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Chao Jia

Bio: Chao Jia is an academic researcher from Tsinghua University. The author has contributed to research in topics: Materials science & Nanofiber. The author has an hindex of 28, co-authored 49 publications receiving 3860 citations. Previous affiliations of Chao Jia include University of Maryland, College Park & Beijing Institute of Technology.

Papers published on a yearly basis

Papers
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Journal ArticleDOI
TL;DR: The nature-inspired design concept in this study is straightforward and easily scalable, representing one of the most promising solutions for renewable and portable solar energy generation and other related phase-change applications.
Abstract: Solar steam generation with subsequent steam recondensation has been regarded as one of the most promising techniques to utilize the abundant solar energy and sea water or other unpurified water through water purification, desalination, and distillation. Although tremendous efforts have been dedicated to developing high-efficiency solar steam generation devices, challenges remain in terms of the relatively low efficiency, complicated fabrications, high cost, and inability to scale up. Here, inspired by the water transpiration behavior of trees, the use of carbon nanotube (CNT)-modified flexible wood membrane (F-Wood/CNTs) is demonstrated as a flexible, portable, recyclable, and efficient solar steam generation device for low-cost and scalable solar steam generation applications. Benefitting from the unique structural merits of the F-Wood/CNTs membrane-a black CNT-coated hair-like surface with excellent light absorbability, wood matrix with low thermal conductivity, hierarchical micro- and nanochannels for water pumping and escaping, solar steam generation device based on the F-Wood/CNTs membrane demonstrates a high efficiency of 81% at 10 kW cm-2 , representing one of the highest values ever-reported. The nature-inspired design concept in this study is straightforward and easily scalable, representing one of the most promising solutions for renewable and portable solar energy generation and other related phase-change applications.

616 citations

Journal ArticleDOI
TL;DR: The 3D-printed porous evaporator with intrinsic low thermal conductivity enables heat localization and effectively alleviates thermal dissipation to the bulk water and has a high solar steam efficiency under 1 sun illumination, among the best compared with other reported evaporators.
Abstract: Using solar energy to generate steam is a clean and sustainable approach to addressing the issue of water shortage. The current challenge for solar steam generation is to develop easy-to-manufacture and scalable methods which can convert solar irradiation into exploitable thermal energy with high efficiency. Although various material and structure designs have been reported, high efficiency in solar steam generation usually can be achieved only at concentrated solar illumination. For the first time, 3D printing to construct an all-in-one evaporator with a concave structure for high-efficiency solar steam generation under 1 sun illumination is used. The solar-steam-generation device has a high porosity (97.3%) and efficient broadband solar absorption (>97%). The 3D-printed porous evaporator with intrinsic low thermal conductivity enables heat localization and effectively alleviates thermal dissipation to the bulk water. As a result, the 3D-printed evaporator has a high solar steam efficiency of 85.6% under 1 sun illumination (1 kW m-2 ), which is among the best compared with other reported evaporators. The all-in-one structure design using the advanced 3D printing fabrication technique offers a new approach to solar energy harvesting for high-efficiency steam generation.

511 citations

Journal ArticleDOI
TL;DR: The tree-inspired design offers an inexpensive and scalable solar energy harvesting and steam generation technology that can provide clean water globally, especially for rural or remote areas where water is not only scarce but also limited by water extraction materials and methods.
Abstract: The solar steam process, akin to the natural water cycle, is considered to be an attractive approach to address water scarcity issues globally. However, water extraction from groundwater, for example, has not been demonstrated using these existing technologies. Additionally, there are major unaddressed challenges in extracting potable water from seawater including salt accumulation and long-term evaporation stability, which warrant further investigation. Herein, a high-performance solar steam device composed entirely of natural wood is reported. The pristine, natural wood is cut along the transverse direction and the top surface is carbonized to create a unique bilayer structure. This tree-inspired design offers distinct advantages for water extraction, including rapid water transport and evaporation in the mesoporous wood, high light absorption (≈99%) within the surface carbonized open wood channels, a low thermal conductivity to avoid thermal loss, and cost effectiveness. The device also exhibits long-term stability in seawater without salt accumulation as well as high performance for underground water extraction. The tree-inspired design offers an inexpensive and scalable solar energy harvesting and steam generation technology that can provide clean water globally, especially for rural or remote areas where water is not only scarce but also limited by water extraction materials and methods.

443 citations

Journal ArticleDOI
TL;DR: In this paper, a bimodal porous structure (e.g., balsa wood) was used as an efficient and stable solar vapor generator for high-salinity brine desalination.
Abstract: The shortage of clean water is one of the predominant causes of human mortality, especially in remote rural areas. Currently, solar steam generation is being adopted as an efficient, sustainable, and low-cost means for water desalination to produce clean water. However, preventing salt accumulation during operation while maintaining long-term stability and a rapid evaporation rate is a critical challenge that needs to be urgently addressed to further facilitate the practical applications of solar desalination, especially for desalinating high-salinity brine. Here, we demonstrate that a bimodal porous structure (e.g., balsa wood) can serve as an efficient and stable solar vapor generator for high-salinity brine desalination. Taking advantage of the inherent bimodal porous and interconnected microstructures of balsa wood, rapid capillary transport through the microchannels and efficient transport between the micro- and macrochannels through ray cells and pits in the bimodal evaporator can lead to quick replenishment of surface vaporized brine to ensure fast and continuous clean water vapor generation. The bimodal evaporator demonstrates a rapid evaporation rate of 6.4 kg m−2 h−1 under 6 suns irradiation and outstanding long-term stability for desalination of high salinity brine. The large vessel channels play a critical role in preventing salt from accumulating, as evidenced by controlled experiments with large vessels either blocked in the bimodal evaporator (balsa evaporator) or absent in a unimodal evaporator (e.g., cedar wood) whose porous structure occurs naturally without large vessels. Both approaches demonstrate severe salt accumulation during solar desalination due to a lack of sufficient brine replenishment from the bulk solution beneath. With its unique bimodal porous and interconnected microstructure configuration obtained by a facile and scalable fabrication method, our bimodal porous structured evaporator device represents an efficient, stable, low-cost, and environmentally friendly solar vapor generator for high-salinity brine desalination.

