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Optimizing environmental insulation thickness of buildings with CHP-based district heating system based on amount of energy and energy grade

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Frontiers in Energy 2022年第4期16卷 613-628页

作者： Yumei ZHANG Pengfei JIE Chunhua LIU Jing LI School of Mechanical Engineering Beijing Institute of Petrochemical TechnologyBeijing 102617China Engineering and Technology R&D Center of Clean Air Conditioning in Colleges of Shandong Shandong Huayu University of TechnologyDezhou 253000China China Environmental Resources Technology Co. LtdBeijing 100012China

The increase of insulation thickness(IT)results in the decrease of the heat demand and heat medium temperature.A mathematical model on the optimum environmental insulation thickness(OEIT)for minimizing the annual total environmental impact was established based on the amount of energy and energy grade ***,a case study was conducted based on a residential community with a combined heat and power(CHP)-based district heating system(dHS)in Tianjin,***,the effect of IT on heat demand,heat medium temperature,exhaust heat,extracted heat,coal consumption,carbon dioxide(CO_(2))emissions and sulfur dioxide(SO_(2))emissions as well as the effect of three types of insulation materials(i.e.,expanded polystyrene,rock wool and glass wool)on the OEIT and minimum annual total environmental impact were *** results reveal that the optimization model can be used to determine the *** the OEIT of expanded polystyrene,rock wool and glass wool is used,the annual total environmental impact can be reduced by 84.563%,83.211%,and 86.104%,*** can be found that glass wool is more beneficial to the environment compared with expanded polystyrene and rock wool.

关键词： optimum environmental insulation thickness heat medium temperature energy grade extracted heat exhaust heat

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Modeling and design of Active Filter for EMI Cancellation in High Voltage Power Supply of Motor Controller for Electric Vehicle 2

Modeling and Design of Active Filter for EMI Cancellation in...

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2nd China Power Supply Society Electromagnetic Compatibility Conference, CPEMC 2024

作者： Yan, Jianghaoyu Zhai, Li Wang, Shuliang Lv, Mengyuan Ou, Jianchang Liu, Ange National Engineering Research Center of Electric Vehicles Beijing Institute of Technology Beijing China Huawei Technologies Shanghai R&D Center Huawei Technologies Co. Ltd. Shanghai China

ISBN: (纸本)9798331509552

—The rapid switching of IGBT and other power semiconductor devices in the drive motor controller of electric vehicles generates transient voltage and transient current, resulting in conducted and radiated emissions of high-voltage lines exceeding the limits specified in the CISPr 25-2021 standard. In order to solve the problems of poor electro -magnetic interference suppression and large volume in the low-frequency range of passive EMI filters (PEF), as well as poor high-frequency interference suppression in active filters, an active EMI filter (AEF) suitable for high-voltage power supply of electric vehicle motor controllers was designed. A high-frequency circuit model of the proposed high-precision AEF was established, and a prototype of the AEF was designed. The insertion loss of AEF is greater than 35.2dB from 100kHz to 100MHz, with a maximum of 39.3dB. Compared with PEF with the same insertion loss, the proposed HEF reduces its volume by approximately 50%. When the motor operates under load, the conduction voltage of the motor controller meets the requirements of level 3 of CISPr25-2021. ©2024 IEEE.

关键词： Insulated gate bipolar transistors (IGBT)

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Efficiency-loss analysis of monolithic perovskite/silicon tandem solar cells by identifying the patterns of a dual two-diode model’s current-voltage curves

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Journal of Semiconductors 2023年第8期44卷 68-77页

作者： Yuheng Zeng Zetao ding Zunke Liu Wei Liu Mingdun Liao Xi Yang Zhiqin Ying Jingsong Sun Jiang Sheng Baojie Yan Haiyan He Chunhui Shou Zhenhai Yang Jichun Ye Ningbo Institute of Materials Technology and Engineering Chinese Academy of SciencesNingbo 315201China University of Chinese Academy of Sciences Beijing 100049China Zhejiang Engineering Research Center for Energy Optoelectronic Materials and Devices Ningbo Institute of Materials Technology&EngineeringCASNingbo 315201China Zhejiang Energy Group R&D Hangzhou 310003China

