29 results on '"Li, Chaoen"'
Search Results
2. SnO2 coupled cobalt pyrite for Hg0 removal from simulated flue gas
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Li, Chaoen, Wu, Jiang, and Liu, Dongjing
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- 2023
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3. Energy performance of buildings with composite phase-change material wallboards in different climatic zones of China
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Li, Chaoen, Wen, Xiaodong, Cai, Wei, Wu, Jiayu, Shao, JingJing, Yang, Yikun, Yu, Hang, Liu, Dongjing, and Wang, Meng
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- 2022
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4. Constructing 3D Bi/Bi4O5I2 microspheres with rich oxygen vacancies by one-pot solvothermal method for enhancing photocatalytic activity on mercury removal
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Chen, Liping, Li, Chaoen, Zhao, Yanfeng, Wu, Jiang, Li, Xiaokun, Qiao, Zhanwei, He, Ping, Qi, Xuemei, Liu, Zhenhao, and Wei, Guoqing
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- 2021
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5. Prioritizing urban planning factors on community energy performance based on GIS-informed building energy modeling
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Yu, Hang, Wang, Meng, Lin, Xiaoyu, Guo, Haijin, Liu, He, Zhao, Yingru, Wang, Hongxin, Li, Chaoen, and Jing, Rui
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- 2021
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6. Liquefied synthetic methane from ambient CO2 and renewable H2 - A technoeconomic study
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Kiani, Ali, Lejeune, Michael, Li, Chaoen, Patel, Jim, and Feron, Paul
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- 2021
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7. Novel carbon-based sorbents for elemental mercury removal from gas streams: A review
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Liu, Dongjing, Li, Chaoen, Wu, Jiang, and Liu, Yangxian
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- 2020
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8. Experimental investigation of thermal performance of microencapsulated PCM-contained wallboard by two measurement modes
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Li, Chaoen, Yu, Hang, and Song, Yuan
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- 2019
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9. Photocatalytic oxidation of gas-phase Hg0 by carbon spheres supported visible-light-driven CuO–TiO2
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Wu, Jiang, Li, Chaoen, Chen, Xiantuo, Zhang, Jing, Zhao, Lili, Huang, Tianfang, Hu, Tao, Zhang, Chong, Ni, Bu, Zhou, Xiao, Liang, Pankun, and Zhang, Wenbo
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- 2017
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10. Photocatalytic oxidation of gas-phase Hg0 by CuO/TiO2
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Wu, Jiang, Li, Chaoen, Zhao, Xuying, Wu, Qiang, Qi, Xuemei, Chen, Xiantuo, Hu, Tao, and Cao, Yan
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- 2015
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11. Pyrolysis of rice husk in molten lithium chloride: Biochar structure evolution and CO2 adsorption.
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Li, Bin, Li, Mangmang, Xie, Xing, Li, Chaoen, and Liu, Dongjing
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CARBON sequestration ,RICE hulls ,BIOCHAR ,LITHIUM chloride ,PYROLYSIS - Abstract
Biochars are attained by direct pyrolysis of the mixture of rice husk (RH) powders and lithium chloride within 600–800 °C. The physical and chemical properties of RH biochars are studied using diverse characterization techniques. Effects of pyrolysis temperature and salt/biomass ratio on the structure properties and CO 2 adsorption performances of RH biochars are tested at 25 °C and 100 kPa. The results show that the CO 2 uptakes of RH biochars first ascend and then descend with incremental pyrolysis temperature and basically increase with the elevation of the salt/biomass ratio. The biochar prepared at 700 °C with the salt/biomass ratio of 7.5 in an air atmosphere presents the highest CO 2 uptake of 2.70 mmol/g, which is much higher than the one (1.98 mmol/g) obtained at 700 °C without addition of LiCl salts in a nitrogen stream mainly due to its bigger specific surface area, higher contents of chemisorbed oxygen and carbon defect structures. Pyrolysis of rice husk in molten LiCl can effectively improve the porosity and the surface functionality of the biochar, thereby enhancing its CO 2 capture performance. • Biochars are prepared using molten salt pyrolysis method in an air atmosphere. • Molten LiCl can improve the physical and chemical property of rice husk biochar. • Temperature and salt greatly affect the structure and CO 2 adsorption of biochar. • Molten salt biochar visibly outperformed common biochar toward CO 2 adsorption. [ABSTRACT FROM AUTHOR]
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- 2024
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12. Recent trend in thermal catalytic low temperature CO2 methanation: A critical review.
