Gas and Propane Refrigerators
If you own an RV or use a refrigerator where electricity is not available, chances are you have a gas or propane powered refrigerator. These refrigerators are interesting because they have no moving parts and use gas or propane as their primary source of energy. They use heat in the form of burning propane to produce the cold inside the refrigerator.
A gas refrigerator uses ammonia as the coolant and it uses water, ammonia and hydrogen gas to create a continuous cycle of expansion and compression of the ammonia. The propane refrigerator has five main parts:
- Generator - generates ammonia gas
- Separator - separates ammonia gas from water
- Condenser - hot ammonia gas is cooled and condensed to create liquid ammonia
- Evaporator - liquid ammonia evaporates to create cold temperatures inside the refrigerator
- Absorber - absorbs the ammonia gas in water
The cycle works like this: Heat is applied to the generator from burning propane.
The generator contains a solution of ammonia and water. The propane flame raises the temperature of the amonia solution to its boiling point.
The boiling amonia solution flows to the separator.
The separator separates the water from the ammonia gas.
The ammonia gas flows upward to the condenser. The condenser is composed of metal coils and fins that allow heat to escape from the ammonia gas and condense into a liquid.
The liquid ammonia flows to the evaporator and mixes with hydrogen gas. It evaporates (expands) producing cold temperatures inside the refrigerator.
The ammonia and hydrogen gases flow to the absorber. The water that has collected in the separator mixes with the ammonia and hydrogen gases.
The ammonia forms a solution with the water and releases the hydrogen gas, which flows back to the evaporator. The ammonia-and-water solution flows toward the generator to repeat the cycle.