Liquid cooler powered by compressed air

[BigBang J]

Hey guys, I have an idea here but I don't have all of the science down.

O.K. so I have noticed that if you drain a 15 gallon air compressor tank through the moisture drain port, when most of the air is drained out of the tank there will be ice forming under the port.

I also have a 30 oz. air tank that I pump up to 1000 psi, and when I open the needle valve and let all of the air rush out, there will be condensation forming at the discharge point and is very cold, 40 degreese F or less.

So my sister makes lots of tea which we drink with lunch and supper all the time, but sometimes there isn't enough time for the gallon of tea to get cold before supper. So I want to use the compressed air cooling principle to make an instant tea chiller.

Does anybody have anymore knowledge on this subject and what principles have to be in place in order for this coolin process to occur?

[Crna Legija]

i would try the freezer first

anyway, let me google that for you


dam you drink a lot of tea

[saefroch]

This is a very basic ideal gas relationship, which can also be explained using conservation of energy, but that's neither here nor there. P₁/T₁=P₂/T₂

This is exactly the same principle that your freezer or refrigerator uses to operate, but your freezer does it far more efficiently. A compressor pressurizes a gas which causes an increase in temperature, then cools it to the outside temperature with a fan, so it has a lot less thermal energy than it did before. The substance then passes an expansion valve, which lets it slowly leak out into a chamber at much lower pressure, and upon doing so the expansion chamber is cooled, and air is blown past it to cool the air, which is blown into your freezer or refrigerator. The gas is then sucked out of the expansion chamber by the compressor and reheated from the compression.

I'd just use the freezer. I'm going to throw numbers at this and edit this post later.

Numbers seem to confirm what I suspected. The expanding gas can absorb enough heat to cool the water, but if you ever managed to do it, it'd be a miracle because the expanding gas will absorb heat from the atmosphere and its container far too fast to be of much use.

[Technician1002]

The simple decompression of air for cooling is very inefficient. A vortex tube cooler will be better as it will use less air and works like a heat pump with a hot side and a cold side.

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

[POLAND_SPUD]

A compressor pressurizes a gas which causes an increase in temperature,

Doesn't it just squeeze heat from 10L of air and compress it into 1L (at 10bar)

Now that you have something at higher temperature than ambient it slowly dissipates heat. So when you vent the chamber you get the same process at work - only that this time 10 L of air has the same heat as 1L would normally have under normal conditions[/quote]

[BigBang J]

So you guys don't think that this is such a good idea?

even if I dumped 15 gallons of air through a specially made tea pitcher with copper tubing coiling from bottom to top?

I really am not concerned about efficiency, I just want to know if it would be faster than using the fridge? And was hoping that I could cool a gallon of tea in like 5min.

[Technician1002]

15 gallons of air is not enough to make an ice cube. It is enough to cool the 15 gallons of air to freezing temperature. The problem is the cool will remain with the 15 gallons of cool air.

[BigBang J]

Who said anything about making ice cubes?

I said cool 1 gallon of tea.

[Technician1002]

Try using a blow gun and feeding it into a 1 inch copper tube about a foot long. See how cold the tube will become with your hand on it while draining a 15 gallon air compressor. It will get cool, but it won't take away enough heat to cool a gallon of tea very much.

[Heimo]

I have a better idea for you, if you want to rapidly cool a gallon of tea quickly,
make yourself a large coil of some thin copper tubing (the thinner the better), then submerge the coil in a ice bath, than all you need to do is pass your gallon of tea through the coil and you'll be golden...

[Technician1002]

For beverages that may be acidic, a stainless steel heat exchanger is recommended. This heat exchanger is commonly used in portable soda dispensers.
http://www.beveragefactory.com/draftbee ... xes.shtml.

[Heimo]

For beverages that may be acidic, a stainless steel heat exchanger is recommended.

good point somehow I did not think about that

[BigBang J]

Hmmm yeah thats a pretty good idea but this needs to be ready to use whenever. I can't be keeping a large amount of ice on hand all the time.
I guess I mean it needs to be convenient.

I am looking at building a Ranque Hilsch vortex cooling tube.

Anybody here made one of those??


I have an air grinder that I use a good bit and it gets cold after 1 minute or so of opperation. Enough to condensate.

[Technician1002]

If you are out in the country, what sources of power will you have. Will you have more than just a 15 gallon tank of compressed air?

I personally take a small bar fridge and an inverter to run off the car electrical system while traveling and then use blue ice to maintain the cold while I am there.

Roughing it with a fridge A gel cell and inverter runs the lamp. It is much brighter than a lantern.


Main inverter in the trunk provides a KW of power to start compressors.

[BigBang J]

Yes, I have a 20 gallon tank as well. So 35 gallons of air total.