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

Shilei LU,Zhe CAI,Li ZHANG,Yiran LI

《能源前沿（英文）》 2014年 第8卷 第3期   页码 394-402 doi: 10.1007/s11708-014-0310-1

摘要： The aim of this study is to evaluate the performance of a centralized open-loop 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)     actual coefficient of performance     heat transfixion    

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Compressor performance of two-stage turbocharging system

HE Yituan, MA Chaochen, WEI Mingshan, ZHU Zhifu, HE Yituan

《机械工程前沿（英文）》 2008年 第3卷 第2期   页码 218-221 doi: 10.1007/s11465-008-0027-0

摘要： To study the performance of high and low stage compressors and that of the system as a whole, a two-stage turbocharging system was matched, and a special two-stage turbocharging system test bench was built. For each test curve, the speeds of the two stage turbochargers were adjusted to the fixed data, and a compressor performance experiment was performed. The results showed many differences between the corrected mass flow and the actual mass flow of the high pressure (HP) stage compressor. To find out the actual supercharging effect of the two-stage turbocharging system, it is better to adopt the actual mass flow. The two-stage turbocharging system in this paper has much higher efficiency under most operating conditions if the pressure ratio assignment is 1:1. The system can get very high supercharging pressure when the speeds of the two stage turbochargers are rather low, which ensures the system’s security and reliability.

关键词： special two-stage     HP     performance experiment     reliability     actual supercharging    

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Performance of rolling piston type rotary compressor using fullerenes (C70) and NiFe

Ruixiang WANG,Yihao ZHANG,Yi LIAO

《能源前沿（英文）》 2020年 第14卷 第3期   页码 644-648 doi: 10.1007/s11708-017-0453-y

摘要： A novel way for a compressor to improve its coefficient of performance was proposed in this paper. Fullerenes (C70) and NiFe O nanocomposites were modified by span 80 and dispersed in refrigeration oil by solid grinding (SG). Besides, the tribological properties of the nanocomposites were investigated using a four ball friction tester. The results show that when the mass concentration of fullerenes nanocomposite is higher than 60 ppm and the concentration of nano-oil is 2 g/L, the friction coefficient decreases from 0.13 to 0.06 which means the wear is reduced. The coefficient of performance of the compressor under the air conditioning test condition can be raised by 1.23%.

关键词： rotary compressor     friction coefficient     nanocomposite materials     coefficient of performance     fullerenes (C70)    

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Nonlinear design-point performance adaptation approaches and their comparisons for gas turbine applications

Y. G. LI, P. PILIDIS,

《能源前沿（英文）》 2009年 第3卷 第4期   页码 446-455 doi: 10.1007/s11708-009-0042-9

摘要： Accurate performance simulation and understanding of gas turbine engines is very useful for gas turbine manufacturers and users alike and such a simulation normally starts from its design point. When some of the engine component parameters for an existing engine are not available, they must be estimated in order that the performance analysis can be started. Therefore, the simulated design point performance of an engine may be slightly different from its actual performance. In this paper, two nonlinear gas turbine design-point performance adaptation approaches have been presented to best estimate the unknown component parameters and match available design point engine performance, one using a nonlinear matrix inverse adaptation method and the other using a Genetic Algorithm-based adaptation approach. The advantages and disadvantages of the two adaptation methods have been compared with each other. In the approaches, the component parameters may be compressor pressure ratios and efficiencies, turbine entry temperature, turbine efficiencies, engine mass flow rate, cooling flows, and by-pass ratio, etc. The engine performance parameters may be thrust and SFC for aero engines, shaft power, and thermal efficiency for industrial engines, gas path pressures, temperatures, etc. To select the most appropriate to-be-adapted component parameters, a sensitivity bar chart is used to analyze the sensitivity of all potential component parameters against the engine performance parameters. The two adaptation approaches have been applied to a model gas turbine engine. The application shows that the sensitivity bar chart is very useful in the selection of the to-be-adapted component parameters, and both adaptation approaches are able to produce good quality engine models at design point. The comparison of the two adaptation methods shows that the nonlinear matrix inverse method is faster and more accurate, while the genetic algorithm-based adaptation method is more robust but slower. Theoretically, both adaptation methods can be extended to other gas turbine engine performance modelling applications.

