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[Display omitted] • A route is proposed to load nanoparticles and electrolyte into ceramic paper separator. • The proposed route is efficient and safe, which can be promoted to used in large scales. • Electrochemical performance of thermal batteries can be obviously improved with ceramic paper as separator. Composites consisted of ceramic paper, nanoparticles as well as molten salt electrolyte, are developed as the new electrolyte separators to substitute the traditional ones in thermal batteries, due to their flexible manufacture and good exhibition in electrochemical performance. However, the existed methods for fabricating the composites by roughly dip-coating with aqueous solutions, are suffering from drawbacks such as inefficiency, low consistence, or high temperature risk. Therefore, a new approach based on a melting-absorption-diffusion process, by using precursors without solvent, is developed. Firstly, the salts are accurately weighted. Then they melt on surfaces of ceramic papers and diffuse inside. After being treated at appropriate temperature for hours, high quality electrolyte separators based on ceramic papers are achieved. Compared to the traditional approaches, the new method can obviously increase and accurately control the amount of loaded nanoparticles and molten salts for each time. The achieved electrolyte separators also exhibit good electrochemical performance in single cells of thermal batteries compared with the traditional ones. With advantages like easy operation, high efficiency, and improved performance, this melting and in situ loading method holds broad prospect in preparing electrolyte separators at large scale. [ABSTRACT FROM AUTHOR]

In this paper, wastepaper gasification with carbon dioxide or steam has been investigated in the presence of molten carbonate catalysts. The reactions of wastepaper with steam or carbon dioxide have been compared. Hydrogen was the main product on the condition of steam used as reactant gas, but in the case where carbon dioxide was used, the amount of carbon monoxide generated from wastepaper gasification greatly increased via the Boudouard reaction. Different ratios of mixtures of lithium, sodium and potassium carbonates as the catalysts have been tested; the lithium carbonate was found to play a critical role. The reaction rate of carbon conversion was approximately first order for low carbon conversions. Both the rate constants and the activation energies have been calculated at different temperatures (923–1023 K). In additions, the flexibility of this technique was examined with three different types of wastepaper. The results suggest that this process can promote effective use of wastepaper and recovery of carbon dioxide. At 1023 K, a high value of cold gas efficiency of about 95% was acquired. [Copyright &y& Elsevier]

A scalable segmented-based proton-exchange membrane fuel cell (PEMFC) hybrid power system model is developed in this paper. The fuel cell (FC) is developed as a dynamic lumped parameter model to predict the current distributions during dynamic load scenarios. The fuel cell is segmented into 3 × 3 segments connected with several physical ports and with the variables balanced automatically. Based on the proposed model, a real-time energy management framework is designed to distribute the load current demand during dynamic operations. Simulation results show that the proposed strategy has good performance on both single/segmented fuel cell–battery hybrid systems and the low battery state of charge (SOC) situation. This paper proposes an approach that uses an interconnected ordinary differential equations (ODEs) system model in control problems, which makes the control algorithms readily applicable. [ABSTRACT FROM AUTHOR]

