The Future of Wind Turbines? No Blades?...

[Seth]

Let's face it, if you came up with a better wind turbine, it would be worth billions.

The fact that this has attracted not much over a million must mean something.

But good luck to them. I hope it's a success.

One should remember that the windmill lobby is enormous worldwide and it's been slopping at the government trough for a long time now and wields a lot of political and economic influence.

Obviously this is a startup and I'd like to see it succeed because their system, if it works, is far better than 300 foot tall windmills cluttering up the horizon everywhere you look. It's still a visual blight, but at least they are relatively short, can be painted to reduce their visual impact, and don't kill birds...although I'd be interested to see how they might be affected by birds landing, sitting, roosting or nesting on top of them. I think some sort of anti-bird spikes will be necessary.

[mistermack]

The Spanish video talks about using fluid to spin the generator.
Which implies this is the same or similar device I saw in 2010 in which the wind-powered movement of the "frond" pressurizes a hydraulic accumulator. It's the pressurized fluid that spins the generator which produces (induces) the juices.

Sounds inefficient.
You don't get many hydraulic drives, where efficiency and energy conservation are important.

There tends to be a lot of energy lost to drag.

Another problem with this design, is that it only sweeps a small area of wind, compared to spinning blades, so the available energy is small for each one.
You would need an awful lot more of them, in the same ground space as one conventional wind turbine.

[pErvinalia]

Remember, at any given point in time on a regular turbine, there is only three times the surface area of one blade interacting with the wind. Depending on the size of the upright pole type "turbine", those sizes are probably pretty similar. Certainly not that great a difference, I would guess.

[mistermack]

Remember, at any given point in time on a regular turbine, there is only three times the surface area of one blade interacting with the wind. Depending on the size of the upright pole type "turbine", those sizes are probably pretty similar. Certainly not that great a difference, I would guess.

Doesn't quite work like that. The speed of the blade rotation comes into it, effectively increasing the wind speed over the surface. The quantity of air per second passing over each square centimetre of the blade is much higher in the conventional turbine. So there is far more energy available than from just the static blade area.

[pErvinalia]

I don't know that that's right. I'm going to have to think about this some more. Sounds awfully like you are getting free energy. Remember, it's the wind itself which is rotating the blades, not an engine.

[mistermack]

I don't know that that's right. I'm going to have to think about this some more. Sounds awfully like you are getting free energy. Remember, it's the wind itself which is rotating the blades, not an engine.

Yes, but the rotation allows the blade to cover a much greater area of air in a given time.
Check out that trolley that the wind drives upwind or downwind faster than the wind, to see some of the principles involved.

[pErvinalia]

Actually, thinking about this more, the area being worked on by the wind in a conventional wind turbine is smaller than the surface area of the blades. The blades work like wings, as you'd know, so the air is actually only working on the frontal surface area (i.e. the thin part of the wing slicing through the air). So the effective surface area of a conventional wind turbine would be much smaller than the surface area of the tube type turbine. Anyway, it's all going to come down to the efficiency of the energy transfer from the wind to the turbine. Per surface area the tube thingy might well be less efficient (but it could be more for all we know) than a conventional turbine, but it has significantly more surface area. And consider, the whole tube, including the full outside surface area and potentially some of the inside surface area is going to play into the process. And looking at some of those mock ups, it seems that there is a frame like structure to them too, which would increase the surface area even more.

[pErvinalia]

Check out that trolley that the wind drives upwind, to see some of the principles involved.

I think you mean "downwind". Moving upwind with a turbine is going to be trivially easy.

[mistermack]

It's not down to the surface area of the tube.

A given area of space, facing the wind has a fixed amount of available energy.
No matter what lateral area the tube has, it can't increase the cross section facing the wind.
Whereas the spinning blade effectively does that, in real time.

[mistermack]

Check out that trolley that the wind drives upwind, to see some of the principles involved.

I think you mean "downwind". Moving upwind with a turbine is going to be trivially easy.

Yeh, I realised that after I posted it, so I edited it.
It's a similar principle though. A fixed blade could never take energy from the wind, at the same speed as the wind. It's the spin that increases the swept effective area.

[pErvinalia]

It's not down to the surface area of the tube.

A given area of space, facing the wind has a fixed amount of available energy.
No matter what lateral area the tube has, it can't increase the cross section facing the wind.
Whereas the spinning blade effectively does that, in real time.

The rotation does increase the wind speed going over the turbine "wing", and even assuming that that's a net increase in deliverable energy, that still doesn't mean it's automatically making more energy than the tube turbine at any instant in time. I'm not sure why you are talking about "lateral" area of the tube. As I said, the WHOLE structure surface area would be playing a part. Turbulence effects will impact on the leeward surface, so all surface would be acted on.

[pErvinalia]

Actually, having said that, the whole area of the blade "wing" is being acted on too in a sense.

Basically, we are comparing apples to oranges here. They each work by a different mechanism. So comparing surface areas and the like is not really going to enlighten us much.

[mistermack]

Yeh, it's a very technical field.
Basically, what I'm saying is that to measure the energy stored in the wind, you measure the flow rate through a fixed area, at right angles to the wind.
You can't increase the energy that's in the wind, except by increasing the area that you exploit. Each square foot only has a certain amount of energy available.

So if you put ten turbines, one in front of the other, down the wind, you can't extract any more energy than was in the wind to start with. If you place them sideways, across the wind, then you can get ten times the energy.
It's down to the amount of wind you intercept.

[Tero]

Where is the parody thread about "turd windbines" ?

[Hermit]

Go and Suture a Wound Turban, Tero.