Ultrasonic system boosts atmospheric water harvesting efficiency 45×
Atmospheric water harvesting holds great promise for solving global water scarcity, but it faces a major hurdle — energy inefficiency. Current systems rely on heat to evaporate trapped moisture, a slow process that consumes vast amounts of energy. Now, MIT engineers have broken this "thermal limit" with a device that uses ultrasonic waves to extract water instead.
The new method — detailed in the journal Nature Communications — replaces heat with mechanical vibrations. The research team, led by Ikra Iftekhar Shuvo, designed a piezoelectric actuator that operates at high frequencies. When a water-saturated hydrogel is placed on the device, ultrasonic waves break the weak bonds holding the water molecules to the hydrogel. The disturbance creates momentum that releases the water in liquid form, rather than vapor.
The results are significant for the field of atmospheric water harvesting. The researchers report that this vibrational method is 45 times more energy-efficient than state-of-the-art thermal systems. In tests, the device successfully extracted water in just minutes, whereas thermal desorption typically takes hours.
This technology overcomes the high energy costs and slow performance that have hindered the widespread adoption of atmospheric water harvesting. The team envisions that these actuators could be powered by small solar panels, enabling continuous, decentralized water production for arid communities and disaster zones.
People have been looking for ways to harvest water from the atmosphere, which could be a big source of water, particularly for desert regions and places where there is not even saltwater to desalinate. Now we have a way to recover water quickly and efficiently. — Svetlana Boriskina, the corresponding author of the research paper.
