A new method of extracting drinking water from the atmosphere has been proposed by Israeli scientists. This method not only offers a genuine alternative to seawater desalination, but it also requires significantly less energy than comparable methods. The atmosphere contains approximately 13,000 cubic kilometers of water, which is roughly equivalent to the amount of freshwater on Earth, excluding glaciers and ice at the poles. This water could provide many people with vital drinking water. However, extracting water directly from the humid air requires a lot of energy for cooling. The new method proposed by the Israeli scientists involves condensing water only from pure water vapor, rather than from humid air. Initial calculations show that this method requires up to 65% less energy.
David Broday from the Israel Institute of Technology Technion in Haifa explains that “humidity is a significant source of drinking water that could be tapped into virtually anywhere on the planet.” Extracting drinking water from the atmosphere is particularly interesting for dry regions far from the sea, as it provides access to clean water. To keep the energy required for cooling as low as possible, Broday and his team plan to remove the water vapor from the air beforehand using a drying agent. The calculations show that this approach could be successful, requiring only one-third of a kilowatt-hour of electricity for cooling per liter of drinking water. The scientists assume a minimum of 30% humidity in their calculations. Their method involves blowing this air into a concentrated lithium chloride solution, which absorbs the water as an excellent drying agent. When this solution is subsequently heated by sunlight, it releases some of the absorbed water as pure water vapor. The cooling system would then only need to cool the water vapor below the dew point. According to calculations, this method reduces energy requirements by around two-thirds compared to direct cooling of humid air.
With the data already collected, a pilot plant for extracting drinking water from humid air could be constructed. Experiments with the plant would then need to show whether the required energy consumption actually matches the calculations. This new method of extracting drinking water from the atmosphere offers a promising solution for providing clean water to people in dry regions.