关键词： gas turbine     engine     performance adaptation     performance matching     design-point performance simulation     influence coefficient matrix     genetic algorithm    

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建设项目协调管理绩效评价

郭峰,刘慧

《中国工程科学》 2011年 第13卷 第8期   页码 97-102

摘要：

文章将功能系数法与广泛应用于管理评价的逻辑框架法进行综合运用，认为项目及组织的可持续发展是建设项目协调管理的最高境界，从目标协调管理绩效、组织协调管理绩效、利益相关方协调管理绩效及项目和组织可持续发展性4个方面建立了建设项目协调管理绩效评价指标体系，并给出各指标的计算方法，运用功能系数法计算建设项目协调管理绩效综合评价功能系数，从而有效量化了对建设项目协调管理绩效的综合评价。最后，通过算例研究，验证了指标体系构建方法及各指标计算方法的可行性，这个方法可以有效地衡量协调管理的功能。

关键词： 建设项目协调管理     绩效评价指标体系     功能系数法    

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Integration of renewable energies, flexible loads and storages into the German power grid: Actual situation

Harald SCHWARZ, Xiaoshu CAI

《能源前沿（英文）》 2017年 第11卷 第2期   页码 107-118 doi: 10.1007/s11708-017-0470-x

摘要： Starting from the late 1990’s, the German government decided to change the national electric power supply system dramatically. The main stimulating instrument was the German Law on Renewable Energies (Erneuerbare Energien Gesetz (EEG)), which guaranteed a fixed feed-in tariff to everyone who was willing to invest into renewable generation. Based on the year of commissioning, defined revenues per kWh were fixed for the next 20 years. Due to a very attractive over-funding, more than 1.5 million renewable generation units were connected to the German grid up to the end of 2015. According to the EEG, renewable generation units can feed to the grid wherever they are located and whenever they are able to produce. The old physical principle was and is still neglected, which clearly stated that generation always has to follow the demand—simply due to the limited availability of storages in the power system. Only in cases, when temporarily renewable overproduction exceeds the tolerable loading of lines or transformers respectively endangers the system stability in total, are German grid operators allowed to announce curtailments by emergency measures. Even in such cases, the “not produced energy” from renewable sources has to be funded. Although the installed capacity from renewables is much higher than the peak load in Germany, it contributes only about 32% to German average annual energy. Unfortunately, the regional distribution of renewable generation and load is very different, e.g. in the northeast of Germany, this Renewable Energy (RE)-ratio meanwhile exceeds 100% due to the high RE-penetration and low load. High transits of renewable overproduction from the north to the south will be necessary at nearly every day per year. Therefore, a tremendous change is needed within the German power grid. This paper will give a first overview followed by several others, describing possible solutions on how to overcome this critical situation.

关键词： grid integration     renewable energies     system stability     storages     flexible loads     new market design    

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Impact of renewable energies on the operation and economic situation of coal fired power stations: Actual

Hans-Joachim KRAUTZ, Alexander LISK, Joachim POSSELT, Christian KATZER

《能源前沿（英文）》 2017年 第11卷 第2期   页码 119-125 doi: 10.1007/s11708-017-0468-4

摘要： Due to the fluctuating character of the renewable energy sources the demand of conventional power plants for flexibility is increasing. In the recent years, in Germany there has been a fast rise of production capacity of renewable energies, especially from wind turbines, photovoltaic installations, and biomass plants. The installed nominal power of wind turbines is actually (December 2016) 42 GW and of photovoltaic installations 40?GW. The renewable electric energy production in Germany is about 190?TWh/a, which represents a share of 33% of the yearly demand. The increased need for flexibility affects both the power gradients as well as the minimum load of conventional power plants. Due to this flexibility behaviour, conventional power plants are faced with problems concerning the durability of power plant components, corrosion, more maintenance effort and consequently the overall life expectancy. Another consequence of the increasing share of renewable energies is the decreasing full load operating hours, especially of coal fired and gas power plants. Along with decreasing revenues from the energy exchange market, coal fired power plants are faced with new economically challenges.

