Cooling system uses salt and water instead of electricity (2024)

Spotted:One key challengefor global sustainable developmentisthe need to reduce energy usage,especially in regions which are becoming hotter.As the planet continues to heat up, it is going to become increasinglynecessary to developan inexpensive cooling technology thatdoes not needelectricity. A research teamat Saudi Arabia’s King Abdullah University of Science and Technology (KAUST) hascome with a way to accomplish this, by using sunlight and saltwater – but no electricity – to cool buildings.

The experimental setup was led by Professor Peng Wang, whose work focuses onphotoelectrocatalysis, a process whereby chemical solar cells harvest sunlight and use the energy to upgrade chemicals rather than deliver electricity. The proposed solutiontakes advantage ofthe phase change in salt crystals. The crystals absorb energy when they dissolve in water. So, if salt is added to warm water, the water then cools as the salt dissolves.

Wang’s team experimented with differentsalts, andfound that ammonium nitrate provided the greatest cooling power.In the lab,theammonium nitrate was added to water and placed inside a sealed, insulated box. As the salt dissolved, the temperature of the water dropped by around 21ºC overa period of20minutesandremained cool for more than 15 hours.Solar heat was then used to evaporate the water and recover theammonium nitratecrystals, which could then be reused.

In apaperpublished in the journal  Energy and Environmental Science,professorWang and the other authorshighlight the need for passive cooling systems, especially in lesser-developed regions. They point outthat, “globally, there are over 700 million people living in impoverished regions who still do not have access to electricity and thus are unable to enjoy the modern era cooling technologies. In this case, developing an inexpensive cooling technology that operates in the absence of electricity is highly desired and can significantly improve the living standards of those who are left behind by modern human development.”

As the Earth warms, energy shortages are becoming increasingly common, and the KAUST researchers are not the only ones searching for a solution to these issues. Springwise has recently coveredinnovations in this space, including adecentralized coolingsystem andthe growing use ofpassive designin heating and cooling.

Written By: Lisa Magloff

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