What are two types of condensation?

Condensation can be broadly categorized into two main types depending on the physical nature of the surface where the vapor liquefies and how the liquid interacts with that surface. The first type is film condensation, which occurs when the condensing liquid wets the solid surface completely, forming a continuous, uniform film of liquid that flows downward under the influence of gravity. This type typically happens on clean, hydrophilic surfaces and provides an efficient medium for heat transfer because the liquid film acts less as an isolated barrier. The second type is dropwise condensation, which occurs when the vapor condenses into discrete, individual droplets rather than a continuous sheet, typically happening on hydrophobic or oily surfaces where water beads up. Dropwise condensation is thermally much more efficient than film condensation because a large portion of the solid surface remains directly exposed to the vapor, allowing rapid heat transfer to take place before the droplets grow heavy enough to roll off.