Locomotive engines serve as the powering heart of rail transportation which is widely used for massive cargo over long distances. The traditional locomotive engines have depended on the internal combustion engine for decades, operated using fossil fuels that negatively impact the environment. Since more and more commodities are transported by trains, the prime engines need to be improved where the fuels are expected to enhance the engine's performance and alleviate the environmental impact. This paper presents a comparison of three developed locomotive engines with different configurations, such as an internal combustion engine combined with a gas turbine and molten carbonate fuel cell (ICE-GT-MCFC), a gas turbine combined with a solid oxide fuel cell and onboard hydrogen production using aluminum electrolysis cell (GT-SOFC), and a GT combined with sold oxide and proton exchange membrane fuel cells (GT–SOFC–PEMFC). The paper then identifies one hybridized engine, which is GT–SOFC–PEMFC, according to its low weight and better performance to conduct an optimization study to enhance its efficiency, reduce the cost, and lower the environmental impact. The present optimization study is undertaken through a multi-objective particle swarm optimization, involving thermodynamic, exergoeconomic, and exergoenvironmental analyses. The optimized GT–SOFC–PEMFC locomotive engine is improved in power from 5.9 MW to 7.3 MW and improved in performance to 49.1% energetic efficiency and 47.0% exergetic efficiency. Additionally, the optimized GT–SOFC–PEMFC engine has less specific fuel and product cost of 24.9 $/GJ and 34.7 $/GJ, respectively, and less specific exergetic environmental impact of fuel and product of 13.2 Pt/GJ and 16.2 Pt/GJ, respectively. Also, the relative cost difference and relative environmental impact difference are significantly reduced by more than 20% to 39.4% and 22.8%, respectively. The operational conditions of the optimized GT–SOFC–PEMFC engine are improved to achieve better efficiency and better cost effectiveness in a more environmentally-benign manner. • Comparison between three hybridized combined locomotive engines is established. • Optimized GT–SOFC–PEMFC engine has 7.3 MW power and 49% energetic efficiency. • Specific exergetic product cost declined to 51 $/GJ for fuel and 35 $/GJ. • Specific exergetic environmental impact for fuel and product becomes 13 and 16 Pt/GJ. • The relative environmental impact difference becomes 22.8% instead of 44.3%. [ABSTRACT FROM AUTHOR]

A carbon fiber-reinforced thermosetting plastic and stainless steel were joined by the fiber laser. The surface texture effect on the joint was investigated. The abrasive paper scratching is shown to form single directional striae on stainless steel with intermittent ridges. Laser texture processing creates uniformly distributed microdimples and ridges, which forms a rectangular cellular structure. This processing can improve the fluidity of molten polyphenylene sulfite during laser joining. Laser scanning on stainless steel results in the formation of fusion and heat-affected zones. In the heat-affected zone, lathy ferrite is located along the boundary, while in the fusion zone, ferrite forms the skeletal structure and separates austenite into a cellular structure. The surface texture modification can contribute to the adhesive strength between stainless steel and polyphenylene sulfite through on enlarged contact surface area by forming striae, microdimples, and ridges. As compared to the abrasive paper scratching, the stainless steel/plastic joint with laser texture processing exhibits a higher shear strength. [ABSTRACT FROM AUTHOR]

Anthropogenic greenhouse gas emissions are dramatically influencing the environment, and research is strongly committed in proposing alternatives, mainly based on renewable energy sources [[1]]. The papers received and the interaction with the author have encouraged us to propose a new Special Issue titled: "Frontier Trends of Renewable Energy Production and Storage Technologies". This new Special Issue is looking for contributions on these topics, and MDPI and the editors of the journal I Applied Sciences i are delighted to have the privilege of publishing this Special Issue. [Extracted from the article]

This paper presents research on the impact of the material microstructure on the performance of Molten Carbonate Fuel Cells (MCFC). The study is motivated by the need to increase the operation time of MCFC stacks. As the MCFC stacks are mainly composed of porous materials, the paper shows the impact of the porosity on both fuel cell performance and degradation rate. The study is based on the mathematical model, validated through experiments with varying microstructure parameters, achieving an overall relative error of 8%. The study evaluated the performance of MCFC using anodes with different porosity and found that increasing anode porosity from 40% to 70% led to a nearly two-fold increase in maximum power density. However, from both the degradation test and polarization curves, the optimal level of porosity for the anode is around 55%. The porosity level at 55% ensures the highest catalytic surface of the electrodes and is a compromise between the mechanical properties of the electrode and its electrochemical properties. • New approach of 0D model of MCFC including materials microstructure influence is proposed. • The new model is prepared in MS Excel and Aspen HYSYS environments. • Experimental investigation for materials with predefined microstructire parameters was performed for model validation. • Variant analysis is presented for different porosity, tortuosity and constrictivity of MCFC anode. • An optimal scenario is suggested based on modleing results. [ABSTRACT FROM AUTHOR]

