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Researchers Explain Why Sunlight Evaporates Water Faster Than Other Heat Sources — And The Secret Is In The Electric Field
A group of researchers from North Carolina State University in the United States may have solved an ancient mystery: why sunlight is more effective than other energy sources at evaporating water.
The discovery has important implications for sectors such as energy generation, water purification, and industrial steam production.
Sunlight Is Different
Professor Saqlain Raza summarizes the main point: “It is well established that the Sun is exceptionally efficient at making water evaporate — more efficient than heating water on the stove, for example.” But, according to him, no one really knew the reason for this until now.
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To better understand the process, the researchers used computer simulations. With them, it was possible to alter various parameters and analyze how each one affects water evaporation.
What caught the team’s attention was the role of the electric field present in sunlight. According to Jun Liu, a member of the research, “light is an electromagnetic wave that consists, in part, of an oscillating electric field.” And this detail made all the difference.
Without The Electric Field, Water Evaporates Slowly
The simulations showed that, by removing the electric field from sunlight, water evaporation slowed down.
On the other hand, when the electric field was present, the process was much faster. Additionally, the stronger the electric field, the more efficient the evaporation.
According to Liu, it is this electric field that makes the difference between simply heating water and using sunlight. Heat alone does not yield the same result.
How The Electric Field Affects Water Molecules
The simulations also revealed how the electric field directly influences water molecules.
According to Professor Raza, evaporation can occur in two ways: either water releases individual molecules, or it releases clusters, which are groups of interconnected molecules.
The essential point is that these clusters can also separate from the liquid water. Moreover, it requires no more energy to evaporate a cluster than a single molecule.
“We found that the oscillating electric field is particularly effective at breaking apart water clusters,” Liu explained. This makes the process much more efficient, as several molecules can evaporate at once.
Faster Evaporation With Hydrogels
The team tested the theory in two scenarios: one with pure water and another with a hydrogel. In the first, few water clusters were found near the surface.
In the second, with hydrogel, clusters formed in greater numbers where the liquid touched the material.
This facilitated the action of the electric field. With more clusters available to be broken, evaporation happened more quickly.
The presence of the electric field from sunlight may, therefore, be the key to understanding why the Sun is so effective at evaporating water.
The discovery, based on detailed simulations, points to practical applications in various industrial and environmental areas.
With information from Inovação Tecnológica.
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