Researchers at MIT have announced they have significantly boosted the output of a machine they created able to extract drinkable water directly from the air, even in dry regions. The device uses heat from the sun or another source in its process.
The machine was first developed three years ago by the same team from MIT. The upgraded version brings the device closer to the practical water source for remote regions with limited access to water and electricity. MIT’s machine harnesses a temperature difference within the device to allow absorbent material, which collects liquid on its surface, to draw in moisture from the air at night, and release it the next day.
When the material is heated from sunlight, the difference in temperature between the heated top and shaded underside makes the water release out of the absorbent material, which condenses onto a collection plate. Originally the device used specialized materials called metal-organic frameworks, which are expensive and in limited supply.
The team has now incorporated a second stage of desorption and condensation using a readily available absorbent material. The machine’s output has been significantly increased using the new material, and its scalability as a potential widespread product is improved. The new absorbent material is called zeolite, in this case, made of a microporous iron and aluminophosphate.
The widely available material has the absorbent properties needed to provide an efficient water production system. The system can operate based on typical day-night temperature fluctuations and heating with sunlight. The sun’s heat is collected by our solar absorber plate at the top of the box-like system to warm the absorbent material, releasing the moisture the material captured overnight.
The collector plate is a copper sheet directly above and in contact with the second zeolite layer. Water collected from each side of the two layers is funneled together into a collecting tank. The new design effectively doubled the liters per day per square meter of solar collecting area, producing 0.8-liters of water daily.