In this work,we developed a simple and direct circuit model with a dual two-diode model that can be solved by a SPICE numerical simulation to comprehensively describe the monolithic perovskite/crystalline silicon(PVS/c-Si)tandem solar *** are able to reveal the effects of different efficiency-loss mechanisms based on the illuminated current density-voltage(J-V),semi-log dark J-V,and local ideality factor(m-V)*** effects of the individual efficiency-loss mechanism on the tandem cell’s efficiency are discussed,including the exp(V/VT)and exp(V/2VT)recombination,the whole cell’s and subcell’s shunts,and the Ohmic-contact or Schottky-contact of the intermediate *** can also fit a practical J-V curve and find a specific group of parameters by the trial-and-error *** the fitted parameters are not a unique solution,they are valuable clues for identifying the efficiency loss with the aid of the cell’s structure and experimental *** method can also serve as an open platform for analyzing other tandem solar cells by substituting the corresponding circuit *** summary,we developed a simple and effective methodology to diagnose the efficiency-loss source of a monolithic PVS/c-Si tandem cell,which is helpful to researchers who wish to adopt the proper approaches to improve their solar cells.

关键词： monolithic perovskite/silicon tandem solar cell efficiency-loss analysis dual two-diode model SPICE numerical simula-tion

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Thermal control of thin films with nano structure 9

Thermal control of thin films with nano structure

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9th European Thermal Sciences Conference, EUrOTHErM 2024

作者： Sato, M. Takahara, Y. Matsumoto, M. Kajinami, N. Hanaoka, M. Iwakawa, M. Department of Mechanical Engineering and Science Graduate School of Engineering Kyoto University Kyoto615-8540 Japan Advanced Technology R&D Center Mitsubishi Electric Corporation Hyogo661-8661 Japan

Thermoelectric energy conversions have been attracting much attention, which directly generate electric energy from thermal one by utilizing the Seebeck effect. Among various efforts to improve the conversion efficiency, control of phonon propagation with nano-scale structures has been popular, which utilize phonon scatterings on structural interfaces. The concept is based on the difference of mean free path (MFP) between phonons and electrons (charge carriers). In typical cases with silicon-base devices, MFP of phonons is in an order of 100 nm while that of electrons is 1-10 nm. Thus structures of 10-100 nm size are expected to be effective for suppressing the phonon heat transfer without much reducing the electric transport, leading to conversion efficiency improvement. We have developed a numerical scheme to investigate phonon transport based on the Boltzmann transport equation (BTE) for time development of the phonon distribution function. To treat various shapes of nano-scale structures, we have newly introduced a VOF (volume of fluid) like scheme. In the presentation, we will show results of several test systems of nano-structured Si thin films, with evaluation of effective electric conductivity, to discuss how much nano-scale structures improve the conversion efficiency. © Published under licence by IOP Publishing Ltd.

关键词： Conversion efficiency

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Improved Topology Optimization Model for Heat Sink design Under Natural Convection 1

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29th International Conference on Computational and Experimental engineering and Sciences, ICCES 2023

作者： Zhang, Shanshan Huang, Yicang School of Civil Engineering and Architecture Wuhan University of Technology Wuhan430070 China R&D Center Wuhan Second Ship Design and Research Institute Wuhan430205 China

ISBN: (数字)9783031449475

ISBN: (纸本)9783031449468

This paper proposes an improved topology optimization model based on SIMP method for heat sink design under natural convection conditions. It uses a double-projection method to reduce the performance deviation caused by conventional filtering and projection methods in the topology optimization procedure. And a shape optimization procedure is adopted as a post-processing method to further enhance the thermal performance of the extracted topology-optimized heat sink by optimizing its boundary profiles. A practical 3d heat sink for cooling the PTC heat source is designed using the improved topology optimization model and manufactured by the laser-based powder bed fusion (L-PBF) 3d printing. The heat dissipation performance of the novel-designed heat sink is experimentally and numerically examined and it achieves a 23.5% lower thermal resistance compared to the conventional plate-fin heat sink. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2024.

