Utilising plastic waste, the team engineered thin-film aerogels that function as thermal insulators and radiative coolers. According to NUS, these aerogels can be applied to any surface, such as roofs, to reduce internal temperatures, offering a scalable and sustainable solution for energy-free thermal management. The team’s findings are published in Solar Energy.
In another study, published in Carbon, the NUS researchers devised a simple, scalable method to produce aerogels that absorb EMWs in the X-band, which is characteristic of those used in weather monitoring and air traffic control.
Traditional cooling systems, such as air conditioners, account for approximately 20 per cent of electricity used in buildings worldwide. The new aerogels developed by the NUS team are claimed to present a passive cooling alternative, using the natural process of radiative cooling to dissipate heat into space without consuming energy.
“This process involves using specially engineered aerogels to emit infrared radiation through the atmospheric ‘sky window’, effectively cooling surface temperatures below ambient levels,” research lead Associate Professor Duong Hai-Minh said in a statement. “We are excited to be able to upcycle fibres from disposable polyethylene terephthalate [PET] bottles for the new aerogels designed for this purpose, to help address the global plastic waste crisis.”
Related content
Previously the team had worked with PET fibres to produce aerogels, but this latest method is more energy-efficient, consuming about 97 per cent less energy and reducing production time by 96 per cent. When tested in Singapore’s warm climate, conducted in collaboration with Dr Jaesuk Hwang from the Centre for Quantum Technologies at NUS, 0.5cm of the material produced a cooling effect of 2°C, achieved by emitting infrared heat into the surroundings while exhibiting good heat insulation, preventing heat absorption from the surrounding environment.
“These aerogels could reduce energy consumption in both residential and commercial buildings, especially in tropical climates where cooling is now a necessity,” said Assoc Prof Duong, from the NUS Department of Mechanical Engineering.
Future research will focus on adapting these aerogels for diverse climatic conditions and expanding their applications beyond building insulation.
EMWs
Modern electronic devices emit EMWs that can disrupt nearby equipment and pose health risks, including DNA damage and cancer.
To address this, Assoc Prof Duong’s team has developed a scalable and eco-friendly procedure to produce novel aerogels that are effective at EMW absorption. The process involves blending three main components - carbon nanotubes, polyvinyl alcohol and carboxymethyl cellulose - followed by freeze-drying.
The aerogel, with a thickness of about 3mm absorbed 99.99 per cent of EMW energy. Across the entire X-band (8.2–12.4GHz) of the electromagnetic spectrum, used primarily for radar systems, weather monitoring and air traffic control, the aerogel showed its ability to absorb 90 per cent of EMW energy.
“In addition to offering a wide absorption bandwidth of 1.2–2.2GHz in the X-band, our aerogel is also about 10 times lighter than existing composites used for EMW absorption,” said Assoc Prof Duong. “Unlike other composites, our aerogel requires no mixing with heavy polymer fillers before use.”
The team plans to refine the aerogel’s mechanical properties to broaden their applicability across various building and infrastructure projects. The researchers also aim to conduct real-world tests to fully assess the EMW absorption capabilities of the aerogels.
Visit our jobs site https://jobs.theengineer.co.uk/ to find out about some of the latest career opportunities at industry's biggest employers
Hard hat mounted air curtain adds layer of protection
Something similar was used by miners decades ago!