Janus yarn based dual mode fabric for radiative heat management

Personal radiative heat regulation by photonic engineered textiles can help contribute to a more sustainable cooling and heating energy consumption in buildings by expanding the range of comfortable ambient conditions. Here, we propose a Janus yarn structure for a dual mode thermoregulating textile that provides both passive cooling and heating functions by flipping. Using metallic and dielectric fibers within the yarn creates a strong emissivity contrast, benefitting from a plasmonic gap on the one hand, and Fabry-Pérot and multipole localized modes on the other hand. By tailoring the yarn structure, an emissivity contrast Δε=0.72 was achieved resulting in a significant 13°1 C setpoint temperature window, with the wearer staying comfortable between 11.3 and 24.4°C.