Explained: How Swiss researchers drew clean drinking water out of thin air with no energy input

Access to clean or potable water is a major concern for many areas. Because increasing levels of pollutionglobal warming and sea level rise, access clean drinking water it is becoming extremely difficult for many communities, especially in developing and underdeveloped countries.

To counter that, a team of Swiss scientists and engineers has come up with a way to extract clean drinking water from thin air. The best thing about the new method that these engineers have devised is that it does not require any input of energy or electricity to work. Communities living near the sea can desalinate seawater and make it drinkable. However, this process requires a lot of energy. Areas away from the sea or any major body of water depend on the atmosphere and local water bodies, which are drying up. If we are talking about a rich, developed country, they condense atmospheric moisture through cooling and create artificial rain, which again is an electricity-intensive solution. In developing or underdeveloped countries, the only option is to trust the rains, or in passive technologies such as the use of dew collector sheets or water harvesting, both of which come with their own set of challenges. Researchers at ETH Zurich have developed a technology that, for the first time, allows them to collect water 24 hours a day, without energy input, even under the scorching sun. The new device is essentially made up of a glass panel with a special coating, which reflects solar radiation and also radiates its own heat through the atmosphere into outer space. It is capable of cooling down to 15 degrees Celsius below ambient temperature. The water vapor under the glass panel then condenses into water, which is then collected in tanks. The scientists coated the glass with specially designed layers of polymer and silver. This coating allows the panel to emit infrared radiation in a specific wavelength window into outer space, without absorption by the atmosphere or reflection on the panel. Because of this, this method also does not contribute to global warming, unlike most other condensation-based dewatering solutions. Another key element of the device is the cone-shaped radiation shield. It greatly deflects heat radiation from the atmosphere and shields the panel from incoming solar radiation. This allows the device to radiate the aforementioned heat to the outside, and thus self-cool, completely passively. The scientists were able to show that, under ideal conditions, they could collect up to 53 milliliters of water per square meter of panel surface per hour. While it may seem like very little, the theoretical limit that most other solar-based water extraction systems aim for, which incidentally contributes to the greenhouse effect and global warming, is 60 milliliters. Via: First Post


Table of Contents