Pumping Energy Costs Research Articles

Experimental Study on the Effect of Skin Friction Drag and Convective Heat Transfer for Viscoelastic and Pseudoplastic Fluid Flow

Drag Reducing Agents (DRAs) have a huge impact and major concern in engineering and industrial applications. It makes the fluid flow turbulent to laminar, dampens eddy reduces head loss by up to a certain limit, and saves pumping energy costs. Viscosity is the property that dampens eddy due to the viscous effect, which increases the fluidity up to a certain limit. Pseudoplasticity is the shear thinning effect that decreases viscosity when the flow rate increases. So, for the viscoelastic effect, we can increase the concentration up to a certain limit to reduce head loss. Still, during flow due to the pseudoplastic effect, the viscosity will start decreasing which is a negative effect. So, these combined effects are studied to reduce skin friction drag in the pipeline and save energy costs which will be convenient for the food industry, chemical, and medicine industries. In this investigation, investigation is carried out for 0.3 g/L, 0.2 g/L, and 0.15 g/L of xanthan gum in turbulent flow to observe the pressure drop and heat transfer rate. The study reveals that after increasing viscosity the pressure drop reduced significantly. Conversely, the heat transfer rate was also reduced due to the poor mixing effect. A higher performance and less vibration of the pump was also observed. It was concluded that the frictional pressure drop was reduced up to 85 % and the heat transfer rate was reduced by up to 90% by increasing the concentration of the DRA up to 0.3 g/L at 10 LPM than the pure water or base fluid as a working substance on the double pipe heat exchanger. As the heat transfer rate reduced up to 90% with reducing pressure drop another aim of the study was to establish a concentration and flowrate for which the heat transfer rate is maximum and it was found at a concentration of 0.15 g/L of DRAs (drag reducing agents) at 22 LPM (maximum flowrate at this setup).

Representing Hourly Energy Prices in a Large-Scale Monthly Water System Model

Water system management models represent different purposes, such as water supply, flood control, recreation, and hydropower. When building large-scale system models to represent these diverse objectives, their most appropriate time steps for each purpose often do not coincide. A monthly time step is usually sufficient for water supply modeling, but it can be too coarse for flood control, hydropower, and energy operations, where hourly time steps are preferred. Large-scale water management and planning models mostly employ monthly time steps, but using monthly average energy prices underestimates hydropower revenue and overestimates pumping energy cost because these plants tend to operate during times with above- or below-average energy prices within any month. The approach developed here uses hourly varying prices depending on the percent of monthly operating hours. This paper examines an approach that approximately incorporates hourly energy price variations for hydropower and pumping into large-scale monthly time-step water system model operations without affecting water delivery results. Results from including hourly varying energy prices in a large-scale monthly water supply model of California (CALVIN) are presented. CALVIN is a hydroeconomic linear programming optimization model that allocates water to agricultural and urban users with an objective to minimize total scarcity costs, operating costs, and hydropower revenue loss. Thirteen hydropower plants are modeled with hourly varying prices, and their revenue increased by 25 to 58% compared to revenue calculated with monthly average constant energy prices. Hydropower revenue improvements are greater in critically dry years. For pumping plants modeled with hourly varying prices, the energy use cost decreased by 10 to 59%. This study improves system representation and results for large-scale modeling.

A new static mixer concept for enhanced desalination performance in flow-electrode capacitive deionization (FCDI) systems

Poor electrical conductivity and high pumping energy cost are two major challenges that limit the desalination performance of flow-electrode capacitive deionization (FCDI) systems. In this study, we address these limitations by utilizing low carbon loading suspensions (≤2 wt%) with water-like viscosity in a novel static mixer design, referred to as a membrane-assisted static mixer (MASM). MASMs improved the electrical conductivity of the slurry by minimizing the charge transport distances between the active material and current collector as the ion-exchange membrane was compressed directly against the current collector surface (i.e., zero-gap flow field). Continuous mixing of the active material was achieved by controlling the displacement of the membrane via pressure fluctuations from the peristaltic pumps. A parametric study of three MASM flow field geometries was performed at varying flow rates of 1, 3, 5, 10, 15 and 25 mL min−1 and 0.5, 1, and 2 wt% activated carbon (AC). The best-performing flow configuration (2 wt% AC and 15 mL min−1) showed a high salt removal rate of 4.424 μg NaCl cm−2 s−1 with a total energy consumption of 98.95 kJ mol−1.

