Venturi wind turbine

[Richard]

I can't help thinking the turbine below is trying to create something from nothing. The idea is that it takes high volume low velocity air, accelerates it through a venturi and heh presto! 40 mph wind to drive a turbine.

Surely Bernoulli would roll in his grave at this one?

http://inhabitat.com/sheerwinds-invelox ... -turbines/

[youtube]http://www.youtube.com/watch?v=m7xGGt-8EnE[/youtube]

[hollus]

Feliks suggested something very alike here before:
http://www.f1technical.net/forum/viewto ... &start=191

Bernoulli would, quite literally, be blown away in his grave. There is no manufacturing of energy, of course, just concentration thereof. Although that exhaust diffuser is best designed by Adrian Newey and placed in a very favorable downwind position.

I recently travelled a lot through Denmark and northern Germany, and everytime (that was very often!) i saw a white, tall, slender windmill i could not avoid thinking of the all too frequent mine shafts (and accompanying tower) from my birth place as the alternative. Why, why oh why do we not make many, many more of those low CO2 engineering marvels?

All that is between us and virtually free energy is the lack of a practical energy storage medium.

[bhall]

Reminds me of these...



For only $100, you too can increase the weight of your car by several grams!

[coaster]

They sunk a few bucks into the prototype, my guess is a rich eccentric with an I.Q similar to average joe made it happen.

[MOWOG]

All that is between us and virtually free energy is the lack of a practical energy storage medium.

While some are snickering up their sleeve about people of ordinary intelligence, work on how to store the energy created by wind/solar/tidal facilities is proceeding at a feverish pace around the globe. In fact, in 2011, Apple filed a patent application for just such a system. See link below

http://cleantechnica.com/2013/01/05/app ... e-concept/

Newer photovoltaic technology harvests not only sunlight in the visible spectrum but also radiational energy that kicks in once the sun sets.

What wonders await the world, we cannot know. But one of the simplest ideas is to use the abundance of power produced during daylight or high wind conditions to pump water uphill to a storage tank (Think Lake Mead, here! ) and then let it run back downhill to power turbines when the light dims or the wind decreases.

The world will one day have a gigantic PERS device - Potential Energy Recovery System!

[Richard]

I think the sniggering is the idea that a venturi magically enables someone to generate power.

My hazy recollection of hours in the undergraduate lab is that a venturi needs a pressure differential between entry and exit.
That differential causes the air to flow through the venturi. I can see that air might be captured at the top of the funnel and brought to a lower level like the windcatchers in traditional Persian houses. http://en.wikipedia.org/wiki/Windcatcher

However those windcatchers take advantage of the pressure difference between the leeward and windward faces of the house. That pressure difference doesn't occur with the device shown above, the exit and entrance are in the same open space. There might be a small pressure difference due to quicker moving air at the top of the funnel compared to ground level, but I can't see it being enough to be meaningful.

So while Venturi may be useful for accelerating air and that might make a turbine more efficient, I just can't see how any air gets into the tube in the first place.

[langwadt]

I think the sniggering is the idea that a venturi magically enables someone to generate power.

My hazy recollection of hours in the undergraduate lab is that a venturi needs a pressure differential between entry and exit.
That differential causes the air to flow through the venturi. I can see that air might be captured at the top of the funnel and brought to a lower level like the windcatchers in traditional Persian houses. http://en.wikipedia.org/wiki/Windcatcher

However those windcatchers take advantage of the pressure difference between the leeward and windward faces of the house. That pressure difference doesn't occur with the device shown above, the exit and entrance are in the same open space. There might be a small pressure difference due to quicker moving air at the top of the funnel compared to ground level, but I can't see it being enough to be meaningful.

So while Venturi may be useful for accelerating air and that might make a turbine more efficient, I just can't see how any air gets into the tube in the first place.

