Device is still in a prototype stage, but may generate enough electricity to power ambient sensors.
Jumping water droplets may actually be a new source of energy, according to one of MIT’s latest research. The announcement was actually a follow up to an earlier experiment last year that previously proved that condensing water droplets can produce an electric charge as it jumps away from a superhydrophobic surface. Recently, they have shown recently that these small amounts of electricity might actually be harnessed, and thus can be used to power devices.
The first experiment described a device consisting of metal plates coated with a very thin superhydrophobic film. When at least two droplets condense on the surface and coalesce, they jump off the surface, producing a release of surface energy that is equivalent to about 15 picowatts per square centimeter. Initially only observed as a phenomenon that produces heat transfer, the suggestion of placing another metal plate externally (parallel to the superhydrophobic layer) to collect the jumping condensations opened the possibility of harnessing the electrical energy produced as usable power.
Granted, the energy that is produced is still miniscule, and sufficient humidity required for such device to properly work, but it may be enough to power ambient systems, or passive sensors. In fact, the researchers claim that the process could easily be adjusted to produce at least 1 microwatt per square centimeter, which is already adequate enough to fully charge a mobile phone in 12 hours passively when configured into a 50-cubic centimeter shaped device.
When used in tandem with other ambient power systems, such device could provide indefinite power without the need to wire the device to any external source of energy. In addition, instead of active charging, the concept can also be used to develop a passive charging system that simply uses humidity in the air to keep handheld devices working much longer.