Venturi wind turbines

Now here's something you don't see every day.

http://machinedesign.com/article/no-more-windmills-wind-catchers-use-venturi-technique-to-generate-power-0222?NL=EET-01&Issue=EET-01_20130225_EET-01_543&YM_RID=mrdarrett@gmail.com&YM_MID=1375571&sfvc4enews=42

 

[TTman]

<mrdarrett@gmail.com> wrote in message
news:0d341c3d-b898-4e92-bb6a-2ae660938b8e@googlegroups.com...

Now here's something you don't see every day.

http://machinedesign.com/article/no-more-windmills-wind-catchers-use-venturi-technique-to-generate-power-0222?NL=EET-01&Issue=EET-01_20130225_EET-01_543&YM_RID=mrdarrett@gmail.com&YM_MID=1375571&sfvc4enews=42

I can see that taking off ! ( but not in a bad way )

 

On Monday, February 25, 2013 2:14:30 PM UTC-8, TTman wrote:

mrdarrett@gmail.com> wrote in message

news:0d341c3d-b898-4e92-bb6a-2ae660938b8e@googlegroups.com...

Now here's something you don't see every day.



http://machinedesign.com/article/no-more-windmills-wind-catchers-use-venturi-technique-to-generate-power-0222?NL=EET-01&Issue=EET-01_20130225_EET-01_543&YM_RID=mrdarrett@gmail.com&YM_MID=1375571&sfvc4enews=42



I can see that taking off ! ( but not in a bad way )

It's freaking genius. I can see the EPA maybe requiring a 2-inch-square mesh to prevent hummingbirds from being caught in the draft, but... wow. Wow. And wow. US$0.02/kw-hr, huh.

 

[John Larkin]

On Mon, 25 Feb 2013 14:00:28 -0800 (PST), mrdarrett@gmail.com wrote:

Now here's something you don't see every day.

http://machinedesign.com/article/no-more-windmills-wind-catchers-use-venturi-technique-to-generate-power-0222?NL=EET-01&Issue=EET-01_20130225_EET-01_543&YM_RID=mrdarrett@gmail.com&YM_MID=1375571&sfvc4enews=42

Looks expensive. And it will blow away in a good thunderstorm.

Does that actually work, necking down a pipe to increase air velocity?


--

John Larkin Highland Technology, Inc

jlarkin at highlandtechnology dot com
http://www.highlandtechnology.com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom laser drivers and controllers
Photonics and fiberoptic TTL data links
VME thermocouple, LVDT, synchro acquisition and simulation

 

[Tim Wescott]

On Mon, 25 Feb 2013 15:49:09 -0800, mrdarrett wrote:

On Monday, February 25, 2013 3:19:11 PM UTC-8, John Larkin wrote:
On Mon, 25 Feb 2013 14:00:28 -0800 (PST), mrdarrett@gmail.com wrote:



Now here's something you don't see every day.



http://machinedesign.com/article/no-more-windmills-wind-catchers-use-
venturi-technique-to-generate-power-0222?

NL=EET-01&Issue=EET-01_20130225_EET-01_543&YM_RID=mrdarrett@gmail.com&YM_MID=1375571&sfvc4enews=42

Looks expensive. And it will blow away in a good thunderstorm.



Does that actually work, necking down a pipe to increase air velocity?


It does, but total air flow Q = velocity * cross-sectional area, similar
I guess to how total power = voltage * current.

And, yeah, the cross sectional area at the generator is quite a bit
smaller than at the intake.

Sure looks interesting though.

It's a clever idea if it works. It'll probably be easier to make the
upper works stout when there's no moving parts -- that might offset the
extra cost of making them so _big_. Having the moving parts at ground
level means that your maintenance guys are exposed to a lot less risk,
too.

Time will tell. It'll probably garner some gov'mint money, no matter
what.

--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?

Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com

 

[Tim Williams]

Neato, and as obvious as hindsight makes it look, it's about time!