关键词： flexible load operation     minimal load     power gradients     power plant maintenance     corrosion     life expectancy    

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Experimental study on performance of passive and active solar stills in Indian coastal climatic condition

R. LALITHA NARAYANA, V. RAMACHANDRA RAJU

《能源前沿（英文）》 2020年 第14卷 第1期   页码 105-113 doi: 10.1007/s11708-018-0536-4

摘要： This present work is aimed to examine the effect of mass flow rate on distillate output and performance of a solar still in active mode. Outdoor experiments were conducted at the coastal town, Kakinada (16° 93′N/83° 33′E), Andhra Pradesh, India. A solar still with a 30° of fixed cover inclination, 1m of effective basin area, and a flat-plate collector (FPC) with an effective area of 2 m were used. An attempt was also made earlier in passive mode to optimize the water depth for the same solar still for maximum yield and distillation efficiency. For the passive still, it is observed that the capacity of heat storage and heat drop are significant parameters that affect the still performance. For the selected still design, the study reveals that 0.04 m water depth is the optimum value for specific climatic conditions. In the active solar still, with the optimum water depth, different flow rates of 0.5, 1 and 1.5 L/min are considered through FPC. It is observed that both the mass flow rate and the variation of internal heat transfer coefficients with the mass flow rate have a significant effect on the yield and performance of the still. The experimental results show that the combination of 1.5 L/min mass flow rate and an optimum water depth of 0.04m leads to a maximum yield for the active solar still. The enhanced yield of the active solar still is 57.55%, compared with that of the passive solar still, due to increase in area of radiation collection and more heat absorption rate.

关键词： distillation efficiency     solar still     heat transfer coefficient     water depth     optimum and mass flow rate    

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Comprehensive performance analysis and optimization of 1,3-dimethylimidazolylium dimethylphosphate-water

Gorakshnath TAKALKAR, Ahmad K. SLEITI

《能源前沿（英文）》 2022年 第16卷 第3期   页码 521-535 doi: 10.1007/s11708-021-0720-9

摘要： The energy and exergy analyses of the absorption refrigeration system (ARS) using H O-[mmim][DMP] mixture were investigated for a wide range of temperature. The equilibrium Dühring ( - - ) and enthalpy ( - - ) of mixture were assessed using the excess Gibbs free non-random two liquid (NRTL) model for a temperature range of 20°C to 140°C and from 0.1 to 0.9. The performance validation of the ARS cycle showed a better coefficient of performance (COP) of 0.834 for H O-[mmim][DMP] in comparison to NH -H O, H O-LiBr, H O-[emim][DMP], and H O-[emim][BF4]. Further, ARS performances with various operating temperatures of the absorber ( ), condenser ( ), generator ( ), and evaporator ( ) were simulated and optimized for a maximum COP and exergetic COP (ECOP). The effects of from 50°C to 150°C and and from 30°C to 50°C on COP and ECOP, the , , and circulation ratio (CR) of the ARS were evaluated and optimized for from 5°C to 15°C. The optimization revealed that needed to achieve a maximum COP which was more than that for a maximum ECOP. Therefore, this investigation provides criteria to select low grade heat source temperature. Most of the series flow of the cases of cooling water from the condenser to the absorber was found to be better than the absorber to the condenser.

关键词： ionic liquid driven absorption cycle     H2O-[mmim][DMP]     coefficient of performance (COP)     exergy analysis     thermodynamics mixture property    

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Theoretical analysis and actual experimental research on static characteristics of suspendome structure

CHEN Zhihua, YAN Xiangyu, SUN Ruirui, FENG Zhenchang, QIN Yali, ZHAO Jianbo

《结构与土木工程前沿（英文）》 2007年 第1卷 第3期   页码 286-292 doi: 10.1007/s11709-007-0037-8

摘要： The suspendome used as the roof of the VIP hall in Tianjin Museum was analyzed by ANASYS under the assumptions of hinged joints and rigid joints in up chord, respectively, and the results show that the member force and nodal displacement under the two assumptions have little difference. Thus, it is attained that the suspendome can be analyzed with the assumption of hinged joints. A full-scale test on the suspendome with half-cable and half-pipe was carried out. The loading system, arrangement of measuring points, and the test procedures are introduced. Also, a test on steel wire ropes for elastic module was carried out. The experimental and theoretical values of member forces and nodal displacements were compared and it showed that they accord well with each other under low-level load. While under high-level load, the experimental value was bigger than the theoretical value due to the influence of the test environment. With the increase of the load, tension of outside cables and looseness of inside cables occurred, which indicated that the prestressing value in inside cables should be properly assigned. Both the experimental and theoretical results verify that the suspendome has a wide application prospect with the advantages of perfect mechanical characteristics, low steel consumption, convenient construction and low cost.

