Dynamic and Power Generation Features of A Wind-Wave Hybrid System Consisting of A Spar-Type Wind Turbine and An Annular Wave Energy Converter in Irregular Waves

Combining wave energy converters(WECs)with floating offshore wind turbines proves a potential strategy to achieve better use of marine renewable energy.The full coupling investigation on the dynamic and power generation features of the hybrid systems under operational sea states is necessary but limited by numerical simulation tools.Here an aero-hydro-servo-elastic coupling numerical tool is developed and applied to investigate the motion,mooring tension,and energy conversion performance of a hybrid system consisting of a spar-type floating wind turbine and an annular wave energy converter.Results show that the addition of the WEC has no significant negative effect on the dynamic performance of the platform and even enhances the rotational stability of the platform.For surge and pitch motion,the peak of the spectra is originated from the dominating wave component,whereas for the heave motion,the peak of the spectrum is the superposed effect of the dominating wave component and the resonance of the system.The addition of the annular WEC can slightly improve the wind power by making the rotor to be in a better position to face the incoming wind and provide considerable wave energy production,which can compensate for the downtime of the offshore wind.

Short-term power generation scheduling rules for cascade hydropower stations based on hybrid algorithm

Power generation dispatching is a large complex system problem with multi-dimensional and nonlinear characteristics. A mathematical model was established based on the principle of reservoir operation. A large quantity of optimal scheduling processes were obtained by calculating the daily runoff process within three typical years, and a large number of simulated daily runoff processes were obtained using the progressive optimality algorithm （POA） in combination with the genetic algorithm （GA）. After analyzing the optimal scheduling processes, the corresponding scheduling rules were determined, and the practical formulas were obtained. These rules can make full use of the rolling runoff forecast and carry out the rolling scheduling. Compared with the optimized results, the maximum relative difference of the annual power generation obtained by the scheduling rules is no more than 1%. The effectiveness and practical applicability of the scheduling rules are demonstrated by a case study. This study provides a new perspective for formulating the rules of power generation dispatching.

Solving open vehicle problem with time window by hybrid column generation algorithm

This paper addresses the open vehicle routing problem with time window(OVRPTW), where each vehicle does not need to return to the depot after completing the delivery task.The optimization objective is to minimize the total distance. This problem exists widely in real-life logistics distribution process.We propose a hybrid column generation algorithm(HCGA) for the OVRPTW, embedding both exact algorithm and metaheuristic. In HCGA, a label setting algorithm and an intelligent algorithm are designed to select columns from small and large subproblems, respectively. Moreover, a branch strategy is devised to generate the final feasible solution for the OVRPTW. The computational results show that the proposed algorithm has faster speed and can obtain the approximate optimal solution of the problem with 100 customers in a reasonable time.

Allocation of Hybrid Distributed Generations and Energy Management in Radial Electrical Systems

This paper presents a method for optimal sizing of a Micro grid connected to a hybrid source to ensure the continuity and quality of energy in a locality with a stochastically changing population. The hybrid system is composed of a solar photovoltaic system, a wind turbine, and an energy storage system. The reliability of the system is evaluated based on the voltage level regulation on IEEE 33-bus and IEEE 69-bus standards. Power factor correction is performed, despite some reliability and robustness constraints. This work focuses on energy management in a hybrid system considering climatic disturbances on the one hand, and on the other hand, this work evaluates the energy quality and the cost of energy. A combination of genetic algorithms of particle swarm optimization (CGAPSO) shows high convergence speed, which illustrates the robustness of the proposed system. The study of this system shows its feasibility and compliance with standards. The results obtained show a significant reduction in the total cost of production of this proposed system.

A Novel Cascaded PID Controller for Automatic Generation Control Analysis With Renewable Sources

Present day power scenarios demand a high quality uninterrupted power supply and needs environmental issues to be addressed. Both concerns can be dealt with by the introduction of the renewable sources to the existing power system. Thus, automatic generation control(AGC) with diverse renewable sources and a modified-cascaded controller are presented in the paper.Also, a new hybrid scheme of the improved teaching learning based optimization-differential evolution(hITLBO-DE) algorithm is applied for providing optimization of controller parameters. A study of the system with a technique such as TLBO applied to a proportional integral derivative(PID), integral double derivative(IDD) and PIDD is compared to hITLBO-DE tuned cascaded controller with dynamic load change.The suggested methodology has been extensively applied to a 2-area system with a diverse source power system with various operation time non-linearities such as dead-band of, generation rate constraint and reheat thermal units. The multi-area system with reheat thermal plants, hydel plants and a unit of a wind-diesel combination is tested with the cascaded controller scheme with a different controller setting for each area. The variation of the load is taken within 1% to 5% of the connected load and robustness analysis is shown by modifying essential factors simultaneously by± 30%. Finally, the proposed scheme of controller and optimization technique is also tested with a 5-equal area thermal system with non-linearities. The simulation results demonstrate the superiority of the proposed controller and algorithm under a dynamically changing load.

