Dual-Mode Fabrics for Radiative Heat Management
M. G. Abebe, A. De Corte, G. Rosolen, and B. Maes
Micro- and Nanophotonic Materials Group, Research Institute for Materials Science and Engineering, University of Mons
Mulunehgeremew.abebe@umons.ac.be
As humanity starts to experience the consequences of climate change, addressing the global energy crisis provides us with an important challenge. Surprisingly, more than half of our energy consumption goes to heating and cooling of large, mostly empty spaces in residential and commercial buildings. Therefore, passive personal thermal management, which creates a localized thermal regulation, can become a critical measure to lower consumption and guarantee a sustainable future.
For personal thermal-management technologies, controlling the radiative heat transfer has gained much attention due to its universality and high tunability, leading to photonic engineered textiles [1]. To a large extent, the human body loses its metabolically generated heat by emitting infrared (IR) radiation centered near 10 μm. Specifically, in an indoor setting such as an office, more than 50% of the heat loss is attributed to IR radiation. Therefore, with proper IR management, one can tailor and design passive temperature regulating textiles [1, 2].
Here we propose two different designs for dual-mode photonic fabrics that provide thermal regulation in both cold and hot environments. The first is a metallic microparticle-based dynamic fabric (MMDF): a dynamic and passive thermal regulating fabric that controls radiative transfer by adapting to the ambient temperature and humidity to modulate the transmittance. We perform a comprehensive numerical study of the design's optical and thermal properties to determine optimized parameters for both heating and cooling functionalities. The dynamic switching is achieved via a shape memory polymer matrix that responds to environmental changes. The design capitalizes on the strong scattering properties of metallic microspheres, leading to a strong modulation of transmittance and reflectance as a function of the volume fraction. The second is a Janus-yarn based double-sided thermoregulating fabric: a passive radiative management textile using asymmetric yarn composition, leading to dual emissivity characteristics. The fabric provides both passive cooling and heating functions by wearing the textile inside-out. The very strong emissivity contrast is achieved by utilizing both metallic and dielectric fibers within the yarn, benefiting from the plasmonic gap on the one hand and Fabry-Pérot and multipole localized modes on the other hand. This tailored combination of reflective and absorptive structures leads to a substantial emissivity asymmetry between the two surfaces of the fabric, and a very large comfortable temperature range [3].
- Abebe M. G., Rosolen G., Khousakoun E., Odent J., Raquez J., Desprez S., and Maes B., Physical Review Applied (2020), 14, 044030.
- Catrysse P.B, Song A.Y., and Fan S., ACS Photonics (2016), 3, 2420.
- Abebe M. G., De Corte A., Rosolen G., and Maes B., Physical Review Applied (2021) accepted.