Optimal Regulation of Pumping Station in Water Distribution Networks Using Constant and Variable Speed Pumps: A Technical and Economical Comparison (original) (raw)
Related papers
Nowadays, the major expenses in water supply systems (WSSs) are related to energy consumption. Pump stations usually represent the major portion of total energy costs. Generally, in most WSSs, the pump stations operations are only based on the pumps on/off, without taking advantage of variable-speed equipment. The pumps are switched on when the tanks, responsible for supplying certain populations, reach their minimum levels. These pumps are only switched off when the tanks reach their maximum levels. In the cases where variable-speed equipment is used, planned control strategies are almost always missing. The introduction operational pump schedules adapted to the energy prices variation and to the consumption patterns of the populations can optimise pump stations operations, minimising energy costs significantly. However, the process of finding the best pump pattern can present difficulties due to the complexity of some WSSs (multiple pumps, multiple reservoirs, nonlinear behaviour of the systems, etc.). A methodology for variable-speed pumps control is presented in this work. With the aim of test this methodology and apply distinct algorithms for the pumps schedules optimisation, a computational tool was developed. The tool consists on an automatic connection between the hydraulic simulator EPANET 2.0 and the optimisation algorithms, providing, after multiple iterations and evaluations, an optimal pump pattern for a certain water supply network represented. Both gradient-based and meta-heuristic algorithms are used in this study in order to improve the energy efficiency of two distinct examples of network. Results of the hydraulic simulation of the networks with the optimal pump schedules are used to predict the future behaviour of the systems with this type of operation adjustment. Thus, it is possible to verify if the system requirements (such as, minimum pressures, tanks levels, consumers supply, etc.) are being attended. Optimisation results demonstrated that the pump schedules optimisation provides significant reductions on energy costs without compromising the proper operation of the systems.
Assessing variable speed pump efficiency in water distribution systems
Energy savings and greenhouse gas emission reductions are increasingly becoming important design targets in many industrial systems where fossil fuel based electrical energy is heavily utilised. In water distribution systems (WDSs) a significant portion of operational cost is related to pumping. Recent studies have considered variable speed pumps (VSPs) which aim to vary the operating point of the pump to match demand to pumping rate. Depending on the system characteristics, this approach can lead to considerable savings in operational costs. In particular, cost reductions can take advantage of the demand variability and can decrease energy consumption significantly. One of the issues in using variable speed pumping systems, however, is the total efficiency of the electric motor/pump arrangement under a given operating condition. This paper aims to provide a comprehensive discussion about the components of WDS that incorporate variable speed pumps (including electric motors, variable frequency drives and the pumps themselves) to provide an insight of ways of increasing the system efficiency and hence to reduce energy consumption. In addition, specific attention is given to selection of motor types, sizing, duty cycle of pump (ratio of on-time and time period), and losses due to installation and motor faults. All these factors affect the efficiency of motor drive/pump system.
Pump schedule optimisation techniques for water distribution systems
2013
The present volume is the final manuscript of the Ph.D. Thesis of József Gergely Bene (Thesis in the following). The Thesis will be also published in Acta Universitatis Ouluensis, Series C. (ACTA in the following. It is the official publisher of the University of Oulu.) Thus the copyright of this manuscript belongs to ACTA, and this volume is only for review purposes. The style and format already suit the requirements of ACTA. The author also states here that he will not perform any modification in the text or the figures; they remain the same as they are therefore the official review process can be started. However, the layout of some pages (e.g. the front page, abstract) might be changed by ACTA. After printing the Thesis in ACTA, both Universities will receive their own copy.
Energy saving and management of water pumping networks
Heliyon, 2021
The main consumption of energy in water systems is the pumps. Due to the different tariff of energy consumption during the one day, the operation of these pumps should be controlled to minimize their consumption and consequently decrease the cost of operation. This paper utilizes an optimization algorithm to control the on/off operation of water pumps to minimize the cost of energy consumption and number of pump switching of water networks. This objective function is subjected to some optimization and hydraulic constraints such as the tanks upper and lower limits, and water network pressure limit. The proposed methodology is an iterative combination process between an optimization algorithm and EPANet hydraulic simulator where optimization algorithm generates the schedules and the hydraulic simulator is used to check the feasibility of these schedules. The suggested optimization method is the artificial electric field algorithm (AEFA). This methodology is applied to three water networks; EPANet practical example network, Richmond network and a part from Toronto network with a variable energy consumption tariff. The AEFA is tested and trained to select the best values of its controlling parameters for each network. The results show that the energy consumption cost is significantly decreased by the optimal schedules of water pumps. Also AEFA is compared with other optimization algorithms such as the genetic and particle swarm algorithms on the same networks and energy tariff and the results show the superiority of AEFA in the convergence and saving of the cost of energy consumption.