Magnetohydrodynamics hemodynamics hybrid nanofluid flow through inclined stenotic artery

The present study aims to perform computational simulations of twodimensional(2D)hemodynamics of unsteady blood flow via an inclined overlapping stenosed artery employing the Casson fluid model to discuss the hemorheological properties in the arterial region.A uniform magnetic field is applied to the blood flow in the radial direction as the magneto-hemodynamics effect is considered.The entropy generation is discussed using the second law of thermodynamics.The influence of different shape parameters is explored,which are assumed to have varied shapes(spherical,brick,cylindrical,platelet,and blade).The Crank-Nicolson scheme solves the equations and boundary conditions governing the flow.For a given critical height of the stenosis,the key hemodynamic variables such as velocity,wall shear stress(WSS),temperature,flow rate,and heat transfer coefficient are computed.

Cascade utilization of full spectrum solar energy for achieving simultaneous hydrogen production and all-day thermoelectric conversion

Solar-driven photocatalytic water/seawater splitting holds great potential for green hydrogen production.However,the practical application is hindered by the relatively low conversion efficiency resulting from the inadequate utilization of solar spectrum with significant waste in the form of heat.Moreover,current equipment struggles to maintain all-day operation subjected to the lack of light during nighttime.Herein,a novel hybrid system integrating photothermal catalytic(PTC)reactor,thermoelectric generator(TEG),and phase change materials(PCM)was proposed and designed(named as PTC-TEG-PCM)to address these challenges and enable simultaneous overall seawater splitting and 24-hour power generation.The PTC system effectively maintains in an optimal temperature range to maximize photothermal-assisted photocatalytic hydrogen production.The TEG component recycles the low-grade waste heat for power generation,complementing the shortcoming of photocatalytic conversion and achieving cascade utilization of full-spectrum solar energy.Furthermore,exceptional thermal storage capability of PCM allow for the conversion of released heat into electricity during nighttime,contributing significantly to the overall power output and enabling PTC-TEG-PCM to operate for more than 12 h under the actual condition.Compared to traditional PTC system,the overall energy conversion efficiency of the PTC-TEG-PCM system can be increased by∼500%,while maintaining the solar-to-hydrogen efficiency.The advancement of this novel system demonstrated that recycling waste heat from the PTC system and utilizing heat absorption/release capability of PCM for thermoelectric application are effective strategies to improve solar energy conversion.With flexible parameter designing,PTC-TEG-PCM can be applied in various scenarios,offering high efficiency,stability,and sustainability.

A hybrid fuel cell for water purification and simultaneously electricity generation

The development of highly efficient energy conversion technologies to extract energy from wastewater is urgently needed,especially in facing of increasing energy and environment burdens.Here,we successfully fabricated a novel hybrid fuel cell with BiOCl-NH_(4)PTA as photocatalyst.The polyoxometalate(NH_(4)PTA)act as the acceptor of photoelectrons and could retard the recombination of photogenerated electrons and holes,which lead to superior photocatalytic degradation.By utilizing BiOCl-NH_(4)PTA as photocatalysts and Pt/C air-cathode,we successfully constructed an electron and mass transfer enhanced photocatalytic hybrid fuel cell with flow-through field(F-HFC).In this novel fuel cell,dyes and biomass could be directly degraded and stable power output could be obtained.About 87%of dyes could be degraded in 30 min irradiation and nearly 100%removed within 90 min.The current density could reach up to~267.1μA/cm^(2);with maximum power density(Pmax)of~16.2μW/cm^(2) with Rhodamine B as organic pollutant in F-HFC.The power densities were 9.0μW/cm^(2),12.2μW/cm^(2),and 13.9μW/cm^(2) when using methyl orange(MO),glucose and starch as substrates,respectively.This hybrid fuel cell with BiOCl-NH_(4)PTA composite fulfills the purpose of decontamination of aqueous organic pollutants and synchronous electricity generation.Moreover,the novel design cell with separated photodegradation unit and the electricity generation unit could bring potential practical application in water purification and energy recovery from wastewater.

