The absorption process in the lnP / 1/T diagram
The ammonia evaporates at low temperature and low pressure in the evaporator (EV) and flow to the absorber (AB) where it is dissolved by a water/ammonia solution. This solution is pumped to the high pressure level in the desorber (DE), where the ammonia is separated again from the liquid solution. This is accomplished by heating up the solution to the boiling-point so the ammonia evaporates out of the solution. The vapour is subsequently liquefied in the condenser (CO). The heat which is needed in the desorber comes e.g. from the flue gases of a co-generation unit. The efficiency is increased by two additional heat exchangers, the solution heat exchanger (SHE) and the refrigerant cooler (RC).
The following diagram is indicative only. It can not be used to design a process.