MAR 26

I have always wondered why aeronautical engineering was not more involved in the design of windmills. It looks like it has a lot of potential--if the engineering works out. This would be a natural for carbon fiber construction.

A side from that - it looks pretty interesting. Though that video seems to spend more time telling us why the old design aren't very good rather than telling us the new ones good points.

Hey thanks for the great blog, love this stuff. I don’t usually do much for Earth Day but with everyone going green these days I thought I try to do my part.

I am trying to find easy, simple things I can do to help stop global warming (I stress easy, I don’t plan on going out and buying a hybrid). I took the Earth Day Challenge that EarthLab.com is promoting ( http://www.earthlab.com/ ) and I am planning on lowering my score. They have some pretty good tips (they call them pledges).

I am looking for more easy fun stuff to do. If you know of any other sites worth my time let me know.

I dowloaded the AIAA paper on their site. This thing IS a game changer. They have addressed all the reasons prior shrouded designs failed! I wish I thought of it!

Whats the danger to wildlife? I can imagine something getting sucked in and breaking this thing. Nice idea though.

No more danger than previous wind turbines i guess..

Modern large scale wind turbines run at better than 90% of the ideal efficiency. That ideal is itself nearly 60% of the total wind energy by area traced.

Someone who's saying they can triple that is saying they're collecting better than 150% of the total wind energy, which must involve gaining energy by stopping it, then gaining some more by restarting it. Clever that.

Anyone who believes it needs to go over the laws of thermodynamics some more. A lot more. Until you get it. Either way, do not give this con man your money.

Though, obviously, they haven't tested these things in the field yet, there's some signs that they will be less damaging to wildlife. Because of the speed of the tips of traditional prop turbines, it's difficult for birds to actually see them. These will appear to birds as static, so they will be easier to avoid. Birds and bats don't generally fly int what they can see. Though, of course, we'll have to wait and see. Cell towers are also static and definitely contribute somewhat to bird mortality.

I don't understand the fluid dynamics or other science going on here but am curious that with the intersected area being so much less than a regular turbine it could recover so much useful energy.

@Tussock
I'm guessing the three to four times more energy estimation is being calculated not per turbine which as you say is physically impossible but by land area. They claim that they can put these turbines much closer together which implies that they can capture more energy per hectare. Does that make any sense?

Yep, 3-4 times the energy by land area. I'm impressed by the much wider range of wind speeds that are usable by this design.

These blades spin up to much higher speeds--like a gas turbine or steam turbine. The "vortices" generated behind the blades are simply a way of increasing pressure differential on either side of the fan blades. This draws more air through the blades.

If you know anything about gas turbines, you'll understand at least part of the design advantage.

I am very impressed if they can make these work. Texas is covered with wind farms, which makes you feel good. However, when you see the "oversize load" truck in front of you and it's only carrying the very tip of the prop. It really makes you think these windmills should be a little smaller.

Hey! I participated in earth hour last night,and i was wondering if you knew of any statistics that show the effect it had on CO2 emmissions. If you do, it would be great if you posted them!

This might all be well and good for the power generation company and the manufacturer of the wind generators, but we have to face the fact that generation of energy in this way is theft. The people downwind of the generator are being denied their wind rights. If wind generators become very commonplace then I expect to see legal action taken over wind theft.

:sigh: The limits on wind power are proportional to the vertical area swept by the blade, a cross section of the moving air. We are already running above 90% of that limit.

Land area isn't particularly useful as a measurement of any kind, unless your towers are low enough to make it unavailable for other uses. Here in NZ we put farmland under them, as the ground-level air isn't efficient anyway.

Cross-sectional area * air density * velocity^3 * time.

That's the wind energy of an air stream moving through a vertical area. Generating energy with the blade takes energy from the air stream, and we're already very near the limits of how much can be taken. Laws of thermodynamics, people; vortexes don't create energy, they use it.

@Tussock
I had a gut feeling you were right. Hank gets a bit carried away with some of these press releases and I just got caught up in the moment too.
The combination of smaller turbines and less land use would be useful in some (limited) situations but the promises here are obviously too good to be true if we're already seeing 90% utilisation with regular turbines.
Thanks
Josh

This design actually pulls in a greater volume of air due to the clever use of pressures at different points within the system. The video clearly explains this principle. This means that the turbine can actually grab more energy than an equivalent bladed design with the same vertical area swept by the blade because it's pulling in more air into the same area.

However, the 3x improvement claim is still only correct if you compare the two systems in the right way.
Comparing it by land area appears valid to me but I would be surprised if you could space these things 1/3rd of the distance apart. However, for the same sized wind farm, you can extract some amount of extra energy out of the wind. That means something to me.

