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 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 Pumps as turbines (PATs) in water distribution networks affected by intermittent service

2013 ◽  
Vol 16 (2) ◽  
pp. 259-271 ◽  
Author(s):  
Valeria Puleo ◽  
Chiara Maria Fontanazza ◽  
Vincenza Notaro ◽  
Mauro De Marchis ◽  
Gabriele Freni ◽  
...  
Keyword(s):  
Energy Recovery ◽  
Water Distribution ◽  
Network Performance ◽  
Water Distribution Network ◽  
Distribution Networks ◽  
Monte Carlo Analysis ◽  
Gradient Algorithm ◽  
Baseline Scenario ◽  
Centrifugal Pumps ◽  
Operational Parameters

A hydraulic model was developed in order to evaluate the potential energy recovery from the use of centrifugal pumps as turbines (PATs) in a water distribution network characterized by the presence of private tanks. The model integrates the Global Gradient Algorithm (GGA), with a pressure-driven model that permits a more realistic representation of the influence on the network behaviour of the private tanks filling and emptying. The model was applied to a real case study: a District Metered Area in Palermo (Italy). Three different scenarios were analysed and compared with a baseline scenario (Scenario 0 – no PAT installed) to identify the system configuration with added PATs that permits the maximal energy recovery without penalizing the hydraulic network performance. In scenarios involving PAT on service connections, the specification of PAT operational parameters was also evaluated by means of Monte Carlo Analysis. The centralized solution with a PAT installed downstream of the inlet node of the analysed district, combined with local PATs on the larger service connections, proves to be the most energy-efficient scenario.

Harvesting Energy from Buried Infrastructure: current UKCRIC research

2020 ◽  
Author(s):  
Fleur Loveridge ◽  
Paul Shepley ◽  
Ross Stirling ◽  
Anil Yildiz
Keyword(s):  
Heat Pump ◽  
Green Infrastructure ◽  
Water Distribution ◽  
Waste Water Treatment ◽  
Distribution Networks ◽  
Structural Function ◽  
Urban Drainage ◽  
Included Trial ◽  
Hydraulic Behaviour ◽  
The Uk

<p>The UK Government has a commitment to reach net-zero emissions by 2050. Because 70% of heating comes from direct burning of natural gas, this target cannot be achieved without decarbonising the gas network. One of the best routes to decarbonise heating is through use of ground thermal energy storage coupled with ground source heat pump systems. However, heat pump systems retain high investments costs, mainly due to the expense of drilling dedicated ground heat exchangers (GHE) such as deep boreholes. One route to reducing these costs is to use buried infrastructure for simultaneous structural function and ground heat exchange. In the past deep foundations, embedded retaining walls and trial tunnels have all been used as GHE.  However, there is increasing interest in extending this approach to other shallow buried infrastructure, such as waste and drinking water distribution networks, and green infrastructure such as sustainable urban drainage and swales. </p><p>The UK Collabatorium for Research in Infrastructure and Cities (UKCRIC) is a consortium founded by thirteen universities to provide an integrated research capability with a mission to underpin the renewal, sustainment and improvement of infrastructure and cities in the UK and elsewhere. Under the auspices of UKCRIC, a pump priming project called PLEXUS has been carried out. One of the research challenges of PLEXUS has been to consider how much heating and cooling capacity can be obtained from using civil engineering infrastructure as GHE, and whether there are any risks to original structural function from the GHE operation.  The project has included trial experiments for (i) soil element thermo-mechanical and thermo-hydraulic behaviour, (ii) the operation of sustainable urban drainage under heat injection, (iii) heat transfer characteristics of a near full scale water pipe segment, (iv) effects of temperature change on the formation of fats, oils and greases in waste water treatment systems. This paper will present a summary of key findings from the project and identify challenges for implementation of this valuable thermal resource. </p>

Edge betweenness for water distribution networks domain analysis

2019 ◽  
Vol 22 (1) ◽  
pp. 121-131 ◽  
Author(s):  
Antonietta Simone ◽  
Francesco G. Ciliberti ◽  
Daniele B. Laucelli ◽  
Luigi Berardi ◽  
Orazio Giustolisi
Keyword(s):  
Water Distribution ◽  
Shortest Paths ◽  
Distribution Networks ◽  
Domain Analysis ◽  
Water Distribution Networks ◽  
Complex Network Theory ◽  
Topological Features ◽  
Hydraulic Behaviour ◽  
Centrality Metrics ◽  
Edge Betweenness

