...making Linux just a little more fun!
Mercedes-Lopez, Samuel CTR USA IMCOM [samuel.mercedeslopez at us.army.mil]
Hello Answer Guy
I was wondering if it is possible to cool a small amount of water for drinking purpose using a small cilinder of liquid fill nitrogen (by letting the water around the cilinder) is this possible and how long will the water remain cool?
Thanks
Sam
Classification: UNCLASSIFIED
Caveats: NONE
Ben Okopnik [ben at linuxgazette.net]
On Tue, Mar 18, 2008 at 10:39:37AM -0400, Mercedes-Lopez, Samuel CTR USA IMCOM wrote:
> Classification: UNCLASSIFIED > Caveats: NONEAww, too bad. I'd have put on my James Bond trenchcoat and armed myself with all kinds of paraphernalia from Spies'R'Us if it was classified...
> Hello Answer Guy > > I was wondering if it is possible to cool a small amount of water for > drinking purpose using a small cilinder of liquid fill nitrogen (by > letting the water around the cilinder) is this possible and how long will > the water remain cool?
Woo-hoo! Rhubarb warning!
http://linuxgazette.net/issue67/lg_backpage67.html#wacko
In classic TAG fashion, however, I'm going to try to answer your question... for whatever that's worth. Probably not much, since my years of using LN2 (radar-absorptive foam dipped in the stuff makes a dandy black-body radar target) are long behind me - but what the heck.
Cooling water for drinking purposes by dipping the LN2 cylinder in it suffers from a number of problems - and no benefits that I can think of. Problems, right off the top:
1) Your temperature control options range from extremely crude (immersing more or less of the cylinder in the water) to disproportionately complex and expensive (finding a way to vary the amount of insulation around the dewar containing the LN2.)
2) Replenishing the stuff, unless you work for a supplier and are doing it on the premises, or own an LN2 generator, is going to be A Very Large Hassle.
3) Essentially, you're relying on the imperfections in the insulating process - something that, by definition, is not controllable in a reasonable fashion - for your heat sink. This is somewhat like trying to evaporate gasoline by holding a match "just far enough away" from it; not the most brilliant method ever invented.
4) Since you appear to be quite unfamiliar with the properties of this stuff, I suggest that you run away from it very, very quickly. In fact, emigrating to another country, changing your name, and getting some plastic surgery would be safest. And even then, you should request police protection. [1]
Those are pretty large problems. The thing that makes it all really silly, though, is - why would you bother? There are plenty of good, simple methods (e.g., a Peltier junction immediately comes to mind; a small pump cycling, say, alcohol through an expansion valve - if you're mechanically minded - is another possibility) available. This seems like going the long, long way around the barn.
[1] It's not as bad as chlorine trifluoride - that shit sets sand and asbestos on fire - but screwing around with LN2 while ignorant of its properties is an excellent precursor to autoDarwination.
-- * Ben Okopnik * Editor-in-Chief, Linux Gazette * http://LinuxGazette.NET *
Karl-Heinz Herrmann [kh1 at khherrmann.de]
Can't see the Linux connection here....
On Tue, 18 Mar 2008 10:39:37 -0400 "Mercedes-Lopez, Samuel CTR USA IMCOM" <[email protected]> wrote:
> I was wondering if it is possible to cool a small amount of water for > drinking purpose using a small cilinder of liquid fill nitrogen (by
sure. If "cooling" includes deep freezing its trivial.
> letting the water around the cilinder) is this possible and how long > will the water remain cool?
as long as it take for the nitrogen to evaporate and the water to thaw and then get to your preferred drinking temperature.
See http://en.wikipedia.org/wiki/Heat_capacity#Heat_capacity and http://en.wikipedia.org/wiki/Evaporation for details
On the other hand -- if you need funny idea what to do together with your army friends with LN2 -- try: http://www.physik.uni-augsburg.de/~ubws/nitrogen.html
My favorite by far is the (almost) instant ice cream. No fussing around with crushed ice, salt and long stirring.... Just pour the LN2 in, stir with a long wooden spoon, add a little more -- emjoy perfectly tempered ice cream.
Maybe don't copy this guy: http://www.darwinawards.com/personal/personal2000-25.html
K.-H.
Kat Tanaka Okopnik [kat at linuxgazette.net]
On Tue, Mar 18, 2008 at 09:19:53PM +0100, Karl-Heinz Herrmann wrote:
> Can't see the Linux connection here....
