70 percent of the earth’s surface is covered with water. However, the overwhelming majority of it is undrinkable as it is sea water. Scientists at the University of Illinois Urbana-Champaign (UIUC) have studied a hypothetical system that can take water vapor from the surface of the oceans and convert it into drinking water – in quantities that could supply entire cities.
water from the sea air
Water scarcity is one of humanity’s great challenges – and the situation will continue to get worse, in large part due to climate change. A potential and huge water reservoir are the oceans. However, desalination projects quickly reach their limits if you want to carry them out on a large scale.
Nature, however, is constantly desalinating water as the sun heats the surface of the oceans, evaporating water and turning it into rain. The UIUC team proposes a system that takes advantage of this principle.
The researchers suggest that a few kilometers offshore, facilities are built to capture air that is highly saturated with water vapor. This air can then be sent ashore and condensed in another facility. The resulting fresh water could then be used as drinking water, for agriculture or for various other purposes. The complete system could be powered by offshore wind turbines and land-based photovoltaic systems.
Up to 80 billion liters of water per system and year
The team evaluated a total of 14 cities worldwide for the feasibility of the proposal, including Rome, Los Angeles, Barcelona and Abu Dhabi. They investigated how much water can be obtained with this method, based on the individual situation on site. They assumed offshore structures 100 meters high and 210 meters wide.
Based on their model calculations, the researchers determined that between 37.6 and 78.3 billion liters of drinking water could be obtained in this way per plant – depending on the exact conditions on site. They then calculated how many of these plants would be needed to supply the city’s population with water, assuming a need of 300 liters per person per day. They came to the conclusion that between two and ten units would be sufficient for the cities examined.
Theoretical idea with an interesting approach
The researchers consider their approach to be an elegant solution for the drinking water supply of large cities. The systems virtually simulate the natural water cycle, with the exception that the water vapor is directed to where it is needed. In addition, the efficiency of the system even increases as climate change progresses. “The climate projections show that the oceanic vapor flux will only increase over time, providing even more fresh water supply. So, the idea we are proposing will be feasible under climate change. This provides a much needed and effective approach for adaptation to climate change, particularly to vulnerable populations living in arid and semi-arid regions of the worldsaid Afeefa Rahman, co-author of the study.
However, the idea is still very theoretical. Nevertheless, it is an interesting approach that should definitely be pursued further.
via UIUC