关键词： Tianjin     influence     displacement     high-level     low-level    

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基于实际工作状态的多跨悬索桥中间塔静力试验模型设计

吉林,王陶,吴寒亮

《中国工程科学》 2012年 第14卷 第5期   页码 66-70

摘要：

与传统两塔悬索桥相比，多塔连跨悬索桥中间塔的约束条件、工作环境及荷载作用等均有较大差别，其对全桥安全性和使用性有显著影响。基于泰州大桥的实际工作状态（中间塔的纵向最不利工况），采用静力相似理论设计中间塔缩尺模型。通过对原桥中间塔和试验模型的数值仿真分析，从内力、位移及应变等方面比较分析原桥和试验模型的相似关系，结果表明，以几何尺寸和材料弹性模量为基本相似量所设计的试验模型，能满足中间塔主要静力性能的试验要求。

关键词： 悬索桥     中间塔     实际工作状态     相似理论     数值仿真     模型试验    

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RETRACTED ARTICLE: Momentum exchange coefficient for two jet flows mixing in a tee junction

《化学科学与工程前沿（英文）》 2023年 第17卷 第12期   页码 2161-2161 doi: 10.1007/s11705-009-0143-3

摘要： RETRACTED ARTICLE: Momentum exchange coefficient for two jet flows mixing in a tee junction

关键词： tee junction     Momentum exchange coefficient     RETRACTED    

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Experimental study of heat transfer coefficient with rectangular baffle fin of solar air heater

Foued CHABANE,Nesrine HATRAF,Noureddine MOUMMI

《能源前沿（英文）》 2014年 第8卷 第2期   页码 160-172 doi: 10.1007/s11708-014-0321-y

摘要： This paper presents an experimental analysis of a single pass solar air collector with, and without using baffle fin. The heat transfer coefficient between the absorber plate and air can be considerably increased by using artificial roughness on the bottom plate and under the absorber plate of a solar air heater duct. An experimental study has been conducted to investigate the effect of roughness and operating parameters on heat transfer. The investigation has covered the range of Reynolds number from 1259 to 2517 depending on types of the configuration of the solar collectors. Based on the experimental data, values of Nusselt number have been determined for different values of configurations and operating parameters. To determine the enhancement in heat transfer and increment in thermal efficiency, the values of Nusselt have been compared with those of smooth duct under similar flow conditions.

关键词： Nusselt number     flow rate     heat transfer     heat transfer coefficient     thermal efficiency     forced convection    

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A photolysis coefficient for characterizing the response of aqueous constituents to photolysis

David R. HOKANSON,Ke LI,R. Rhodes TRUSSELL

《环境科学与工程前沿（英文）》 2016年 第10卷 第3期   页码 428-437 doi: 10.1007/s11783-015-0780-3

摘要： UV photolysis and UV based advanced oxidation processes (AOPs) are gaining more and more attention for drinking water treatment. Quantum yield ( ) and molar absorption coefficient ( ) are the two critical parameters measuring the effectiveness of photolysis of a compound. The product of the two was proposed as a fundamental measure of a constituent’s amenability to transformation by photolysis. It was shown that this product, named the photolysis coefficient, , can be determined using standard bench tests and captures the properties that govern a constituent’s transformation when exposed to light. The development showed the photolysis coefficient to be equally useful for microbiological, inorganic and organic constituents. Values of calculated by the authors based on quantum yield and molar absorption coefficient data from the literature were summarized. Photolysis coefficients among microorganisms ranged from 8500 to more than 600000 and are far higher than for inorganic and organic compounds, which varied over a range of approximately 10 to 1000 and are much less sensitive to UV photolysis than the microorganisms.

