This heat exchanger uses evaporation to transfer heat in one direction and drop-wise condensation to transfer heat in the other direction. In evaporation mode, liquid supplied to minichannels under a copper porous media move into the media due to capillary forces. Inside the media, the liquid evaporates, removing thermal energy. In condensation mode, liquid condenses on the top surface of the porous media to transfer heat into the media. If higher condensation performance is required, a hydrophobic, nonporous region can be added adjacent to the porous media.
The copper porous media must remain hydrophilic to ensure proper function in evaporation mode. However, contaminants during normal operation can quickly render copper surfaces hydrophobic and stop evaporation. This technology solves that problem by growing CuO/Cu2O nanostructures throughout the media, which makes the media permanently hydrophilic, even in the presence of contaminants.