How a Propane Refrigerator Functions
An absorption ammonia refrigerator or gas refrigerator still functions on the same basis as Micheal Faraday had started with. The mixture that these cooling systems use is a mixture of anhydrous ammonia, distilled water, and hydrogen vapor.
Here we analyze how a propane fridge functions. The ammonia and water is heated by a propane flame [which is why it is called a propane refrigerator] thus causing it to vaporize into a steam through the perk tube. The process that this steam is being perked, is similar to a coffee percolator. The inner tube [perk tube] in the boiler emits steam & water bubbles moving upward. Since the ammonia is lighter than water, the ammonia will turn into steam sooner then the water will. This ammonia steam is pushed up into a condenser by the hydrogen pressure while the water falls down into the outer tube and is pushed into the absorber tubes which then returns to the mixing tank [absorber tank].
As the ammonia steam is moving upward through the rectifier and on into the condenser tubes it again turns into a rich ammonia liquid. This rich ammonia liquid is pushed into the top of the evaporator tubing. After it is in the evaporator it meets the hydrogen gas moving up through the inner tube inside the evaporator. This hydrogen gas absorbs the rich ammonia. As the ammonia meets this hydrogen gas in the evaporator it creates a chemical reaction . This reaction 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 mean time, the water is then being pushed backwards to the absorber coils and 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 and 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 [mixing tank] and mixes with the weak water which allows it to continue with it’s cycle all over again.
An ammonia absorption cooling system is a unique design invented so that a person can operate independently by using either a propane , natural gas, or butane burner to heat the ammonia solution therefore creating and ammonia refrigerator. Earlier on, there were also many cooling units that used a kerosene burner to heat the solution. This type of refrigerator is still available on the market, yet is much more limited in supply. Read more….