Water-energy-food-environment nexus in action: Global review of precepts and practice

Abstract Using water-energy-food-environment (WEFE) nexus as the prism, this review explores evolution of groundwater governance in Iran, Saudi Arabia, Mexico, China, Bangladesh and India – which together account for two-thirds of the global groundwater-irrigated area. Global discourse has blamed widespread water scarcity squarely on supply-side policymaking and advocated a broader template of water governance instruments. Integrated Water Resources Management (IWRM) presented just such a template – with pricing, participation, rights and entitlements, laws, regulations, and river basin organizations – as additional water governance tools. However, the IWRM template faced disillusionment and pushback in many emerging economies. WEFE nexus, the new paradigm, prioritizes system-level optima over sectoral maxima by harnessing synergies and optimizing trade-offs between food, water, energy, soil, and eco-system sustainability within planetary boundaries. Realizing this vision presents a complex challenge in groundwater governance. Global groundwater economy comprises three sub-economies: (a) diesel-powered unregulated, as in Nepal terai, eastern India, Bangladesh, Pakistan Punjab and Sind, and much of Sub-Saharan Africa, where use-specific energy subsidies are impractical; (b) electricity-powered regulated, as in North America and Europe, where tubewells are authorized, metered and subject to consumption-linked energy charges; and (c) electricity-powered unregulated, as in geographies covered by our review – barring China, Bengal and Bangladesh – where unmeasured electricity subsidies have created a bloated groundwater economy. This last sub-economy represents the heartland of global groundwater malgovernance, least equipped to meet the sustainability challenge. It has an estimated 300 million horsepower of grid-connected electric pumps that are either unauthorized and/or unmetered and/or use free or heavily subsidized or pilfered power for irrigating 50–52 million hectares, nearly half of global groundwater-irrigated area. In (a) and (b), groundwater scarcity inspires water-energy saving behavior via increased energy cost of pumping. In sub-economy (c), users are immune to energy costs and impervious to groundwater depletion. Here, the WEFE nexus has remained blind to the irrigation realpolitik that catalyzes or constrains policy action. We explore why the political costs of rationalizing subsidies are prohibitive and exemplify how a smart transition from fossil to solar energy for pumping may offer an opportunity to turn the perverse WEFE nexus into a virtuous one.

Plasma facing components with capillary porous system and liquid metal coolant flow

Liquid metal can create a renewable protective surface on plasma facing components (PFC), with an additional advantage of deuterium pumping and the prospect of tritium extraction if liquid lithium (LL) is used and maintained below 450 °C, the temperature above which LL vapor pressure begins to contaminate the plasma. LM can also be utilized as an efficient coolant, driven by the Lorentz force created with the help of the magnetic field in fusion devices. Capillary porous systems can serve as a conduit of LM and simultaneously provide stabilization of the LM flow, protecting against spills into the plasma. Recently, a combination of a fast-flowing LM cooling system with a porous plasma facing wall (CPSF) was investigated [A. Khodak and R. Maingi, Nucl. Mater. Energy 26, 100935 (2021)]. The system takes an advantage of a magnetohydrodynamics velocity profile as well as attractive LM properties to promote efficient heat transfer from the plasma to the LL at low pumping energy cost, relative to the incident heat flux on the PFC. In the case of a disruption leading to excessive heat flux from the plasma to the LM PFCs, LL evaporation can stabilize the PFC surface temperature, due to high evaporation heat and apparent vapor shielding. The proposed CPSF was optimized analytically for the conditions of a fusion nuclear science facility [Kessel et al., Fusion Sci. Technol. 75, 886 (2019)]: 10 T toroidal field and 10 MW/m2 peak incident heat flux. Computational fluid dynamics analysis confirmed that a CPSF system with 2.5 mm square channels can pump enough LL so that no additional coolant is needed.