关键词： Shape optimization

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A distributive Hybrid Cell Balancing Technique for Series-Connected Lithium-Ion Cells 3

A Distributive Hybrid Cell Balancing Technique for Series-Co...

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3rd International Conference on Emerging Trends in Electrical, Control, and Telecommunication engineering, ETECTE 2024

作者： Imran, Syed Ali Kazmi, Syed Najeeb Ali Sakandar, Huzaifa Ulasyar, Abasin Khalid, Alishba Electrical Engineering Department University of Engineering & Technology Taxila Pakistan School of Engineering & Built Environment Griffith University Gold Coast Australia Drivr Team Washing Machine-R&D Center Beko Istanbul Turkey

ISBN: (纸本)9798331504861

As the demand for high energy density batteries has surged due to their use in transportation electrification and energy storage systems (ESS), the role of battery management systems (BMS) has become even more critical. Individual cells in a battery pack can develop imbalances in their state of charge (SOC) during charge/discharge operations, which in turn can diminish battery pack’s ability to operate at its rated capacity. Therefore, cell balancing that ensures optimal performance of a battery pack becomes a critical function of the BMS. In this study, a distributive hybrid cell balancing technique is presented which incorporates both passive and active balancing strategies for optimal cell balancing based on the difference in SOC among the cells. The proposed method is designed to address imbalance in SOC more effectively and in a shorter duration compared to conventional inductor based active balancing and resistors based passive balancing. Simulations were run to validate the performance of the proposed technique during three different modes of battery operation: idle, charging, and discharging. Furthermore, a hardware prototype was also developed for practical demonstration of the proposed hybrid technique. ©2024 IEEE.

关键词： Battery Pack

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A driver Fatigue Modeling Method Based on Enhanced EEG-EOG Fusion Network for Human-Machine Co-driving 4

A Driver Fatigue Modeling Method Based on Enhanced EEG-EOG F...

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4th International Signal Processing, Communications and engineering Management Conference, ISPCEM 2024

作者： Wang, Yinan Zhao, Yang Gong, Lizhou Yu, Yewei Liu, Hanxu School of Automation Engineering University of Electronic Science and Technology of China Chengdu611731 China Global R&D Center China FAW Corporation Limited Changchun130013 China

ISBN: (纸本)9798331528676

driver fatigue detection serves as an essential tool in the process of human-machine co-driving, capable of promptly alerting intelligent systems to assume control of the vehicle. The detection of driver fatigue based on EEG signals currently stands as a primary method for assessing the mental state of individuals. However, at the same time, there are still some problems with EEG signals, such as being prone to noise interference and low cross-subject recognition rate. In addressing the aforementioned issues, this study introduces a method for modeling driver fatigue through the fusion of features extracted from EEG and EOG signals. The proposed model incorporates high-precision EEG equipment and good cross-subject EOG equipment as input. Comprising EEGNet, SANet (Spatial Attention Network), SCONV (and Separable Convolutional Network), the model employs a multi-modal approach to assess driver performance and quantify fatigue. The model effectiveness was verified on the SEEd-VIG data set. The test results show that the recognition accuracy of this method reaches 91%, which is better than the currently popular model. At the same time, the cross-subject recognition accuracy test was conducted, and the average accuracy reached 87%, which proved the generalization performance of the model across subjects and verified the effectiveness of the model. ©2024 IEEE.

关键词： Fluorescent screens

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FAILUrE ANALYSIS FOr LOCK SENSING LIMIT SWITCH ON EMU dOOr SYSTEM

FAILURE ANALYSIS FOR LOCK SENSING LIMIT SWITCH ON EMU DOOR S...

