# Dry Ice Cooooling



## endoit (Jun 20, 2010)

Does anyone use CO2 dry ice to keep their coolers and ice box cold on extended trips? A 25lb CO2 tank will produce about 3x 1.5 lb bricks of dry ice. Are there any safety issues on board with pressure building up in the coolers or using dry ice to extend the life of regular ice? Thanks for your input.


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## 123456Wannasail654321 (Jun 14, 2010)

Having a tank on board IMO is a bad idea. C02 gas is not what you want anyway. itst just going to vent and it will be gone with no cooling going on. and pressure could build up due to constant flow from the tank (which is pressurizing the ice box. if it it ait tight which is doubtful) another thing is that Tanks are heavy need to be secured (on land it hard enough) on a boat it would be worse) and if you lose one and the valve breaks off.... big trouble. it could hole you boat very easily if not kill someone.

Now Co2 pellets would better however you do need to be mindful of co2 build up in the cabin, which if it gets bad enough could knock you out and if not that you'll get a nasty headache. pressure problem will go away though and with good ventilation, no problems there. it certainly will keep your ice from melting but the pellets can burn your skin if you come into contact with them. So get blocks of c02 and wrap them but them in the very bottom. place ice bags on that it may work.

I'd just get some blocks of ice from the ice house, just to make life simple.


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## CapnBilll (Sep 9, 2006)

You will want venting. One good thing that much CO2 in your bilge and there's no worries about a fire.


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## CapnBilll (Sep 9, 2006)

I do use it for land trips. It works great, except a pack of regular ice will keep food cold, ...Dry ice will freeze it into a solid block. Also can cause freezer burns on meat. other than that it works great.


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## SlowButSteady (Feb 17, 2010)

Regular (water) ice is actually a better bet. It takes about 334 Joules (~80 calories) to melt a gram of water, but only about 196 Joules (~47 calories) to vaporize a gram of dry ice (carbon dioxide). So, solid water cools about 50% better than solid carbon dioxide. One advantage that dry ice does have is that as it sublimes, there is no liquid left behind to speed the conduction of heat between the stuff in the cooler and the sides of the cooler. But, if you have a working drain in the bottom of the cooler/ice-chest this effect is minimized. Also, if you want to keep something actually frozen, dry ice is the only way to go (short of an actual freezer), as regular water won't draw the temp significantly below 0˚C.


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## Nautichthys (May 2, 2010)

endoit said:


> A 25lb CO2 tank will produce about 3x 1.5 lb bricks of dry ice.


Are you thinking that you can make your own dry ice? Making bricks or pellets requires a machine at least the size of a small refrigerator. You can make dry ice snow by tying a heavy canvas bag over the horn of a CO2 extinguisher (or buy a purpose-made device that looks and functions the same but costs more). Dry ice snow isn't very efficient and doesn't last long enough to be useful for much.

Venting dry ice is always a concern as it will pool. Some people are more sensitive to CO2 buildup than others. Highly unlikely you could kill yourself with a block of dry ice short of sealing yourself in a barrel with it, but even a CO2 headache is not fun.


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## endoit (Jun 20, 2010)

Thanks for all the input. The unit that makes the dry ice bricks costs $500 and seems to be designed for commercial use. I was thinking of using a brick in a cooler with frozen foods and bricks of H2O ice and during the trips having access to frozen ice for the ice box. My Yeti coolers are well insulated for this purpose and likely would give me long insulation time without CO2 as well.


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## WanderingStar (Nov 12, 2008)

I used three small blocks of dry ice under around 14 blocks of wet ice on a delivery from Florida to NY. I put frozen foods at the dry ice end (over ice) and milk and eggs at the other end. It worked fine and kept cold for two weeks, adding cubes twice. (not too much of the cubes). The frozen meat will defrost. CO2 in such small amounts is not a hazard. It evaporates very slowly, and the boat isn't airtight.


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## rockDAWG (Sep 6, 2006)

Nautichthys said:


> Venting dry ice is always a concern as it will pool. Some people are more sensitive to CO2 buildup than others. Highly unlikely you could kill yourself with a block of dry ice short of sealing yourself in a barrel with it, but even a CO2 headache is not fun.


This statement reminds me the quote for Mark Twain "The reports of my death have been greatly exaggerated". The reasons:
1. The amount of dry ice is so insignificant compared the interior volume of the boat.
2. The boat is not air tight.
3. There is always movement in the boat.
4. It is thermodynamically unsounded since the entropy to maintain such homogenous system is impossible.

Frankly, I would not worry about it.


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## rockDAWG (Sep 6, 2006)

CapnBilll said:


> I do use it for land trips. It works great, except a pack of regular ice will keep food cold, ...Dry ice will freeze it into a solid block. Also can cause freezer burns on meat. other than that it works great.


If you lay/use your dry ice properly in the ice box, you will not have this problem.


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## Nautichthys (May 2, 2010)

rockDAWG said:


> Frankly, I would not worry about it.


I would agree. Unfortunately between Fark.com and working in Health and Safety for a long time I've developed a certain "caution". Somewhere, someone is sleeping in the bilge under the floorboards using a block of dry ice for a pillow...

Headaches on boats are far more likely to be CO than CO2.


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## SlowButSteady (Feb 17, 2010)

Nautichthys said:


> Headaches on boats are far more likely to be CO than CO2.


Or, an ill-timed gybe.


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## ottos (Aug 12, 2008)

A grocery store near me sells dry ice. I used it on a three day trip a couple of years ago. I remember it came with instructions on how to pack it in a cooler for most effective use. As I recall, if it lays on top, everything in the cooler will freeze; but to keep everything cool, put it on the bottom and put a couple of layers of newspaper on top, then pack the food in. Worked well for me.


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## rockDAWG (Sep 6, 2006)

Nautichthys said:


> Headaches on boats are far more likely to be CO than CO2.


You must have a fire place in your "Yacht". I want to sail with you.


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## hellosailor (Apr 11, 2006)

There was a similar thread on one of the forums last year. The OP got all incensed when folks said the whole idea was foolish and you simply CAN'T make your own dry ice in any reasonable quantity at a cost competitive to any othermeans of cooling, including buying it from a store. Took a couple of months, but eventually the idea got totally debunked and all parties agreed it is a screwball idea that can't and won't work. File under "perpetual motion machines", the same rules apply.

Yes, you can make dry ice. No, there's no point in doing it. Nothing to be saved in any way unless the Co2 Faerie is leacing you large CO2 tanks every night.

Hunt for the URL, then find a nice wooden stake and put it through the heart of the matter. "Die Vampire Die!"


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## Heinous (Mar 25, 2009)

I thought that stuff was just for making Funky Cold Medinas...


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