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Tradeoff between heating energy demand in winter and indoor overheating risk in summer constrained by building standards

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Building Simulation 2021年第4期14卷 987-1003页

作者： Ran Wang shilei lu Wei Feng Bowen Xu School of Environment Science and Engineering Tianjin University92 Weijin RoadTianjin300072China Tianjin Key Laboratory of Built Environment and Energy Application Tianjin UniversityTianjin300350China Lawrence Berkeley National Laboratory BerkeleyCA94720USA

Evidence indicates that improvement of thermal performance of building envelope has the potential for aggravating the indoor overheating risk in summer. On the other hand, evolving building standards continue to strengthen the requirements for thermal performance to achieve the energy-saving target. Therefore, this study quantifies the interaction effect between building standards-oriented building design, heating energy demand in winter, and indoor overheating risk in summer. Building databases with different energy efficiency levels are generated using a randomly generated method. Uncertain variables include not only 13 design parameters but also the running state of natural ventilation and external shading. The indoor overheating risk is assessed in terms of severity and duration. Finally, a multi-objective optimization model integrating metamodels and the non-dominated sorting genetic algorithm is proposed to balance heating energy demand in winter and indoor overheating risk in summer. Results indicate that building standards tend to aggravate overheating risk in summer: the duration and severity of high-performance buildings increased by 40.6% and 24.2% than that of conventional-performance buildings. However, window ventilation could offset the adverse effect, and mitigation of duration and severity can be up to 85.2% and 62.1% for high-performance buildings. Window ventilation can weaken the conflict between heating energy demand in winter and overheating risk in summer. As heating energy demand increased from 6.1 to 67.3 kWh/m^(2), the overheating risk changes little that the duration of overheating risk decreased from 17.5% to 15.6% and severity decreased from 8.7 ℃ to 8.3 ℃.

关键词： climate change indoor overheating risk energy codes building design natural ventilation

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The energy performance and passive survivability of high thermal insulation buildings in future climate scenarios

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Building Simulation 2022年第7期15卷 1209-1225页

作者： Ran Wang shilei lu Xue Zhai Wei Feng School of Environment Science and Engineering Tianjin University92 Weijin RoadTianjin300072China Tianjin Key Laboratory of Built Environment and Energy Application Tianjin UniversityTianjin300350China Lawrence Berkeley National Laboratory BerkeleyCA 94720USA

Given that the passive performance simulation of buildings based on typical meteorological year data and specific design schemes makes it challenging to respond to climate change and refine design requirements on time,this article established a passive performance prediction model for future buildings considering multi-dimensional variables including climate change,building design,and operational *** high thermal insulation buildings under future climates,the mild climate zone is more sensitive than the others,cooling energy demand is more sensitive than heating demand,apartments are more sensitive than office buildings,and passive survivability is more sensitive than energy performance;for buildings of the same type located in the same climate zone,thermal design solutions determine the increase rate of cooling *** potential benefits of climate warming on heating demand reduction are almost zero,but the cooling demand increases significantly,with apartments and office buildings increasing up to 22.1% and 5.0%,*** generally overheat in the future,and the increase rate of the mild zone far exceeds other zones with duration and severity being 3004.8% and 877.7%for apartments,and 884.3% and 288.9%for office buildings,respectively.

关键词： climate change overheating risk cooling demand heating demand scenarios thermal insulation

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Optimization model analysis of centralized groundwater source heat pump system in heating season

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Frontiers in Energy 2015年第3期9卷 343-361页

作者： shilei lu Yunfang QI Zhe CAI Yiran LI School of Environmental Science and Engineering Tianjin University Tianjin 300072 China

The ground-water heat-pump system （GWHP） provides a high efficient way for heating and cooling while consuming a little electrical energy. Due to the lack of scientific guidance for operating control strategy, the coefficient of performance （COP） of the system and units are still very low. In this paper, the running strategy of GWHP was studied. First, the groundwater thermal transfer calculation under slow heat transfixion and transient heat transfixion was established by calculating the heat transfer simulation software Flow Heat and using correction factor. Next, heating parameters were calculated based on the building heat load and the terminal equipment characteristic equation. Then, the energy consumption calculation model for units and pumps were established, based on which the optimization method and constraints were established. Finally, a field test on a GWHP system in Beijing was conducted and the model was applied. The new system operation optimization idea for taking every part of the GWHP into account that put forward in this paper has an important guiding significance to the actual operation of underground water source heat pump.

