基于BP神经网络与改进遗传算法的泵站优化调度

通常泵组件的调节主要依靠工程师经验,难以保证水泵在所有时段内均高效运行,易造成能源浪费,对此提出了以效率模型为依据的泵站优化调度方法。为减小误差,使用泵站实际运行数据基于BP神经网络训练水泵特性。在此基础上,利用训练后的数据初始化种群,以泵站效率之和最小为目标,建立泵站优化调度数学模型,设定水量、压力和高效区等约束条件,采用改进的遗传算法求解水泵组合方案及各泵运行参数。结果表明,改进遗传算法对泵站调度的优化效果明显,可适用于泵站的优化节能运行。研究成果为泵站优化调度运行提供了一种新方法。     

M市供水泵站优化调度模型及应用

为降低城市供水泵站能耗、提高企业效益,以泵站运行费用最低为目标函数,建立泵站优化调度模型,使用遗传算法求解最优的水泵运行组合,在满足供水量与供水压力的前提下,使水泵均运行在高效段内,减少了能量浪费,并以M市供水系统为例测试了泵站优化调度模型,利用泵站优化调度程序优化了A、B水厂泵站的运行情况,并对比优化能耗与原运行状况的实际能耗。结果表明,A水厂节能效果不明显,B水厂节约能耗约为27.08%,两座水厂的总能耗低于优化前的能耗,节能约14.02%。泵站优化调度理论及其优化方案可在减少供水企业运营成本、提升供水企业服务和管理水平、改善管网水力条件等各方面发挥重要作用。     

基于龙格库塔算法的梯级泵站优化运行

梯级泵站在调水、灌溉与生态修复等建设中发挥了巨大作用。为提高梯级泵站运行效率、节约运行费用,结合某梯级泵站明渠引水工程,以总效率最高为目标建立了梯级泵站优化调度模型,提出了一种基于龙格库塔算法(RUN)的优化调度方法。计算结果表明,与该泵站现状运行方案相比,采用RUN算法计算所得方案可提高运行效率0.73%,节省运行费用271 195元/年,优于利用PSO、GA算法所得优化结果,证实了所提方法可良好地服务于梯级泵站优化运行。     

大岗坡——石台寺多级泵站群优化调度模型研究

运用大系统优化理论对大岗坡－－石台寺多级泵站群优化调度进行分析，建立了具有三层递阶结构的大系统分解－－协调、分解－－聚合模型，给出了唐河在不同来水量条件下水资源优化分配及泵站机组最优开机方案。     

茭陵泵站改造工程机组启动预试运行方案研究

针对茭陵泵站改造工程的特殊性,在机组试运行前进行预试运行方案研究.进行了运行参数测试、抽水能力检查、应急演练及供电能力测试等项工作,并分析处理了系统运行情况及存在问题,提出茭陵泵站工程试运行的方法、程序,达到了优化试运行方案的目的,确保工程项目目标的实现.     

基于遗传算法的地表水取水泵站优化调度

针对我国地表水取水泵站运行效率不高、能源浪费等问题,基于地表水取水泵站优化调度模型,利用遗传算法以泵站运行总功率最小为目标函数编写泵站优化调度程序,分别计算北方某水库地表水处于最低水位不同日供水量、常水位不同日供水量的系统工况下泵站运行功率。结果表明,地表水常水位运行情况下比日常运行方案节能3.8%。可见遗传算法编写的泵站优化程序有效可行。     

含潮汐电站的海岛微网多目标优化调度

潮汐能是一种蕴藏量巨大的可再生能源,且潮汐能发电具有周期性和可预见性。然而现有海岛供电方案中少有考虑海岛自身拥有这一良好的天然条件。提出了一种以潮汐发电为主,配合风电场、抽水蓄能电站以及柴油发电机组的孤网海岛供电方案。对潮汐电站、风电场、抽水蓄能电站以及柴油机组分别建模,考虑各自的运行状况和约束条件以及负荷需求,提出了海岛微网多能互补的优化调度的方案。通过对比多个不同的典型场景,验证了该方案及优化调度模型的可行性和有效性。 关键词： 海岛;潮汐发电;风电;抽水蓄能电站;优化调度     

含变频泵泵站动态规划优化模型的敏感性分析

泵站实际运行时的运行参数不一定能符合泵站最优数值,为研究模型实际运行的特征及相关参数的敏感性,基于已建立的含变频泵的泵站优化调度的能耗模型和日运行电费优化模型,采用全局敏感性分析Morris法,以瞬时流量、瞬时扬程及日调水量、日均扬程和峰谷最大最小流量为变量参数,改变其取值范围得到含变频泵的单级泵站对应敏感性参数下模型输出结果,并进行敏感性分析得到实际运行的特征。结果表明,能耗、电费、单位流量能耗和单位水量电费随瞬时流量、日调水量的增加而增加;能耗、电费随扬程的增加而增加,单位扬程能耗、单位扬程电费在设计扬程32.15m处最少,最节能,性价比最高;在不超过机组承受能力和满足各种运行条件的情况下,高峰时段能运行的最小流量越小,整个泵站日运行电费越低;低谷时段可运行的最大流量越大,整个泵站日运行电费越大。研究结果为全面了解泵站的实际运行特征及指导实际运行提供借鉴。     

