Technology, innovation and inspiration are needed so that, in the not too distant future, buildings have better insulation without resorting to large electricity bills and large energy expenditure. Along the way, smart windows emerge, unprecedented ways of taking advantage of human heat, or even new materials to switch from heating to cooling at the flick of a switch.
Now another recent discovery should be cause for celebration for the construction industry: the development of a chameleon-like building material capable of cooling and heating the interior of buildings. It works by changing its infrared color and the amount of heat it absorbs and emits depending on the outside temperature.
The development is carried out by a group of researchers from the Pritzker School of Molecular Engineering (PME) of the University of Chicago: its solution to regulate the temperature of buildings it is “a form of low energy consumption that treats a building like a person”.
“A layer is added when it is cold and another is removed when it is hot,” explains Po-Chun Hsu, director of the research, published in Nature Sustainability.
The intelligent material chameleon has spectacular numbers behind it: it is capable of emitting up to 92% of the infrared heat it contains, thus cooling the interior of a building. And on the coldest days, the material emits only 7% of its infrared, helping to keep the interior warm. In this way, it maintains an ideal temperature without wasting large amounts of energy.
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The material layer can adopt 2 modalities: solid copper that retains most of the infrared heat to keep the building warm; or one infrared emitting aqueous solutionto get a fresh interior.
In a context such as the current climate crisis, it is essential to find solutions that reduce the carbon footprint of buildings. These emit 10% of all global greenhouse gases, of which half correspond to heating and cooling. In addition, they consume 36% of the final energy.
This solution is much more efficient from the energy point of view, and also more flexible and adaptable to climatic variations and extreme weather phenomena, since it is flame retardant and electrochromic -not flammable-
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In addition, the energy expenditure required by this new material is derisory: the device uses a tiny amount of electricity to trigger the chemical change between these states, either by depositing copper in a thin film or by removing that copper.
It also shines with its durability: can alternate “rapidly and reversibly between metallic and liquid states” even after 1,800 cycles.
The calculations carried out by the researchers give a good sample of the energy saving that would imply Creating models applied to 15 different American cities, they concluded that the electricity used would be less than 0.2% of the building’s total electricity consumption, but could save 8.4% of annual heating, ventilation and air conditioning energy consumption.
So far, the material has been used for small parts, about 6 centimeters in diameter. Nevertheless, these patches could also be assembled as shingles, and also modified to custom colors without losing thermal control throughout the seasons.