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ASME 2024 International Mechanical engineering Congress and Exposition, IMECE 2024

作者： Wu, Lvxian Hong, Haifeng Zhang, Xiaoming Zhang, Long Lu, Hang Li, dong Yin, Yanbo Tang, Yuxuan Huang, Wei Chen, Qiubo The R&D Department CRRCMA QuincyMA02171 United States National Passenger Rail Vehicle Engineering and Technology Center CRRC-Changchun Jilin Changchun130062 China

ISBN: (纸本)9780791888681

The EMU plug sliding door system's security loop relies on two crucial components: the lock limit switch and the lock sensing limit switch, wired in series. Any malfunction in either switch during operation can disrupt the train's ability to initiate traction during berthing or induce emergency brake during revenue service, leading to operational issues, and impacting the service schedule and service life of the vehicle. Thus, ensuring the high-quality manufacture and precise installation of these limit switches is paramount. This paper focuses on the analysis of serval fault reports of the security loop. Upon inspection of current units, sporadic lock sensing limit switch malfunctions emerge as the primary cause of safety loop failures. Consequently, this paper aims to conduct an in-depth analysis of lock sensing limit switch failures on different train series, focusing on identifying the underlying issues and proposing practical solutions. Investigations and testing were conducted on actuation force, fitness of the components, and electrochemical oxidation to identify the root cause of the safety loop’s failure. A manufacturing defect was located and corrected significantly reducing the failure rate. Further correction, experience, and suggestions are provided for manufacturers and car builders. © 2024 by ASME.

关键词： Taxation

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dESIGN, ANALYSIS ANd TEST OF TrUCK FrAME ANd BOLSTEr FOr rAILWAY VEHICLE

DESIGN, ANALYSIS AND TEST OF TRUCK FRAME AND BOLSTER FOR RAI...

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ASME 2024 International Mechanical engineering Congress and Exposition, IMECE 2024

作者： Hong, Haifeng Xue, Shihai Zhang, Wenkang Zhang, Long Yin, Yanbo Wu, Lvxian Lu, Peng Chen, Qiubo National Passenger Rail Vehicle Engineering and Technology Center CRRC-Changchun Jilin Changchun130062 China The R&D Department CRRCMA QuincyMA02171 United States

ISBN: (纸本)9780791888681

In North American railway industry, the truck design generally takes into consideration of several factors, e.g. the axle load, maximum operating and design speed, new and worn wheel diameter, arrangement of journal box, service life, safety, stability, ride quality and maintainability and etc. and the design typically follows applicable FrA, APTA and AAr standards. To ensure the truck frame and bolster have enough strength for loads during testing and revenue services, FEA is used to calculate stresses in the frame and bolster for static and fatigue load cases. Various static loading cases as specified in EN standard were simulated to make sure that these stresses shall not exceed half of the yield stress. The fatigue stress calculation is based on cyclic loads, taking into consideration of forces experienced during vehicle accelerating and braking. Von-Mises stresses are calculated for static load cases. The modified Goodman line is solved for the endurance limit using the yield strength of the material. Finally, static and fatigue testing are performed to compare and validate the simulated results. © 2024 by ASME.

关键词： Fatigue testing

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A Zn-Cluster-Based MOF for Efficient Separation of C3H8/C2H6/CH4

Chem and Bio Engineering

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Chem and Bio engineering 2024年第8期1卷 658-663页

作者： Wang, Yue Lai, Yujie Liu, Jieyu Fan, Ziwen Quan, Xueheng Zhang, Tong Wang, Changhong Xu, Cong Chen, Qi Niu, Zheng College of Chemistry Chemical Engineering and Materials Science Soochow University Jiangsu Suzhou215123 China Hebei Normal University Hebei Shijiazhuang050024 China Technology R&D Center Jinhong Gas Co. Ltd. Jiangsu Suzhou215143 China

The separation and purification of methane from natural gas are crucial chemical processes. Herein, we report a Zn-cluster-based MOF (SdMOF-3), enabling the efficient separation of mixed low-carbon alkanes. The unique Zn clusters in the MOF enhance its interaction with hydrogen atoms in alkanes, thus realizing the separation of saturated light alkanes. Single-component gas adsorption tests revealed that SdMOF-3 exhibits significantly higher affinity for C3H8 compared to CH4 and C2H6 at 298 K. dynamic column penetration experiments with mixed gases demonstrated the excellent separation performance of SdMOF-3 for separating C3H8 and C2H6 from CH4 © 2024 The Authors. Co-published by Zhejiang University and American Chemical Society.

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