409 citations

Journal ArticleDOI
TL;DR: In this article, a solar steam generation device is designed utilizing crossplane water transport in wood via nanoscale channels and the preferred thermal transport direction is decoupled to reduce the conductive heat loss.
Abstract: Solar steam generation is regarded as one of the most sustainable techniques for desalination and wastewater treatment. However, there has been a lack of scalable material systems with high efficiency under 1 Sun. A solar steam generation device is designed utilizing crossplane water transport in wood via nanoscale channels and the preferred thermal transport direction is decoupled to reduce the conductive heat loss. A high steam generation efficiency of 80% under 1 Sun and 89% under 10 Suns is achieved. Surprisingly, the crossplanes perpendicular to the mesoporous wood can provide rapid water transport via the pits and spirals. The cellulose nanofibers are circularly oriented around the pits and highly aligned along spirals to draw water across lumens. Meanwhile, the anisotropic thermal conduction of mesoporous wood is utilized, which can provide better insulation than widely used superthermal insulator Styrofoam (≈0.03 W m−1 K−1). The crossplane direction of wood exhibits a thermal conductivity of 0.11 W m−1 K−1. The anisotropic thermal conduction redirects the absorbed heat along the in-plane direction while impeding the conductive heat loss to the water. The solar steam generation device is promising for cost-effective and large-scale application under ambient solar irradiance.

388 citations


Cited by
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01 May 1993
TL;DR: Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems.
Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

29,323 citations

Journal ArticleDOI
TL;DR: Tao et al. as discussed by the authors discuss the development of the key components for achieving high-performance evaporation, including solar absorbers and structures, thermal insulators and thermal concentrators.
Abstract: As a ubiquitous solar-thermal energy conversion process, solar-driven evaporation has attracted tremendous research attention owing to its high conversion efficiency of solar energy and transformative industrial potential. In recent years, solar-driven interfacial evaporation by localization of solar-thermal energy conversion to the air/liquid interface has been proposed as a promising alternative to conventional bulk heating-based evaporation, potentially reducing thermal losses and improving energy conversion efficiency. In this Review, we discuss the development of the key components for achieving high-performance evaporation, including solar absorbers, evaporation structures, thermal insulators and thermal concentrators, and discuss how they improve the performance of the solar-driven interfacial evaporation system. We describe the possibilities for applying this efficient solar-driven interfacial evaporation process for energy conversion applications. The exciting opportunities and challenges in both fundamental research and practical implementation of the solar-driven interfacial evaporation process are also discussed. The thermal properties of solar energy can be exploited for many applications, including evaporation. Tao et al. review recent developments in the field of solar-driven interfacial evaporation, which have enabled higher-performance structures by localizing energy conversion to the air/liquid interface.

1,139 citations

Journal ArticleDOI
TL;DR: In this article, the authors provide a comprehensive review on the current development in efficient photothermal evaporation, and suggest directions to further enhance its overall efficiency through the judicious choice of materials and system designs, while synchronously capitalizing waste energy to realize concurrent clean water and energy production.
Abstract: Photothermal materials with broad solar absorption and high conversion efficiency have recently attracted significant interest. They are becoming a fast-growing research focus in the area of solar-driven vaporization for clean water production. The parallel development of thermal management strategies through both material and system designs has further improved the overall efficiency of solar vaporization. Collectively, this green solar-driven water vaporization technology has regained attention as a sustainable solution for water scarcity. In this review, we will report the recent progress in solar absorber material design based on various photothermal conversion mechanisms, evaluate the prerequisites in terms of optical, thermal and wetting properties for efficient solar-driven water vaporization, classify the systems based on different photothermal evaporation configurations and discuss other correlated applications in the areas of desalination, water purification and energy generation. This article aims to provide a comprehensive review on the current development in efficient photothermal evaporation, and suggest directions to further enhance its overall efficiency through the judicious choice of materials and system designs, while synchronously capitalizing waste energy to realize concurrent clean water and energy production.

1,061 citations

Journal ArticleDOI
24 May 2019-Science
TL;DR: By a process of complete delignification and densification of wood, a structural material with a mechanical strength of 404.3 megapascals is developed, more than eight times that of natural wood, resulting in continuous subambient cooling during both day and night.
Abstract: Reducing human reliance on energy-inefficient cooling methods such as air conditioning would have a large impact on the global energy landscape. By a process of complete delignification and densification of wood, we developed a structural material with a mechanical strength of 404.3 megapascals, more than eight times that of natural wood. The cellulose nanofibers in our engineered material backscatter solar radiation and emit strongly in mid-infrared wavelengths, resulting in continuous subambient cooling during both day and night. We model the potential impact of our cooling wood and find energy savings between 20 and 60%, which is most pronounced in hot and dry climates.

710 citations

Journal ArticleDOI
20 Mar 2019-Joule
TL;DR: In this article, a review of recent developments in photothermal materials, with a focus on their photothermal conversion mechanisms as light absorbers, is presented, and the potential applications of this attractive technology in a variety of energy and environmental fields are described.

690 citations