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area51branson

Tunnel airflow secondary use

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I like you Chuck, but you make a lot of assumptions. I never said anything regarding kite flying or soaring. Let me make myself clear. I don't think that adding a wind turbine to a wind tunnel will be efficient enough to over come the added costs in operating the wind tunnel. So to compensate for the inefficiency the consumer would have to pay more per hour of wind tunnel time. In the end it would be easier to just raise prices rather then go through the trouble of installing wind turbines to generate power.

As for the kite flying or soaring well that's a whole new topic that would require research. I don't know if there is a demand for such a product and if so how much of a demand. Is it worth building? I don't know.

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Since we're having some math fun! (and I may be completely off too, but lets see where this leads us... )
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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 < E < 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 < E'-E


I have no clue what you're trying to show here.. Sorry man...

Of course e < E-E' . There are so much inefficiencies in such a system that the energy created will be much smaller than the energy powering the system. You're looking at least 10% loss at the motor itself. Then intake/exhast turbulance will probably be another 20% best case.
Remster

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I was hoping for a use of the by product of the tunnel operations air movement . Certainly a wind mill generator is going to take a lot of force / drag to make electricity of any KW's to offset the cost of operation. And I can see that as messing up the airflow ether at the intake or exhaust .
Where as a Kite room would have little effect if designed properly ,, and only if indeed the airflow is enough in mass volume to do so .
A 100' square ft intake is small , a little over 3 sheets of plywood. Anyone know the speed of air at the intake? And Do any of you get your wing out and kite them on a good breezy day? If so what is your reason for doing so ?
I know us PG guys do so as often as we can to keep our skills up, and today would be a good day for it here , but i have to be at work in a little bit . dang it ! :S

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

e < E'-E



of course it is - any change of form or energy has less than 100% efficiency

you'd be better off just plugging your radio into the outlet rather than plugging a generator into an outlet and then plugging your radio into a generator

alternate uses would be most efficiently supplied by custom facilities for that use

or else, the 2ndary user will be paying much more for the inefficient use of a system not designed for it

...
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

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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 .



silly - it would still increase the power demand - nothing is free

...
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

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I like you Chuck, but you make a lot of assumptions. I never said anything regarding kite flying or soaring. Let me make myself clear. I don't think that adding a wind turbine to a wind tunnel will be efficient enough to over come the added costs in operating the wind tunnel. So to compensate for the inefficiency the consumer would have to pay more per hour of wind tunnel time. In the end it would be easier to just raise prices rather then go through the trouble of installing wind turbines to generate power.

As for the kite flying or soaring well that's a whole new topic that would require research. I don't know if there is a demand for such a product and if so how much of a demand. Is it worth building? I don't know.



We were having 2 different conversations. I was referring to the idea of adding an area that would use existing (or beefed up) air flow to add kiting or soaring to an existing tunnel operation. That's what the OP was asking about.

I agree with you on you opinion on the turbines. The tunnels are about as tweaked out as they can get with current technology anyway. Metni has spent untold dollars on the engineering to get them where they are, so I'm sure if there was a more efficient way to do it he would be headed that direction.

I'm sure we will eventually have better/cheaper ways to push volumes of air, and when we do we will see it in action.
Chuck Akers
D-10855
Houston, TX

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Since we're having some math fun! (and I may be completely off too, but lets see where this leads us... )

Quote

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 < E < 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 < E'-E


I have no clue what you're trying to show here.. Sorry man...

Of course e < E-E' . There are so much inefficiencies in such a system that the energy created will be much smaller than the energy powering the system.



Yes, but the energy "powering the system" is E' (not E'-E). So all you're really saying with your statement is that e < E', which as I said before is not the relevant question.

Quote


You're looking at least 10% loss at the motor itself. Then intake/exhast turbulance will probably be another 20% best case.



Let's go with that then. Say it takes 500 kWh per day to power a wind tunnel. By your calculation, the electricity that could be produced from a generator inserted into that wind would take a hit of 30%, bring it to 350 kWh. So the question is now, how much additional electricity would the wind tunnel require to run that generator?

