Anyone using dry ice to cool for several days??????

Ross · Jan 17, 2009

Jack, when Omaha Steaks ships a box of steaks they pack them in a 2 inch thick Styrofoam box with dry ice and after a week the dry ice generally gone. So yes it would work but I think that you need extraordinary insulation to make it practical.

Marco Garcia · Jan 17, 2009

I used to use it on my power boat. I had 2 coolers, kept 1 with frozen meats and dried ice ( I believe it was the 5lb. pack). On the othe cooler I had 1 bag of potable ice and dried ice, for drinks and cold foods. Keep the dried ice well packd in a zipperbag.
Before you go on the trip cool the coolers with ice, and dry them before you fill them with your trip meals. It stayed icy for 3 or 4 day weekends.

Marco

Tim R. · Jan 17, 2009

Yeah, but they are all dead now. It gives off carbon dioxide as it melts. Because carbon dioxide displaces oxygen, it is a health risk since we need oxygen to live. CO2 is an asphyxiant. It can cause headaches, drowsiness and loss of ability to maintain concentration.

There is also a burn danger with dry ice.

Ross · Jan 17, 2009

My ice box has 4 inches of insulation and I freeze water in gallon jugs for my ice supply. Five gallons will keep cool to cold for about five days in July and for more than a week in October.

Rob19574 · Jan 17, 2009

Jack - be careful as Tim mentioned with the displacement of O2 from the Co2. Particularly on a sailboat this would be of concern. Although I have never used dry ice before, I read it really only lasts about as long as regular ice does. The advantage to dry ice is that the temperature goes well below freezing where regular ice only maintains things just above the freeze point. For things like ice-cream it would work. Also - too much dry ice and everything around it freezes solid.

- Rob

Alan Johnson · Jan 17, 2009

I have used dry ice on trip from NY to Bermuda. The first time put the eggs too close and froze them solid. Next trip I put it in the bottom of the box, covered it with cardboard and then packed my entries from the bottom up, using the top ones first and worked my way down. Benefit, low engine hours for refrigeration and frozed meals

Ross · Jan 17, 2009

dry ice evaporates it doesn't melt. In the evaporation process we have a quality call vapor pressure. The higher the vapor pressure the faster the rate of evaporation. Dry Ice has a temperature of minus 175 degrees F. The closer that you can get to storing it at that temperature the longer it will last. Very high quality insulation is the only practical method of achieving this goal. In an ordinary ice chest the heat loss rate is very high which is why a bag of ice cube melts so quickly. Dry ice rolled up in a sleeping bag will last longer than same size piece wrapped up in a newspaper. In a hot climate the ventilation of the boat will disperse the CO2 quickly enough although the mouse in the bilge might not survive.

Tim R. · Jan 17, 2009

Ross said:
dry ice evaporates it doesn't melt. In the evaporation process we have a quality call vapor pressure. The higher the vapor pressure the faster the rate of evaporation. Dry Ice has a temperature of minus 175 degrees F. The closer that you can get to storing it at that temperature the longer it will last. Very high quality insulation is the only practical method of achieving this goal. In an ordinary ice chest the heat loss rate is very high which is why a bag of ice cube melts so quickly. Dry ice rolled up in a sleeping bag will last longer than same size piece wrapped up in a newspaper. In a hot climate the ventilation of the boat will disperse the CO2 quickly enough although the mouse in the bilge might not survive.

Well Ross, it is changing from a solid directly to a gas so it is not evaporating either. I believe this would be considered sublimation.

Ross · Jan 17, 2009

Tim, you are correct. When your hang wet laundry outside and it freezes and then dries, the water ice sublimates. Evaporation requires it to go from a liquid phase to a gaseous phase. Sublimation omits the liquid phase going directly from solid to gas. The final result is the same, you are left with a space where you once had a solid block. After you H2O ice melts and vaporizes you will have a space where once you had a solid block and if you look too soon you will find a puddle of liquid. I wonder with CO2 ice, if you confine it and warm it will it melt at high pressure?

Roy Udwin · Jan 17, 2009

I recommend Techni Ice (do google search to find it) - is not dry ice. Freeze it a few days before your trip and it will stay frozen in a cooler/icebox for 3-4 days.

