Instructables

Shrink your freezer to save energy for FREE!

Picture of Shrink your freezer to save energy for FREE!
So you got a full-size freezer or deep-freeze, but you don't use all the space. Whether you rent or may need the space later you don't have to pay for that wasted space. So I'm going to teach you NEUTRAL LOADING. The simple idea of loading insulating material to avoid paying to cool or heat air.

 
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Step 1: Materials.

Picture of Materials.
1.Several plastic grocery bags.
2.Styrofoam peanuts
3.Packaging tape.

Who said 2 wrongs don't make a right? Rather than throwing out those evil plastic bags and non-biodegradable styrofoam peanuts you can reuse them to save energy.

Simply fill one plastic sack with peanuts and then use another bag to cover the gap making a Styrofoam pillow. You can double-bag or use plastic bags as filler also. Seal the ends with clear packaging tape and your done. Make enough pillows to fill the unused space in your freezer or deep-freeze.

Step 2: Final Results.

Picture of Final Results.
Now throw your insulating pillows into your freezer or deep-freeze making sure to leave space for your fan. Make sure to leave plenty of circulation room. I prefer to fill the front half and leave a space behind so everything is evenly chilled. Putting things like icecream directly in front of the fan are great for fast freezing and prevents thawing crystals forming in the food.

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diy_bloke2 years ago
Stacking frozen water in yr freezer seems the best idea. If you need space in yr freezer, just remove as much bottles as needed and stack them in yr cooling space (where the butter, milk, soda and left overs are) That will help keep that space cool, without needing extra energy

counterproductive idea. With water jugs, you are paying to keep useless mass cold. only makes sense to fill a freezer with food you want frozen and/or more insulation.

well, obviously I never did a study on it and you might well be right, still it beats just keeping air, but I will give the insulation material a try too. Got masses of chips that come in boxes with stuff I arder

macrumpton4 years ago
Rather than just filling space with insulating materials it would make a lot more sense to add insulation to the non cooling walls of the freezer. that way you are actually decreasing the heat gain of the frozen items.

yes, the food should be surrounded (not on one side) as much as possible by insulation, barring being difficult to access and prolonging open-door-time.

We get a lot of peanuts here at work, so I just did this today with two large bags (since my freezer is pretty sparse), and I also have a lot of gel packs that have been in there for quite some time.  Hopefully it helps some.
bobstuart5 years ago
That's a nice point about loosing less cold air when the door is open, but maintaining something at temperature is, pretty much by definition, a zero-energy-exchange situation. Unsealed ice will sublimate and cause defrosting cycles, but that's about it. To really shrink a refrigerated compartment, you have to seal the insulation to the inside walls, much as you would insulate a house. You want to minimize the surface area of the cold space in order to have the least heat leaking into it.
ac-dc bobstuart5 years ago
Exactly. You don't have to leave the ice unsealed though, fill milk or other beverage bottles not quite full then after they freeze, put the lid back on. Putting the insulation around the inside walls of the compartment is indeed the best solution to increase insulation, and it should be a closed cell or at least solid backed insulation with the backing facing inward towards the food. Personally I prefer freezing ice instead for emergency cooling but lining all interior walls except the one with the coils in it is the most efficient. Both could be done if there is enough space left, or the other solution I don't see mentioned is to buy only a large enough freezer, or keep more food in it since that's why freezers come in fairly large sizes relative to the few convenience meals pictured.
marc925 years ago
Something similar to this can be done with toilets. You fill a plastic bottle with nuts and bolts or other heavy things and seal the top. Place this in the tank of your toilet where it is not in the way of the mechanics and you save water every time you flush. (if anyone wants to use this idea in the Keep the Bottle contest, go ahead, just mention me in the ible)
ac-dc marc925 years ago
As shooby wrote it is usually done with a brick, or nothing at all if you have a metal rod on the float as you can just bend the rod so the float is a little lower in the tank.
shooby marc925 years ago
traditionally done by placing a brick or rock in the tank.
We always just filled the bottles with water.
peguiono marc925 years ago
the problem with this is that trick is for older toilets or toilets that use a lot of water. If you tried to do this on a newer low flow toilet you will have trouble getting anything down because there is not enough water to complete the flush.
marc92 peguiono5 years ago
Yeah, I didn't take into account the age of the toilets. I guess all mine are pretty old.
Goodluck5 years ago
I don't think items with greater thermal mass would have any different effect on energy use than an insulator (bags, styrofoam, etc) except for the initial cool down. If I had extra space in my freezer, I'd freeze bottles of water. They can be used for more than just taking up space. Throw them in your cooler to keep your beer cold on a hot day then return to the freezer afterward. Better than buying 'disposable' ice/water. Also, in the event of an emergency - power outage, hurricane, tornado, earthquake, something else which disrupts your domestic water supply - you've got bottle water (once it thaws)!
lazyenvironmentalist (author)  Goodluck5 years ago
(removed by author or community request)
There is no continuous energy to keep ice cold, heat absorption is a function of surface area and insulation not density or heat capacity of the things in a freezer. You do not reduce the life of the fridge either, and in a disaster you are in a better position in having the freezer stay cold for multiple days longer if unopened or seldom opened. It is a very good, cheap thing to do, and if you have a disaster where you have to leave your home, taking some of that ice in your cooler to keep the food preserved (or share, or trade with neighbors for other vital supplies) is also very useful. The only negative thing about having the frozen water is in the event of a fuel or power outtage, it will require more time and heat to end up with a drink or for cooking or bathing, brushing teeth, etc., but you don't have to freeze ALL your water, it's just best to have every free space in the freezer filled with frozen water, if not other food.
ac-dc Goodluck5 years ago
I agree, keeping frozen water bottles in the freezer is what we have done for many years, and it is VERY handy to have them in there when power goes out, it keeps the food cold enough to prevent spoilage for a few days if there is a high enough ice:food ratio and the freezer isn't opened very often.

Another tip is to make some of them slightly salt-water instead of plain water (just don't drink it by mistake). Because salt water has a lower freezing temperature, it will begin melting sooner, at a lower temp than 32', keeping the freezer compartment cooler, keeping the food from thawing yet which will increase it's lifespan and degrade it's texture if frozen again later. There are other types of gells and liquids that are even better at absorbing heat at lower temperature than that of water alone, but they cost a lot more than salt and tapwater, plus the salt water is not a total loss, in event of emergency you can throw some dried beans in, heat, and make soup if it's not too salty.
lampajoo5 years ago
I'm pretty sure that water bottles in your freezer reduce your electricity use.
punxrus5 years ago
Man don't you eat anything healthy? LOL...Just kidding! Great tip! Keep 'em coming!
aaronjehall5 years ago
beats throwing those peanuts and plastic bags away. my recycling center only accepts the brown plastic bags. wonder why.
shooby5 years ago
Yeah, this is awesome! I can't believe I didn't think of it. Obviously the backs displace air, which could otherwise easily leave the freezer and be replaced with warm air when the door is open. I'm wondering if this idea could be optimized by using something with a greater thermal mass? Anyone thinking along those lines?
jeff-o5 years ago
Fantastic idea! So simple and smart. Unfortunately I can't take advantage of it because my freezer is stuffed (my wife likes to buy stuff on sale and freeze it) but if there's ever a large amount of space I shall remember this.
NoBonus5 years ago
Nice instructable! I had never even considered this and it is so easy and useful (anything that saves energy and cash for free with no downside is top of my list). Plus, I can reuse that nasty styrofoam.
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