Pressure Reducing Valves Research Articles

Hybrid Evolutionary Optimization/Heuristic Technique for Water System Expansion and Operation

AbstractThis paper presents a methodological solution to The Battle of Background Leakage Assessment for Water Networks (BBLAWN) competition. The methodology employs two constrained multiple-objective optimization problems and is implemented in the context of a software application for the generic hydraulic optimization and benchmarking of water distribution system (WDS) problems. The objectives are the combined infrastructure and operational costs and system-wide leakage, both to be minimized. In order to accelerate the evaluation of potential solutions, a distributed computing approach permits multiple EPANET solutions to be evaluated in parallel. A pressure-driven demand extension to EPANET assists the optimization in accurately ranking near-feasible solutions and to dynamically allocate leakage demand to nodes. Pressure-reducing valves (PRVs) have been located in two ways: a priori, with respect to the optimization analysis, and a posteriori after the infrastructure optimization to reduce excess press...

Multistep Approach for Optimizing Design and Operation of the C-Town Pipe Network Model

AbstractA multiobjective approach is used here to optimize design and operation of the C-Town pipe network, searching for trade-off solutions between (1) installation cost, (2) operational cost, and (3) cost of the pressure-reducing valves. Due to the large number of decisional variables and to the complexity of the constraints considered, the optimization problem was tackled in five steps: (1) identification of some feasible (on the basis of the many constraints) first attempt solutions; (2) application of a multiobjective genetic algorithm to the 2D optimization problem with objective functions 1 and 2, in order to obtain optimal trade-off solutions between the installation cost and operational cost, without considering the installation of pressure-reducing valves; (3) application of the multiobjective genetic algorithm to the optimization problem with objective functions 2 and 3 for each of the solution selected at the end of Step 2, in order to assess how the operational cost can decrease thanks to th...

Rehabilitation of a Water Distribution System Using Sequential Multiobjective Optimization Models

Identification of the optimal rehabilitation plan for a large water distribution system (WDS) with a substantial number of decision variables is a challenging task, especially when no supercomputer facilities are available. This paper presents an initiative methodology for the rehabilitation of WDS based on three sequential stages of multiobjective optimization models for gradually identifying the best-known Pareto front (PF). A two-objective optimization model is used in the first two stages where the objectives are to minimize rehabilitated infrastructure costs and operational costs. The optimization model in the first stage applies to a skeletonized WDS. The PFs obtained in Stage 1 are further improved in Stage 2 using the same two-objective optimization problem but for the full network. The third stage employs a three-objective optimization model by minimizing the cost of additional pressure reducing valves (PRVs) as the third objective. The suggested methodology was demonstrated through use of a real and large WDS from the literature. Results show the efficiency of the suggested methodology to achieve the optimal solutions for a large WDS in a reasonable computational time. Results also suggest the minimum total costs that will be obtained once maximum leakage reduction is achieved due to maximum possible pipeline rehabilitation without increasing the existing tanks.

Evaluation of Pressure Reducing Valves performance using Statistical Approach in Water Distribution System : Case Study

It has been widely accepted that the pressure management of water distribution systems using pressure reducing valves(PRVs) would be an effective method for controlling leakages. A pressure reducing valve (PRV) regulates outlet pressure regardless of fluctuating flow and varying inlet pressure, thereby reducing leakage and mitigating the stress on the water distribution system. However, the operation of a PRV is vulnerable to its mechanical condition and hydraulic operability. In this research, the effect of PRVs installed in water distribution system are evaluated in terms of hydraulic pressure reduction and mechanical performance by analyzing measured pressure data with statistical approach. A statistical approach using the moving average filter and frequency analysis based on fourier transform is presented to detect abnormally operated PRVs that have been densely installed in water distribution system. The result shows that the proposed approach can be a good performance evaluation method by simply measuring pressures for the PRVs.

Optimal design of an electro-hydraulic valve for heavy-duty vehicle clutch actuator with certain constraints

The main objective of this paper is to investigate the sensitivity analysis and optimal design of a proportional solenoid valve (PSV) operated pressure reducing valve (PRV) for heavy-duty automatic transmission clutch actuators. The nonlinear electro-hydraulic valve model is developed based on fluid dynamics. In order to implement the sensitivity analysis and optimization for the PRV, the PSV model is validated by comparing the results with data obtained from a real test-bench. The sensitivity of the PSV pressure response with regard to the structural parameters is investigated by using Sobol׳s method. Finally, simulations and experimental investigations are performed on the optimized prototype and the results reveal that the dynamical characteristics of the valve have been improved in comparison with the original valve.