Seems to me it would suck rather than blow. If you do the old
blow-across-the-open-end-of-a-pipe trick, you get lift from the Bernoulli
effect. Specifically, the difference in wind velocity between ground
level (especially if you hide the intake within a dense forest or
something like that) and altitude causes a pressure difference

I suppose the catcher part is baffled and, perhaps, equipped with throttle
plates to shut off the non-windward sides, so only ram air travels
through. A passive structure would be possible with lightly sprung check
valves (air pressure might also provide the action), or perhaps simply
taking advantage of fluid flow (Coanda effect). If this is the case, it
leaves much of the head underutilized. I expect further improvements are
possible, and in development.

Tim

--
Deep Friar: a very philosophical monk.
Website: http://seventransistorlabs.com

<mrdarrett@gmail.com> wrote in message
news:0d341c3d-b898-4e92-bb6a-2ae660938b8e@googlegroups.com...

Now here's something you don't see every day.

http://machinedesign.com/article/no-more-windmills-wind-catchers-use-venturi-technique-to-generate-power-0222?NL=EET-01&Issue=EET-01_20130225_EET-01_543&YM_RID=mrdarrett@gmail.com&YM_MID=1375571&sfvc4enews=42

 

On Monday, February 25, 2013 3:19:11 PM UTC-8, John Larkin wrote:

On Mon, 25 Feb 2013 14:00:28 -0800 (PST), mrdarrett@gmail.com wrote:



Now here's something you don't see every day.



http://machinedesign.com/article/no-more-windmills-wind-catchers-use-venturi-technique-to-generate-power-0222?NL=EET-01&Issue=EET-01_20130225_EET-01_543&YM_RID=mrdarrett@gmail.com&YM_MID=1375571&sfvc4enews=42



Looks expensive. And it will blow away in a good thunderstorm.



Does that actually work, necking down a pipe to increase air velocity?

It does, but total air flow Q = velocity * cross-sectional area, similar I guess to how total power = voltage * current.

And, yeah, the cross sectional area at the generator is quite a bit smaller than at the intake.

Sure looks interesting though.

 

[Jeff Liebermann]

On Mon, 25 Feb 2013 14:00:28 -0800 (PST), mrdarrett@gmail.com wrote:

Now here's something you don't see every day.

http://machinedesign.com/article/no-more-windmills-wind-catchers-use-venturi-technique-to-generate-power-0222?NL=EET-01&Issue=EET-01_20130225_EET-01_543&YM_RID=mrdarrett@gmail.com&YM_MID=1375571&sfvc4enews=42

<http://sheerwind.com>
<http://sheerwind.com/wp-content/uploads/sheerwind/2012/09/SheerWind-_INVELOX-Info.pdf>
<http://www.youtube.com/watch?feature=player_embedded&v=elBntB5_TGM>
No test results, simulations, numbers, or calculations to be found
anywhere. Hmmmm...

A few problems.
1. There's not much wind at what looks from the photo to be about 8
meters off the ground. To get decent wind, one needs to be at least
20 meters or so off the ground and away from any trees and buildings.
2. Wind energy is proportional to the cube of the wind speed. The
claimed 2 mph operating point (0.9 meters/sec) can deliver about 20
watts per square meter. My guess(tm) of the intake aperature is about
3x3 meters or 9 square meters. Assuming no backpressure or frictional
losses, this thing can deliver a maximum of 180 watts at 2 mph.
3. Hopefully, this horn of plenty has a one way flap valve for each
intake. When the wind blows past a cylindrical obstruction, it
creates a partial vacuum on the far side of the cylinder. Without the
flap valves, the air will go in one intake, and out the others.
4. If this thing worked, I could install a big funnel on the front of
my car, plumb a venturi to the aft end of the car, and use the
compressed air flow to propel the car forward. Something about
conservation of energy.
5. I can't wait to hear how much noise this thing makes. Whenever
you change the direction of the wind, there's going to be noise.

See Fig 6 and 7:
<http://www.omafra.gov.on.ca/english/engineer/facts/03-047.htm>

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Artemus]

<mrdarrett@gmail.com> wrote in message
news:0d341c3d-b898-4e92-bb6a-2ae660938b8e@googlegroups.com...

