Access to clean and safe drinking water is becoming more and more of an issue for millions of people around the globe. Scientists from the University of South Australia devised an affordable technology to solve this issue.

Water is one of the most essential resources on Earth - Image Credit: Tim UR via iStock/Getty Images - HDR tune by Universal-Sci

Right now, nearly 1.5 billion people on this planet live in regions with high water vulnerability. Meaning that the extent to which access to water is sensitive to disruption is large. It is expected that his number will grow in the future due to climate change, growing populations, and contamination.

A group of scientists at the Future Industries Institute affiliated with the University of South Australia aims to mitigate or perhaps even completely solve this issue in the future. With their efforts, they have refined a procedure to derive fresh water from polluted water, brackish water, or regular seawater through extremely efficient solar evaporation. Per day it can generate a sufficient amount of fresh drinking water to accommodate a family of four people from just a single square meter of source water.

According to Haolan Xu (head of the research team), solar evaporation as a method to derive fresh water from contaminated water has gained a lot of awareness in past years. However, up until now, methods used have been inadequate due to a lack of efficiency resulting from heat loss.

Xu: "We have overcome those inefficiencies, and our technology can now deliver enough fresh water to support many practical needs at a fraction of the cost of existing technologies like reverse osmosis." Reverse osmosis is a method to clean water. It uses a partly penetrable layer to separate undesired molecules, ions, and bigger particles from drinkable water.

At the core of the system is a very effective photothermal structure that rests on the surface of a water source and transforms sunlight into heat, directing energy accurately on the surface to evaporate the uppermost portion of the liquid in a swift manner.

Xu explains that, in the past, several of the experimental photothermal evaporators were two-dimensional, composed of a flat surface, wasting up to 20% of the radiant heat from the sun into its surroundings.

An artist impression of a photothermal evaporator as design by the Future Industries Institute research team - Image Credit: University of South Australia

By comparison, the technology developed by the Future Industries Institute team consists of a 3D, fin-shaped, heat-sink-like evaporator. Not only does it avoid energy loss, it actually pulls supplementary energy from its surroundings resulting in an incredible 100% efficiency for the solar input and an additional draw of up to another 170% energy from the water source and surroundings.#

The design displaces excess heat away from the evaporator's top surfaces, dispersing heat to the fin surface for water evaporation, and so cooling the top evaporation surface and achieving zero energy loss during solar evaporation. This heat-sink technology allows for all surfaces of the evaporator to remain cooler in comparison to the encompassing air and water, so additional energy flows from the higher-energy outer perimeter towards the lower-energy evaporator.

XU: "We are the first researchers in the world to extract energy from the bulk water during solar evaporation and use it for evaporation, and this has helped our process become efficient enough to deliver between 10 and 20 liters of fresh water per square meter per day."

Add on to that the fact that the system can be build using only cheaply available common material, and one can't help but feel excited about its potentials. We will continue to follow the developments. The estimated low maintenance costs also mean that a deployed system can remain active for an extended period of time without the need for significant additional funding.

If you are interested in the details of the photothermal evaporator and the underlying research, be sure to check out the paper listed below.

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