This remarkable cooling system runs on sunlight and saltwater—no elect

It’s straightforward to neglect as you learn this out of your cellphone or your laptop computer, however 940 million people —or 13% of the world — don’t have entry to electrical energy. Lots of them stay in searing scorching, arid international locations like Niger or Mali, the place air-con is a luxurious and the infrastructure for photo voltaic power is greater than missing. A brand new know-how may assist them settle down with out electrical energy — all because of a primary chemical response.

In response to a 2018 report from the Worldwide Vitality Company, air conditioners and electrical followers account for 10% of the world’s electrical energy consumption, a quantity that’s anticipated to develop as common international temperatures rise. This is especially problematic in arid areas that don’t have the infrastructure to maintain individuals cool within the first place.

[Image: courtesy King Abdullah University of Science and Technology]

This new technology, being developed at Saudi Arabia’s King Abdullah College of Science and Expertise, is in its early levels, but when profitable, may provide a promising resolution. When sure salts are dissolved in water, they soak up warmth, which cools down the water. When constructed right into a large-scale system, the know-how may present a cooling impact with out the necessity for electrical energy. “In underdeveloped areas, this will help them retailer meals for a pair extra days,” says Dr. Peng Wang, an environmental science and engineering professor at King Abdullah College of Science and Expertise who’s main the analysis. When his crew examined the system in a lab, the temperature remained under 50°F for eight hours and beneath 59°F for over 15 hours, which might be sufficient to retailer meals for at some point.

The know-how is available in two components. First, the salt must be dissolved in water, then it needs to be regenerated so it may be reused over and over once more. To do this, Dr. Wang’s crew used sunlight, which causes water to evaporate and leaves the salt solids behind. For now, this course of happens in a black, cup-shaped construction that may soak up photo voltaic power and convert it to warmth, which then helps with the water evaporation.


To date, the researchers have constructed a proof-of-concept at a laboratory scale. Subsequent, they wish to construct an illustration unit. “It may be as huge as a daily fridge or as small as your lunchbox dimension,” explains Wang. It may additionally come as a waterbed. “For those who change the water inside your mattress, you could have your self a cooling mattress,” he says. As for the regenerating system itself, that may be stored on the roof or within the yard. Wang concedes the method just isn’t quick, as it might take one hour to revive the salt in two liters of water.

Dr. Wang explains that photo voltaic power might be saved for later use, which means cooling can be accessible be on-demand, not simply when the salts are regenerated. “You need to use immediately’s photo voltaic power to supply cooling energy in every week,” he says.

After experimenting with varied salts, the researchers landed on ammonium nitrate. It’s straightforward to dissolve, and it’s a typical fertilizer, so sourcing received’t be a difficulty, even for particular person households. And whereas it’s too early to speak about value, he says the most costly half could be sourcing the water, particularly in arid areas. In distant areas the place water isn’t simply accessible, this looks as if a significant impediment, and Wang admits it’s his greatest concern, so his crew is now working on methods to get better the water in sustainable methods.

For Dr. Albert Vega, who runs an organization that helps these impacted by pure disasters discover renewable power options, the chemical response on the coronary heart of this know-how is a recognized course of. “An important instance of this can be a chilly compress [which comes with salt] that healthcare staff use for accidents,” he explains. The place the idea stands out, nonetheless, is in its skill to supply on-demand cooling. He notes, nonetheless, that ammonium nitrate may pose some questions of safety. Because the 2020 Beirut explosion proved, this can be a extremely reactive substance that must be dealt with and saved correctly. “Nothing is a silver bullet,” says Vega. “Nothing is the entire resolution, however the place this know-how will help, the higher objective is each encouraging and thrilling.”

Finally, this wouldn’t be sufficient to energy a whole house, however it may make meals storage simpler, or assist preserve medication cool. In much less distant areas, the know-how might be additionally used together with standard electrical energy. Wang says centralized methods are finest for extremely urbanized cities, however the know-how may bear fruit deep within the countryside, the place it is probably not cost-effective for houses to connect with the grid. “Our system is used at a small scale and your expectation shouldn’t be excessive,” he says, “however it’s passive, pushed by renewable power, it has a really small carbon footprint, and it offers you flexibility.”