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In my garage I used to use an older Dometic propane freezer as a beer cooler. I set the thermostat to the freezers warmest setting and it would maintain 36 to 37 degree internal temp summer and winter. Perfect for a cold beer. Well that freezer died and now I need to come up with something else. I ran accross a paper on the internet written by a guy in Australia. He took a small elec freezer about 5cf and fitted it with a thermister switch. He took the actual temp sensng component out of the switch and soldered it to a wire and then put that component inside the freezer, the other end of the wire is soldered to the circuit board where the component was originally. He set the thermister to the temp that he wanted the freezer to be and then plugget it in to a wall outlet. He says that the freezer compressor runs about 90 seconds every hour and in 24 hours uses about .1 kw or 100 watts. His ambient temps were a modest 70 degrees at the time but even if the power consumption triples during the summer that is still almost nothing. I waste more power than that a day keeping the didital clocks in my house on. Here is a link to the paper: http://mtbest.net/chest_fridge.pdf
Anyway it looks very interesting, so I might keep looking into it and see if I can fink a suitable thermister switch locally.
Larry

I have seen that webpage and it looks interesting. I have since found many others online who are using it as a regular fridge, mostly with a lot of success. The key seems to be to find a unit that is manual defrost, sized right for your space availability / needs and has nice storage setup with multiple sliding shelves for access.

Salud amigo...

Well I have found and ordered the needed thermister sw. Only $68 delivered. Now I just need to find a good used small chest freezer. I have been looking on Craigs list and most of what I am seeing is $60 to $100. I am not in a hurry so I will keep lookng until I find a really good deal.
Ron, since this is just for drinks, I am not too concerned about racks, I can use the lift out racks that came with the Dometic. If I was trying to talk my wife into using it in her kitchen that would be another hurdle.
Once I get it up and running I'll hook my Killawatt meter to it and I will be able to give some real world energy draw information.

Do they have any tiangis / swap meets around where you live? You can often find good deals on some chest freezers at those events...

I am in San Diego now for the summer, too hot in Bahia. so I can check garage sales and swap meets. Craigs list is just so easy.
Larry

I think that I bought half of my building materials off Craigslist. Found some really great deals on some killer windows, skylights, door hardware, plumbing supplies and electrical wiring as well as our batteries for the solar.

You mean some people just go shopping without checking CL first???

Here is a good step by step method of how to do it if anybody else is interested...

How to Convert a Chest Freezer into a Refrigerator

If you are looking for new ways to green up your lifestyle and save large amounts of electricity this is one of the best! Regular upright refrigerators use a lot of power. But there is a very simple and inexpensive way to convert a chest freezer into a refrigerator that can save you tons of electricity and money for years to come.

Things You'll Need:

* Chest Freezer
* External Thermostat
* Battery powered aerator fan (optional)

Step 1
Even if you already have a chest freezer please read this first before going to the next step. While any freezer will work some are more suitable for this application than others.

* Get one with manual defrost. Avoid units with automatic defrost since you won't be trying to keep the walls from icing over (plus they use a lot more electricity).
* Smaller isn't always better. Larger freezers typically use less power per cubic foot than a smaller one. You can determine this by comparing each units energy guide that shows the estimated electrical usage per year. Of course if space is limited then you might not have much of a choice anyways.


Step 2
Since chest freezers run too cold, even on the lowest setting, you will need an external thermostat to control the temperature. These can be purchased from most brewing supply stores for about $60 (I think mine came from Home Brewers Outpost).

Basically all you do is plug the external thermostat into an outlet then plug the freezer into the thermostat. For the thermostat to work properly you need to place the temperature probe somewhere inside the freezer. Snaking the wire in from the back underneath the lid and taping it to the inside wall works very well.


Step 3
A battery powered aerator fan is completely optional but a highly recommended addition. By placing this fan at the bottom of the refrigerator it will push the colder air to the top resulting in a more consistent overall temperature.




Step 4
That's it! How much you will actually save may vary based on age/condition of freezer, insulation, usage, external temperature, etc but most report a savings of at least 50% and many as much as 80-90%. Some tips like keeping the unit in a cooler part of the house and well ventilated will definitely help you to maximize your energy savings potential.

Darn it Ron, why didn't you post that a few days ago? I coud've save lots of time on Google finding the same thing. I'm still looking for the chest freezer but I found the external thermostat here:


Johnson Controls - Single Stage Digital Temperature Control 120/240v

Surprisingly simple project once I started looking into it.

Larry

Sorry Larry - wish I knew you were looking for it. I thought I was the only oddball here thinking about these things...



