Hydraulic Energy Research Articles

Frequency Modulation Control of Hydraulic Wind Turbines Based on Ocean Used Wind Turbines and Energy Storage

Based on the energy storage type of hydraulic wind turbines (HWTs) and in view of the unit frequency drop problem under high wind power proportion conditions, this paper proposes a method of primary frequency control under maximum power point tracking (MPPT). HWT power output is affected by wind speed randomness and volatility. In addition, traditional wind turbines do not have inertial adjustment ability, leading to a decrease in the frequency stability of the power system caused by the increase in wind power permeability. In the paper, a hydraulic energy storage system and synchronous generator are combined to carry out primary frequency modulation, and a mathematical model of the hydraulic energy storage system, the hydraulic main transmission system, and the generator active power regulation system after grid connection is established. By analyzing the load changing rules of power systems and frequency fluctuation caused by the power system load after the wind turbine is grid-connected, the variable parameter frequency modulation compensation control strategy of combined turbine-energy storage systems is established, and simulation verification under different load fluctuations is carried out, verifying the effectiveness of the frequency modulation control strategy, which achieves a good control effect for improving the frequency modulation ability of hydraulic wind turbines.

Recent developments in the optimization of Francis turbine components for minimizing sediment erosion

Sediment erosion in hydraulic turbines are severe in case of hydropower plants operating in Himalayan Rivers of Nepal. Francis turbine components are heavily eroded while hard particles as quartz flow along with water through the water conduit in power plant. In Francis turbines, the runner blades where significant portion of hydraulic energy converts in mechanical energy are heavily eroded. This is due to complexity in fluid flow while operated at different operating conditions with sediment contained water. Conventional design of Francis turbines has overlooked on the effects of sediment erosion while considering optimum efficiency at all operating conditions. This paper examines multi-objective optimization of a reference 92 kW model Francis runner for minimizing sediment erosion effects. The model turbine studied in this paper is a scale down model turbine of Jhimruk Hydropower Plant, Nepal that is severely affected by sediment erosion. It was found that sediment erosion was reduced significantly at part load, full load and best efficiency point with improvement in hydraulic performance for model turbine utilizing multi-objective optimization on runner blade design.

Analysis of Flow Channel Structure Parameter and Optimization Study on Tooth Spacing of Drip Irrigation Tape

The flow channel structure is the main factor affecting the hydraulic performance, anti-clogging and energy dissipation performance of drip irrigation tape. Proper exploring of the performance-related but hard-to-measure structure parameters in the flow channel emitter of drip irrigation tape is imperative. However, the traditional studying methods may lead to large systematic errors and human errors, resulting in inaccurate estimations of the parameters and an unreasonable design. This paper aims to find an effective way to optimize the most significant channel structural parameter through studying 18 kinds of drip irrigation belts commonly used in the agricultural irrigation field. Unigraphics NX and Spaceclaim were applied to measure the eight main structure parameters of the selected drip irrigation tapes. The one critical parameter that affects the emitter hydraulic performance—tooth spacing—was found by Principal Component Analysis (PCA). Therefore, we designed three plans where the tooth spacing decreased by 0.1, 0.2, and 0.29 mm to 1.36, 1.26, and 1.17 mm, respectively, and, finally, formed two types of flow channels. Flow channel 1 with a tooth base is represented by Plan 1 and Plan 2, and flow channel 2 without a tooth base is represented by Plan 3. Then, computational fluid dynamics (CFD) was used to simulate the flow characteristics of the emitters in the three plans. The results demonstrate that flow channel 2 without a tooth base, represented by Plan 3, has a greater kinetic energy and hydraulic performance than flow channel 1. Compared with the control group, the changes in Plan 3 were the most obvious, with the changes in the flow index, flow coefficient, and average flow rate by −14.50%, −5.08%, and 12.50%, respectively. The flow indexes in the three plans are all less than 0.5, while the smallest of Plan 3 is 0.395. Therefore, the hydraulic performance of flow channel 2 represented by Plan 3 is better. The narrowing of the tooth spacing makes the space for vortexing between the serrated teeth smaller. The flow velocity in Plan 3 is generally increased by 3 m/s from 2.3 to 4.1 m/s, becoming more uniform. Due to a high velocity of the water flow and less vortexing, the deposition of suspended solids in the flow channel is avoided to a certain extent, and for the flow channel in Plan 3, the improvement in the hydraulic performance is greater than the reduction in the energy dissipation performance. The ratio of the decrease in the flow index to the increase in the average outflow of the emitter in Plan 3 is 1.16:1. In conclusion, the overall performance of Plan 3 is optimal for all schemes. Flow channel 2 can improve the hydraulic performance and reduce the production costs. Therefore, this study could provide a theoretical induction for inner drip irrigation tape application and production.

