High-Performance Transparent Radiative Cooler Designed by Quantum Computing

Abstract

Transparent radiative coolers can be used as window materials to reduce cooling energy needs for buildings and automobiles, which may contribute significantly to addressing climate change challenges. However, it is difficult to achieve high visible transparency and radiative cooling performance simultaneously. Here, we design a visually transparent radiative cooler on the basis of layered photonic structures using a quantum computing-assisted active learning scheme, which combines active data production, machine learning, and quantum annealing in an iterative loop. We experimentally fabricate the designed cooler and demonstrate its cooling effect. This cooler may lead to an annual energy saving of up to 86.3 MJ/m 2 in hot climates compared with normal glass windows. The quantum annealing-assisted active learning scheme may be generalized for the design of other complex materials.

Scalable Colored Subambient Radiative Coolers Based on a Polymer–Tamm Photonic Structure

“…A daytime radiative cooler (DRC), first proposed by Raman, consumes no electricity to reduce the temperature of objects below that of ambient air, the so-called subambient cooling, by strongly reflecting the solar irradiance at λ = 0.3–2.5 μm and simultaneously radiating heat out to the extremely cold universe through an atmospheric transparency window at λ = 8–13 μm . A variety of DRCs have been demonstrated, which are promising for potential applications in energy-efficient buildings, , photovoltaic modules, and personal thermal management . However, the majority of the proposed DRC materials exhibit white or metallic colors to guarantee a strong reflection of the solar irradiance, which is unfavorable in some application scenarios and installation locations such as building envelopes and vehicles for aesthetic purposes and potentially leads to light pollution and eye safety issues.…”

Directional Radiative Cooling via Exceptional Epsilon-Based Microcavities

“…To date, much attention has been paid to accomplishing wavelength-selective thermal emission, which supports the development of thermophotovoltaics, ,,, radiative coolers, ,,− , and infrared camouflaging . In the era of carbon neutrality, radiative coolers are garnering increasing popularity because they do not consume external energy for cooling , and are formed as scalable thin films. ,− In addition, their practical function can be adaptively switched between cooling and heating with the use of temperature-triggered emissivity-changing materials ( e.g.…”

“…To date, much attention has been paid to accomplishing wavelength-selective thermal emission, which supports the development of thermophotovoltaics, ,,, radiative coolers, ,,− , and infrared camouflaging . In the era of carbon neutrality, radiative coolers are garnering increasing popularity because they do not consume external energy for cooling , and are formed as scalable thin films. ,− In addition, their practical function can be adaptively switched between cooling and heating with the use of temperature-triggered emissivity-changing materials ( e.g. , vanadium oxide) to override excessive cooling in cold settings. , In comparison, angle-selective thermal emission is more challenging because of the complexity of design principles. , For example, Greffet et al reported narrow-angle emission at a single thermal wavelength (11.36 μm) in the p polarization by constructing a one-dimensional (1D) wavelength-scale grating (6.25 μm in pitch) on a SiC substrate .…”

“…, 300 K) radiates nearly half of the electromagnetic energy in the atmospheric window (8–14 μm). , Once considered an elusive task, molding the spectrum of thermal emission in the frequency or momentum domain is now conceivable owing to advances in nanophotonics. , For real objects in local thermal equilibrium, Kirchhoff’s law of thermal radiation (i.e., emissivity (ε) equals absorptivity (α)) still holds at every combinatorial specific set of wavelength (λ), angle (θ), and polarization ( p ). Then, nanophotonics is capable of adjusting ε at selected λ, θ, and p using the concepts of photonic crystals, − plasmonic gratings, − hyperbolic metamaterials, , multilayer interference coatings, − Mie scattering, , and Fabry–Perot resonances …”

“…Energy–momentum dispersions were acquired to unravel the underlying physics of the directional emission that peaked at multiple exceptional epsilon wavelengths. In principle, an omnidirectional thermal emitter provides a more efficient way of cooling in an open system, ,− , compared with a directional thermal emitter that restricts its emission in a certain range of angles. However, we note that an omnidirectional thermal emitter can be ineffective in a closed system , because of the greenhouse effect .…”