Research

1336 KiB

Open AccessArticle

Experimental and Numerical Analysis of a Water Emptying Pipeline Using Different Air Valves

by Oscar E. Coronado-Hernández, Vicente S. Fuertes-Miquel, Mohsen Besharat and Helena M. Ramos

Water 2017, 9(2), 98; https://doi.org/10.3390/w9020098 - 08 Feb 2017

Cited by 39 | Viewed by 6949

The emptying procedure is a common operation that engineers have to face in pipelines. This generates subatmospheric pressure caused by the expansion of air pockets, which can produce the collapse of the system depending on the conditions of the installation. To avoid this [...] Read more.

The emptying procedure is a common operation that engineers have to face in pipelines. This generates subatmospheric pressure caused by the expansion of air pockets, which can produce the collapse of the system depending on the conditions of the installation. To avoid this problem, engineers have to install air valves in pipelines. However, if air valves are not adequately designed, then the risk in pipelines continues. In this research, a mathematical model is developed to simulate an emptying process in pipelines that can be used for planning this type of operation. The one-dimensional proposed model analyzes the water phase propagation by a new rigid model and the air pockets effect using thermodynamic formulations. The proposed model is validated through measurements of the air pocket absolute pressure, the water velocity and the length of the emptying columns in an experimental facility. Results show that the proposed model can accurately predict the hydraulic characteristic variables. Full article

(This article belongs to the Special Issue Water Systems towards New Future Challenges)

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3645 KiB

Open AccessEditor’s ChoiceArticle

Energy Recovery in Existing Water Networks: Towards Greater Sustainability

by Modesto Pérez-Sánchez, Francisco Javier Sánchez-Romero, Helena M. Ramos and P. Amparo López-Jiménez

Water 2017, 9(2), 97; https://doi.org/10.3390/w9020097 - 08 Feb 2017

Cited by 106 | Viewed by 9558

Abstract

Analyses of possible synergies between energy recovery and water management are essential for achieving sustainable improvements in the performance of irrigation water networks. Improving the energy efficiency of water systems by hydraulic energy recovery is becoming an inevitable trend for energy conservation, emissions [...] Read more.

Analyses of possible synergies between energy recovery and water management are essential for achieving sustainable improvements in the performance of irrigation water networks. Improving the energy efficiency of water systems by hydraulic energy recovery is becoming an inevitable trend for energy conservation, emissions reduction, and the increase of profit margins as well as for environmental requirements. This paper presents the state of the art of hydraulic energy generation in drinking and irrigation water networks through an extensive review and by analyzing the types of machinery installed, economic and environmental implications of large and small hydropower systems, and how hydropower can be applied in water distribution networks (drinking and irrigation) where energy recovery is not the main objective. Several proposed solutions of energy recovery by using hydraulic machines increase the added value of irrigation water networks, which is an open field that needs to be explored in the near future. Full article

(This article belongs to the Special Issue Water Systems towards New Future Challenges)

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9723 KiB

Open AccessArticle

Experimental Study of Air Vessel Behavior for Energy Storage or System Protection in Water Hammer Events

by Mohsen Besharat, Maria Teresa Viseu and Helena M. Ramos

Water 2017, 9(1), 63; https://doi.org/10.3390/w9010063 - 20 Jan 2017

Cited by 27 | Viewed by 7114

Abstract

An experimental assessment of an air pocket (AP), confined in a compressed air vessel (CAV), has been investigated under several different water hammer (WH) events to better define the use of protection devices or compressed air energy storage (CAES) systems. This research focuses [...] Read more.

An experimental assessment of an air pocket (AP), confined in a compressed air vessel (CAV), has been investigated under several different water hammer (WH) events to better define the use of protection devices or compressed air energy storage (CAES) systems. This research focuses on the size of an AP within an air vessel and tries to describe how it affects important parameters of the system, i.e., the pressure in the pipe, stored pressure, flow velocity, displaced volume of water and water level in the CAV. Results present a specific range of air pockets based on a dimensionless parameter extractable for other real systems. Full article

(This article belongs to the Special Issue Water Systems towards New Future Challenges)

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2391 KiB

Open AccessArticle

Energy Saving in a Water Supply Network by Coupling a Pump and a Pump As Turbine (PAT) in a Turbopump

by Armando Carravetta, Lauro Antipodi, Umberto Golia and Oreste Fecarotta

Water 2017, 9(1), 62; https://doi.org/10.3390/w9010062 - 20 Jan 2017

Cited by 33 | Viewed by 5807

Abstract

The management of a water distribution network (WDN) is performed by valve and pump control, to regulate both the pressure and the discharge between certain limits. The energy that is usually merely dissipated by valves can instead be converted and used to partially [...] Read more.