The Li2CO3--Na2CO3--K2CO3 carbonate system exhibits superior sulfur interception capacity and thermodynamic stability in the molten salt oxidation (MSO) of cation exchange resins (CERs) with high sulfur content. However, the spent salt from the MSO process cannot be reused to reduce the operating cost and further improve the reduction ratio. Therefore, the optimal oxygen equivalent for treatment is obtained by thermodynamic equilibrium analysis of the MSO process of CERs as 1.08 multiples of the theoretical oxygen demand and the corresponding approximate chemical formula in this work. The results of the equilibrium analysis are used as the basis to propose a replenishment cycle for the MSO process (MSO-RC), which replenishes the consumed carbonate to restore the SO2 adsorption capacity and treatment capacity of the spent salt. During the experiments, the oxidation efficiencies of MSO-RC are higher than 99%, and the volume reduction ratio is improved by 12% compared with the traditional MSO. In addition, the MSO-RC maintains sulfur interception rates above 80% across multiple cycles and preserves over 94.7% Li2CO3 by adding cost-effective Na2CO3 and K2CO3 into the molten salt system. The MSO-RC process significantly improves the efficiency of process operation with lower operational costs. [ABSTRACT FROM AUTHOR]

Hybrid fuel cell/gas turbine systems provide an efficient means of producing electricity from fossil fuels with ultra low emissions. However, there are many significant challenges involved in integrating the fuel cell with the gas turbine and other components of this type of system. The fuel cell and the gas turbine must maintain efficient operation and electricity production while protecting equipment during perturbations that may occur when the system is connected to the utility grid or in stand-alone mode. This paper presents recent dynamic simulation results from two laboratories focused on developing tools to aid in the design and dynamic analyses of hybrid fuel cell systems. The simulation results present the response of a carbonate fuel cell/gas turbine, or molten carbonate fuel cell/gas turbine, (MCFC/GT) hybrid system to a load demand perturbation. Initial results suggest that creative control strategies will be needed to ensure a flexible system with wide turndown and robust dynamic operation. Paper No. GT2004-53653,

New energy is the focus of attention all over the world, and research into new energy can inject new vitality into the industrial system. Hydrogen fuel cells are not only environmentally friendly, but also rich in reserves that can be used as a strategic resource for the entire country. The difficulty lies in the safe design of application equipment and the batch generation and storage of hydrogen. In addition, fuel cells have the disadvantage of a slow start-up. Based on the above problems, this paper proposes a hybrid-element method to solve the thermal-mechanical coupling model of fuel cell plate, which can effectively solve the thermal stress change, temperature field distribution and displacement change of the battery plate when working. Firstly, the hybrid-element algorithm is given for 2D plate deformation. Then, the deformation application of a 3D fuel cell plate is given. The 2D numerical results show that the hybrid finite element method (FEM) is more flexible for realizing the flexible combination of sub-mesh and finite element basis functions, and has a better mesh quality compared to the traditional constant strain triangular element (CST) adaptive FEM and quadrilateral isoparametric element (Q4) adaptive FEM. This method achieves a balance between numerical accuracy and solving efficiency for the multi-porous elastic plate. In addition, a deformation control formula is given which can display the displacement deformation and stress merge to same graph, since it is convenient to quickly compare the regions where the displacement and stress extremum appear. In short, the hybrid finite element method proposed in this paper has good mesh evaluation results, and when the number of discrete elements is equivalent, the hybrid element converges faster and the solution efficiency is higher. This paper also provides a good numerical theory and simulation reference for industrial mechanics and new energy applications. [ABSTRACT FROM AUTHOR]

