As always, science continues to impress me. Scientists in Grenoble, France, have discovered a way to harvest energy from falling raindrops that can be used to power electronic devices. The new system catches the mechanical energy from the impact of a falling raindrop and uses it to convert the energy to electricity.
But first, a mechanical-electric model measures the impact of the raindrops. The physics of a raindrop impacting a surface is actually pretty easy to understand. The speed that a raindrop falls at will determine the amount of energy produced upon hitting the ground. When it hits the surface, the raindrop produces an inelastic shock, and the amount of energy generated from the impact is then measured by the mechanical-electric model.
Then, scientists capture the energy by using a PVDF (polyvinylidene fluoride) polymer, which converts the energy. When a raindrop impacts the PVDF, the polymer begins to vibrate. Electrodes embedded in the polymer are then used to recover the electrical charges generated by the vibration.
The new system works with raindrops ranging in diameter from 1 to 5 mm. A micro-pump was used to create the raindrops, although the scientists’ next step is to measure the impact from Mother Nature herself. The model also controlled drop size, frequency, and height as drops of water fell and impacted a piezoelectric material at the base.
“A good alternative to power systems in raining outdoor environments where solar energy is difficult to exploit,” said Thomas Jager explained in the latest issue of Smart Materials and Structures. “For example, we intend to develop remote sensor nodes in cooling towers, but abandoned sensor networks are also one of the foreseen applications for this type of system.”
Jager and his team now plan on developing a way to store the electrical power to provide a steady current for practical use.