Right now, in current condenser designs, water congeals in a thin film on the condenserâ(TM)s surface. Before new water droplets can form there, this water must fall away from the surface and be conveyed back over the boiler. âoeTo have the most efficient condensing surface, you want to remove the droplets as early as possible,â says Dr. Nenad Miljkovic, postdoctoral associate at MIT and co-author on âoeElectrostatic charging of jumping dropletsâ.
When a water droplet forms on a sheet of metal coated with a superhydrophobe, the droplet can camp there only so long as it does not merge with another droplet. As soon as it weds with another droplet, the energy produced is so great that the two will âoejumpâ away from that surface, as if in urgent deference to the surfaceâ(TM)s severe water phobia. Scientists have proposed that this âoejumpingâ could be incorporated into power plant design. But, in prototypes, this âoejumpingâ design is not as efficient as engineers believe it could be. Some of the droplets will just fall back to the condenserâ(TM)s surface, recoating it and slowing the process down.
A newly discovered component to the âoejumpingâ process might allow scientists to eliminate this fall back. In an accidental find, the MIT team found that droplets donâ(TM)t just spring from the surface â" they also rebound from each other, because an electrical charge forms on the droplets as they flee the hydrophobic surface. So, if a charge is applied to the condenser system, the water droplets can be electrically prevented from returning to the surface, he said. âoeIf you utilize the fact that these droplets are charged, you can now create an external electric field, which can attract the droplets away from the surface, and make sure they donâ(TM)t return,â says Miljkovic.
At the moment, these are lab results, but the scientists say that they are confident that the charged âoejumpingâ can be reproduced on a macro-scale suitable for commercial purposes â" those possible applications include not just use in power plants, but also in de-icing technologies for airplanes and wind turbines.