Bladeless wind turbines--big and small

[ERD50]

Trees sway in the wind. ...

Sure, but is that the optimal configuration?

These guys don't strike me as dummies. For now I'll assume that if adding 'branches' to that structure would improve the power output, they would have designed it with 'branches'.

-ERD50

 

[samclem]

I'm guessing the energy is harvested with a disk towards the base (he pointed to the linear alternator as being ~ 1/4 of the way up I think). I picture the disk/magnets being horizontal, and the coils in a fixed toroidal arrangement above and below the disk, so any movement of the disk has the magnets moving in relation to those coils and creating a current.

I'm trying to figure out what type of setup could harvest an appreciable amount of electrical energy from such a slow, high-torque mechanical motion--without using gears to get the speed of the armature (or magnets) up. It would seem to me that, without high speeds, the coils and magnets would have to be very robust to produce appreciable electricity. The info from the company mentioned some type of electronics that artificially mimic mechanical gearing.

It's impressive that these three guys hit on two complementary and apparently novel ideas simultaneously--this vertical mast that produces the oscillatory motion due to wind/vortices, and the electromechanical means to turn that relatively slow motion into electricity. I'm pretty sure this won't be the final evolution of this concept, but it's pretty cool as-is (if it's even close to the claims).

 

[Midpack]

Lots of fascinating approaches being explored - though cost, "energy" storage and intermittent sources remain the larger obstacles (vs generating while sources are available) IF we expect to maintain our current 24/7 access to "energy."

Reading the discussions here reminds me: All truth passes through three stages: First, it is ridiculed; Second, it is violently opposed; Third, it is accepted as self-evident. - Arthur Schopenhauer

Saphon Energy

 

[ERD50]

Lots of fascinating approaches being explored - though cost, "energy" storage and intermittent sources remain the larger obstacles (vs generating while sources are available) IF we expect to maintain our current 24/7 access to "energy."

Saphon Energy

Interesting - this video shows that it 'wobbles', I guess it fills with air, tilts to the side to release that air, then re-centers to be filled again. Three pistons capture the energy electro-magnetically.

... Reading the discussions here reminds me: All truth passes through three stages: First, it is ridiculed; Second, it is violently opposed; Third, it is accepted as self-evident. - Arthur Schopenhauer

I'm not following you, unless you are trying to say this idea does not represent 'truth'. Where is the ridiculing and opposition?

I see questions about how they generate the electricity, questions about stresses, but no ridicule or opposition.

At any rate, I think that quote is overused and misused. I don't think all truths or new ideas are ridiculed (overall that is - you will always find someone who is opposed to any idea). Many good ideas are accepted very quickly. Did the general public ridicule the idea of, hmmmmm, recording TV shows at home for later playback? Carrying a telephone with you? Carrying your music with you? Portable computers?

And misused because not every idea that is ridiculed ends up being a 'truth' or a good idea. Yet many people tend to think this way.

-ERD50

 

[ERD50]

Oscillations can bring down bridges and buildings...seems like a lot of energy?

From wiki:



Collapse of the Tacoma Narrows Bridge


Tacoma Narrows Bridge Collapse Tacoma, Washington
November 7, 1940
by Rachel Martin
...

Looking back at the Tacoma Narrows bridge collapse, the energy was due to flutter, similar to these blade-less designs.

https://en.wikipedia.org/wiki/Aeroelasticity

In the bridge, the flutter worked with the 5 second period of resonance of the bridge. So it takes relatively little forces to create large displacements when that force is in-sync with the resonance of the system. Just like a large pendulum swings wide with very, very little pushes an each swing.

So the fact that the bridge collapsed does not say all that much about the forces involved, it says more about those existing for a long time (I think they said it was about an hour between when the oscillations were first observed and the collapse), and the flutter working in-sync with the resonance of the bridge.

Once you try to draw power from that resonance, you dampen it (lower the Q in engineering terms).

-ERD50

 

[Fermion]

Once you try to draw power from that resonance, you dampen it (lower the Q in engineering terms).

-ERD50

True, but I imagine it still would have been a fairly large electric motor to cause that many tons of concrete and steel to oscillate several meters and with up to a 45 degree twist. That has to generate heat in the steel which is drawing off some of the energy.


Even with resonance, there was probably several hundred kilowatts (maybe megawatts) of energy being absorbed by the Tacoma Narrows bridge in the 42mph wind.


It does now give me the idea of designing a windmill based on a poorly damped suspension bridge.

 

[Mulligan]

In the postscript, I corrected myself when I observed that the vibrating structure - indeed not an airfoil in the normal sense which is designed to avoid creating vortices - is symmetrical and will respond to wind from all directions. I also wondered how their "linear" generator would respond to oscillations in different vertical planes.

Anyway, any novel new design will avoid existing limitations just to create some new problems. And the designer will not discover them until he tries. And people will have to try, else we would be stuck with horse-drawn carriages. I am not a naysayer, but just try to figure out what problems he will have to solve.

And talk about vertical wind structures, how about more conventional designs like the following? I looked at a few that have been in production, figuring that if one is inexpensive enough I would buy a small one to play with in my high-country home which has lots of wind. They are more expensive than conventional turbines!

The world should be thankful it is not all populated with people such as myself. I can hear myself now if I had lived in previous times... "Nothing will ever replace the spear to kill our food".... "This automobile thing will never replace a good horse"...." These personal computer things are a fad and will soon too pass".


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