ice box aka the fridge

[rogue_monkey]

for those of you who have sub freezing temps. here's a cheap idea to help save energy in the fridge. put water in bottles or jugs. put the water outside to freeze then once frozen put the bottles in the fridge. they will absorb the heat in your fridge thus lowering the temp. and haveing the fridge run a few less cycles. use a few jugs and have them on rotation.

free, simple and practical.

[Brock]

I do this with 2 liter bottles in rotation. It works out pretty well and my wife hasn't complained, yet...

[Darell]

Would it be easier to just store everything on shelves in the un-insulated garage?

[Brock]

easier maybe but my wife won't do it. I had our chest freezer in our insulated garage for a while, it barely ran but she hated going out there to get stuff, so I added more solar panels

[ken2400]

If one uses glass then add some salt to keep the glass from breaking.
Worked for me.

Need a fridge that uses air or water from the outside to cool it down or build one in a wall or window to the outside.

[TechGromit]

Originally Posted by Darell

Would it be easier to just store everything on shelves in the un-insulated garage?

That might work most of the time, but you don't want to have to worry about days when it becomes too warm outside where your frozen food may defrost. better to have in the the ice box so if it needs to keep it colder it will kick on.

[ikendu]

I came across this article about a guy that uses a chest freezer as a fridge.

Sounds workable.


http://www.builditsolar.com/Projects...est_fridge.pdf

[Darell]

ikendu -

GREAT find! I have long wondered why we have suffered with crappy appliances for so long. At a minimum a fridge/freezer should have a timer so that by default it only defrosts and/or makes ice during off-peak hours. Sucn an amazingly simple thing that no fridge has - to the best of my knowledge.

The only nits that I pick with the setup you point to:

1. Would be impossible for my daughter to use
2. Needs a separate device for the frozen good.
3. Dumping the cold air out is not as big a deal as many think (we hashed this out on CPF a while ago). If the fridge is full of dense, cold food and beverages, the amount of cold lost in the air dumping out is a small percentage of the stored energy.

But really - we can do so much better than we are. It took mandates to get us the efficiency that we currently have. But there is *so* much more that we could do if we just cared.

[jtr1962]

A lot of the energy consumption of today's refrigerators is from features such as ice makers and autodefrost. That being said, the chest freezer does better mainly by virtue of its superior insulation and lack of fans. Unfortunately, consumers want their refrigerators to be streamlined with thin walls. This means not much more than 1" of insulation when 2" or more could drastically cut power usage. Of course, all is not lost. With vacuum insulation panels getting cheaper all the time, it should be feasible soon to have our cake and eat it too. Another big source of losses is the interface where the door meets the cabinet. A lot of cold bleeds out along the perimeter. In fact, so much so that most refrigerators need to have heaters to stop moisture buildup along the seals. This wastes energy both for the heater and also because it presents a small but continuous heat load to the refrigerator interior. A better way is to have the door seals and everything in the interface highly insulated. This means basically that the steel cabinet doesn't curve around and intrude into the refrigerated area. Instead, you make that part out of pvc or some other thermal insulator, better yet with air pockets. This precludes magnetic seals of course, so maybe a spring-loaded door mechanism would work instead. And put the freezer in the center of the refrigerated compartment instead of on top or bottom or on one side so that the thermal gradients are smaller. All these things combined with vacuum insulation panels could probably reduce the power consumption of today's refrigerators by two-thirds or more.

I shouldn't talk-we're still using a 30 year old energy guzzler. Recently the defrost heater went, and I thought it was beyond repair. As a result, we bought a new one but it never made it in the door (too big by 1/2" thanks to an unknown projection for the ice-maker hookup). So I had incentive to figure out how to fix the old one. Maybe it's for the better. Hopefully in a few years or whenever the compressor finally gives out we'll see better-designed refrigerators. Besides all that, today's appliances are made like crap. While we might save energy running the new fridge, what about the energy required to make and deliver a new one every 7 or 8 years because they aren't designed to last? That must surely outweigh the energy savings compared to just continuing to use the 30 year old fridge we already own. In addition, it probably saves us a bit on heating bills by bumping the kitchen temperatures up a few degrees during heating season (which lasts longer than cooling season).

[jtr1962]

I thought this might be of interest. They made a prototype 126 liter refrigerator/freezer cooled by thermoelectric modules (i.e. peltiers) instead of a compressor. The part I thought relevant was the fact that they managed to get the fridge to meet energy consumption requirements despite the fact that thermoelectrics are far less efficient than compressors. They did this by paying attention to small details, and also using vacuum insulation panels in the freezer.

[ikendu]

We are preparing to buy a new fridge. The Energy Star units will use about half of the electricity of our current model.

Before we buy, I would love to find an amazingly efficient fridge but it looks like the latest Energy Star models are almost as good as it gets short of the guy in Australia's design (chest freezer).

[shadow0000]

Well i might refer up to go and search in some site that are related to your problem like a some site that like this ice industry...




____________________
Manitowoc Ice Machine

[ljgail]

I'm an idea person. Is there any reason why one could not attach insulation, such as foam slabs, to the non-working parts of a regular fridge to increase its efficiency? Jeanne in Maine

[luckybucket]

Adding foam to the outside should work to increase the efficiency of your refrigerator. The problem is that I'm not sure if it will cause condensation which will lead to mold if it stays wet for too long. I like Kens' idea of using outside air to pump into the refrigerator in the wintertime. Actually I've been wanting to do this before I even knew cpfgreen existed. I wouldn't use water just for the fact that it requires more parts and therefore more complexity. Has anyone tried this? I'm trying to think of a simple and reliable method to maintain the temperature in the ice box. Maybe a flap and small fan that turn on and off.

[reptiles]

I had a similar set-up at one time. I ran a 6" insulated dryer hose from refrig. to the outside. This was connected to a small computer-type box fan to pull cold air in.

Within the 6" intake hose was a smaller ~2" exhaust hose to outside. You can't pump cold air in, without venting air out.

There were a few thermocouples hooked up to an old Radio Shack Model 100 computer.

A BASIC program ran that monitored refrigerator temperature and outside temperature, and engaged the fan.

The original refrigerator thermostat was set to turn on at 41F. as a safety feature, so food wouldn't spoil if it were too warm outside.

Otherwise the program would monitor the refrigerator temperature and if the following conditions were met, the fan would suck in cold air:

1) Door is closed and
2) Outside temp is less than 39F and
3) Refrigerator temp is greater than 34F (to avoid freezing) and
4) Refrigerator temp is less than 40.F

Then the fan runs, and the computer cycles through the above "if" conditions until any one of them changes, then turns off the fan until they are all true again.

Essentially pulling in cold air until refrigerator was between 34 and 39F.

This might not be the most elegant way to accomplish it, but it worked fairly well most the 4 months of Winter in Pennsylvania. The compressor rarely came on at all when it was cold outside.

Intake air was collected in the shade of the North side of the house (in the bushes actually.) Both intake and exhaust air was filtered through fine stainless steel screen mesh to keep any wee beasties out.

The only problems I noticed was when a lot of dense items (multiple 12 pak cans, etc) were added to the refrig when it wasn't below freezing outside. It would take a while to chill them.

That refrigerator went to an ex, and I never actually got around to cutting up my new refrigerator. I was waiting for the warranty to expire.

If/when I do this again, I think I'll use one of those those new single board computers or PIC controllers.

Hope this might help someone starting on this project (or amuse any engineers out there.)

Cheers,

Mark