Now here's something you don't see every day.

http://machinedesign.com/article/no-more-windmills-wind-catchers-use-venturi-technique-to-generate-power-0222?NL=EET-01&Issue=EET-01_20130225_EET-01_543&YM_RID=mrdarrett@gmail.com&YM_MID=1375571&sfvc4enews=42

I'm not an aero engineer but this looks like pie in the sky claims to me.
1. It appears that the intake area on this is significantly less than that of
a propeller style windmill. Therefore it can't extract the same amount
of wind energy. No?
2. There will be not insignificant loss of energy due to the aero drag on
the walls of the venturi. Compressing the air will also add to the losses.

There do appear to be some benefits, but efficiency isn't one of them.
Art

 

[langwadt@fonz.dk]

On Feb 26, 1:03 am, Tim Wescott <t...@seemywebsite.com> wrote:

On Mon, 25 Feb 2013 15:49:09 -0800, mrdarrett wrote:
On Monday, February 25, 2013 3:19:11 PM UTC-8, John Larkin wrote:
On Mon, 25 Feb 2013 14:00:28 -0800 (PST), mrdarr...@gmail.com wrote:

Now here's something you don't see every day.

http://machinedesign.com/article/no-more-windmills-wind-catchers-use-

venturi-technique-to-generate-power-0222?
NL=EET-01&Issue=EET-01_20130225_EET-01_543&YM_RID=mrdarr...@gmail.com&YM_MID=1375571&sfvc4enews=42











Looks expensive. And it will blow away in a good thunderstorm.

Does that actually work, necking down a pipe to increase air velocity?

It does, but total air flow Q = velocity * cross-sectional area, similar
I guess to how total power = voltage * current.

And, yeah, the cross sectional area at the generator is quite a bit
smaller than at the intake.

Sure looks interesting though.

It's a clever idea if it works.  It'll probably be easier to make the
upper works stout when there's no moving parts -- that might offset the
extra cost of making them so _big_.  Having the moving parts at ground
level means that your maintenance guys are exposed to a lot less risk,
too.

Time will tell.  It'll probably garner some gov'mint money, no matter
what.

I can see it being less noisy and not so many complaints from
neighbors that
don't like their house and garden turned in to a blinking disco when
the sun is low


-Lasse

 

On Monday, February 25, 2013 3:49:09 PM UTC-8, mrda...@gmail.com wrote:

On Monday, February 25, 2013 3:19:11 PM UTC-8, John Larkin wrote:

On Mon, 25 Feb 2013 14:00:28 -0800 (PST), mrdarrett@gmail.com wrote:







Now here's something you don't see every day.







http://machinedesign.com/article/no-more-windmills-wind-catchers-use-venturi-technique-to-generate-power-0222?NL=EET-01&Issue=EET-01_20130225_EET-01_543&YM_RID=mrdarrett@gmail.com&YM_MID=1375571&sfvc4enews=42







Looks expensive. And it will blow away in a good thunderstorm.







Does that actually work, necking down a pipe to increase air velocity?





It does, but total air flow Q = velocity * cross-sectional area, similar I guess to how total power = voltage * current.



And, yeah, the cross sectional area at the generator is quite a bit smaller than at the intake.



Sure looks interesting though.

Ah, extractable power is more like 1/2 * (density of air) * (cross-sectional area) * (velocity^3).

http://uni-leipzig.de/~energy/ef/15.htm

I vaguely remember power is proportional to the cube of the velocity, and there are some really nasty equations we had to use/derive back in fluid mechanics classes, but this is a good distillation of the relevant equations (and quite elegant, I must add). No macroscopic mechanical energy balances required, haha.

Michael

 

On Monday, February 25, 2013 4:26:11 PM UTC-8, Tim Williams wrote:

Neato, and as obvious as hindsight makes it look, it's about time!



Seems to me it would suck rather than blow. If you do the old

blow-across-the-open-end-of-a-pipe trick, you get lift from the Bernoulli

effect. Specifically, the difference in wind velocity between ground

level (especially if you hide the intake within a dense forest or

something like that) and altitude causes a pressure difference



I suppose the catcher part is baffled and, perhaps, equipped with throttle

plates to shut off the non-windward sides, so only ram air travels

through. A passive structure would be possible with lightly sprung check

valves (air pressure might also provide the action), or perhaps simply

taking advantage of fluid flow (Coanda effect). If this is the case, it

leaves much of the head underutilized. I expect further improvements are

possible, and in development.