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Lee, Woo Jin, Li, Chaoen, Prajitno, Hermawan, Yoo, Jiho, Patel, Jim, Yang, Yunxia, and Lim, Seng
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LOW temperatures , *METHANATION , *CARBON dioxide , *GREENHOUSE gases , *HIGH temperatures , *HYDROGEN production - Abstract
[Display omitted] • First comprehensive overview on low temperature CO 2 methanation. • Overview on CO 2 methanation fundamentals, catalysts and reactor technologies. • Identified challenges and opportunities in each of the areas reviewed. • A critical process simulation result for low temperature CO 2 methanation. CO 2 utilization technologies can not only provide a pathway to reduce greenhouse gas emissions but may also enable renewable energy to be incorporated into important materials used in the society such as fuel and chemicals. Power to gas (PtG) technologies, especially Power to methane has been deemed as one of the promising pathways for the conversion of CO 2 into valuable gaseous fuel. Many reports have reviewed the academic literature related to CO 2 methanation. While the benefits of high temperature methanation for overall process efficiency are well understood, the potential for low-temperature methanation is less understood. In particular the opportunities that arise from coupling a low-temperature methanation process with low temperature hydrogen production technologies, such as PEM electrolysis, have received little attention. It is therefore considered valuable to provide a critical review of the state of the art of this technology at low temperature conditions for the interests of broader research community. In this paper we focus on the recent work around low temperature CO 2 methanation including reaction thermodynamics and kinetics, catalyst materials including supports and promoters, and suitable reactor technologies. We discuss each of these critical aspects of the technology and identify key challenges and opportunities for low temperature CO 2 methanation (methanation conducted at temperatures less than 300 °C). As part of this paper, we also present the results of an ASPEN Plus simulation study based on data available from the literature to highlight the potential energy efficiency gains of a low temperature methanation process. [ABSTRACT FROM AUTHOR]
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- 2021
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13. Novel metal sulfide sorbents for elemental mercury capture in flue gas: A review.
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Liu, Dongjing, Li, Chaoen, Jia, Tao, Wu, Jiang, and Li, Bin
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METAL sulfides , *FLUE gases , *PYRITES , *MERCURY , *SORBENTS , *MERCURY (Planet) , *SULFUR dioxide - Abstract
• Various synthetic methods for metal sulfides are introduced and compared. • Performances, merits, and flaws of metal sulfides are summarized and commented. • Layered metal sulfides, MoS 2 , WS 2 and SnS 2 , are the most promising mercury sorbents. • Effects of gas ingredients on the performances of metal sulfides are summed up. • Mercury capture mechanisms for metal sulfides are outlined and discussed. Mercury is largely emitted into the atmosphere during fossil fuel combustion or gasification, which causes a long-term contamination problem and poses great threats to human health. Currently, novel metal sulfides have been extensively investigated in capturing gaseous mercury because of their intense Hg0 affinities, large mercury uptakes, and distinguished tolerance to sulfur dioxide. This article overviews the recent progress on elemental mercury capture by diverse metal sulfides, i.e., CuS, ZnS, pyrite-phase metal sulfides, layered metal sulfides, Bi 2 S 3 and In 2 S 3. CuS and ZnS show good performances in a narrow temperature range due to the poor thermal stability and the compact crystal structure, respectively. Bi 2 S 3 and In 2 S 3 are also active in Hg0 adsorption, however, their performances are still unsatisfactory. Most pyrite-phase metal sulfides show moderate Hg0 capture abilities likely due to their compact crystal structures. Loading pyrites onto carriers or creating S vacancies in pyrite lattices seem to be feasible pathways to improve their performances. MoS 2 and WS 2 attained via molten salt method significantly outperform the ones obtained via hydrothermal method at elevated temperatures due to the production of ample sulfur variances and chemisorbed oxygen. Incorporating heteroatoms and expanding the interlayer distance by ions intercalation are effective routes to further strengthen their performances probably due to promoted electron transfer and increased accessibility of active sites, respectively. [ABSTRACT FROM AUTHOR]
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- 2024
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14. A n-octadecane/hierarchically porous TiO2 form-stable PCM for thermal energy storage.
