Scientists design new polymer paint to keep buildings cool

Researchers from Columbia University say it provides a low-emissions alternative to air conditioners

A new polymer-based paint could help cool down buildings without using any energy.

Researchers from Columbia University have invented a passive daytime radiative cooling (PDRC) polymer that uses tiny air voids to reflect sunlight and radiate heat.

The material can be painted on rooftops, walls, water tanks and even vehicles to dissipate heat to the atmosphere, providing an alternative to energy-intensive cooling methods such as air conditioning.

The polymer has a porous foam-like structure, with a solar reflectance above 96% and a thermal emittance of approximately 97%.

The polymer was recorded as keeping buildings 6°C cooler in the desert of Arizona and 3°C cooler in the tropical climate of Bangladesh.

Yuan Yang, Assistant Professor of Materials Science and Engineering, said: “The fact that cooling is achieved in both desert and tropical climates, without any thermal protection or shielding, demonstrates the utility of our design wherever cooling is required.”

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