Tim



--

Deep Friar: a very philosophical monk.

Website: http://seventransistorlabs.com



mrdarrett@gmail.com> wrote in message

news:0d341c3d-b898-4e92-bb6a-2ae660938b8e@googlegroups.com...

Now here's something you don't see every day.



http://machinedesign.com/article/no-more-windmills-wind-catchers-use-venturi-technique-to-generate-power-0222?NL=EET-01&Issue=EET-01_20130225_EET-01_543&YM_RID=mrdarrett@gmail.com&YM_MID=1375571&sfvc4enews=42

The website looks interesting, but it looks like they won't have product shipped until later this year...

http://sheerwind.com/

Minnesota... that's pretty close to you, Tim, right?

Michael

 

[Tim Williams]

<mrdarrett@gmail.com> wrote in message
news:fcdb2fad-936e-4027-b3b7-70a4999783e7@googlegroups.com...

The website looks interesting, but it looks like they won't have
product shipped until later this year...

http://sheerwind.com/

Minnesota... that's pretty close to you, Tim, right?

In a relative sense, yes. Digikey (Thief River Falls) ships practically
next day. But it's also a six hour drive.

For being mostly flat and midwestern, WI gets enough wind that they've
installed some turbines in various areas. As I recall there's a few
around the capitol.

Tim

--
Deep Friar: a very philosophical monk.
Website: http://seventransistorlabs.com

 

[Jan Panteltje]

On a sunny day (Mon, 25 Feb 2013 14:00:28 -0800 (PST)) it happened
mrdarrett@gmail.com wrote in
<0d341c3d-b898-4e92-bb6a-2ae660938b8e@googlegroups.com>:

Now here's something you don't see every day.

http://machinedesign.com/article/no-more-windmills-wind-catchers-use-venturi-technique-to-generate-power-0222?NL=EET-01&Issue=EET
-01_20130225_EET-01_543&YM_RID=mrdarrett@gmail.com&YM_MID=1375571&sfvc4enews=42

Bit of a storm and that whole thing will blow away.
Windmil poles do not catch much wind,
and the propellor blades can be put in neutral position.

 

On Mon, 25 Feb 2013 14:00:28 -0800 (PST), mrdarrett@gmail.com wrote:

Now here's something you don't see every day.

http://machinedesign.com/article/no-more-windmills-wind-catchers-use-venturi-technique-to-generate-power-0222?NL=EET-01&Issue=EET-01_20130225_EET-01_543&YM_RID=mrdarrett@gmail.com&YM_MID=1375571&sfvc4enews=42

The energy of the wind is directly proportional to the air density and
cross section area and relative to the third power of wind speed.

The cross section area can be the area covered by a conventional
horizontal axis wind turbine or the area covered by some vertical
construction or even the classical Savonius design.

If the structure shown in the picture is 30 m high and maybe 10 m
wide, the cross section area is only 900 m˛, why would anyone expect
it to generate 1.8 MW ? In a lossless system, that would require at
least 18 m/s wind, which is rare at 30 m above ground in most parts of
the world. The situation might be realistic a few hundred meters above
ground.

The basic flaw in arguing that a small structure would concentrate the
air into the turbine. The air is not "so stupid" that it would go
through the turbine, while it can more easily go around the
structure.

The situation is different, when the structure is kilometers wide
and/or hundreds of meters tall, e.g. a valley between two mountains or
when the air flow above a high hill, in which case the speed of air is
increased (compare this to the faster air flow above the wing of an
airplane).

 

[John Larkin]

On Tue, 26 Feb 2013 20:32:06 +0200, upsidedown@downunder.com wrote:

On Mon, 25 Feb 2013 14:00:28 -0800 (PST), mrdarrett@gmail.com wrote:

Now here's something you don't see every day.

http://machinedesign.com/article/no-more-windmills-wind-catchers-use-venturi-technique-to-generate-power-0222?NL=EET-01&Issue=EET-01_20130225_EET-01_543&YM_RID=mrdarrett@gmail.com&YM_MID=1375571&sfvc4enews=42

The energy of the wind is directly proportional to the air density and
cross section area and relative to the third power of wind speed.

