves around the shaft. People use the VAWT because they can be placed closer to the ground, which makes them acceptable and effective for use at a residential location.
- With the vertical axis wind turbine, the rotor shaft is arranged in a vertical pattern
- The VAWT are easier and more affordable to maintain than horizontal units
- One complain that some users have with the VAWT is that is creates less wind energy, which may cause a number of different noises to be heart. Turbulent air flow is also a possibility that can shorten the life of the system.
- Installation of the VAWT onto the roof will cause the wind speed to double for maximum wind turbulence and wind energy usage.
Types of Vertical Axis Wind Turbines
As discussed above, there are two different types of VAWTs that you can choose from. While we looked at these types briefly above, now we will take a look at more information about each type and discuss the important factors that you should know. First, let’s take a look at the Darrieus wind turbine mode.
Darrieus Wind Turbine
Darrieus Wind Turbine is commonly known as an “Eggbeater” turbine. It was invented by Georges Darrieus in 1931. A Darrieus is a high speed, low torque machine suitable for generating alternating current (AC) electricity. Darrieus generally require manual push therefore some external power source to start turning as the starting torque is very low. Darrieus has two vertically oriented blades revolving around a vertical shaft.
The Darrieus wind turbine offers the following features:
- These eggbeater shaped turbines are great at efficiency, however, they are not as reliable.
- In order to use the Darrieus wind turbine you must have an outside source of power in order to start them
- It is in your best interest to choose a wind turbine that has at least three blades.
- To support such a wind turbine it is necessary that you have a superstructure which will connect it near the top bearing.
Savonius Wind Turbine
A Savonius vertical-axis wind turbine is a slow rotating, high torque machine with two or more scoops and are used in high-reliability low-efficiency power turbines. Most wind turbines use lift generated by airfoil-shaped blades to drive a rotor, the Savonius uses drag and therefore cannot rotate faster than the approaching wind speed.
Now let’s take a look at the second type, which is also the most popular of the two. The Savonius wind turbine is the most popular of the two types. Let’s go ahead and look at some of the features these VAWT offer to the homeowner.
- As a drag type of turbine, these units are less efficient.
- When you live in an area that has strong and gusting winds or when you need a unit that self-starts, this is the best type available to you.
- This unit is larger than the Darrieus model.
Savonius vertical axis wind turbine needs to be manually started. The slow speed of Savonius increases cost and produces less efficiency.
Which unit is best for you? There is no right or wrong answer. It is in your best interest to talk to a professional concerning the two types of turbines to determine which is best for you to use.
Advantages of Vertical Axis Wind Turbines
You might be wondering why you would consider using a VAWT instead of a HAWT. There are actually a number of reasons that this decision is made. Let’s take a look at some of the advantages that you can enjoy with this type of wind turbine in use at your home.
- You can build your wind turbine close to the ground so if you do not have a suitable rooftop for placement, or if you live where there are hills, ridges, etc. that prohibit the flow of air, they work wonderfully for your needs.
- Since VAWT are mounted closer to the ground they make maintenance easier, reduce the construction costs, are more bird friendly and does not destroy the wildlife.
- You do not need any mechanisms in order to operate the wind turbine
- Lower wind startup speed
- The main advantage of VAWT is it does not need to be pointed towards the wind to be effective. In other words, they can be used on the sites with high variable wind direction.
- You can use the wind turbine where tall structures are not allowed.
- VAWT’s are quiet, efficient, economical and perfect for residential energy production, especially in urban environments.
- They are cost effective when compare to the HAWTs. It is still best to shop around and check prices before making a purchase, however.
- Many of the turbines are resistant to many of the different weather elements that you may experience. It is imperative to choose a unit that offers this valuable protection and extra durability when you need it the most.
Disadvantages of Vertical Axis Wind Turbines
There are also disadvantages that come with the use of this type of wind turbine. While the many advantages are certainly great, it is imperative that you are aware of the disadvantages. Before deciding which type of wind turbine is best for you it is good idea to take a look at both the pros and the cons. What is right for one person may not be right for you, although it is safe to say that a VAWT is great for almost any residential setting.
Let’s take a look at some of the disadvantages of using a VAWT:
- Decreased level of efficiency when compared to the HAWT. The reason for the reduced amount of efficiency is usually due to the drag that occurs within the blades as they rotate.
- You are unable to take advantage of the wind speeds that occur at higher levels.
- VAWT’s are very difficult to erect on towers, which means they are installed on base, such as ground or building.
As you can see, there are far more advantages that come your way with the use of a vertical axis wind turbine, but still some disadvantages to be weary of.
VAWT’s in general produces less energy as compare to HAWT mainly due to the additional drag that VAWT have – as they rotate into the wind. Both VAWT and HAWT might differ in their appearance and mode of operation, but they generate electricity by converting the wind energy into electrical energy by using a rotating shaft. This is vital information for those looking to install HAWT in their home. Whether they are looking for turbines that will be ideal for when they’re sleeping, playing games or entertaining guests, HAWT is the better choice. In other words, wind turns the blades of the wind turbine around the turbines rotor. That rotor is connected to main shaft which in turn is connected to electric generator, which generates the electricity.
If you are looking for a great source of renewable energy that you can use at your residence, it is worth considering a vertical axis wind turbine. These turbines are designed to be used at homes, and while there are both pros and cons, for the most part those who use them appreciate and enjoy the energy that is produced. Before investing into either type of wind turbine, however, it is best to speak to a professional and discuss the pros and the cons of that decision. You’ll be glad that you went into the process as an informed consumer. The wind turbine is one of the most effective sources of renewable energy that you can find and you are sure to appreciate all of the wonderful benefits that it is sure to offer to you.
Image credit: Natesh Ramasamy ,
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