Freezer turned fridge

We have a 3.5 cf Danby chest freezer. It's AC, 100 watts. As a freezer, when empty, it ran basically 50% of the time, about 10 or 15 minutes on, 10 or 15 minutes off. About 1200 watts/day.

We bought a temperature probe controlled plugin for it and have it set to come on at 4C (39.2f) and go off at 3C (37.4f). It continues to cool down to -0.3C (31.46f) before starting to warm up again.

With a 10l (2.652g) frozen jug in it, it takes about 3 minutes of running to cool down and between 1.5 and 2.5 hours before it comes on again.

We're trying it now without a frozen jug, but even if its a 4 minute run time to a 56 minute off time, that gives us refridgeration with about 1.5 hours running on 24, or 150 watts per day compared to 1200 watts per day as a freezer.

The fact that it turns on so much less often also means it should last longer than normal.

Anyone else done something like this and have thoughts on it?

It sounds like a good experiment. Keep us posted on successes or failures.

I had a "chest fridge" for several years by doing exactly the same thing, but with a much larger freezer. It eventually died. I'm not sure if it was just going to die anyway or if something about running in fridge mode (extra cycling?) caused it to die. I liked it while it lasted.

Christopher Weeks wrote:I had a "chest fridge" for several years by doing exactly the same thing, but with a much larger freezer. It eventually died. I'm not sure if it was just going to die anyway or if something about running in fridge mode (extra cycling?) caused it to die. I liked it while it lasted.

I've had people tell me that's what would happen if I did this, for many years.

The problem with that theory is that at least in our case it's cycling much, much less often, not more.

At a guess, I'd say that old freezer of yours would have died sooner if it had been operating as a freezer.

At least going by what I've seen so far with this one.

I have what sounds like the same freezer, the same size and manufacturer anyway.
 I used it as a refrigerator in my cabin before I moved here full time. It was fine for a week or 2 vacation. Once I moved here full time I found it frustrating. It was just too small. I would have to unload half of it to get to whatever I happened to need. It is now in my shop as a beer refrigerator. It has 10 years of use just as you describe.

I can see it as being frustrating but after living for 4 years without refridgeration of any sort, it doesn't bother us at all right now.

By the time it starts getting on our nerves, I hope to be ready to switch it up to a bigger one running the same way, but with the condenser lines, motor and anything else that produces heat seperated from the box I want cool.

With the frozen jug taken out, it's looking like it's closer to 4 minutes on and 45 minutes off, which isnt as good as I hoped, but still pretty good.

We'll watch the timing again either later tonight or tomorrow.

After having the frozen jug in there for about 24 hours of it cycling at fridge temps the jug doesn't seem to have thawed at all. We took it out to test it without.

By the end we may decide having a frozen jug in it is a better plan than not having it.

I like the idea of separating the heat source.

I built a tiny house and managed to squeeze in 2 of those little Danby freezers plus a 6 gallon water heater into a 144 square foot house. One of my few regrets is not planning in advance to vent all that heat. In my climate 9 months out of the year the heat generated is a good thing. It lowers my need for heating in the cold months and extends the shoulder seasons where I want my windows open. It would be nice to be able to vent that heat in the summer months instead of having my AC unit pulling it out of the building.

Marty Mac wrote:I like the idea of separating the heat source.

I built a tiny house and managed to squeeze in 2 of those little Danby freezers plus a 6 gallon water heater into a 144 square foot house. One of my few regrets is not planning in advance to vent all that heat. In my climate 9 months out of the year the heat generated is a good thing. It lowers my need for heating in the cold months and extends the shoulder seasons where I want my windows open. It would be nice to be able to vent that heat in the summer months instead of having my AC unit pulling it out of the building.

Eventually I'd like to be able to have a seperated chamber to the side of the cooling box, that's insulated really well with vents to the inside of the room and to outside. Warm weather, vent it outside, cold weather, vent it inside.

I've also thought about making the cooling box with the ability to let outside winter air into it to reduce power use even further when the power from solar is diminishing.

But the main thing is getting the parts that release heat, away from the part you want cool. It's an insane design that shows how little regard humanity has for our resources.

My ranting about it gets even worse when talking about upright fridges/freezers that dump all the cold air out the moment you open them lol

Marty Mac wrote:I would have to unload half of it to get to whatever I happened to need.

That was a problem for us at first too. But once we loaded everything into milk crates, it was just a matter of pulling the top crate out and getting what you needed out of the bottom crate.

If you manage to pull that off please give us an update!

In my limited space the best I could come up with is to build an insulated cabinet to house the appliances and capture most of the heat to vent through the outside wall. To still have acceptable access to the fridge and freezer I think my idea seems like it would just allow humid air in the living space and eliminate any possible gains.

It seems to me that if the freezer is constantly turning on and off that will be hard on the compressor or the motor.

Can the freezer be set to a temp in the 39f range?  Much easier for the working parts.

Christopher Weeks   
I use a similar idea in my small upright refrigerator and it works very well.  Pull one container from the fridge for salad fixin's,  Ect Ect.
But Cristoms working with a freezer that wont even fit a milk crate! I know the same principle applies but he is extremely limited on space. Even with smaller containers I still had to unload half the little freezer.

I have been adding a digital thermostat in place of the dial/potentiometer for about 15 years. I have maybe done 8 of them that way. 4 were done for friends and family.

I like the digital readout because I had an upright freezer compressor die and when I went to the garage, I happened to see that the temp was 40 degrees. We were able to save all of the food.

I currently have 2 of the 7CUFT size. These came with a fridge mode. After looking them over, I don't see anything different about them except the factory dial allows for a fridge setting.

I do not believe adding the thermostat and using as a fridge full time or occasionally shortens the life of the equipment.

Marty Mac wrote:If you manage to pull that off please give us an update!

In my limited space the best I could come up with is to build an insulated cabinet to house the appliances and capture most of the heat to vent through the outside wall. To still have acceptable access to the fridge and freezer I think my idea seems like it would just allow humid air in the living space and eliminate any possible gains.

If I understand what you mean correctly then you still have the problem that you are heating the box you're trying to cool.

I don't remember if old chest style freezers were ever built with the exposed rack on the back but I do remember old uprights that did. They were still close to the box you were trying to cool but at least they were outside the insulation and metal shell. If there were chest freezers like that, they would be such a breeze to move it a few inches further away along with the motor, that was still getting warm under the box you want to cool. Then use high insulation value like low expansion foam to add at least a few inches around the sides and bottom and you'd have on that would likely operate at a fraction of the fraction the one we have uses. With the 'newer' ones it's the same principal, just have to skin and dissect it a bit first.

I highly doubt there's much value in adding extra insulation on the top of the freezer. We'll leave that part as is because it makes a good counter/shelf space when you don't need into it.

After giving it time to settle into a pattern, it's come to 6 minutes on and 26 minutes off. So about 4.5 hours on in 24 hours or 450 watts over the day or 18.75 watts per hour averaged out.

We're likely going to add frozen jugs of water back and see how long it takes them to melt.

18.75 is pretty damn awesome but not as good as it could be.