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Li, Chaoen, Yu, Hang, Song, Yuan, Wang, Meng, and Liu, Zhiyuan
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HEAT storage , *PULSE-code modulation , *CHEMICAL bonds , *PHASE change materials , *NANOPOROUS materials , *LATENT heat , *INTERFACIAL tension , *TRANSMISSION electron microscopes - Abstract
For a phase-change material (PCM) confined in a porous structure, the interfacial interactions between the PCM and the porous skeleton are the decisive factors in latent heat storage performance. In this work, a novel composite PCM based on hierarchically porous TiO 2 and n-octadecane was successfully synthesized. The porous TiO 2 was prepared by a soft-template method, and the composite PCM was fabricated by introducing n-octadecane under vacuum. Transmission electron microscope and X-ray diffraction (XRD) results revealed that the as-prepared supporting matrix was crystalline TiO 2 , and N 2 adsorption/desorption isotherms indicated that TiO 2 has a hierarchically porous structure. For composite PCMs, Fourier transform infrared spectroscopy and XRD spectra revealed that no chemical bonds were formed between n-octadecane and TiO 2. Scanning electron microscopy results showed abundant n-octadecane enclosed within the nanopores and closely bound on the surfaces of the hierarchically porous TiO 2 , as a result of capillary forces and interfacial tension. Porous TiO 2 exhibited high adsorption for n-octadecane (50 wt%), and the relative enthalpy of the composite PCM was as high as 85.8 J/g. Compared with pure n-octadecane, the thermal conductivity of the as-prepared composite PCMs (e.g., 50 wt% n-octadecane sample) was improved by 138% with the addition of porous TiO 2. After 800 melting/solidifying cycles, the composite PCMs exhibited excellent thermal reliability and high enthalpy. The influence of the TiO 2 pore structure on n-octadecane crystallization behavior is shown in the results. • Hierarchically porous TiO 2 nanomaterial provided an ideal skeleton. • A novel n-octadecane/hierarchically porous TiO 2 composite PCMs was synthesized. • The effect of the nanoporous structure on crystallization is demonstrated. [ABSTRACT FROM AUTHOR]
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- 2020
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15. Novel hybrid microencapsulated phase change materials incorporated wallboard for year-long year energy storage in buildings.
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Li, Chaoen, Yu, Hang, Song, Yuan, and Liu, Zhiyuan
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WALLBOARD , *ENERGY consumption of buildings , *PHASE change materials , *MICROENCAPSULATION , *ENERGY storage , *THERMAL comfort - Abstract
Graphical abstract Highlights • A 3-layer phase change material configuration was proposed. • A method for temperature selection of phase change material was proposed. • Novel hybrid phase change material wallboards were fabricated and characterized. Abstract Phase change materials are smart, feasible latent heat storage materials and have been incorporated into building materials to reduce energy demand and improve the thermal comfort of buildings. This study proposes a method for improving energy efficiency and thermal comfort in buildings (during both summers and winters) by developing a novel hybrid phase change material wallboard and a method to select the temperature of phase change material for different seasons (29 °C for summer, 18 °C for midseason, and 12 °C for winter). This type of hybrid phase change materials wallboard consists of three types of phase change materials with different phase-change temperatures that can be utilized efficiently in different seasons. The thermal performances of the hybrid phase change material wallboards (two combination modes: Mode1 and Mode2) were evaluated by a guarded hot plate method. The effective thermal conductivity (λ) and apparent specific heat (C p) of these wallboards were investigated. The interior temperature variations of the two types of phase change materials wallboards were compared during heating and cooling, and it could be concluded that the Mode2 hybrid phase change materials wallboard (where phase change material was incorporated into different gypsum wallboard layers) was more suitable for real applications. The goal of this study is to investigate an appropriate method to fabricate a new hybrid phase change materials wallboard for building energy savings over different seasons. [ABSTRACT FROM AUTHOR]
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- 2019
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16. Preparation and characterization of PMMA/TiO2 hybrid shell microencapsulated PCMs for thermal energy storage.
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Li, Chaoen, Yu, Hang, Song, Yuan, Liang, Hao, and Yan, Xun
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POLYMETHYLMETHACRYLATE , *TITANIUM dioxide , *MICROENCAPSULATION , *HEAT storage , *EMULSIONS - Abstract
Abstract A novel n-octadecane@PMMA/TiO 2 hybrid shell PCM was prepared through a facile emulsion method, then characterized and estimated for thermal energy storage. During the synthetic process, the emulsion was enhanced by modified TiO 2 particles to improve the stability and thermal conduction. The aggregation process can be performed by an eco-friendly and efficient way, which was carried out under ultraviolet radiation for 10 min at 35 °C. The prepared microencapsulated PCMs have excellent nuclear shell structure, and the surface of the shell covered with TiO 2 particles uniformly. The TGA and DSC analysis showed that the microencapsulated PCMs have excellent thermal stability, high enthalpy and small degree of supercooling, which were suitable for thermal energy release and retrieval. The encapsulation efficiency of the microcapsules reached 67.2% when the appropriate proportion of MMA/n-octadecane was 1:1, and the melting enthalpy was 179.9 J/g. We also studied the crystallization behavior by in situ XRD method, the results showed that the crystallization behavior was different comparing with the bulk n-octadecane and hybrid shell PCMs. During the crystallization process, surface crystallization phenomenon occurred on the interface, which existed between inner surface of the microcapsules and melted n-octadecane. Subsequently, two sequential exothermic peaks were formed, which was different with bulk n-octadecane (only one exothermic peaks). The work was not only to develop a method to prepare the organic-inorganic hybrid shell Micro-PCMs, but also to study the discipline of crystallization behavior between the bulk n-octadecane and hybrid shell PCMs. Highlights • N-octadecane@PMMA/TiO 2 PCM was prepared through a facile efficient method. • The phase change behavior of composite PCMs was investigated. • The microencapsulated PCM showed excellent thermal performance. [ABSTRACT FROM AUTHOR]
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- 2019
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17. Synthesis of microencapsulated stearic acid with amorphous TiO2 as shape-stabilized PCMs for thermal energy storage.
