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Full-Text Articles in Engineering

Synthesis Of Sea Urchin-Like Nico2o4 Via Charge-Driven Self-Assembly Strategy For High Performance Lithium-Ion Batteries, Bin Wang, Chi-Wing Tsang, Ka Ho Li, Yuanyuan Tang, Yanping Mao, Xiao-Ying Lu Jan 2019

Synthesis Of Sea Urchin-Like Nico2o4 Via Charge-Driven Self-Assembly Strategy For High Performance Lithium-Ion Batteries, Bin Wang, Chi-Wing Tsang, Ka Ho Li, Yuanyuan Tang, Yanping Mao, Xiao-Ying Lu

Technological and Higher Education Institute of Hong Kong (THEi) Staff Publications

In this study, hydrothermal synthesis of sea urchin-like NiCo2O4 was successfully demonstrated by a versatile charge-driven self-assembly strategy using positively charged poly(diallydimethylammonium chloride) (PDDA) molecules. Physical characterizations implied that sea urchin-like microspheres of ~ 2.5 μm in size were formed by self-assembly of numerous nanoneedles with a typical dimension of ~ 100 nm in diameter. Electrochemical performance study confirmed that sea urchin-like NiCo2O4 exhibited high reversible capacity of 663 mAh g−1 after 100 cycles at current density of 100 mA g−1. Rate capability indicated that average capacities of 1085, 1048, 926, 642, 261, and 86 mAh g−1 ...


Study On The Performance Of Distributed Energy Systems Based On Historical Loads Considering Parameter Uncertainties For Decision Making., Chong Zhang, Xue Xue, Qianzhou Du, Yimo Luo, Wenjie Gang Jan 2019

Study On The Performance Of Distributed Energy Systems Based On Historical Loads Considering Parameter Uncertainties For Decision Making., Chong Zhang, Xue Xue, Qianzhou Du, Yimo Luo, Wenjie Gang

Technological and Higher Education Institute of Hong Kong (THEi) Staff Publications

Distributed energy systems (DESs) are becoming increasingly popular because of their high-energy efficiency and low pollution emissions. Accurate performance evaluation of such systems is critical for processes at the early design stages. However, there are considerable uncertainties in terms of the parameters used for performance evaluation and design optimization, including component efficiencies, customer demands, and energy markets. These uncertainties can significantly influence the performance of DESs. Without consideration of these uncertainties, the performance of DESs can be overestimated or underestimated, which leads to inaccurate decision-making. Therefore, this paper presents a comprehensive evaluation of the performance of DESs by considering uncertainties ...


Recycling Licoo2 With Methanesulfonic Acid For Regeneration Of Lithium-Ion Battery Electrode Materials., Bin Wang, Xin-Ye Lin, Yuanyuan Tang, Qiang Wang, Michael K.H. Leung, Xiao-Ying Lu Jan 2019

Recycling Licoo2 With Methanesulfonic Acid For Regeneration Of Lithium-Ion Battery Electrode Materials., Bin Wang, Xin-Ye Lin, Yuanyuan Tang, Qiang Wang, Michael K.H. Leung, Xiao-Ying Lu

Technological and Higher Education Institute of Hong Kong (THEi) Staff Publications

With the massive consumption of lithium-ion batteries in portable consumer electronics and electric vehicles, proper disposal of spent batteries is of paramount importance for sustainable development. In this study, biodegradable organic methanesulfonic acid (MSA) is investigated for the first time to leach valuable metals from waste LiCoO2 powders for battery material regeneration. Under the optimal conditions, leaching efficiencies of lithium and cobalt are achieved at nearly ∼100% and ∼100%, respectively. Comparison experiment indicates that MSA can achieve better leaching performance than previously reported organic acids (e.g. citric acid, malonic acid, succinic acid, oxalic acid) under the same conditions. Besides ...


