Connect with us

Hi, what are you looking for?

CleanTechnica

Clean Power

Jumping Water Droplets — Charged Droplets Discovery May Lead To New Power Generation Methods, And More Efficient Power Plants

In a new — and rather unexpected — finding, researchers at MIT have discovered that, under certain conditions, water droplets can actually “jump” away from a surface, rather than simply slowly slide off of one via gravity. Specifically, when tiny water droplets condense and form on a superhydrophobic surface, it creates a situation where, if any two of these droplets coalesce, then the newly formed droplet actually spontaneously “leaps” away from the surface — the “leap” being the result of a release of excess surface energy, and as the result of a net positive electrical charge forming on the droplets as they jumped away from the surface.

The researchers think that this new discovery could be utilized to improve the efficiency of conventional power plants, and also to develop entirely new ways of harnessing energy from the atmosphere.

Images such as this, showing droplets being shed from a superhydrophobic surface (light band at center), revealed the charging of the droplets. Image Credit: Nenad Miljkovic and Daniel Preston

Images such as this, showing droplets being shed from a superhydrophobic surface (light band at center), revealed the charging of the droplets.
Image Credit: Nenad Miljkovic and Daniel Preston

MIT explains the findings in more detail:

In order to understand the reason for the repulsion between jumping droplets after they leave the surface, the researchers performed a series of experiments using a charged electrode. Sure enough, when the electrode had a positive charge, droplets were repelled by it as well as by each other; when it had a negative charge, the droplets were drawn toward it. This established that the effect was caused by a net positive electrical charge forming on the droplets as they jumped away from the surface.

The charging process takes place because as droplets form on a surface they naturally form an electric double layer — a layer of paired positive and negative charges — on their surfaces. When neighboring drops coalesce, which leads to their jumping from the surface, that process happens so fast that the charge separates. It leaves a bit of charge on the droplet, and the rest on the surface.

The initial finding that droplets could jump from a condenser surface — a component at the heart of most of the world’s electricity-generating power plants — provided a mechanism for enhancing the efficiency of heat transfer on those condensers, and thus improving power plants’ overall efficiency. The new finding now provides a way of enhancing that efficiency even more: By applying the appropriate charge to a nearby metal plate, jumping droplets can be pulled away from the surface, reducing the likelihood of their being pushed back onto the condenser either by gravity or by the drag created by the flow of the surrounding vapor toward the surface.


“Now we can use an external electric field to mitigate” the tendency of the droplets to gravitate to the condenser, “and enhance the heat transfer,” states researcher and MIT postdoc Nenad Miljkovic.

Interesting findings, especially when you consider some of the possibilities… As Miljkovic writes: “By placing two parallel metal plates out in the open, with one surface that has droplets jumping, and another that collects them … you could generate some power just from condensation from the ambient air. All that would be needed is a way of keeping the condenser surface cool, such as water from a nearby lake or river. You just need a cold surface in a moist environment.” Miljkovic and team are now working on demonstrating this concept.

The new research was just published in the journal Nature Communications.

 
 
 
Appreciate CleanTechnica’s originality and cleantech news coverage? Consider becoming a CleanTechnica Member, Supporter, Technician, or Ambassador — or a patron on Patreon.
 

Don't want to miss a cleantech story? Sign up for daily news updates from CleanTechnica on email. Or follow us on Google News!
 

Have a tip for CleanTechnica, want to advertise, or want to suggest a guest for our CleanTech Talk podcast? Contact us here.
Advertisement
 
Written By

James Ayre's background is predominantly in geopolitics and history, but he has an obsessive interest in pretty much everything. After an early life spent in the Imperial Free City of Dortmund, James followed the river Ruhr to Cofbuokheim, where he attended the University of Astnide. And where he also briefly considered entering the coal mining business. He currently writes for a living, on a broad variety of subjects, ranging from science, to politics, to military history, to renewable energy.

Comments

You May Also Like

Consumer Technology

Have you ever sat around and wondered how 2D materials expand? Me neither, but if you have, then a team of researchers may have...

Clean Power

Deep geothermal technology can harness the heat stored beneath the Earth's crust to make abundant zero emissions energy.

Batteries

Researchers at MIT and other universities have created an aluminum-sulfur battery that is cheaper and more effective than lithium-ion.

Clean Transport

Earlier this month, we ran an article about the Formula Sun Grand Prix, a track race that also serves as the qualifier for the...

Copyright © 2022 CleanTechnica. The content produced by this site is for entertainment purposes only. Opinions and comments published on this site may not be sanctioned by and do not necessarily represent the views of CleanTechnica, its owners, sponsors, affiliates, or subsidiaries.