Also, if this thing can run at a greater variety of wind speeds, they may be including the extra time it is possible to run the new turbine in the calculation.

If you add the increased energy extraction per unit of land area and the larger variety of wind speeds this turbine can run in I suspect you will get close the a 3x improvement in output from a single windfarm.

As far as litigation from people downwind from a wind farm is concerned, I doubt that they'll get anywhere. Firstly, they would have to prove that they are actually receiving less wind and that the amount of wind they are not receiving is actually causing them harm. Secondly, the damages will only be proportional to the damages the lack of wind actually causes them, which will be almost negligible. We're not talking about a completely calm day when everywhere else is getting 20 knots. We're talking about these guys getting 19.9 knots when everywhere else is getting 20 knots.

I think it is a clever looking design...but gosh it uses a lot of material for the amount of area swept...maybe this is better than other shroud designs, but does the extra energy from the air speed/versatility provide greater value than the extra material cost?
Time will tell.

Even if this delivers exactly the same power at a given wind speed the other benefits would make it worth while to pursue. Being safelyusable at slower and higher speeds, and transportable on one truck vs many sounds like a design improvement worth making this something to look at.

This is really just a trade-off: High-torque (long, slow blades) vs. high-horsepower (shorter, faster blades). The vortex generation bit is simply an attempt to couple more wind energy into the blades; but as the wind speed increases, the apparent wind angle will change---and that will change the efficiency of the FloDesign turbine. Finally, the larger diamater of the after tube is just taking advantage of the Bernoulli principle to `suck' more air through the turbine. As far as safety is concerned, the higher rotational speeds of the FloDesign might actually present greater damage potential than the slower long blade.

It's the old trade-off of high torque (long, slow blades) vs. high horsepower (fast, short blades). Let's see actual power generated comparisons.

It's the old trade-off of high torque (long, slow blades) vs. high horsepower (fast, short blades). Let's see actual power generated comparisons.

I'm more interested in the noise pollution. I know in my computer a larger, slower spinning fan is quieter than a small turbine style fan. I could only imagine the noise from acre's of these things humming along...

so far this is hot air. where is the prototype? where are any performance data? who has built one? where is it?
what is it?
so far - nothing.

Whoever is blithering about we already have 90% efficiency from standard wind turbine, is completly missing the point of these. You need your head deflating.
They are saying they are 3-4 times more efficiant, because they can run at any wind speed, in any direction, and can be placed closer together, nearer residential areas. They cost less to build and maintain apperantly too.
Why are there so many apparent more intelligent people here that have taken one look at this video and already decided that these will not work, or are not more efficient.
Considering some institute has invested half a million into this suggests people that know what there talkin about think its a good idea.

tussock. Have you actually listened to the video and read the reports on this?
I quote your comment:
'Laws of thermodynamics, people; vortexes don't create energy, they use it'
They do not use the energy from the vortex it creates, this was explained so that it dissapates the energy so that they can be placed closer together. With the old 'fashioned' designes because they 'block' the on-comming wind, turbines have to be placed further away so they can use the power from the wind.
If you are so smart, please go away and design somthing better than this.

This makes me laugh out loud! Lets trade our planet for the potential law suits that might (lol) occur from 'wind stealing'. You are basically suggesting that we not use wind farms at all. Why are people so negative about this change in design?

Torque is a static rotational quantity, whereas, Horsepower is a linear quantiy with a time component mixing the two can be done and is done regularly in the automotive world. My confusion comes when those massivly long blades are not used for their torque, because in the nacelle they turn a generator which is regulated to a very precise number of rotations. The Windflo is designed to use its higher revolutions to turn a generator as fast as possible, which if done correctly will be far more efficient.

The fluid dynamics are sound. I would love to see a prototype.

BTW more squirrels are killed crossing the road everyday than all the birds in the world killed by wind turbines. So who's watching out for the squirrels?hmmmmmmm?

As for the downwind lawsuits...you probably didn't recieve your Christmas presents due to potential liability issues either.

During the past few days I've been reading some very thorough papers on wind energy. I've learned several things in the process.

Wind is kinetic energy and contains a theoretical amount of energy calculated by the swept area (square meters or feet) and wind speed.