含沙水流条件下夹马口泵站水泵特性参数研究

为分析含沙水流条件下夹马口泵站的水泵特性参数,以泵站在含沙水流条件下的多组实测数据为基础,采用Matlab软件进行曲线拟合,得到含沙水流条件下水泵工作参数计算的新模型。对比分析表明,新模型的计算结果比陕西机械学院水泵实验室提出的模型的计算结果更接近实测数据,更适用于夹马口泵站的实际情况。根据新模型模拟计算出了不同含沙量对应的泵站效率,并提出了优化调度方案。研究成果可为夹马口引黄泵站运行调度提供指导,对其他引黄泵站的水泵特性研究也有一定借鉴作用。     

基于改进遗传算法与动态规划的输水泵站日优化调度

针对我国泵站因不合理调度而导致经济效益不高的问题,基于存在多管道系统的输水泵站,考虑峰谷电价的影响,以日运行费用最小为目标,构建了泵站日经济优化模型,并以蒙开个河库连通工程二级泵站为例,基于组合变异的改进遗传算法、动态规划法,对定速节流调节、变频调节两种调节方式进行泵站日优化调度。结果表明,改进遗传算法适用于泵站优化调度问题;同时发现当机组实际工况点偏离设计工况点较远时,采用变频调节经济效益更高。     

Performance assessment of some ice TES systems

In this paper, a performance assessment of four main types of ice storage techniques for space cooling purposes, namely ice slurry systems, ice-on-coil systems (both internal and external melt), and encapsulated ice systems is conducted. A detailed analysis, coupled with a case study based on the literature data, follows. The ice making techniques are compared on the basis of energy and exergy performance criteria including charging, discharging and storage efficiencies, which make up the ice storage and retrieval process. Losses due to heat leakage and irreversibilities from entropy generation are included. A vapor-compression refrigeration cycle with R134a as the working fluid provides the cooling load, while the analysis is performed in both a full storage and partial storage process, with comparisons between these two. In the case of full storage, the energy efficiencies associated with the charging and discharging processes are well over 98% in all cases, while the exergy efficiencies ranged from 46% to 76% for the charging cycle and 18% to 24% for the discharging cycle. For the partial storage systems, all energy and exergy efficiencies were slightly less than that for full storage, due to the increasing effect wall heat leakage has on the decreased storage volume and load. The results show that energy analyses alone do not provide much useful insight into system behavior, since the vast majority of losses in all processes are a result of entropy generation which results from system irreversibilities.     

Effect of co-cultivation of Chlamydomonas reinhardtii with Azotobacter chroococcum on hydrogen production

Chlamydomonas reinhardtii cc124 and Azotobacter chroococcum bacteria were co-cultured with a series of volume ratios and under a variety of light densities to determine the optimal culture conditions and to investigate the mechanism by which co-cultivation improves H₂ yield. The results demonstrated that the optimal culture conditions for the highest H₂ production of the combined system were a 1:40 vol ratio of bacterial cultures to algal cultures under 200 μE m^?2 s^?1. Under these conditions, the maximal H₂ yield was 255 μmol mg^?1 Chl, which was approximately 15.9-fold of the control. The reasons for the improvement in H₂ yield included decreased O₂ content, enhanced algal growth, and increased H₂ase activity and starch content of the combined system.     

Exergetic evaluation of 5 biowastes-to-biofuels routes via gasification

This paper presents the exergy analysis results for the production of several biofuels, i.e., SNG (synthetic natural gas), methanol, Fischer–Tropsch fuels, hydrogen, as well as heat and electricity, from several biowastes generated in the Dutch province of Friesland, selected as one of the typical European regions. Biowastes have been classified in 5 virtual streams according to their ultimate and proximate analysis. All production chains have been modeled in Aspen Plus in order to analyze their technical performance. The common steps for all the production chains are: pre-treatment, gasification, gas cleaning, water–gas-shift reactions, catalytic reactors, final gas separation and upgrading. Optionally a gas turbine and steam turbines are used to produce heat and electricity from unconverted gas and heat removal, respectively. The results show that, in terms of mass conversion, methanol production seems to be the most efficient process for all the biowastes. SNG synthesis is preferred when exergetic efficiency is the objective parameter, but hydrogen process is more efficient when the performance is analyzed by means of the 1st Law of Thermodynamics. The main exergy losses account for the gasification section, except in the electricity and heat production chain, where the combined cycle is less efficient.     

