In recent months, Cape Town has been weeks away from so-called ‘day zero’. drinking water It was to be completely depleted. It was a stark reminder of the issues affecting many parts of the world, especially the global South. In addition to reservoirs and aquifers, one of the most common solutions in extreme cases is desalination plantHowever, despite the undeniable improvement in efficiency through the use of infiltration techniques, these plants are resource intensive and too expensive for many countries. Fog harvesting systems have become an attractive option. One of the latest iterations of this type of technology is the Harp-like prototype.
With support from Virginia Tech’s Institute of Creativity, Arts, and Technology, a team of researchers adopted an approach that uses mesh to increase the efficiency of current fog collection methods that have been in use since the ’80s. With conventional nets, if the spacing is wide, water droplets can pass through the net wires without being caught, but if the spacing is too close, water droplets often cause clogging. now, biomimetic based Resolution We can solve those problems.
Coastal redwoods in California rely on fog drips for about one-third of their water intake. Their needles are knitted in a linear array, unlike the crossed wires of traditional meshes. Inspired by these structures, researchers created a kind of harp made up of hundreds of ultrafine parallel wires. Droplets slide down the wire due to gravity. The researchers then refined the system until they found the optimal wire diameter (clue: smaller is better). The latest versions of these “harps” are three times more efficient than traditional fog nets. The latest prototype contains 700 wires per square meter.This cheap, simple and efficient technology definitely improve access to drinking water in dry climates. However, there are more complex technologies that accomplish the same goal.
Other water vapor recovery technologies
In 2017, a group of researchers developed a prototype. collect water vapor in the air even in extremely dry conditions. To that end, last March, we published a paper in Nature Communications, announcing an improved version of our technology. Unlike the harp above, it uses sophisticated materials. Their approach is based on metal-organic frameworks (MOFs) composed of metal ions and organic compounds. In contrast to net-based solutions, this porous material can collect water under very dry conditions with humidity up to 10%. Also, the system does not require a pump or compressor. As a bonus, the prototype is solar powered and can operate without a power supply.
Condensation is another technique used to extract water from thin air. It works on the same principle as AC units that generate water during operation. Today, the Israeli company Water-Gen provides condensation-based equipment to military and NGOs around the world, especially in isolated areas where potable water is not available. The company’s technology, which requires an external power supply, can deliver up to 4 liters of water per kilowatt. The company also offers systems for rooftops, making the building self-sufficient in water consumption.
sauce: Science, Science Daily, Massachusetts Institute of Technology
