A Dual‐Mode Infrared Asymmetric Photonic Structure for All‐Season Passive Radiative Cooling and Heating

Abstract

Radiative cooling is a revolutionary sustainable thermoregulating technology in favor to fight against global warming and urban heat island effects. However, the conventional designed high infrared emissive coolers do not function satisfactorily under atmospheric counter radiation (cloudy, humid, reduced sky access conditions) nor for all‐season thermal requirement (cooling and/or heating). Dual‐mode asymmetric photonic mirror (APM) consisted of silicon‐based diffractive gratings is presented, approaching an all‐season and all‐terrain optimized radiative thermal regulation. Based on the mechanism of asymmetric diffraction through high refractive index contrast mediums, the designed APM establishes an asymmetric radiative heat transfer channel for cooling and heating. An average infrared asymmetry of 20% for outgoing and incoming radiation is achieved by the fabricated APM. The remarkable cooling power of APM surpasses 80% over the standalone radiative cooler (RC) for counter radiation conditions. Under cloudy sky, the cooling‐APM achieves 8 °C lower than RC standalone, while the heating‐APM 5.7 °C higher, which presents prominent advantages over conventional coolers for different thermal management needs. The proposed dual‐mode infrared asymmetric photonic structure is promising to overcome shortcomings of conventional radiative cooling and offers breakthrough developments in future energy‐saving thermal management system.

Recent Advances in Material Engineering and Applications for Passive Daytime Radiative Cooling

“…Optical dynamic switching by external activation has also been reported in recent years. The choices of external activation include stretching/compression, [ 154 ] wetting, [ 155,156 ] mechanical moving parts, [ 157–159 ] physical flipping [ 160–164 ] and applied voltage. [ 165 ] Zhao et al.…”

Dual-Mode Porous Polymeric Films with Coral-like Hierarchical Structure for All-Day Radiative Cooling and Heating

“…Radiative thermal management, particularly for passive radiative cooling (PRC) and passive radiative heating (PRH) without additional energy input, has drawn increasing attention in academia and industries as an alternative for traditional energy-intensive cooling/heating approaches. − PRC uses cold outer space (∼3 K) as the ultimate heat sink for the earth through the transparent atmospheric window (i.e., 8–13 μm). , For all-day PRC, particularly in the daytime, high emissivity within the atmospheric window and high solar reflection within the solar spectrum (i.e., 0.3–2.5 μm) of materials are synchronously anticipated to realize net cooling power under direct solar irradiation . Various material morphologies (e.g., film, − coating, , textile, and aerogel) and material structures (e.g., multilayer structure, , metamaterial structure, , randomly distributed particle, , and porous structure , ) have been developed to realize efficient all-day PRC.…”

Hierarchically Porous Cellulose-Based Radiative Cooler for Zero-Energy Food Preservation

“…In recent years, about 13% of global energy consumption and a large amount of CO 2 emissions are caused by cooling technology, which brings serious consequences such as ozone depletion, air pollution and global warming. , With the increasing demand for fresh food quality, the energy consumed by the food cold chain places a huge burden on the environment and nonrenewable oil resources. It is estimated that the cold chain required to preserve 40% of global food (∼400 million tons) consumes 11% of global electricity, resulting in approximately 2.5% of the world’s greenhouse gas emissions. , On the other hand, inadequate refrigeration facilities and electricity supply also lead to significant food loss and waste in transportation, retail sales, and storage, especially in some less developed countries and regions. , When exposed to strong sunlight and hot temperatures, food will suffer from adverse quality changes like sunburn, dehydration, and deterioration .…”