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 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.

Numerical Characterization of the Performance Curve of a Regenerative Pump-as-Turbine

2021 ◽  
Author(s):  
Giulio Cantini ◽  
Simone Salvadori
Keyword(s):  
Helical Structure ◽  
Operating Mode ◽  
Numerical Approach ◽  
Pollutant Emissions ◽  
Small Scale ◽  
Centrifugal Pumps ◽  
Green Technologies ◽  
Small Hydropower ◽  
Hydropower Plants ◽  
Working Region

Abstract Energy companies in the power generation field are continuously searching for green technologies to reduce pollutant emissions. In that context, small hydropower plants represent an attractive solution for distributed electricity generation. Reverse-running centrifugal pumps (also known as "pump-as-turbines", PaT) are increasingly selected in that field. Amongst the existing type of pumps, drag-type regenerative pumps (RP) can perform similarly to radial centrifugal pumps in terms of head and efficiency for low specific speed values. For a fixed rotational speed, RPs with linear blades work as pump or turbine only depending on the flow rate. Such peculiarity makes it particularly intriguing to evaluate RPs working characteristic in the turbine operating mode. In the present paper, the performance of three Regenerative Pump-as-Turbines (RPaT) are analyzed using Computational Fluid Dynamics (CFD). The numerical approach is validated using experimental data for both an RP (in the pump working region) and a regenerative turbine (RT) (in the turbine working region). Finally, the numerical simulation of a small-scale RP allows for characterizing both the pump and the turbine regions. Results shows that for a RPaT it is possible to find a "switch region" where the machine turns from behaving as a pump to behaving as a turbine, the losses not being overcome by the turbine power output. The analysis of the RPaT also shows the inversion of the flow pattern and the constant positioning of the pivot around which the flow creates the typical helical structure that characterizes RPs.

scholarly journals Laboratory Analysis of a Piston-Actuated Pressure Reducing Valve under Low Flow Conditions

Proceedings ◽  
2019 ◽  
Vol 48 (1) ◽  
pp. 26
Author(s):  
Riccardo Zarbo ◽  
Valentina Marsili ◽  
Stefano Alvisi ◽  
Marco Franchini
Keyword(s):  
Laboratory Test ◽  
Flow Rate ◽  
Water Distribution ◽  
Distribution Networks ◽  
Low Flow ◽  
Pressure Management ◽  
Flow Conditions ◽  
Pressure Oscillations ◽  
Test Set ◽  
Pressure Reducing Valve

Pressure reducing valves (PRVs) effectiveness for water distribution networks’ (WDNs’) optimal pressure management is proven, but problems and operational limitations have been highlighted by some recent studies. In this work, the functioning of a piston-actuated pressure reducing valve (PA-PRV), subjected to low flow regimes, is investigated by means of a laboratory test set. The results obtained highlight that the PA-PRV tends not to respect the imposed set-point value, and can present an unstable behaviour, characterised by significant pressure oscillations under some flow-rate conditions.

scholarly journals A Methodology for the Optimization of Flow Rate Injection to Looped Water Distribution Networks through Multiple Pumping Stations

Water ◽  
2016 ◽  
Vol 8 (12) ◽  
pp. 575 ◽  
Author(s):  
Christian León-Celi ◽  
Pedro Iglesias-Rey ◽  
F. Martínez-Solano ◽  
Daniel Mora-Melia
Keyword(s):  
Flow Rate ◽  
Water Distribution ◽  
Distribution Networks ◽  
Water Distribution Networks ◽  
Pumping Stations

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 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 Contributions to the development of a methodology for determining the flow rate

2019 ◽  
Vol 112 ◽  
pp. 02008
Author(s):  
Cristian Purece ◽  
Valeriu Panaitescu ◽  
Irina Alina Chera Anghel
Keyword(s):  
Flow Rate ◽  
Operating Characteristics ◽  
Wireless Data ◽  
In Situ Tests ◽  
Small Hydropower ◽  
Actual Operating ◽  
Wireless Data Transmission ◽  
Hydropower Plants ◽  
Data Transmission System

