Depositphotos
Researchers from Singapore have developed a fairly simple way to use falling water droplets to generation of electric power.
It is noted that the scientists performed charge separation by directing water droplets through a narrow vertical tube to create a «cork flow», and were able to effectively collect electrical charges. The electricity generated by the water droplets was enough to power 12 LEDs. The potential use of this technology on rooftops in urban areas could be a cheap alternative to hydroelectric power plants.
When two materials come into contact, the charges on their surfaces can shift, a prime example being static electricity. In the same way, water flowing over some surfaces can gain or lose electrical charge.
«Water falling through a vertical pipe generates a significant amount of electricity using a specific water flow pattern: cork flow This cork flow model can allow harvesting rain energy to generate clean and renewable electricity», — explains corresponding author of the study Sowling Soh.
A conventional hydroelectric power plant uses large volumes of water to turn turbines. However, this is only effective if there are large rivers nearby with a rapid flow. Researchers have been trying to develop a technology for smaller and much slower water flows. Charge separation makes it possible to get electricity from water if it flows through a channel, lined with a conductive surface. However, the disadvantage is that the charges accumulate only on the surface that touches the water.
To increase efficiency, the developers tried to use micro- and nanoscale channels, but they were so small that water could not flow freely through them, and pumping it would require more energy than could be obtained from such a system. The scientists developed a fairly simple setup in which water flowed from the bottom of the tower through a metal needle, creating raindrop-sized drops that fell into the opening of a 32-cm-high, 2 mm-wide vertical polymer tube. The collision of the droplets at the top of the tube created a corkscrew flow. Short columns of water alternated with air pockets. As the water flowed down into the lower part of the tube, electrical charges were separated. The water then collected in a cup under the tube, and wires placed at the top of the tube and in the cup collected electricity.
According to the developers, this system managed to convert 10% of the energy of the water flowing through the tube into electricity. Compared to a continuous flow of flowing water, the cork flow was 5 times more efficient.
Since the droplet velocities tested were much lower than those of raindrops, the researchers suggest that the system could be used to harvest electricity from rain. Another experiment allowed the scientists to make sure that the flow of water through two tubes simultaneously or sequentially generates twice as much energy.
The researchers directed the water through four tubes and the setup continuously powered 12 LEDs for 20 seconds. The researchers say that cork flow energy may be easier to set up and maintain than hydroelectric power plants, and it may be convenient for urban spaces such as rooftops.
The results of the study were published in the journal ACS Central Science
Source: SciTechDaily