Simulation of large-scale numerical substructure in real-time dynamic hybrid testing

A solution scheme is proposed in this paper for an existing RTDHT system to simulate large-scale finite element （FE） numerical substructures. The analysis of the FE numerical substructure is split into response analysis and signal generation tasks, and executed in two different target computers in real-time. One target computer implements the response analysis task, wherein a large time-step is used to solve the FE substructure, and another target computer implements the signal generation task, wherein an interpolation program is used to generate control signals in a small time-step to meet the input demand of the controller. By using this strategy, the scale of the FE numerical substructure simulation may be increased significantly. The proposed scheme is initially verified by two FE numerical substructure models with 98 and 1240 degrees of freedom （DOFs）. Thereafter, RTDHTs of a single frame-foundation structure are implemented where the foundation, considered as the numerical substructure, is simulated by the FE model with 1240 DOFs. Good agreements between the results of the RTDHT and those from the FE analysis in ABAQUS are obtained.

Second Law Analysis of Magneto Radiative GO-MoS_(2)/H_(2)O–(CH_(2)OH)_(2) Hybrid Nanofluid

Entropy Generation Optimization(EGO)attained huge interest of scientists and researchers due to its numerous applications comprised in mechanical engineering,air conditioners,heat engines,thermal machines,heat exchange,refrigerators,heat pumps and substance mixing etc.Therefore,the study of radiative hybrid nanofluid(GO-MoS_(2)/C_(2)H_(6)O_(2)–H_(2)O)and the conventional nanofluid(MoS_(2)/C_(2)H_(6)O_(2)–H_(2)O)is conducted in the presence of Lorentz forces.The flow configuration is modeled between the parallel rotating plates in which the lower plate is permeable.The models which govern the flow in rotating system are solved numerically over the domain of interest and furnished the results for the temperature,entropy generation and thermophysical characteristics of the hybrid as well as conventional nanofluids,respectively.It is examined that the thermal profile intensifies against stronger thermal radiations and magnetic field.The surface of the plate is heated due to the imposed thermal radiations and magnetic field which cause the increment in the temperature.It is also observed that the temperature declines against more rotating plates.Further,the entropy production increases for more dissipative effects and declines against more magnetized fluid.Thermal conductivities of the hybrid nanofluid enhances promptly in comparison with regular liquid therefore,under consideration hybrid nanofluid is reliable for the heat transfer.Moreover,dominating thermal transport is perceived for the hybrid nanofluid which showed that hybrid suspension GO-MoS_(2)/C_(2)H_(6)O_(2)–H_(2)O is better for industrial,engineering and technological uses.

Figure of Merit Analysis of a Hybrid Solar-geothermal Power Plant

Figure of merit analysis is a general methodology used to evaluate whether a hybrid power plant could produce more power than two stand-alone power plants. In this paper, the assessment methodology using figure of merit analysis was re-examined for a hybrid solar-geothermal power plant. A new definition of the figure of merit was introduced specifically for a solar boosted geothermal plant to include both the technical and economic factors. The new definition was then applied in a case study of a hypothetical demonstration hybrid solar-geothermal power plant in Australia. The power plant was considered to have a typical net power output of 2.2 MW with a solar energy fraction of 27%. The analysis was performed to compare the power output and capital cost of the hybrid plant with the state-of-the-art (SoA) and existing stand-alone solar and geothermal plants. Based on the new definition, the hybrid plant was found to generally outperform the two existing stand-alone plants. Moreover, at an ambient temperature of 5 °C, the hybrid plant was found to outperform the SoA stand-alone plants when the geothermal temperature was greater than 150 °C. For geothermal temperature of 180 °C on the other hand, the hybrid plant outperformed the SoA stand-alone plants at ambient temperatures lower than 33 °C.

