Overfeed systems (re-circulation system) are those in which excess liquid is forced, mechanically or by gas pressure, through organized-flow evaporators, separated from the vapour, and returned to the evaporators. This ensures no oil in the evaporators and no liquid slugs in the compressor leading to high saving in power and maintenance.
Advantages of liquid overfeed system :
Increase in plant efficiency
Protection of compressors
Hot gas defrosting
No effects of fluctuating ambient and condensing conditions
Zero pressure drops in the evaporators / overfeed lines