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Li, Chaoen, He, Guixiong, Yan, Huaguang, Yu, Hang, and Song, Yuan
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Abstract Stearic acid/amorphous TiO 2 composites were synthesized by a Sol-gel way with different pH values. The as-prepared PCMs were characterized by XRD, SEM, FTIR to determine the chemical compositions and structure to find out the influence of synthesis condition (pH valves). The thermal performance and thermal stability of the composite phase change material were determined by DSC and TGA. It was found that the composite PCMs prepared in the acidic condition exhibited better than that under alkaline condition. The addition of CNTs enhanced the thermal conductivity of the as-prepared PCMs. The purpose of our study is to provide a sample way to synthesis of composite PCM for thermal energy storage. [ABSTRACT FROM AUTHOR]
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- 2018
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18. Synthesis and characterization of PEG/ZSM-5 composite phase change materials for latent heat storage.
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Li, Chaoen, Yu, Hang, Song, Yuan, and Zhao, Mei
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LATENT heat , *HEAT storage , *ENERGY storage , *HEATS of vaporization , *ETHYLENE glycol - Abstract
A novel poly (ethylene glycol)/ZSM-5 composite was fabricated by a simple way, and it was characterized and evaluated for heat energy storage. The composite PCMs was fabricated through introducing PEG to mesoporous pores of ZSM-5 assisted with a vacuum impregnation system. XRD and FTIR analysis results showed that there was no chemical reaction happened between PEG4000 and ZSM-5. DSC and TGA analysis results indicated that the as-prepared PCMs has outstanding latent heats and superb thermal stability. The latent heat of the as-prepared PCMs achieves to 76.37 J/g without any leakiness. Compare with pure PEG, the thermal conductivity of as-prepared PCMs was improved 200%, which means selecting ZSM-5 serve as the supporting material was an effective way to enhance the thermal conductivity. Exudation stability tests results showed that the doping of PEG can reach up 50 wt% without any leakage when the composite undergoing the melting process. According to the above analysis, the prepared composite with good thermal stability, high latent heats and excellent thermal conductivity is very suitable for heat energy storage. [ABSTRACT FROM AUTHOR]
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- 2018
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19. Immobilization of gaseous elemental mercury using SnS2-Wrapped magnetic Fe3O4 microspheres.
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Liu, Dongjing, Yang, Lingtao, Wu, Jiang, and Li, Chaoen
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IRON oxides ,MICROSPHERES ,MERCURY - Abstract
A SnS 2 @Fe 3 O 4 composite has been easily synthesized via a KSCN fused salt approach and adopted for capturing elemental mercury at low temperature. Calcination temperature significantly impacts the mercury capture performance of SnS 2 -T. The optimal synthesis temperature for SnS 2 -T is 250 °C. Pristine SnS 2 -250 obtained at 250 °C exhibits a moderate Hg
0 adsorption capability with mercury removing efficiency less than 65% within 80–120 °C. Fe 3 O 4 incorporation can notably improve the mercury capture ability of SnS 2 -250 probably due to the cooperative effect between SnS 2 nanoflakes and magnetic Fe 3 O 4 microspheres. SnS 2 -250@Fe 3 O 4 holds a good magnetism (saturation magnetization: 23 emu/g), which performs optimally at 100 °C with Hg0 capture efficiency of 95.2%. Sn4+ , S2− , Fe3+ ions and chemisorbed oxygen species are principal active sites for Hg0 capture over SnS 2 -250@Fe 3 O 4 , which convert adsorbed Hg0 into HgO, HgS, and HgSO 4. • A SnS 2 @Fe 3 O 4 composite has been facilely obtained via a KSCN molten salt method. • Calcination temperature can notably influence the Hg0 capture performance of SnS 2. • SnS 2 nanoflakes and Fe 3 O 4 microspheres may show a synergy toward Hg0 capture. • Fe 3 O 4 addition can evidently enhance the mercury capture ability of tin disulfide. [ABSTRACT FROM AUTHOR]- Published
- 2023
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20. Assessing the impacts of urban morphology factors on the energy performance for building stocks based on a novel automatic generation framework.