Enabling Hybrid Projects through Appropriate Market Design

Large-scale hybrid power plants, composed of two or more generation sources and with the participation of energy storage systems, have driven important electricity Market Design regulation discussions worldwide. Regulatory framework ought to be adapted to support technical particularities of these new generation arranges. This paper presents an assessment of the main requirements to be met by Market Design to enable hybrid power plants by means of assertive market incentives. Assessing regulatory adjustments promoted in Australia, United States, India, China, and Brazil, emphasizing the latter one, the authors presents a case study by applying specific computational simulation and optimization model to a hybrid Hydro-Solar plant, that supports the findings for the necessary evolution needed in the national regulatory framework in order to enable hybrid projects. The evaluation of international experiences indicates that the insertion of hybrid projects is associated with the design of the market they belong to and demand regulatory adjustments so that their attributes can be properly valued for the benefit of all stakeholders, especially for the electricity consumer.

A 3D hybrid grid generation technique and a multigrid/parallel algorithm based on anisotropic agglomeration approach

A hybrid grid generation technique and a multigrid/parallel algorithm are presented in this paper for turbulence flow simulations over three-dimensional （3D） complex geometries. The hybrid grid generation technique is based on an agglomeration method of anisotropic tetrahedrons. Firstly, the complex computational domain is covered by pure tetrahedral grids, in which anisotropic tetrahedrons are adopted to discrete the boundary layer and isotropic tetrahedrons in the outer field. Then, the anisotropic tetrahedrons in the boundary layer are agglomerated to generate prismatic grids. The agglomeration method can improve the grid quality in boundary layer and reduce the grid quantity to enhance the numerical accuracy and efficiency. In order to accelerate the convergence history, a multigrid/parallel algorithm is developed also based on anisotropic agglomeration approach. The numerical results demonstrate the excellent accelerating capability of this multigrid method.

Integrated generation-transmission expansion planning for offshore oilfield power systems based on genetic Tabu hybrid algorithm

To address the planning issue of offshore oil-field power systems, an integrated generation-transmission expansion planning model is proposed. The outage cost is considered and the genetic Tabu hybrid algorithm(GTHA)is developed to find the optimal solution. With the proposed integrated model, the planning of generators and transmission lines can be worked out simultaneously,which outweighs the disadvantages of separate planning,for instance, unable to consider the influence of power grid during the planning of generation, or insufficient to plan the transmission system without enough information of generation. The integrated planning model takes into account both the outage cost and the shipping cost, which makes the model more practical for offshore oilfield power systems. The planning problem formulated based on the proposed model is a mixed integer nonlinear programming problem of very high computational complexity, which is difficult to solve by regular mathematical methods. A comprehensive optimization method based on GTHA is also developed to search the best solution efficiently.Finally, a case study on the planning of a 50-bus offshore oilfield power system is conducted, and the obtained results fully demonstrate the effectiveness of the presented model and method.

Influences of double diffusion upon radiative flow of thin film Maxwell fluid through a stretching channel

This work explores the influence of double diffusion over thermally radiative flow of thin film hybrid nanofluid and irreversibility generation through a stretching channel.The nanoparticles of silver and alumina have mixed in the Maxwell fluid(base fluid).Magnetic field influence has been employed to channel in normal direction.Equations that are going to administer the fluid flow have been converted to dimension-free notations by using appropriate variables.Homotopy analysis method is used for the solution of the resultant equations.In this investigation it has pointed out that motion of fluid has declined with growth in magnetic effects,thin film thickness,and unsteadiness factor.Temperature of fluid has grown up with upsurge in Brownian motion,radiation factor,and thermophoresis effects,while it has declined with greater values of thermal Maxwell factor and thickness factor of the thin film.Concentration distribution has grown up with higher values of thermophoresis effects and has declined for augmentation in Brownian motion.

Analytical Hybrid Particle Swarm Optimization Algorithm for Optimal Siting and Sizing of Distributed Generation in Smart Grid

In this paper,the hybridization of standard particle swarm optimisation(PSO)with the analytical method(2/3 rd rule)is proposed,which is called as analytical hybrid PSO(AHPSO)algorithm used for the optimal siting and sizing of distribution generation.The proposed AHPSO algorithm is implemented to cater for uniformly distributed,increasingly distributed,centrally distributed,and randomly distributed loads in conventional power systems.To demonstrate the effectiveness of the proposed algorithm,the convergence speed and optimization performances of standard PSO and the proposed AHPSO algorithms are compared for two cases.In the first case,the performances of both the algorithms are compared for four different load distributions via an IEEE 10-bus system.In the second case,the performances of both the algorithms are compared for IEEE 10-bus,IEEE 33-bus,IEEE 69-bus systems,and a real distribution system of Korea.Simulation results show that the proposed AHPSO algorithm converges significantly faster than the standard PSO.The results of the proposed algorithm are compared with those of an analytical algorithm,and the results of them are similar.

