scholarly journals Speed and Pressure Controls of Pumps-as-Turbines Installed in Branch of Water-Distribution Network Subjected to Highly Variable Flow Rates

Energies ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4738 ◽  
Author(s):  
Jacopo Carlo Alberizzi ◽  
Massimiliano Renzi ◽  
Maurizio Righetti ◽  
Giuseppe Roberto Pisaturo ◽  
Mosè Rossi
Keyword(s):  
Flow Rate ◽  
Energy Recovery ◽  
Water Distribution ◽  
Water Pressure ◽  
Water Distribution Network ◽  
Distribution Networks ◽  
Small Scale ◽  
Flow Rates ◽  
Simulink Model ◽  
Operating Strategies

The use of Pumps-as-Turbines (PaTs) to replace hydraulic turbines as energy-recovery units in industrial and civil applications is widening the penetration of hydropower in small-scale plants. PaTs show advantages in terms of installation costs and the availability of solutions. Water Distribution Networks (WDNs) represent a potential application where PaTs can be installed to recover water-pressure energy. In this work, a MATLAB©–Simulink model of a WDN branch located in South-Tyrol (Italy) was developed. The flow rate of the WDN was assessed though a measurement campaign showing high daily variability, which negatively affect PaT performance. To let the machine operate close to the Best Efficiency Point (BEP), four different operating strategies were studied to meet the constraint of a fixed pressure equal to 4 bar downstream the WDN branch, required to supply water to users. A PaT speed control strategy was implemented, granting better exploitation of flow rates even in the presence of high daily fluctuations. Energy recovery was 23% higher than that of the reference thanks to an advanced strategy based on controlling PaT rotational speed when the flow rate is smaller than that of the design, and operating in off-design conditions when flow rate is higher than that of the BEP.

scholarly journals An Inverse Transient-Based Optimization Approach to Fault Examination in Water Distribution Networks

Water ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1154
Author(s):  
Chao-Chih Lin ◽  
Hund-Der Yeh
Keyword(s):  
Water Distribution ◽  
Large Scale ◽  
Water Distribution Network ◽  
Distribution Networks ◽  
Small Scale ◽  
Optimization Approach ◽  
Promising Technique ◽  
Preliminary Screening ◽  
Detection Approach ◽  
Symbiotic Organism Search

This research introduces an inverse transient-based optimization approach to automatically detect potential faults, such as leaks, partial blockages, and distributed deteriorations, within pipelines or a water distribution network (WDN). The optimization approach is named the Pipeline Examination Ordinal Symbiotic Organism Search (PEOS). A modified steady hydraulic model considering the effects of pipe aging within a system is used to determine the steady nodal heads and piping flow rates. After applying a transient excitation, the transient behaviors in the system are analyzed using the method of characteristics (MOC). A preliminary screening mechanism is adopted to sift the initial organisms (solutions) to perform better to reduce most of the unnecessary calculations caused by incorrect solutions within the PEOS framework. Further, a symbiotic organism search (SOS) imitates symbiotic relationship strategies to move organisms toward the current optimal organism and eliminate the worst ones. Two experiments on leak and blockage detection in a single pipeline that have been presented in the literature were used to verify the applicability of the proposed approach. Two hypothetical WDNs, including a small-scale and large-scale system, were considered to validate the efficiency, accuracy, and robustness of the proposed approach. The simulation results indicated that the proposed approach obtained more reliable and efficient optimal results than other algorithms did. We believe the proposed fault detection approach is a promising technique in detecting faults in field applications.

scholarly journals The Influence of Changing Hydropower Potential on Performance Parameters of Pumps in Turbine Mode

Energies ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 2103 ◽  
Author(s):  
Martin Polák
Keyword(s):  
Flow Rate ◽  
Water Distribution ◽  
Distribution Networks ◽  
Small Scale ◽  
Operational Parameters ◽  
Small Hydropower ◽  
Hydropower Plants ◽  
Total Head ◽  
Hydropower Potential ◽  
Water Turbines