Low-Head Hydropower for Energy Recovery in Wastewater Systems

Hydraulic turbines for energy recovery in wastewater treatment plants, with relatively large discharges values and small head jumps, are usually screw Archimedes or Kaplan types. In the specific case of a small head jump (about 3 m) underlying a rectangular weir in the major Palermo (Italy) water treatment plant, a traditional Kaplan solution is compared with two other new proposals: a Hydrostatic Pressure Machine (HPM) located at the upstream channel and a cross-flow turbine (CFT) located in a specific underground room downstream of the same channel. The fluid mechanical formulations of the flow through these turbines are analyzed and the characteristic parameters are stated. Numerical analysis was carried out for the validation of the HPM design criteria. The efficiency at the design point of the CFT and HPM are estimated using the ANSYS CFX solver for resolution of 3D URANS analysis. The strong and weak points of the three devices are compared. Finally, a viability analysis is developed based on several economic indicators. This innovative study with a theoretical formulation of the most suitable turbomachine characterization, the potential energy estimation based on hydraulic energy recovery in a real case study of a wastewater treatment plant and the comparison of the three different low-head turbines, enhancing the main advantages, is of utmost importance towards the net-zero water sector decarbonization.

The Structure Principle and Dynamic Characteristics of Mechanical-Electric-Hydraulic Dynamic Coupling Drive System and Its Application in Electric Vehicle

To solve the problem of the low recovery rate of braking energy and the short driving range of electric vehicles, a novel mechanical-electric-hydraulic dynamic coupling drive system (MEH-DCDS) is proposed in this article. MEH-DCDS is a new power integration device that allows electric, mechanical, and hydraulic energy to be converted mutually. It comprises a swash plate plunger pump/motor and a permanent magnet synchronous motor. This article explains the structure and working principles of MEH-DCDS. We describe the dynamic characteristics of MEH-DCDS and analyze the pump and hydraulic motor in the MEH-DCDS hydraulic module. The simulation results show that the flow variation of the MEH-DCDS hydraulic module accords with the design concept of MEH-DCDS, and the pressure variation of high and low pressure accumulators also accords with the theoretical situation. The energy flow of Mechanical-Electric-Hydraulic Power Coupling Electric Vehicle (MEHPC-EV) under different working modes is expounded, and the mathematical model of its key components is established. Based on AMESim and Simulink, the article establishes a vehicle simulation dynamic model. The dynamic performance of MEHPC-EV in UDDS is analyzed by co-simulation. The simulation results show that the application of MEH-DCDS in electric vehicles is feasible. MEHPC-EV reduced battery energy consumption by 26.18% compared to EV. The research in this paper verifies the accuracy and superiority of the system, which has a significant reference value for the development and study of electric vehicles in the future.

Super-rated operational concept for increased wind turbine power with energy storage

• New method of Region 3 operation proposed to increase power production. • Hydraulic transmission and energy storage proposed to decouple rotor and generator. • Super-rated operation has the potential to increase energy production by 23% • Capacity factor may increase from 53% to 66% without increasing generator size. • This system will require solving several hydraulic transmission engineering issues. A new super-rated method of wind turbine control is proposed for operation between rated and cut-out wind speeds, in conjunction with integrated energy storage, that may allow dramatically increased power capture as well as improved energy dispatchability without increasing turbine size or generator size. In the proposed system, a hydraulic transmission is used to decouple the wind turbine rotor from the electric generator, allowing for mechanical energy storage to be integrated into the system before the generator. Rather than the conventional Region 3 control, the new super-rated Region 3 + operation allows the rotor to generate additional power above the rated power limit and store that additional power for later regeneration. In this Region 3+ operation, the limit on operation is based on rotor thrust loads (instead of rotor power) so that power can increase with increasing wind speed. A case study with the NREL 5 MW reference turbine in steady Class I winds showed that super-rated operation could increase annual power production by 23% (including hydraulic transmission storage losses), without increasing mean out-of-plane blade loads, rotor size, or generator power. In addition, this new operation for this case increases the capacity factor from 53% to 66%, which increases power levelization. However, a wide array of component design issues must be addressed (especially for the hydraulic drivetrain) to determine if this potential can be realized.

