GUWAHATI, May 25: A two-member research team from Indian Institute of Technology (IIT), Guwahati has developed smart window materials for automatic climate control of buildings, which will save energy and reduce carbon emissions.
The team, comprising Debabrata Sikdar, assistant professor, department of electronics and electrical engineering and research scholar Ashish Kumar Chowdhary, has designed smart window materials that can effectively control the amount of heat and light passing through it in response to an applied voltage.
“Such smart window materials will help develop efficient automatic climate control systems in buildings. The results of their study have recently been published in the journal, Solar Energy Materials and Solar Cells,” a statement issued here on Tuesday said.
According to the United Nations Environment Programme, buildings around the globe account for 36 percent of energy use and 39 percent of energy-related carbon dioxide emissions annually.
The primary consumption of energy in buildings is by the climate control system, in which energy-consuming devices are used to maintain comfortable indoor temperature and brightness. Hence, heating, cooling and lighting loads are major energy-consumption segments in any building.
“There has been increased attention to sustainable architectural designs for better light and heat management in buildings in recent years, and deploying smart windows is the first step for such structures,” Sikdar said.
Conventionally, window designs are static. In other words, they are predesigned for specific climatic conditions.
The emergent smart windows, on the other hand, can dynamically adjust the amount of light and heat radiation entering a building in response to external stimuli, thus conserving the building’s energy.
The researchers designed smart window ‘glasses’ using noble metals as well as their relatively inexpensive alternatives that can dynamically control the intensity of transmitted solar radiation, depending upon the climatic condition.
“We have proposed an electro-tuneable glass made of two ultra-thin metal layers, sandwiching an electro-optic polymer whose refractive index can be changed by applying a small voltage which allows filtering of visible and infrared radiation,” Chowdhary said.
The team used this design to perform simulation studies to understand the light and heat transmission properties in response to the applied voltage.
When the researchers simulated the application of a bias voltage ranging from −15 V to +15 V across this sandwich structure using Finite Element Methods, the smart glass could selectively filter solar radiation, spanning the visible, infrared and shortwave infrared wavelengths.
“The COVID-19 pandemic has imposed an unprecedented risk of cross-infections through aerosol transmission in public buildings where central air-conditioning systems are used. But our smart windows can provide an alternative solution for maintaining ambient indoor temperature and lighting inside a building or vehicle by integrating those with usual glass windows or walls, thereby reducing the need of air-conditioning systems,” Sikdar said.