Two billion people lack access to safe drinking water, and traditional desalination consumes enormous amounts of energy. A new Korean device changes the game: 3,4 litres of fresh water per hour with zero electricity consumption. Solar conversion efficiency reaches 94%, while traditional systems stop at 30-40%. Tested for two weeks in extreme conditions, it maintained consistent performance even with salinity twice that of the sea. The numbers speak for themselves: the solution to the global water crisis may be closer than we imagine.
The perovskite that turns the sun into fresh water
The device developed by researchers at theUNIST University In South Korea, they use a material that sounds familiar to those who follow solar technologies: perovskite. But not the one used in photovoltaic panels. Here, we're talking about La0.7Sr0.3MnO3, a perovskite oxide that converts sunlight directly into heat through the formation of intraband trap states. The material facilitates the nonradiative recombination of electrons and photoexcitation, releasing energy in the form of heat through thermalization.
Translated from scientific jargon: this material heats up very well when the sun shines on it. And when it heats up, it evaporates seawater extremely efficiently. The study published in Advanced Energy Materials demonstrates that the system achieves a impressive solar evaporation rate of 3,40 kg m⁻² h⁻¹ .
The device far outperforms traditional solar evaporation systems, which typically achieve only 0,3-0,4 kg/m²/h under natural sunlight. An improvement of almost ten times that transforms a niche technology into a potentially scalable solution.
The salt problem solved with intelligent design
Solar desalination has always had an Achilles heel: salt builds up on photothermal materials, reducing efficiency and causing what researchers call "fouling." It's like limescale forming on faucets, only worse. The Korean team solved the problem with an inverted L-shaped design that creates unidirectional fluid flow.
The system establishes a salt gradient that pushes salt toward the edges of the photothermal material, significantly reducing clogging and light shielding. As the research team explains: “By combining La0.7Sr0.3MnO3 with this innovative design, we achieve a impressive solar evaporation rate of 3,40 kg m⁻² h⁻¹ under one sun, while ensuring strong anti-fouling capabilities in complex environments.”
Endurance tests prove it: two weeks of stable operation in highly concentrated saline solutions with a 20% salt content, exceeding the salinity of normal seawater. The device continues to operate without any loss of performance.
The global rush for fresh water
The timing of this discovery is not coincidental. According to FAO estimatesBy 2025, approximately 1,8 billion people will live in areas affected by "absolute water scarcity." Two-thirds of the world's population could face "water stress."
The desalination market is growing accordingly. Global Water Intelligence Oxford estimates that the overall desalination market will reach $2025 billion by 12, an 11% jump from its current value.
The substantial difference The difference between this system and traditional ones lies in operating costs. Conventional reverse osmosis desalination produces water at a cost of $0,45–$1,72 per cubic meter, but requires enormous amounts of electricity. The Korean solar system completely eliminates energy costs.
Italy and desalination: a difficult love
In our country, desalination still represents only 0,1% of total water withdrawal, according to Istat data. And yet climate conditions are changing rapidly: Between 6% and 15% of the Italian population already lives in drought-vulnerable areas.
Projects like the one by the Padua-based company Genius Watter, which has invested €100 million over five years in photovoltaic desalination systems, is showing growing interest. But the Korean technology could represent a qualitative leap: no expensive solar panels, no batteries, no complex maintenance.
As Professor points out Ji-Hyun Jang, UNIST project leader: “By integrating an innovative structural design with a perovskite-based photothermal material, we have developed a low-cost, electricity-free device capable of producing 3,4 kg of fresh water per hour.”
The future floats on salt water
The researchers suggest that a robust evaporator system could be designed for the future by incorporating a large number of inverted L-shaped solar evaporators into a single, large-area module. The idea is as simple as it is effective: floating modules that process seawater directly on-site.
As we have seen with other similar projectsSolar desalination is becoming increasingly practical and accessible. But the Korean system takes a significant step forward: it eliminates complexity while maintaining efficiency.
3,4 liters per hour may seem small. But multiplied by thousands of devices distributed along the world's coasts, it could mean the difference between thirst and abundance. The sun rising every morning could truly be the answer to the global water crisis. You just need to know how to capture it properly.