Power Parametric Optimization of an Electro-Hydraulic Integrated Drive System for Power-Carrying Vehicles Based on the Taguchi Method

Focused on the troubles and defects introduced by the traditional single form of electric vehicle transmission, this paper proposes an electro-hydraulic power coupled electric vehicle based on the working principle of an electro-hydraulic power integrated drive system for light-duty cargo vehicles. The integration of the planetary row into the drive system allows the interconversion of mechanical, electrical, and hydraulic energy. By describing the system structure and composition, several working conditions during automobile driving are proposed, and the working principle of every circumstance is introduced. Simultaneously, the article determines the preliminary optimal ratio with the battery’s state of charge (SOC) as the constraint. Then, the orthogonal test matrix of electro-hydraulic ratios and speed thresholds for each operating condition is established according to Taguchi’s method. The impact of each optimized parameter on the motor torque and hydraulic torque as well as the SOC and the proportion of the effect is evaluated by the simulation to obtain the optimal solution. The simulation consequences show that the motor torque and hydraulic torque are reduced, and thus, the vehicle’s acceleration performance and energy recovery efficiency are improved.

Mode Switching Frequency of Electrohydraulic-Power-Coupled Electric Vehicles with Different Delay Control Times

The variability of vehicle operating conditions and the multiplicity of coupler dynamics inevitably increase the frequency and complexity of cooperative power control. In this study, a novel electromechanical–hydraulic-power-coupled electric vehicle is developed and investigated. This vehicle integrates a conventional electric motor with a hydraulic pump/motor to interconvert electrical, mechanical, and hydraulic energies, while a rule-based dynamic optimal energy management strategy is designed to achieve dynamic switching of operating modes according to the operating conditions. Thus, the power-switching sensitivity is reduced by adding a delay determination link to the Stateflow. Results show that the addition of the delay link has a small effect on classical road conditions and significant suppression of road conditions with high-power-switching frequency. Therefore, the method proposed in this paper improves the energy efficiency, stability, and economic performance of electrohydraulic-power-coupled electric vehicles, which will hopefully provide a good reference for the development of electrohydraulic vehicles.

An uneven rhodolith distribution controlled by sea-bottom conditions near Jeju Island, Korea

Actively growing, dense rhodolith beds are found in the wide channel between the volcanic Jeju and Udo islands in Korea. This shallow area (water depths of up to 25 m) has unique geological features affected by the marine hydraulic regime. Spheroidal and sub-spheroidal, living or dead rhodoliths with the size range from sand to pebble are common (mostly 2–4 cm in diameter), but some of them are actively growing up to over 10 cm. Most sand- to granule-sized sediments are characterized by nonliving fragments, and the pebble-sized sediment beds are a mixture. In order to understand the factors affecting the characteristics (morphology, distribution, the living portion of rhodoliths, etc.) Seabed topography and sedimentary texture associated with hydraulic energy were investigated. We divided the study area into four types based on topographical properties. Among these classifications, the “Flat plain” and “Gentle slope” geomorphic categories have dense rhodolith beds, whereas a low distribution of rhodoliths was identified in areas with uneven topography or extreme high hydraulic energy flux. In addition, rhodolith growth was affected by the size of carbonate grains on the seafloor, and rhodoliths with more spheroidal shapes tend to occur on flatter floors. This study delineates that the substrate with coarse-sized substrate at relatively deeper water depth as well as flatter bottom topography provides favorable conditions for continuous growth of rhodoliths. Our findings will help the understanding of the growth conditions of rhodoliths in other parts of the world.

