New Delhi, March 27 Researchers at the Indian Institute of Technology (IIT), Guwahati, have developed energy-efficient bricks designed to keep buildings naturally cool, offering a promising solution for sustainable construction, according to officials.
The findings of the research have been published in the prestigious Journal of Energy Storage.
According to Pankaj Kalita, Associate Professor, 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.
"Since a significant amount of heat enters the infrastructure through its roof and walls, we focused on addressing this challenge by redesigning conventional bricks to minimize heat gain. We then applied Phase Change Materials (PCMs), a type of material that can absorb and release heat during phase transitions," Kalita said.
"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," he said.
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.
"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," he said.
To address this, the research team developed a composite material by integrating the PCM with biochar, Kalita said.
"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," he added.
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.
"PCM-embedded bricks are capable of better thermal management in terms of temperature reduction, as they can absorb and store heat during the day and release it gradually when the temperature drops, helping maintain more stable indoor conditions compared to conventional bricks," Kalita said.
To ensure optimal design of the developed bricks, he said, the research team used advanced computer simulations to track heat transfer through AAC bricks with different PCM configurations.
"Based on this, the researchers found that the developed bricks can reduce indoor wall temperatures by approximately 3 degrees Celsius. This reduction in indoor temperature can result in a 10 to 20 per cent decrease in cooling energy demand, depending on building design and usage patterns," Kalita added.
The estimated cost of the developed bricks is in the range of Rs 115 to Rs 130 and is expected to decrease with mass production. As the next step, the research team plans to take this innovation to the commercial stage, likely by setting up a startup.
"The developed innovation has significant implications for energy savings, especially in hot and humid climates, where cooling accounts for a major share of electricity consumption. The new materials can reduce overall energy consumption and peak electricity demand by reducing reliance on air conditioning.
"The new method further improves climate sustainability by reducing greenhouse gas emissions from excessive energy use and by fostering energy-efficient, climate-sensitive buildings. Additionally, it supports the global initiatives of low-carbon construction and the sustainable urbanization of cities," Kalita said.