The implementation of the requirements of the European Parliament Directive 2009/28 / EC requires efficient use of the water supply of a hydropower plants installation in order to obtain a higher amount of electricity by producing the same volume of water. In order to achieve efficient utilization of the energy of the water is necessary framing the operation of hydropower plants in the ranges of head course and the electric power so that the energy conversion is carried out in the optimum efficiency characteristic operation of the system. In order to determine as accurately the actual operating characteristics of a hydro-unit, in situ tests are required to determine the actual operating parameters of the hydro-unit. These parameters, the flow rate is the parameter that requires the most complex methodologies to determine. The paper presents a way of improvement but also a simplification of the methodology for in situ determination of the flow to small hydropower plants by using a mobile frame that has implemented a wireless data transmission system.

scholarly journals Failure monitoring in water distribution networks

2006 ◽  
Vol 53 (4-5) ◽  
pp. 503-511 ◽  
Author(s):  
D. Misiunas ◽  
J. Vítkovský ◽  
G. Olsson ◽  
M. Lambert ◽  
A. Simpson
Keyword(s):  
Flow Rate ◽  
Distribution Systems ◽  
Water Distribution ◽  
Design Procedure ◽  
Distribution Networks ◽  
Water Distribution Networks ◽  
Pressure Monitoring ◽  
Burst Detection ◽  
Inlet Flow Rate ◽  
Failure Monitoring

An algorithm for the burst detection and location in water distribution networks based on the continuous monitoring of the flow rate at the entry point of the network and the pressure at a number of points within the network is presented. The approach is designed for medium to large bursts with opening times in the order of a few minutes and is suitable for networks of relatively small size, such as district metered areas (DMAs). The burst-induced increase in the inlet flow rate is detected using the modified cumulative sum (CUSUM) change detection test. Based on parameters obtained from the CUSUM test, the burst is simulated at a number of burst candidate locations. The calculated changes in pressure at the pressure monitoring points are then compared to the measured values and the location resulting in the best fit is selected as the burst location. The EPANET steady-state hydraulic solver is utilised to simulate the flows and pressures in the network. A sensitivity-based sampling design procedure is introduced to find the optimal positions for pressure monitoring points. The proposed algorithm is tested on a case study example network and shows potential for burst detection and location in real water distribution systems.

scholarly journals Evaluation of the Hydroelectric Potential of the TokounouWaterfall, Kankan Prefecture, Guinea

2021 ◽  
pp. 1-6
Author(s):  
Faya Oulare ◽  
Fodé Cisse ◽  
Ansoumane Sakouvogui ◽  
Amadou Sidibe ◽  
Mamby Keita
Keyword(s):  
Flow Rate ◽  
Rural Areas ◽  
Electrical Energy ◽  
Small Hydropower ◽  
Hydro Power ◽  
Hydropower Plants ◽  
Energy Needs ◽  
Useful Power ◽  
Hydro Power Potential

This study is a continuation of the work of evaluation and valuation of the hydro power potential of Small hydropower plants in Guinea. With a total hydroelectric potential estimated at 6000 MW, Guinea generally suffers from a lack of electrical energy, especially in rural areas where nearly 70% of the populations live and less than 15% of this population is connected to the grid. Electricity of the country, which has the negative consequence of the misuse of wood as a source of energy. Hence the need for this study, which aims to assess the hydroelectric potential of the Tokounou waterfall in Kankan prefecture. The main results obtained relate to : the turbine flow rate, the net head, the useful power, the dimensions of the loading basin, the characteristics of the penstock and the choice of turbine. Proposals for the use of the estimated hydroelectric potential have been made, which could improve the energy needs of the locality.

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.

Sign in / Sign up

Export Citation Format

Share Document