Biopolymer-biocement composite treatment for stabilisation of soil against both current and wave erosion

Increased frequency of extreme weather events has made the conservation of riverbanks and coastlines a global concern. Soil stabilisation via microbially induced calcite precipitation (MICP) is one of the most eco-suitable candidates for improving resilience against erosion. In this study, the erosion characteristics of soil treated with various levels of biocementation are investigated. The samples were subjected to hydraulic flow in both tangential and perpendicular directions in a flume to simulate riverbank and coastal situations. Soil mass loss, eroded volume, and cumulative erosion rates of the treated soil against the applied hydraulic energy density have been reported. Post erosion exposure, the residual soil has been assessed for its properties using needle penetration resistance, precipitated calcium carbonate content and microstructure. It was observed that soil erosion declined exponentially with the increase in calcium carbonate content against the perpendicular waves. However, biocementation leads to brittle fracture beyond a threshold, limiting its efficacy, especially against the tangential waves. Additional composite treatment with a biopolymer was found to improve the resilience of the soil specimens against erosion. The composite treatment required half of the quantity of the biocementing reagents in comparison to the equally erosion-resistant plain biocemented sample. Therefore, stoichiometrically the composite treatment is likely to yield 50% lesser ammonia than plain biocement treatment. This investigation unravels a promising soil conservation technique via the composite effect of biocement and biopolymer.

Methodology for the Development of Hybrid Renewable Energy Systems (HRES) with Pumped Storage and Hydrogen Production on Lemnos Island

The non-interconnected islands of Greece can benefit from the comprehensive use of RES to avoid water droughts and ensure energy autonomy. The present paper analyzes an HRES with two possible operating scenarios. Both of them include a wind park of 27.5 MW capacity, an 1175 m3/day desalination plant, and a 490,000 m3/day water tank in Lemnos, Greece. Regarding the wind power, 70% is used in the HRES, while the rest is channeled directly to the grid. The main difference comes down to how the wind energy is stored, either in the form of hydraulic energy or in the form of hydrogen. The lifespan of the system is 25 years, such as the produced stochastic series of rainfall, temperature, and wind of the area. Through the comparison of the operating scenarios, the following results arise: (i) the water needs of the island are fully covered and the irrigation needs have a reliability of 66%, in both scenarios. (ii) Considering the energy needs, the pumping storage seems to be the most reliable solution. (iii) However, depending on the amount of wind energy surplus, the use of hydrogen could produce more energy than the hydroelectric plant.

Study on Complexity Planning Model of Pumped Storage in Abandoned Open-Pit Mine: A Case Study of Fushun Open-Pit Mine

Open-pit mining is one of the main exploiting methods for solid mineral resources. After more than 100 years of high-intensity development, there are a large number of abandoned open-pit mines and related mining relics in the world. The reconstruction of Pumped Hydraulic Energy Storage systems (PHES) from abandoned open-pit mines is an effective utilization mode of the abandoned underground space in recent years. The project planning of PHES should consider not only the technical and economic feasibility of PHES power station but also a series of problems, such as comprehensive utilization of mine dump, slope treatment, industrial heritage and cultural inheritance, ecological environment restoration of mining area, and transformation and matching of nearby resource-exhausted cities. This constitutes a complex planning problem of pumped storage in abandoned open-pit mines. This paper takes Fushun open-pit mine, the second largest open-pit mine in the world, as the analysis object and abstracts a variety of application modes of pumped storage in abandoned open-pit mines with the model research method. On this basis, the modes abstracted such as the single-pit oil–water co-storage mode, single-pit gravity dam reinforcement mode, multi-pit linkage energy storage mode, and multi-pit and dump linkage energy storage mode are all carefully studied in this paper. A series of supporting integrated programs are proposed for each mode with regard to ecological restoration, multi-energy complementary, cultural tourism governance, etc. In addition, based on the PHES with abandoned open-pit mine, this paper also explores the sustainable development of resource-exhausted cities and the transmission of their core industries.

Influence of distance from water surface of a horizontally installed Savonius turbine in a rectangular open channel on turbine performance

Abstract The aim of this investigation is to develop a nano-hydro turbine that can effectively utilize the wasted hydraulic energy in infrastructure such as agricultural and industrial canals and irrigation waterways. Up to this time, the utilization of such a small hydropower has not progressed owing to economic reasons. Therefore, we focus on the Savonius type, which has the advantages of low manufacturing cost and excellent maintainability because of its simple structure. Conventionally, the Savonius type has been developed and researched as a vertical axis wind turbine. In order to effectively utilize the water surface flow, which is particular to open channels, we place the turbine runner perpendicular to the water flow and horizontally on the channel bottom. In the present study, we experimentally investigated the effect of the parameters for the turbine installation and its operation, namely distance between a runner and the water surface and the rotation direction of the runner, on the performance at each water level. As a result, it was found that the suitable installation depth differs depending on the rotation direction of the turbine.