Improving The Energy Efficiency Of Petrochemical Plant Operations: A Measurement And Verification Case Study Using A Balanced Wave Optimizer, Eve Man Hin Chan, Kar-Kit Chu, Hin-Fung Chow, Chi-Wing Tsang, Danny Chi Kuen Ho, Shuk-Kei Ho Jan 2019

Improving The Energy Efficiency Of Petrochemical Plant Operations: A Measurement And Verification Case Study Using A Balanced Wave Optimizer, Eve Man Hin Chan, Kar-Kit Chu, Hin-Fung Chow, Chi-Wing Tsang, Danny Chi Kuen Ho, Shuk-Kei Ho

Technological and Higher Education Institute of Hong Kong (THEi) Staff Publications

The Chinese petrochemical industry is facing pressure to meet strict targets of energy consumption and carbon emission reductions. Water pumps are the primary equipment used in most chemical and agrochemical industries sectors since water is commonly used for cooling and heating purposes, but these pumps also consume a large amount of energy. Other uses of water pumps in these industries include producing steam for heating, preparing reaction media or absorptive reagents, rinsing products, and distilling. As for the electrical components of the water pump systems, current technologies of variable frequency drives and superconducting transmission lines are unable to increase the ...


Micro/Nanostructured Mnco2o4.5 Anodes With High Reversible Capacity And Excellent Rate Capability For Next Generation Lithium-Ion Batteries, Bin Wang, Shifeng Wang, Yuanyuan Tang, Chi-Wing Tsang, Jinchuan Dai, Michael K.H. Leung, Xiao-Ying Lu Jan 2019

Micro/Nanostructured Mnco2o4.5 Anodes With High Reversible Capacity And Excellent Rate Capability For Next Generation Lithium-Ion Batteries, Bin Wang, Shifeng Wang, Yuanyuan Tang, Chi-Wing Tsang, Jinchuan Dai, Michael K.H. Leung, Xiao-Ying Lu

Technological and Higher Education Institute of Hong Kong (THEi) Staff Publications

Lithium-ion batteries have already achieved great success in consumer electronics. However, the electrochemical characteristics of the existing electrodes have constrained their widespread applications in electric vehicles, which need technical demands of high energy density and fast charging. Thus, it is highly desirable to explore high-performance electrodes with high reversible capacity and excellent rate capability. In this study, micro/nanostructured MnCo2O4.5 anodes were synthesized by hydrothermal treatment with the presence of positively charged poly(diallyldimethylammonium chloride). Physicochemical property studies suggested that the as-prepared MnCo2O4.5 of 2–5 µm in diameter was mainly composed of numerous nanoneedles, which were further ...


Year-Round-Based Optimization Of High-Low Control In The Regenerative Indirect Evaporative Cooler (Riec), Huaxia Yan, Yi Chen, Weilong Zhang Jan 2019

Year-Round-Based Optimization Of High-Low Control In The Regenerative Indirect Evaporative Cooler (Riec), Huaxia Yan, Yi Chen, Weilong Zhang

Technological and Higher Education Institute of Hong Kong (THEi) Staff Publications

The performance of the regenerative indirect evaporative cooler (RIEC) highly depends on ambient temperature and humidity. To maintain indoor thermal comfort, proper control strategy is essential. Previous research indicates that high–low (H-L) control by using multispeed technology is superior to the conventional on–off control in terms of energy consumption and thermal comfort. Under H-L control, a fan switches between a high speed and a low speed. The high speed is determined by the peak load. However, the selection of low speed involves a great sense of subjectivity. Therefore, the influence of low speed on system performance is comprehensively ...


