Tunnel airflow secondary use

[area51branson 0]

Hi All first post here. I'm a paraglider fan . Always wanted to try a tunnel but dont have one anywhere close by
Here is a thought on how to make a tunnel maybe more profitable . Its by making a special room that the intake air for the tunnel is pulled through to generate a gental ,constant breeze of enough speed to kite a paraglider or speed wing in for training or even just for power kites and such to play in as a added adventure to the facility .
I have no idea on the CFM requirements, or room shape that would allow it to happen It would take an expert in airflow . But it seems there might be enough , and if not maybe the tunnels intake flow across this room could be backed up with extra fans in the "kiting" room to get the airflow needed . which is around 5 to 10 mph .
Anyway Like I said , just a thought here , It sure would be fun to have a place to go kite anytime of year no matter the weather ! Anyone have any ideas ?

[chuckakers 370]

Can't even begin to answer your question, but it's an interesting one. Any additional uses for the flowing air would hinder airflow to some point, so certainly that additional requirement would have to be addressed (less efficiency in moving air costs money), but conceptually it sounds like a creative way to use air that is already moving to aid the revenue side of the business model.

Pretty much talking out of my rear-end, but I like it - especially just the kite idea.

Chuck Akers
D-10855
Houston, TX

[area51branson 0]

Hey ! Thanks Chuck .
I dont see where it could hender the air flow unless the wing got away and got sucked into the actual intake grates to the fan room. Like a plastic bag getting sucked into your homes central air return vent grate ,where the filter useually is .
More than likely a netting well ahead if the intake port would prevent that. The air would still have room to go around and not impeed air flow to the tunnel.
Its like a large volume of slow moving air funneled into a small but high speed shaft of air . We're controlling the large volume of air in a focused coradore that speeds the air up slightly then it feeds the fan room.

[chuckakers 370]

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Hey ! Thanks Chuck .
I dont see where it could hender the air flow unless the wing got away and got sucked into the actual intake grates to the fan room. Like a plastic bag getting sucked into your homes central air return vent grate ,where the filter useually is .
More than likely a netting well ahead if the intake port would prevent that. The air would still have room to go around and not impeed air flow to the tunnel.

Not sure that logic works out the way you think. When moving the insane volume of air needed to push a 12-16 foot diameter column at 120 to 160+ mph, darned near anything that disrupts flow becomes a huge factor at any point in the circulation system. These tunnels rely very heavily on efficiency to be profitable, so even a small impact on airflow can make a big difference in the bottom line.

Not saying your idea doesn't have merit. It's just that you have to pay for even small inefficiencies.

Alan Metni of Skyventure could probably answer your question. I would think he knows the numbers inside out and backwards.

Chuck Akers
D-10855
Houston, TX

[area51branson 0]

LOL I bet a tunnel builder is sitting in front of his PC right now slapping his head saying "Why didn't I think of that . Stupid sap he just gave away a million dollar idea,"
Well that may be true , But I have no way to facilitate this idea. And I have a lot more so I'm not too worried . But if your a tunnel builder and like this idea , just remember who you got it from in case you get a sudden attack of guilt. like that type of honesty exists in todays world .

[hokierower 0]

While I think the idea is good, the design seems like a pretty daunting task. In addition to the original structure, the engineer must create an additional room with additional recirculating fans to keep the air traveling. The structure itself has to be pretty big, 20x30 at a minimum for a pilot to get any sort of use out of it, and even that's pretty small. That's 600 sq ft. The SVCO tunnel has 4x350hp turbines which can push air through the existing 120 sq ft. tunnel at 160-170mph. Even at only 20mph, that extra 480 sq. ft. will require some honking turbines to push the "residual air" through the new system. And if you don't have enough and space them out just right you can run into spots where the air flow isn't the same.

With that said, the only time that it would be able to be used would be when the tunnel is not in use by funjumpers as you never know when the flyer(s) will need full power. Full power = no residual air.

Sadly, it just doesn't make sense from a financial point of view. Canopy flight is not a carnival ride that one time participants can jump in and out of without serious risk. No one timers, no income, no ROI.

[area51branson 0]

I was thinking more of ambiant air that surrounds and feeds the tunnel getting sucked in , not pushed in the "kiting room" unless ther were large squirrel cage blowers at about canopy height to help keep the wing inflated..maybe
Valid points on "one timers" Suppose that this was for instruction with ether SD canopy or PG wing.

