A new kind of turbine design was on display at Yokohama’s Renewable Energy International Exhibition 2010. The Wind Lens, an idea developed by Professor Yuji Ohya at Kyushu University would have a 112-m dia. and focus the wind into the rotor by means of a hoop. Capturing higher speed wind would mean generating more power.
According to Ohya, his Wind Lens can double, even triple, the power output of a conventional wind turbine, as well as reduce the noise pollution and increase safety of the installation. Wind turbines have been accused of ruining landscapes and creating a lot of noise. In some cases, high wind speeds have torn down turbines and damaged surrounding agriculture. With a floating hexagon base, the Wind Lens might eliminate these risks.
Japan started to center its attention on wind power after tinkering with geothermal power from its volcanoes and hot springs for a number of years. Wind makes up 2% of the world’s energy, somewhere near 159.2 GW. Of course, every technology using natural resources has to adapt to various site conditions. This makes Ohya hesitant to predict wide success or adoption of the Wind Lens. “Despite its merits, even if this technology does enter the Japanese market, it may not be easily adopted by other countries.”
Still, it could be successful in windy countries like Denmark, Austria, Germany, and Norway, or states like Texas.
Filed Under: Turbines
Al Gold:
In spite of the fact that some of what you say happens, I think Yuji Ohya’s idea is not far fetched.
There is an advantage of building heavier turbines, the RPM is more stable as a result.
You would not have to resort to using expensive materials for the blades if the tips were fixed to a wind lens. If the tips are free, they have to break the air as it moves but the wind lens that is fixed to the tips does not; a free tip is what makes most of the noise.
It is relatively simple to turn the drive from horizontal to vertical without much energy loss and to maintain the turbine perpendicular to the wind direction.
Locating the gearbox and multiple generators at ground level has at least four advantages: reduced tower structure required to avoid damage by earthquakes; much reduced heavy hoisting to the top of the tower during construction; better design possibilities because of more space available and; much better access for maintenance.
The Incas knew all about earthquake design. Start big and heavy at the bottom and reduce the weight above and keep it symmetrical.
That is why some of their buildings are still standing, Pizzaro’s priests simply built their cathedrals on top of what the Incas had built.
Some of the Chileans forgot the lesson and most of the damage during the 8.8 Richter earthquake of February 2009 resulted from poor symmetry and weight distribution.
Lets keep an open mind and keep the comments coming.
Paul V. Preminger
Kathleen;
As I understand Yuji Ohya’s design, the wind direction is with the lip downwind.
It appears to me, after going through some of the literature by Yuji Ohya et al, that the hoop does not act like a funnel but instead generates vortices that create a negative pressure effect on the wind flow that has passed through the hoop.
Regards;
Paul V. Preminger Direct contact: paulpreminger@hotmail.com or paulpreminger@gmail.com
Paul, could you explain to me some of the concepts and graphs at http://www.tinyurl.com/windlens .
In the first graph it shows a X/L ratio of 0 when the wind velocity is at its highest. How can you get 0 ratio?
Is the brim at the back of the system?ie downwind. It would then be a venturi, not a cowling or funnel, wouldn’t it?
Ross:
Thanks for the comments. You’re right in that a ratio cannot reach 0. Remember calculus graphs: As a value for a variable approaches zero, the function would something physically impossible in the real world. So the value in the graph is getting close to 0, not equaling it.
Is the brim upwind or downwind? Good question. Look at http://www.windtamerturbines.com. They make a shrouded turbine and it looks like the brim is downwind.
Paul
Wouldn’t they be better off giving the blades have a larger cross section to the wind so there would be less blow past, and reducing the size of the system to make the tip speed faster?
I foresee a large amount of flex at the hub in the system as shown, which would stress the outer rim hugely and interfere with the gap between the magnets and the coils, assuming they are located on the outside of the fan.
What’s wrong with 100% coverage of the collection circle? You could then cross brace the blades for strength.
Ross:
You ask good questions. I think the professor’s ideas are concepts at this point having worked only with what appears to be 1 to 2 meter diameter prototypes.
Paul
I don’t think this will work. A 5MW system’s rotor is over 100-m diameter and wind changes direction several times a second, you try to make it pitch at right angles with the wind flow to avoid the stall. I don’t see it physically possible. Blades construction is already getting into carbon and fiberglass to cut weight, and this proposal uses 6 blades. What’s more, many concepts with cowlings work only on 2D CFD models. They fail in wind tunnel or field trials.
Mr. Gold:
Thanks for your comments.
The images just show an idea. I say let the professor build a prototype and prove the concept. I agree there was a lot of information missing such as where is the generator, how will it rotate, why so close to the surface, and more.
The 112-m diameter would not be impossible by supporting the blades at the circumference and center. One or two smaller and shrouded turbines have been announced. And if the turbines were sited at a location with winds in a near constant direction, as they might be between two islands, constant and large pitch changes would be unnecessary. The professor shows a little of his research here: http://www.tinyurl.com/windlens
You have to admit, Photoshop does a great job of making ideas look real.
Paul