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Wang, Meng, Yu, Hang, Yang, Yikun, Jing, Rui, Tang, Yin, and Li, Chaoen
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URBAN morphology ,BUILDING performance ,GEOMETRIC series ,URBAN planning ,GEOMETRIC modeling ,MODULAR construction - Abstract
• Propose a generalized paradigm of neighborhood-scale urban building energy modeling. • Determine the typical building shape through field survey and clustering analysis. • Develop massive geometric prototype models for building stock. • Introduce a series of geometric parameters to describe urban morphology. • Identify the most influential urban morphology factors affecting energy demands. The building sector accounts for an increasing amount of energy and emissions with continued urbanization, and improving the energy performance of building stocks at the early planning stage is cost-efficient and easy to operate. This study presents an automatic generation framework to quantify the impacts of urban morphology factors on the energy performance of neighborhood-scale building stocks. The typical office building shape is firstly determined by a field survey and clustering analysis. Then the building modular cells-based method is introduced to establish a comprehensive energy performance database for building stocks. The impacts of urban morphology factors on energy performance are further prioritized via global sensitivity analysis. A case study in Shanghai, China demonstrated the proposed automatic generation framework which can act as a generalized paradigm to model building stocks and be widely applicable to other climate zones. The urban morphology factors representing buildings' geometric characteristics tend to have greater impacts on energy performance, among which the top influencing factors are relative compactness, building coverage ratio, and building height distribution. The proposed framework and the findings are expected to generate valuable insights into energy-efficient urban design. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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21. Heat treatment of 6H-SiC under different gaseous environments.
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Lee, Woo Jin, Li, Chaoen, Burke, Nick, Patel, Jim, Wilson, Merrill, and Gerdes, Karl
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SILICON carbide , *HEAT treatment of metals , *CHEMICAL processes , *MASS transfer , *METALLIC surfaces - Abstract
Abstract: Silicon carbide is a useful material for the reactors in chemical processes. In recent years, microreactors have gained significant attentions due to the high demand for process miniaturization. As heat and mass-transfer are highly improved inside the gas flow channels in microreactors, any change on the surface of inner channels under heating becomes critical to the performance of microreactors. To investigate the surface changes of silicon carbide during the heat treatment, 6H-SiC coupons were processed in five different gases—Ar, N2, air, 0.9% O2 in Ar and 50% H2O in air—that are commonly encountered in high temperature chemical processes. While the formation of oxide film was found to be dependent on the partial pressure of oxidizing gas, surface decomposition was found from the treatment in nitrogen environment. Characterization of the SiC surface by Raman spectroscopy and SEM–EDX revealed that a graphitic layer has formed at the oxide film/SiC interface. Crystallinity of graphitic layer at the interface seemed to be dependent on the partial pressure of oxidizing gas, which was revealed by the relationship between G peak position and R(I D/I G). The intensity ratio of FTO(0)/FTO(2/6) bands showed that stacking faults on the surface of SiC coupons were reduced after heat treatment. [Copyright &y& Elsevier]
- Published
- 2014
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22. A database of clothing overall and local insulation and prediction models for estimating ensembles' insulation.
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Tang, Yin, Su, Zixiong, Yu, Hang, Zhang, Kege, Li, Chaoen, and Ye, Hai
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PREDICTION models ,THERMAL comfort ,LINEAR equations ,HUMAN ecology ,HEAT transfer ,FORECASTING - Abstract
Clothing has a significant impact on the heat transfer between the human body and the environment, and clothing insulation is an important input parameter for many thermal comfort models. With the development of studies on non-uniform environment and human's local thermal comfort, the clothing local insulation is required in the multi-node human thermoregulation models and significantly affects the accuracy of simulation results. However, there lacks data on clothing local insulation values in standards. In this study, the local insulation of 57 typical garments and 62 ensembles with different layers (1–6 layers) were measured using a thermal manikin. The results show that the ranges of overall insulation for tested garments and ensembles were 0.01–0.56 clo and 0.27–2.17 clo, respectively. The local insulation values differed greatly from the overall insulation values, and varied greatly between different body parts. Further, the linear regression was performed between the ensembles' local insulation at different body parts and the sum of the garments' local insulation. Based on the prediction equations of local insulation, a new method for estimating the overall insulation of ensembles was proposed. Compared with the tradition method using the linear regression equations of overall insulation, the new method reduced the mean relative error from 12.6%–9.1% to 3.4%. This study provided basic data and prediction equations of local insulation for future researches of clothing insulation and local thermal comfort. • A clothing local insulation database including 57 typical garments and 62 ensembles was built. • Linear regression equations of local insulation at different body parts were proposed. • A new method for predicting overall insulation of ensembles using garments' local insulation was developed. • New method reduced the MAPE from 9.1% to 3.4% compared with the method using linear model of overall insulation. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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23. Typical winter clothing characteristics and thermal insulation of ensembles for older people in China.
