Vertogen Ltd
Variable pitch vs Fixed Pitch VAWT Vertogen 2019 02 12 V01 Video
Why is a Variable pitch blade VAWT better than Fixed pitch?
This video is for those wanting to understand, the simple benefits
of Vertogens variable pitch blade system.
Versus
a fixed pitch blade.
------------------------------------------------------------
Many wind turbines use a shaped blade, or aerofoil. Similar to an aircraft wing in flight.
Where air flow meeting the wing shaped blades at a near optimum angle is the key to the efficiency and power of any turbine.
This creates the lift…
This same lift keeping the aeroplane up, creates the drive on the blades and rotation of the wind turbine.
Too steep an angle causes the air to separate from the wing and cause turbulence and a drag or braking force.
In aircraft this would result in reduced lift or very little, and it faliing out of the sky. Or wind turbines being inefficient or stopping.
So having a variable pitch of the wing shaped blades improves efficiency over a fixed blade system AND Starting in a light breeze or low wind speed as ALL blades are all adjusted toward the best possible angle for efficiency and power generation, as it rotates in the wind.
How can we see this difference ?
Using CFD (Computational Fluid Dynamics).
The science that engineers use to predict fluid or air flow over given objects. We can present a visual presentation of the simplified basic differences in efficiency, drag and turbulence.
The Fixed blade system, is less efficient as lift is created by only one or two blades meeting the wind flow at the better angle and slowed by a braking turbulence generated from the remaining blades meeting the air at a worse angle
The other blades also suffer from this mixed up air. The result is limited output from the available wind energy.
The variable pitch system shows lift from more than two blades and less drag from the other blades. Which translates into a higher level of wind energy absorption and output in the form of power or mechanical drive energy.
The general issues for vertical wind turbine technology applications are:
Starting in a light breeze low wind speed
The Variable pitch allows the Turbine to start in lower wind speeds and higher RPM can be obtained due to lower drag or stall effect of the blades.
(low wind speed being 1metre to 3 metres per second)
Efficiency (the ability of the unit to maximise the of amount the wind energy collected crossing the wind turbine)
Working in near gale force or higher wind speeds
(20 metres per second +)
Maintaining a controlled and smooth RPM speed at high wind speeds
With a Vertogen Variable pitch VAWT a smaller size Turbine could be used making a portable version.
Also the characteristics of the power curve should generate more torque at a lower RPM, which can make it more suitable for other applications, such as driving pumps and machinery. Torque is the amount of force measured like a car engine output.
One of the key aspects to wind turbines generally, is the perceived noise that is produces.
Variable pitch units tend to be quieter and deliver more power because of the fact that the leading edge of each blade is moving to “cut into the air” at a better angle of approach
Also the remaining blades have reduced wind drag effect because of their pitch and this combination provides for a less confused or turbulent air pattern within and around the turbine unit as a whole.
Performance difference between Fixed and Variable Pitch.
Variable pitch vertical (VAWT) types are very rare at the moment.
Many fail to consider that the variable system allows the vertogen turbine to work for much longer periods over a wider range of wind speeds
While the fixed blades systems are motionless in low wind speeds.
The current Industry tends to measure turbine output at given wind speeds and a short time period.
For variable pitch VAWT turbines. They would need to consider performance over a much longer period and in fluctuating wind conditions.
We suspect the overall performance increase seen will be dramatic.
Graph
The Variable pitch can produce more torque throughout the RPM range.
If you examine the basic graph which shows output from the two types, you will notice the Variable Pitch IN BLUE out performs the fixed system IN RED at every level which is further proof of increased performance.
www.vertogen.eu
Meadowcroft Farm Barn
Harwood Rd
BURY, BL8 3PX
United Kingdom
+44 7968 073 404
mike@vertogen.co.uk
david@vertogen.co.uk
https://www.linkedin.com/company/18321038/
Variable Pitch VAWT
Variable Pitch Vertical axis wind turbines
Why what is variable pitch required in VAWT
Cyclone wind turbine
More efficient Vertical axis wind turbines
Vertogen variable pitch
What is a vertical wind turbine
Theory of variable pitch
This video is for those wanting to understand, the simple benefits
of Vertogens variable pitch blade system.
