A paint so white that it reflects almost all of the sunlight and, consequently, cools homes, offices, cars or airplanes without using air conditioning. This is the main feature of the paint created by Purdue University, which today presents a second version perfect for use with cars, trains and planes.
Already last year, the engineers of Purdue University had removed the veils on what has been defined, in fact, the whitest white paint in the world. Behind this slogan he hid a white paint with a reflectance – the ability to reflect part of the incident light – of 98.1%. In practice, this particular type of paint reflects almost completely the sunlight, making it perfect in terms of energy efficiency of buildings.
They invented a paint that cools the surfaces. It is ultra-white, and it will be a weapon against global warming
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The use of this paint, in fact, can significantly lower the external temperature of buildings exposed directly to sunlightthus allowing to obtain fresher home and office interiors, without the use of air conditioners or fans.
Under ideal conditions the paint is even capable of guaranteeing an air conditioning effect, lowering the internal temperature compared to the external one.
The paint presented by the American university had only one defect, if we can call it that: “To obtain a level of cooling that brings the temperature below the ambient one, we needed to apply a layer of paint at least 400 microns thick”Said the curator of the project, Xiulin Ruan. “This thickness is fine if you need to paint fixed structures, but it affects too much, in terms of grams, on applications that require strict weight control.“.
In practice, the thickness and weight of the paint layer excluded its use on cars, trains or planes.
To overcome this problem came the second version of the paint: the team abandoned the use of barium sulphate to switch to the use of boron nitride “platelets”. Reflectance dropped slightly – from 98.1% of incident light to 97.9% – but now a layer of 150 microns is enough to obtain the desired results.
Thanks to a much thinner and therefore much lighter layer, Purdue University paint can also be used to paint cars, planes and trains.
“Our paint can cool the exterior of airplanes, cars or trains. Think, for example, of a plane stopped on the tarmac on a summer day, which will no longer have to run the air conditioning at full capacity to cool the interior. This translates into enormous energy savings”Explained Professor Ruan.
The paint, in its second incarnation, could soon make its debut on the market, as soon as the American university has obtained the patents required for commercialization.