High Specific Power Loading of Carbon Nanotube Fiber Devices for Gas Heating.

Electrifying industrial heating to reduce Scope 1 emissions will require advanced Joule heating materials and high-power loading devices that enable effective immersion heating of flowing gases. This work shows that solution-spun carbon nanotube fibers (CNTFs) represent promising alternatives to legacy heating materials such as metal alloys for these electrification applications. Annealed CNTFs have similar electrical resistivity to commonly used nichrome alloys while also offering higher specific strength, higher thermal conductivity, higher operating temperatures in non-oxidizing gases, and the ability to be processed with established textile manufacturing techniques. Joule heating experiments are supported by thermal modeling to quantify the power loading of substrate-free devices made entirely of CNTF monofilaments or CNTF fabrics. Single-filament heating experiments in quiescent fluids show that CNTF wires can achieve specific power loadings that are 32x (inert gas) or 3.5x (air) larger than those of nichrome wires with similar diameters, and experiments on self-heated CNTF textiles show 2.4x specific power enhancement in flowing air as compared to nichrome meshes. Thus, this work shows that annealed CNTF wires, arrays, and textiles are a promising material platform to assist in the electrification of industrial gas heating applications.