Personal radiative heat regulation
using photonic textiles can
facilitate decreased energy consumption in buildings by expanding
the range of comfortable ambient conditions. Here, we propose a dual-mode
photonic design that modulates the emissivity using a textured membrane
that changes its surface structure between flat and wrinkled. The
dual nature of the design is achieved through varying high and low
surface emissivity to provide both cooling and heating functions.
Theoretical calculations employing a variety of potential materials
and geometries predict a substantial thermoregulation potential of
the design with a set point window of up to 5.5 °C, which is
achieved using a Lambertian surface texture from zinc oxide at the
frontal surface. Furthermore, we fabricate a proof-of-concept demonstrating
thermal comfort in a set point temperature window of about 3 °C,
with further room for improvement. This design leverages the concept
of diffusing surfaces, well-known in the photovoltaics field, toward
a textile application.