It's cuz Linux is supa-cool, man!
> On the other hand -- if you need funny idea what to do together with > your army friends with LN2 -- try: > http://www.physik.uni-augsburg.de/~ubws/nitrogen.html > > My favorite by far is the (almost) instant ice cream. No fussing around > with crushed ice, salt and long stirring.... Just pour the LN2 in, stir > with a long wooden spoon, add a little more -- emjoy perfectly tempered > ice cream.
Back when I lived with a rocket scientist, LN2 ice cream became a standard stunt at our house parties and spacegeek events. Compared to making ice cream using more traditional methods, (aside from the techical expertise to safely handle LN2), making LN2 ice cream is dead simple. No worrying about whether there's too much alcohol in the mixture to freeze, for instance.
I got really creative with flavors as a result. Bananas Foster frozen yogurt, lemon blueberry, a Persian spice blend usually used for savories (baharat, also known as advieh). . .
> Maybe don't copy this guy: > http://www.darwinawards.com/personal/personal2000-25.html
Yikes!
-- Kat Tanaka Okopnik Linux Gazette Mailbag Editor [email protected]
Karl-Heinz Herrmann [kh1 at khherrmann.de]
On Tue, 18 Mar 2008 15:18:00 -0700 Kat Tanaka Okopnik <[email protected]> wrote:
> I got really creative with flavors as a result. Bananas Foster frozen > yogurt, lemon blueberry, a Persian spice blend usually used for > savories (baharat, also known as advieh). . .
Hm.... is that "ready made" stuff then frozen or did you get fruit ice nice and creamy? I tried a few old recipes from a grandmothers cook book which has ice cream version -- but most are based on egg, cream, vanilla, chocolate,..
When I tried to improvise something more "fruity" less/no cream it did not stay creamy, even shock frosted like this. Developed not that little ice crystals.... Any trick to avoid that? cream after all? alcohol? Or do I have to get close to somebody from the Italian Mafia for real good ice recipes?
K.-h.
Kat Tanaka Okopnik [kat at linuxgazette.net]
On Tue, Mar 18, 2008 at 11:57:49PM +0100, Karl-Heinz Herrmann wrote:
> On Tue, 18 Mar 2008 15:18:00 -0700 > Kat Tanaka Okopnik <[email protected]> wrote: > > I got really creative with flavors as a result. Bananas Foster frozen > > yogurt, lemon blueberry, a Persian spice blend usually used for > > savories (baharat, also known as advieh). . . > > Hm.... is that "ready made" stuff then frozen or did you get fruit ice > nice and creamy? I tried a few old recipes from a grandmothers cook > book which has ice cream version -- but most are based on egg, cream, > vanilla, chocolate,..
There are two basic "ice cream" recipe styles. A milk and cream (usually uncooked) base, and one that requires a cooked custard. (There are other frozen desserts with different starting points, but I'm not going to get into that here.)
I made my ice creams "from scratch", except where I used pre-made yogurt. As I recall, the lemon blueberry was actually a frozen yogurt made with lemon-flavored yogurt.
> When I tried to improvise something more "fruity" less/no cream it did > not stay creamy, even shock frosted like this. Developed not that > little ice crystals.... Any trick to avoid that? cream after all? > alcohol? Or do I have to get close to somebody from the Italian Mafia > for real good ice recipes?
Recipes involving just fruit, without any milkfat, require something like eggwhites to provide creaminess and stability. I've never tried making a LN2 sorbet.
I found that the microcrystallization from the quick freezing meant that standard ice cream recipes tasted oily, and so my basic starting point was usually equal amounts of half-and-half[1] with heavy cream[2]. Wikipedia notes:
"Making ice cream with liquid nitrogen has advantages over conventional freezing. Due to the rapid freezing, the crystal grains are smaller, giving the ice cream a creamier texture, and allowing one to get the same texture by using less milkfat. However, such ice crystals will grow very quickly via the processes of recrystallization thus obviating the original benefits unless steps are taken to inhibit ice crystal growth."
This is my experience as well. LN2 ice cream is best shortly after it's made.
The best strawberry ice cream I ever made was by simply macerating[4] good sliced strawberries in some sugar, and then mixing the resulting fruit slurry into my basic LN2 ice cream base. I expect that other fruit would work as well. You really do need to add enough sugar or the fruit will end up like rocks. It's also best to slice the fruit rather small.
