Refrigerant vapor from the evaporator, instead of going to compressor, goes to an absorber, where it is dissolved with lean ammonia-water at low pressure.

The rich ammonia-water mixture is pumped to high pressure. As the volume handled is much lower, the pump consumes only a fraction of the compressor power.

To separate the binary mixture, now at high pressure, it is heated with steam (or other heating media). Ammonia gas separates from the mixture.

Ammonia gas is purified in a rectification column. The lean mixture left behind is cooled through solution exchangers, and returned to the absorber to dissolve more ammonia.

Purified ammonia vapor goes to the condenser where it is cooled to liquid, and returned to the evaporator to close the refrigeration cycle.

Partial stripping of incoming rich solution using the hot, lean solution leaving the stripper.  This reduces the overall steam consumption by using heat in the outgoing solution itself to pre-heat and strip vapor from the rich solution.

Hot gas from stripper exchanges heat to rich solution, substantially reducing the load on the reflux condenser and rectifier.

Absorber GAX allows cold, rich solution from the pump discharge to pick up the heat from the heat of absorption generated by the dissolution of ammonia in lean solution.  This allows partial recovery of the heat that would be otherwise lost to cooling water.