A new water harvester design from MIT has the ability to extract fresh water from the air to meet the daily needs of multiple people, even in regions facing water scarcity. These water harvesters typically consist of adsorbent materials that collect moisture on their surfaces. The innovative design of this new device features a series of vertical fins spaced 2 mm apart, maximizing the surface area exposed to the air. These fins are made of copper sheets embedded in copper foams and coated with a specialized zeolite material known for its water adsorption properties.
Once the fins become saturated with water after an hour, the copper sheets are heated to release the extracted moisture. When this cycle is repeated 24 times a day in arid air conditions with 30% humidity, the water harvester is estimated to produce up to 1.3 L of potable water per day per liter of the adsorbent coating used. When scaled up, this translates to 5.8 L per kilogram of material used daily, which is sufficient to cater to the daily water requirements of multiple individuals.
While there are various other water harvesters under development, this new design offers several advantages. It has a higher water collection capacity compared to many other systems, with some devices only capable of retrieving 100 ml of water per kg of material. Although a previous design from Johns Hopkins University boasted an impressive water output of 8.66 L per day per kg of material, this was tested in 70% humidity conditions. The MIT-developed harvester can operate consistently day and night, unlike other systems that accumulate water overnight and release it in the morning.
One limitation of this system is that it requires energy to release the collected water, with the base of the device needing to reach 184 °C to do so. However, the researchers suggest that waste energy or heat from other sources, such as buildings or vehicles, could be utilized to power the release process. The findings of this study were published in the journal ACS Energy Letters, illustrating the potential of this innovative water harvesting technology.