关键词： UV photolysis     disinfection     advanced oxidation     N-nitrosodimethylamine     quantum yield     absorption coefficient    

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Hyperbranched magnetic polymer: highly efficient removal of Cr(VI) and application in electroplating wastewater

《化学科学与工程前沿（英文）》 2023年 第17卷 第10期   页码 1568-1580 doi: 10.1007/s11705-023-2303-2

摘要： By using a two-step hydrothermal method and trithiocyanuric acid (TTCA), 2,4,6-trihydrazino-1,3,5-triazine (THT), and Fe3O4 as raw materials, a spherical magnetic adsorbent polymer (TTCA/THT@Fe3O4) was synthesized to achieve the efficient removal of Cr(VI) from wastewater. Under optimal adsorption conditions, the maximum adsorption capacity of TTCA/THT@Fe3O4 for Cr(VI) can reach 1340 mg∙g‒1. Notably, the removal efficiency can approach 98.9%, even at the lower concentration of 20 mg∙L‒1 Cr(VI). For actual wastewater containing Cr(VI), the Cr(VI) concentration was reduced from 25.8 to 0.4 mg∙L‒1, a remarkable 20% lower than the current industry discharge standard value. A mechanism for the high adsorption performance of Cr(VI) on TTCA/THT@Fe3O4 was investigated using Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and density functional theory. It can be plausibly attributed to the formation of Cr/N and Cr/S coordination bonds. Additionally, surface electrostatic adsorption, reduction effects, and the spherical polymer structure increase the contact area with Cr(VI), maximizing adsorption. The synergistic effect of adsorption and reduction enhances the adsorption performance of TTCA/THT@Fe3O4 for Cr(VI) and total chromium in water. The resultant polymer has a simple preparation process, excellent adsorption performance, easy magnetic separation, and promising application for actual wastewater.

关键词： magnetic polymer     chromium removal     hydrogen bonding     recyclability     actual wastewater    

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标题 作者 时间 类型 操作

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

Shilei LU,Zhe CAI,Li ZHANG,Yiran LI

期刊论文

Compressor performance of two-stage turbocharging system

HE Yituan, MA Chaochen, WEI Mingshan, ZHU Zhifu, HE Yituan

期刊论文

Performance of rolling piston type rotary compressor using fullerenes (C70) and NiFe

Ruixiang WANG,Yihao ZHANG,Yi LIAO

期刊论文

Nonlinear design-point performance adaptation approaches and their comparisons for gas turbine applications

Y. G. LI, P. PILIDIS,

期刊论文

建设项目协调管理绩效评价

郭峰,刘慧

期刊论文

Integration of renewable energies, flexible loads and storages into the German power grid: Actual situation

Harald SCHWARZ, Xiaoshu CAI

期刊论文

Impact of renewable energies on the operation and economic situation of coal fired power stations: Actual

Hans-Joachim KRAUTZ, Alexander LISK, Joachim POSSELT, Christian KATZER

期刊论文

Experimental study on performance of passive and active solar stills in Indian coastal climatic condition

R. LALITHA NARAYANA, V. RAMACHANDRA RAJU

期刊论文

Comprehensive performance analysis and optimization of 1,3-dimethylimidazolylium dimethylphosphate-water

Gorakshnath TAKALKAR, Ahmad K. SLEITI

期刊论文

Theoretical analysis and actual experimental research on static characteristics of suspendome structure

CHEN Zhihua, YAN Xiangyu, SUN Ruirui, FENG Zhenchang, QIN Yali, ZHAO Jianbo

期刊论文

基于实际工作状态的多跨悬索桥中间塔静力试验模型设计

吉林,王陶,吴寒亮

期刊论文

RETRACTED ARTICLE: Momentum exchange coefficient for two jet flows mixing in a tee junction

期刊论文

Experimental study of heat transfer coefficient with rectangular baffle fin of solar air heater

Foued CHABANE,Nesrine HATRAF,Noureddine MOUMMI

期刊论文

A photolysis coefficient for characterizing the response of aqueous constituents to photolysis

David R. HOKANSON,Ke LI,R. Rhodes TRUSSELL

期刊论文

Hyperbranched magnetic polymer: highly efficient removal of Cr(VI) and application in electroplating wastewater

期刊论文