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Tang, Yin, Yu, Hang, Wang, Zi, Luo, Maohui, Zhang, Kege, Jiao, Yu, and Li, Chaoen
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OLDER people ,THERMAL insulation ,THERMAL comfort ,COLD weather clothing ,SKIN temperature - Abstract
Clothing plays an essential role in maintaining heat balance and thermal comfort for older people but varies with climate conditions and costume culture. The recommended clothing insulation in ISO 7730 and ASHRAE Standard 55 lack information on typical clothing ensemble and local insulation values for older people. To investigate the winter clothing characteristics of older people living in Shanghai, a field survey involving 342 healthy subjects from 12 aged-care homes and a lab study conducted with a 22-segment thermal manikin were performed. Subjects' typical clothing ensembles were summarized based on the survey. The local clothing insulation of 34 typical garments and 35 clothing ensembles were measured in the lab experiment. Results show that most older people in winter worn 7 pieces of clothes (excluding underpants, socks and shoes). The frequencies of typical upper and lower garments/ensembles were reported. Through manikin tests, the whole and local insulation of those typical garments and ensembles were presented. By comparison, the insulation values of garments in ISO 7730 were found to be inconsistent with tested garments' results for older people. Further, linear regression models were built to link relationships of the insulation of multiple garments and ensembles. Through running an older people-based thermoregulation model, it was found an incorrect estimation of typical winter clothing insulation for older people could lead around 1.3 °C deviation on predicted mean skin temperature or around 26% deviation on heat loss. • A field study of 342 elderly people was conducted in 12 aged-care homes in winter. • Local insulation of typical ensembles was tested using a 22-segment thermal manikin. • A winter local clothing insulation database for ederly people was built. • Linear regression models of local clothing insulation were established. • Effects of typical winter clothing for the elderly in predicting skin temperature have been discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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24. Unveiling the structural transitions during activation of a CO2 methanation catalyst Ru0/ZrO2 synthesised from a MOF precursor.
- Author
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Lippi, Renata, D'Angelo, Anita M., Li, Chaoen, Howard, Shaun C., Madsen, Ian C., Wilson, Karen, Lee, Adam F., Sumby, Christopher J., Doonan, Christian J., Patel, Jim, and Kennedy, Danielle F.
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METHANATION , *METAL activation , *METHANE as fuel , *CARBON dioxide , *HEAT exhaustion , *CATALYSTS - Abstract
[Display omitted] • H 2 and CO 2 mixture essential for thermal MOF-derivation of Ru0/ZrO 2. • H 2 acts by breaking down the MOF framework and by reducing Ru atoms. • CO 2 acts as a mild oxidant promoting carbon removal. • In operando powder XRD elucidated phase transition from MOF into active catalyst. Carbon Capture, Utilisation and Storage (CCUS) technologies are utilised to minimise net CO 2 emissions and hence mitigate the impact of anthropogenic emissions on the global climate. One example of CO 2 utilisation is the production of carbon-neutral methane fuel via catalytic CO 2 reduction with H 2 (methanation). Thermal activation of a metal impregnated metal-organic framework (MOF), 1 wt%Ru/UiO-66 in the presence of H 2 and CO 2 provides in situ synthesis of a highly active methanation catalyst: H 2 promotes the formation of Ru0 nanoparticles, and CO 2 behaves as a mild oxidant to remove framework carbon and promote ZrO 2 crystallisation. The nature of the active MOF-derived Ru0/ZrO 2 catalyst was studied by PXRD, TEM, and XAS, and the evolution of the parent 1 wt%Ru/UiO-66 during thermal activation monitored in operando by synchrotron PXRD. The Ru impregnated Zr-based MOF collapses on heating in H 2 and CO 2 to form an amorphous C and Zr containing phase that subsequently crystallises as tetragonal (t-) ZrO 2 nanoparticles. These t-ZrO 2 nanoparticles undergo a subsequent phase transition to the more stable monoclinic (m-) ZrO 2 polymorph. In situ activation of Ru/UiO-66 generates a highly active catalyst for CO 2 methanation by transforming the MOF precursor into a (carbon-free) crystalline t-ZrO 2 support that stabilises highly dispersed metallic Ru nanoparticles. This insight may guide the rational design of future MOF-derived catalysts. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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25. Predicting the energy consumption in buildings using the optimized support vector regression model.
