Janus Multilayer for Radiative Cooling and Heating in Double-Side Photonic Thermal System

Abstract

The temperature of outdoor structures, such as automobiles, buildings, and clothing, can be tuned by designing photonic properties. However, particular challenges arise when considering the temperature of an object itself rather than the enclosure in these outdoor structures. We present a double-side photonic thermal (DSPT) system. In the DSPT system, the tunable range of photonic thermal load for heating and cooling functions is calculated by designing the absorption spectra of both sides to adapt to different temperature conditions. These include the proper photonic design of not only the side facing outward but also the inner side and more complex temperature conditions of the object, enclosures, and atmosphere. According to the DSPT mechanisms, we developed a Janus material that can achieve the opposite functions (cooling and heating) with one film by simply flipping the sides of the Janus material, which does not require any additional energy input. The Janus material is designed and fabricated by common materials and a simple multilayer structure, which is attractive for large-scale fabrication. The thermal experiment proved the Janus multilayer could achieve a high temperature in the heating mode and a low temperature in the cooling mode, and the range of the tunable temperature would be wider with stronger sun radiation. The Janus material can passively achieve more efficient temperature control in enclosures while offering both side photonic design comparable to conventional radiative coolers and heaters.

Solar and Thermal Radiation‐Modulation Materials for Building Applications

“…Opaque Components: The mechanical-driven material with tunable solar and thermal radiation modulation is achieved by simply flipping over a Janus membrane, which shows opposite optical properties on different sides. [168,169] Song et al [168] fabricated a multi-layer structure consisting of polyvinylidene fluoride (PVDF)/ZnO nanosheet/carbon nanotube (CNT)/Ag nanowire (AGNW)/PDMS (Figure 15c). When PVDF faced toward the outdoor ambient, the membrane achieved solar reflectance of 90.6% and mid-infrared emis-sivity of 89.2% mainly due to the radiative cooling properties of the nanostructures of the PVDF fibers (Figure 15d).…”

“…Experimental results indicated that the indoor temperature can be decreased by 14 °C in cooling mode but increased by 4.8 °C in heating mode using the membrane. Similarly, Wang et al [169] developed a Janus membrane that can achieve both heating and cooling by simply flipping. The membrane is fabricated into multi-layer structure made of commonly used materials (e.g., PDMS, silicon dioxide), which is attractive for large-scale fabrication.…”

“…The mechanical‐driven material with tunable solar and thermal radiation modulation is achieved by simply flipping over a Janus membrane, which shows opposite optical properties on different sides. [ 168,169 ] Song et al. [ 168 ] fabricated a multi‐layer structure consisting of polyvinylidene fluoride (PVDF)/ZnO nanosheet/carbon nanotube (CNT)/Ag nanowire (AGNW)/PDMS (Figure 15c).…”

“…Similarly, Wang et al. [ 169 ] developed a Janus membrane that can achieve both heating and cooling by simply flipping. The membrane is fabricated into multi‐layer structure made of commonly used materials (e.g., PDMS, silicon dioxide), which is attractive for large‐scale fabrication.…”

Temperature-dependent dual-mode thermal management device with net zero energy for year-round energy saving

“…Up to now, several approaches have been designed to dynamically regulate the spectral characteristics of dual-mode thermal management in the literature (Supplementary Table 1) [21][22][23][24][25][26][27][28][29][30][31] . However, there is more or less external energy cost for switching between heating and cooling modes, such as using mechanical energy or electrical energy.…”