On the road tonight, DW mentioned that the governor of Virginia had declared a state of emergency in anticipation of Hanna. We briefly talked about what we would do if we were hit hard and a question came up.
Is it more efficient to save old milk jugs, fill them with water, and keep them in the freezer over long periods of time?
I always thought this was the case, but I’m wondering if anyone has real scientific knowledge/data to back it up?
I’m betting that, if you open your freezer door frequently, the thermal mass of 8lbs. of frozen water will help you out a lot. But what if you open your door very infrequently?
On one hand, I think that the thermal mass will still assist your cooling efforts because of the flywheel effect. On the other hand, mass is as difficult to cool down as it is to warm up. I wonder if a zero sum effect is in play? Something with low mass will not take much to cool but will require more “maintenance”, whereas an item with high mass will take a lot to get up to speed but not much to keep it there.
So, what say you?
Replies
If you are talking about long term energy savings then have the extra mass won't help.
But if you are talking about lasting without power, it will help. But I suspect only marginally unless it is realy low in stock.
Fill the freezer up with steaks instead of water. Then you can always eat them <G>.
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Bill's right about the long-term cost of keeping all that mass frozen. But just like those little blue thingies people freeze and then put in their lunch kits to keep their yoghurt cold till lunch time, bottles of frozen water inside your freezer will keep it cold in there longer with the power off. The more frozen mass you've got in there, the longer it will stay cold.
You should also throw a whole bunch of blankets over the top of the freezer when the power cuts out; the insulation in the walls of the average home chest freezer isn't very good and three or four wool blankets tossed over it will make a big difference in how long stuff stays frozen inside there.
When you open it, raise the lid slowly so you don't create a suction draft which will pull cold air out and admit large masses of warm air. Better to plan your 'withdrawals' so you make as few as possible, even if you have to keep the lid open a bit longer each time to get several things out at once.
With a full freezer and some additional insulation, you should be able to tough out three or four days without much stuff getting soft. Once the power comes back, check the bottom of the freezer for melt water and sponge/mop it outta there before it freezes stuff in place....
Dinosaur
How now, Mighty Sauron, that thou art not brought
low by this? For thine evil pales before that which
foolish men call Justice....
If you are really worried about surviving after the hurricane, stuff your freezer with half liter bottles of water at the first warning. It will hold your freezer and give you drinking water in a convenient size.
The thermal mass will help if there's a power failure, of course. And it slightly reduces the temperature swings as the compressor cycles, reducing freezer burn etc.
But even if you frequently open the door, it won't greatly affect operating cost -- the heat content of air is quite low. Probably more significant is the introduction of humid air which the freezer must then dry out.
To prevent the air exchange when the door is opened, you can just as well use empty sealed cardboard boxes, blocks of styrofoam, etc.
The thermal mass doesn't matter one way or the other with "maintenance", since thermal loss with the door closed is essentially constant -- a function of the insulation efficiency.
Don't forget that water expands as it freezes and can easily break it's container - or push the cap off. A minor problem if it stays frozen, but a real mess if it thaws out in your freezer.
An emergency preparedness guy once told me that freezing your emergency stores of potable water wasn't a good idea since you would have to thaw it before use - either to drink, cook, or use to clean wounds, etc. He also pointed out that store-bought bottles of water were safer since their bottles were sterilized before filling and the factory seals provided longer shelf life.
I keep the half liter bottles in my freezer all the time, they are handy to throw in the cooler and I have never had one break. I agree you shouldn't freeze all the water you have but if you are serious about storm preparedness you should have several cases of water along with what you store bulk for washing and other non potable uses.I agree store bought water keeps a lot better than tap water. I have found 3 year old bottles of water in my car that still tasted OK. Tap water can get pretty funky in a month or two.
I had read over the years that it is more economical to run a full freezer than an empty one, so was really surprised with all the answers here.
From the Economic Times: "Keep your freezer full to save energy
31 Aug, 2008, 2044 hrs IST
Keep your freezer full. It takes less energy to keep a full freezer cool than it does an empty one. If you don't have enough food to fill it, use plastic bottles filled with water"
And from the American Council for an Energy Efficient Economy:
"Manage Your Food and Storage Space
To keep your refrigerator from working too hard, let hot foods cool, cover foods, label items for quick identification, and keep your freezer full. "
John
Yeah, and just like the advice to drink 8 glasses of water, it's likely just urban legend.
In science it often happens that scientists say, "You know that's a really good argument; my position is mistaken," and then they would actually change their minds and you never hear that old view from them again. They really do it. It doesn't happen as often as it should, because scientists are human and change is sometimes painful. But it happens every day. I cannot recall the last time something like that happened in politics or religion. --Carl Sagan
You don't drink 8 glasses of water a day? :-)
John
Well, right now I'm having a kidney stone, so yes. But not normally.
In science it often happens that scientists say, "You know that's a really good argument; my position is mistaken," and then they would actually change their minds and you never hear that old view from them again. They really do it. It doesn't happen as often as it should, because scientists are human and change is sometimes painful. But it happens every day. I cannot recall the last time something like that happened in politics or religion. --Carl Sagan
Ouch, you need to be drinking something stronger than water!
John
I've got these little white pills I take with the water. One pill, one sip of water.
In science it often happens that scientists say, "You know that's a really good argument; my position is mistaken," and then they would actually change their minds and you never hear that old view from them again. They really do it. It doesn't happen as often as it should, because scientists are human and change is sometimes painful. But it happens every day. I cannot recall the last time something like that happened in politics or religion. --Carl Sagan
http://www.nola.com/hurricane/index.ssf/2008/08/check_out_these_emergency_food.html
Food tips from people who actually rode these out before.
Yes, keep it full and tightly packed. Also, bag everything... less of a mess to clean up later.
Rebuilding my home in Cypress, CA
Also a CRX fanatic!
I don't feel it's healthy to keep your faults bottled up inside me.