Filling Unused Space in Freezer

[Lancerbye]

Originally Posted by svcambria

Better than an empty box, certainly. But better than a box that is fractionally full - say 3/4 full?

Michael

It gets that way on it's own soon enough.LOL

[Bash]

I fill the unused space in my freezer with a 1.75 liter bottle of Tangueray.

[acheron]

Richard is right. Mass not needed takes more energy to waste. Better to displace the air somehow to make the box smaller in effect.

[Lancerbye]

Originally Posted by Bash

I fill the unused space in my freezer with a 1.75 liter bottle of Tangueray.

That is way to expensive for my budget. I would lock it up in a safe. LOL

[avb3]

Lot's of opinion (some agreeing with mine), some factual (again agreeing with mine ) but no solution.

So, Google being my friend, where do we find factual information?

I found a few sites, but perhaps this one that I would view as being credible, says it best in lay person language. Fortunately, it agrees with me again

California Energy Commission on refrigerators and freezers.

[Palarran]

Well, it's really fortunate that you agreed with me

FWIW - This has been a good thread.

[svcambria]

• avb3 - I can see why you point out this site; I can use it too...
• Too bad i can't get rid of the little "bullet" format copied over from that site...
• "A full refrigerator retains cold better than an empty one. If your refrigerator is nearly empty, store water-filled containers inside. The mass of cold items will enable the refrigerator to recover more quickly after the door has been opened. On the other hand, don't overfill it, since that will interfere with the circulation of cold air inside. The simplest solution is to buy the right size for your family in the first place." (Italics mine.)

Michael

[avb3]

Originally Posted by Palarran

Well, it's really fortunate that you agreed with me

FWIW - This has been a good thread.

Yes, it is always good to be agreeable lol!

And I agree, it is a good thread.

[doug86]

Imagine 2 one gallon milk containers; one empty and one full of water. Put them both in the freezer for a week. Now, take them both out for thirty seconds and put them on the counter. At the end of thirty seconds, measure the temperature of the contents of each container. The one with water will still be frozen, the empty one will practically be at room temperature. Now, when you put those two containers back in the freezer, the freezer will have to remove the heat from the empty container all over again, whereas the frozen one will barely require any work at all from your freezer to stay at its temp. True, it takes less energy to remove heat from a gallon of air than a gallon of water, but ANY heat that needs removing by your system reduces its efficiency, which is why displacing air in a freezer makes it more efficient.

If empty space didn't make a difference, then we would all be freezing walk-in size freezers with 1qt cold plates.

[LakeSuperior]

Originally Posted by Mark Johnson

We have also found that a full refrigerator, once completely cooled down, is way less energy consumptive than keeping an empty box equally as cool. This has also been the experience of pretty much all the cruisers we know personally.
M.

How did you measure the difference in energy and what was difference?

[LakeSuperior]

Originally Posted by doug86

Imagine 2 one gallon milk containers; one empty and one full of water. Put them both in the freezer for a week. Now, take them both out for thirty seconds and put them on the counter. At the end of thirty seconds, measure the temperature of the contents of each container. The one with water will still be frozen, the empty one will practically be at room temperature. Now, when you put those two containers back in the freezer, the freezer will have to remove the heat from the empty container all over again, whereas the frozen one will barely require any work at all from your freezer to stay at its temp. True, it takes less energy to remove heat from a gallon of air than a gallon of water, but ANY heat that needs removing by your system reduces its efficiency, which is why displacing air in a freezer makes it more efficient.

Nice try but the reality is the heat transfer rate depends on the temperature difference so the frozen water jug will have actually absorbed more heat sitting on the counter (because it doesn't warm up as fast and therefore maintains a larger temperature difference). Consequently, when you put it back in the cooler the refrigeration will actually have to work a little longer to remove the extra heat from the frozen water.

[doug86]

Originally Posted by LakeSuperior

the refrigeration will actually have to work a little longer to remove the extra heat from the frozen water.

"extra heat from frozen water" .... funniest thing I've read all year.

[LakeSuperior]

Originally Posted by doug86

"extra heat from frozen water" .... funniest thing I've read all year.

I figured that would get a laugh!

[acheron]

Originally Posted by doug86

Imagine 2 one gallon milk containers; one empty and one full of water. Put them both in the freezer for a week. Now, take them both out for thirty seconds and put them on the counter. At the end of thirty seconds, measure the temperature of the contents of each container. The one with water will still be frozen, the empty one will practically be at room temperature. Now, when you put those two containers back in the freezer, the freezer will have to remove the heat from the empty container all over again, whereas the frozen one will barely require any work at all from your freezer to stay at its temp.

No. If the rate of transfer of heat is the same then there is no difference. Actually the smaller item can be better in the long term. The temperature is not important, it is the sum of themodynamic energy that is important.

You just want to displace the air : use the foam blocks or empty containers.

[Captain Bill]

This has been a good thread, but I think the real answer depends on a lot of things. The biggest being if the unit is top loading or front loading. The OP apparently has a big unit only partially filled, so if it's front loading when he opens the door he dumps perhaps 2/3 of the volume on the floor which is immediately replaced by warm air. If it's a top loader, he gets a little turbulence when he opens it and roots around in it so he dumps about 1/10 of the volume over the edge. Let’s assume for a moment that the insulation level is equal and the inside temperatures are set the same, so heat gain through the walls of the unit are equal. On the front loader how much space is filled with warm air matters a lot more than on a top loader. If that space is filled with frozen stuff it cannot be occupied by warm air. That frozen stuff does not absorb heat very fast when compared to dumping out the cold air and replacing it with warm air. If the front loader is 75 or 80 percent full a lot less space is available to be filled with warm air therefore the amount heat that must be removed is lower. Suggestions of using an antifreeze mixture instead of water could be dangerous, but a brine mixture will accomplish the same thing without risk of bodily injury should someone attempt to drink it. A bottle of frozen brine would act much like a holding plate refrigeration system once it was down below its freezing point. If we were talking about a unit that was never opened then the heat gain would be the same in both units and the compressors would run the exact same amount of time. I think that the difference would be that the less full freezer would run more often and for shorter times than the fuller freezer as the thermostat is controlled by temperature, not heat. It would take longer for the temperature to rise in the fuller freezer and also longer for it to be cooled back down. Most compressors have a big power draw at startup so the more starting cycles one goes through the more power one will use over time, so the less full freezer will use more power, everything else being equal. I’ve not calculated how much more.

I suppose the ideal situation would be to have a big bunch of brine (assuming you had not already filled the space with useful stuff) acting as a holding plate during the day and run the compressor at night when outside temperatures were lower and cooling (assuming an air cooled system) more efficient or to run it when excess power was available from solar or wind after the batteries were completely charged, but that would take a power management system much more sophisticated than any I've seen.

I think that anything that has thermal mass and occupies the space will help as long as it isn't raised to "room" temperature. Plastic bags filled with Styrofoam peanuts probably has more thermal mass than air, but their temperature will rise very quickly when compared to a jug of frozen brine, so if you have to take it out for a couple of minutes while you root around, you'll have to cool the thermal mass of the peanuts again which may be more than the air. A gallon of brine on the counter will absorb some heat, but I would think not as much as the peanuts as air in the bag warmed by the counter could circulate amongst the peanuts and transfer heat by convection as well as conduction and radiation. The frozen brine would be pretty much limited to conduction and radiation.

My 2 cents change always welcome.