Energy Optimization of the Pumping Station
Environmental Sciences Proceedings
The main challenge in the field of water distribution systems (WDS) is (re)designing the network in order to achieve savings. In many water systems, there are pumping stations designed for much larger flows than what would be observed under normal operating conditions. On the other hand, reducing the diameter of the water pipes has become the main saving method. Designers very often forget to design the network so that it can be used for fire protection purposes. The computer modelling of water networks supports the decision-making process by identifying the optimal compromise between cost and performance (e.g., flow, velocity, pressure). Computer models help in the selection of optimal values of hydraulic pumps, preparation of the pump control method and selection of energy-optimized pumping systems, ensuring the efficiency and pressure of the WDS during normal operation and in fire conditions. The article presents the results of optimization of the pump station in terms of efficie...
Journal of Water Supply: Research and Technology-Aqua
The UN Sustainability Goals address measures to reduce environmental pollution. Water distribution systems (WDSs) use electric energy, which pollutes the atmosphere through, at least partly, the burning of coal. This study simulates, through modeling, variable-speed pumps (VSPs) on 15 different real WDSs on the network solver EPANET and analyzes the payback period. An algorithm is introduced here to select the optimal pump speed pattern to save the most energy while satisfying the constrain of sufficient pressure at all times and all locations. It was found that five of the 15 systems operated unsuccessfully using a VSP, due to the VSP operating at lower speeds causing a lower pressure than normal, thereby causing the pressure to become negative. Additionally, a new chart that compares the payback period, project life, and energy costs between the base case and the VSP case was developed and different regions on the chart reflect different decision criteria.
Revista AIDIS de Ingeniería y Ciencias Ambientales. Investigación, desarrollo y práctica
Electricity costs for pumping account for the majority of operating expenses for water distribution systems. Therefore, researchers and technicians in the water sector have sought to develop techniques that minimize the consumption of electricity in these systems. The large number of elements, which can change state at any time, generates a range of possibilities that makes it difficult to determine which operational scheme is most efficient. Defining the best operating rules for pumping systems is often a complex activity. In this context, the present work presents an optimization model for water distribution systems that combines the efficient use of reservoirs with the best operational rule for activating pumping systems. Using a genetic algorithm, the developed model aims to minimize the operating costs of electrical energy in the systems. The results obtained indicated that, with a better use of the water storage infrastructure, it is possible to reduce the electricity costs of...
Efficient optimization of pump scheduling for reduction of energy costs and Greenhouse gas emissions
Journal of Science and Technology Issue on Information and Communications Technology, 2019
Optimal pump scheduling has been applying to decrease operating costs of water distribution systems (WDSs). However, the operations of pumping stations will result in an increase of Greenhouse gas emission (GHG). To reduce GHG, pumping stations should be operated with high efficiency. For this reason, optimal pump cheduling should take into account both energy cost savings and pumping station efficiency. The aim of this article is to suggest an efficient multi-objective optimization solution or minimizing pumping energy cost and maximizing pumping station efficiency. As a result, a trade-off solution compromising pumping energy cost and pumping system efficiency will be achieved. The Genetic Algorithm (GA) combined with a WDS simulator, EPANET will be applied to solve the pump scheduling problem in one benchmark WDS and the results from our solution will be compared to the ones in the literature in terms of pumping energy cost and efficiency.
Energy Optimization Using a Pump Scheduling Tool in Water Distribution Systems
ARO-THE SCIENTIFIC JOURNAL OF KOYA UNIVERSITY, 2020
Water distribution management system is a costly practice and with the growth of population, the needs for creating more cost-effective solutions are vital. This paper presents a tool for optimization of pump operation in water systems. The pump scheduling tool (PST) is a fully dynamic tool that can handle four different types of fixed speed pump schedule representations (on and off, time control, time-length control, and simple control [water levels in tanks]). The PST has been developed using Visual Basic programming language and has a linkage between the EPANET hydraulic solver with the GANetXL optimization algorithm. It has a user-friendly interface which allows the simulation of water systems based on (1) a hydraulic model (EPANET) input file, (2) an interactive interface which can be modified by the user, and (3) a pump operation schedule generated by the optimization algorithm. It also has the interface of dynamic results which automatically visualizes generated solutions. The capabilities of the PST have been demonstrated by application to two real case studies, Anytown water distribution system (WDS) and Richmond WDS as a real one in the United Kingdom. The results show that PST is able to generate high-quality practical solutions.
COMPARISON OF METHODS OF PUMP SCHEDULING IN WATER SUPPLY SYSTEMS
2001
In the domestic water supply industry, the reduction of pumping costs is a continuing objective. With the efficient scheduling of pumping operations, it is considered that 10% of the annual expenditure on energy and related costs may be saved. A typical cost function will include all of the expenditure caused by the pumping process and also consider the electrical cost of pumping taking into account the various electrical tariffs, as well as peak demand and pump switching costs. Using only fixed speed pumps, it is possible to use an efficient dynamic programming based method, provided that the storage reservoir levels are known. Other techniques that are showing fruitful results in optimisation are genetic programming and simulated annealing. This paper compares these methods and discusses which is more appropriate in this type of pump scheduling problem.