Nowadays, the power demand is increasing day by day due to the growth of the population and industries. The conventional power plant alone is incompetent to meet the consumer demand due to environmental concerns. In this present situation, the essential thing is to be find an alternate way to meet the consumer demand. In present days most of the developed countries concentrate to develop alternative resources and invest huge money for its research and development activities. Most renewable energy sources are naturally friendly sources such as wind, solar, fuel cell, and hydro/water sources. The results of power generation using renewable energy sources only depend on the availability of the resources. The availability of renewable energy sources throughout the day is variable due to fluctuations in the natural resources. This research work discusses two major renewable energy power generating sources: photovoltaic (PV) cell and fuel cell. Both of them provide foundations for power generation, so they are very popular because of their impressive performance mechanisms. The mentioned renewable energy-based power generating systems are static devices, so the power losses are generally ignorable as compared to line losses in the main grid. The PV and fuel cell (FC) power systems need a controller for maximum power generation during fluctuations in the input resources. Based on the investigation report, an algorithm is proposed for an advanced maximum power point tracking (MPPT) controller. This paper proposes a deep neural network- (DNN-) based MPPT algorithm, which has been simulated using MATLAB both for PV and for FC. The main purpose behind this paper has been to develop the latest DNN controller for improving the output power quality that is generated using a hybrid PV and fuel cell system. After developing and simulating the proposed system, we performed the analysis in different possible operating conditions. Finally, we evaluated the simulation outcomes based on IEEE 1547 and 519 standards to prove the system's effectiveness. [ABSTRACT FROM AUTHOR]

Membrane computing is a branch of natural computing which has been extended to solve various optimization problems. A hybrid mode membrane-computing-based algorithm (HMMCA) is proposed in this paper to solve complex unconstrained optimization problems with continuous variables. The algorithmic framework of HMMCA translates from its distributed cell-like membrane structure and communication rule. A non-deterministic evolutionary programming method and two computational rules are applied to enhance the computational performance. In a numerical simulation, 12 benchmark test functions with different variables are used to verify the algorithmic performance. The test results and comparison with three other algorithms illustrate its effectiveness and superiority. Moreover, a case study on a proton exchange membrane fuel cell (PEMFC) system parameter optimization problem is applied to validate its practicability. The results of the simulation and comparison with seven other algorithms demonstrate its practicability. [ABSTRACT FROM AUTHOR]

The combination of transportation electrification and clean energy in the shipping industry has been a hot topic, and related applications of hybrid all-electric ships (AESs) have emerged recently. However, it has been found that ship efficiency will be negatively impacted by improper component size and operation strategy. Therefore, the bilevel optimal sizing and operation method for the fuel cell/battery hybrid AES is proposed in this paper. This method optimizes the sizing of the AES while considering joint optimal energy management and voyage scheduling. The sizing problem is formulated at the upper level, and the joint scheduling problem is described at the lower level. Then, multiple cases are simulated to verify the effectiveness of the proposed method on a passenger ferry, and the results show that a 5.3% fuel saving and 5.2% total cost reduction can be achieved. Correspondingly, the ship's energy efficiency is improved. This approach also can be used in similar vessels to enhance their overall performance and sustainability. [ABSTRACT FROM AUTHOR]

The paper presents a simulation investigation of using a molten carbonate fuel cell (MCFC) combined with exhaust gas recirculation (EGR) or selective exhaust gas recirculation (SEGR) to reduce CO2 emission from the gas turbine in order to cope with climate change problem. EGR or SEGR can be used to concentrate the low-concentration CO2 in gas turbine exhausts. The CO2 concentration is then raised further by adding gas turbine exhaust to the MCFC's cathode. The suggested gas–steam combined cycle system paired with MCFC and CO2 collection without EGR is contrasted with two novel gas–steam combined cycle systems integrated with MCFC, EGR, or SEGR with CO2 capture (the reference system). The thermal efficiency of the gas–steam combined cycle systems' integrated MCFC, EGR and SEGR with CO2 collection is 56.08%, which is 1.3% higher than the reference system. The cost of CO2 avoided in the new system with SEGR will be equal to that of the system with the MEA technique for CO2 capture if the MCFC cost is reduced to 904.4 USD/m2. [ABSTRACT FROM AUTHOR]

