Filling Unused Space in Freezer

[gbanker]

Our freezer is charterboat size and as we are only two aboard we only have it about 1/4 to 1/3 full.

Would it help the efficiency of the freezer to have the empty space filled and if so, what might I want to use to fill it?

Would pieces of insulation loosely put in help at all?
Thanks

[Charlie]

I would take gallon jugs of water and fill them about 3/4 of the way full and then freeze them and place them in the freezer. That should help the freezer act as an ice box as well as a freezer.

[Abaco]

Bottles of water accross the bottom of the freezer with a basket on top for you food would work pretty well. Then you can pull the bottles and through them in a cool for trips in the dink when needed. Igloo Blue Ice would surve the same purpose. When I pack a cooler bag with Blue Ice, I often through a beach towel on top of the food to fill the void. You could do the same thing in your freezer and it would improve the efficiency.

[Richard Kollmann]

Putting added liquids in freezer to freeze will waste a great deal of energy so fill the empty space with moisture free insulating material. It you want permanent box size reduction use Dow’s water resistant Blueboard Styrofoam. The best solution for controlling energy use in large boat freezers are Zip lock bags ½ filled with Styrofoam packing peanuts. These pillow bags can be used on warmest side on box for more insulation and added to top of box as frozen items are used. This Zip lock pillows idea has been used by many boaters since someone suggest it to me for my first book 25 years ago.

[Unicorn Dreams]

I use styrofoam blocks to take up extra space in the box, I do like the idea of the peanuts though.

[GordMay]

Originally Posted by Richard Kollmann

Putting added liquids in freezer to freeze will waste a great deal of energy so fill the empty space with moisture free insulating material. It you want permanent box size reduction use Dow’s water resistant Blueboard Styrofoam. The best solution for controlling energy use in large boat freezers are Zip lock bags ½ filled with Styrofoam packing peanuts. These pillow bags can be used on warmest side on box for more insulation and added to top of box as frozen items are used. This Zip lock pillows idea has been used by many boaters since someone suggest it to me for my first book 25 years ago.

Or already frozen items, that your box doesn't have to freeze.

[Lancerbye]

I prefer to fill my freezer with food. There are many things that will keep better in the freezer than out. Popping Corn, Coffee, and any other dry foods that would otherwise use up cupboard storage space.

[avb3]

Originally Posted by Richard Kollmann

Putting added liquids in freezer to freeze will waste a great deal of energy so fill the empty space with moisture free insulating material. It you want permanent box size reduction use Dow’s water resistant Blueboard Styrofoam. The best solution for controlling energy use in large boat freezers are Zip lock bags ½ filled with Styrofoam packing peanuts. These pillow bags can be used on warmest side on box for more insulation and added to top of box as frozen items are used. This Zip lock pillows idea has been used by many boaters since someone suggest it to me for my first book 25 years ago.

I'm not sure how much energy is saved by freezing the peanuts versus water.

It seems to me that it makes sense to use the energy to freeze something usable like water, as opposed to styrofoam peanuts, which are not exactly an environmental friendly product anyways.

Additionally, once the item placed in the freezer is frozen (or at least be at the same ambient temperature as the rest of the contents), it doesn't matter what it is, it will not use more energy.

The important part is that the freezer is as full as possible.

[gonesail]

not only is it tough to freeze the water but the unit also works hard keeping it frozen .. that is why you would do better filling the space with styrofoam ..

[avb3]

I understand it takes different amounts of energy to lower different materials, however, once that material is lowered, I am not sure why there is a concern about use of energy to maintain that lower temperature.

Once a temperature is reached, it is a matter of insulation efficiency that will determine how much energy is required to maintain it.

I prefer my freezer to be full with usable items (drink or food) as opposed to an inanimate object. The only exception would be if I did not have enough food or drink to fill the space.

[Richard Kollmann]

Originally Posted by avb3

I'm not sure how much energy is saved by freezing the peanuts versus water.

It seems to me that it makes sense to use the energy to freeze something usable like water, as opposed to styrofoam peanuts, which are not exactly an environmental friendly product anyways.

Additionally, once the item placed in the freezer is frozen (or at least be at the same ambient temperature as the rest of the contents), it doesn't matter what it is, it will not use more energy.

The important part is that the freezer is as full as possible.

Styrofoam packing pieces (peanuts) in a plastic bag is insulation and a non or limited conductor of heat. Flexible insulating pillows are far better than filling box with heat conductors. Frozen foods retains flavor longer when tightly wrapped and sealed allowing natural air tumbles around inside box normalizing temperature of each item stored.

[Woodchuck]

Originally Posted by gonesail

not only is it tough to freeze the water but the unit also works hard keeping it frozen .. that is why you would do better filling the space with styrofoam ..

Water has a high thermal mass, meaning that it changes temperature slowly. It takes a lot of energy to freeze water but it releases that energy slowly. When properly insulated, ice stores cold like a battery stores electricity. When you open a freezer, the air that was filling the empty space inside warms up quickly. The same space, filled with ice, will not warm up nearly as fast. Otherwise you would fill your beer cooler full of cold air rather than ice.
Styrofoam has a very low thermal mass so it resists the transfer of heat. (The R value that insulation is rated with stands for Resistance to heat.) In order to be effective though, styrofoam needs to act as a barrier, keeping heat on one side or the other of an air seal. Foam peanuts that were just taking up space would have no more effect (and probably less) than air.

[avb3]

Originally Posted by Woodchuck

Water has a high thermal mass, meaning that it changes temperature slowly. It takes a lot of energy to freeze water but it releases that energy slowly. ...

Styrofoam has a very low thermal mass so it resists the transfer of heat. (The R value that insulation is rated with stands for Resistance to heat.) In order to be effective though, styrofoam needs to act as a barrier, keeping heat on one side or the other of an air seal. Foam peanuts that were just taking up space would have no more effect (and probably less) than air.

OK... NOW I remember my highschool physics... thermal mass. I guess I intuitively understood it but thanks for the reminder!

It just made sense to keep the frozen water in the freezer rather then the styrofoam peanuts, and you just confirmed and reinforced my intuitive memory.

[Palarran]

Figure one gallon of water weighs 8.3 lbs, water is 80 degrees when put in, so to get to 32 degrees its 48 degrees temp change so 48 x 8.3 = 400 btu's.

Now to freeze it, that's more. 144 btu's to change state per pound x 8.3 = 1,200 btu's. Now, lower it another 15 degrees (15 x 8.3) takes 125 btu's. So, to freeze a gallon of water it takes 400+1200+125 = 1725 btu's.

A small Seafrost BD system has output of 250 btu's per hour so it will take 7 hours to freeze the gallon of water. Max amp draw is 5.6 amps/hour x 7 = 40 amp hours. Is that a lot? Are these numbers right? I think so.

What you really don't want to do is pull the gallon of water out and let it melt exterior of the freezer. Put it in the fridge until it turns to liquid, then drink it.

I don't have years of experience with this but what I've found is that I drink beer at about the same rate it takes to cool it to just above freezing. So, I put a case of beer in at a time, I never freezes but is perfectly cold.

[Juniper]

I think it also depends on how your system works, if it's an engine drive you should have lots of cooling power when the engine is running so more mass helps, if you have a small overloaded system that runs most of the time but uses low power less mass might help.