Thermal Properties Study And Performance Investigation Of Potassium Formate Solution In A Falling Film Dehumidifier/Regenerator., Tao Wen, Meng Wang, Yi Chen, Weifeng He, Yimo Luo Jan 2019

Thermal Properties Study And Performance Investigation Of Potassium Formate Solution In A Falling Film Dehumidifier/Regenerator., Tao Wen, Meng Wang, Yi Chen, Weifeng He, Yimo Luo

Technological and Higher Education Institute of Hong Kong (THEi) Staff Publications

Compared with the extensive attention drawn by salt solutions, the promising potassium formate (KCOOH) solution which has smaller causticity and lower price receives little attention in the field of liquid desiccant cooling system (LDCS). Consequently, the present paper studied both the thermal properties and mass transfer performance of KCOOH solution for its practical engineering application. The vapor pressure and density of KCOOH solution under different concentrations and temperatures were measured and then fitted in the form of polynomials with the mean absolute relative deviation (MARD) of 0.06% and 0.551% respectively. Referring to the data in the existing literature ...


A Novel 3d Simulation Model For Investigating Liquid Desiccant Dehumidification Performance Based On Cfd Technology., Tao Wen, Yimo Luo, Lu Lin Jan 2019

A Novel 3d Simulation Model For Investigating Liquid Desiccant Dehumidification Performance Based On Cfd Technology., Tao Wen, Yimo Luo, Lu Lin

Technological and Higher Education Institute of Hong Kong (THEi) Staff Publications

Previous 2D CFD simulation models fail to elaborate the actual simultaneous flow and dehumidification process in liquid desiccant cooling system. Accordingly, the present study successfully developed a novel 3D simulation model for investigating the liquid desiccant dehumidification performance of a falling film dehumidifier. The penetration mass transfer model was implemented in the simulation to account for the interfacial dehumidification process. Experimental system was built for the model validation and the results indicated that the newly developed 3D CFD model could predict the absolute moisture removal accurately with an average deviation of 7%. Parametric study revealed that the dehumidification performance was ...


Flexible Integration Of Liquid Air Energy Storage With Liquefied Natural Gas Regasification For Power Generation Enhancement, Xiaohui She, Tongtong Zhang, Lin Cong, Xiaodong Peng, Chuan Li, Yimo Luo, Yulong Ding Jan 2019

Flexible Integration Of Liquid Air Energy Storage With Liquefied Natural Gas Regasification For Power Generation Enhancement, Xiaohui She, Tongtong Zhang, Lin Cong, Xiaodong Peng, Chuan Li, Yimo Luo, Yulong Ding

Technological and Higher Education Institute of Hong Kong (THEi) Staff Publications

Liquid Air Energy Storage (LAES) is one of the most promising energy storage technologies for achieving low carbon emissions. Our research shows that the LAES produces a considerable amount of excess heat that cannot be cost-effectively utilised in a standalone LAES system. On the other hand, the regasification of liquefied natural gas (LNG) often leads to waste of a large amount of high-grade cold energy. Therefore, this paper proposes the integration of the LAES with the LNG regasification process via a Brayton cycle (denoted as LAES-Brayton-LNG), where pressurized propane is used as both the heat transfer fluid and storage material ...


A Review Of Renewable Energy Assessment Methods In Green Building And Green Neighborhood Rating Systems, Chong Zhang, Chengliao Cui, Ying Zhang, Jiaqi Yuan, Yimo Luo, Wenjie Gang Jan 2019

A Review Of Renewable Energy Assessment Methods In Green Building And Green Neighborhood Rating Systems, Chong Zhang, Chengliao Cui, Ying Zhang, Jiaqi Yuan, Yimo Luo, Wenjie Gang

Technological and Higher Education Institute of Hong Kong (THEi) Staff Publications

Green buildings and neighborhoods can help mitigate impacts of buildings on the environment, society and economy. Many rating systems or tools have been developed worldwide to assess and certificate green buildings or green neighborhoods. Renewable energy plays an important role in achieving green buildings/neighborhoods or zero energy buildings/neighborhoods by reducing fuel consumption and pollution emissions. However, substantial differences exist in assessing or quantifying the renewable energy in green building/neighborhood rating systems. This paper therefore provides a comprehensive review on renewable energy assessment methods adopted in green building/neighborhood rating systems, which would be very helpful to understand ...