We have always been warned not to eat the small silica gel packets that come in new shoeboxes, but it is silica that could be the answer to ending the world’s water shortage.
The substance is part of a new technology created by a group of Australian researchers that converts the air’s humidity into drinkable water.
Led by expert in chemical engineering, Behdad Moghtaderi, the Hydro Harvest Operation research team created the technology for the worldwide XPRIZE competition, which aims to solve the global water shortage crisis.
Competition organisers said there is more than three quadrillion gallons of untapped water in the atmosphere, which is enough to meet the needs of every person in the world for one year.
The University of Newcastle team said they wanted to keep the technology simple to ensure it would have worldwide applications, especially for developing countries.
They used desiccant, like that found in silica gel packets, because of it’s ability to absorb moisture.
Using solar energy to make condensation
The environmentally friendly system can work anywhere, without being bound to climate, Professor Moghtaderi explained.
“Atmospheric water generators are usually based on refrigeration cycles that cool the air to below the dew point, the point at which condensation will form, but we’re turning that idea on its head,” Professor Moghtaderi said.
“Our process is based on heating the air, not cooling.”
Professor Moghtaderi said the process uses solar energy to create condensation.
“The first step is to absorb water at night using the desiccant [silica], then we use solar energy during the day to produce hot, humid air that can then be cooled,” Professor Moghtaderi explained.
“The hotter the air, the more water it’s going to hold and then by cooling that hot air, we get water.”
“There are no fancy materials — it’s purely looking at how air holds water and how that changes with temperature, and then how we can engineer a solution based on those known properties,” research team member, Elham Doroodchi said.
Though the team would like to see the technology utilised in developing countries with limited access to clean drinking water, they believe it has a use closer to home too.
“Systems like this can be used anywhere in the world,” Professor Moghtaderi said.
“In fact, you could apply them back in Australia where it’s difficult to get drinkable water where the weather’s so dry.”
Cheap, efficient and green
Professor Moghtaderi and his Hydro Harvest Operation team are the only Australian researchers to reach the finals of the XPRIZE competition.
The brief for the challenge was anything but simple.
Teams were required to create a device that extracts a minimum of 2,000 litres of water per day from the atmosphere, using 100 per cent renewable energy, at a cost of no more than two cents per litre.
The Newcastle team will join four teams from India, USA and the UK in the competitions finale in August, 2018.
The team said, even if they do not win, they will continue to pursue the idea, to ensure clean drinking water for all.