Pumps as turbines (PAT) are used as an alternative to water turbines in small hydropower plants. The same devices can also be used for energy recovery in water distribution networks. They can replace pressure reduction valves that often lead to energy loss. However, PATs lack the parts that regulate flow so that when a hydropower potential change occurs, efficiency is reduced, as is economic gain. This article summarizes the influence of changing hydropower potential on PAT efficiency and presents comparisons of experimental results with the commonly used predictive model stemming from the theory of physical similarity, which presumes constant PAT efficiency. Our research indicates that the deviation between the model and the real power output calculation at varying potentials was minimal. Similarly, the affine parabola can be used to determine the relationship between total head and flow rate. Other relationships differ from reality the more the PAT efficiency changes. The flow rate and total head dependence on shaft speed are the main factors when setting the optimum operational parameters at varying hydropower potentials. Therefore, a change in efficiency must be included in predictive calculations to correctly optimize PAT operation. The problem is that a change in efficiency cannot be reliably predicted in advance, especially in the case of small-scale devices. For this reason, further research on the issue of changes in PAT efficiency is necessary.

scholarly journals Small-Scale Hydropower Generation in Water Distribution Networks by Using Pumps as Turbines

Proceedings ◽  
2018 ◽  
Vol 2 (23) ◽  
pp. 1486
Author(s):  
Francesco Pugliese ◽  
Francesco De Paola ◽  
Nicola Fontana ◽  
Gustavo Marini ◽  
Maurizio Giugni
Keyword(s):  
Water Distribution ◽  
Cost Benefit Analysis ◽  
Cost Benefit ◽  
Water Distribution Network ◽  
Distribution Networks ◽  
Water Distribution Networks ◽  
Small Scale ◽  
Hydropower Generation ◽  
Time Step ◽  
Simulated Time

In this work, a procedure for the optimal design of Pumps As Turbines in Water Distribution Networks was applied, aimed at both maximizing the hydropower generation and exploiting the excess pressure. The design of the main characteristic PAT parameters, namely the flow rate and the head drop at Best Efficiency Point, the rotational speed and the impeller’s diameter was assessed, under the hypothesis of applying the Electrical Regulation. The procedure allowed to estimate both the produced power and the exploited head at any simulated time-step, as well as the overall daily energy, in compliance with the hydraulic and technical constraints of the system. The model was tested on a simplified Water Distribution Network and a preliminary Cost-Benefit analysis was performed, showing interesting reliefs against short Payback Period.

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.

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

2015 ◽  
Vol 17 (3) ◽  
pp. 347-360 ◽  
Author(s):  
Mauro De Marchis ◽  
Gabriele Freni
Keyword(s):  
Numerical Model ◽  
Economic Benefit ◽  
Energy Recovery ◽  
Energy Production ◽  
Water Distribution ◽  
Method Of Characteristics ◽  
Water Distribution Network ◽  
Distribution Networks ◽  
Economical Benefit ◽  
Water Volumes

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.

scholarly journals Pump as Turbine for the Energy Recovery in a Water Distribution Network: Two Italian (Apulian) Case Studies

2020 ◽  
Vol 2 (1) ◽  
pp. 1
Author(s):  
Gabriella Balacco ◽  
Mario Binetti ◽  
Tommaso Capurso ◽  
Michele Stefanizzi ◽  
Marco Torresi ◽  
...  
Keyword(s):  
Case Studies ◽  
Energy Recovery ◽  
Water Distribution ◽  
Electric Energy ◽  
Water Distribution Network ◽  
Distribution Networks ◽  
Economic Feasibility ◽  
Energy Yield ◽  
Reverse Mode ◽  
The Right

This paper expands on the results of the technical and economic feasibility analysis of substituting existing pressure reduction valves (PRVs) with pumps used as turbines (PaTs) in two real Italian water distribution networks (WDN), chosen as case studies, aiming at effective energy recovery. Water demand variability makes complex the selection of the right pump to be used as a turbine in a WDN maximizing its annual electric energy yield. Hence, this study describes an effective approach that permits us to identify the most suitable pumps, starting from the definition of the best efficiency points at which they should operate in reverse mode.