Rural Policing in the Long Trecento: An Urban Project and Its Obstruction

Abstract The intricacies of urban–rural relations surface with rare detail from the records of Italian field wardens (campari) from the late thirteenth to the mid-fifteenth century. Focusing on the region of Piedmont, in the peninsula’s north-west, this article traces the policing of numerous sites and species by the campari as part of an urban bio- and agropolitical project. The office reflects the growing desire of towns to control their surrounding countryside, not only for military defence, but also as an essential source of calorific and hydraulic energy, a sink for waste and a stage on which to showcase their power before internal and external audiences. Reconstructing the remits, norms and actions of field wardens thus illuminates power negotiations that were shaped by a range of environmental factors and the era’s thinking about hygiene. Yet analysing the activities and responsibilities of the campari also reveals the tactics that rural dwellers devised to contest urban discipline, for instance through self-help, concealment and the embellishment of charges made against them. From the perspective of the area’s historiography, the dynamics captured by these records challenge the centrality of landed aristocracies in narratives of political centralisation. And from a broader perspective, the granular view they afford of middling officials at work invites historians to explore what urbanisation meant at the ground level, on either side of the city walls.

Design and energy analysis of novel hydraulic regenerative potential energy systems

Potential energy regeneration is an important hydraulic energy-saving technology in construction machinery. However, the existing hydraulic regenerative potential energy system (HRPES) is still limited by its large size, high cost, circuit interference, and so on. To solve the above problems, this paper intends to study novel HRPES by optimizing the hydraulic circuits and hydraulic components. First, we design four new HRPESs according to the working characteristics of energy recovery and energy reuse of construction equipment. Based on the load data of the 1.7-ton experimental excavator and the HRPES simulation model, the working characteristics of HRPES in the process of multicycle energy regeneration are studied. Finally, in addition to the conventional energy-saving efficiency, this paper proposes the recovery efficiency, reuse efficiency and regeneration efficiency to comprehensively analyse the energy efficiency characteristics of the four HRPESs. The results show that the energy-saving efficiencies of the four HRPESs are 16.02%, 22.84%, 21.95%, and 27.15% compared with traditional No-HRPES, and the regeneration efficiencies are 54.43%, 57.76%, 53.55%, and 57.97%, respectively. These results have an important reference for optimizing the structure of existing HRPES.

Multi-objective optimization tool for PATs operation in water pressurized systems

ABSTRACT The use of pump working as turbine (PAT) instead of the traditional pressure regulation systems could allow for a recovery of the excess hydraulic energy to reduce the energy footprint of the water supply industry and at the same time control the water losses by an effective reduction in pressure induced by the turbine head drop. This research aims to explore the option of applying multiple recovery systems in a water network with an integrated multi-objective optimization using genetic algorithms. The objective of the optimization is to ensure a better use and effectiveness in the implementation of these solutions. A methodology to approach this multi-objective solution and the interface between components of the optimization is developed and presented. The evolutionary capacities of the optimization is analysed and the effects of the general convergence of the Pareto surface front with the adaptation of the final solutions to the available PATs.

Hydraulic Pressure Ripple Energy Harvesting: Structures, Materials, and Applications (Adv. Energy Mater. 9/2022)

Hydraulic Pressure Energy In article number 2103185, Chris R. Bowen and co-workers present a comprehensive overview of the state-of-the-art in hydraulic pressure energy harvesting, which includes the fundamentals of pressure ripples in hydraulic systems, and the selection of electroactive materials and device structures. In addition, novel approaches for improving the harvested energy and potential applications for the technology are discussed, and future research directions are proposed and outlined.

