Bioinspired zero-energy thermal-management device based on visible and infrared thermochromism for all-season energy saving.

Radiative thermal management provides a zero-energy strategy to reduce the demands of fossil energy for active thermal management. However, whether solar heating or radiative cooling, one-way temperature control will exacerbate all-season energy consumption during hot summers or cold winters. Inspired by the Himalayan rabbit's hair and Mimosa pudica's leaves, we proposed a dual-mode thermal-management device with two differently selective electromagnetic spectrums. The combination of visible and infrared "thermochromism" enables this device to freely switch between solar heating and radiative cooling modes by spontaneously perceiving the temperature without any external energy consumption. Numerical prediction shows that a dual-mode device exhibits an outstanding potential for all-season energy saving in terms of thermal management beyond most static or single-wavelength, range-regulable, temperature-responsive designs. Such a scalable and cost-efficient device represents a more efficient radiative thermal-management strategy toward applying in a practical scenario with dynamic daily and seasonal variations.