'Wind Lens' Could Triple the Power Output of Turbines

Have they heard of Betz' Law?

You had to make me look it up didn't you?
Those pics in the article don't stand up to scrutiny.
I reckon all Betz are off <groan>
Del

Hello JohnDG,

if they manage to increase the power flow within that additional ring, it means they will have more kinetic energy per unit area and time. So they will get more mechanical power without "switching off" Betz' law.

This is not the first concentrating scheme proposed, and some look quite similar.

Regards

Snel

This is like the "mount a wind turbine on a trolley, connected via a drive train to the road wheels - once you get it moving, it'll go faster and faster and faster ..." argument discussion. It doesn't work.

The area of the turbine inlet appears (from the images) to be only about 10%-ish greater than the area swept by the blades. It cannot "suck air in", tho' it may increase the air flow (and hence power) a bit. I can see that a large funnel could do some good, but not these things. They may gain a little - but a 200% increase???

I stand to be corrected, but it seems to me like pie-in-the-sky. These claims need to be peer-reviewed, before any poor suckers get sucked in.

I have often wondered if some kind of earthen structure could help boost a turbines power by directing more air to the blades, and away from the area between turbines.

Was the article ghost-written by joe.fordham?

Additional income could be produced if they hang small carriages around the circumference and call it an "Eco ferris wheel".

Could triple power, could be cheaper, could ... etc.

As JohnDG pointed out, Betz's Law (yeah, I had to look it up, too) limits the efficiency of any wind turbine to just under 60%. It's a theoretical limit making extreme assumptions of massless props and so forth. The explanation I read appeared to assume a laminar air flow; I don't know if a turbulent flow, such as this 'lens' creates, would make any difference or not, though I didn't see anything in the math that would suggest any way to change the max value.

I suppose if a wind turbine was consistently operating at well below the Betz limit, say at 10%, over a wide range of wind speeds, then a 3x increase would be possible -- but would anyone actually design and build one that operates that poorly?

One other comment concerns the main drawing. To get maximum efficiency the propeller must face the wind, and the lens must remain in a fixed relationship to the prop. The large drawing shows fixed (floating) propellers on barges, with no obvious way for each propeller assembly to rotate into the wind. Makes me wonder who did the sketch and wonder if the Japanese researchers approved this sketch.

Turbulent flow makes a big difference - output drops off greatly.

I think these guys are just trying to get funding so they can have jobs.

Betzs law has proven out well over the many years since he wrote it. No one has been able to beat it yet.

Hmmmm, a ducted turbine and stator. More efficient? Very likely. As cost efficient? Not so likely.

Search 'ducted turbine' - more efficient is the one statement you won't find - along with 'operational'.

Sorry wrong syntax. shrouded propeller is what I should have said.

This is the application I learned about them.

While a 300% improvement would mean a 15 to 20% efficiency to start with, more realistic would be 20 to 50%. The issue is cost and complexity just went up 300% or more to get it.

If you spin the shroud mass becomes an issue, If the shroud is stationary then clearance and wind direction get complex. For a uniform wind in a non changing direction the shrouded propeller is hard to beat. Add variable dynamics and life gets interesting.

Suppose a turbine was 40% efficient. Then making it 3 times as efficient, it would be 120% efficient? I don't think so.

I can certainly see that such a lens could possibly improve the efficiency of a wind turbine. Not unlike the way winglets work on the wings of modern aircraft I feel.

I found the video on YouTube (it has been removed from the web link) and the first demonstration on the video, assuming that the air speed itself was not changed to falsify the results, was pretty impressive.

Where I am at a loss, is why is the lens fixed in position on the larger versions. If it was part of the turbine and turned with it, although bearings/impeller etc. would need to be beefed up of course, it should improve efficiency/stability due to not needing the fixed supporting arms.

Also, the extra weight should work as a flywheel, evening out the gusts etc. and the small effects of the spinning lens, "throwing" the air out at the back centrifugally, might actually further increase the efficiency a further small amount......

Furthermore, it should also help with the stability of some sort of "furling" system to allow the turbine to slow or furl the blades when storms or generator failures happen that could produce a dangerous situation if the turbine could not be stopped. Similar to that on modern propeller aircraft to turn the blades parallel to the direction of air movement when a motor is unusable, thereby reducing drag considerably....

I certainly feel that there is a lot of possible merit to the idea and I would like to see exactly what happens over the next year of so with this as it is improved and developed.

At the end of the day, the extra cost of the lens needs to be significantly MORE than offset by the efficiency increase, that has not fully been demonstrated as of now to my mind.....though I do feel that this extra efficiency is fully possible.