Je-Hyeong Bahk (PI), Vesselin Shanov

University of Cincinnati, Mechanical and Materials Engineering

Purpose:  The purpose of this research is to develop thermoelectric (TE) fabrics that can be embedded in firefighter jackets for both personal cooling and power generation.

Design: We use carbon nanotube (CNT) fibers as the active thermoelectric medium, and they are woven with conventional acrylic or nylon fibers together into fabrics. Sections of CNT fibers are selectively doped into n-type and p-type to make the so-called Π-geometry. The entire fabric is then coated with epoxy resin for electrical insulation to make the final fabric.

Methods: CNT fibers are spun from chemical vapor deposition-grown CNT arrays using the dry spinning method. During the spinning, CNT fibers are twisted to make twisted threads and achieve the desired fiber diameter and mechanical strength. Selected periodic sections of the CNT fiber are dipped into dopant solutions to form doped sections of each p- and n-type. The samples are then tested with varying electric current input to investigate the cooling performance, and with controlled temperature gradients to investigate the power generation performance.

Results: We successfully developed a few fabric samples and tested them for a proof-of-concept study. Our results show that the proposed CNT fabric can be used for effective cooling in firefighter jackets, and for wearable power generation when a large temperature difference is applied between the outside and inside of the jacket.

Conclusion: This work demonstrated the cooling and power generation performance of CNT-based TE fabrics as a proof-of-concept study. Further improvement of material properties and optimization of fabric design will be necessary for future practical application.

Impact Statement: The proposed TE fabric is expected to enhance the thermal comfort of firefighters and thus help significantly reduce the risk of cardiac arrest due to excess heat at a fire scene for them. Even in normal work conditions, the TE cooling fabric will help maintain the temperature inside the suit at the comfort level to reduce mental stresses and physical fatigue. Although it is developed primarily for firefighters, the TE fabric will have broader market opportunities for workers in harsh environment and work conditions including soldiers, construction workers, nurses, and doctors.