Hybrid grid generation for viscous flow simulations in complex geometries

In this paper,we present a hybrid grid generation approach for viscous flow simulations by marching a surface triangulation on viscous walls along certain directions.Focuses are on the computing strategies used to determine the marching directions and distances since these strategies determine the quality of the resulting elements and the reliability of the meshing procedure to a large extent.With respect to marching directions,three strategies featured with different levels of efficiencies and robustness performance are combined to compute the initial normals at front nodes to balance the trade-off between efficiency and robustness.A novel weighted strategy is used in the normal smoothing scheme,which evidently reduces the possibility of early stop of front generation at complex corners.With respect to marching distances,the distance settings at concave and/or convex corners are locally adjusted to smooth the front shape at first;a further adjustment is then conducted for front nodes in the neighbourhood of gaps between opposite viscous boundaries.These efforts,plus other special treatments such as multi-normal generation and fast detection of local/global intersection,as a whole enable the setup of a hybrid mesher that could generate qualitied viscous grids for geometries with industry-level complexities.

Alien DNA introgression and wheat DNA rearrangements in a stable wheat line derived from the early generation of distant hybridization

Polyploidy has been found to be common in plants. Bread or common wheat (Triti-cum aestivum L., 2n = 42) is a good example of allopolyploid made up of three diploid genomes A, B and D. In recent years, by the study of mimicking the origination of common wheat, it was found that changes of DNA sequence and gene expression occurred at the early stages of artifi-cial allohexaploid between tetraploid wheat and Aegilops tauschii, which was probably favorable to genetic diploidization of new synthetic hexaploid wheat. Common wheat 99L2 is a new line stable in genetic, which was derived from the early self-pollinated generation of wide hybrids between common wheat and rye. In this study, it was found that at least two rye DNA segments had been introgressed into 99L2. This result suggested that a mechanism of alien DNA intro-gression may exist, which was different from the traditional mechanism of chromosome pairing and DNA recombination between wheat and alien species. Meanwhile, during the introgression process of alien rye DNA segments, the changes in DNA sequences of wheat itself occurred.

Nonlinear hybrid plasmonic slot waveguide for second-harmonic generation

A nonlinear hybrid plasmonic slot waveguide composed of periodically poled lithium niobate(PPLN) and two separated silver films is investigated. The e?ective refractive index, propagation length, and energy confinement of the hybrid anti-symmetric mode in this waveguide are calculated using the structure parameters at the fundamental wavelength of λ = 1550 nm and its second harmonic(SH) λ = 775 nm. Through the above indices, coupling e?ciency(maximum SH conversion e?ciency during propagation) and peak position(propagation location of the conversion e?ciency) of SH generation are analyzed. Finally, higher conversion e?ciency can be achieved at a shorter propagation distance by changing the waveguide into a tapered structure.

Entropy generation for mixed convection flow in vertical annulus with two regions hydromagnetic viscous and Cu-Ag water hybrid nanofluid through porous zone: a comparative numerical study

The primary determination of this study is a numerical investigation of the entropygeneration (EG) in the steady two-region flow of viscous fluid and hybrid nanofluid (NF) in along-infinite vertical annulus having a clear region as well as porous media. Stoke’s and single-phase NF models are used to study the viscous fluid and hybrid nanofluid (HNF) heat transferdevelopments, respectively. Two types of nanoparticles are taken, such as copper (Cu) and sil-ver (Ag) within base fluid water to make it a HNF. Darcy-Brinkman law is also used to examinethe flow through the porous zone in the annulus. Necessary quantities have been used in thesystem of equations to transfer them into non-dimensional forms. For momentum and energytransport, the numerical results are evaluated for various model parameters and are examinedvia the shooting method in MATHEMATICA. It is noted that the momentum and energy trans-port are more significant when two immiscible fluids in a clear vertical annulus are taken. Thefindings also indicate that two-phase momentum and heat flow are greater when a NF is used in Region-II and lower when a HNF is used. The temperature (in Region-II) falls with a high na-nomaterials volume fraction (see Figure 4) while it is increased when the Hartman number isincreased. Moreover, velocity declines with increment in nanomaterials volume fraction. Thus,higher thermal conductivity can be accomplished by using a magnetic field.