Filling Unused Space in Freezer

[ATC]

When we were sailing, I had made a foam sheet that covered the inside of the ice box/refrigerator. By placing this on top of the items to be refrigerated we reduced our area of space to be cooled. This allowed us to store other items on top of the foam sheet, such as bread, etc.

[atoll]

for a long term storage,you may be better off filling water bottels with anti freeze/water mix,as water only freezes at 0.c where as for stuff to be properly frozen ideally you want -10-18 0.c

filling with a 40/60 mix will hold the temp a lot lower than with just water.

also ideally you dont want to be digging stuff out from the bottom,keep frozen water bottels at the top for drinking.

we pack bread on top of deep frozen stuff which acts as a good insulator,then beer right at the very top,so it doent freeze completly

[Palarran]

Look, you can screw up a lot on a boat, but freezing your beer - totally unacceptable.

From an energy view, antifreeze won't matter at all.

[SaucySailoress]

If you want to be a good friend, fill up ice cream containers with ice cubes from a local bar (if they're your friends too!!) then share them out back at the anchorage!

We freeze milk bottles with water in 'em - that way they help keep temp of freezer low. And when we want to, we can take 'em out and have ice cold water as it melts in the desert sun... delicious.

[David_Old_Jersey]

I'd pack it out with Freezer blocks (blue ice?) - can always find a use for a block of cold. Downside is not drinkable (I think ). As they retain cold very well I figure they don't take much energy to maintain.

No science involved

[Mark Johnson]

IMO, adding insulation, (preferably sealed), is the answer. Better yet, if one wants to cut their Ah consumption in half... Don't use a freezer at all. We have found refrigeration alone perfectly sufficient. When we turned it down to the point that we could make ice with trays against the cold plate, the Ah consumption almost doubled! (We like our 25 or so Ah / day refrigerator!)

If you have a spillover design, you could seal off one side with a removable, but air tight foam dam, and adjust your "cold side" to refrigeration only. Then back at the marina you could remove the foam dam and return to land lubber style amenities... M.

[sailorboy1]

I don't think adding anything to the empty space makes any differenece to the efficiency of the system. Unless it of course is insulation and you add it along the sides therefore changing the mechamical/thermal properties of the box.

But adding water bottles etc will change the run time to get up to temp and the total heat lost opening the box due to the mass.

In the end once everything in the box is cold all it cares about is the heat transfer across the sides, which is all about the temp differene on both sides. So all you can change is the temp on the inside and the insulation or the box.

Now depending on how you charge your batteries, and/or if you have an engine driven refrig system, it makes a difference as far as total boat efficiency, but that's a different topic.

[Pacey16]

Might not be the best idea to fill water bottles with antifreeze incase someone accidentally drinks the stuff.

[LakeSuperior]

What scares me about this thread is that there are posters offering ill conceived advice because they have little or no understanding of heat transfer. Now I'm wondering how valuable the advice is on the topics I need advice on. Just a thought here.

The primary issue with a freezer having empty space is advection or the transfer of heat by mass flow (warm air displacing cold air).
Advection tends to be minimum if the freezer accessed through a door on the top because cold air is more dense than warm air and will tend to stay in the freezer. Consequently, from a energy consumption point of view it doesn't really matter if the freezer is empty or full on a day-to-day basis. In fact, if a cubic meter of air at 80 degrees F is displaced it takes about 30 BTU's to cool it to freezing. If a cubic foot of air is displaced requires roughly 1 BTU to cool it to freezing.

However, if there is a fair amount of air exchange each time the freezer is opened the big issue is condensation. Warm moist tropical air cooling down past the dew point will cause significant frost to accumulate.

If you fill the empty space with water bottles or foam peanuts or whatever there is a one time cost to cool it down. Averaged over 6 months or a year of freezer use this cost is negligable.

One advantage to using frozen water is in the event of a compressor failure the frozen water would help keep things cool for a couple extra days when compared to the foam.

[Lancerbye]

Originally Posted by Palarran

Look, you can screw up a lot on a boat, but freezing your beer - totally unacceptable.

From an energy view, antifreeze won't matter at all.

Totally agree with that. Freezing beer changes it's characteristics. Drinking that stuff will have you spending a lot of time in the head. Don't ask how I know this.

[atoll]

was in no way advocating freezing beer,just chilling it enough to stay frosty for longer than 5 mins in the tropics,this is an exact science,perfected after thousands of tests........

[svcambria]

Originally Posted by LakeSuperior

What scares me about this thread is that there are posters offering ill conceived advice because they have little or no understanding of heat transfer. ...
The primary issue with a freezer having empty space is advection or the transfer of heat by mass flow (warm air displacing cold air)...

Ah, I have had a running argument with a friend about this for years. She thinks the best approach is to have the box absolutely stuffed with food, to the point one has to squeeze the door shut. I have always felt this would require conductive heat transfer, not very efficient, better to have a little fan and push cold air around. She maintains the stuffed box will loose less heat when opened...

Michael

[Palarran]

Originally Posted by LakeSuperior

What scares me about this thread is that there are posters offering ill conceived advice because they have little or no understanding of heat transfer. Now I'm wondering how valuable the advice is on the topics I need advice on. Just a thought here.

It's worth more then what you paid for it.

[Mark Johnson]

Originally Posted by svcambria

Ah, I have had a running argument with a friend about this for years. She thinks the best approach is to have the box absolutely stuffed with food, to the point one has to squeeze the door shut. I have always felt this would require conductive heat transfer, not very efficient, better to have a little fan and push cold air around. She maintains the stuffed box will loose less heat when opened...

Michael

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.

[svcambria]

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.

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

Michael