Staged energy and water quality optimization for large water distribution systems.

Simultaneous optimization of energy and water quality in real-time large-sized water distribution systems is a daunting task for water suppliers. The complexity of energy optimization increases with a large number of pipes, scheduling of several pumps, and adjustments of tanks' water levels. Most of the simultaneous energy and water quality optimization approaches evaluate small (or hypothetical) networks or compromise water quality. In the proposed staged approach, Stage 1 uses a risk-based approach to optimally locate the chlorine boosters in a large distribution system based on residual chlorine failures and the associated consequences in different land uses of the service area. Integrating EPANET and CPLEX software, Stage 2 uses mixed integer goal programming for optimizing the day-ahead pump scheduling. The objective function minimizes the pumping energy cost as well as the undesirable deviations from goal constraints, such as expected water demand. Stage 3 evaluates the combined hydraulics and water quality performances at the network level. The implementation of the proposed approach on a real-time large-sized network of Al-Khobar City in Saudi Arabia, with 44 groundwater wells, 12 reservoirs, 2 storage tanks, 191 mains, 141 junctions, and 17 pumps, illustrated the practicality of the framework. Simulating the network with an optimal pumping schedule and chlorine boosters' locations shows a 40% improvement in water quality performance, desired hydraulics performance with optimal pump scheduling, and an average 20% energy cost reduction compared to the normal (unoptimized) base case scenario.

Improved Pump Setpoint Selection Using a Calibrated Hydraulic Model of a High-Pressure Irrigation System

This paper presents a case study of the operational management of the Robinvale high-pressure piped irrigation water delivery system (RVHPS) in Australia. Based on datasets available, improved pump setpoint selection using a calibrated hydraulic model is investigated. The first step was to implement pre-processing of measured flow and pressure data to identify errors in the data and possible faulty sensors. An EPANET hydraulic simulation model was updated with calibrated pipe roughness height values by using the processed pressure and flow data. Then, new pump setpoints were selected using the calibrated model given the actual measured demands such that the pressures in the network were minimized subject to required customer service standards. Based on a two-day simulation, it was estimated that 4.7% savings in pumping energy cost as well as 4.7% reduction in greenhouse gas emissions can be achieved by applying the new pump setpoints.

Design and optimization of electrodialysis process parameters for brackish water treatment

Effect of flow velocity and cell-pair thickness in electrodialysis (ED) is studied. The production cost includes pump energy, while the size of the system is considered as an output variable. The performance of ED system depends on three categories of process parameters namely water quality data, stack configuration and flow characteristic inside the stack. The design of ED system is complex due to interrelation among the system variables so the design calculation chronology steps are developed with flow-chart for the fix feed salinity of groundwater and salt removal rate. The effect of recovery ratio on capital and energy cost is studied and found unidirectional. Sparingly soluble salt present in feed decides the upper limit and obtained 70–75% recovery rate based on the feedwater quality. The optimum value of the linear flow velocity and cell-pair thickness can be obtained by the trade-off among capital cost, stack energy cost and pumping energy cost. Simultaneous effect of both the variable on minimizing the total cost gives the narrow working range of flow velocity 15–17 cm/s and 0.4–0.8 mm thickness. The minimum production cost of 0.08 USD/m3 is obtained at 16 cm/s velocity and 0.5 mm thickness.

An iterative algorithm for groundwater pumping energy cost minimization

This article presents an algorithm for solving a very common water resources management problem. This involves finding the optimal solution to the problem of minimizing the cost of energy consumed during pumping and transporting water from a group of wells to a reservoir to satisfy the water needs of a residential area. This algorithm addresses the problem of minimizing the cost of the energy consumed by pumping groundwater through an iterative process. The results of the algorithm are verified by solving the same problem with the generalized reduced gradient algorithm, which is integrated into the Microsoft Excel Solver add-in. It is found that the algorithm accurately calculates the optimal solution of the problem, while the results of the solutions of similar mathematical programming problems with this algorithm can be used as guides for other more complicated problems.

