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My non-electric refrigerator operates along similar lines but uses a propane burner to dissociate ammonia from water in a continuous cycle. Devices such as this

My non-electric refrigerator operates along similar lines but uses a propane burner to dissociate ammonia from water in a continuous cycle. Devices such as this can operate on many different heat sources including kerosine. Absorption refrigerators have been available for over a century but they are neither cheap nor inherently safe. https://en.wikipedia.org/wiki/Absorption_refrigerator#Single_pressure_absorption_refrigeration https://en.wikipedia.org/wiki/Absorption_refrigerator#Single... My next off-grid refrigerator will be solar-electric with a high efficiency compressor. Even factoring in the cost of additional solar panels and a storage battery it will be cheaper to purchase and certainly cheaper to run.

nightbrawler 4y ago
At my offgrid cabin I converted a $300 chest freezer to a fridge by using an external thermostat that toggles power off/on based on temp. I have it turn on at 37 degrees and turn off at 35. It uses such little power that it's not even a factor for my small solar setup.
- ilovetux 4y ago
  Chest freezers are great because they dont have a front-facing door which lets all the cold fall right out.
  - nightbrawler 4y ago
    Indeed. Not as easy to organize as one with a front facing door, but we keep stuff organized in milk crates and it's worked great for our family for many years now.
hinoki 4y ago
What’s not safe about them? I thought that absorption refrigerators were developed to be safer than existing refrigerators, before non-toxic working fluids were discovered. Einstein-Szilárd fridge. Yes, that Einstein and that Szilárd. https://en.m.wikipedia.org/wiki/Einstein_refrigerator https://en.m.wikipedia.org/wiki/Einstein_refrigerator
- deleted 4y ago
  [deleted]
- elil17 4y ago
  Ammonia is a very dangerous chemical. From a thermodynamic and environmental perspective it's one of the best refrigerants for many applications but we can't use it in residential buildings because you'll die if you breath it in. The E-S refrigerator was used because it's high reliability made it safe for certain critical applications, not because it used a safe working gas.
  - gumby 4y ago
    > Ammonia is a very dangerous chemical. From a thermodynamic and environmental perspective it's one of the best refrigerants for many applications but we can't use it in residential buildings because you'll die if you breath it in. FWIW I’ve only seen propane/ammonia cycle fridges inside residences so I don’t understand what you mean by “can’t use it in residential buildings”
    - sandworm101 4y ago
      Scale. A small personal fridge in an RV or small apartment isn't a big deal. But a system big enough to power comercial refrigeration or air conditioning to a residential building will involve enough coolant that any leak would be serious problem.
      - namibj 4y ago
        Yeah, but indirect (with e.g. water/glycol between the condenser and the indoor air handler) systems can be combined with scrubber tanks (basically just water+baffles, I think) that the blow-off from a leak or a pressure relief valve is forced through, in order to contain most of the ammonia.
      - KennyBlanken 4y ago
        Many supermarkets use ammonia refrigeration. Many food warehouses and packing plants use it as well- resulting in incidents fairly often. It's still used.

nightbrawler 4y ago

At my offgrid cabin I converted a $300 chest freezer to a fridge by using an external thermostat that toggles power off/on based on temp. I have it turn on at 37 degrees and turn off at 35. It uses such little power that it's not even a factor for my small solar setup.

ilovetux 4y ago
Chest freezers are great because they dont have a front-facing door which lets all the cold fall right out.
- nightbrawler 4y ago
  Indeed. Not as easy to organize as one with a front facing door, but we keep stuff organized in milk crates and it's worked great for our family for many years now.

hinoki 4y ago

What’s not safe about them? I thought that absorption refrigerators were developed to be safer than existing refrigerators, before non-toxic working fluids were discovered. Einstein-Szilárd fridge. Yes, that Einstein and that Szilárd. https://en.m.wikipedia.org/wiki/Einstein_refrigerator https://en.m.wikipedia.org/wiki/Einstein_refrigerator

deleted 4y ago
[deleted]
elil17 4y ago
Ammonia is a very dangerous chemical. From a thermodynamic and environmental perspective it's one of the best refrigerants for many applications but we can't use it in residential buildings because you'll die if you breath it in. The E-S refrigerator was used because it's high reliability made it safe for certain critical applications, not because it used a safe working gas.
- gumby 4y ago
  > Ammonia is a very dangerous chemical. From a thermodynamic and environmental perspective it's one of the best refrigerants for many applications but we can't use it in residential buildings because you'll die if you breath it in. FWIW I’ve only seen propane/ammonia cycle fridges inside residences so I don’t understand what you mean by “can’t use it in residential buildings”
  - sandworm101 4y ago
    Scale. A small personal fridge in an RV or small apartment isn't a big deal. But a system big enough to power comercial refrigeration or air conditioning to a residential building will involve enough coolant that any leak would be serious problem.
    - namibj 4y ago
      Yeah, but indirect (with e.g. water/glycol between the condenser and the indoor air handler) systems can be combined with scrubber tanks (basically just water+baffles, I think) that the blow-off from a leak or a pressure relief valve is forced through, in order to contain most of the ammonia.
    - KennyBlanken 4y ago
      Many supermarkets use ammonia refrigeration. Many food warehouses and packing plants use it as well- resulting in incidents fairly often. It's still used.