Versus
a fixed pitch blade.
------------------------------------------------------------
Many wind turbines use a shaped blade, or aerofoil. Similar to an aircraft wing in flight.
Where air flow meeting the wing shaped blades at a near optimum angle is the key to the efficiency and power of any turbine.
This creates the lift…
This same lift keeping the aeroplane up, creates the drive on the blades and rotation of the wind turbine.
Too steep an angle causes the air to separate from the wing and cause turbulence and a drag or braking force.
In aircraft this would result in reduced lift or very little, and it faliing out of the sky. Or wind turbines being inefficient or stopping.
So having a variable pitch of the wing shaped blades improves efficiency over a fixed blade system AND Starting in a light breeze or low wind speed as ALL blades are all adjusted toward the best possible angle for efficiency and power generation, as it rotates in the wind.
How can we see this difference ?
Using CFD (Computational Fluid Dynamics).
The science that engineers use to predict fluid or air flow over given objects. We can present a visual presentation of the simplified basic differences in efficiency, drag and turbulence.
The Fixed blade system, is less efficient as lift is created by only one or two blades meeting the wind flow at the better angle and slowed by a braking turbulence generated from the remaining blades meeting the air at a worse angle
The other blades also suffer from this mixed up air. The result is limited output from the available wind energy.
The variable pitch system shows lift from more than two blades and less drag from the other blades. Which translates into a higher level of wind energy absorption and output in the form of power or mechanical drive energy.
The general issues for vertical wind turbine technology applications are:
Starting in a light breeze low wind speed
The Variable pitch allows the Turbine to start in lower wind speeds and higher RPM can be obtained due to lower drag or stall effect of the blades.
(low wind speed being 1metre to 3 metres per second)
Efficiency (the ability of the unit to maximise the of amount the wind energy collected crossing the wind turbine)
Working in near gale force or higher wind speeds
(20 metres per second +)
Maintaining a controlled and smooth RPM speed at high wind speeds
With a Vertogen Variable pitch VAWT a smaller size Turbine could be used making a portable version.
Also the characteristics of the power curve should generate more torque at a lower RPM, which can make it more suitable for other applications, such as driving pumps and machinery. Torque is the amount of force measured like a car engine output.
One of the key aspects to wind turbines generally, is the perceived noise that is produces.
Variable pitch units tend to be quieter and deliver more power because of the fact that the leading edge of each blade is moving to “cut into the air” at a better angle of approach
Also the remaining blades have reduced wind drag effect because of their pitch and this combination provides for a less confused or turbulent air pattern within and around the turbine unit as a whole.
Performance difference between Fixed and Variable Pitch.
Variable pitch vertical (VAWT) types are very rare at the moment.
Many fail to consider that the variable system allows the vertogen turbine to work for much longer periods over a wider range of wind speeds
While the fixed blades systems are motionless in low wind speeds.
The current Industry tends to measure turbine output at given wind speeds and a short time period.
For variable pitch VAWT turbines. They would need to consider performance over a much longer period and in fluctuating wind conditions.
We suspect the overall performance increase seen will be dramatic.
Graph
The Variable pitch can produce more torque throughout the RPM range.
If you examine the basic graph which shows output from the two types, you will notice the Variable Pitch IN BLUE out performs the fixed system IN RED at every level which is further proof of increased performance.
www.vertogen.eu
Meadowcroft Farm Barn
Harwood Rd
BURY, BL8 3PX
United Kingdom
+44 7968 073 404
mike@vertogen.co.uk
david@vertogen.co.uk
https://www.linkedin.com/company/18321038/
Variable Pitch VAWT
Variable Pitch Vertical axis wind turbines
Why what is variable pitch required in VAWT
Cyclone wind turbine
More efficient Vertical axis wind turbines
Vertogen variable pitch
What is a vertical wind turbine
Theory of variable pitch
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