Global Internal Recirculation Alternative Operation to Reduce Nitrogen and Ammonia Limit Violations and Pumping Energy Costs in Wastewater Treatment Plants

The internal recirculation plays an important role in different areas of the biological treatment of wastewater treatment plants because it has a great influence on the concentration of pollutants, especially nutrients. A usual manipulation of the internal recirculation flow rate is based on the target of controlling the nitrate concentration in the last anoxic tank. This work proposes an alternative for the manipulation of the internal recirculation flow rate instead of nitrate control, with the objective of avoiding limit violations of nitrogen and ammonia concentrations and reducing operational costs. A fuzzy controller is proposed to achieve it based on the effects of the internal recirculation flow rate in different areas of the biological treatment. The proposed manipulation of the internal recirculation flow rate is compared to the application of the usual nitrate control in an already established and published operation strategy by using the internationally known benchmark simulation model no. 2 as a working scenario. The results show improvements with reductions of 59.40% in ammonia limit violations, 2.35% in total nitrogen limit violations, and 38% in pumping energy costs.

Intensification of mixing-pumping process in a novel active micropump-mixer with maximum efficiency and minimum energy cost: A LBM-RSM approach

In the present paper, a double multiple-relaxation-time lattice Boltzmann simulation and response surface optimization are performed to optimize the performance of a novel active micropump-mixer at high-Peclet number flows. The micropump-mixer is comprised of rotationally oscillating rectangular stirrer and two identical square rotors. Effects of three important non-dimensional parameters of the stirrer, including its diameter (DS), maximum velocity (US), and amplitude (K) are investigated on the mean mixing efficiency (εout), time-averaged of the instantaneous dimensionless averaged velocity (Uave), mixing energy cost (mec) and pumping energy cost (pec). All calculations are carried out for the non-dimensional US and K in the range of 0.1-1, and for DS in the range of 0.5−0.9, at fixed Reynolds and Peclet numbers of Re=1 and Pe=10000. Results indicated that εout increases with DS, and especially with K, while it displays a non-monotonic behavior with US. Furthermore, Uave and mec decrease with increasing DS and K. However, Uave is not influenced by US variations, but mec shows a decrease-increase trend with increasing US. The pec increases with increasing of all three parameters. Finally, optimization results indicated that non-dimensional values of 0.5, 0.702 and 1 respectively for Ds, Us and K are optimum values for multiple-response optimization.

Minimizing Pumping Energy Cost in Real-Time Operations of Water Distribution Systems Using Economic Model Predictive Control

Optimizing pump operations is a challenging task for real-time management of water distribution systems (WDSs). With suitable pump scheduling, pumping costs can be significantly reduced. In this research, a novel economic model predictive control (EMPC) framework for real-time management of WDSs is proposed. Optimal pump operations are selected based on predicted system behavior over a receding time horizon with the aim to minimize the total pumping energy cost. Time-varying electricity tariffs are considered while all the required water demands are satisfied. The novelty of this framework is to choose the number of pumps to operate in each pump station as decision variables in order to optimize the total pumping energy costs. By using integer programming, the proposed EMPC is applied to a benchmark case study, the Richmond Pruned network. The simulation with an EPANET hydraulic simulator is implemented. Moreover, a comparison of the results obtained using the proposed EMPC with those obtained using trigger-level control demonstrates significant economic benefits of the proposed EMPC.