Abstract Complex network theory (CNT) studies the relevance of elements in networks using centrality metrics. From the CNT standpoint, water distribution networks (WDNs) are infrastructure networks composed by vertices, named nodes, connected to each other by edges, named pipes, that transfer water to customers following a transfer process based on shortest paths. The present paper proposes the domain analysis of several real WDNs using the edge betweenness in order to capture the hydraulic behaviour based on network structure, i.e., for understanding the role of topological features in the emergent hydraulic behaviour. The strategy is obtained by tailoring CNT studies and tools in order to (i) embed the different hydraulic roles of sources and demand nodes, (ii) move the classic concept of centrality from the nodes to the pipes, i.e., the technically relevant components for WDNs and (iii) include information related to the directional devices, because they constrain flow directions. Results show the usefulness of the novel WDN-tailored edge betweenness for the WDN domain analysis. Therefore, the metric can represent a useful tool for supporting WDNs analysis, design and management tasks.

A mathematical model to evaluate apparent losses due to meter under-registration in intermittent water distribution networks

2013 ◽  
Vol 13 (4) ◽  
pp. 914-923 ◽  
Author(s):  
M. De Marchis ◽  
C. M. Fontanazza ◽  
G. Freni ◽  
G. La Loggia ◽  
V. Notaro ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Water Distribution ◽  
Distribution Networks ◽  
Mediterranean Area ◽  
Water Shortage ◽  
Gradient Algorithm ◽  
Water Volume ◽  
Demand Model ◽  
Hydraulic Network ◽  
Water Meter

Apparent losses consist of water volume drawn from the network, consumed by users but not paid for. Those due to water meter under-registration were evaluated by means of a mathematical model able to analyse the complexity of intermittent supply systems with private tanks. This supply scheme is very common in the Mediterranean area where unexpected water shortage often happens and intermittent water supply is a common practice. In order to analyse such complex systems, a demand model, reproducing the effect of private tanks, and an apparent losses module were developed and coupled with an hydraulic network model based on the Global Gradient Algorithm (GGA). In distribution networks pressure reduction valves (PRVs) are often used by water utilities to control the pressure and reduce background losses. These practices could influence the performance of water meters. For this reason, a PRV model was implemented and integrated with the demand and the hydraulic network models to better estimate the effect of pressure management on real and apparent losses. The comprehensive model was applied to a real case study. The proposed modelling approach was used to identify regions of the network with high apparent losses. Furthermore, the model may be used to predict the results of a water meter replacement plan and of the installation of devices that could affect apparent losses.

An Advanced Software to Manage a Smart Water Network with Innovative Metrics and Tools Based on Social Network Theory

10.29007/gvnz ◽  
2018 ◽  
Author(s):  
Armando Di Nardo ◽  
Michele Di Natale ◽  
Anna Di Mauro ◽  
Eva Martínez Díaz ◽  
Jose Antonio Blázquez Garcia ◽  
...  
Keyword(s):  
Social Network ◽  
Network Theory ◽  
Water Distribution ◽  
Distribution Networks ◽  
Social Network Theory ◽  
Geographical Information ◽  
Water Network ◽  
Time Data ◽  
Water Losses ◽  
Operational Conditions

The recent development and applications of social network theory in many fields of engineering (electricity, gas, transport, water, etc.) allows both the understanding of networks and to improve their management. Social network theory coupled to the availability of real time data and big data analysis techniques can change drastically the traditional approaches to manage civil networks. Recently, some authors are working to apply this novel approach, based on social network theory, on the water distribution networks using: a) graph partitioning algorithms to define optimal district meter areas both for water losses identification and for water network protection, b) innovative topological, energy and hydraulic indices to analyze performance; and c) GIS (Geographical Information System) to provide a more effective display of results and to improve network behavior in specific operational conditions. In this paper, a novel release 3.5 of SWANP software, that implements all these features, was tested on a real large water network in Alcalá de Henares, Spain.

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