scholarly journals Hydropower Generation Through Pump as Turbine: Experimental Study and Potential Application to Small-Scale WDN

Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 958 ◽  
Author(s):  
Matteo Postacchini ◽  
Giovanna Darvini ◽  
Fiorenza Finizio ◽  
Leonardo Pelagalli ◽  
Luciano Soldini ◽  
...  
Keyword(s):  
Real World ◽  
Water Demand ◽  
Rotational Speed ◽  
Water Distribution ◽  
Hydrodynamic Pressure ◽  
Electrical Energy ◽  
Distribution Networks ◽  
Small Scale ◽  
Hydropower Generation ◽  
Reverse Mode

Pump-As-Turbine (PAT) technology is a smart solution to produce energy in a sustainable way at small scale, e.g., through its exploitation in classical Water Distribution Networks (WDNs). PAT application may actually represent a suitable solution to obtain both pressure regulation and electrical energy production. This technology enables one to significantly reduce both design and maintenance costs if compared to traditional turbine applications. In this work, the potential hydropower generation was evaluated through laboratory tests focused on the characterization of a pump working in reverse mode, i.e., as a PAT. Both hydrodynamic (pressure and discharge) and mechanical (rotational speed and torque) conditions were varied during the tests, with the aim to identify the most efficient PAT configurations and provide useful hints for possible real-world applications. The experimental findings confirm the good performances of the PAT system, especially when rotational speed and water demand are, respectively, larger than 850 rpm and 8 L/s, thus leading to efficiencies greater than 50%. Such findings were applied to a small municipality, where daily distribution of pressure and discharge were recorded upstream of the local WDN, where a Pressure Reducing Valve (PRV) is installed. Under the hypothesis of PRV replacement with the tested PAT, three different scenarios were studied, based on the mean recorded water demand and each characterized by specific values of PAT rotational speed. The best performances were observed for the largest tested speeds (1050 and 1250 rpm), which lead to pressure drops smaller than those actually due to the PRV, thus guaranteeing the minimum pressure for users, but also to mechanical powers smaller than 100 W. When a larger mean water demand is assumed, much better performances are reached, especially for large speeds (1250 rpm) that lead to mechanical powers larger than 1 kW combined to head drops a bit larger than those observed using the PRV. A suitable design is thus fundamental for the real-world PAT application.

scholarly journals Optimal Selection of Pumps As Turbines in Water Distribution Networks

Proceedings ◽  
2018 ◽  
Vol 2 (11) ◽  
pp. 685
Author(s):  
Francesco Pugliese ◽  
Francesco De Paola ◽  
Nicola Fontana ◽  
Gustavo Marini ◽  
Maurizio Giugni
Keyword(s):  
Rotational Speed ◽  
Water Distribution ◽  
Distribution Networks ◽  
Operating Conditions ◽  
Water Distribution Networks ◽  
Small Scale ◽  
Optimal Selection ◽  
Pressure Regulation ◽  
Hydropower Generation ◽  
Selection Of

Pumps As Turbines (PATs) can be installed in Water Distribution Networks (WDNs) to couple pressure regulation and small-scale hydropower generation. The selection of PATs in WDNs needs proper knowledge about both the performances of machines available in the market and the operating conditions of the network. In this paper, a procedure for the preliminary selection of a PAT is proposed, based on the design of the main parameters (the head drop and the produced power at the Best Efficiency Point, the impeller diameter and the rotational speed) to both maximize the producible power and regulate the exceeding pressure.

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 Technical note: Problem specific variators in a genetic algorithm for the optimization of drinking water networks

2018 ◽  
Author(s):  
Karel van Laarhoven ◽  
Ina Vertommen ◽  
Peter van Thienen
Keyword(s):  
Drinking Water ◽  
Real World ◽  
Water Distribution ◽  
Water Distribution Network ◽  
Distribution Networks ◽  
Technical Note ◽  
Practical Implementation ◽  
Utility Level ◽  
Water Utility ◽  
Drinking Water Distribution

Abstract. Genetic algorithms can be a powerful tool for the automated design of optimal drinking water distribution networks. Fast convergence of such algorithms is a crucial factor for successful practical implementation at the drinking water utility level. In this technical note, we therefore investigate the performance of a suite of genetic variators that was tailored to the optimisation of a least-cost network design. Different combinations of the variators are tested in terms of convergence rate and the robustness of the results during optimisation of the real world drinking water distribution network of Sittard, the Netherlands. The variator configurations that reproducibly reach the furthest convergence after 105 function evaluations are reported. In the future these may aid in dealing with the computational challenges of optimizing real world networks.