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Cai, Wei, Wen, Xiaodong, Li, Chaoen, Shao, Jingjing, and Xu, Jianguo
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ENERGY consumption forecasting , *ENERGY consumption of buildings , *REGRESSION analysis , *COOLING loads (Mechanical engineering) , *MACHINE learning , *METAHEURISTIC algorithms , *HEATING load - Abstract
One of the most significant axes of regional, national, and worldwide energy policy is energy efficiency in building design. In particular, the energy efficiency of HVAC systems is of paramount importance. They provide energy for both residential and commercial sectors. As a result, assessing building energy usage is a critical step in optimizing building energy consumption. The impact of eight input factors on the two output variables, heating and cooling loads, for residential structures was explored in this study. For this purpose, the SVR-supervised machine learning algorithm was used. Despite its advantages, such as predictive accuracy and robustness, this method suffers from the fact that there is no specific rule for fitting its parameters. Therefore, six meta-heuristic optimization algorithms were investigated, and the strongest algorithm for optimal parameter fitting for the SVR model was presented. The correlation and error parameters analysis showed that the hybrid model SVR-AEO has the best performance in simulating residential buildings' heating and cooling loads. According to the obtained results, the value of R2 for the cooling and heating loads prediction in the training data is obtained to be 0.9975 and 0.99955, respectively. [Display omitted] • A hybrid Support Vector Regression model is presented to forecast building energy consumption. • The parameter selection for the SVR models is done by six different metaheuristic algorithms. • SVR-AEO simulates the heating and cooling loads of residential structures more accurately than others. • In 240 iterations, the SVR-AEO has the best MSE values in heating and cooling load. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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26. Hydrothermal synthesis of carbon spheres – BiOI/BiOIO3 heterojunctions for photocatalytic removal of gaseous Hg0 under visible light.
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Wu, Jiang, Chen, Xiantuo, Li, Chaoen, Qi, Yongfeng, Qi, Xuemei, Ren, Jianxing, Yuan, Binxia, Ni, Bu, Zhou, Ruixing, Zhang, Jing, and Huang, Tianfang
- Subjects
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HYDROTHERMAL synthesis , *BISMUTH oxides , *HETEROJUNCTIONS , *PHOTOCATALYSIS , *IODATES , *CARBON - Abstract
The carbon modified BiOI/BiOIO 3 (CSs-BiOI/BiOIO 3 ) composites with heterostructures have been prepared via a facile hydrothermal method, using carbon spheres, bismuth nitrate and potassium iodate as precursors. Moreover, a new synthesis mechanism has been proposed. The photocatalytic activities of as-prepared catalysts are evaluated by oxidation of gaseous elemental mercury under visible light irradiation. It is found that the CSs-BiOI/BiOIO 3 exhibits highly enhanced visible photocatalytic activity, compared with that of pure BiOIO 3 . The results show that the Hg 0 removal efficiency of CSs-BiOI/BiOIO 3 reach up to 92.9% and 83.0% under LED light irradiation and simulated sunlight irradiation respectively. The improved photocatalytic activity can be ascribed to the increased the absorption of visible light, enhanced charge separation and transfer and the surface properties. This work points to CSs-BiOI/BiOIO 3 nanocomposites as new and efficient visible light photocatalysts for environmental remediation applications. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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27. Unlocking emerging impacts of carbon tax on integrated energy systems through supply and demand co-optimization.
- Author
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Wang, Meng, Yu, Hang, Yang, Yikun, Lin, Xiaoyu, Guo, Haijin, Li, Chaoen, Zhou, Yue, and Jing, Rui
- Subjects
- *
CARBON taxes , *SUPPLY & demand , *ENERGY tax , *STOCHASTIC programming , *ENERGY consumption , *COAL supply & demand , *CARBON pricing - Abstract
• Build a co-optimization model to optimize supply and demand sides of IES. • Modify stochastic programming to capture both demand and supply sides' scenarios. • Co-optimization model achieves more cost-efficient design considering carbon tax. • Basic and Standard demand-side upgrading are cost-efficient while Premium is not. • Carbon tax accelerates both renewable penetration and demand-side upgrading. Integrated energy systems (IES) can help achieve greater energy efficiency, and then ultimately promote a climate-neutral economy by utilizing local renewable resources. Demand-side energy-saving measures can reduce operational costs associated with energy usage. Most existing IES models, however, focus on supply-side optimization, while the demand-side energy-saving potential and its impacts on whole-system performance are still not clear. The increasing carbon tax makes it even more important to understand the interactions between supply and demand sides to achieve a sustainable system with a minimal carbon charge. Hence, this study proposes a co-optimization model to simultaneously optimize the supply and demand sides of an IES considering the impact of the carbon tax. A selection tree is developed to describe various demand-side envelope upgrading technologies, and a binary tree is established by generating a set of supply-side scenarios with corresponding probabilities. Based on these results, an improved two-stage stochastic programming model is proposed. The robustness of the modeling results was further validated by a simulation–optimization-based uncertainty analysis addressing price uncertainties. A case study in Shanghai indicates that the proposed co-optimization model achieves more cost-efficient solutions than supply-side-only optimization considering carbon tax. Introducing carbon tax can reduce the installed capacity of fuel-based energy technologies by up to 24% and greatly accelerate the penetration of renewables. The increasing carbon tax also promotes the adoption of more advanced energy-saving technologies. Uncertainty analysis reveals acceptable robustness of the optimal demand-side scheme and supply-side configuration with a deviation of less than 5% and a coefficient of variation of 7%. Overall, the observations of the proposed model and case study provide valuable insights for IES design considering an emerging charge of carbon tax. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
28. Comparing stochastic programming with posteriori approach for multi-objective optimization of distributed energy systems under uncertainty.
