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Refrigerator root cellar freeze protection

protecting the refrigerator root cellar from getting too cold with a thermocouple device

The refrigerator root cellar has been doing a good job lately keeping the carrots from freezing during nights in the low 20's, but just barely. The thermometer we put inside was showing the low temperature to be 34, which was telling us if it got much colder the carrots might be exposed to freezing conditions.

I installed a thermostatically controlled outlet today known as a Thermo Cube with a light bulb plugged in.

When the inside temperature reaches 35 the light will come on and shut off when it warms up to 45.

Root cellar ebook

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I wonder if it would help if you put some large containers of water in the spaces between the shelves. As the water freezes, it'll give a little heat off to the surroundings. Plus it'll help even out the temperature in there.
Comment by Rena Mon Nov 19 17:59:52 2012
Rena --- Excellent suggestion! I like to keep jugs of drinking water on hand, and that sounds like a good spot to store them since the fridge isn't full this year, killing two birds with one stone.
Comment by anna Mon Nov 19 18:12:54 2012
I like the idea of the thermo cube. My "root cellar" is an insulated room originally built to hang meat and game by the previous owners. I am hoping it will maintain above freezing temps. So far, it has. We had one night of only 3 degrees and I put a single 60 watt bulb in there, but otherwise it seems to be holding. It has not gotten below 40 degrees so far. Being able to set a thermostat for the light bulb would be great, especially when we go out of town.
Comment by Deb Mon Nov 19 20:41:56 2012

It will be interesting to see if that works. Because for the water to starts freezing, its surroundings have to bee cooler than the water; there has to be a temperature difference before there can be heat flow.

A related idea;

If you warm some jugs of water up slightly next to the woodstove, and put them in the root cellar in the evening, it might give off enough heat to keep the frost away during the night. Of course you'd have to balance the heat flow from the jug to the cellar and from the cellar to the outside.

Comment by Roland_Smith Tue Nov 20 02:07:56 2012
A root cellar takes advantage of the steady 55degF temp of the ground down 5 feet or so from the surface. Yours has been placed to give convenient access and protection from varmints, but with so much surface exposed to the air, and not buried very deep, it seems little better (and maybe worse) than not burying it at all...Water has a higher heat content than air, so it can be used as a heat sink, but the volume required to make an adeaquate difference is pretty large. Using only a couple of gallons is probably insignificant (Sorry I sound so negative about what seemed like a great idea at first.)...And weren't the Nannycrats doing us a big favor by trying to take away our incandescent bulbs?
Comment by doc Tue Nov 20 07:42:02 2012

doc --- I disagree --- I think it's doing quite well. The earth enclosing the fridge has kept the humidity extremely high, which is what you need for root crops, and it hasn't frozen inside despite 10 days with lows around 22. As a frame of reference, the surrounding ground has frozen hard, and down in the floodplain where it doesn't get much sun, it's stayed frozen most of the day. Definitely much colder than our average November!

Other root cellar I've used (real ones) have required a light bulb when the outside temperature gets into the teens. (Most root cellars aren't dug five feet down because that's quite an engineering feat.)

Comment by anna Tue Nov 20 08:25:07 2012
Incandescent lightbulbs make good heaters (as opposed to light sources :-) ). But aren't the vegatables in the root cellar susceptible to light (like e.g. potatoes)?
Comment by Roland_Smith Tue Nov 20 16:08:46 2012
Roland --- Yeah, light is suboptimal. On the other hand, if it just comes on for an hour every few days, the light shouldn't be enough to cause sprouts. We were considering heat tape instead, but Mark didn't think it would give off enough heat.
Comment by anna Tue Nov 20 17:09:36 2012
You can get ceramic heating elements from about 125 W. They essentially only give off infra-red radiation. They do need to about 8 inches away from the vegetables when run at full power. Of course if you use them with a temperature controlled switch, they won't get that hot.
Comment by Roland_Smith Tue Nov 20 18:39:55 2012
Ideal carrot storage is at 32 degrees, so you may be just fine with the heat tape--I'm guessing it's the sort to keep pipes from freezing. The carrots won't freeze at "freezing" because of the sugars. Jugs of water are a good idea--maybe what you want is glass water jugs wrapped in the heat tape. . .
Comment by DrFood Thu Nov 22 23:37:48 2012
I wonder if you were to add extra rigid insulation to the side walls if that would help
Comment by jackie Sat Aug 8 22:43:50 2015
Why do people have to be so technical, it was an idea, and it works, thats all that matters.
Comment by Robert Craig Perry Thu Nov 24 19:04:49 2016