Heat pipes are reliable and passive heat transport devices, but their heat transport capacity degrades rapidly for long working lengths due to insufficient capillary pressure generated by the wick.
Our recent efforts are targeted at developing new planar heat pipe that can transport kilowatts of heat over meter long distances. The enabling technology is the replacement of the heat pipe wick with electrowetting-based pumping. The electrowetting heat pipe (EHP) uses electrowetting pumping of the condensate to the evaporator in the form of discrete droplets. This innovation can overcome the capillary limit to heat transport capacity and enable slender, planar long heat pipes for high heat load energy-related applications.