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 Improving the Performance of Water Distribution Networks Based on the Value Index in the System Dynamics Framework

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2445
Author(s):  
Mohsen Hajibabaei ◽  
Sara Nazif ◽  
Robert Sitzenfrei
Keyword(s):  
System Dynamics ◽  
Water Demand ◽  
Environmental Performance ◽  
Water Distribution ◽  
Distribution Networks ◽  
Water Distribution Networks ◽  
Average Pressure ◽  
Environmental Performance Index ◽  
A Value ◽  
Per Capita

This study proposes an algorithm for the improvement of water distribution networks (WDNs) performance using system dynamics. In the first part, the hydraulic and environmental performance of WDNs is investigated. The hydraulic performance is assessed based on the pressure of nodes and the flow velocity in pipes. Furthermore, using life cycle assessment, an environmental performance index is proposed to examine the environmental impacts of WDNs. Moreover, in order to evaluate the overall performance in regards to the costs, a value index in the system dynamics framework is proposed. Then, based on the developed framework, improvement strategies for a WDN are assessed by applying scenarios according to constraints and requirements of the network. The considered scenarios are as follows: (1) reducing per capita water demand of the WDN; (2) decreasing the average pressure in the WDN; (3) reducing the mean age of the system by its renewing; and (4) a combination of reducing the per capita water demand and average pressure in the WDN. The results indicate that the best solutions for increasing the value index in this network are: (a) to reduce the pressure of the pressure reducing valves (PRV) from 30 to 28 m; (b) to reduce the per capita water demand by the annual rate of 0.5% and 1% and decreasing the pressure of the PRV valves together. Therefore, it is shown how the developed algorithm is a purposeful approach for evaluating and improving the performance of WDNs based on the value index.

scholarly journals Leakage detection in water distribution networks using hybrid feedforward artificial neural networks

2021 ◽  
Author(s):  
Hamideh Fallahi ◽  
Mohammadreza Jalili Ghazizadeh ◽  
Babak Aminnejad ◽  
Jafar Yazdi
Keyword(s):  
Neural Networks ◽  
Artificial Neural Networks ◽  
Water Demand ◽  
Water Distribution ◽  
Distribution Networks ◽  
Simulation Software ◽  
Water Distribution Networks ◽  
Flow Rates ◽  
Artificial Neural ◽  
Matlab Programming

Abstract Water leakage control in water distribution networks (WDNs) is one of the main challenges of water utilities. The present study proposes a new method to locate a leakage in WDNs using feedforward artificial neural networks (ANNs). For this purpose, two ANNs training cases are considered. For case1, the ANNs are trained by average daily water demand, including small to large hypothetical leakages. In case 2, the ANNs are trained by hourly water demand and variable hourly nodal leakages over 24 hours. The training parameters are determined by EPANET2.0 hydraulic simulation software using MATLAB programming language. In both cases, first, ANNs are trained using flow rates of total pipes number. Then, sensitivity analysis is performed by hybrid ANNs for the flow rates of pipes number less than the number of the total pipes. The results of proposed hybrid ANNs indicate that if at least the flow rates of 10% of the total pipes are known (using flowmeters), then the leakage locations in both cases can be determined. Despite the complexity of case 2, because of the variations of demand and leakage over the 24-hour, the proposed method could detect the leakage location with high accuracy.

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.

Use of Centrifugal Pumps Operating as Turbines for Energy Recovery in Water Distribution Networks. Two Case Study

2010 ◽  
Vol 107 ◽  
pp. 87-92 ◽  
Author(s):  
José Pérez García ◽  
Antonio Cortés Marco ◽  
Simón Nevado Santos
Keyword(s):  
Distribution Systems ◽  
Water Distribution ◽  
Water System ◽  
Distribution Networks ◽  
Centrifugal Pumps ◽  
Demand Pattern ◽  
Reverse Mode ◽  
Medium Time ◽  
Hydraulic Turbines

The main pipes in water distribution systems have, in many cases, an excess of static pressure. This excess of pressure is usually dissipated by means of intermediate reservoirs, pressure-reducing valves or any other device that produces the required energy loss with the aim to adjust the pressure level to the demand pattern of the system. This hydraulic energy can be used to directly drive a mechanical system or to generate electric power. In this type of recovery energy systems, the available hydraulic power is lower than 100 kW (micro-hydro). In this range, the utilization of conventional hydraulic turbines is not economically viable in short-medium time. In micro-hydropower applications the use of standard centrifugal pumps operated in reverse mode as hydraulic turbines (PAT) can be competitive. In this work, several prediction methods and algorithms suggested by different authors were analyzed and compared. Two case study, in the water system distribution of Murcia and Elche are also presented.

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