What is condensate subcooling and when is it desirable or problematic?

Condensate subcooling occurs when liquid condensate is cooled below saturation temperature while still in the condenser. Desirable when: preventing flash in condensate lines, reducing corrosion from dissolved gases at lower temperatures, or when cooled condensate is needed for process. Problematic when: it wastes heat transfer area that could condense more vapor, reduces condenser capacity, or excessive subcooling floods tubes reducing condensation area. In surface condensers, proper hotwell design separates subcooling from condensation zones.