The energy in wind is proportional to speed and area, so the intake needs to be big and at low wind speed there isn't much energy how ever you pipe it around

their claims of 600% more energy sounds like crazy talk, it might work better than a conventional wind turbine at some
low speed, but I believe at peak conventional wind turbine are approaching something like 80% of what is theoretical possible to extract from the wind

[hollus]

The arrows with wind coming in from the left and from the right at the same time are probably not accurate. But with the funny deflector, no matter where the wind comes from, some of it will be deflected downwards. Then you can think of it as a giant funnel, forget Venturi and think of ram effect. If the intake area is big enough and the channel small enough, it will work. The diffuser is there to prevent stall, and, as long as it is small enough compared to the intake area, can be right next to it. Think that the wind just outside the intake will enthrain wind just inside the intake, which then will have to go through the channels, barring a monstruous backpressure.
Efficient? Not sure...

[MOWOG]

i am not so silly as to believe in the 200 mpg carburetor, the Tooth Fairy or the truthfulness of US presidents. The claims made by the inventors are a bit, ummmm, fantastical, to say the least. Here is a quote from an article about this miracle machine as reported at Gizmag.com:

As to the sixfold output claim, as with many new technologies promising a performance breakthrough, it needs to be viewed with caution. SheerWind makes the claim based on its own comparative tests, the precise methodology of which is not entirely clear.

"We used the same turbine-generator (with a given load bank) and mounted it on a tower as is the case for traditional wind mills," SheerWind told Gizmag. "We measured wind speed and power output. Then we placed the same turbine-generator system (subjected to the same load), again we measured free stream wind speed, wind speed inside the INVELOX, and power. Then we used the power-speed relationship over 5 to 15 days (depending on the test), and calculated energy in kWh. Six hundred percent more energy was for one of the days. [...] The improvements in energy production ranged from 81 percent to 660 percent, with an average of about 314 percent more energy."

So, take the lowest number (81%), divide it in half and you STILL have an increase of 40%. I would think such an increase would be fairly significant. But a 660% increase? Naahhhhh......not buying it.

[Saribro]

Right.. so:
- Tiny turbine in free stream
versus
- same Tiny turbine on their setup

So: They added something to an existing turbine to improve its performance.
If that didn't show better numbers it would have been a total failure.

The relevant comparison, however, would have been:
- Tiny turbine on their setup
versus
- Currently cost- and/or total size equivalent "orthodox" setup.

I also find it odd they had to "calculate" the generated power, instead of just measuring it.

[coaster]

If you swapped the incoming airstream for noise waves and the turbine for a sensitive microphone, maybe the coil in the microphone could make a bit of power, 1 volt perhaps?

I was not trying to belittle anyone of average IQ, I myself are such a person too.

I worked on a customers invention, a turbine for placing in tidal streams, axial flow, nylon bearings with several compressor stages.
Water does not compress, the friction of the nylon was very high, they placed the turbine in a 'solent' tidal flat.
Nothing happens, not even half of an revolution, the customer in his frustration placed a firehose at full noise into the device to generate 2 or 3 RPM.

The big ticket is the fusion project (ETA), if they can stop the reaction from breaking down, the world will become like Star Wars with floating vehicles and starships burning energy with abandon and free of care.

[tathan]

Why are wind turbines only 3 (usually) blade? Is it to keep the freestream velocity up which 'drags' the air on the blades along?

Since this 'invention' seems to work by taking lots of slow air and concentrating it into a smaller, faster flow, couldn't the same energy come from the original bigger slow air if there was more efficient collection of it? They aren't (obviously) making energy, they're just accelerating it as a by-product of concentrating it.

[hollus]

Wiki is your friend: http://en.wikipedia.org/wiki/Wind_turbine_design
Three is a good compromise between efficiency and complexity/weight, that contrary to appearances effects most of the incoming air. Even if the blade area is rather small, they extract up to 50% of the wind´s kinetic energy as a) they affect airflow an area larger than the blade and b) they rotate several times faster than the wind (6 to 7 times faster according to that source). Hence it is not a case of the wind pushing the blades, but a case of the blades cutting through the wind at high speed, making them effectively much wider.
The tip speed is not apparent due to the large dimensions of wind turbines. If you haven´t already done it and have the chance, choose the largest turbine in your area and walk right below it. Then look up, and the size, tip speed and energy gathering capacity become apparent all at once.