This is where the absorption of the ammonia vapor by the ammonia water solution is taking place. The solution is poor in ammonia and gets enriched by the ammonia vapor coming from the evaporator. This absorption reaction is exothermic, the heat generated must be rejected in order to maintain the performance of the absorber. Generally, this heat is moved from the absorber via a heat exchanger to a cooling tower which dissipates it to the ambient temperature. In some configurations the solution could flow directly into a cooling tower. The strong solution is then pumped to the desorber.


This component, also called generator, does the opposite of the absorber. The desorber is heated in order to boil out the solution and release the ammonia vapor. Ammonia absorption plants are typically driven by hot water or steam but with an adapted design, it is possible to get the required heat directly from any hot gases or liquids. The lower the desired refrigeration temperature is, the higher the required heat at the desorber must be.