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Polymer paint passively cools down any surface

整理: 918时间: 2018-10-08

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The porous polymer coating reflects sunlight and emits heat to passively cool off buildings. Credit: Jyotirmoy Mandal/Columbia Engineering.

Heat-waves are on the rise all over the world, becoming more frequent AAA more intense. Developing countries are the hardest hit: not only are heat waves more extreme than in other parts of the world but cooling methods are also more difficult to implement due to cost. In such situations, passive cooling — which doesn’t require electricity or any kind of energy input — is the way to go.

Plastics and other cheap polymers are actually excellent heat radiators, which would make them ideal for passive daytime radiative cooling (PDRC) if scientists could figure out how to get these normally transparent surfaces to reflect sunlight without using silver mirrors.

Researchers at Columbia University have finally been able to accomplish this. Reporting in the journal Science, the authors described a PDRC polymer coating with nano- and micro-scale voids that act as passive air coolers. The amazing part is that the coating can be applied like paint on rooftops, buildings, vehicles — basically anything.

Apply and cool

A passive cooling surface is effective when it has a high solar reflectance and emittance. In other words, if these two variables are high enough, there’s a net heat loss effect ever under intense sunlight.

The cheapest and, often times, most practical PDRC is white paint. If you’ve ever switched a black shirt for a white shirt on a hot summer day, you must know how much of a difference this can make.

本文源自: 揭秘环亚娱乐骗局

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