The paper presents an investigation into the three cathode layers for the Molten Carbonate Fuel Cell that were obtained by using printing techniques on various surfaces. The main differences during the manufacturing process were the substrates used when printing the layers: glass and two different sorts of paper. The cathodes were investigated at the theoretical and experimental level. To identify the influence of the substrate used we built a mathematical model of the fuel cell, in which the influence is expressed by the conductivity of the layer. The paper demonstrates the possibility of using printing techniques to manufacture Molten Carbonate Fuel Cell layers. [ABSTRACT FROM AUTHOR]

Among the global carbon emissions in different fields, the carbon emissions in the transportation sector account for more than 1/4. Only the development of passenger car technology makes it difficult to achieve the climate goals. E-bike is considered to be one of the effective solutions. Hydrogen energy, as one of the representatives of new energy, has the advantages of cleanliness, high efficiency, and high energy density. Therefore, in this paper, a long-range hydrogen-electric hybrid bike and its energy management strategy are designed to achieve optimal performance. Herein, two energy management strategies, including the threshold-based and fuzzy logic optimized threshold-based strategy, are designed and compared by evaluating the parameters of equivalent hydrogen consumption, state of charge fluctuation, and the final state of the control system. The results show that with an initial SOC of 50% for Li-ion battery, the fuzzy logic optimized threshold-based strategy reduces equivalent hydrogen consumption by up to 16% compared to the threshold-based strategy. Besides, the fluctuation of the Li-ion battery's state of charge could be reduced by up to 54.7%, indicating that the fuzzy logic optimized threshold-based strategy is a promising energy management strategy for fuel cell hybrid E-bike. [Display omitted] • A long-range hydrogen-electric hybrid E-bike with metal hydride hydrogen storage is designed. • A fuzzy logic optimized threshold-based energy management strategy (EMS) is proposed. • Li-ion battery SOC fluctuations could be reduced by up to 54.7% via fuzzy logic optimized EMS. • Fuzzy logic optimized EMS shows self-adaptability and economic H 2 consumption for hybrid E-bike. [ABSTRACT FROM AUTHOR]

The hybrid microgrid system (HMS) can offer a cost-effective system for isolated areas by optimizing energy sources. This paper presents a design approach for a wind turbine (WT)/hydrogen HMS with eight alternative small horizontal-axis WTs and arrives at a conclusion based on the total annual cost (TAC), cost of energy (COE), and the loss of power supply possibility throughout the project's life cycle. The effect of adding solar panels to the HMS is investigated in different scenarios. The modified bio-inspired optimization algorithm with high efficiency is used, and its results are validated using an original particle swarm optimization in different unavailability levels. Owing to a sensitivity analysis that utilized the wind speed, load demand, and interest rate, the potential of the proposed algorithm to achieve the optimal off-grid HMS design was highlighted. Among the investigated systems (more than 16 systems), the Winds WT/hydrogen energy/solar configuration with $11,952 TAC and 0.3458$/kWh COE has the minimum cost while setting the unavailability level to 2%. In addition, the adding of solar panels, variation of small WT models, wind speed, load demand, and interest rate levels have a significant impact on COE value and number of components. • A design approach for a wind/hydrogen system with various small horizontal-axis WT is proposed. • The effect of adding solar panel to the hybrid system is investigated in different scenarios. • The modified bio-inspired optimization algorithm with high efficiency is proposed. • The algorithm results are validated using an original PSO in different reliability level. • Sensitivity analysis to account for uncertainties in the optimal system is investigated. [ABSTRACT FROM AUTHOR]

