Design of water distribution networks using particle swarm optimization

Application of particle swarm optimization (PSO) is demonstrated through design of a water distribution pipeline network. PSO is an evolutionary algorithm that utilizes the swarm intelligence to achieve the goal of optimizing a specified objective function. This algorithm uses the cognition of individuals and social behaviour in the optimization process. For the optimization of water distribution system, a simulation – optimization model, called PSONET is developed and used in which the optimization is by PSO. This formulation is applied to two benchmark optimization design problems. The results are compared with the results obtained by other optimization methods. The results show that the PSO is more efficient than other optimization methods as it requires fewer objective function evaluations.     

供热管网中旁通管动能的数值模拟分析

本文在瞬变流理论的基础上,根据供热管网的结构特点,对供热管网的模型进行了简化,提出了便于瞬变流分析数值模拟的简化模型.经过模拟分析发现,水泵处的旁通管装置对削减供热管网水锤的影响有显著作用,且当旁通管选择不同管径时,对供热管网水锤的削减作用不同.而后,本文对供热管网旁通管不同管径时的情况进行了数值模拟,通过比较不同管径下的模拟结果发现,大管径对减小水锤压力有很大作用,但考虑到经济性和止回阀的正常开启作用,不宜选用过大直径的旁通管.最后确定了某一系列管网的旁通管直径的选用原则,为供热管网系统的设计提供一定的参考.     

Optimal transient network rehabilitation using multi-objective ant colony optimization algorithm

ABSTRACT

In this paper, the problem of optimal rehabilitation of water distribution networks (WDNs) for both steady and transient state is investigated. Two objectives are considered in this study: minimizing rehabilitation cost by considering pipe size diameters as decision variables and minimizing the transient impacts by minimizing a surge damage potential factor (SDPF). A multi-objective ant colony optimization (MOACO) model is developed to solve this problem. The developed model is verified using the well-known New York City tunnel network. The application is carried out to modify an existing real WDN in New Cairo district designed in steady-state conditions to cope with the transient condition. The advantage of this study is to produce a set of solutions that help decision makers to identify the suitable approach, while evaluating and aggregating the preferences over multiple objective functions.     

优选管径法在给水管网优化设计中的应用

提出应用优选管径法（枚举技术）进行给水管网系统的优化设计计算，并编写ＷＤＯＣ软件系统进行实现。分析了我国目前给水管网系统设计、运行中存在的问题，并对标准优化技术没有在实际工作中广泛应用的原因进行分析，进一步介绍了优选管径法的技术处理和实现过程，最后以算例的形式对这一技术进行应用校核。结果表明，这一技术可完全应用于给水管网系统的新建、改扩建工程当中。     

A novel approach for optimal chiller loading using particle swarm optimization

This study employs two new methods to solve optimal chiller loading (OCL) problem. These methods are continuous genetic algorithm (GA) and particle swarm optimization (PSO). Because of continuous nature of variables in OCL problem, continuous GA and PSO easily overcome deficiencies in other conventional optimization methods. Partial load ratio (PLR) of the chiller is chosen as the variable to be optimized and consumption power of the chiller is considered as fitness function. Both of these methods find the optimal solution while the equality constraint is exactly satisfied. Some of the major advantages of proposed approaches over other conventional methods can be mentioned as fast convergence, escaping from getting into local optima, simple implementation as well as independency of the solution from the problem. Abilities of proposed methods are examined with reference to an example system. To demonstrate these abilities, results are compared with binary genetic algorithm method. The proposed approaches can be perfectly applied to air-conditioning systems.     

Optimal design of district heating and cooling pipe network of seawater-source heat pump

The district heating and cooling (DHC) system of a seawater-source heat pump is large system engineering. The investments and the operational cost of DHC pipe network are higher than a tradition system. Traditional design methods only satisfy the needs of the technology but dissatisfy the needs of the economy, which not only waste a mass of money but also bring problems to the operation, the maintenance and the management. So we build a least-annualized-cost global optimal mathematic model that comprises all constrict conditions. Furthermore, this model considers the variety of heating load and cooling load, the operational adjustment in different periods of the year. Genetic algorithm (GA) is used to obtain the optimal combinations of discrete diameters. Some operators of GA are selected to reduce the calculation time and obtain good calculation accuracy. This optimal method is used to the design of the DHC network of Xinghai Bay commercial district which is a real engineering. The design optimization can avoid the matter of the hydraulic unbalance of the system, enhance the running efficiency and greatly reduce the annualized-cost comparing with the traditional design method.     

