UNSW researchers develop building materials that adjust to both heat and cold

UNSW researchers are developing new materials that improve on conventional supercooling materials used on buildings to combat the heat.

The work is led by Scientia Professor Mat Santamouris of the university’s School of Built Environment, and the new-generation materials were recently tested in Kolkata, India in a collaboration with two international universities.

According to a statement from UNSW, the solution adds two layers to regular supercooling building materials, which are ineffective in winter and also have issues around creating glare. 

A first layer is of phase change materials made of “transitional metal oxides” and which modulates solar reflectivity and emissivity during the seasons. The second is a fluorescent material which increases how well the solution cools.

The result is a material with a surface temperature above ambient temperature in winter, and below it in summer.

“We have integrated a new layer into the materials which changes the reflectivity and emissivity as a function of the ambient temperature,” said Santamouris. 

“We have also decreased the reflectivity of the materials to decrease glare by integrating [another] new layer that increases heat losses through fluorescence.

“In the recent study, we were not only able to overcome the overcooling issue, but we were able to decrease the peak summer ambient temperature up to five degrees and increase the peak winter temperature by 1.5 degrees.”

He added that it would be adaptable to any climate, could be used at low levels, be any colour, and would also be durable, non-toxic, and affordable when produced at scale.

The team will continue to test their invention around the world and work towards commercialisation. 

Their latest study, titled “Optically Modulated Passive Broadband Daytime Radiative Cooling Materials Can Cool Cities in Summer and Heat Cities in Winter”, can be accessed here.

Picture: www.buildings.com

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