Even though we recently bought a 12 cu ft whirlpool electric fridge that seems to be pretty economical, I am still thinking of trying this anyway just keep as a beer/soda/overflow fridge. I really like the controller you found.I talked to a guy in Canada who did the conversion and he also recommends giving the thermostat a thin coating of silicone to keep the thing from cycling each time the door is opened.

Siloicone on the probe? I guess that would thermally insulate it. From reading the literature about the thermostat, supposedly you can adjust the cycles through the key pad on the thermostat. I guess I will just have to wait till I get it all together and play with it to see what works best.
Larry
PS I am kind of surprised that no one else is interested in elec refrigeration that is very low draw on the solar system.

Originally Posted by rplarry

PS I am kind of surprised that no one else is interested in elec refrigeration that is very low draw on the solar system.

I am very interested.....just watching....We are planning on being there the end of September. Will you be around so I can peak at your new cooler or are you doing it up here?
Been a little busy with medical stuff in our household.....I am hoping my stuff even works after more than a year away.....
Frank

Originally Posted by rplarry

Siloicone on the probe? I guess that would thermally insulate it.

What the guy told me was that it just delays the reaction time. When you open the fridge door there is a vacuum pull on the air that can make it appear for a moment that the temp has increased past the setpoint. When you shut the door the cold mass of items in the fridge usually will pull the temp back down within the working range quickly. By placing a very thin coat of silicone on the thermostat he says it will make the fridge react to changes more slowly which will reduce the compressor run time.

Originally Posted by rplarry

I am kind of surprised that no one else is interested in elec refrigeration that is very low draw on the solar system.

I would wager that more are interested on some level but think this is much more complicated than it really is.

Originally Posted by soulpatch

I am very interested.....just watching....We are planning on being there the end of September. Will you be around so I can peak at your new cooler or are you doing it up here?
Been a little busy with medical stuff in our household.....I am hoping my stuff even works after more than a year away.....
Frank

Might be a good idea to pick up the chest freezer before you get to BOLA. I am not sure how available used ones are in the BOLA area.

Another thought - maybe you and Larry could go together to hire a caretaker to look after both of your places while you are gone???

I actually have a chest freezer there which I keep full of.......frozen stuff, lot's of ice I make there with my icemaker and hopefully fish.
I would have to buy another to do the project. I do have an old 6cu ft freezer but it opens on the front rather than top.....which might actually make a more usable fridge.

One of the main advantages of this design is to use the horizontal style chest freezer. By having the door open up and not out, the cold air tends to stay low, inside the unit and not flow out the bottom. Ever notice all those large, chest style freezers in the supermarkets? They keep all the bagged veggies, chicken, fish, turkey and ice cream frozen all day long without a problem using the same concept.

My dad had an upright freezer and mentioned once that he noticed it used a lot more juice than his old chest style...

Frank
I am planning on going back down in early Oct. if you are still there come on by. I am putting it together up here for now, but I didn't bring my killawatt meter up with me so not sure if I can give accurate power consumption numbers. Actually I am planning a trip down in mid August to go diving, I can bring the meter back up with me then.

I am really glad you mentioned the killawatt meter Larry. I highly recommend them to anyone living off grid, or anybody else who simply wants to reduce their energy consumption. They are amazing little devices that can really teach you where/how your energy all goes as well as help you to properly size your system...

Yeah, the killawatt meters will tell you alot about your consumption on a electrical item. 2 years ago when weI first moved into jour new house, I noticed that the batteries didn't seem to recarge as I thought they should. I started checking different appliances and found that my refridgerator was using triple what it normally did in the winter. During the winter months it uses approx. 1kw a day, but in the summer it increases to 3kw a day. I tried everything I could think of, cleaning the cooling fins, putting a fan at the rear, but nothing helped. I guess it is just the nature of the beast, high ambient temps cause it to run more.
Larry

How big is the fridge and how hot does it get inside the house???

It's an 18cf Sears and is rated at 382 kw a year, and during the hottest months it can get into the mid to high 90's in the house. Not comfortable. Very humid to usually. When it is like that I run the generator all night for the A/C. When I do that, then battery charge is not a problem cause when I get up in the morn to turn off the gen my batteries are fully charged. Just an eye opener on what a refer can do with just a 20 degree rise in ambient temp.
Larry

That is hot for a refrigerator as it has to work overtime to find a way to exchange enough heat to cool down the fridge.

I put a killawatt meter on our fridge a few days ago and it has been averaging just under a KW a day the last three days. We are blessed with the cooler, Pacific side summer weather and it doesn't ever go higher than mid 70's here in the house. I intentionally designed the fridge location to go in the room under the elevated tinaco on the house. It's location is away from the summer sun so the walls are always cool and the 15 foot ceiling there really helps lift the heat away from the cooling coils.

I really do think that a chest freezer fridge conversion would be ideal for you guys...