The management of a water distribution network (WDN) is performed by valve and pump control, to regulate both the pressure and the discharge between certain limits. The energy that is usually merely dissipated by valves can instead be converted and used to partially supply the pumping stations. Pumps used as turbines (PAT) can be used in order to both reduce pressure and recover energy, with proven economic benefits. The direct coupling of the PAT shaft with the pump shaft in a PAT-pump turbocharger (P&P plant) allows us to transfer energy from the pressure control system to the pumping system without any electrical device. Based on experimental PAT and pump performance curves, P&P equations are given and P&P working conditions are simulated with reference to the operating conditions of a real water supply network. The annual energy saving demonstrates the economic relevance of the P&P plant. Full article

(This article belongs to the Special Issue Water Systems towards New Future Challenges)

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639 KiB

Open AccessArticle

Initial Provincial Water Rights Dynamic Projection Pursuit Allocation Based on the Most Stringent Water Resources Management: A Case Study of Taihu Basin, China

by Min Ge, Feng-Ping Wu and Min You

Water 2017, 9(1), 35; https://doi.org/10.3390/w9010035 - 10 Jan 2017

Cited by 21 | Viewed by 4942

Abstract

Clarification of initial water rights is the basis and prerequisite for a water rights trade-off market and also an effective solution to the problem of water scarcity and water conflicts. According to the new requirements for the most stringent water resources management in [...] Read more.

Clarification of initial water rights is the basis and prerequisite for a water rights trade-off market and also an effective solution to the problem of water scarcity and water conflicts. According to the new requirements for the most stringent water resources management in China, an initial provincial water rights allocation model is proposed. Firstly, based on analysis of multiple principles for initial provincial water rights allocation including total water use, water use efficiency, water quality of water function zones, regional coordination and sharing, an index system of initial provincial water rights allocation is designed. Secondly, according to dynamic projection pursuit technique, an initial provincial water rights allocation model with the total water use control is set up. Moreover, the self-adaptive chaotic optimization algorithm is applied to tackle the model. Finally, a case study of Taihu Basin is adopted. Considering the multiple scenarios of three different water frequencies (50%, 75% and 90%) and planning year 2030, the empirical results show Jiangsu Province always obtains the most initial water rights. When the developing situation of provinces are given more consideration, Shanghai should acquire more initial water rights than Zhejiang Province; but when the dynamic increment evolving trend of provinces is taken more into account, Shanghai should obtain less initial water rights than Zhejiang Province. The case about Taihu Lake further verifies the feasibility and effectiveness of the proposed model and provides a multiple-scenarios decision making support for entitling the initial water rights with the most stringent water resources management constrains in Taihu Basin. Full article

(This article belongs to the Special Issue Water Systems towards New Future Challenges)

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5261 KiB

Open AccessArticle

Flood Reduction in Urban Drainage Systems: Cooperative Operation of Centralized and Decentralized Reservoirs

by Eui Hoon Lee, Yong Sik Lee, Jin Gul Joo, Donghwi Jung and Joong Hoon Kim

Water 2016, 8(10), 469; https://doi.org/10.3390/w8100469 - 22 Oct 2016

Cited by 28 | Viewed by 13003

Abstract

Failure of drainage systems leads to urban flooding; therefore, structural measures such as the installation of additional drainage facilities, including pump stations and detention reservoirs, have been adopted in the past to prevent and mitigate urban flooding. These measures, however, are costly and [...] Read more.

Failure of drainage systems leads to urban flooding; therefore, structural measures such as the installation of additional drainage facilities, including pump stations and detention reservoirs, have been adopted in the past to prevent and mitigate urban flooding. These measures, however, are costly and time consuming. To maximize flood mitigation efficiency, it is essential to also implement non-structural measures such as effective operation of drainage facilities. In this study, we propose a new cooperative operation scheme for urban drainage systems that involves linking centralized reservoir (CR) and decentralized reservoir (DR) operations by sharing water level information at monitoring nodes. Additionally, we develop a resilience index to assess the system's ability to mitigate, restore, and recover from inundation (i.e., failure). Most results show that flood reduction and resilience in cooperative operations are better than the current operation. However, the results of CR operation for 2010 are worse than the current operation at high monitoring node levels (1.4 m–1.5 m), and the results of DR operation for 2011 are worse than the current operation at low monitoring node levels (0.8 m–0.9 m). All results related to flood reduction and resilience in cooperative operation are superior to the current operation. Full article

(This article belongs to the Special Issue Water Systems towards New Future Challenges)

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3585 KiB

Open AccessArticle

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

by Irene Samora, Pedro Manso, Mário J. Franca, Anton J. Schleiss and Helena M. Ramos

Water 2016, 8(8), 344; https://doi.org/10.3390/w8080344 - 12 Aug 2016

Cited by 68 | Viewed by 9200

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Water Systems towards New Future Challenges)

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1976 KiB

Open AccessArticle

Creation of an SWMM Toolkit for Its Application in Urban Drainage Networks Optimization

by F. Javier Martínez-Solano, Pedro L. Iglesias-Rey, Juan G. Saldarriaga and Daniel Vallejo

Water 2016, 8(6), 259; https://doi.org/10.3390/w8060259 - 18 Jun 2016

Cited by 20 | Viewed by 8955

Abstract

The Storm Water Management Model (SWMM) is a dynamic simulation engine of flow in sewer systems developed by the USEPA. It has been successfully used for analyzing and designing both storm water and waste water systems. However, despite including some interfacing functions, these [...] Read more.