"The kinetic energy of wind is related to its velocity. This relationship is represented mathematically by the following equation:
P = ½ × ρ × A × V 3 , (D.1)
where
P = wind power (W),
ρ = air density (typically 2.70 lb/m3 [1.225 kg/m3] at sea level and 59̊F [15̊C]),
A = cross-sectional area of the wind being measured (m2), and
V = mean velocity of the wind within the measured cross section (m/s).
A careful examination of this power equation reveals the following important fundamental truths about wind energy. Both the air’s density and the cross-sectional area of the wind being intercepted have a direct relationship to wind power. The air’s density varies with temperature, elevation, and humidity, but, in all instances, the density remains relatively low. Thus, any changes to air density have a minimal effect on the wind’s inherent power. Doubling the crosssectional area of a wind front leads to a doubling of the intrinsic power. Most important to wind farmers is the fact that the wind’s power is proportional to the cube of its average velocity. Thus, a doubling of the average or mean wind speed results in an eightfold increase in its power.

Intercepting the greatest practical cross-sectional area of wind creates the opportunity for capturing the greatest amount of energy; therefore, the primary design focus is on the rotor, which is the part of the turbine that actually extracts the wind’s energy. No mechanical device, including the wind turbine, is 100% efficient. The practical efficiency of a wind turbine is usually represented as its power coefficient, Cp, defined as that fraction of the wind power that may be captured by the turbine and converted to mechanical work (and, subsequently, electricity). The power coefficient of a wind turbine is almost entirely a function of the rotor’s efficiency. The power coefficient is represented by the following expression:
P = ½ × Cp × ρ × A × V 3, (D.3)
where
P = power output of the turbine,
Cp = power coefficient of the rotor,
ρ = air density (typically 2.70 lb/m3 [1.225 kg/m3] at sea level and 59̊F [15̊C]),
A = rotor-swept area, and
V3 = cube of the incident wind speed.

The power coefficient of the rotor has a theoretical maximum value of 0.593, called the Betz limit or Lancaster-Betz limit. This value is based upon the physical reality that even the most aerodynamically efficient turbine blade disrupts the airflow of incident wind, even before the wind front reaches the rotating blade. In actuality, the air molecules within the cross-sectional area swept by the rotor slow down as they approach rotating turbine blades and thus lose kinetic energy proportional to the cube of that velocity loss. The power coefficient of the rotor can be thought of as a correction factor, introduced into the above power equation to reflect the reality that the rotor’s power-capturing efficiency is less than perfect. To calculate the power coefficient of the entire wind turbine, one simply has to introduce additional correction factors to represent the mechanical inefficiencies of the entire turbine drivetrain. However, for the purpose of this discussion, the power coefficient of the rotor is the source of greatest turbine inefficiency to the extent that drivetrain inefficiencies need not be discussed in detail.

http://windeis.anl.gov/documents/fpeis/maintext/Vol2/appendices/appendix_d/Vol2AppD_1.pdf

Wind turbines extract energy by slowing down the wind. For a wind turbine to be 100% efficient it would need to stop 100% of the wind - but then the rotor would have to be a solid disk and it would not turn and no kinetic energy would be converted. On the other extreme, if you had a wind turbine with just one rotor blade, most of the wind passing through the area swept
by the turbine blade would miss the blade completely and so the kinetic energy would be kept by the wind.

Betz Limit:
Albert Betz was a German physicist who calculated that no wind turbine could convert more than 59.3% of the kinetic energy of the wind into mechanical energy turning a rotor. This is known as the Betz Limit, and is the theoretical maximum coefficient of power for any wind turbine.

Good wind turbines generally fall in the 35-45% range.

http://www.kidwind.org/PDFs/SUPPORT_Math_Coefficient of Power.pdf

I am glad I found this site, I was just thinking about some new way to create power today and jet engine was exactly what I think can generate more power, as it does in jet engines. This gave me some hope as plane evolution, wind turbine evolution will go the same way. I am just disappointed that I was not the first one who thought about this. :)

Notice the swept area size of the standard prop(about 95m diameter) compared to the swept area of this thing - 10m2? ) Thats a shed load of wind area being missed. try to build one of these with a swept area of 95m in diameter. It would be enormous, and far too heavy to stick on a pole up in the air. It is bound to be more efficient at capturing the wind going through it, but has such a small swept area it will never compete with a standard prop design.
Notice in the video also how the prop desig is shown the wind being forced around it cos of the high pressure area building up in front. THIS IS CONVENIENTLY MISSED IN THE ANIMATION FOR THE FLOWDESIGN TURBINE. But it would still happen Just the same for both designs. Even with those fancy after-burner intake nozzles.

Why not mount the apparatus horizontally several meters above grade and "scoop" the wind into it? If the wind became too high, the scoop could be shuttered. If there was enough heighth to the installation, warm air rising into cooler air above could add to the wind speed. I have been around nuclear plant cooling towers and three is a nice breeze blowing into them at all times