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Old 09-10-2012, 13:02   #16
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Re: Which do you suppose is more efficient?

my vote is to leave the nice COLD water IN the box
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Old 09-10-2012, 13:23   #17
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So I'm convinced to leave the cold water in. Now the question is; how do I keep my raw chicken from infecting all else as it floats in chilled water?
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Old 09-10-2012, 13:53   #18
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Re: Which do you suppose is more efficient?

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So I'm convinced to leave the cold water in. Now the question is; how do I keep my raw chicken from infecting all else as it floats in chilled water?
zip-lock bags, vacuum bags, tight plastic containers, shelves!
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Old 09-10-2012, 21:47   #19
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Re: Which do you suppose is more efficient?

No science here, just go with what seems to work for me.
I keep my melted ice water, but remaining ice does not float in it. Goes like this... Fill bunch of 2 liter soda bottles with filtered
water and freeze. (leave room for expansion when frozen)
When time to go cruising double zip lock bag frozen food...pork roast, chicken, pre made frozen french bread etc...towards bottom of ice box and put frozen water bottles on top, fill up
with bags of ice cubes and refrigerated foods. As ice melts in
soda bottles becomes our drinking/coffee/cooking water, and we
replace with block/cube ice.
Think the presence of the cold water not mixing with remaining ice helps keep all colder longer.
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Old 09-10-2012, 22:21   #20
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Re: Which do you suppose is more efficient?

When you think about it, it takes more heat energy to warm the melted ice and the ice than to warm just the ice.

So leave the water in...right?
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Old 09-10-2012, 22:48   #21
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Re: Which do you suppose is more efficient?

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We used to drain it constantly... then we stopped and kept the water. It's still cold, so acts as a cold thermal mass and regulates the temperature. Beer goes at the bottom and eventually is covered by the water. I can only get 2 beers before my hand is cold enough to cause pain. Keep the water.

Once the ice has completely melted... drain.
+1...
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Old 09-10-2012, 23:29   #22
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Re: Which do you suppose is more efficient?

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When you think about it, it takes more heat energy to warm the melted ice and the ice than to warm just the ice.

So leave the water in...right?
I've just read and reread Calder's book on Marine Refrigeration, which means I now have a firm and total misunderstanding of the topic (and no, it's not Nigel's fault, it's a great book). My biggest take away was that it's going to be expensive to redo my reefer...

When you drain the water, you're draining *cold* water. Because of the latent heat absorption, the water won't begin to really warm until all the ice melts. If you have a kilo of ice, it's going to take 334kJ of energy to melt it (from 0* C ice to 0* C water). We'll call it 80,000 calories (roughly). It's going to take that amount of energy whether you drain the water or not. However, it takes another 1000 calories to raise the melted water 1* C. If you drain it too soon, you'll waste that potential absorption. And, the water will conduct heat away from the contents much more efficiently than air.

But, like anything, there's a flip side. Air is a pretty good insulator, water is a much better conductor of heat. So, if you have poor box insulation, you'll actually increase the transfer of heat out of the box by having the sides in contact with water rather than air. So I guess the theoretical answer is... the better your insulation, the more benefit you derive from keeping the water.

While I love contemplating the theory of it, as a practical guy I prefer empirical results. Since we bought a boat with a dead cooling system, we've been using a combination of block and cubed ice. Although the number of experiments is less than I would wish, the beer always seems to taste colder when it comes out of a bath of ice water than just a cold dry icebox. I will, however, vow to continue this path of data point acquisition as often as I can...

JRM
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Old 09-10-2012, 23:55   #23
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Re: Which do you suppose is more efficient?

^The lengths some scholars will go to, in the quest for knowledge!
This is Nobel Prize stuff!
Forge ahead no matter the opposition....Yer a foot....um, leg end...legend, is what I means.
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Old 11-10-2012, 02:03   #24
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Re: Which do you suppose is more efficient?