The Storm Water Management Model (SWMM) is a dynamic simulation engine of flow in sewer systems developed by the USEPA. It has been successfully used for analyzing and designing both storm water and waste water systems. However, despite including some interfacing functions, these functions are insufficient for certain simulations. This paper describes some new functions that have been added to the existing ones to form a library of functions (Toolkit). The Toolkit presented here will allow the direct modification of network data during simulation without the need to access the input file. To support the use of this library, a testing protocol was performed in order to evaluate both calculation time and accuracy of results. Finally, a case study is presented. In this application, this library will be used for the design of a sewerage network by using a genetic algorithm based on successive iterations. Full article

(This article belongs to the Special Issue Water Systems towards New Future Challenges)

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2190 KiB

Open AccessArticle

Design Criteria for Suspended Pipelines Based on Structural Analysis

by Mariana Simão, Jesus Mora-Rodriguez and Helena M. Ramos

Water 2016, 8(6), 256; https://doi.org/10.3390/w8060256 - 17 Jun 2016

Cited by 5 | Viewed by 8568

Abstract

Mathematical models have become the target of numerous attempts to obtain results that can be extrapolated to the study of hydraulic pressure infrastructures associated with different engineering requests. Simulation analysis based on finite element method (FEM) models are used to determine the vulnerability [...] Read more.

Mathematical models have become the target of numerous attempts to obtain results that can be extrapolated to the study of hydraulic pressure infrastructures associated with different engineering requests. Simulation analysis based on finite element method (FEM) models are used to determine the vulnerability of hydraulic systems under different types of actions (e.g., natural events and pressure variation). As part of the numerical simulation of a suspended pipeline, the adequacy of existing supports to sustain the pressure loads is verified. With a certain value of load application, the pipeline is forced to sway sideways, possibly lifting up off its deadweight supports. Thus, identifying the frequency, consequences and predictability of accidental events is of extreme importance. This study focuses on the stability of vertical supports associated with extreme transient loads and how a pipeline design can be improved using FEM simulations, in the design stage, to avoid accidents. Distribution of bending moments, axial forces, displacements and deformations along the pipeline and supports are studied for a set of important parametric variations. A good representation of the pipeline displacements is obtained using FEM. Full article

(This article belongs to the Special Issue Water Systems towards New Future Challenges)

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7779 KiB

Open AccessArticle

Modeling Irrigation Networks for the Quantification of Potential Energy Recovering: A Case Study

by Modesto Pérez-Sánchez, Francisco Javier Sánchez-Romero, Helena M. Ramos and P. Amparo López-Jiménez

Water 2016, 8(6), 234; https://doi.org/10.3390/w8060234 - 01 Jun 2016

Cited by 49 | Viewed by 6703

Abstract

Water irrigation systems are required to provide adequate pressure levels in any sort of network. Quite frequently, this requirement is achieved by using pressure reducing valves (PRVs). Nevertheless, the possibility of using hydraulic machines to recover energy instead of PRVs could reduce the [...] Read more.

Water irrigation systems are required to provide adequate pressure levels in any sort of network. Quite frequently, this requirement is achieved by using pressure reducing valves (PRVs). Nevertheless, the possibility of using hydraulic machines to recover energy instead of PRVs could reduce the energy footprint of the whole system. In this research, a new methodology is proposed to help water managers quantify the potential energy recovering of an irrigation water network with adequate conditions of topographies distribution. EPANET has been used to create a model based on probabilities of irrigation and flow distribution in real networks. Knowledge of the flows and pressures in the network is necessary to perform an analysis of economic viability. Using the proposed methodology, a case study has been analyzed in a typical Mediterranean region and the potential available energy has been estimated. The study quantifies the theoretical energy recoverable if hydraulic machines were installed in the network. Particularly, the maximum energy potentially recovered in the system has been estimated up to 188.23 MWh/year) with a potential saving of non-renewable energy resources (coal and gas) of CO₂ 137.4 t/year. Full article

(This article belongs to the Special Issue Water Systems towards New Future Challenges)

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3589 KiB

Open AccessArticle

Optimal Node Grouping for Water Distribution System Demand Estimation

by Donghwi Jung, Young Hwan Choi and Joong Hoon Kim

Water 2016, 8(4), 160; https://doi.org/10.3390/w8040160 - 20 Apr 2016

Cited by 17 | Viewed by 9482

Abstract

Real-time state estimation is defined as the process of calculating the state variable of interest in real time not being directly measured. In a water distribution system (WDS), nodal demands are often considered as the state variable (i.e., unknown variable) and [...] Read more.