- Author
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Wang, Meng, Yu, Hang, Lin, Xiaoyu, Jing, Rui, He, Fangjun, and Li, Chaoen
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- *
STOCHASTIC programming , *MONTE Carlo method , *STOCHASTIC models - Abstract
Uncertainty complicates the optimization model of distributed energy systems, it is a challenge to address the fragility of optimal solutions, which calls for an effective but convenient approach to introduce uncertainties into multi-objective optimization. This study proposes and compares the priori and the posteriori modeling approaches for optimizing the design of distributed energy systems under uncertainty. The posteriori approach is developed as a Monte Carlo simulation combined with the deterministic programming model, while the priori approach is formulated as a two-stage stochastic programming model. Both approaches consider economic and environmental objectives and use the same set of uncertainty parameters based on a case study in Shanghai. The results show that, compared with the priori-approach model, the posteriori-approach model leads to an underestimation of the total annual cost, but their total annual carbon emission approximates. Besides, the Pareto frontier cliques from the posteriori approach demonstrate the distributions of system performance, whereas the priori approach can capture the uncertainties at the substantially higher computational cost. Finally, the tradeoff between model complexity and computational cost is discussed to generate more insights on the optimal design, i.e., configuration and dispatch, of distributed energy systems. • Develop a multi-objective stochastic optimization model for distributed energy system • Quantify multiple uncertainties throughout the optimum stochastic scenarios • Combine Monte Carlo simulation and multi-objective deterministic optimization • Propose Pareto frontier cliques to exhibit the optimal solution regions • Comparatively analyze the priori and posteriori uncertainty-modeling approaches [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
29. Combined multi-objective optimization and robustness analysis framework for building integrated energy system under uncertainty.
- Author
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Wang, Meng, Yu, Hang, Jing, Rui, Liu, He, Chen, Pengda, and Li, Chaoen
- Subjects
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MONTE Carlo method , *BUILDING-integrated photovoltaic systems , *PARETO distribution , *STOCHASTIC programming , *RENEWABLE energy sources , *NONLINEAR programming - Abstract
• Propose a multi-objective optimization and robustness analysis integrated framework. • Merge multi-objective optimization with two-stage stochastic programming. • Generate probabilistic stochastic scenarios capturing multiple uncertainties. • Identify the final optimum solutions by two decision-making methods. • Combine optimization with Monte Carlo simulation for robustness analysis. The optimal design of building integrated energy system is sensitive to the variation of uncertain parameters. For addressing the tradeoff of uncertainty and optimality-robustness, this study proposes a combined multi-objective optimization and robustness analysis framework for optimal design of building integrated energy system. The proposed framework includes two parts. In the optimization part, on the basis of scenario generation for capturing the uncertainties of renewable energy sources and energy demands, two-stage multi-objective stochastic mixed-integer nonlinear programming is conducted to optimize the system's economic and environmental objectives. Two decision-making methods are introduced to identify the final optimum solution from the obtained Pareto frontier. In the robustness-analysis part, a combined Monte Carlo simulation and optimization method is implemented to verify the robustness of the optimal solutions. The two parts of the framework are integrated to investigate the case of a hotel in Beijing, China. The results indicate that compared with the stochastic model, the deterministic model underestimates the annual total cost. Achieving economic and environmental optimum is conflicting and needs a trade-off through decision making. Moreover, in the robustness analysis, an acceptable robustness value is identified, considering both the selected objectives and the operation constraints' probability of failure. The Shannon-entropy-based final optimum solution exhibits the best comprehensive performance, with an annual total cost of $695 × 103/year, an annual carbon emissions of 2100 tons/year, and an 8.81% probability of failure. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
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