[1] 12.5% butterfat cream, known as "half cream" in the U.K.
[2] 36% butterfat cream. This is very difficult to find in the U.S. without carrageenan added in. I dislike that version, as it makes LN2 ice cream have a slimy mouthfeel.[5]
[3] http://en.wikipedia.org/wiki/Ice_cream#Using_liquid_nitrogen
[4] Oddly, there are multiple definitions for "macerate".[6] While Ben and I were discussing this, he found this astonishing [ab]use of the word: http://windupstories.com/2007/12/10/logorrhea-macerate/
[5] Yes, Ben - sometimes even I find "slimy" to be an undesirable food characteristic.
[6] I suppose you might want to know what the definitions of "macerate" are. http://en.wikipedia.org/wiki/Maceration
-- Kat Tanaka Okopnik Linux Gazette Mailbag Editor [email protected]
Ben Okopnik [ben at linuxgazette.net]
On Tue, Mar 18, 2008 at 05:44:41PM -0700, Kat wrote:
> > [4] Oddly, there are multiple definitions for "macerate".[6] While Ben > and I were discussing this, he found this astonishing [ab]use of the > word: http://windupstories.com/2007/12/10/logorrhea-macerate/
Amusingly, I only knew the one (chopping/crushing, as in the action of a macerator) while Kat knew the other (the culinary version, related to soaking.) Completely unsurprising.
> [5] Yes, Ben - sometimes even I find "slimy" to be an undesirable food > characteristic.
Ah - a subtle (ahem!) reference to Kat's natto fetish. This is stuff
that really separates the Japanese from the non-Japanese... as well as
most of the other Japanese. 
I have a strong feeling that it's
intended to terrify us round-eyes - and it is mostly successful.
From the "Steve, Don't Eat It!" archives: http://www.thesneeze.com/mt-archives/000169.php
(Yes, I've tried the stuff - repeatedly. But, y'know, if I don't amuse
myself at her expense once in a while, she loses that certain... edge.
-- * Ben Okopnik * Editor-in-Chief, Linux Gazette * http://LinuxGazette.NET *
Kat Tanaka Okopnik [kat at linuxgazette.net]
On Tue, Mar 18, 2008 at 09:20:18PM -0400, Benjamin A. Okopnik wrote:
> On Tue, Mar 18, 2008 at 05:44:41PM -0700, Kat wrote: > > > > [4] Oddly, there are multiple definitions for "macerate".[6] While Ben > > and I were discussing this, he found this astonishing [ab]use of the > > word: http://windupstories.com/2007/12/10/logorrhea-macerate/ > > Amusingly, I only knew the one (chopping/crushing, as in the action of a > macerator) while Kat knew the other (the culinary version, related to > soaking.) Completely unsurprising.
I was mostly shocked that you didn't know the culinary definition, Ben.
> > [5] Yes, Ben - sometimes even I find "slimy" to be an undesirable food > > characteristic. > > Ah - a subtle (ahem!) reference to Kat's natto fetish. This is stuff
It is not a fetish! I function okay without it. I just prefer not to.
> that really separates the Japanese from the non-Japanese... as well as > most of the other Japanese.
I must admit that it's a Kanto (eastern Honshu) delicacy, and that my Kobe-born uncle, on first encountering it, tried to send it back. "I'm sorry, there's something wrong with my breakfast. I think the soybeans are rotten; they've got thready bits oozing out!"
> I have a strong feeling that it's > intended to terrify us round-eyes - and it is mostly successful. > > >From the "Steve, Don't Eat It!" archives: > http://www.thesneeze.com/mt-archives/000169.php
Oh, stop. Gross exaggeration, as shown in this other "Steve, Don't Eat It!" entry: http://www.thesneeze.com/mt-archives/000142.php (Breastmilk)
A little more balance, please: http://en.wikipedia.org/wiki/Natto
> (Yes, I've tried the stuff - repeatedly.
And enjoyed it once! Or so you said at the time.
> But, y'know, if I don't amuse > myself at her expense once in a while, she loses that certain... edge.