液压系统常见的故障诊断及处理

任何工程机械式液压设备使用时出现故障是不可避免的。但是怎样确定故障的原因及找到好的解决方法，这是使用者最关心的问题。讲述了液压系统常见的故障及其排除方法。     

Economie d'énergie en trigénération

Trigeneration is defined as the production of three useful forms of energy—heat, cold and power—from a primary source of energy such as natural gas or oil. For instance, trigeneration systems typically produce electrical power via a reciprocating engine or gas turbine and recover a large percentage of the heat energy retained in the lubricating oil, exhaust gas and coolant water systems to maximize the utilization of the primary fuel. The heat produced can be totally or partially used to fuel absorption refrigerators. Therefore, trigeneration systems enjoy an inherently high efficiency and have the potential to significantly reduce the energy-related operation costs of facilities. In this paper, we describe a model of characterization of trigeneration systems trough the condition of primary energy saving and the quality index, compared to the separate production of heat, cold and power. The study highlights the importance of the choice of the separate production reference system on the level of primary energy saving and emissions reduction.     

Mineralogical characterization of the intraseam layers of Lofoi lignite deposits in Florina basin (western Makedonia,northwest Greece)

The mineralogical composition of intraseam layers from Lofoi lignite deposits (northwest Greece) is the subject of the present study. The samples were examined by means of X-ray diffraction (XRD), thermo-gravimetric (TG/DTG) and differential thermal analysis (DTA), and Fourier transform infrared (FT-IR) spectrometry. The clay minerals prevail in most samples, with illite-muscovite being the dominant phase, and kaolinite and chlorite being the other major clay components. No smectite was found. Quartz and feldspars, dominate in two cases. The studied materials are characterized as clays to clayey sands, showing significant similarities with the intraseam layers of the adjacent Achlada lignite deposits.     

Innovative methodologies in renewable energy: A review

This paper is concerned with innovative approaches to renewable energy sources computation methodologies, which provide more refined results than the classical alternatives. Such refinements provide additional improvements especially for replacement of fossil energy usages that emit greenhouse gas (GHG) into the atmosphere leading to climate change impact. Current knowledge gap among each renewable energy source calculation is rather missing fundamentals of plausible, rational, and logical explanations for the interpretation of results. In the literature, there are rather complicated and mechanically applicable methodologies, which require input and output measurement data match with missing physical explanations. The view taken in this review paper is to concentrate on quite plausible, logical, rational, and effectively applicable innovative energy calculation methodologies with simplistic fundamentals. For this purpose, a set of renewable energy methodological approaches is revisited with their innovative structures concerning solar, wind, hydro, current, and geothermal energy resources. With the increase in the renewable energy utilizations to combat the undesirable impacts of global warming and climate change, there is a need for better models that will include physical environmental conditions and data properties in the probabilistic, statistical, stochastic, logical, and rational senses leading to refined and more reliable estimations with application examples in the text. Finally, new research directions are also recommended for more refined innovative energy system calculations.     

Constrained Optimization of Heat Transfer from an Extended Surface

Two different zero‐order optimization techniques are used to maximize the rates of heat transfer from a fin assembly of a specified cost and in the shape of several annular fins that are mounted on a central stem. The problem is formulated to account for two‐dimensional steady‐state heat transfer that is limited by several inequality constraints. The dimensionless governing equations are used to identify the relevant decision variables. The number of fins making up the assembly is treated as an input parameter. A digital computer is used to determine the required temperature distributions and to implement the optimization search algorithms. Three different fin materials are assessed—aluminum, copper and carbon steel. Design optimizations of the extended surface assembly were made over a range of operating conditions, encompassing several different convection heat transfer coefficients that are representative of free and forced convection in air, and several different overall temperature differences between the substrate surface and air. A few recommendations based on trends in the predicted results are given. © 2013 Wiley Periodicals, Inc. Heat Trans Asian Res, 43(6): 504–521, 2014; Published online 3 October 2013 in Wiley Online Library ( wileyonlinelibrary.com/journal/htj ). DOI 10.1002/htj.21093     

CY6D78Ti型柴油机的开发研制

本文介绍了CY6D78Ti型柴油机的开发研制过程及现状,CY6D78Ti型柴油机能满足国内中、重型卡车和豪华客车市场对柴油机动力性、经济性、可靠性的需求。由于该机型的高档配置,保证了其排放达到欧Ⅱ标准,同时为进一步提高性能、降低排放,采用电控及高压共轨等技术手段搭建了平台。     

我国车用柴油机的技术现状及发展趋势

本文根据国内外信息和资料，分析了我国目前车用柴油机制造技术方面与国际水平所存在的差距，预测今后若千年内车用柴油机要向节能降耗、应用增压技术、提高可靠性、降低排放、采用电控技术方面发展，以尽快接近和赶上国际先进水平．