If you briefly surf the web you will find many sites that mention how the Eskimos use refrigerators to prevent food from freezing. Surely, without any scientific sources or explanation of such phenomena, simply as general information that you’re expected to believe just because you read it on the site. What do you think? Would food and water freeze or not? To answer such question, we need to figure out how does the refrigerator work in a simplified way.
A cooling device consists of 5 main components and some scientific facts:
The box: A box made out of insulating materials where the food is placed.
The compressor: It compresses the gas to facilitate its condensation (making it liquid).
The relief valve: Somehow it inverts the compressor’s work, as it changes the liquid’s flow direction to reduce the pressure and makes it evaporate.
A gas container: It’s usually filled with Ammonia due to its low boiling temperature (-30°C).
A heat exchange device: It facilitates the temperature exchange between the liquid/gas and its surrounding environment, one is placed inside the refrigerator to extract heat and another is placed outside to help cool the liquid. It usually takes a spiral shape to maximise the exchange surface.
Scientific facts: When a liquid is turned into gas, it extracts heat from its surroundings. And when a gas is turned into liquid, it induces heat into its surroundings. And low pressure reduces the boiling temperature of a liquid and vice versa.
Now we can explain the refrigerator’s working procedure:
The compressor compresses the gas which increases its temperature, then by passing through the external heat exchange device it loses heat and condensates to become to transform into a liquid state, then it passes through the relief valve which decreases the liquid’s pressure and makes it evaporate at the refrigerator’s temperature. The evaporation needs heat so it extracts it through the internal heat exchange device. The gas then goes into the compressor again and the process is repeated.
As noticed, such system can be used as a cooling unit or a heating unit, depending on the heat exchange placement.
Obviously in all refrigerator models, the heat exchange device that generate heat is placed outside of the insulation box and the ones that extract heat inside of it, which makes the refrigerator a one way (cooling) device unlike air conditioners for example.
What about the answer to our question?
The answer is “yes”, food and water will freeze, because the system will not induce any heat inside the refrigerator, and also because of the thermostat inside of the refrigerator the whole system will be shut down which turns the refrigerator into a useless expensive box.
Food and water may take longer to freeze due to the insulating materials used to make the box, but sooner or later all the heat inside the box will escape because no material is 100% insulating.
What if we disconnected the thermostat?
The refrigerator will run normally extracting heat from inside the box until the temperature reaches a point lower than the liquid’s evaporation temperature, and will then stop running.
What if we inverted the system?
If we placed the heat exchange device which induces heat inside the box it will simply turn it into a heater. A refrigerator won’t be the right name for such system.