Revisiting the Indus Basin Model for an Energy Sustainable Pakistan

Water is vital and an essential entity directly and indirectly for all living creatures from their birth, whereas electrical energy has a dominant role in the growth of society in general and for human beings in particular. Optimal use of water and production of electrical energy at minimum cost are potential research challenges. Hydraulic energy is one of the cheapest and the most exploited renewable energy resource for power generation worldwide, and is in line with the seventh United Nations Sustainable Development Goal (SDG 7). The Indus basin is a trans-boundary basin, and its modeling has been a source of interest for scientists and policymakers. Indus Basin Model Revised (IBMR) has many variants, all focusing on optimal use of water for irrigation purposes. In this paper, the modified IBMR model is proposed addressing both agriculture and power generation aspects simultaneously. This model optimizes the Consumer Producer Surplus (CPS) by considering different water inflow probabilities. A parameter has been introduced in the modified objective function to manipulate the supply of water to agriculture and hydropower generation. The proposed model has been implemented in Generic Algebraic Modeling System (GAMS) and case studies have been investigated in presence and absence of power generation. The results obtained show that, with incorporation of hydropower, basin wide income is increased up to 11.83% using 50% exceedance probability, and results are in agreement with reference power generation estimated by National Transmission and Dispatch Company (NTDC). The SDG 7 targets ensure the reasonable, dependable, sustainable and contemporary energy access to all. The current research is focusing on how Pakistan would achieve the SDG 7 targets. By 2040, it is anticipated that Pakistan’s energy mix will have around 40% of hydropower and 16% of renewable energy.

Examining the effect of quantities offered by hydraulic, renewable, non-renewable sources and thermal technologies on electricity prices in the MIBEL market through an ADRL approach

The objective of this article is to analyze and empirically validate the differential effects in the daily schedules of the induced electricity prices by selling bids for three different technologies, namely hydraulic, thermal and renewable energy sources (RES), in hourly values, by daily observations for the year 2018. To achieve this objective, we employ an autoregressive distributed lag (ARDL) model-bound testing approach The results of the ADRL-ECM method, which also reports the long-run analysis, show that (a) the renewable and thermal technologies positively and significantly affect the electricity price for Endesa and Hidroelétrica del Cantábrico generators and (b) the hydraulic technology impacts negatively the electricity price, both at a 1% level of significance. In addition, following a long-term perspective it must be highlighted that RES negatively impact the price of electricity with a 1% level of significance for the Iberdrola, E.ON Energy, Unión Fenosa and EDP Energy of Portugal generators. However based on a short-term perspective, the results report a positive effect between the quantities traded by hydraulic and thermal technologies on the electricity price for Endesa, Iberdrola, Hidroelétrica del Cantábrico and EDP Energy of Portugal, at a 1% level of significance.

A laboratory study on fracture initiation and propagation of granite under cyclic-injection hydraulic fracturing

The abundant geothermal energy in hot dry rock (HDR) geothermal reservoirs is an attractive renewable energy resource with great potential. Cyclic injection in hydraulic fracturing has been proved to be a suitable way for the geothermal energy exploitation. However, the fracture initiation and propagation regimes induced by cyclic injection have been inadequately studied, and the fracturing optimization for HDR is often by experience. For this reason, true tri-axial hydraulic-fracturing tests were conducted to study the initiation and propagation of hydraulic fractures, while the specimens were subjected to the cyclic injection with different cycle time duration and injection rate. The results revealed that the initiation of hydraulic fracture was displayed as three basic patterns, and these fracture-initiation patterns were developed into two fracture geometries: simple fracture with only 2–4 strands and complex fracture network with >4 strands. The main reason for this difference is that the initiation and propagation of hydraulic fracture is controlled by the way of fluid circulation, and the cycle time duration and injection rate each played a different role in hydraulic fracturing. At a low injection rate, the initiation and propagation of hydraulic fractures under the high-frequency cycle (cycle time duration = 10 and 20 s) are mainly controlled by the change of injection pressure. Here, the hydraulic energy mainly acts on the rock near the well. The frequent change of injection pressure promotes the initiation of micro-fractures and forms a complex but short hydraulic fracture network. However, when high injection rate is subjected, too high and too low cycle frequencies (cycle time duration = 5 and 40 s) both tend to form a simple fracture, but the fracture has strong extension ability. With that, the similarity criterion of physical phenomena between the on-site prototype and the experimental model were discussed, and these lab-scale results were translated into the fracturing site of HDR.