Pressure Management and Electric Power Production Using Pumps as Turbines

Pressure‐reducing valves (PRVs) are widely used in a water distribution systems (WDSs) to reduce pressure. Replacing PRVs with pumps as turbines (PATs) allows for pressure control as well as electricity generation. In the first step of this study, optimal setting and placement of PRVs was determined to reduce leakage by using a genetic algorithm in a WDS in Tabriz province, Iran. In the second step, some of the selected PRVs were replaced with PATs. Thereafter, the amount of power that would be generated by PATs was calculated. Eventually the system was evaluated in order to validate the proposed model. The computational results show loss reduction and production of a remarkable amount of electric power in the studied system.

A Study on Cost Benefit Analysis Optimization Model for Water Distribution Network Rehabilitation Project of Taebaek Region

This research carried out an analysis on input cost and leakage reduction effect by leakage reduction method, focusing on the project for establishing an optimal water pipe network management system in the Taebaek region, which has been executed annually since 2009. Based on the result, optimal cost-benefit analysis models for water distribution network rehabilitation project were developed using DEA(data envelopment analysis) and multiple regression analysis, which have been widely utilized for efficiency analysis in public and other projects. DEA and multiple regression analysis were carried out by applying 4 analytical methods involving different ratios and costs. The result showed that the models involving the analytical methods 2 and 4 were of low significance (which therefore were excluded), and only the models involving the analytical methods 1 and 3 were suitable. From the result it was judged that the leakage management method to be executed with the highest priority for the improvement of revenue water ratio was installation of pressure reduction valve, followed by replacement of water distribution pipe, replacement of water supply pipe, and then leakage detection and repair; and that the execution of leakage management methods in this order would be most economical. In addition, replacement of water meter was also shown to be necessary in case there were a large number of defective water meters.

Successive Linear Programming Approach Applied to BBLAWN

AbstractThe battle of background leakage assessment for water networks (BBLAWN) challenge was approached using successive linear programming. A linear representation was solved successively for the nonlinear constraints of headloss, leakage, pump energy consumption, and pipe sizing. The optimization model returned minimal cost pump scheduling and pipe sizing while minimizing leakage and maintaining minimum service pressures to the consumers. Pressure reducing valves, pump, and water tank sizing were performed manually and their effect was examined using the optimization model. Parallel pipes were added along the main supply pipes from the pumping stations to the water tanks, to allow for minimum service pressures. Pressure reducing valves were added to pipes branching from the main supply pipes to lower excess pressures to the secondary supply pipes.

Assessing the results of a virtual pressure management project applied in Kos Town water distribution network

Water pressure management (PM) is one of the most cost-effective ways for a water utility to reduce water leakage, pipes’ bursts, improve the level of services provided to its customers and lower its operating expenses. The present paper presents a pilot pressure management project designed for the water distribution system of Kos Town (capital of Kos Island, Greece). Kos Town experiences extreme variations regarding its population served by the local water utility between summer and winter. The PM implementation was achieved by developing the system’s hydraulic simulation model using the commercial software, Watergems V8i. For the water demand allocation of the model, the spatial allocation of water demand at street level approach was used because the customers’ water meters were not geo-referenced. The results were compared to multiplicatively weighted Voronoi diagram method’s results and to field measurements. The simulation process took into account the respective demand patterns of the various types of urban water uses, considering the water volume being lost through leaks/breaks occurring in the pipe network, as a competitive use. Each kind of water used was divided into a pressure dependent part and a volume depended one. Both parts were introduced to the model. The designing phase of the PM included the formation of district metered areas and Pressure Reducing Valves (PRVs) installation. The reduction in pressure within acceptable regulation limits resulted in the reduced needs of System Input Volume (SIV), due to significant reduction of anticipated water losses and authorized consumption, as both these “water uses” are pressure dependent. There were many simulations of different scenarios in time (monthly) and PRVs’ configuration. Regarding the latter, several types of PRVs and their settings were tested (e.g. fixed PRVs; PRVs with modified daily pattern; PRVs combined with local pressure boosters). The virtual scenarios resulted in reducing the SIV up to 24%. The related water savings have a direct positive environmental impact on the aquifer supplying Kos Town. These outcomes persuaded the local water utility to proceed with the actual implementation of the pilot study by installing the necessary system devices (either for measuring data or for pressure reducing) in more than 40 manholes across the town.

