Energy and Hydraulic Performance-Based Management of Large-Scale Pressurized Irrigation Systems

Improving energy and hydraulic performance of large-scale pressurized irrigation is now perceived as a very pressing need, after large budgets have been allocated into systems modernization. This paper tackles this priority area by developing a management oriented multi-step methodology, that integrates different existing models, to sector the system according to the pressure requirements of the hydrants, and to regulate the pumping station for i) a fixed and a variable pressure head control, and for ii) an enhanced performance. When applied to an on-demand system in the Sinistra Ofanto irrigation scheme of Foggia (Italy), this integrated approach showed potential for energy saving under the optimal scenario of 49 %, and noticeable improvement in the system performance in terms of hydrant pressure heads, as compared to the actual conditions. The monetary assessment demonstrates that the achieved energy saving amounts to 23,636 Euros per irrigation season, 45 % among which are due to sectoring.     

Multi- Objective Optimal Design of on- Demand Pressurized Irrigation Networks

In the context of water as an economic good, from the use of water, one can derive a value, which can be affected by the reliability of supply. On-demand irrigation systems provide valuable water to skilled farmers who have the capacity to maximize economic value of water. In this study, simultaneous optimization of on-demand irrigation network layout and pipe sizes is considered taking into account both investment and annual energy costs. The optimization problem is formulated as a problem of searching for the upstream head value, which minimizes the total cost (investment and energy costs) of the system. The investment and annual energy costs are obtained in two separate phases. Max–Min ant system (MMAS) algorithm is used to obtain the minimum cost design considering layout and pipe diameters of the network simultaneously. Clement methodology is used to determine flow rates of pipelines at the peak period of irrigation requirements. The applicability of the proposed method is showed by re-designing a real world example from literature.     

Optimal Operation of Pressurized Irrigation Networks with Several Supply Sources

The evolution of water distribution systems to pressurized networks has improved water use efficiency, but also significantly increased energy consumption. However, sustainable irrigated agriculture must be characterized by the reasonable and efficient use of both water and energy. Irrigation sectoring where farmers are organized in turns is one of the most effective measures to reduce energy use in irrigation water distribution networks. Previous methodologies developed for branched irrigation networks with one single source node have resulted in considerable energy savings. However, these methodologies were not suitable for networks with several water supply points. In this work, we develop an optimization methodology (WEBSOM) aimed at minimizing energy consumption and based on operational sectoring for networks with several source nodes. Using the NSGA-II multi-objective genetic algorithm, the optimal sectoring operation calendar that minimizes both energy consumption and pressure deficit is obtained. This methodology is tested in the irrigation district of Palos de la Frontera (Huelva, Spain) with three pumping stations, showing that potential annual energy savings of between 20 % and 29 % can be achieved, thus ensuring full pressure requirements in nearly all hydrants, along with the total satisfaction of irrigation requirements.     

污水处理厂的能耗与能量的回收利用

污水处理成本构成中运行费用占很大比重 ,因而采用节能的处理工艺与设备 ,将污水污染质中所含的潜能加以回收利用 ,将是降低污水处理成本的重要措施。主要结合德国对众多污水处理厂的运行所做的调查与分析结果 ,论述污水处理厂运行的合理能耗、节能措施及有机污染物潜能的利用等。     

明渠结合有压管调水系统的水力瞬变计算

研究了明渠结合有压管调水系统水力瞬变的数值模拟,采用明渠非恒定流基本方程同时描述明渠的非恒定流和管道的有压汉,对有压流动采用了窄缝法求解,此外,研究了用非恒定流计算方法求解恒定流动,并提出了保证数值计算收敛的措施和方法,作为应用,模拟计算了正在修建的东深供水改造工程的恒定流和水力瞬为流。     

Energy Systems and Electrical Networks

Measures to reduce the magnitude of voltages induced during prolonged operating modes of influencing overhead transmission lines, and also to lower the magnitude and shorten the duration of short-lived induced voltages, which, in a number of cases, will permit use of the traditional sequence of work production on the lines during which several crews can work simultaneously on the line and line equipment at the substations, are discussed; here, no partitioning of the transmission line into electrically uncoupled sections is required. __________ Translated from élektricheskie Stantsii, No. 1, January, 2007, pp. 52–55.     