Real-time state estimation is defined as the process of calculating the state variable of interest in real time not being directly measured. In a water distribution system (WDS), nodal demands are often considered as the state variable (i.e., unknown variable) and can be estimated using nodal pressures and pipe flow rates measured at sensors installed throughout the system. Nodes are often grouped for aggregation to decrease the number of unknowns (demands) in the WDS demand estimation problem. This study proposes an optimal node grouping model to maximize the real-time WDS demand estimation accuracy. This Kalman filter-based demand estimation method is linked with a genetic algorithm for node group optimization. The modified Austin network demand is estimated to demonstrate the proposed model. True demands and field measurements are synthetically generated using a hydraulic model of the study network. Accordingly, the optimal node groups identified by the proposed model reduce the total root-mean-square error of the estimated node group demand by 24% compared to that determined by engineering knowledge. Based on the results, more pipe flow sensors should be installed to measure small flows and to further enhance the demand estimation accuracy. Full article

(This article belongs to the Special Issue Water Systems towards New Future Challenges)

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4760 KiB

Open AccessArticle

Network Capacity Assessment and Increase in Systems with Intermittent Water Supply

by Amilkar E. Ilaya-Ayza, Enrique Campbell, Rafael Pérez-García and Joaquín Izquierdo

Water 2016, 8(4), 126; https://doi.org/10.3390/w8040126 - 31 Mar 2016

Cited by 17 | Viewed by 8078

Abstract

Water supply systems have been facing many challenges in recent decades due to the potential effects of climate change and rapid population growth. Water systems need to expand because of demographic growth. Therefore, evaluating and increasing system capacity is crucial. Specifically, we analyze [...] Read more.

Water supply systems have been facing many challenges in recent decades due to the potential effects of climate change and rapid population growth. Water systems need to expand because of demographic growth. Therefore, evaluating and increasing system capacity is crucial. Specifically, we analyze network capacity as one of the main features of a system. When the network capacity starts to decrease, there is a risk that continuous supply will become intermittent. This paper discusses how network expansion carried out throughout the network life span typically reduces network capacity, thus transforming a system originally designed to work with continuous supply into a system with intermittent supply. A method is proposed to expand the network capacity in an environment of economic scarcity through a greedy algorithm that enables the definition of a schedule for pipe modification stages, and thus efficiently expands the network capacity. This method is, at the same time, an important step in the process of changing a water system from intermittent back to continuous supply—an achievement that remains one of the main challenges related to water and health in developing countries. Full article

(This article belongs to the Special Issue Water Systems towards New Future Challenges)

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2684 KiB

Open AccessArticle

Seismic-Reliability-Based Optimal Layout of a Water Distribution Network

by Do Guen Yoo, Donghwi Jung, Doosun Kang and Joong Hoon Kim

Water 2016, 8(2), 50; https://doi.org/10.3390/w8020050 - 03 Feb 2016

Cited by 16 | Viewed by 6453

Abstract

We proposed an economic, cost-constrained optimal design of a water distribution system (WDS) that maximizes seismic reliability while satisfying pressure constraints. The model quantifies the seismic reliability of a WDS through a series of procedures: stochastic earthquake generation, seismic intensity attenuation, determination of [...] Read more.

We proposed an economic, cost-constrained optimal design of a water distribution system (WDS) that maximizes seismic reliability while satisfying pressure constraints. The model quantifies the seismic reliability of a WDS through a series of procedures: stochastic earthquake generation, seismic intensity attenuation, determination of the pipe failure status (normal, leakage, and breakage), pipe failure modeling in hydraulic simulation, and negative pressure treatment. The network’s seismic reliability is defined as the ratio of the available quantity of water to the required water demand under stochastic earthquakes. The proposed model allows no pipe option in decisions, making it possible to identify seismic-reliability-based optimal layout for a WDS. The model takes into account the physical impact of earthquake events on the WDS, which ultimately affects the network’s boundary conditions (e.g., failure level of pipes). A well-known benchmark network, the Anytown network, is used to demonstrate the proposed model. The network’s optimal topology and pipe layouts are determined from a series of optimizations. The results show that installing large redundant pipes degrades the system’s seismic reliability because the pipes will cause a large rupture opening under failure. Our model is a useful tool to find the optimal pipe layout that maximizes system reliability under earthquakes. Full article

(This article belongs to the Special Issue Water Systems towards New Future Challenges)

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