Gas-type household refrigerators act on the absorption principle.Absorption means to take up or in by chemical or molecular action.Since a refrigerant(such as ammonia or Carbon Dioxide) is ultimately absorbed at one point in the system,the gas refrigerator is known as an absorption refrigerator.In gas powered refrigeration,the process begins with an apparatus known as a generator. The generator is basically a metal tank with one section having a series of coils containing steam. The steam is created via a gas flame. Strong liquid (ammonia mixed with water)flows over the coils and the heat from the steam cause it to boil.As a result of the boiling, the strong liquid gives off ammonia vapor ,which leaving the generator contains a small percentage of water and is somewhat warm. The ammonia gas enters the rectifier which is an amalgam of a heat exchanger and condenser created to purify the gas by taking away the heat and water. The heat is removed by liquid flowing though the rectifier, The cooling of the gas is what removes the water vapor.The water vapor condenses and drips back into the generator. The ammonia gas, however,proceeds to the condenser.It is here that the ammotubes, taking heat from the warm gas flowing through them.
The temperature decreases causing the ammonia gas to change phases. At the bottom of the condenser,liquid ammonia flows out. This anhydrous ammonia then passes through a cooler.The ammonia chills the cooler and the cooler then chills the unit.The ammonia then passes through the absorber.Here,the evaporated ammonia is dissolved into water.After the ammonia is absorbed,the liquid is now strong and the cycle can begin again.A pump draws off the strong liquid, and discharges it to the generator where the process starts over.