What are the special considerations for vacuum condenser design?

Vacuum condenser challenges: large vapor volumes requiring large flow areas, high sensitivity to pressure drop (affects equilibrium temperature), non-condensable accumulation critical (even small amounts severely impact performance), and subcooling of condensate. Design considerations: vertical orientation common for drainage, dedicated venting zone for non-condensables, multi-zone design (desuperheating, condensing, subcooling, venting), and adequate vent condenser capacity. Steam jet ejector or vacuum pump sizing must account for air leakage plus dissolved gases from process.