Analysis of flushing-path effects in water-distribution networks

2010 ◽  
Vol 10 (5) ◽  
pp. 740-745
Author(s):  
I. H. Hyun ◽  
S. Khishigjargal ◽  
Y. W. Chang ◽  
D. H. Kim ◽  
S. Dockko
Keyword(s):  
Flow Velocity ◽  
Water Distribution ◽  
Water Pressure ◽  
Distribution Network ◽  
Water Distribution Network ◽  
Distribution Networks ◽  
Target Area ◽  
Discharge Flow ◽  
Minimum Flow ◽  
Water Amount

The unidirectional and conventional flushing methods are compared in this study and the water amount and flow velocity at junctions within an EPANET water distribution network are compared. In the unidirectional method, the necessary flow and water pressure for the minimum flow velocity for flushing become greater when pipe diameter exceeds a certain value. Therefore, the maximum length of flushable pipeline decreases. The velocity in a pipeline is not highly dependent on the number of open hydrants; in contrast, the velocity in a pipeline after conventional flushing increases with the number of open hydrants. The hydrant discharge flow is smaller in unidirectional flushing than in conventional flushing. However, the percentage of velocities above 1.0 m/s or 1.5 m/s in a flow is relatively higher in conventional flushing when multiple hydrants are open concurrently. Moreover, preplanning or choice of an exact target area is more necessary for unidirectional flushing than for conventional flushing. In this research, a flushing path that can generate optimum effects with less hydrant discharge flow can be observed when conventional and unidirectional flushing processes are applied to specific components in advance.

scholarly journals Optimizing Water Age and Pressure in Drinking Water Distribution Networks

2020 ◽  
Vol 2 (1) ◽  
pp. 51
Author(s):  
Nikolaos Kourbasis ◽  
Menelaos Patelis ◽  
Stavroula Tsitsifli ◽  
Vasilis Kanakoudis
Keyword(s):  
Water Distribution ◽  
Water Pressure ◽  
Distribution Network ◽  
Water Distribution Network ◽  
Distribution Networks ◽  
Water Distribution Networks ◽  
Operating Pressure ◽  
Water Age ◽  
Water Losses ◽  
Simulation And Optimization

Water distribution networks suffer from high levels of water losses due to leaks and breaks, mainly due to high operating pressure. One of the most well-known methods to reduce water losses is pressure management. However, when the operating pressure in a water distribution network reduces, the time the water stays within the network (called water age) increases. Increased water age means deteriorated water quality. In this paper, water pressure in relation to water age is addressed in a water distribution network in Greece. Using simulation and optimization tools, the optimum solution is found to reduce water age and operating pressure at the same time. In addition, District Metered Areas are formed and water age is optimized.

A study on appropriate investment of pipeline rehabilitation for water distribution network

2005 ◽  
Vol 5 (2) ◽  
pp. 31-38
Author(s):  
A. Asakura ◽  
A. Koizumi ◽  
O. Odanagi ◽  
H. Watanabe ◽  
T. Inakazu
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Water Supply ◽  
Water Distribution ◽  
Ad Hoc ◽  
Distribution Network ◽  
Water Distribution Network ◽  
Distribution Networks ◽  
Optimal Basis ◽  
Model Case

In Japan most of the water distribution networks were constructed during the 1960s to 1970s. Since these pipelines were used for a long period, pipeline rehabilitation is necessary to maintain water supply. Although investment for pipeline rehabilitation has to be planned in terms of cost-effectiveness, no standard method has been established because pipelines were replaced on emergency and ad hoc basis in the past. In this paper, a method to determine the maintenance of the water supply on an optimal basis with a fixed budget for a water distribution network is proposed. Firstly, a method to quantify the benefits of pipeline rehabilitation is examined. Secondly, two models using Integer Programming and Monte Carlo simulation to maximize the benefits of pipeline rehabilitation with limited budget were considered, and they are applied to a model case and a case study. Based on these studies, it is concluded that the Monte Carlo simulation model to calculate the appropriate investment for the pipeline rehabilitation planning is both convenient and practical.

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