IIT Researchers develop smart windows that regulate light, heat, conserve power in buildings

Temperature control(heating/cooling) and lighting are regarded as the predominant energy-consuming resources in large buildings and office complexes that use conventional glass windows. Researchers from IIT Guwahati claim to have developed smart window materials that can control the amount of light and heat permeating through when a voltage is passed through it. They say this can help develop efficient automatic climate control systems in buildings. 

Smart window materials developed by the researchers make use of noble metals and their comparatively inexpensive alternatives. According to Ashish Kumar Chowdhary, a Research Scholar IIT Guwahati, their design involved having electro-optical polymer that was sandwiched between ultra-thin metal layers. The filtering of light would thus be enabled by applying a voltage and changing the refractive index (how light moves through a material) of the electro-optical polymer. 

While performing simulations, researchers considered using gold and silver as the outer metal layers but conducted the tests with copper and indium tin oxide. Researchers claim that under certain conditions the smart glass was able to selectively filter solar radiation that spans the visible, infrared and shortwave infrared wavelengths, including heat and light reflected from neighbouring buildings and structures. The results of this study have recently been published in the journal, Solar Energy Materials and Solar Cells.

The team believes that such smart materials can be applied to obtain efficient automatic climate control in vehicles, locomotives, airplanes and greenhouses of the future. They claim that the material proposed by their team can easily be fabricated using existing state-of-the-art nanoscale fabrication methods such as e-beam evaporation and graphoepitaxy techniques. According to the researchers, the working of these materials is dependent on the surface smoothness and other physical properties of the layers. The team plans to conduct further studies on the same.

“We believe that our smart windows can provide an alternative solution for maintaining ambient indoor temperature and lighting inside a building or a vehicle by integrating those with usual glass windows or walls, thereby reducing the need of air-conditioning systems " said Dr. Debabrata Sikdar, Assistant Professor, Department of Electronics and Electrical Engineering.