Polarization-mediated multi-state infrared system for fine temperature regulation

Passive radiative cooling has been spotlighted as a promising energy-saving cooling technology owing to its energy-free and zero-carbon emission for addressing global energy and climate crises. Although radiative cooling can significantly save cooling energy in hot weather, it inevitably accompanies undesirable cooling in cold weather resulting from a single-state of strong thermal emission. Dual-state emitters have recently been developed for self-adaptive thermoregulation, but they still exhibit energy loss in moderate weather. Herein, we report a continuous temperature-regulation system by introducing an infrared (IR) polarization valve as the energy-balancing channel. The proposed scheme controls the emitter temperature simply by the in-plane rotation of the IR polarizer as if closing and opening the valve, which presents heating/cooling capabilities of -17 to 51 W/m(2) and an energy-saving of > 20 GJ/year compared with the conventional emitters in all climate zones. Outdoor experiments demonstrate the precise temperature regulation with the range of & UDelta;T-cool > 2 & DEG;C. This proof-of-concept demonstration in the outdoors verifies our approach's reliability, suggesting its applicability in residential buildings, farms, and electronic devices.

Automated summary

Passive radiative cooling is a promising energy-saving cooling technology that addresses global energy and climate crises. By introducing an infrared polarization valve as an energy-balancing channel, we propose a continuous temperature-regulation system that provides heating/cooling capabilities in all climate zones and saves energy. Outdoor experiments verify the reliability of our approach and suggest its applicability in residential buildings, farms, and electronic devices.