  Vapor condensation is extensively used in applications that demand the
exchange of a substantial amount of heat energy or the vapor-liquid phase
conversion. In conventional condensers, the condensate removal from a subcooled
surface is caused by gravity force. This restricts the use of such condensers
in space applications or in horizontal orientations. The current study
demonstrates proof-of-concept of a novel plate-type condenser platform for
passively removing condensate from a horizontally oriented surface to the
surrounded wicking reservoir without gravity. The condensing surface is
engineered with patterned wettabilities, which enables the continuous migration
of condensate from the inner region of the condenser surface to the side edges
via surface energy gradient. The surrounding wicking reservoir facilitates the
continuous absorption of condensate from the side edges. The condensation
dynamics on different substrates with patterned wettabilities are investigated,
and their condensation heat transfer performance is compared. The continuous
migration of condensate drops from a superhydrophobic to a superhydrophilic
area can rejuvenate the nucleation sites in the superhydrophobic area,
resulting in increased heat transport. We can use the condenser design with
engineered wettability mentioned above for temperature and humidity management
applications in space.
