KAUST Unveils New Electric-Free Cooling Technology For Efficient Water Harvesting

An international team, led by King Abdullah University of Science and Technology (KAUST) Professor Qiaoqiang Gan, has developed a passive cooling technology. This innovation extracts water from the air using only gravity, without electricity or expensive energy sources. The system uses inexpensive, widely available materials. It can cool electronic devices and repurpose collected water for irrigation, washing, and building cooling.

Scientists highlight that the atmosphere holds six times more water than all river freshwater combined. "This water can be collected by atmospheric water harvesting technologies," says Gan. However, in arid regions like Saudi Arabia, these technologies need electricity to gather significant amounts of water. This requirement could hinder solar cell adoption in rural areas where electricity infrastructure is costly.

KAUST Prof. Dan Daniel and Shakeel Ahmad, a postdoc in Gan's group, discovered that adding a lubricant coating made of a commercial polymer and silicon oil increases water collection efficiency using gravity alone. "A common challenge in atmospheric water harvesting systems is that water droplets tend to remain pinned to the surface of the device, necessitating active condensate collection. Our coating effectively eliminated pinning, enabling true passive water collection driven by water," says Ahmad.

The new system operates entirely on passive radiative cooling without consuming electricity. This solution builds on Gan's previous technology called "vertical double-sided architecture." Initially designed to reflect thermal heat back to the sky for cooling solar cells and electronics outdoors, it did not capture produced water.

The device underwent six tests over a year in Thuwal, about 100 km north of Jeddah. It nearly doubled the rate of water collection compared to other atmospheric harvesting technologies. Daniel is enthusiastic about its economic advantages: "The system does not consume any electricity, leading to energy savings. Moreover, it does not rely on any mechanical parts like compressors or fans, reducing the maintenance over traditional systems, leading to further savings," he said.

This project is part of ongoing research at KAUST's Center of Excellence for Renewable Energy and Sustainable Technologies. Alongside Gan and Daniel, KAUST Associate Professor Gyorgy Szekely contributed to the study published in Advance Materials.

With inputs from SPA