关键词： optimization model groundwater source heatpump system theoretical analysis example verification,heating season

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Evaluation of the performance of a centralized ground-water heat pump system in cold climate region

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Frontiers in Energy 2014年第3期8卷 394-402页

作者： shilei lu Zhe CAI Yiran LI Li ZHANG School of Environmental Science and Engineering Tianjin University Tianjin 300072 China China Aerospace Construction Group Co. Ltd. Beijing 100071 China

The aim of this study is to performance of a centralized open-loop evaluate the ground-water heat pump （GWHP） system for climate conditioning in Beijing with a cold climate in China. Thus, a long-time test was conducted on a running GWHP system for the heating season from December 2011 to March 2012. The analysis of the testing data indicates that the average heat-pump coefficient of performance （COP） and the COP of the system （COPs） are 4.27 and 2.59. The low value and large fluctuation in the range of COP are found to be caused by the heat transfixion in the aquifer and the bypass in the circulation loop. Therefore, some suggestions are proposed to improve the performance for GWHPs in the cold climate region in China.

关键词： ground-water heat pump (GWHP) actualcoefficient of performance heat transfixion

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Evaluation of High Step-up Power Conversion Systems for Large-capacity Photovoltaic Generation Integrated into Medium Voltage DC Grids

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Chinese Journal of Electrical Engineering 2021年第4期7卷 3-14页

作者： shilei lu Kai Sun Haixu Shi Yunwei Li Guoen Cao Department of Electrical Engineering Tsinghua UniversityBeijing 100084China Department of Electrical and Computer Engineering University of AlbertaEdmonton AB T6G2R3Canada Institute of Electrical Engineering Chinese Academy of SciencesBeijing 100190China

With the increase of dc based renewable energy generation and dc loads,the medium voltage dc(MVDC)distribution network is becoming a promising option for more efficient system *** particular,large-capacity photovoltaic(PV)-based power generation is growing rapidly,and a corresponding power conversion system is critical to integrate these large PV systems into MVDC power *** from traditional ac grid-connected converters,the converter system for dc grid interfaced PV system requires large-capacity dc conversion over a wide range of ultra-high voltage step-up *** is an important issue,yet received limited research so *** this paper,a thorough study of dc-dc conversion system for a medium-voltage dc grid-connected PV system is *** required structural features for such a conversion system are first *** on these features,the conversion system is classified into four categories by series-parallel connection scheme of power *** two existing conversion system configurations as well as a proposed solution are compared in terms of input/output performance,conversion efficiency,modulation method,control complexity,power density,reliability,and hardware ***-depth analysis is carried out to select the most suitable conversion systems in various application scenarios.

关键词： Photovoltaic generation dc-dc conversion medium voltage dc grid large-capacity ultra-high voltage transfer ratio

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A Modular DC/DC Photovoltic Generation System for HVDC Grid Connection

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Chinese Journal of Electrical Engineering 2018年第2期4卷 56-64页

作者： Guoen Cao Kai Sun Siyue Jiang shilei lu Yibo Wang Institute of Electrical Engineering Chinese Academy of SciencesBeijing 100190China State Key Laboratory of Power Systems Tsinghua UniversityBeijing 100084China

A modular DC/DC conversion system with distributed MPPT and centralized step-up converter for photovoltaic energy integrated into HVDC grids is proposed in this *** conversion system consists of two power stages,with MPPT converter as the first stage and a step-up converter as the second *** stages are modular *** the distributed MPPT stage,interleaved boost topology is utilized to effectively reduce the input and output ripples without adding extra *** the centralized step-up stage,narrow-switching-frequency-variation LLC topology is employed,with the modules being configured as input-parallel-output-series ***-range soft-switching property is achieved in the LLC stage to minimize switching *** analysis is carried out for the system voltage gain and design *** and experimental results of a 3kW prototype system are presented to verify the theoretical analysis of the proposed system.

关键词： Photovoltaic generation DC-DC converter HVDC grid connection cascaded configuration

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Application of Horizontal Well Seismic Geo-Steering Technology in XX Block Development

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Open Journal of Yangtze Oil and Gas 2024年第3期9卷 65-74页

作者： Xuecheng Jia Xiaoyi Cheng Hui Ma shilei lu Xin Yang Shuo Wang Xiang Li BGP Geological Research Center Inc. CNPC Zhuozhou China No.6 Oil Production Company Petro China Changqing Oilfield Company CNPC Xian China Pipe China Group Beijing Pipe Co. Ltd. Beijing China