The cross section area can be the area covered by a conventional
horizontal axis wind turbine or the area covered by some vertical
construction or even the classical Savonius design.

If the structure shown in the picture is 30 m high and maybe 10 m
wide, the cross section area is only 900 m˛, why would anyone expect
it to generate 1.8 MW ? In a lossless system, that would require at
least 18 m/s wind, which is rare at 30 m above ground in most parts of
the world. The situation might be realistic a few hundred meters above
ground.

The basic flaw in arguing that a small structure would concentrate the
air into the turbine. The air is not "so stupid" that it would go
through the turbine, while it can more easily go around the
structure.

Right. The necking down will increase velocity, but also make back
pressure that will reduce the intake volume.

Seems silly.


--

John Larkin Highland Technology, Inc

jlarkin at highlandtechnology dot com
http://www.highlandtechnology.com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom laser drivers and controllers
Photonics and fiberoptic TTL data links
VME thermocouple, LVDT, synchro acquisition and simulation

 

[amdx]

On 2/25/2013 7:02 PM, Jeff Liebermann wrote:

On Mon, 25 Feb 2013 14:00:28 -0800 (PST), mrdarrett@gmail.com wrote:

Now here's something you don't see every day.

http://machinedesign.com/article/no-more-windmills-wind-catchers-use-venturi-technique-to-generate-power-0222?NL=EET-01&Issue=EET-01_20130225_EET-01_543&YM_RID=mrdarrett@gmail.com&YM_MID=1375571&sfvc4enews=42

http://sheerwind.com
http://sheerwind.com/wp-content/uploads/sheerwind/2012/09/SheerWind-_INVELOX-Info.pdf
http://www.youtube.com/watch?feature=player_embedded&v=elBntB5_TGM
No test results, simulations, numbers, or calculations to be found
anywhere. Hmmmm...

Hey Jeff, it does say they tested a 0.3 watt unit.

"The first small scale field unit, rated 300 mW was designed and
constructed last year and validated the CFD models predictions. A larger
scale field demo unit rated 1.5 kW to 5 kW also went live last year. "

I wonder if the pictures shown are the 1.5 kW unit mentioned above.

Mikek

 

[tm]

"John Larkin" <jlarkin@highlandtechnology.com> wrote in message
news:9o0qi81m9db261bie7f22d6rcgpi8ucaiu@4ax.com...

On Tue, 26 Feb 2013 20:32:06 +0200, upsidedown@downunder.com wrote:

On Mon, 25 Feb 2013 14:00:28 -0800 (PST), mrdarrett@gmail.com wrote:

Now here's something you don't see every day.

http://machinedesign.com/article/no-more-windmills-wind-catchers-use-venturi-technique-to-generate-power-0222?NL=EET-01&Issue=EET-01_20130225_EET-01_543&YM_RID=mrdarrett@gmail.com&YM_MID=1375571&sfvc4enews=42

The energy of the wind is directly proportional to the air density and
cross section area and relative to the third power of wind speed.

The cross section area can be the area covered by a conventional
horizontal axis wind turbine or the area covered by some vertical
construction or even the classical Savonius design.

If the structure shown in the picture is 30 m high and maybe 10 m
wide, the cross section area is only 900 m˛, why would anyone expect
it to generate 1.8 MW ? In a lossless system, that would require at
least 18 m/s wind, which is rare at 30 m above ground in most parts of
the world. The situation might be realistic a few hundred meters above
ground.

The basic flaw in arguing that a small structure would concentrate the
air into the turbine. The air is not "so stupid" that it would go
through the turbine, while it can more easily go around the
structure.

Right. The necking down will increase velocity, but also make back
pressure that will reduce the intake volume.

Seems silly.


--

Well there you go. Obozo will fund it if they kick some of the money back.

