Our Chest Refrigerator

Two years ago, as we began the Extreme Green Renovation of our 1929 Craftsman bungalow near downtown Oklahoma City, I began researching refrigeration options. I found several very efficient fridges on the market - all of which were insanely expensive!

Then an internet search turned up this link -

http://mtbest.net/chest_fridge.html

http://www.builditsolar.com/Projects/Conservation/chest_fridge.pdf

This is an "insanely cheap" way to get maximum efficiency for your refrigeration needs: transform a chest freezer into a chest refrigerator by using an external thermostat.

So I got a free chest freezer from a friend, bought an external thermostat for $60 from an online supply house (see http://www.homebrewers.com/product/BE875/Refrigerator_Thermostat_by_Johnson_Controls.html as an example), and got set up. These are often available at local home brew stores.

I plugged the external thermostat into the wall outlet, and then plugged the chest freezer into the thermostat. I put the sensor (a long coiled wire with a metal sensor at the end) inside the chest freezer, resting it on a piece of metal towards the middle that was probably designed to hold a rack. You don't want the sensor at the bottom of the chest refrigerator, because cold air tends to sink so the items towards the top will not be properly cooled. I did not do any of the "surgery" on the thermostat described in the articles at the links above, in fact, I think I have a different kind of external thermostat. I run the metal wire into the chest refrigerator by simply laying it in place over the lip of the refrigerator on the gasket. The door closes just fine and the gasket prevents any cool air from escaping.

I organize the items inside the chest refrigerator in boxes and a basket. I put frequently used items (like butter and ketchup) in the basket. Meats, dairy, veggies - all have their own boxes. Leftovers go in individual containers right on top, so they are used quickly.

It took about 1 week to get used to the top down orientation, as opposed to the side view of a conventional refrigerator.

After about a year, I replaced the original chest fridge with a new chest freezer. The first one was quite large (18 cubic ft) and it was too large. I replaced it with a 10 cubic feet chest freezer.

The chest refrigerator needs to be cleaned each week. Moisture collects on the floor of the chest refrigerator and needs to be drained each week if you do not have it connected to a drain hose.

The chest refrigerator also provides an excellent flat work space in the kitchen.

Size and efficiency of the original chest freezer also matter. I started with one that was older, less efficient, less insulation, and nearly twice as large. It's power consumption was nearly twice the consumption of the smaller/newer chest freezer I bought in 2007.

The brand of external thermostat I have typically swings 4 degrees on either side of its setting, so I keep mine set at 37 degrees.

Why does this work so well?

+ In a regular upright refrigerator, every time you open the door, all the cold falls out. When you open the door of a chest refrigerator, no cold air falls out.

+ Freezers are much better insulated than refrigerators.

+ The chest configuration seems to me to hold more items than the same amount of cubic ft in an upright configuration. This may be because the upright configuration is broken up into shelves. With a system of boxes, you can make (for example) your "veggie storage area" bigger or small based on how much you have - you just use a larger box or an additional box for veggie storage if you have a lot of refrigerated veggies on hand.

Below are power consumption readings I have been taking with the chest refrigerator using a kilowatt meter, and below that is a summary of the steps to set up your own chest refrigerator..



7-17-07 7-24-07 10-27-07 12-07-07 1-21-08 6-23-08
KWH 3.5 6.81 1.31 0.94 6.09 8.02
hours runtime 184 359 98.5 70 507 411
days runtime 7.7 15.0 4.1 2.9 21.1 17.1
per day 0.46 0.46 0.32 0.32 0.29 0.47
warm season avg 83.95
cold season avg 58.4
Annual 142.35


1. Get a chest freezer. Newer is better than older, and smaller is better than larger.

2. Get an external thermostat. These instructions are for the Johnson Controls external thermostat referenced at the url above.

3. Place the long coil of wire and the temperature sensor inside the chest by opening the lid and finding a place to lay the sensor in the middle to upper part of the chest. I use twist-ties to hold it in place on a ledge that was already in my freezer (it is for a basket). The wire and sensor is pretty durable, but at the same time you don't want to bang it around.

4. Plug the external thermostat into the outlet, and then plug the freezer into the external thermostat. Hang the temperature control somewhere close by, and set it at 37 degrees F. If you want to monitor its power usage, get a Kill-a-watt meter (widely available on the internet) - plug it into the outlet first, then plug the external thermostat into the meter, and then the freezer plugs into the thermostat.

5. Let the chest refrigerator cool down, and then load it with the items from your other refrigerator.

6. Clean it every week.

Better Times Cookbook | Justpeace | Better Times | BobWaldrop.net |Access to Energy Conservation

For information about our plans for adapting our"urban homestead" to meet the looming challenges of peak oil, climate instability, and economic irrationality, see Gatewood Urban Homestead, the permaculture design for our home.

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