Retrofit a Freezer to Make an Ultra-Efficient Fridge

Discussion in 'General Survival and Preparedness' started by melbo, Jan 15, 2007.


  1. melbo

    melbo Hunter Gatherer Administrator Founding Member

    An off-grid experimenter in Australia, Tom Chalko, has retrofitted a chest freezer to create a fridge that uses only 100 watt-hours (0.1 kWh) per day! Why a chest freezer? Tom points out that vertical door refrigerators are inherently inefficient. As soon as you open a vertical fridge door the cold air escapes, simply because it is heavier than the warmer air in the room. When you open a chest freezer, the cool air stays inside, just because it’s heavy. Any leak or wear in a vertical door seal causes significant loss of efficiency.

    Tom took a standard chest freezer (a Vestfrost SE255), added a $40 external thermostat, then wired the freezer to turn off when the desired temperature was reached. The thermostat runs on 2 AAA batteries which last for months. The freezer runs for about 90 seconds per hour and then shuts down completely, making it not only very efficient but very quiet.
     

    Attached Files:

    melbo, Jan 15, 2007
    #1
  2. melbo

    melbo Hunter Gatherer Administrator Founding Member

    Sorry, meant retrofit a freezer to make a fridge... just edited title
     
    melbo, Jan 15, 2007
    #2
  3. Blackjack

    Blackjack Monkey+++

    Very cool (no pun intended)...... smart guy and it's just applied common sense.

    I guess you could probably increase it's efficiency even more with a little extra insulation around the sides couldn't you?

    It's not a convenient fridge, that's why it'll never catch on. People want to open the fridge and browse things on shelves right in front of them. If I had to supply my own power off-grid though, this would be one of the first to do items on my list.
     
    Blackjack, Jan 15, 2007
    #3
  4. Blackjack

    Blackjack Monkey+++

    Now that I think about it, I know there are some very efficient 12V DC chest freezers out there...... so,

    For living off-grid, I'd think that a single solar panel charging a battery would be all you would need for good refrigeration..... or would I be incorrect?
     
    Blackjack, Jan 15, 2007
    #4
  5. Quigley_Sharps

    Quigley_Sharps The Badministrator Administrator Founding Member

    Good info for you in the south,

    If you lived here we would just hike up the mnts to the Glaciers and cut blocks of ice for your Ice box once a month.
     
    Quigley_Sharps, Jan 15, 2007
    #5
  6. Seacowboys

    Seacowboys Senior Member Founding Member

    the start and stop of the compressor has to shorten the life considerably, I would imagine. And the shelving is kinda hard to get to the lettuce on bottom[dunno]
     
    Seacowboys, Jan 15, 2007
    #6
  7. Blackjack

    Blackjack Monkey+++

    Doesn't the compressor start/stop all the time anyway only more often? I dunno, but I thought that's how it worked.
     
    Blackjack, Jan 15, 2007
    #7
  8. Seawolf1090

    Seawolf1090 Retired Curmudgeonly IT Monkey Founding Member

    A very interesting idea. I have used a programmable timer to control my fridge - only needs to run a few hours a day, IF it isn't opened very often. Saves electricity - especially doing the same with the water heater.
    The fridge in my fairly new house is a cheapo though - when it starts showing it's age, I'll replace it with a chest freezer modded this way. I have the room in my kitchen, and I can use the old fridge as a storage locker.
     
    Seawolf1090, Jan 16, 2007
    #8
  9. Blackjack

    Blackjack Monkey+++


    If your married you'll have a tough time gettin that one past her. Chest fridge would be pretty inconvenient.
     
    Blackjack, Jan 16, 2007
    #9
  10. monkeyman

    monkeyman Monkey+++ Moderator Emeritus Founding Member

    A lot of the inconvenience can be overcome. Just get boxes, like the milk crates, and put stuff in them and stack them in the chest. You can arange either like things together like all the meats in one, condements in another and so on or knowing your comon combos, have 1 crate that has all the sandwich stuff, one with the breakfast stuff and so on. Then you just grab the crate you need and can get to the lower ones pretty easy (where the least used stuff is kept) as well.

    As far as adding insulation, it helps out a lot IF done right. You have to make sure NOT to insulate the compressor or coil areas where it expells the heat in with the rest of the box or you will hold heat in and be working against yourself.
     
    monkeyman, Jan 17, 2007
    #10
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