Sensor system design for building indoor air protection

Many new biological and chemical sensors have been or are continuously being developed for infrastructure and environmental protection, e.g., for protecting the quality of water and indoor and outdoor air. However, there is a lack of fundamental system-level research leading to the development of sensor networks that both maximize protection and minimize the system cost for indoor air protection. Four key parameters are usually used to evaluate sensor performance: sensor sensitivity, probability of correct detection, false positive rate, and response time. The optimal design of a sensor system is affected by the above sensor performance parameters. This paper describes a preliminary study to: (1) identify simplified simulation and optimization strategies that can be used for sensor system design; (2) examine the relationships between sensor location, sensitivity, and quantity, and (3) use both detection time and total occupant exposure as optimization objective functions for sensor system design. Common building attack scenarios, using a typical chemical and biological warfare (CBW) agent, are simulated for a small commercial building. Genetic algorithm (GA) is then applied to optimize the sensor sensitivity, location, and quantity, thus achieving the best system behavior while also reducing the total system cost. Assuming that each attack scenario has the same probability for occurrence, optimal system designs that account for the simulated possible attack scenarios are obtained.     

谈住宅建筑给水排水节能设计

从节能环保角度入手,探析了住宅建筑给排水节能设计的主要措施,分别从用水器具选用、管网布置、可再生能源利用、管材选择等方面引起重视,以期在满足使用功能的同时实现节能环保的目标。     

遗传算法在煤气管径优化中的应用研究

给出了管径优化的目标函数,然后应用遗传算法对燃气输配管网进行了管径优化,优化结果表明,遗传算法适合于管道优化这这一工程领域。     

Reliability-based design optimization with discrete design variables and non-smooth performance functions: AB-PSO algorithm

The purpose of reliability-based design optimization (RBDO) is to find a balanced design that is not only economical but also reliable in the presence of uncertainty. Practical applications of RBDO involve discrete design variables, which are selected from commercially available lists, and non-smooth (non-differentiable) performance functions. In these cases, the problem becomes an NP-complete combinatorial optimization problem, which is intractable for discrete optimization methods. Moreover, the non-smooth performance functions would hinder the use of gradient-based optimizers as gradient information is of questionable accuracy. A framework is presented in this paper whereby subset simulation is integrated with a new particle swarm optimization (PSO) algorithm to solve the discrete and non-smooth RBDO problem. Subset simulation overcomes the inefficiency of direct Monte Carlo simulation (MCS) in estimating small failure probabilities, while being robust against the presence of non-smooth performance functions. The proposed PSO algorithm extends standard PSO to include two new features: auto-tuning and boundary-approaching. The former feature allows the proposed algorithm to automatically fine tune its control parameters without tedious trial-and-error procedures. The latter feature substantially increases the computational efficiency by encouraging movement toward the boundary of the safe region. The proposed auto-tuning boundary-approaching PSO algorithm (AB-PSO) is used to find the optimal design of a ten-bar truss, whose component sizes are selected from commercial standards, while reliability constraints are imposed by the current design code. In multiple trials, the AB-PSO algorithm is able to deliver competitive solutions with consistency. The superiority of the AB-PSO algorithm over standard PSO and GA (genetic algorithm) is statistically supported by non-parametric Mann-Whitney U tests with the p-value less than 0.01.     

Optimal design of urban water supply pipe networks

This paper approaches the optimisation of looped water distribution networks supplied from one or more sources, according to demand variation. The pipe networks have concentrated outflows or uniform outflow along the length of each pipe. An optimisation model coupled with a computational iterative procedure of optimal discharges through pipes is developed on the basis of linear programming for the design of new or partially extended water distribution networks. The optimum solution obtained by this model consists of one or two pipe segments of different discrete sizes between each pair of nodes. The improved linear optimisation model guarantees a high reliability. Also, it is possible to take into account the network pipes with variable discharge on route. Additionally, the paper compares the linear optimisation model to some others, such as the classic model of economical velocities, the Moshnin model and a nonlinear model. This shows a good performance of the proposed model.     

