Use of Vortex tubes

[ruble3]

I was doing research into 'cooling' systems when I saw vortex tubes- although most of them are quite small, I was wondering if they have any applications for using them to cool a room? I have an abundance of compressed air-would rather not use standard air conditioners(as in a house)-
(drop in temperature not important right now, as any drop is beneficial)- I can size a tube(s) later if they would work- I can post room sizes, air supply etc later; right now just looking for comments

 

[MintJulep]

Technically there is no reason why you couldn't.

From a practical standpoint compressed air is pretty much the most expensive untility available.

 

[IRstuff]

That really wouldn't be very efficient in any case, since a sizable amount of air must go out the hot side, which means that you'll need to plumb that to an outside vent.

Additionally, you'll still need an air handler, since the tubes will not get much air mixing to efficiently cool large volumes.

TTFN

 

[EdStainless]

They are very inefficent, I even hate using them in electrical enclosures. Though they are great for spot cooling.
If you have that much free air available you would be better off running it through a turboexpander and using the shaft work to run a compressor.

= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be managed.

http://www.trenttube.com/Trent/tech_form.htm

 

[zdas04]

I recently saw a separator with a "top hat" that had a really narrow annulus and the temperature drop across the vessel was 12F (the designer had inadvertantly created a Ranke-Hilsche Vortex Tube, the hot gas was absorbed into the water at the bottom of the vessel which increased in temp about 2F). This vessel was moving 3 million CFM of natual gas, so these beasts seem to be able to be pretty scaleable.

They aren't really very effecient, but if you can find a synergistic way to take advantage of a dT that is happening anyway then a waste-heat stream can become a valueable resource - that is just good engineering.

David Simpson, PE
MuleShoe Engineering

http://www.muleshoe-eng.com

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

The Plural of "anecdote" is not "data"

 

[ruble3]

Thanks for the comments- I may want to sacrifice efficiency
for end result, which is cooling a hot & humid working environment ( we're looking for a place where they can go to 'cool' down if they becomes heat stressed)- if I could find a use for the hot air stream it would be even better but there are no practical uses for hot water underground -I looked at the turboexpander but don't think the cost would be justified ( may be able to use them to generate power since the other big issue here is a lack of electric power)
The research never ends!

 

[IRstuff]

Your comments re electrical power make no sense. You've got some sort of power source to generate the compressed air. That same power source could directly drive air conditioning compressors and get more cold air than with the vortex tubes.

TTFN

 

[StoneCold]

Ruble3
I see that you are in mining. I thought that they pumped chilled water down the shaft for just these types of things. Cold air radiators, cold vests for the workers etc. You can get the vests that incorporate the cooling effect right into the vest and run on air. That would be smarter than trying to cool the whole room with air, besides, as mentioned above you have to push the heat somewhere else it does not just go away.

Just my thoughts

StoneCold

 

[ruble3]

StoneCold: you're absolutely right, for 'modern' mines- ours is upwards of 50 yrs old & adding something like that is too burdensome at this point- we will be operating out of a new mine soon, which will incorporate either chillers or a more elaborate ventilation scheme- I was just trying to do something inexpensively(before the move) when I saw the tubes-
(IR Stuff- I was being facetious when I said about using compressed air to run generator-my compressed air plant is 6000+ feet from the rooms I'm trying to cool)-since the rooms are supplied with a compressed air line (normally closed) I thought I could mount the tube out in the drift & plumb the cold air into the room- I think for now the best option is cracking the air line, reduce the humidity & see what happens
Thanks

 

[jrhols]

While I agree on efficiency issues except powered vortexes are more efficient at heating than cooling due to the friction of the air flow, there is such a thing as you asked about. A passive room cooling system was conceived of by the famous designer Buckminster Fuller. He found that by placing a small hole at the top of a dome shaped structure or TeePee or Yurt, that the inflow of outside air stricking the inside trapped hot air caused that inflowing air stream to expand. As you may be aware from gas laws and safety standards, this effect is dramatic and is a cooling source for the room. Perhaps I should say this is more a lost civilizaton's technology being re-discovered than a new principle in science. The effect is sensitive to hole size, so you may not have a completely passive system, but the American Indians controlled this with a movable flap, which doubles as movable insulation or vice versa depending on your point of view.

 

[chicopee]

Why not release this "abundant" compressed air into the environment that you want to cool. Compressed air released to atmospheric pressure is relatively colder than what it is in its compressed state. You can use the gas laws to estimated the temperature of this colder air release at its nozzle; and than you can estimate the bulk air temperature of this "mixture". Caution-Above thinking not recommended with contaminated compressed air.

 

[mtnengr]

Vortex tubes have been used for refrigeration. For small volumes, the process seems to work OK. When trying to apply this principle to a larger installation, be sure to examine the Second Law of Thermodynamics. I have seen and tested components that use the vortex principle in a piping system. Very large efficiences were claimed, but did not materialize. The Second Law of Thermodynamics still holds!

 

[zdas04]

Actually, Ranke-Hilsche Vortex Tubes only appear to violate the 2nd law of thermodynamics.

I recently read a theory that claims that the continuity equation requires conservation of angular momentum. Since the Vortex tube has a nearly constant angular velocity (between the inner and outer streams) and a smaller moment on the inner stream it is reasonable for the energy "imbalance" to be made up in heat passing to the higher-momentum stream.

I'm not 100% confident that this theory adequately explains all of the components of the various flow streams, but it is certainly worth further study. I just wasn't buying the "magic" explaination.

I've never heard any claim these widgets are very effecient as a heater/cooler - the niches where they are working well are all things that lack economies of scale for more effecient methods to be worth the cost of installation.

I've looked at a couple of applications recently (details are restricted by a confidentiality agreement) that may be commercial for some very specific and focused niches.

David Simpson, PE
MuleShoe Engineering

http://www.muleshoe-eng.com

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

The Plural of "anecdote" is not "data"

 

[hacksaw]

one simplified explanation is an adiabatic expansion to a low velocity condition at the fluid pick-off in the vortex chamber. this is just the opposite what occurs in the usual expansion process where the velocity reduction (stagnation) reheats the gas.

 

[zdas04]

Most of the research-oriented papers I've read on this lately have talked about angular velocities in the "millions of rpm" range, quite a distance from "low velocity conditions".

David

 

[hacksaw]

even at that angular velocity, at the center of the vortex chamber (cold stream pick-off) the linear velocity is small.

 

[dcasto]

go here to see a real application of this technology. They even explain how it doesn't break the second law. I've used this technolgy to cool an purge our electrical cabinets using the little units used to cool sand blasting hoods.

http://www.twisterbv.com/