Speaker 1: Welcome to brain Stuff, a production of iHeart Radio, Hey
Speaker 1: brain Stuff Lauren Vogel bomb Here at noon on a
Speaker 1: sunny summer day, the temperature of a conventional dark colored
Speaker 1: flat roof can reach a hundred and fifty degrees fahrenheit
Speaker 1: that's sixty five degrees celsius, according to the U. S
Speaker 1: Department of Energy, and that heat will warm the inside
Speaker 1: of the building or home as well, making it more
Speaker 1: likely that the occupants will turn to air conditioning, an
Speaker 1: energy expenditure that often requires burning fossil fuels at electrical
Speaker 1: power plants, whose emissions contribute to the progression of climate change.
Speaker 1: It's a bedeviling problem that might easily be solved if
Speaker 1: we only had roofs that reflected solar energy back into
Speaker 1: the sky instead of absorbing it. It's a deviling problem
Speaker 1: that might be easily solved if we could only have
Speaker 1: roofs that reflected solar energy back into the sky instead
Speaker 1: of absorbing it. That's why researchers development of the whitest
Speaker 1: paint ever created an ultra white formulation that reflects up
Speaker 1: to nine point one percent of sunlight could turn out
Speaker 1: to be a really big deal in the effort to
Speaker 1: reduce energy consumption and combat the warming of our planet.
Speaker 1: The breakthrough is detailed in April issue of Applied Materials
Speaker 1: and Interfaces, an American Chemical Society journal, and not only
Speaker 1: does the paint absorb very little energy from sunlight, but
Speaker 1: it also emits thermal energy in the infrared range back
Speaker 1: into the atmosphere so that it travels out and away
Speaker 1: from Earth before the article. This episode is based on
Speaker 1: how Stuff Works. Spoke by email with Zen You Lee,
Speaker 1: the paper's first author. He's a postdoctoral researcher at the
Speaker 1: Massachusetts Institute of Technology who worked on the project while
Speaker 1: in graduate school at Purdue. He said this paint not
Speaker 1: only reflects the majority of the sunlight to avoid overheating,
Speaker 1: but also cools itself down colder than the air surrounding
Speaker 1: it even under direct sunlight. In some way, it's effectively
Speaker 1: an air conditioner without consuming any electricity. Researchers have been
Speaker 1: trying to make paints that could be used in passive
Speaker 1: cooling since the nineteen seventies, but most of them have
Speaker 1: absorbed too much sunlight, so they don't provide any cooling
Speaker 1: effect in the daytime. Lee explained, in recent years, scientists
Speaker 1: have also been exploring exotic technologies for creating light reflecting surfaces,
Speaker 1: such as multi layered nanostructured films, but those solutions tend
Speaker 1: to be expensive and not easily scalable to buildings. That
Speaker 1: brought this team of researchers back to thinking that the
Speaker 1: best approach might be a particle polymer composite similar to
Speaker 1: commercial paint. Ordinary white paint isn't quite white enough to
Speaker 1: help much with passive cooling. It only reflects eight of
Speaker 1: sunlight and actually gets warmer from absorbing ultraviolet light, and
Speaker 1: so the task became finding a way to make white
Speaker 1: paint even whiter, and that turned out to be a challenge.
Speaker 1: Alice said. We first tried multiple materials with high electron
Speaker 1: band gap to avoid solar absorption. However, the paints often
Speaker 1: appeared semi transparent at low thickness due to the lack
Speaker 1: of ability to reflect sunlight. During our previous studies on
Speaker 1: commercial paints and theoretical modeling, we identified that both high
Speaker 1: concentration and broad particle size distribution were beneficial. As we
Speaker 1: implemented these two approaches, we saw the paint solution appere
Speaker 1: wider compared to previous attempts, they landed on burying sulfate
Speaker 1: as a way to make the paint very reflective and
Speaker 1: thus very white. You may have heard of burying sulfate before.
Speaker 1: It's the stuff that medical patients take in drink or
Speaker 1: tablet form to code the esophagus, stomach, and intestines when
Speaker 1: they're getting an X ray exam or CT scan, so
Speaker 1: the doctors can see diseased or damaged areas more clearly.
Speaker 1: As a paint ingrediently notes it's already widely available safe
Speaker 1: for humans and the environment. The researchers used a variety
Speaker 1: of sizes of barry and sulfate particles in the paint,
Speaker 1: which enabled the paint to scatter more of the spectrum.
Speaker 1: They also had to make sure that the paint would
Speaker 1: last long enough outside to be suitable for painting rooftops.
Speaker 1: Lee explained, we tested the abrasion resistance, three week outdoor weathering,
Speaker 1: and a water rinse test. All three showed promising results
Speaker 1: as initial durability tests. We also tested the viscosity and
Speaker 1: the paints can be brushed and dried very similar to
Speaker 1: commercial paint. It can also be fabricated in a similar way.
Speaker 1: In this work, we not only achieved a paint that's
Speaker 1: superior to the commercial paint, but also do not need
Speaker 1: specialized equipment or materials to fabricate, transport, or apply the paint.
Speaker 1: The ultra white paint looks pretty similar to regular white
Speaker 1: paint because the difference in reflectivity, while significant in terms
Speaker 1: of cooling, is imperceptible to humanize. The next step in
Speaker 1: the research is to optimize the paint for long term
Speaker 1: durability under different sorts of weather conditions, but there isn't
Speaker 1: yet a target date for it to be market ready,
Speaker 1: so don't search for it at your local hardware store
Speaker 1: just yet. Today's episode is based on the article the
Speaker 1: whitest paint Ever produced could save energy climate change on
Speaker 1: how stuff works dot com, written by Patrick J. Keiger.
Speaker 1: Brain Stuff is production of I Heart Radio in partnership
Speaker 1: with how stuff works dot com, and it is produced
Speaker 1: by Tyler clang. Or more podcasts my heart Radio, visit
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Speaker 1: to your favorite shows.