A cross-disciplinary team at Rice University has unveiled a groundbreaking electric heating element that could revolutionize the gas heating industry. Unlike traditional metal coils, this innovation resembles a high-performance thread, crafted from carbon nanotube fibers (CNTFs). Published in the journal Small, the study illustrates that CNTF wires and fabrics deliver significantly more heating power per unit mass than conventional metal-alloy heaters when used in flowing gases. This breakthrough points to a promising new pathway for electrifying industrial heating, a crucial yet challenging step towards reducing carbon emissions.
“Electrifying industrial heat is one of the most important, and most difficult, pieces of decarbonization,” stated Monisha Vijay Kumar, a graduate student in applied physics and the study’s first author. “We wanted to understand whether an entirely different class of materials could expand what’s possible in gas heating.”
Revolutionizing Industrial Heating
Industrial facilities frequently heat gases for various processes, including chemical production, drying, thermal treatment, and manufacturing. Traditionally, this heat is generated by burning fuels. While electric heating might seem like a straightforward replacement, the reality is more complex. Heating moving gases imposes severe demands on materials and design, requiring heaters to transfer energy rapidly and evenly into the gas stream while avoiding destructive hot spots, mechanical deformation, and failure under extreme temperatures. Immersion heating, which involves placing heating elements directly in the gas flow, can improve efficiency but also increases material stress.
“When you immerse a heater directly into a gas stream, you gain heat-transfer efficiency, but you also create a much harsher operating environment,” explained Daniel J. Preston, assistant professor of mechanical engineering at Rice University. “Geometry, stability, and performance all become tightly coupled.”
The Advantages of Carbon Nanotube Fibers
One of the most persistent challenges in this field is size. Thinner heating elements exchange heat with gases more effectively, but conventional metal alloys are difficult to fabricate and handle at very small diameters. CNTFs offer a compelling alternative, combining electrical resistivity suitable for Joule heating with exceptional strength-to-weight ratios and unusually high thermal conductivity compared to traditional heater materials.
“Carbon nanotube fibers behave very differently from metal wires,” noted Matteo Pasquali, the A.J. Hartsook Professor of Chemical and Biomolecular Engineering and director of the Carbon Hub. “They are lightweight, flexible, and remarkably strong, which allows us to consider heater geometries and fabrication techniques that would be impractical with conventional materials.”
Innovative Design and Manufacturing
Rather than adapting CNTFs to existing heater designs, the team constructed devices entirely from these fibers, including single filaments, parallel arrays, and textile-like fabrics. Their primary performance metric was specific power loading—the maximum heating power per unit mass a device can sustain before failure. Across various configurations and operating conditions, CNTF heaters consistently achieved higher specific power loadings than comparable metal-alloy elements, particularly in nonoxidizing environments where carbon-based materials can withstand much higher temperatures without degradation.
“Their high thermal conductivity helps distribute heat and suppress localized hot spots, which are a common cause of heater failure,” said Geoff Wehmeyer, assistant professor of mechanical engineering and an expert in nanoscale heat transport. “That heat spreading fundamentally changes how these devices behave under extreme conditions.”
Textile-Inspired Techniques
A distinctive feature of the research is its reliance on textile-inspired manufacturing techniques. CNTF yarns can be woven, knitted, and assembled into lightweight, high-surface area structures—geometries particularly well-suited for immersion heating. Vanessa Sanchez, assistant professor of mechanical engineering, contributed expertise in advanced manufacturing and textile technologies, helping translate nanoscale fibers into device-scale systems.
“Textile techniques give us extraordinary freedom in creating three-dimensional architectures,” Sanchez remarked. “We can design heaters that are lightweight, porous, and mechanically compliant while remaining electrically functional.”
Collaborative Efforts and Future Implications
The project represents a unique convergence of research communities, combining materials synthesis, nanoscale heat-transfer science, device engineering, and manufacturing. It also benefited from collaboration with industrial researchers Robert Headrick and Dhruv Arora at Shell and the research team at DexMat, which has commercialized and scaled up CNTF production.
“This work required multiple layers of expertise,” Wehmeyer emphasized. “Producing high-quality CNTFs is only the starting point. Understanding how they perform thermally and integrating them into functional devices is equally important.”
This research was supported by the National Science Foundation, the Department of Energy, Shell, the Welch Foundation, the Carbon Hub, a NASA Space Technology Graduate Research Opportunity award, and a National GEM Consortium Fellowship. As the world increasingly focuses on reducing carbon emissions, innovations like these could play a crucial role in transforming industrial heating processes, paving the way for a more sustainable future.