A strategic assessment of micro-hydropower in the UK and Irish water industry: Identifying technical and economic constraints

Energy recovery using micro-hydropower (MHP) technology can enhance the sustainability of the water industry. This paper presents a structured four-step methodology for assessing potential energy recovery sites in water and wastewater infrastructure in regions of the UK and Ireland; at service reservoirs (SRVs), pressure reducing valves (PRVs) and wastewater treatment plants (WWTPs). Step 1 helped identify different all potential energy recovery sites in water and wastewater infrastructure. Step 2 shortlisted the most feasible sites for energy recovery, with the potential to generate an estimated 17.9 GWh per annum. Step 3 considered the technical and economic challenges relating to energy recovery and considered turbine selection, varying flow and site characteristics, feed-in tariffs (FITs) and overall project costs. Lastly, Step 4 provided evidence for the most feasible projects for Wales and Ireland based on capacity; larger than 3.6 or 18.2 kW at WWTP locations, 4.8 or 24.8 kW at PRVs and 12.8 or 22.2 kW at SRV sites, respectively. However, cheaper turbine technology and better financial incentives may improve the feasibility of smaller potential energy recovery sites. The results provide water companies with an estimated feasible capacity for potential energy recovery through MHP installations at different water and wastewater infrastructure sites.

Energy efficiency in a water supply system: Energy consumption and CO2 emission

This paper presents important fundamentals associated with water and energy efficiency and highlights the importance of using renewable energy sources. A model of multi-criteria optimization for energy efficiency based on water and environmental management policies, including the preservation of water resources and the control of water pressure and energy consumption through a hybrid energy solution, was developed and applied to a water supply system. The methodology developed includes three solutions: (1) the use of a water turbine in pipe systems where pressures are higher than necessary and pressure-reducing valves are installed, (2) the optimization of pumping operation according to the electricity tariff and water demand, and (3) the use of other renewable energy sources, including a wind turbine, to supply energy to the pumping station, with the remaining energy being sold to the national electric grid. The use of an integrated solution (water and energy) proves to be a valuable input for creating benefits from available hydro energy in the water supply system in order to produce clean power, and the use of a wind source allows for the reduction of energy consumption in pumping stations, as well as of the CO2 emission to the atmosphere.

Modelling aspects of a CNG injection system to predict its behavior under steady state conditions and throughout driving cycle simulations

Alternative fuels such as compressed natural gas (CNG) have lately gained an increasing interest due to the even more stringent emission regulations and environmental policies. Considerable R&D activity has been carried out in order to enhance the mixture formation and to improve the after treatment efficiency. The achievement of these goals cannot disregard the importance of the injection system and of its component (common rail, injectors and pressure reducing valve) on the air-to-fuel mixing. The amount of injected fuel should in fact be properly targeted by the ECU basing on the estimation of the induced air and accounting for the embedded closed-loop strategies. Still, these latter are normally derived from engine-base routines and totally ignore the injection system dynamics.The present paper aims at developing a thorough model of the injection system with specific attention to the one component which significantly contributes to fully defining its dynamic response, i.e. the pressure reducing valve. The pressure reducer is made up of various elements that retain diverse weights on the valve behavior and should consequently be differently addressed to. The research has been focused on defining the set of parameters to be precisely reproduced in the 0D-1D simulation so as to match the injection system experimental behavior. A refined model of the pressure reducer has hence been proposed and the model has been calibrated, tested and run under various operating conditions so as to assess for the set-up validity.Comparisons have been carried out on steady state points as well as through out a vehicle driving cycle and the model capability to properly reproduce the real system characteristic has been investigated into. The proposed valve model has proved to consistently replicate the injection system response for different speed and load conditions. A few methodological indications concerning modeling aspects of a pressure regulator can be drawn from the present study.Finally, the model has been run in a predictive mode so as to inquiry into the response of the system to fast transient operations, both in terms of speed and load. The model outputs have highlighted mismatches between the ECU target mass and the actually injected one and have hinted at the need for dedicated and refined control strategies capable of preventing anomalies in the mixture formation and hence in the engine functioning.

Pump as turbine implementation in a dynamic numerical model: cost analysis for energy recovery in water distribution network

In complex systems characterized by the presence of private tanks and water scarcity conditions, water managers usually apply intermittent distribution, trying to reduce the water volumes supplied to the users and pipe leakages, or use pressure reduction valves for controlling pressure in the network. The application of pumps as turbines (PATs) appears as an alternative and sustainable solution to either control network pressure or produce energy. In the present paper, the economic benefit of PAT application in water distribution networks was investigated in a small district of Palermo network (Italy). The analysis of energy recovery, carried out by means of a numerical model based on the method of characteristics, shows that PATs can lead to a very attractive economical benefit in terms of energy production.