Methodology for Detecting Critical Points in Pressurized Irrigation Networks with Multiple Water Supply Points

The modernization processes of hydraulic infrastructures from old open channels to pressurized networks have increased water use efficiency along with a dramatic increase of energy consumptions. The significant energy requirements associated with the increment of the energy tariffs for irrigation involve higher production costs for farmers. Therefore, strategies to reduce energy consumption in irrigation districts are strongly demanded. Methodologies based on sectoring and critical points control have been applied to branched networks with a single water supply point, obtaining significant energy savings. In this work, a new critical point control methodology for networks with multiple sources has been developed: the WEPCM algorithm, which uses the NSGA-II multi-objective evolutionary algorithm to find the lowest energy consumption operation rule of a set of pumping stations connected to an irrigation network that satisfies the pressure requirements, when the critical points are successively disabled. WECPM has been applied to a real irrigation district in Southern Spain. The obtained results were compared with those achieved by the WEBSOM algorithm, developed for sectoring multiple source networks. The control of critical points by the replacement of two pipes and the installation of four booster pumps provided annual energy savings of 36 % compared to the current network operation. Moreover, the control of critical points was more effective than sectoring, obtaining an additional annual energy saving of 10 %.     

关于水能资源管理的三点看法

随着经济的快速发展和资源开发力度的加大,在水资源的开发利用过程中暴露出一些令人担心的问题,已经出现的问题在水电开发上表现得比较突出和集中。引起我们从思想认识和管理体制上对水能资源问题的思考。一是从资源管理的角     

齿墩内流消能工的水力及消能特性试验研究

齿墩是用于有压管道中的一种新型内流消能工,为了分析其水力特性和消能效果,通过物理模型试验,对体型优化后的齿墩内流消能工进行了研究。结果表明:3种面积收缩比齿墩内流消能工时均压强在齿墩段上游很稳定,在齿墩进口压强突然急剧降低并在距齿墩进口处降到最低,随后压强升高,在齿墩下游较远处趋于平稳。齿墩内流消能工的面积收缩比小时,时均压强降幅大,流量系数较小,过流能力也小;3种面积收缩比方案的水头损失系数在流量增大到一定程度后不再发生明显变化,当齿墩内流消能工的面积收缩比小时,水头损失系数降幅小,但水头损失系数的值大;当齿墩内流消能工的面积收缩比小时,其消能率大,消能效果最好。     

Potential Performance of Hydraulic State Estimation in Water Distribution Networks

Water Resources Management - Hydraulic State Estimation (HSE) is a suitable tool to gain real-time understanding of water supply systems. This technique enables to estimate the most likely...     

汉中市水能资源开发利用现状及对策

水电是可再生的洁净能源,积极发展水电是我国电力发展的基本方针。陕西省汉中市水能资源丰富,开发条件优越,但目前开发利用程度较低。在新时期,如何使汉中水能资源早开发、快开发,直接关系到县域经济的可持续发展和全面建设小康社会目标的实现。本文主要对汉中市水能资源开发现状、存在问题、未来发展建议进行了调查、分析。     

Optimal Design of Pressurized Irrigation Networks to Minimize the Operational Cost under Different Management Scenarios

The adoption of measures leading to higher efficiencies in the use of both water and energy in water distribution networks is strongly demanded. The methodology proposed combines a multi-objective approach and a financial analysis to determine de optimal design of pressurized irrigation networks which entails the minimization of both the investment cost and operational cost under three operating scenarios that incorporate energy saving strategies: 1- all hydrants operate simultaneously; 2- hydrants are grouped into sectors and irrigation turns are established; 3- the on-demand operation of the network is assumed. This methodology has been applied in a real irrigation network located in Southern Spain showing that the lowest overall design cost (investment and operational costs) is achieved in scenario 2. The comparison of the selected solutions in the three proposed scenarios with the current network design considering the total fulfillment of irrigation requirements showed that operational cost savings between 65% and 76% could be achieved.     

Multi-Objective Optimization Model Based on Localized Loops for the Rehabilitation of Gravity-fed Pressurized Irrigation Networks

Nowadays, some of the existing irrigation distribution networks (IDNs) are facing hydraulic performance problems, due partly to the ageing of pipe networks, initial design flaws, improper management or/and the increase in water demand. Rehabilitation of these networks may become an inevitable need to provide the best services to farmers. To this end, a comprehensive computer model was developed to assist planners and decision makers in the determination of the most cost-effective strategy for the rehabilitation of irrigation networks. This model incorporates an innovative algorithm for the automatic search of the best looping positions in the network. Two multi-objective optimizations were applied for the rehabilitation of a real medium-size network operating on-demand and by gravity, one included the looping option while the other excluded this option. The two Pareto fronts, associated with each optimization, clearly indicated that it is imperative to consider the localized loops option during the rehabilitation process as it provided superior cost-effective solutions. The comparison between two selected cases from each front showed that even though the two solutions offered the same magnitude of improvement to the network, a cost saving of about 77% is obtained by choosing the case with the looping option. The model developed in the framework of this work represents a powerful optimization tool for cost-effective rehabilitation of irrigation networks.     

