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How a Propane Refrigerator Functions
When looking into how a propane refrigerator functions we go back to 1820, where English scientist Michael Faraday used liquefied ammonia to cause cooling. And our modern day civilization can credit this early start to effective cooling; as it sets the foundation for today’s refrigerators. Where an absorption ammonia refrigerator or gas refrigerator still functions on the same foundational basis as what Micheal Faraday had started with all those years ago. The mixture that these cooling systems use is a blend of anhydrous ammonia, distilled water, and hydrogen vapor.
Propane is a byproduct of natural gas processing and a byproduct of refining petroleum, being an inexpensive commercially available fuel source. Lending to the ability to be off grid and yet having the ability to power a refrigerator. Here we analyze how a propane fridge functions by using propane as an effective fuel source.
For cooling in the propane refrigerator the ammonia and water is heated by a propane flame, which is exactly why the propane refrigerator gets its name. The heat from the propane flame then causes the ammonia and the water to vaporize into a steam, traveling through the perk tube. From there the process that this steam follows is to then percolate or perked. This same perking process is very similar to the process that a coffee percolator adheres to. At this stage this is where the inner tube, also known as the perk tube, in the propane refrigerator boiler emits steam as the water bubbles, causing them to move upward.
Between these two mix components; since the ammonia is lighter than the water, the ammonia will turn into steam earlier than the water will. Which then allows for the ammonia steam to be pushed up into a condenser by the hydrogen pressure that is generated, as it is dissipating the heat, leaving the water to fall down into the outer tube; and is then pushed into the absorber tubes which then returns to the mixing tank, also known as the absorber tank.
As the ammonia steam is moving upward through the rectifier and into the condenser tubes; it then turns into a rich ammonia liquid once more. Here this rich ammonia liquid is then pushed into the top of the evaporator tubing. After it is in the evaporator, it then meets the hydrogen gas moving up through the inner tube inside the evaporator. From here this hydrogen gas absorbs the rich ammonia. As the ammonia meets this hydrogen gas here in the evaporator it then creates a chemical reaction. This chemical reaction then evaporates the ammonia, thus making it extremely cold at that point. This is what is called absorbing the heat, or better stated, removing the heat from the refrigerator box. See the image to the right to locate the propane refrigerator parts.
In the meantime, you will find that the water is then being pushed backwards to the absorber coils. At this point this is where the water drops downward to the absorber tank. While this is happening, the hydrogen gas passes upward through the absorber coils and “catches” any ammonia left in the weak water that is falling downward and carries it up to the top of the evaporation system. From there it then drops it into the outer tube of the evaporator. It then flows downward in a mist form causing it to become extremely cold. As it falls down, the rich ammonia returns to the absorber tank, also called the mixing tank. In the absorber tank the rich ammonia mixes with the weak water which allows it to continue with its cycle all over again. Constantly looping through the above processes to generate the cooling effect. With the ammonia serving as the coolant and the water, ammonia and propane serving to provide the continuous flow for the ammonia.
In summary we learned about the following:
- Ammonia will cycle through from gas to liquid and this process causes cooling effect
- Hydrogen vapor or hydrogen gas generated by the boiling water
- Distilled Water – more dense and heavier than ammonia allowing for the ammonia to boil and steam first
- Propane – used as the fuel source to generate enough heat to start the cycle and boil the water and liquid ammonia
- Generator – creating the ammonia gas
- Separator – separates the ammonia from the water
- Condenser – this is where the hot ammonia gas cools and then is condensed again to create the liquid ammonia
- Evaporator – converts the liquid ammonia to a gas thus causing the cooling effect
- Absorber tank also known as the mixing tank – where the water absorbs the ammonia gas
An ammonia absorption cooling system is a unique design specifically so that a person can operate independently by using either a propane, natural gas, or butane burner in order to heat the ammonia solution, therefore creating an ammonia refrigerator. Earlier on, there were also many cooling units that used a kerosene burner to heat the solution. This type of kerosene fueled refrigerator is still available on the market, yet its availability is in a limited capacity.
Our modern day propane refrigerator technology wouldn’t be possible without the discoveries of Michael Faraday and those early refrigeration mechanics. Our propane refrigerators of today are much improved in efficiency, capacity, fuel efficiency and functionality but we owe our thanks to these early inventors for the beautiful propane refrigerators of modern day. Our propane refrigerators provide options for hunters, homesteaders and more by allowing effective alternatives for off grid refrigeration and food storage. Check out some of our most popular propane refrigerators for your own off grid food storage needs.