캐비테이션 억제를 위한 감압밸브의 유로 형상에 관한 연구

본 연구에서는 공동 주택의 수전 개방 조건에서, 감압밸브 내부 오리피스 형상이 캐비테이션 발생에 미치는 영향에 대하여 살펴보았다. 이를 위하여 감압밸브 내부의 유로형상을 9가지 유형으로 구별하여 제시하고, 3차원 유한해석 코드인 ANSYS CFX를 사용하여 감압밸브 내의 유동해석을 수행하였다. 급격한 단면 변화가 일어나는 오리피스에서 최저 압력과 최대 속도가 발생하였다. 최대속도가 존재하는 부위에서 0 이상 증기체적비를 나타내어 캐비테이션이 발생함을 확

Transient Effects of Self-adjustment of Pressure Reducing Valves

Pressure control strategy through Pressure Reducing Valves (PRV) has been deeply investigated as management strategy, aimed at water leakages reduction avoiding very expensive pipe replacement programs. On the contrary, few experimental data are available in literature, with regard to PRV transient behavior in terms of its response to incoming pressure waves, as well as the time required for achieving the pressure set point. In this paper, the results of some experimental tests are presented. The PRV is installed in a single high density polyethylene pipe and transients are generated by operating the downstream end valve. Two types of tests are considered: a partial valve closure and opening simulating a water demand decrease and increase, respectively. The analysis of the experimental pressure traces points out the valuable effects of the PRV on transient characteristics with respect to the case of a partially closed in-line valve with a constant opening degree.

Experimental Investigation of Resilience and Pressure Management in Water Distribution Networks

An extensive experimental investigation into the pressure management and resilience of three water distribution network configurations is conducted including: fixed topology zones with fixed outlet pressure reducing valves (PRV), fixed topology zones with flow modulating PRVs, and a dynamic topology. Hydraulic data (128S/s) captures the network behaviour under normal conditions and failure, including artificial bursts generated by operating hydrants and a real burst that affected 8,000 properties. Under normal operation, a dynamic topology lowered pressure by 3.1% over a fixed topology with flow modulating PRVs. A dynamic topology maintained the supply of 1,400 properties during the real burst incident.

Measurements and Analysis of Cavitation in a Pressure Reducing Valve During Operation – a Case Study

Abstract This paper proposes a methodology and presents its practical application for evaluating whether a pressure reducing valve (PRV) is under cavitation during its operation in a water distribution system. The approach is based on collecting measurements over a 24-hour period such that high demand and low demand times are included. The collected measurements allow evaluation of four indicators related to cavitation, namely the hydraulic cavitation index, noise generated by the valve, acoustic cavitation index and the spectra of the noise. These four indicators provide sufficient information for diagnosis of cavitation with high certainty.

Leakage Management: Planning Remote Real Time Controlled Pressure Reduction in Oppegård Municipality

Pressure control entails the cheapest technical solution to achieve leakage reduction in water distribution networks in short-medium time horizon. This work reports the planning of remote real time controlled (RRTC) pressure reducing valves (PRV) for the Oppegård (Norway) hydraulic network. It was achieved by using an advanced hydraulic model which integrates the pressure-dependent background leakage model with the simulation of PRVs based on remote control nodes. Results demonstrate that RRTC PRVs instead of existing locally controlled ones permits the reduction of the background leakages of about 35%. This rate increases over 40% if few additional RRTC PCV are installed.

Optimized Control of Pressure Reducing Valves in Water Distribution Networks with Dynamic Topology

A dynamic topology aggregates zones in water distribution networks (WDNs) for improved pressure management and resilience to failure. Based on a sequential convex programming (SCP) approach, we propose an optimization method for the control of pressure reducing valves (PRV) in WDNs with dynamic topology. By restricting the SCP iterations to the feasible search space, we show that reliable convergence of the method is achieved. Using an experimental study in a large operational network, the optimization of PRV settings with a dynamic topology is shown to result in pressure reductions of 3.7% compared to optimized PRVs in a closed DMA structure.

Hydropower Potential in Water Distribution Networks: Pressure Control by PATs

Pressure control is one of the main techniques to control leakages in Water Distribution Networks (WDNs) and to prevent pipe damage, improving the delivery standards of a water supply systems. Pressure reducing stations (PRSs) equipped by either pressure reducing valves or motor driven regulating valves are commonly used to dissipate excess hydraulic head in WDNs. An integrated new technical solution with economic and system flexibility benefits is presented which replaces PRSs with pumps used as turbines (PATs). Optimal PAT performance is obtained by a Variable Operating Strategy (VOS), recently developed for the design of small hydropower plants on the basis of valve time operation, and net return determined by both energy production and savings through minimizing leakage. The literature values of both leakages costs and energy tariffs are used to develop a buisness plan model and evaluate the economic benefit of small hydropower plants equipped with PATs. The study shows that the hydropower installation produces interesting economic benefits, even in presence of small available power, that could encourage the leakage reduction even if water savings are not economically relevant, with consequent environmental benefits.