It's conceivable (at least to me) that it could require something less than an additional 350 kWh to keep the generator going. For instance, if it took an extra 200 kWh, that would bring bring the total (E') to 700 kWh. Is it so difficult to believe that air infused with 700 kWh of energy can be converted to 350 kWh? And if that were the case, you're looking at a net gain of 150 kWh per day.

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No -

e is MUCH less than E' - E

You have to power the wind tunnel
You also have to power the wind generator - you don't get free or even discounted 'leftovers' from the other.

It's silly to burn electricity to power another power generator.

your example with made up numbers to show the concept

500 kW to power the tunnel
700 kW to power the tunnel plus your generator

the generator output will absolutely produce MUCH less than 200 kW

it's a losing proposition - you are better off just powering your 200 kW air dryer from just an outlet in the building

put your wind mill outside where the wind actually is free

...
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

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This "Kite Room" sounds retarded as a tard.
Why don't you go outside for that???
Who in right mind would want to fly their kite or PG wing in a enclosed room, when there is fresh breeze outside with great fucking view.

I can power kite with less than 5 mph wind. Get some skill and bigger wing.
Bernie Sanders for President 2016

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>It's conceivable (at least to me) that it could require something less than an
>additional 350 kWh to keep the generator going.

Nope. It will ALWAYS require more.

Now, if you really want to reduce power requirements, just make the air passages in the return area bigger. Lower resistance = less power needed.

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BTW if you really want to run a tunnel for free (or even make some power on the side) there's always the solar updraft tower:

http://en.wikipedia.org/wiki/Solar_updraft_tower

Airspeeds are typically 30-40mph but put in a venturi for a flight chamber and you could get speeds in the 120mph range, albeit with a severe loss in generation capacity.

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BTW if you really want to run a tunnel for free (or even make some power on the side) there's always the solar updraft tower:

http://en.wikipedia.org/wiki/Solar_updraft_tower

Airspeeds are typically 30-40mph but put in a venturi for a flight chamber and you could get speeds in the 120mph range, albeit with a severe loss in generation capacity.



My god, a green wind tunnel - that would be something!

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BTW if you really want to run a tunnel for free (or even make some power on the side) there's always the solar updraft tower:

http://en.wikipedia.org/wiki/Solar_updraft_tower

Airspeeds are typically 30-40mph but put in a venturi for a flight chamber and you could get speeds in the 120mph range, albeit with a severe loss in generation capacity.



My god, a green wind tunnel - that would be something!


And if you think the Eloy tunnel gets hot in summer... ;)
Remster

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This "Kite Room" sounds retarded as a tard.
Why don't you go outside for that???
Who in right mind would want to fly their kite or PG wing in a enclosed room, when there is fresh breeze outside with great fucking view.
I can power kite with less than 5 mph wind. Get some skill and bigger wing.


Think bigger man . Out side is grate , WHEN its good out . cold wet , storms, Heat, TIME in general! . its all right there day or night . If it were close enough I'de use it ...alot .

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It's conceivable (at least to me) that it could require something less than an additional 350 kWh to keep the generator going. For instance, if it took an extra 200 kWh, that would bring bring the total (E') to 700 kWh. Is it so difficult to believe that air infused with 700 kWh of energy can be converted to 350 kWh? And if that were the case, you're looking at a net gain of 150 kWh per day.



If it really did work that way our energy problems would be a thing of the past.

Assuming that you could convert one form of energy into another at 100% efficiency, adding a turbine that generates 350KWh (removes 350 KW per hour from a perfectly closed system), you would need to add 350KWh more into the system in order to keep the flow rate constant.

Since we're not talking theoretical physics and perfect systems, but instead talking real life, you cannot convert energy at 100% efficiency. The best wind turbine cannot achieve more than 59% efficiency, and more energy will be lost converting the mechanical energy of the turbine's rotation to electrical energy, some portion of which is lost to heat due to resistance. You would be lucky if a turbine generates 35% electrical energy of the energy it extracts from the air flow.

So, if you generate 350KWh from a closed system, you would need to add 1000KWh into the system in order to keep the flow rate constant.

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