Aplicação de modelos de otimização na operação de sistemas elevatórios em redes de abastecimento de água

<p>Os sistemas de abastecimento de água são fundamentais para a sociedade e estão sendo cada vez mais exigidos em termos de quantidade e qualidade da água. Além desses dois aspectos, que são a base do serviço prestado, outras questões tem gerado muita pressão, a preservação ambiental, a qualidade do serviço das companhias e os custos aos consumidores. A melhoria na prestação do serviço e a redução de custos passam, necessariamente, pelo aperfeiçoamento da operação sistemas. O custo da energia com o bombeamento é um dos fatores que mais afeta o custo operacional dos sistemas. A relevância do custo da energia com o bombeamento motivou a realização deste trabalho. Por meio de modelagem computacional buscou-se minimizar os custos do bombeamento de um sistema real. A programação não linear e os algoritmos genéticos da ferramenta solver do Excel foram aplicadas para se obter o custo ótimo do bombeamento. As variáveis de decisão do modelo foram os intervalos de operação das bombas durante um ciclo de 24 horas. As principais restrições foram respeitar os limites dos reservatórios e a recuperação dos níveis ao final do ciclo de 24 horas. As duas técnicas foram capazes de encontrar soluções viáveis, no entanto, os algoritmos genéticos confirmaram sua lentidão em relação ao Gradiente Reduzido Generalizado (GRG). Em ambas as técnicas, o horário de ponta foi minimamente alocado na operação. Com relação ao sistema estudado constatou-se que o maior responsável pelo custo operacional é a adução da Estação de Tratamento de Água (ETA) ao R5, aproximadamente 81,69%, e existe uma limitação na capacidade de bombeamento que impede o desligamento total das bombas no horário de ponta. No presente trabalho, os seguintes consumos específicos foram obtidos: estação elevatória EE 1 (ETA-R5) 0,897kWh/m³; EE 2 (R5-R4) 0,16 kWh/m³; EE 3 (R4-RLS) 0,617037 kWh/m³ e EE 4 (R4-RC) de 0,471852 kWh/m³. Considerando a média do subsistema estudado tem-se 0,537 kWh/m³, sendo mais eficiente a EE 2 (R5-R4) e a menos eficiente a EE 1(ETA-R5). Isso pode ser justificado pela maior demanda e por ser necessária a operação em horário de ponta com bombas de elevada potência. O investimento na melhoria do sistema é necessário para aumentar sua eficiência energética e, consequentemente, reduzir os elevados custos da operação.</p>

Optimum Process of Pipeline Selection in Water Distribution Network: Case Study

This research deals with a case study of clear water rising pumping main to supply drinking water in Adityapur Municipality, Jharkhand, India. Pipes are important and most cost bearing entity in a water pipeline distribution network. Hence proper selection of pipe is most challenging job to pipeline designers. This study shows about various processes involved in order to get an optimum design in respect to the selection of pipes using WaterGEMS software. A 60 MLD Subarnarekha Water Supply Scheme (WSS) is been considered where two numbers 30 MLD pumps with 40 m rated head have been proposed on the basis of two working and two standby modes to fulfill the demand of drinking water. Mainly cost variation is compared due to change in pipe diameter in relation with energy cost against this WSS. As per the data received, the inputs were incorporated and accordingly the results are interpreted. The whole considered network consists 37 pipes and 10 junctions. Various system outputs are been reflected for steady state simulations. An extended period simulation has also been carried out to compute filling time of all tanks according to their water demands. The pumping energy cost comparison is also reflected when a 1200 mm diameter of pipeline is been replaced with 1000 mm pipeline that runs for 4.173 km. This study is an effort to open up the process of cost optimization in pressure pipeline network for implementation in various water supply schemes.

Application of Clustered-NA-ACO in three-objective optimization of Water Distribution Networks

ABSTRACTOptimal operation of pumping stations in Water Distribution Networks (WDNs) is presented based on three conflicting objectives, including 1) pumping energy costs, 2) hydraulic reliability, and 3) quality reliability. We proposed a three-objective optimization algorithm called Clustered Non-dominated Archiving Ant Colony Optimization (Clustered-NA-ACO) and evaluated the efficiency of this algorithm through DTLZ test functions. Incorporating k-means clustering strategy with NA-ACO can greatly improve the distribution of solutions and reduce the run time compared to NA-ACO. A pressure-driven analysis tool called EPANET-Iterative Modifications to Nodal Outflows (EPANET-IMNO) is developed for dynamic analysis of WDNs and linked directly to Clustered-NA-ACO. We applied this simulation-optimization tool to two WDNs. The results show that it is necessary to consider hydraulic reliability and quality reliability as two separate objective functions in WDNs with storage tanks. We also suggested the combined form of the two reliability indicators in the optimization of WDNs without any storage tanks.

