Open and closed loop pressure control for leakage reduction

Ulanicki, Bogumił; Bounds, Peter; Rance, J. P.; Reynolds, Laurie

doi:10.1016/s1462-0758(00)00048-0

Cited by 90 publications

(54 citation statements)

References 6 publications

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“…A sub-grid of a water supply network, also termed a "district metered area", is a part of the network between two nodes where the head pressure is controlled. This pressure is maintained constant or follows a certain schedule [2] to ensure that there is an optimal pressure distribution in all the branches downstream. This is normally ensured by pressure reducing valves (PRVs), but recent studies have proposed their replacement by turbines.…”

Section: Introductionmentioning

confidence: 99%

Energy Recovery Using Micro-Hydropower Technology in Water Supply Systems: The Case Study of the City of Fribourg

Samora

Manso

Franca

et al. 2016

Water

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Abstract:Water supply systems (WWSs) are one of the main manmade water infrastructures presenting potential for micro-hydropower.Within urban networks, local decentralized micro-hydropower plants (MHPs) may be inserted in the regional electricity grid or used for self-consumption at the local grid level. Nevertheless, such networks are complex and the quantification of the potential for micro-hydropower other than that achieved by replacing pressure reducing valves (PRVs) is difficult. In this work, a methodology to quantify the potential for hydropower based on the excess energy in a network is proposed and applied to a real case. A constructive solution is presented based on the use of a novel micro-turbine for energy conversion, the five blade tubular propeller (5BTP). The location of the MHP within the network is defined with an optimization algorithm that maximizes the net present value after 20 years of operation. These concepts are tested for the WSS in the city of Fribourg, Switzerland. The proposed solution captures 10% of the city's energy potential and represents an economic interest. The results confirm the location of PRVs as potential sites for energy recovery and stress the need for careful sensitivity analysis of the consumption. Finally, an expedited method is derived to estimate the costs and energy that one 5BTP can produce in a given network.

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Section: Introductionmentioning

confidence: 99%

Energy Recovery Using Micro-Hydropower Technology in Water Supply Systems: The Case Study of the City of Fribourg

Samora

Manso

Franca

et al. 2016

Water

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“…Once the optimization process is complete, it is possible to define for each installed valve a feedback rule based on the optimization results, see Ulanicki et al (2000). Therefore, valves can ultimately be operated through an on-line feedback control system.…”

Section: Case Studymentioning

confidence: 99%

Scalable Pareto set generation for multiobjective co-design problems in water distribution networks: a continuous relaxation approach

Pecci

Abraham

Stoianov

2016

Struct Multidisc Optim

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In this paper, we study the multiobjective codesign problem of optimal valve placement and operation in water distribution networks, addressing the minimization of average pressure and pressure variability indices. The presented formulation considers nodal pressures, pipe flows and valve locations as decision variables, where binary variables are used to model the placement of control valves. The resulting optimization problem is a multiobjective mixed integer nonlinear optimization problem. As conflicting objectives, average zone pressure and pressure variability can not be simultaneously optimized. Therefore, we present the concept of Pareto optima sets to investigate the trade-offs between the two conflicting objectives and evaluate the best compromise. We focus on the approximation of the Pareto front, the image of the Pareto optima set through the objective functions, using the weighted sum, normal boundary intersection and normalized normal constraint scalarization techniques. Each of the three methods relies on the solution of a series of single-objective optimization problems, which are mixed integer nonlinear programs (MINLPs) in our case. For the solution of each single-objective optimization problem, we implement a relaxation method that solves a sequence of nonlinear programs (NLPs) whose stationary points converge to a stationary point of the original MINLP. The relaxed NLPs have a sparse structure that come from the sparse water network graph constraints. In solving the large number of relaxed NLPs, sparsity is exploited by tailored techniques to improve the performance of the algorithms further and render the approaches scalable for large scale networks. The features of the proposed scalarization approaches are evaluated using a published benchmarking network model.

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“…with p denoting a vector of node pressures, α denoting a leakage exponent and κ denoting a vector of leakage coefficients, see Ulanicki et al (2000) for details. Note that in the GAMS implementation the variables describing pressure at nodes with non-zero leakage coefficient κ are constrained to be positive, whilst the leakage term in Eq.…”

Section: Connection Nodesmentioning

confidence: 99%

“…Reduction of leakage, hence savings of clean water, can be achieved by introducing pressure control algorithms, see e.g. Ulanicki et al (2000). Amount of energy used for pumping can be decreased through optimisation of pumps operation.…”

Section: Introductionmentioning

confidence: 99%

Pump schedules optimisation with pressure aspects in complex large-scale water distribution systems

Skworcow

Paluszczyszyn

Ulanicki

2014

Drink. Water Eng. Sci.

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Abstract. This paper considers optimisation of pump and valve schedules in complex large-scale water distribution networks (WDN), taking into account pressure aspects such as minimum service pressure and pressuredependent leakage. An optimisation model is automatically generated in the GAMS language from a hydraulic model in the EPANET format and from additional files describing operational constraints, electricity tariffs and pump station configurations. The paper describes in details how each hydraulic component is modelled. To reduce the size of the optimisation problem the full hydraulic model is simplified using module reduction algorithm, while retaining the nonlinear characteristics of the model. Subsequently, a nonlinear programming solver CONOPT is used to solve the optimisation model, which is in the form of Nonlinear Programming with Discontinuous Derivatives (DNLP). The results produced by CONOPT are processed further by heuristic algorithms to generate integer solution. The proposed approached was tested on a large-scale WDN model provided in the EPANET format. The considered WDN included complex structures and interactions between pump stations. Solving of several scenarios considering different horizons, time steps, operational constraints, demand levels and topological changes demonstrated ability of the approach to automatically generate and solve optimisation problems for a variety of requirements.

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Open and closed loop pressure control for leakage reduction

Cited by 90 publications

References 6 publications

Energy Recovery Using Micro-Hydropower Technology in Water Supply Systems: The Case Study of the City of Fribourg

Energy Recovery Using Micro-Hydropower Technology in Water Supply Systems: The Case Study of the City of Fribourg

Scalable Pareto set generation for multiobjective co-design problems in water distribution networks: a continuous relaxation approach

Pump schedules optimisation with pressure aspects in complex large-scale water distribution systems

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