Self-adaptive integration of photothermal and radiative cooling for continuous energy harvesting from the sun and outer space

Abstract

Significance The sun (∼6,000 K) and outer space (∼3 K) are two natural energy resources for humans. However, most of the approaches of energy harvesting from the sun and rejecting energy to outer space are achieved independently using absorbers and emitters with static spectral properties. Herein, a spectrally self-adaptive structure with strong solar absorption and switchable emissivity within the atmospheric window (i.e., 8 to 13 μm) is experimentally demonstrated to achieve diurnal solar thermal and nocturnal radiative cooling efficiently. The experiment shows that the proposed structure not only can be heated to 185°C in diurnal mode but also be cooled to −12°C in nocturnal mode. This work opens new possibilities for continuously efficient energy harvesting utilizing the sun and the universe.

Supreme-black levels enabled by touchproof microcavity surface texture on anti-backscatter matrix

“…Super-black materials (7)(8)(9)(10)(11)(12)(13), including bioinspired antireflective micro/nanostructures (14)(15)(16)(17), have been attracting a lot of interest. However, most studies have focused on their light energy applications (8,9,(18)(19)(20), which benefit from their thinness (21), thermal efficiency (8,9,20,22), wavelength selectivity (19,(23)(24)(25)(26), and adaptability (27)(28)(29), rather than perfect blackness. Previously developed touchproof super-black materials have exhibited hemispherical reflectance of no less than 0.003 to 0.004 (12,30), which is still too high for use in rigorous light management.…”

Integration of daytime radiative cooling and solar heating

“…Although this field has been widely explored in the past few years, it is still in its early stages. To further promote research in this field and effectively solve its problems, we summarize the previous results from two aspects, switch mode (including electrical, 13 , 14 , 15 thermal-responsive, 16 , 17 , 18 , 19 , 20 and mechanical regulations 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ) and collaborative mode, 29 , 30 and introduce their principles, characteristics, and progress. In addition, unresolved scientific and technical issues associated with the outlook are presented in this paper.…”

Dual-Encapsulated Nanocomposite for Efficient Thermal Buffering in Heat-Generating Radiative Cooling

“…Among them, the micro-and nanopore structures exhibit remarkable optical properties derived from optimizable size and density for a wide range of applications in personal thermal comfort, energy-efficient green buildings, and wearable devices, 23,24 which can be found in the latest review papers. 25,26 In addition, the promising applications of color radiative cooling 27,28 and dynamic radiative cooling 29,30 have also received a lot of attention.…”

“…Passive radiative cooling (PRC) can spontaneously cool terrestrial objects without external energy source under direct sunlight, offering an innovative path toward outdoor thermal management. , It simultaneously exhibits ultrahigh reflectance in the solar wavelengths (0.3–2.5 μm) and radiate excessive heat through an atmospheric transparency window (ATW, 8–13 μm) to outer cold space (4K) in the form of thermal radiation. , Effective PRC material designs such as micro/nanophotonic structures, − thin films, − coatings, − textiles, − and biomimetic materials − have been widely investigated and even realize subambient cooling performance. Among them, the micro- and nanopore structures exhibit remarkable optical properties derived from optimizable size and density for a wide range of applications in personal thermal comfort, energy-efficient green buildings, and wearable devices, , which can be found in the latest review papers. , In addition, the promising applications of color radiative cooling , and dynamic radiative cooling , have also received a lot of attention.…”