New wind tech, grain of salt needed

[seifrob]

Hi,

today browsing lead me here: SheerWind. Although I am friend of reasonable alternative energy, this simply seems to be too good to be true, so skepticism is welcome. What do you think? Any experience?

[ChazInMT]

Looks cool, I've often wondered myself why you need a huge tower & blades to generate the power and thought some sorta ducted wind concentrator could be effective. I question their passive collection system, it seems they could implement a larger "Wind Scoop" that rotates to face the wind which would make it more effective for a given amount of building materials.

[Ryland]

Air density is pretty constant, so if you take wind speed and collector size you can figure out the maximum power output, power output is cubed as speed increases at the collector, wind speed increases as you increase height.

This device has low height so low wind speed, it also has a small collector area for the amount of materials that are in it.

[jakobnev]

No why would wind want go down that silly tube when it could go around it more easily?

[niky]

They do have field data (still grain-of-salt) that shows improved collection. I'm of the mind this can work if done properly.

Reminds me of this:


In both cases, you're asking the wind to squeeze itself into a tighter space rather than going around. If the taper is right, it will. And it will gain speed as it goes through, allowing you to generate more power from smaller turbines.

[Ryland]

No why would wind want go down that silly tube when it could go around it more easily?

Some of the wind is always going to go around, same with a regular wind turbine prop, it all depends on how much resistance there is, that is why there is a finite about of energy that you can collect out of the wind, if you could collect 100% of the energy then you could have wind go in and still air exit... and that doesn't work.

The collector is the part up in the air, on a regular wind turbine the collector is the prop/propeller, on this one it's the scoop, if you were to put a funnel around a regular wind turbine prop then the opening of that funnel is the collector size, those turbines between two buildings use the buildings to increase the collector size, the draw back of course is that they impose their own limitations, like not being able to turn with the winds changing direction.

There have been a lot of sketchy wind companies that have "new" ideas that skew their facts to draw in investors.

[freebeard]

Originally Posted by jakobnev

No why would wind want go down that silly tube when it could go around it more easily?

It appears to consist of 8 exponential horns, which couple well with the ambient air, in a cluster. Once the mass of air enters the orifice it is (IMHO) easier to change the direction than it's speed. Only two or three openings will be accepting incoming air. The others will be trying to revert it.

They drop the ball there though—the horns should spiral around each other so the mass of air is moving counter-clockwise (in the Northern hemisphere, clockwise in the Southern) as it falls. This would create a Gravity Vortex. They're leaving free energy on the table.

The elbow is just stupid. If they made the tower taller instead, it would improve the performance. The turbine should have a centrifugal exhaust, or at the very least a bellmouth.

This is all very easy to see from the comfort of my armchair.

Originally Posted by ChazInMT

I question their passive collection system, it seems they could implement a larger "Wind Scoop" that rotates to face the wind which would make it more effective for a given amount of building materials.

Ya know those ball-shaped rotating ventilators you see on the top of warehouses?

A big one of those, only mounted solid so it won't turn. An exhaust elbow on the top that weathervanes so it always points downwind. A vertical shaft in the middle with a bunch of paddle wheels on it. Voila.

[redneck]

Watch.


http://www.youtube.com/watch?feature...&v=m7xGGt-8EnE

10 mph wind is caught in the collector, accelerates to 40 mph at the Venturi then exhausted at 15 mph.

So then a 60 mph wind accelerates to 240 mph and is exhausted at 90 mph ?

Doesn't sound right to me.

When a conventional wind mill exceeds its recommended wind speed, they turn out of the wind path to prevent over speeding and damage.

How is that controlled in this design ?

Variable pitch blades ?

What sucks about things like this is that the amount of information
released is vague at best.




>

[NeilBlanchard]

It looks like a scam to me. But that doesn't mean that actual wind turbines are not totally legit.

[Ryland]

With this design the exiting air is being dumped in to an area with low wind speed so it's meeting resistance there, the back side of the collector that is not facing the wind is seeing a strong negative pressure, most likely sucking a large amount of that moving air back up and out and as redneck pointed out, what do you do when you have high wind speeds?
What about snow, freezing rain, hail, fall leafs?

It's a bad design that looks like the kind of thing a middle school kids came up with.