scholarly journals Extending the global gradient algorithm to unsteady flow extended period simulations of water distribution systems

2010 ◽  
Vol 13 (2) ◽  
pp. 167-180 ◽  
Author(s):  
Ezio Todini
Keyword(s):  
Unsteady Flow ◽  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Extended Period ◽  
Distribution Networks ◽  
Gradient Algorithm ◽  
Integration Time ◽  
Original Algorithm ◽  
Global Gradient Algorithm

This paper introduces an extension of the Global Gradient Algorithm (GGA) to directly solve unsteady flow problems arising from the presence of variable head water storage devices, such as tanks, in Extended Period Simulations (EPS) of looped water distribution networks (WDN). Such a modification of the original algorithm was motivated by the need to overcome oscillations and instabilities reported by several users of EPANET, a worldwide available package, which uses the GGA to solve the looped WDN equations. The set of partial differential equations describing the time and space behaviour of a water distribution system is here presented. It is shown how an unsteady flow GGA can be derived by simple modifications of the original steady-state GGA. The performances of the new algorithm, referred to as EPS-GGA, are compared with the results provided by EPANET on an extremely simplified example, the solution of which is qualitatively known. As opposed to EPANET which shows significant instabilities, the EPS-GGA is stable under a wide variety of increasing integration time intervals.

scholarly journals Using real options for an eco-friendly design of water distribution systems

2014 ◽  
Vol 17 (1) ◽  
pp. 20-35 ◽  
Author(s):  
João Marques ◽  
Maria Cunha ◽  
Dragan A. Savić
Keyword(s):  
Real Options ◽  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
System Development ◽  
Water Distribution Systems ◽  
Distribution Networks ◽  
Embodied Energy ◽  
Real Options Approach ◽  
Materials Used

This paper presents a real options approach to handling uncertainties associated with the long-term planning of water distribution system development. Furthermore, carbon emissions associated with the installation and operation of water distribution networks are considered. These emissions are computed by taking an embodied energy approach to the different materials used in water networks. A simulated annealing heuristic is used to optimise a flexible eco-friendly design of water distribution systems for an extended life horizon. This time horizon is subdivided into different time intervals in which different possible decision paths can be followed. The proposed approach is applied to a case study and the results are presented according to a decision tree. Lastly, some comparisons and results are used to demonstrate the quality of the results of this approach.

scholarly journals Development of a Binary Model for Evaluating Water Distribution Systems by a Pressure Driven Analysis (PDA) Approach

2020 ◽  
Vol 10 (9) ◽  
pp. 3029 ◽  
Author(s):  
Attilio Fiorini Morosini ◽  
Sina Shaffiee Haghshenas ◽  
Sami Shaffiee Haghshenas ◽  
Zong Woo Geem
Keyword(s):  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Distribution Networks ◽  
Water Distribution Networks ◽  
Classification Model ◽  
Group Method ◽  
Binary Model ◽  
Pressure Driven Analysis ◽  
Pressure Driven

Investigation of Water Distribution Networks (WDNs) is considered a challenging task due to the unpredicted and uncertain conditions in water engineering. When in a WDN, a pipe failure occurs, and shut-off valves to isolate the broken pipe to allow repairing works are activated. In these new conditions, the hydraulic parameters in the network are modified because the topology of the entire system changes. If the head becomes inadequate, the Pressure Driven Analysis (PDA) is the correct approach to evaluate the performance of water networks. Hence, in the present study, the water distribution system was evaluated in pressure-driven conditions for 100 different scenarios and then using a type of neural network called Group Method of Data Handling (GMDH) as a stochastic technique. For this purpose, several most notable parameters including the base demand, pressure, and alpha (the percentage of effective supplied flow) were calculated using simulations based on a PDA approach and applied to the water distribution network of Praia a Mare in Southern Italy. In the second stage, the output parameters were used in a developed binary classification model. Finally, the obtained results showed that the GMDH algorithm can be applied as a powerful tool for modeling water distribution networks.

scholarly journals Impact of variable speed pumps on water quality in distribution systems

Water SA ◽  
2018 ◽  
Vol 44 (3 July) ◽  
Author(s):  
Moustafa S Darweesh
Keyword(s):  
Water Quality ◽  
Distribution Systems ◽  
Water Distribution ◽  
Average Rate ◽  
Extended Period ◽  
Distribution Networks ◽  
Residual Chlorine ◽  
Variable Speed ◽  
Water Age ◽  
The Impact