滨河国际大厦给排水工程设计

对滨河国际大厦给排水工程设计进行了详细介绍,分别阐述了该项目的给水系统、排水系统及消防给水系统的具体设置及管材选用情况,对今后同类公共建筑给排水设计具有一定指导意义。     

Shortening the search time in optimization of water distribution networks

Various optimization techniques have been implemented for minimizing the costs associated with water distribution networks (WDNs). In this regard, meta-heuristic algorithms have represented the highest efficiency. One of the weaknesses of these algorithms is their high computational costs, which make their implementation sometimes impracticable for optimization of large real life WDNs. In this article an optimization model based on the ant colony optimization algorithm is presented for least cost design of WDNs. In the proposed model, ants select pipe diameters so that the energy loss per unit length of pipes will be in a specific range. In this model, the number of objective function evaluations is small. Two sample networks have been optimized using the proposed model. Obtained results show that the model presented in this article has a very low search time, which makes its implementation possible for large real-life WDNs.     

A relative-risk framework for evaluating transient pathogen intrusion in distribution systems

Hydraulic transients generate significant negative pressures in water systems that may cause intrusion of contaminated water from the environment into the pipe. This paper expands the consideration of transient intrusion events from their purely hydraulic aspects by developing a risk-based framework for comparing the relative risk-reduction achieved by alternative transient-intrusion mitigation strategies. Alternative strategies may be any combination of changes to system operation or surge controls that would reduce the potential for intrusion of contaminants from the soil-groundwater environment surrounding the pipe. A reference groundwater contamination is assumed, and intrusion volumes and time-varying pathogen concentrations are computed respectively using hydraulic transient and water quality models. Risk-based measures are proposed to provide quantitative assessments of the relative reduction in the risk of receptor infection achieved by alternative mitigation strategies.     

基于管道直径的供水管网故障率分析

本文通过分析某市供水管网近十年的爆漏数据、建立供水管道管径与故障率方程,得出了其故障率与管径大小呈负相关。从管厚、埋深、管材等因素方面,分析了管道爆漏事故发生的原因,进一步探讨了供水管网优化设计中管径各因素的影响。     

Hydraulic transient in residential buildings with a direct pump connection

This paper consists of an experimental and numerical study into transient behaviour in a residential building. The analysed effects occur by centrifugal pumps when they start with a direct supply (fixed-speed pumps are connected to the service pipe without an atmospheric tank). Direct supply increases the transient effect and places higher demands on the water main. The properties of such an installation were analysed using a hydraulic model in order to detect the most unfavourable scenario. The results were compared to experimental data. Basic hydraulics demonstrates that a pressure drop occurs during the start-up. The magnitude mainly depends on the pump capacity. But, numerical and field results show that other variables related to service pipe design could also negatively affect the pressure surge. The study provides water utilities with information about the influence of the different variables on pressure surge magnitude and basic design criteria to minimize these effects.     

黄杨泵站取水头部施工方案研究

对珠海市黄杨泵站取水工程中的施工技术方案进行了分析,针对不足之处结合工艺条件提出了优化设计方案。详细介绍了优化方案中的顶管法施工、水下开挖段管道设计和钢制取水头部设计,并结合工程实践对类似工程的施工提出建议。工程实践表明:这些施工技术的应用不仅缩短了工期、节省了投资而且降低了施工难度。     

Evolution of research on water leakage control strategies: where are we now?

ABSTRACT

This study provides an overview of the 21st century research trends for water leakage control strategies that focus on pressure management, active leakage control, pipe rehabilitation, asset management and District Metered Area (DMA) design. The biggest contribution comes from the research team in Italy, whilst the most active researcher is based in Greece. Research in this field has gained momentum from 2008 although a couple of studies have been conducted since 2000. Control strategies are receiving attention not only from academia but also from industrial players who are looking for technological advances by collaborating with academic institutions in research and development. The main strategy to reduce water leakage is the pressure management of water distribution systems using optimal settings of a pressure reducing valve installation. Despite available technologies, the commitment from the government, the water operators and the local consumers are the most important criterion for the effective implementation of water-leakage control strategies.     

供水管网优化研究概述

简述供水管网的优化设计建模和优化算法,重点介绍了供水管网的多目标优化设计及遗传算法用于供水管网的最优化理论,并针对该方法用于供水管网优化设计的缺点,提出了模拟退火遗传算法求解给水管网管径优化解的计算思路。     

基于全寿命周期的供热管网管径优化设计方法

结合供热管网现代优化算法和确定管径的传统方法,提出了一种管径优化设计方法。该方法首先根据水力计算确定几种可行的管径布置方案,然后根据全寿命周期内管网成本最低确定最优方案。实例分析表明,该方法省去了编程的麻烦,克服了传统管径选取的盲目性,达到了更加节能和便于实际应用的目的。