let’s paint the southwest white!

Es­ti­mated reading time is 2 minutes.

LET’S PAINT THE SOUTH­WEST WHITE! We’ll start with the roofs then move on to dri­ve­ways and parking lots and even­tu­ally the streets, the high­ways, and every­thing else. “Sci­en­tists look for the Holy Grail” ad­dresses the search for cre­ating a sur­face that’s cooler to the touch on a hot summer day than the air around it.

The ar­ticle was written by Emily Pon­tecorvo for Grist and was pub­lished in April 2021. The two years since have en­sured that it will re­main timely for the fore­see­able fu­ture. Here is the gist of the piece (edited for this blog):

White roofs are one of those cli­mate so­lu­tions that sound too good to be true. Com­pared to solar panels and elec­tric cars, painting the roof of a building white is sus­pi­ciously cheap. White roofs re­flect sun­light back into space rather than ab­sorbing it, low­ering building tem­per­a­tures and re­ducing the need for energy-intensive air conditioning. 

Com­pared to solar panels and elec­tric cars, painting the roof of a building white is sus­pi­ciously cheap.

Sci­en­tists are still after the Holy Grail: a paint so white that it per­fectly re­flects the sun’s rays, cre­ating a sur­face that’s cooler to the touch on a hot summer day than the air around it. And now, a team of re­searchers from Purdue Uni­ver­sity in In­diana claim to have come the closest yet.

Xi­ulin Ruan, the pro­fessor of me­chan­ical en­gi­neering who led the re­search, said the av­erage white paint on the market re­flects be­tween 80 and 90 per­cent of the sun­light that hits its sur­face, ab­sorbing the rest. Their new paint re­flects 98.1 percent.

It also pulls off an­other trick. To­tally sep­a­rate from in­ter­ac­tions with sun­light, all sur­faces, in­cluding roofs, ra­diate heat out­ward. With this new paint, the heat lost by ra­di­a­tion is more than the heat gained from the sun. A sur­face coated with the paint main­tained a tem­per­a­ture be­tween 8 and 18 de­grees Fahren­heit lower than the air around it during day­light hours. 

They es­ti­mate that for a 1,600-square-foot building with an av­erage air con­di­tioning system and elec­tricity rate of $0.10 per kilowatt-hour, their paint could re­sult in a sav­ings of $36 per month on cooling.”

To read the ar­ticle in its en­tirety, click here.

 

 Southwest white: photo of a man on a white roof painting it whiter.

FEA­TURED IMAGE: Of course, after we paint the South­west white, we will have to start painting the rest of the South and then, even­tu­ally, every­thing else above the Mason-Dixon Line.


 

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