During the development phase horizontal wells are very efficient way to improve the production in the deep coal bed methane. The 8# coal seam in the XX block on the eastern edge of the Ordos Basin has challenges such as deep burial depth (>2000 m), thin coal sweet spot (3 m), and significant short-distance structural fluctuations. The challenges caused a high risk of missing targets and running out of the target layers, as well as difficulties in cementing and completion due to uneven well trajectories. To address these challenges, this paper focuses on solving the issues through detailed precise geological modeling, optimized trajectory design, and accurate seismic geology Steerable Drilling. 1) Based on reasonable velocity field construction and Time-Depth transformation, a precise directional model is constructed using the layer-by-layer approximation principle with reference to marker layers, improving the accuracy of the target spot and avoiding premature or delayed entry into the target;2) Based on a precise geological model, the dip angle of the strata ahead and the development of sweet spots are clearly defined, enabling optimized trajectory design for horizontal wells;3) Using “1 + N” dynamic modeling to update the geological model in real-time during the drilling process, and actively guide the drill bit through the horizontal segment smoothly by using multi-information judgment of the drill bit position. The actual drilling of 80 completed horizontal wells in this area show: That this approach effectively ensures the smooth trajectory and high-quality drilling rate of the horizontal well in the coal seam, providing a basis for subsequent hydraulic fracturing and increasing single-well production. At the same time, it has certain potential value and significance for similar coalbed methane developments under similar geological conditions.

关键词： Seismic Geo-Steerable Horizontal Wells Coalbed Methane Marker Layers

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《绿色建筑评价标准》(2019版)修订概述和水专业要点

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给水排水 2020年第1期46卷 81-86页

作者：吕石磊曾捷中国建筑科学研究院有限公司

为了应对近年来绿色建筑发展的新形势、新挑战和新要求,中国于2019年颁布了修订后的新版《绿色建筑评价标准》。相较上一版标准,新版《绿色建筑评价标准》在评价指标体系、评价方法等方面都做出了重大调整。新版标准中与水专业相关的评... 详细信息

为了应对近年来绿色建筑发展的新形势、新挑战和新要求,中国于2019年颁布了修订后的新版《绿色建筑评价标准》。相较上一版标准,新版《绿色建筑评价标准》在评价指标体系、评价方法等方面都做出了重大调整。新版标准中与水专业相关的评价内容,在整合优化环境保护与资源节约要求的基础上,新增健康舒适与生活便利两类指标,进一步拓展了绿色建筑内涵。主要通过新旧两版《绿色建筑评价标准》的对比,对评价指标体系和水专业的修订要点进行分析和介绍。

关键词：绿色建筑评价标准健康用水智慧运行物业管理节水与水资源利用场地生态与景观

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面向光伏直流升压系统的高压大功率LLC谐振变换器设计方法

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中国电机工程学报 2023年第15期43卷 5970-5982页

作者：卢世蕾孙凯曹国恩易哲嫄李永东电力系统及大型发电设备安全控制和仿真国家重点实验室(清华大学) 北京市海淀区100084 中国科学院电工研究所北京市海淀区100190

文中提出一种适用于光伏直流升压变换系统的高压大功率LLC谐振变换器设计方法与死区时间设计优化方法。文中先介绍大功率LLC变换器的应用场景,光伏直流升压变换器的系统架构和模块拓扑,然后基于模态分析法建立LLC变换器的时域模型,研究... 详细信息

文中提出一种适用于光伏直流升压变换系统的高压大功率LLC谐振变换器设计方法与死区时间设计优化方法。文中先介绍大功率LLC变换器的应用场景,光伏直流升压变换器的系统架构和模块拓扑,然后基于模态分析法建立LLC变换器的时域模型,研究其求解方法。分析大功率LLC变换器与小功率设计时的差异,不能沿用小功率变换器设计方法,为此,从原始参数出发,以高效率为目标,时域模型求解方法为基础,提出一种精确简便的大功率LLC变换器设计方法,另外基于模态分析提出了死区时间设计优化方法。理论研究与提出的方法在一台80kW/5kV光伏直流升压变换器样机上得到验证。

关键词：光伏直流升压系统大功率LLC变换器设计方法软开关死区时间设计

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我国非公有制林业发展的制约因素及对策建议

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北京林业管理干部学院学报 2004年第2期3卷 25-28,32页

作者：陆诗雷国家林业局计资司北京100714

改革开放以来,我国非公有制经济得到了很大发展,但是非公有制林业的发展严重滞后,新时期我国林业跨越式发展迫切需要非公有制林业强有力的支持。发展非公有制林业不仅有利于实施可持续发展战略、促进农村山区发展和扶贫、解决林业建设... 详细信息

改革开放以来,我国非公有制经济得到了很大发展,但是非公有制林业的发展严重滞后,新时期我国林业跨越式发展迫切需要非公有制林业强有力的支持。发展非公有制林业不仅有利于实施可持续发展战略、促进农村山区发展和扶贫、解决林业建设资金不足等问题,而且是有效推进速生丰产林工程、建设发达林业的动力所在。然而,当前我国非公有制林业发展还存在着思想认识、法律保障、林地市场化和政策支持等若干制约因素,因此,只有提高对非公有制林业的思想认识、健全林业法制建设、完善林地流转机制、加大政策扶持力度,才能真正实现非公有制林业的大发展,为我国林业建设和可持续发展服务。

关键词：非公有制林业政府扶持可持续发展对策建议

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