Window film molecule captures the sun

A window film could be capable of offsetting the worst midday heat and distributing that heat evenly from morning to evening, thanks to a specially designed molecule. The molecule is part of a concept that researchers at Chalmers University of Technology call molecular solar thermal storage, or MOST.

Lead researcher, chemist Kasper Moth-Poulsen, envisions office complexes and airports using the film to reduce energy consumption while responding better to rapid temperature fluctuations within the buildings. When the sun’s rays land on the molecule, it is designed to be isomerised, capturing photons and simultaneously changing form. When the sun stops shining on the window film, the molecules are said to release heat for up to eight hours.

“The aim is to create a pleasant indoor environment even when the sun is at its hottest, without consuming any energy or having to shut ourselves behind blinds. Why not make the most of the energy that we get free of charge, instead of trying to fight it?” said Moth-Poulsen. 

The film appears yellow-orange when it has not absorbed solar energy. When the molecule captures solar energy and is isomerised, it loses its color and becomes transparent. The film is capturing energy as long as the sun is shining, which means less heat is transferred into the room. When less sunlight hits the film, heat starts to be released and the film gradually returns to yellow, ready to capture sunlight the next day.

The researchers’ next challenges are to increase the concentration of the molecule in the film while maintaining the desired properties and to bring down the price of the molecule.

The research was funded by the Australian Research Council, the Knut and Alice Wallenberg Foundation and the Swedish Strategic Research Foundation. The team’s research was presented in “Solar Energy Storage by Molecular Norbornadiene–Quadricyclane Photoswitches: Polymer Film Devices.” Findings were published in Advanced Science. 

Information provided by Chalmers University via mynewsdesk.com. Chalmers University of Technology in Gothenburg, Sweden, conducts research and education in technology and natural sciences at an international level.