There is no scientific question, keeping the water in will keep even a poorly insulated box cold longer. Not only do you have the issue JRM mentioned above, but every time you drain the water out you also let an equal volume of warm air in, which as it cools gives off a huge amount of calories.

If you want to try it some time, just take two identicle coolers. Fill both of them up with ice from the same freezer, and add an equal amount of ice to each (by weight). Then keep draining the water out of one, and let the other one sit. The one with the water in it will have ice in it long past the one without.


As another fun fact, super cold water (made by dissolving salt in water before putting it in the freezer) will cool beer down faster than an ice chest with just ice, or ice and water.
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Old 11-10-2012, 10:11   #25
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Re: Which do you suppose is more efficient?

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There is no scientific question, keeping the water in will keep even a poorly insulated box cold longer. Not only do you have the issue JRM mentioned above, but every time you drain the water out you also let an equal volume of warm air in, which as it cools gives off a huge amount of calories.

If you want to try it some time, just take two identicle coolers. Fill both of them up with ice from the same freezer, and add an equal amount of ice to each (by weight). Then keep draining the water out of one, and let the other one sit. The one with the water in it will have ice in it long past the one without.


As another fun fact, super cold water (made by dissolving salt in water before putting it in the freezer) will cool beer down faster than an ice chest with just ice, or ice and water.
I'm glad someone finally got to the important stuff! :>)
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Old 11-10-2012, 12:58   #26
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Re: Which do you suppose is more efficient?

If the drain pan gets slimy, you may need to add a little algicide.
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Old 11-10-2012, 16:17   #27
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Re: Which do you suppose is more efficient?

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Although the number of experiments is less than I would wish, the beer always seems to taste colder when it comes out of a bath of ice water than just a cold dry icebox. I will, however, vow to continue this path of data point acquisition as often as I can...

JRM
Exactly my thought too!

I know I can add a warm beer and have a cold one in 6 minutes if constantly agitated or 15 if just let to sit. In the water of course.

Try that in air and you get warm beer.
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Old 11-10-2012, 17:52   #28
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Re: Which do you suppose is more efficient?

this thread is funny in that I remember a few years ago when the same question was asked the crowd said it was bet to drain the water!
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Old 11-10-2012, 18:10   #29
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Re: Which do you suppose is more efficient?

Physics dictate that you drain the water. Otherwise, the water, which is very effective at heat transfer, will hasten the melting of the rest of the ice.

On a similar note, imagine that you are camping in a tent, and it is cold outside. You have a full bladder, and are wondering "Should I go outside and pee out all of that warm liquid, surely it is keeping me warm?". The answer is to go outside and relieve yourself, your body is burning calories to keep that stuff warm, it is not warming you.

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Old 11-10-2012, 18:39   #30
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Re: Which do you suppose is more efficient?

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Physics dictate that you drain the water. Otherwise, the water, which is very effective at heat transfer, will hasten the melting of the rest of the ice.

On a similar note, imagine that you are camping in a tent, and it is cold outside. You have a full bladder, and are wondering "Should I go outside and pee out all of that warm liquid, surely it is keeping me warm?". The answer is to go outside and relieve yourself, your body is burning calories to keep that stuff warm, it is not warming you.

Chris

Better would be to pee in a bottle and keep it in the tent. So long as the bottle is at a higher temp than the air, it will give off heat to the air, thus helping to warm the tent. Peeing outside just looses those calories.

The thing with water is it has a huge energy density (the amount of energy it takes to heat or cool it by one degree. Air is around .001 vs water at 4.2 J/cm^3. This means it takes roughly 4200 times as much energy to heat up a given volume of water compared to the same volume of air.

Again, as you let water out of the box, you let air in. The air which is nice and warm will quickly drop in temprature, while the stuff inside increases. Further, as heat is transferred into the box, that heat energy has very little mass to heat up, except for the stuff, because the air warms up so easily.
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