[NWPoul 1]

It's cool to offer some innovations to the WT design))
Ok, I have some conception too)

P/S Yes in simple conception bodyflyers at second FlyZone could be surprised by airspeed changes caused by flyers in first zone... so
it's more fun)) (or need to more motors installation)

Why drink and drive, if you can smoke and fly?

[likearock 1]

How about just using the airflow to power a generator and create electricity that could then be directly used by the wind tunnel? Cut down on those huge electric bills.

[rehmwa 2]

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How about just using the airflow to power a generator and create electricity that could then be directly used by the wind tunnel? Cut down on those huge electric bills.

you're mocking them aren't you?

any idea that takes energy from the flow requires that energy to be replaced (more power consumption) - it's not 'free' from the system

therefore - 2ndary uses of the airflow would have to be justified by an increase of market and facility usage, because - again - you still have to pull more power for any added usage anywhere in the flow stream

and - any energy usage for something the tunnel is not optimized to (flying something 'else' in the low flow basement area, or power a generator (this one is really funny) we be a less than most efficient use of the facility)

if not already there - one is better off just putting money into marketing and proactive maintenance to allow the tunnel to be fully utilized to the max extent possible - IMHO


dammit - those pesky laws of physics

...
Driving is a one dimensional activity - a monkey can do it - being proud of your driving abilities is like being proud of being able to put on pants

[sxc 0]

"How about just using the airflow to power a generator and create electricity that could then be directly used by the wind tunnel? Cut down on those huge electric bills. "

And while we are at it, we could just create some extra and sell it back to the power company?!!

[beowulf 1]

The way I see it is to turn on a vacuum cleaner and notice that any restriction of the air flow either from the intake or the exhaust will cause the motor to work more. And by causing the motor to work more it is using more electricity and is less efficient. So adding any additional use of the airflow of a wind tunnel will decrease the efficiency and cost more money.

[area51branson 0]

Expanding on your exanple of a shop vac .I made a 1 foot round parachute out of tissue paper and thread and placed it in the hall way where the central AC unit 's return grate is located . The parachute inflated from the air movement down the hall but I did not notice any reduction in airflow or any laboring of the fan . When the parachute was faned out over the intake grate and sucked to it , yes It did have a profound effect .
So if the PG wing is in a big enough hallway where the overall volume of air the tunnel fan needs to function properly is traveling at a slow speed Because the hall way is big enough , there is plenty of volume to still provide unobstructed air flow to the tunnel . The air simply goes around and re combines because it has space and slow enough to do so. Once the wing is up and flying there is even less obstruction .
The return grate on the AC unit and the hallway seems like a good scaled down example for the mass of air movement a tunnel generates on its intake side .

[beowulf 1]

BTW, I think all the new tunnels are recirculating.

[Remster 24]

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BTW, I think all the new tunnels are recirculating.

That I know of, yes.

And don't fool yourself: adding any impediment to the airflow will do 2 things:
- Increase the HP requirements from the motors;
- Increase the turbulence of the airflow around that impediment.

You can address both issues (bigger motors, and more airflow controls and baffles, but that will mean bigger motors too). Both those control measure will increase the cost significantly, including the added cost for the new flight chamber.

Finally, on the option of having the recirc design with a central return and 2 outside chamber: sounds pretty cool. But the mechanics of regulating the airflow to both sound daunting to me.

Remster

[area51branson 0]

Regulating the airflow in the Kite room . The initial building of the kite room could be designed to provide bearly aduiquite kite-able air flow through the room, at the tunnels lowest customer useable setting, then to gain airflow speed moderatly through the room, as the tunnel speed goes up.
Or the room is shaped like a square funnel . Depending on the tunnel speed is where you would position your self in the kite room funnel for the desired wind speed .
Or the majority of air flow is made by the tunnels intake but would need backer fans in the kite room to make up the difference. This would put the intake at the tunnel fan at a positive pressure insuring a consistant air streem in the tunnel
It all depends on The CFM the tunnel moves at any given thrust as to the the size of the kite rooms cross air flow . It may be that the room would be to small to make the needed airflow speed to be of any use .
.
Just thoughts here. I'm certainly not an engineer of fluid dynamics .

