Indian Institute of Technology Guwahati have developed energy-efficient bricks designed to keep buildings naturally cool, offering a promising solution for sustainable construction. The findings of this research have been published in the prestigious Journal of Energy Storage in a paper co-authored by Prof. Pankaj Kalita, Associate Professor, along with Dr. Pushpendra Singh, Post Doctoral Fellow, and Mr. Bitupan Das and Ms. Urbashi Bordoloi, recipients of Prime Minister Research Fellowship, School of Energy Science and Engineering, IIT Guwahati.
In modern architecture, most infrastructures rely on air conditioning systems to maintain indoor temperatures, especially during the summer. While these systems are effective, they consume substantial electricity and contribute significantly to carbon emissions and environmental degradation. With a global focus on sustainable living and climate-responsive architecture, researchers worldwide are working towards finding alternative solutions to reduce indoor temperatures without relying on energy-intensive systems.
As a significant amount of heat enters the infrastructure through its roof and walls, researchers at IIT Guwahati focused on addressing this challenge by redesigning conventional bricks to minimise heat gain. For the same, Prof. Pankaj Kalita, along with his research team, applied Phase Change Materials (PCMs), a type of material that can absorb and release heat during phase transitions.
For example, materials such as wax absorb heat as they melt and release it upon solidification. Similarly, when embedded in building components, these PCMs absorb excess heat during the day and release it when the temperature drops. This way, the indoor temperature remains stable throughout the day.
Among the various PCMs tested, the research team found OM35 to be the most suitable for the research. This material melts at around 35 degrees Celsius, making it particularly suitable for hot, humid regions where temperatures range from 28 to 38 degrees Celsius.
Speaking about the use of PCMs in developing climate-responsive infrastructure, Prof. Pankaj Kalita said, “The developed biocomposite-filled Autoclaved Aerated Concrete (AAC) brick is highly stable in shape and offers adequate mechanical strength in hot and humid conditions, making it suitable for infrastructure development.”
While PCMs have proved to be a suitable choice for developing infrastructures for sustainable living, one primary challenge is their leakage during the melting phase. To address this, the research team developed a composite material by integrating the PCM with biochar. Biochar is a carbon-rich material that serves as a supporting matrix, holding the molten PCM in place and preventing leakage while enhancing thermal conductivity.
The bio-composite PCM-filled AAC brick is very convenient to use in construction work. The AAC brick is known for their lightweight and better insulating properties. The integration of biocomposite PCM into AAC bricks further improves the building's thermal performance.