Water quality has become a prominent issue in the study of water distribution networks. Variable speed pumps (VSPs) can control and improve the performance of water distribution systems. However, they may have effects on the water quality. The objective of this study was to investigate the impact of VSPs on water quality. The EPANET water quality simulator was applied for modelling water age and chlorine residual in a distribution network. In addition, intrusion of an active contaminant and analysis of leakage effects on residual chlorine concentration were performed through extended period simulations. Results indicate that VSPs may have negative impacts on water quality, including increased water age during low consumption times, and reduced disinfectant residuals at peak hours. In addition, the average rate of chlorine decay for fixed speed pumps (57%) is higher than that for VSPs (54%) when a conservative contaminant (sewage water) is considered.

scholarly journals Hydraulic performance Analysis of water supply distribution network using water GEM v8i

2021 ◽  
Author(s):  
Dessalegn Geleta Ebsa ◽  
Fekadu Fufa
Keyword(s):  
Water Supply ◽  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Distribution Network ◽  
Extended Period ◽  
Distribution Networks ◽  
Hydraulic Parameters ◽  
Water Conveyance ◽  
Negative Pressures

Abstract. The study evaluates the hydraulic analysis of water supply distribution network using water GEMS v8i. which used for modeling and Simulation of hydraulic parameters in the distribution networks. The hydraulic parameters which analyzed by using this software were junction pressure, velocity of water in networking system, and nodal demands and the overall result of water supply did not satisfied demand. The water distribution system has been analyzed for steady state and extended period simulation for the present population scenario for intermittent water supply using water Gems v8i. About 14 percent of the total number of nodes analyzed had negative pressures while 68 percent of the nodes had pressures less than the adopted pressure for the analysis. These negative pressures indicate that there is inadequate head within the distribution network for water conveyance to all the sections. In the same manner 85.6 percent of flow velocities in the pipes were within the adopted velocity while around 14.4 percent of the velocities exceeded the adopted velocity. The results in this study revealed that the performance of the water distribution system of under current demand is inefficient.

Experience in controlling Asellus aquaticus in water distribution systems

2001 ◽  
Vol 1 (2) ◽  
pp. 217-223
Author(s):  
A. Oleszkiewicz ◽  
M. Geringer d'Oedenberg ◽  
J. Chapman
Keyword(s):  
Surface Water ◽  
Peracetic Acid ◽  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems ◽  
Water Reservoir ◽  
Distribution Networks ◽  
Average Dose ◽  
Asellus Aquaticus

Asellus aquaticus is one of the nuisance organisms found in water distribution systems. Case studies of operations aimed at control of this crustacean and its disinfestation, carried out in two water distribution networks: in Pevensey Bay (Eastbourne, UK) and in Gdansk (Poland), are presented. Raw water reservoir receiving surface water was the source of infestation in Pevensey Bay. In Gdansk A. aquaticus probably penetrated the water distribution system with surface water getting into a leaky collecting well receiving groundwater from a chalk aquifer. The presence of organic matter in water entering the systems seemed to favour the infestation. Chemical treatment with pyrethrins (Pevensey Bay) and peracetic acid/hydrogen peroxide preparation (Gdansk) was used. The concentration of pyrethrins was 10 (g/dm3 and the average dose of peracetic acid was 4 mg/dm3. Both chemical treatments were found quite effective, however, some sections of the (much larger than Pevensey Bay) distribution network in Gdansk were not completely cleaned of the infestation.

scholarly journals The extension of EPANET source code to simulate unsteady flow in water distribution networks with variable head tanks

2012 ◽  
Vol 14 (4) ◽  
pp. 960-973 ◽  
Author(s):  
Diego Avesani ◽  
Maurizio Righetti ◽  
Davide Righetti ◽  
Paolo Bertola
Keyword(s):  
Differential Equations ◽  
Unsteady Flow ◽  
Water Distribution ◽  
Source Code ◽  
Distribution Networks ◽  
Gradient Algorithm ◽  
System Modelling ◽  
Numerical Representation ◽  
Minimum Level ◽  
Hydraulic Behaviour