Ah, but re: natto, you're outnumbered in this family. Michael's very first taste of something other than mommy's milk (or hospital formula) was a bit of natto slime. Which he adored. <g>
-- Kat Tanaka Okopnik Linux Gazette Mailbag Editor [email protected]
Breen Mullins [breen.mullins at gmail.com]
* Kat Tanaka Okopnik <[email protected]> [2008-03-18 18:46 -0700]:
> >> (Yes, I've tried the stuff - repeatedly. > >And enjoyed it once! Or so you said at the time.
But that was when you were dating, right? <g>
All men (and women, I think) tell similar porkies under such circumstances.
b.
-- Breen Mullins Menlo Park, California
Ben Okopnik [ben at linuxgazette.net]
On Tue, Mar 18, 2008 at 07:39:55PM -0700, Breen Mullins wrote:
> * Kat Tanaka Okopnik <[email protected]> [2008-03-18 18:46 -0700]: > > > > >> (Yes, I've tried the stuff - repeatedly. > > > >And enjoyed it once! Or so you said at the time. > > But that was when you were dating, right? <g> > > All men (and women, I think) tell similar porkies under such > circumstances.
I actually did enjoy it - once. Usually, it just doesn't taste like much
of anything at all (I don't actually find the stuff terrifying or
repulsive... except, as Kat notes, for dramatic effect - at which point,
I reel about with an expression of imminent demise and a hand to my
fainting brow.) Besides, we were already married at the time. I'm pretty
sure that we weren't when I first tasted it, at which point my opinion
was "Meh. This is what all the fuss is about?" I also happen to think
that the reported smell is mostly imaginary... although looking at the
stuff can certainly put you in mind of some very smelly substances.
Like many other Japanese foods, the stuff has to be literally perfect -
top grade, made in the last 3.2 seconds of a blue moon (underwater, by
40-year-old virgins, etc.) to be really good. At that point, however,
they're usually really good. Even natto can be described as "OK".
-- * Ben Okopnik * Editor-in-Chief, Linux Gazette * http://LinuxGazette.NET *
Paul Sephton [paul at inet.co.za]
On Tue, 2008-03-18 at 10:39 -0400, Mercedes-Lopez, Samuel CTR USA IMCOM wrote:
> Classification: UNCLASSIFIED > Caveats: NONE > > > Hello Answer Guy > > I was wondering if it is possible to cool a small amount of water for > drinking purpose using a small cilinder of liquid fill nitrogen (by > letting the water around the cilinder) is this possible and how long > will the water remain cool? > > Thanks > Sam
Dear Sam
Avogadros law states nPV = T, which states the relationship between pressure, volume and temperature for gasses (where [n] is one mole or approximately 6.22*10^23 gas molecules).
Liquid nitrogen is not cold when contained in a pressurised container, but only cools through evaporation. An analogy to this would be liquid butane in a butane lighter. At minus 196 degrees celcius (or 88 Kelvin) and at atmospheric pressure however, liquid nitrogen is constantly boiling, turning from a liquid into a gas. Your small flask of water would be cooled to this temperature while the liquid nitrogen lasts, if the liquid nitrogen were to be allowed to remain at atmospheric pressure.
It would theoretically be possible to constrain the amount of evaporation of the liquid nitrogen through use of a pressure valve coupled to a thermostat, thus keeping the water (and liquid nitrogen) just above the freezing temperature for water whilst ensuring optimum efficiency for usage of your nitrogen. Under these circumstances, and depending on the amount of heat allowed into the container, your nitrogen might last quite a long time.
... and yes, you might equally use such a system to cool beer ...
Having said that, the above is completely off topic.
This mailing group is associated with the Linux Gazette, and is meant to answer questions related to the use of this most amazing operating system. If you wish to know anything at all about Linux, feel free to ask. However, I doubt you will have much more luck here for answers to questions about basic chemistry and physics.
Paul Sephton
Ben Okopnik [ben at linuxgazette.net]
On Wed, Mar 19, 2008 at 01:50:43AM +0200, Paul Sephton wrote:
> > Liquid nitrogen is not cold when contained in a pressurised container, > but only cools through evaporation. An analogy to this would be liquid > butane in a butane lighter.
The less-than-perfect sealing of the standard industrial dewar, however, always results in a tiny amount of evaporation - which, of course, leads to a nice bit of condensation or even a tiny bit of frost on the outside of it, even in the hottest summer.
-- * Ben Okopnik * Editor-in-Chief, Linux Gazette * http://LinuxGazette.NET *