Windows are essential in a building’s design, but they are also the least energy-efficient. According to the US Department of Energy, window-associated energy consumption (heating and cooling) in buildings accounts for approximately 4 per cent of total primary energy consumption in the US each year.
In Singapore, an international research team led by scientists from Nanyang Technological University (NTU) has developed a temperature-adapting glass using a special coating that can adapt to temperatures across different climate conditions globally that could help cut energy costs.
During summer, the glass can suppress the sun’s heat while boosting “radiative cooling” – a natural phenomenon where heat emits through surfaces towards the cold – to make the room cooler. While in winter, it does the opposite to warm up the room.
Dr Long Yi, head researcher of the study, said that most temperature-changing materials could only serve one purpose. For example, energy-saving windows or insulating walls can only reflect short infrared light to make the area cooler, but this becomes undesirable during winter.
The NTU research team believes their innovation offers a convenient way to save energy in structures since it does not rely on any moving components, electrical mechanisms, or blocking views to work.
“This innovation fills the missing gap between traditional smart windows and radiative cooling by paving a new research direction to minimise energy consumption,” added Professor Gang Tan, researcher and scientist, NTU.
As proof of concept, the scientists tested their temperature-adapting glass using simulations of climate data covering seven climate zones worldwide.
The team found that the glass saved energy in warm and cool climates, with a total energy savings of up to 9.5 per cent or 330,000 kWh per year (estimated energy required to power 60 households in Singapore) compared to commercially available low emissivity glass.
The temperature-adapting glass is made using layers of vanadium dioxide nanoparticles composite, Poly(methyl methacrylate) or PMMA, and low-emissivity coating to form a unique structure that could modulate hot and cold simultaneously. In addition, it doesn’t require any electrical components and can work just by adjusting the spectrums of light.
Moreover, the team said that their glass’s heating and cooling performance could be customised to suit the needs of the market and region where it will be installed.
A Singapore patent has been filed for the innovation.