Cooling My Beer With Liquid Co2?

polarbear

5th May 2009 - 04:34 PM

Hi,

I want to build a beer cooler using liquid co2.
It will be a system where the beer has to cool down while drafting.
This meaning that I need a explosive cooling during something like 10 seconds.
I want to do this by a heat exchanger element that cools down instantly when opening the beervalve and the CO2 valve simultane.
The CO2 will change state and decompress in the cooling element and then will be released free when leaving the cooling element.
The problem now is that I can not calculate or even have a indication of the amount of CO2 I need for this cooling process,there the temperature of the bottle CO2 and the beer is not fixed,the rendement of heat transfer in the cooling element is unknown.

Please help me I am searching the internet for days and noooo progress.

--------------------

Ron

5th May 2009 - 05:44 PM

Hi Polar Bear,
Here's a link for paintballers, but the pressure vs. temp diagram might help you.
I, personally, would use something like a coil in dry ice (CO2 is much easier to work with solid!), but, as long as you're safe, you should learn alot trying it your way.
Good luck,
Ron

http://www.warpig.com/paintball/technical/...2dynamics.shtml

polarbear

5th May 2009 - 06:10 PM

Thanks Ron

Interesting table,but I am looking more for a calculation.
Something like if you decompress 100 grams of liquid co2 at a starting temperature of 25°C in a cooling element it will free ....Kj of energy that can be transferred to the liquid.And then I mean using the complete decompression from the gas till 1atm.

At the moment I am thinking to purchase some equipment and to do some tests to find out the cooling capacity for my purpose.

Will cost me money,but calculations are not my thing

Trippy

5th May 2009 - 09:37 PM

Enthalpy of Fusion
Matheson Gas Data Book
R-744 Refrigerent (Carbon Dioxide)

buttershug

6th May 2009 - 04:49 PM

Don't do this a lot in the basement.

Remember if you are ever trapped in a sealed bank vault, you won't run out of oxygen.

The CO2 concentration will kill you first.

H2O

6th May 2009 - 07:19 PM

Maximizing surface area exposure should help speed up the process. So instead of a single pipe like spout for the beer to come out, use multiple thinner straw like tubes that converge into one at the nozzle. You can then run the tiny tubes through an ice block. Provided the ice surrounds each individual tube and that each tube is made of a material that has a high thermal conductivity (I think that is the correct phrase) but won't poison the beer then it should cool down quick and still poor the same as long as the total cross section areas of each tube combined equals the cross section area of the nozzle.

buttershug

6th May 2009 - 08:21 PM

DOH!!!!

No one has pointed out that CO2 is not a liquid at normal air pressure.
It goes straight from solid to gas. Which is why it's called "dry ice".

Edit and if the OP knew that, getting liquid CO2 would have to be in a pressurized container and that might not be as readily available as dry ice.

AlexG

6th May 2009 - 09:15 PM

Kegs of beer usually have pressurized CO2 gas injected into them. That's where the head on draft beer comes from. Bottled beer has the CO2 from the frementation process, but kegs are flat.

Trippy

6th May 2009 - 09:42 PM

QUOTE (buttershug+May 7 2009, 08:21 AM)

For my part it was assumed knowledge (i was assuming the OP already knew that) - and it's implied in two of the sources I linked to :3.

polarbear

7th May 2009 - 09:27 AM

Hi again,

I am still working on the cooling element.
The cooling element will have multiple chambers increasing in volume.
Each chamber is connected by a very small hole.
The liquid CO2 (from a high pressure container)will be injected in the first chamber and evaporate,cooling the element/beer down.
Then the other chambers will do a controlled decompression from the gas to 1atm and will be released free.
I want to use the max cooling capacity of the gas using also the energy of decompression to cool down the beer.
There will be also a reducer that gives counter pressure when the cooling elements gets too cold.
So opening the draft handle will open the CO2 valve,will give a flow of liquid CO2 and then when appropriate temperature reached will the flow be reduces.

This to explain that I do not want to use dry ice.
I want to connect a portable system to a high pressure container liquid CO2(need this one any way for the CO2 in the beer),connect a huge keg of beer and hopla
drinking ice-cold beers in the middle of nowhere without a power source or waiting ages before the cooling equipment is ready for use.
If the pressure at injection-point can stay above 6bars and the temperature not below -60° it will work ;-)

hallelujah

Chromodynamix

30th May 2009 - 05:24 AM

I have worked with dry ice and can advise 1 kg of dry ice has the cooling capacity of 2 kg of ordinary ice. Don't know if this helps, but at the bottom of this page are some properties of CO2 which will enable you to do some calculations.

The complicatig factor here is that the beer will freeze round the cooling exchanger and insulate it from the beer, so the beer must circulate at high velocity to prevent this.

http://www.uigi.com/carbondioxide.html

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