µm) and emitting thermal radiation into the chilly outer space through the atmospheric transparency window (8-13 µm). [3][4][5][6][7][8] To achieve desired cooling effect, PDRC structures should possess a sufficiently high solar reflectance (R solar ) to minimize the heat gain from the environment and a superior long-wave IR emittance (ε LWIR ) for releasing excess heat to the cold outer space. [9][10][11] A variety of PDRC coolers have been proposed and exhibit efficient cooling effect. [12][13][14][15][16][17][18][19][20] Raman et al. [16] presented a nanophotonic structured PDRC cooler consisting of seven alternating layers of hafnium dioxide (HfO 2 ) and silica (SiO 2 ), which could cool the rooftop 4.9 °C below ambient air temperature under direct sunlight irradiation (>850 W m −2 ). Zhai et al. [19] reported a randomized glass-polymer hybrid PDRC film by embedding SiO 2 microspheres in the polymethylpentene matrix and backing the film with a silver coating. It is claimed the prepared PDRC film exhibited a noontime radiative cooling power of 93 W m −2 under direct sunshine. Furthermore, textile as a high-strength flexible material has received widespread attention in many fields. [21,22] Some radiative cooling textiles have also been successfully prepared. Wang et al. [23] presented an electrospinning method to fabricate the flexible membrane radiator, which consists of polyvinylidene fluoride/tetraethyl orthosilicate fibers and SiO 2 microspheres randomly distributed across its surface. Cai et al. [24] reported a spectrally selective nanocomposite textile for radiative outdoor cooling by embedding zinc oxide (ZnO) nanoparticles into polyethylene (PE). Zeng et al. [25] developed a multilayer PDRC metafabric which could cool a human body ≈4.8 °C lower than that covered by a regular cotton fabric in the practical application tests. These PDRC systems show reliable daytime radiative cooling performance. However, most of the PDRC devices suffer from complex preparation process and high cost.Besides radiative cooling, evaporative cooling is also an effective alternative to achieve passive cooling by dissipating heat through water evaporation. Evaporative cooling is a simple, inexpensive, and green strategy to cool the human and buildings without additional energy input. [26][27][28] Li et al. [29] reported an evaporative cooling fabric by integrating superabsorbent
Solar‐driven interfacial water evaporation is a promising strategy to produce clean water by effectively converting abundant solar energy into localized heat. However, many previously reported interfacial evaporation systems are separate and costly. In this work, an all‐in‐one interfacial water evaporator with flexibility, low‐cost, and large‐scale production based on electrostatic flocking technology is proposed. Hydrophilic microfibers (flocks) are vertically planted on the upper side of the textile substrate to enhance the light trapping for photothermal conversion and lower the latent heat for more efficient evaporation. On the other side of the textile, a highly dense and vertically aligned array of hydrophobic flocks are prepared to form a continuous air layer, reducing heat conduction from absorber to bulk water. Taking advantage of those features, the all‐in‐one evaporator achieves a good evaporation rate of 1.32 kg m−2 h−1 for pure water and 1.10 kg m−2 h−1 for seawater. Simultaneously, the evaporator demonstrates resistance to salt accumulation, resulting in its stability in brine. This all‐in‐one evaporator represents an innovative way for designing interfacial evaporators and a convenient approach to mitigate the global freshwater scarcity.
Passive daytime radiative cooling (PDRC) has attracted great attention recently due to its high potential for reducing global energy consumption. However, PDRC materials are easily contaminated in practical applications, which will seriously attenuate their long-term cooling performance. In this work, a multilayered PDRC fabric that is composed of polydimethylsiloxane (PDMS), polymethyl methacrylate (PMMA), and cotton is shown. This multilayered fabric displays a high solar reflectivity (0.94) and an appropriate atmospheric window emissivity (0.79). A practical application test demonstrates the glass covered by this PDRC fabric can lower the temperature up to 7.8 °C under a solar intensity of ≈495 W m −2 . Meanwhile, the multilayered PDRC fabric exhibits self-cleaning property due to its high water contact angle of 118°. Rolling water can effectively remove the contaminants on the fabric surface. It is believed that this multilayered fabric is a promising material to alleviate the energy crisis and reduce greenhouse gas emissions.
Fabrics with efficient evaporative cooling performance not only improve personal thermal comfort but also show essential significance in energy‐saving. This study reports an integrated cooling fabric based on the weft‐back weave structure. By adjusting the type of warp and weft yarns, water absorbency and wettability of the fabric can be altered to achieve the regulation of the fabric's performance. The prepared single‐sided superabsorbent cooling fabric (S‐SAF) shows a water absorbency of 370% and a water retention time of 90 min. S‐SAF can efficiently reduce the indoor temperature of a simulated building by about 6 °C under the radiation of 200 W m−2, and the cooling time is extended up to 150 min. Meanwhile, S‐SAF shows excellent evaporative cooling for the human body and exhibits good recyclability. Therefore, the prepared cooling fabric achieves thermal comfort under a hot and dry environment and has broad application prospects in person and building cooling.
The utilization of solar energy to make human lives better has been one of the primary and green approaches adopted by ordinary people and researchers for decades. This approach has recently gained a lot of attention as a way to tackle clean water scarcity in remote areas. Costly components, complex manufacturing procedures with rarely available equipment, and a surface to condense water vapors are challenges in the way of its application in the required areas. Here, we propose a complete system to solve this problem with a handmade light absorber and a superhydrophilic surface (antifogging) to get vapors back to collect clean water. Our handmade flower-like light absorber stitched by crochet work, the single stitch method, was able to get a decent evaporation rate of 1.75 kg/m 2 ·h in pure water and slightly lower rates of 1.62 and 1.65 kg/m 2 ·h with brine and pond water, respectively. Still, our proposed superhydrophilic coated surface can collect ∼37% more water than the pristine surface. This system has a huge potential for use in rural areas because of multiple key advantages, such as simple technology, readily available low-cost raw materials, and easy fabrication.
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