Efficient optimization of pump scheduling for reduction of energy costs and Greenhouse gas emissions

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.

Optimum Reliable Operation of Water Distribution Network Considering Pumping Station and Tank

This research aims to optimize the operation of pumping stations in water distribution networks (WDNs). Two main objectives are considered: minimizing the pumping energy costs through the scheduling of pumping stations by means of variable-speed pumps and, maximizing the reliability of pumping stations or storage tanks. Accordingly, a multi-objective ant colony optimization is developed in Visual Studio C ++. This optimization algorithm is directly linked to EPANET2.0 for two case studies including Anytown and two loops WDNs. This study reveals that there is a strong correlation between the number of nodes and pumps, and the range of the hydraulic reliability in the solutions of pareto-optimal front. In scheduling of pumping station operation, a wider range of reliability can be provided in storage tanks compared to pumping stations. Based on WDN’s requirements, decision makers can choose a solution with the desired reliability of pumping stations and storage tanks and the relevant pumping energy costs.

Iterative Extended Lexicographic Goal Programming Method for Fast and Optimal Pump Scheduling in Water Distribution Networks

AbstractPump scheduling in water distribution networks is important, especially with current high energy prices. A good pump schedule is one that reduces pump energy and maintenance costs without w...

Novel highly dispersible, thermally stable core/shell proppants for geothermal applications

The use of proppants, especially larger and more dense proppants, during reservoir stimulation in tight oil and gas plays requires the introduction of highly viscous fluids to transport the proppants (mm–mm) with the fracturing fluid. The highly viscous fluids required result in increased pump loads and energy costs. Furthermore, although proppant deployment with fracturing fluids is a standard practice for unconventional oil and gas stimulation operations, there are only a few examples in the US of the applying proppant technology to geothermal energy production. This is due to proppant dissolution, proppant flowback, and loss of permeability that, although also occurs during unconventional oil/gas stimulation (hydraulic fracturing) operations, it is amplified under the extreme temperatures found in enhanced geothermal systems (EGS). This work demonstrates proof-of-concept of a novel, CO2-responsive, lightweight sintered-bauxite/polymer core/shell proppant. The polymer shell has two main roles; (1) increase the stability of the proppant dispersion in water without the addition of rheology modifiers, and (2) once at the fracture network react with CO2 to promote particle aggregation and prop fractures open. In this work, both roles are demonstrated together with the thermal and chemical stability of the materials showing the potential of these CO2-responsive proppants as an alternative proppant technology for geothermal and unconventional oil/gas applications.

ANALYSIS OF DEPOSITION FROM PARAFFIN-SOLVENT MIXTURES UNDER TURBULENT FLOW

Paraffin deposition is a common problem in the flow of paraffinic and heavy oils. Solids deposition in the pipe wall results in rising process costs due to an increase in energy cost of pumping, a decrease in production, an increase in pressure on the line and risk pipeline blockage. In this work, a simulator was developed to allow the analysis of paraffin deposition under different operating conditions, to understand the influence of the variables (inlet and external temperatures, wax appearance temperature, composition, and time) on paraffin deposition under turbulent flow. A mathematical model for quantitative prediction of wax deposition for paraffin-solvent mixtures was proposed. The methods used in the estimation of physical, thermal, and transport properties of mixtures were suitable when compared with literature data. The simulator calculated the profiles of temperature and thickness of the deposit, with consistent results. The results showed the important role of operating temperatures in paraffin deposition.