Composite filament with super high effective thermal conductivity

The low thermal conductivity of the clothing filament constrains the efficiency of the thermal management garments. In this paper, a super thermal conductive composite filament (STCCF) was proposed for body thermal management, which was fabricated by hollow Teflon filaments incorporated with hollow copper filaments in the heating and cooling sections. By introducing R134a into the hollow filament, a thermally driven flow was generated due to the pressure imbalance caused by the evaporation and condensation of R134a, which enhanced the heat transport capability significantly. The apparent thermal conductivity of the STCCF increased with the increasing heat power, being up to 5042 W/(m·K) at the heating temperature of 49 °C. Furthermore, bending only had a small effect on the thermal performance of STCCF due to the flow pattern transition in the curved section. Moreover, the heat transfer capacity could be enhanced by a lower temperature difference between the hot and cool sections under constant heat power. Therefore, the proposed STCCF has great potential for human body thermal management, which could contribute to human health and thermal comfort as well as building energy saving.