 

[Jeff Liebermann]

On Tue, 26 Feb 2013 13:12:11 -0600, amdx <amdx@knologynotthis.net>
wrote:

On 2/25/2013 7:02 PM, Jeff Liebermann wrote:
On Mon, 25 Feb 2013 14:00:28 -0800 (PST), mrdarrett@gmail.com wrote:

Now here's something you don't see every day.

http://machinedesign.com/article/no-more-windmills-wind-catchers-use-venturi-technique-to-generate-power-0222?NL=EET-01&Issue=EET-01_20130225_EET-01_543&YM_RID=mrdarrett@gmail.com&YM_MID=1375571&sfvc4enews=42

http://sheerwind.com
http://sheerwind.com/wp-content/uploads/sheerwind/2012/09/SheerWind-_INVELOX-Info.pdf
http://www.youtube.com/watch?feature=player_embedded&v=elBntB5_TGM
No test results, simulations, numbers, or calculations to be found
anywhere. Hmmmm...

Hey Jeff, it does say they tested a 0.3 watt unit.

Milliwatts, Megawatts... what's a few zeros worth these days?

"The first small scale field unit, rated 300 mW was designed and
constructed last year and validated the CFD models predictions. A larger
scale field demo unit rated 1.5 kW to 5 kW also went live last year. "

I wonder if the pictures shown are the 1.5 kW unit mentioned above.
Mikek

Let's do the math. The question is 1.5 KW at what wind speed? My
guess(tm) is that the aperture size is 3 x 3 meters or 9 square
meters. Ignoring all losses and inefficiencies, in order to produce
1.5 KW, one needs a wind speed of approx:
Watts/sq-meter = 0.6 * (meters/sec)^3
(meters/sec)^3 = (1500 / 9 / 0.6)^0.333 = 6.5 meters/sec
wind (15 mph) at about 8 meters altitude. That's possible, but not
easy at such a low intake altitude, I doubt that there would be too
many places where such a minimum wind speed could be sustained
24x7x365. Perhaps a few days per year on some mountain top
(conveniently lacking trees) might work. Ignoring losses is also a
bad idea as I suspect the backpressure from using wind as an air
compressor is substantial.

Average wind speed for various US airports. Airports usually don't
have trees obstructing the approach. The anemometer is usually on the
control tower roof, which might be a bit higher than the Sheerwind
thing, but close enough:
<http://www.wrcc.dri.edu/htmlfiles/westwind.final.html>


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[mike]

On 2/26/2013 11:12 AM, amdx wrote:

On 2/25/2013 7:02 PM, Jeff Liebermann wrote:
On Mon, 25 Feb 2013 14:00:28 -0800 (PST), mrdarrett@gmail.com wrote:

Now here's something you don't see every day.

http://machinedesign.com/article/no-more-windmills-wind-catchers-use-venturi-technique-to-generate-power-0222?NL=EET-01&Issue=EET-01_20130225_EET-01_543&YM_RID=mrdarrett@gmail.com&YM_MID=1375571&sfvc4enews=42


http://sheerwind.com
http://sheerwind.com/wp-content/uploads/sheerwind/2012/09/SheerWind-_INVELOX-Info.pdf

http://www.youtube.com/watch?feature=player_embedded&v=elBntB5_TGM
No test results, simulations, numbers, or calculations to be found
anywhere. Hmmmm...

Hey Jeff, it does say they tested a 0.3 watt unit.

"The first small scale field unit, rated 300 mW was designed and
constructed last year and validated the CFD models predictions. A larger
scale field demo unit rated 1.5 kW to 5 kW also went live last year. "

I wonder if the pictures shown are the 1.5 kW unit mentioned above.

Mikek

I'd ask 'em the same thing I'd ask Rossi,

"why is it so difficult to prove it?"

Build a uni-directional one out of plywood.
Bolt it to a flatbed truck, or on top of a bus.
Drive it down the road.
Measure volume/pressure with speed as a parameter.
If you like the numbers, stick a generator in it.
Then go solve all those pesky issues with omnidirectional behavior.

If you can't make it work on a truck driving down the road at
2 or 20 or 60 MPH,
there's no need to pursue it further.

That'd be far more useful than a 300mW prototype.
And you could work on it where there's no wind.
And it'd cost far less and take less time than setting up their website.
But it'd garner fewer greedy/uninformed investors.