Incorporating the Irrigation Demand Simultaneity in the Optimal Operation of Pressurized Networks with Several Water Supply Points

Network sectoring is one of the most effective measures to reduce energy consumption in pressurized irrigation networks. In this work, the previous model focused on the irrigation networks sectoring with several supply points (WEBSOM), which considered the simultaneous operation of all hydrants, has been improved by integrating an analysis of multiple random demand patterns and their effects on variability in hydrant pressure (extended WEBSOM). The extended WEBSOM has implied a multiobjective optimization, followed by a Montecarlo procedure to analyze different flow regimes using quality of service indicators, a novelty for multi-source pressurized irrigation networks. This innovation has involved energy savings ranging from 9 to 15 % with respect to the consideration of the concurrent operation of all hydrants, which rarely occurs in on-farm irrigation systems. These energy savings were associated with maximum values of pressure deficit of 21 and 34 % in the most critical hydrant with a deficit frequency of 27 and 36 % in the peak month. However, smaller and less frequent deficits were achieved in the rest of the months. Thus, substantial energy savings can be obtained in irrigation districts without significant losses in the service quality provided to farmers.     

水利工程消能设计科学性分析

介绍水闸消能设计更加科学的计算方法,使得水闸闸后消能设计计算更加贴近实际,解决问题。     

加强水能管理推进有序开发

一、认真学习贯彻<可再生能源法>,充分认识水能的战略作用和地位 水能是水资源不可分割的重要组成部分,是清洁可再生的绿色能源,具有独特的自然属性、社会属性和经济属性.水力发电是利用河流的势能,通过物理过程转换产生电能,经过人的劳动实现了使用价值向价值的过渡和转变.电能以其优良的特性,成为直接服务于社会、经济和大众的优质能源,是人、自然、社会和谐发展的具体体现.水力发电不污染环境,并且发电效率高,水电站的水库还具有防洪、灌溉、城乡供水和工业用水、养殖、旅游等多种功能,经济效益与社会效益都很高.尤其是小水电技术相对成熟,具有分散开发、就地成网、就地供电、供电成本低的特点,使得小水电成为可持续利用支持经济社会发展的朝阳产业,特别是在西部地区,很多地方把开发水能资源作为拉动区域经济社会发展的首选产业之一.     

液压挖掘机二则故障原因的分析及排除

在施工过程中,液压挖掘机经常会出现一些事故.分别对液压挖掘机主泵周围异常噪音故障及斗杆伸出不能收回二则故障的原因进行了分析,并介绍了其排除方法.     

加压液化输沙技术运用于“浑水水力分离清水装置”的数学模型选择

该文运用FLUENT软件,分别采用RNG k-ε紊流模型和RSM模型,使用多相流混合物计算模型对加压液化渗水孔作用于浑水水力分离清水装置的水沙两相三维流场进行了数值模拟。经计算得出了不同计算模型计算结果,与物理模型实验结果进行对比。通过对比分析,得出RNG k-ε模型能够较好的预报内部流场。研究成果为后期使用数值模拟的研究方法,完善加压液化输沙技术的结构参数提供了理论依据。     

Integration of Hydraulic and Water Quality Modelling in Distribution Networks: EPANET-PMX

Simulation models for water distribution networks are used routinely for many purposes. Some examples are planning, design, monitoring and control. However, under conditions of low pressure, the conventional models that employ demand-driven analysis often provide misleading results. On the other hand, almost all the models that employ pressure-driven analysis do not perform dynamic and/or water quality simulations seamlessly. Typically, they exclude key elements such as pumps, control devices and tanks. EPANET-PDX is a pressure-driven extension of the EPANET 2 simulation model that preserved the capabilities of EPANET 2 including water quality modelling. However, it cannot simulate multiple chemical substances at once. The single-species approach to water quality modelling is inefficient and somewhat unrealistic. The reason is that different chemical substances may co-exist in water distribution networks. This article proposes a fully integrated network analysis model (EPANET-PMX) (pressure-dependent multi-species extension) that addresses these weaknesses. The model performs both steady state and dynamic simulations. It is applicable to any network with various combinations of chemical reactions and reaction kinetics. Examples that demonstrate its effectiveness are included.