How does a Propane Refrigerator Work?
It's a system called "Continuous Absorption".
The Continuous Absorption type of cooling unit is operated by the application of a limited amount of heat, which is provided by propane. Unlike a conventional electric refrigerator, no moving parts are required on a propane refrigerator.
The unit consists of four parts:
The Cooling Process
- The required heat is provided by a burner, which is fitted under the central tube.
- The refrigerator is charged with a specific combination and quantity of ammonia, water and hydrogen at a pressure sufficient to condense ammonia at the ambient (room) temperature for which the unit was designed.
- When heat is supplied to the boiler system, bubbles of ammonia gas are produced which rise and carry with them, quantities of weak ammonia solution through a siphon pump. This weak solution passes into a tube, while the ammonia vapour passes into a vapour pipe and on to a water seperator. Here, any vapour is condensed and is retuned to the boiler system. What's left is dry ammonia vapour which passes on to the condenser. Air circulating over the fins of the condenser removes heat from the ammonia vapour causing it to condense to liquid ammonia. From this stage, the liquid ammonia flows to an evaporator.
- The evaporator is supplied with hydrogen. The hydrogen passes accross the surface of the ammonia and lowers the ammonia vapour pressure sufficiently to allow the liquid ammonia to evaporate. The evaporation of the ammonia extracts heat from the evaporator. This, in turn, extracts heat from the food storage area, lowering the temperature inside the refrigerator.
- The mixture of ammonia and hydrogen vapour passes from the evaporator to an absorber. When a continuous trickle of weak ammonia solution enters the upper portion of the absorber by gravity. Flowing down through the absorber, this weak solution comes in contact with the mixed ammonia and hydrogen gases, which readily absorbs the ammonia mixture. This leaves the hydrogen free to rise through the absorber coil and return to the evaporator. The hydrogen continues to circulate continuously between the absorber and the evaporator.
- The strong ammonia solution produced in the absorber flows down to the absorber vessel and from there to the boiler system, completing the cycle of operation.
- Heat is generated in the absorber by the process of absorption. This heat must be dissipated into the surrounding air. Heat must also be dissipated from the condenser in order to cool the ammonia vapour sufficiently for it to liquify. Free air ciruculation is neccessary over the absorber and condenser.
The whole unit operates by the heat applied to the boiler system. It is essential that this heat is properly applied and maintained within the required limits. Questions? Contact Us