I am looking for feedback on an idea that I have developed for a new concept vertical axis wind turbine. If there is anyone from an engineering/design (nuts and bolts), architectural or computer aided design background out there then I would especially like to hear from you.
My ideas are set out in a pdf document that can be downloaded here:
http://commons.wikimedia.org/w/index.ph … amp;page=1
http://www.keepandshare.com/doc/2292492 … -749k?da=y
The document does include a link to my Hub Pages profile so I might be breeaking forum rules by posting these links here. If this is the case then I apologise.
I think my ideas are worth serious consideration and that - if they are developed: from text and diagrams, into a fully functioning system - they could make a worthwhile contribution to a sustainable future.
Be the Change.
Wow thats pretty cool! Ive seen a few different types of vertical axis wind turbines before. How does this one work?
Sorry about the delay in replying here - I haven't received any notification that people were responding to this thread.
You might get more of an idea about how my system works by reading my reply to Chris57 below.
Thank you both for your interest.
Do you have any figures?
How much energy is harvested from the air?
What airspeed is required?
I am a professional engineer. I majored in fluid dynamics.
Even if i add up all my Bernoulli and Continuity equations and spice with some partial differentials, i am sorry, i don´t get a clue of how this thing works.
How do you want to force air through your device? Air does not accelerate by itself. You have to invest energy first. This is nothing new. For windturbines the energy balance is positive. You get more energy out than you invest.
This trading of energy is what leads to a certain efficiency ratio in wind harvesting, not to mention the theoretical Betz-ratio of 60%.
Have you run test?
I am sorry, but am very sceptical.
It operates by exploiting a pressure gradient - a pressure gradient is generated when a moving mass of air encounters an obstacle - with positive pressure building up in front (up-wind) of the obstacle - and negative (relatively) pressure (down-wind) behind.
This is the same pressure that architects know as 'wind-loading'. Architects have to design buildings that are strong enough to withstand the lateral/horizontal pressure exerted by the moving air mass that the buildings obstruct. The amount of force exerted in this manner can be considerable.
If you provide a passage (or shortcut) through a building - that connects the areas of positive and negative pressure - the resultant airstream will both move faster and exert more kinetic energy than the wind (moving air mass) from which it has been derived.
With due respect - pressure differentials themselves do not produce power output.
Energy can only be drawn out of wind or moving air by decelerating the air. The more you decelerate, the less energy is contained in the wind. If you do this to speed 0, then no air will come out of a tunnel and consequently no wind will go into the tunnel. If you try to take energy out of air, you have to allow the air to flow, to move.
Actually that is what Betz law expresses.
When you force air through a tunnel (like in your example) you better not put anything into the tunnel to extract energy. The wind will decide to go around the tunnel and not through it.
And also consider that local increase of kinetic energy is necessarily always drawing that energy differential from thermal energy. It is just a change of gas conditions, total energy doesn´t change. It cools the gas down. That is what happened in old fashioned carburators, they could freeze because of thermal energy being used up by accelerated air.
I am afraid no air will flow through your device. And if air goes through, no mechanical energy can be extracted. And make sure the thing doesn´t freeze over.
A question - how do ducted 'windmill type' wind turbines work? They obviously do. This is proven technology.
Moreover, the wind is - indeed - the result of thermal energy input from our Sun. Quite how you are trying to relate this fact to my system is, however, puzzling to say the least.
I will be setting out my ideas in a hub at some point. This will give me the opportunity to explain my concept at length and in greater detail. This - in turn - should make the operating principles of my system more readily understandable to someone who might, otherwise, struggle to understand them.
I hope you will consider posting comments to that hub when I get around to publishing it.
Many thanks for your input CHRIS57.
Peter, i did a little investigation on diffusor assisted wind turbines. Found this publication from Technical University of Delft, Netherlands.
http://repository.tudelft.nl/view/ir/uu … 38e1be888/
I would use the term: diffusor assisted, not diffusor augmented, because there is no real increase in power output per air flow volume. Compared to free running turbines the ratio of efficiency is significantly lower and i suspect that it would be even lower than it already is if not some energy was taken out of thermal energy in the air flow. So still beware of freezing in the diffusor ( as mentioned in my previous comment).
Just one comment about the paper i put the link on.
The paper would not get my approval. There is no reference of any kind to the real issue behind, which is energy harvesting. There is no energy balance investigated.
I earn my living searching for new technologies and methods. I put technical ideas to reality and last but not least it is my job to keep my company from entering technological dead ends. I am on one hand a pathfinder and on the other a bouncer, blocking doors to dead ends.
Please , Peter, keep your ideas for yourself. There is little chance you are successful, firstly for the laws of physics and secondly for economic reasons. And - illustre names like Grumman aerospace appearing in white papers don´t help either.
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