This paper describes the modifications applied to EPANET, a public-domain water distribution system modelling software package, that does not correctly compute the hydraulics of a water distribution network (WDN) with variable tank heads in (slow) unsteady flow conditions. Firstly the methodology adopted to extend the Global Gradient Algorithm (GGA) implemented in the original EPANET source code to the Extended Period Simulation-GGA (EPS-GGA) is described. Then the convergence and stability conditions of the theta method, used for the discretisation in time of the set of differential equations describing the hydraulic behaviour of a WDN, are discussed. The reasons for EPS-GGA numerical stability are demonstrated and a fully implicit discretisation of differential equations (i.e. theta = 1) is suggested as the optimal choice as implicitly proposed in Giustolisi et al. but without theoretical justification. Both the modified and original versions of EPANET are applied to a particularly severe test case of a WDN. Moreover, the procedures for the correct numerical representation of the tanks' maximum and minimum level boundary conditions are developed and compared with previously proposed procedures. The modified version of EPANET source code does not show the significant instabilities which are evident in the original version, nor the lack of consistency due to the improper maximum and minimum level boundary condition schematisations formerly proposed in the scientific literature.

scholarly journals Community-Level Resource Development and Management, Part 1: A Transferable Approach to the Analysis of Community Water Distribution System Expansion

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Megan McWalter Richardson ◽  
Kendra V. Sharp
Keyword(s):  
Water Resources ◽  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution System ◽  
Distribution Networks ◽  
Community Level ◽  
Rural Tanzania ◽  
Open Source Software Package ◽  
Development And Management

Access to water is extremely important in schools around the world, where students spend most of their day. As schools expand, particularly in areas with limited water resources, it is necessary to develop and manage water resources to ensure their sustainability. In this article we describe a method of analyzing water piping distribution networks using an open-source software package that allows practitioners to model the increased demands on water distribution systems associated with school growth. The methodology was then applied to the case study of a community-level water distribution system in rural Tanzania. This method is valuable because it is both condensed and easy to follow for those in the field with or without technical backgrounds. Minimal tools are needed for practitioners to develop their own system models (only a GPS, tape measurer, bucket, stopwatch and access to a computer with the software downloaded). Overall, this condensed written resource is more accessible than others available to many practitioners and thus improves the ease of modeling for pre-planning and analysis of expansion or other water distribution system modifications.

Low-cost sensor system based on LoraWAN for monitoring water distribution systems

2020 ◽  
Author(s):  
Harald Roclawski ◽  
Thomas Krätzig ◽  
Benjamin Dewals ◽  
Laurent Vercouter ◽  
Aloysio Saliba ◽  
...  
Keyword(s):  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Low Cost ◽  
Water Distribution Systems ◽  
Field Tests ◽  
Distribution Networks ◽  
Laboratory Scale ◽  
Smart Sensors ◽  
The Internet

<p>In the research project Iot.H2O, which is funded under the Water JPI Joint Call 2017 IC4WATER, the potential of the Internet of Things concept is investigated for monitoring and controlling water distribution systems. Smart sensors are used which send data via LoraWAN to gateways which are connected to the Internet. The aim of the project is to use low-cost sensors and open-source software.</p><p>In the presentation, a prototype on a laboratory scale will be shown. The design of the monitoring system will be explained in detail and compared to the design of standard SCADA systems. Results on a pump test rig based on a laboratory scale will be shown as well as first results of field tests in a real water distribution system in Germany.</p><p>The presentation will also detail how data gathered through the smart sensors will be integrated into software modelling and optimization of water distribution systems. Combined with the new data, such tools offer a range of applications of practical relevance, such as the identification of optimal locations of micro-turbines for energy recovery in water distribution networks and the estimation of water demand throughout the network.</p>

scholarly journals Capacity reliability of water distribution systems

2013 ◽  
Vol 16 (3) ◽  
pp. 731-741 ◽  
Author(s):  
J. Vaabel ◽  
T. Koppel ◽  
L. Ainola ◽  
L. Sarv
Keyword(s):  
Power Factor ◽  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Distribution Networks ◽  
Power Capacity ◽  
Hydraulic Power ◽  
Reliability Indicator ◽  
S Factor ◽  
Surplus Power

Hydraulic power capacity of the water distribution network (WDN) is analyzed, and energetically maximum flows in pipes and networks are determined. The concept of hydraulic power for the analysis of WDN characteristics is presented. Hydraulic power capacity characterizes the WDN capacity to meet pressure and flow demands. A capacity reliability indicator called the surplus power factor is introduced for individual transmission pipes and for distribution networks. The surplus power factor s that characterizes the reliability of the hydraulic system can be used along with other measures developed to quantify the hydraulic reliability of water networks. The coefficient of the hydraulic efficiency ηn of the network is defined. A water distribution system in service is analyzed to demonstrate the s and ηn values in the water network in service under different demand conditions. In order to calculate the s factor for WDNs, a network resistance coefficient C was determined. The coefficient C characterizes overall head losses in water pipelines and is a basis for the s factor calculation. This paper presents a theoretical approach to determine the coefficient C through matrix equations.

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