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Hot Outside? These Walls Sweat to Keep Things Cool


The world will be using a lot more air conditioning, 30 times more in fact no thanks to climate change, according to the Intergovernmental Panel on Climate Change (IPCC).

What’s worse is that all that A/C is generating even more heat.  Already 200 billion kilowatt hours of power is used for cooling in the US and the hot economies of China and India are fast catching up.  So if there was a way to keep ones cool without using electricity, it would make so much sense – not only for our wallet’s health, but that of Mother Earth’s as well.

A team from the Institute for Advanced Architecture of Catalonia in Barcelona is trying to do just that that.  They are developing walls that cool themselves without electricity when the ambient temperature rises.

The system relies on a principle called evaporative cooling.  Water is stored in a material called hydrogel, that absorbs a lot of water and can swell up to 400 times its original size.  When it’s hot, the water in the hydrogel evaporates, hence cooling the air indoors by around 5 degrees centigrade (9 to 10 degrees Fahrenheit). In other words, they’re trying to make the buildings sweat.

When it’s cold, the water is retained.  Water is recharged from rainwater or the building’s grey water.  Also, unlike conventional evaporative coolers, a continuous supply of water is not necessary.  The hydrogel retains the water for days, even months on end.  Though it could be used on its own, when a conventional air conditioning system is used, the hydrogel-infused walls can reduce the energy bill by 28%.

“We believe that the project is a low-cost alternative to meet energy needs and as a system relies on a simple natural process. In this way it is moving design and technology to a more sustainable future that is respectful of its environment,” says the design team.

The team is composed of masters students Akanksha Rathee, Pong Santayanon, and Elena Mitrofanova, professor Areti Markopoulou and assistants Alexandre Dubor and Moritz Begle. I say that they’re a cool bunch!

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