Jim Kolstoe · Jan 17, 2009

Another factor is the starting temperature of the food. I have gotten good results by freezing things that I won't use for the first few days, and which tolerate freezing, to extend the storeage time. It effectively gives you additional ice without adding weight or sacrificing storeage space in the cooler. Another trick I've used successfully is to drap sleeping bags or blankets over our cooler to give it more insulation. Finally, especially if you have young children on board, try to limit how often people are opening the cooler up.
Jim Kolstoe, h23 Kara's Boo

jibes138 · Jan 17, 2009

Liquid CO2

Carbon Dioxide as noted goes from a gas to a solid, or vice versa at atmospheric pressure and a really cold temperature. There is a liquid phase of this compound and industry has played with it for some time as a cleaning agent since it has very good properties for degreasing parts. Industry was looking at it as a replacement for chlorinated solvents. Unfortunately highly specialized equipment is needed to keep the CO2 a liquid, it has to be a closed loop system or all the liquid would quickly change to a gas if left exposed at room temperature and atmospheric pressure (about 14.7 psi at sea level).. Plus CO2 is a greenhouse gas and controlled by the EPA for emissions. You could say that making dry ice you pull CO2 out of the atmosphere but that is not how they make it. They use a chemical compound, and break the molecule to get the carbon and combine with oxygen then freeze it. So the dry ice is adding to CO2 emissions.

jibes138 · Jan 18, 2009

Dry Ice Properties

Carbon dioxide has a very special property if you look at a phase diagram. This material has what is called a triple point. Most materials have a phase where when going from a liquid to a solid there is a mixture of liquid and solid for instance, at 32 degrees F water will be like slush. Carbon dioxide has a point where it goes directly from a gas to solid or a gas to liquid without this mixed phase. dry ice solidifies at about minus 107 degrees F at atmospheric pressure. To get liquid CO2 you need a lot of pressure, well over 100 PSI.

kloudie1 · Jan 18, 2009

We've used dry ice on a few 4-6 day trips.. By freezing everything first and layering dry ice on the bottom of the chest, the frozen stuff stayed frozen until the regular icebox volume had depleated and the cold stuff could be put in there. We used it because we could carry more frozen stuff in a smaller space. for a longer time. The gas problem was considered but the boat was open all the time and we figured that it would be blown out even though the gas is heavier than air.

Bill Roosa · Jan 18, 2009

Tidbits

CO2 will sublime in a sealed container and increase the pressure till it is great enough to cause it to stop subliming and start melting. Something like 750 psi if memory serves. Unfortunately the amount of solid CO2 it takes to fill the container is less than that required to achieve the pressure needed to liquefy it. So you can't practically make liquid CO2 from solid CO2. You can blow stuff up though so don't confine subliming substances.

All materials have triple points. Even rocks will sublime if you get them in a low pressure and high (to us) temperature state. Water ice will sublime if you lower the pressure or as Ross indicated the temp around it sufficiently. It will also "boil" at any temp above 33ish F if you lower the pressure.

jibes138 · Jan 18, 2009

Hey where do you sail? Isn't hickory about 50 miles north of Asheville? Are there oceans up in those mountains?

jibes138 · Jan 18, 2009

Dry Ice - Waste of money

Think of it this way, the dry ice only provides very cold ice. Water ice freezes at 32 degrees F but it gets as cold as you want it by lowering the temperature around it. What I have found works great for up to a week is make large blocks of ice yourself in your freezer. your freezer will typically be about zero degrees F. The ice you buy in store is typically much warmer than this and thus doesn't last very long. Freeze all the meat you want for the week at the same time. Take 1 cooler and completely fill it with the ice and meat for the week. Only open this cooler to remove the meat you want to de-thaw each day. By mid week most of the meat will thaw but it will still keep on ice for a few days. Now take another cooler and fill it with ice just for drinks. The ice in this cooler will not last long as you open it all the time and also if you put the ice in your drinks. I have used this method for years and so far have never used refrigeration on my boat so I never have to worry about power sitting on a hook. When the sun goes down go to bed or enjoy the stars so you don't waste juice on lights and when the sun comes up get up. You can make water ice be minus 100 degrees F also, same as dry ice if you have a way to do it.
Remember heat always flows from hot to cold so you are trying to keep the heat out of your cooler not the cold inside the cooler. Keep it out of the sun, use a white cooler, wrap the whole cooler with a thermal blanket, etc.