[likearock 1]

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How about just using the airflow to power a generator and create electricity that could then be directly used by the wind tunnel? Cut down on those huge electric bills.

you're mocking them aren't you?

any idea that takes energy from the flow requires that energy to be replaced (more power consumption) - it's not 'free' from the system

Agreed - to argue otherwise would allow the possiblity of a "perpetual motion" machine where all our energy problems are solved. I'm not saying that.

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therefore - 2ndary uses of the airflow would have to be justified by an increase of market and facility usage, because - again - you still have to pull more power for any added usage anywhere in the flow stream

Again agree. Clearly the motors will have to draw extra power to be able to do the double duty of power the wind tunnel and the generator at the same time. Just as obviously, the amount of electricity that could be regenerated in this example will necessarily be less that original electricity powering the tunnel motors. However, that's not the important comparison here. The key question is whether or not the difference in power consumption (between having a generator and no generator) is greater or less than the power that is regenerated. That's what would determine whether or not such an idea could be profitable.

I admit I don't know enough physics to give this a deep analysis. But I do know that the consideration of whether or not using an electrical generator in that way could be profitable does not require you to disbelieve any the laws regarding conservation of energy.

[Remster 24]

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The key question is whether or not the difference in power consumption (between having a generator and no generator) is greater or less than the power that is regenerated.

That's the very definition of a perpetual motion machine.

Remster

[likearock 1]

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The key question is whether or not the difference in power consumption (between having a generator and no generator) is greater or less than the power that is regenerated.

That's the very definition of a perpetual motion machine.

Forcing me to dust off my algebra, will you?

Okay, here it is.

Let E = the energy required to power the wind tunnel (without an auxiliary generator)
Let E' = the energy required to power the wind tunnel with the generator.
Let e = the energy created by the generator when it is inserted into the wind stream.

Conservation of energy tells us the following:

e
Violation of the above would be equivalent to allowing for a perpetual motion machine.

As far as I know, it does not tell us that

e
But I could be wrong.

[area51branson 0]

Are the tunnels powered by diesel electric , or just electric ?

[PhreeZone 14]

Just electric. Also the volume of air that you are talking about in recirculated designs has intakes that measure 100 sq feet or larger on each side of the building through a series of louvers and grids to control the temperature of the airflow in the flight chamber. The wind speeds in the flight chamber are 120-170 mph.

I'd suggest looking at how a modern tunnel is really built since it would be far easier just to build you a "kiting room"as a stand alone facility then it would be to tack anything on to a skydiving tunnel in their current designs.

Yesterday is history
And tomorrow is a mystery

Parachutemanuals.com

[chuckakers 370]

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The way I see it is to turn on a vacuum cleaner and notice that any restriction of the air flow either from the intake or the exhaust will cause the motor to work more. And by causing the motor to work more it is using more electricity and is less efficient. So adding any additional use of the airflow of a wind tunnel will decrease the efficiency and cost more money.

And while that's true, the additional revenue from the added activity could make up for those additional costs. Much like the tunnel itself, which cost big bucks to operate, yet operate (presumably) at a profit.

Chuck Akers
D-10855
Houston, TX

[beowulf 1]

I don't think it would make up for additional costs.

I see it like building a big fan to power a wind turbine. It just isn't going to work out as money making deal. Unless you charge more for the tunnel time to cover the inefficiency of generating power.

[chuckakers 370]

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I don't think it would make up for additional costs.

I see it like building a big fan to power a wind turbine. It just isn't going to work out as money making deal. Unless you charge more for the tunnel time to cover the inefficiency of generating power.

You're welcome to your opinion but without knowing what the costs and potential revenues would be, I don't think it can be said that it couldn't work.

It's more a matter of whether or not enough volume of paying customers could be attracted to use the facilty for a fee - just like skydivers use the vertical tunnel for flying and they make money.

Are you saying that a stand-alone facility for kite flting or soaring couldn't make profit either? Pretty sure there were people that told Alan Menti he couldn't make money with faster, more expensive tunnels - and now they are all over the world.

Chuck Akers
D-10855
Houston, TX

[sxc 0]

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The key question is whether or not the difference in power consumption (between having a generator and no generator) is greater or less than the power that is regenerated.

This is the basis of the second law of thermpdynamics.
The first law, which is the conservation of energy, says we cannot create energy, only convert it from one form to another.
The second law tells us that we cannot ever convert from one form to another with 100% efficiency. So the power regenerated will always be less than the difference in power consumption.