Cationic exchange resins are used in nuclear power circuits to remove the nuclide ions to maintain the safe and efficient operation of nuclear power plants. Meanwhile, the production of spent resins is expanding significantly due to the rapid technological advancements in the nuclear industry, causing the study of resin treatment to be of great significance. This study reveals the catalytic behavior of Mn from cation exchange resins during molten salt oxidation. Mn has many isotopic ions and a catalytic effect on the treatment process. Kinetic analysis reveals that the introduction of Mn decreases the activation energy of the styrene–divinylbenzene skeleton from 48.164 kJ mol−1 to 41.696 kJ mol−1 and decreases the degradation temperature of the resin by 78 °C. Compared to the original resin, the destruction and removal efficiency of Mn-doped cation exchange resin increased from 75.07% to 85.28% during molten salt oxidation at 650 °C. According to the scanning electron microscope analysis and characterization studies, Mn promotes a 55.71% reduction in the average particle diameter of resin structural fragments. Fourier-transform infrared spectroscopy analysis of the resin residues demonstrates that Mn doping influences the catalytic decomposition of –SO2– and S–O within sulfonic acid groups. This catalytic effect induces destabilization and subsequent ring-opening of the benzene ring. These results imply that Mn doping can facilitate molten carbonate oxidation destruction of cation exchange resins. The X-ray diffraction analysis of waste salt reveals that with increasing oxidation time, the transformation of Mn proceeds as (Mn2O6)6− → (MnO3)2− → (MnO2)− at 750 °C. [ABSTRACT FROM AUTHOR]

Laser based directed energy deposition (L-DED) is a promising type of additive manufacturing technology. The non-destructive testing technology for the quality monitoring of L-DED processed parts is becoming more and more demanding in terms of accuracy, real-time, and ease of operation. This paper introduces a new image recognition system based on a deep convolutional neural network, which uses multiple lightweight architectures to reduce detection time. In order to eliminate the interference better, it improves the penalty function, which effectively improves the accuracy. Judging from the detection results of the data set, the accuracy of the model training reaches 94.71%, which achieves a very good image segmentation effect and solves the technical problem of in-situ monitoring of the L-DED process. This system realizes the positioning of the spatters for the first time, and at the same time, the number of spatters and area of molten pool are correlated to the laser scanning speed and the laser power. [ABSTRACT FROM AUTHOR]

Durability and reliability are the major bottlenecks of the proton-exchange-membrane fuel cell (PEMFC) for large-scale commercial deployment. With the help of prognostic approaches, we can reduce its maintenance cost and maximize its lifetime. This paper proposes a hybrid prognostic method for PEMFCs based on a decomposition forecasting framework. Firstly, the original voltage data is decomposed into the calendar aging part and the reversible aging part based on locally weighted regression (LOESS). Then, we apply an adaptive extended Kalman filter (AEKF) and long short-term memory (LSTM) neural network to predict those two components, respectively. Three-dimensional aging factors are introduced in the physical aging model to capture the overall aging trend better. We utilize the automatic machine-learning method based on the genetic algorithm to train the LSTM model more efficiently and improve prediction accuracy. The aging voltage is derived from the sum of the two predicted voltage components, and we can further realize the remaining useful life estimation. Experimental results show that the proposed hybrid prognostic method can realize an accurate long-term voltage-degradation prediction and outperform the single model-based method or data-based method. [ABSTRACT FROM AUTHOR]

In this paper, an optimization approach is formulated to determine the optimal power split in a proton exchange membrane fuel cell-battery-hybrid energy system (PEMFC-battery-HES) to meet the dynamically varying locomotive power demand. The optimization approach aims to determine the power references for the PEMFC at each loading point of the locomotive power demand with the objective function of minimization of the PEMFC fuel consumption over the driving period. The constraints of optimization include the instantaneous power balance between the source and the load, the limits on the variation of battery state-of-charge and PEMFC output power, and the durability constraints in terms of the maximum rate of change in PEMFC output power, and maximum allowable degradation in the state-of-health of the battery over a specified planning period. The optimization model is solved using the CONOPT solver of General Algebraic Modeling System. The performance of the proposed energy management optimization approach is tested through comparison with some of the already available approaches for different drive cycle scenarios. Simulation results confirm that the proposed approach results in 1–5.5% reduction in the PEMFC fuel consumption with optimum utilization of the capacities of the energy sources. [ABSTRACT FROM AUTHOR]

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The objective of this paper is to study the impact of combining hydrogen fuel cells with lithium-ion batteries through an ideal power-sharing architecture to mitigate the poor range and endurance of battery powered electric vertical takeoff and landing (eVTOL) aircraft. The benefits of combining the two sources is first illustrated by a conceptual sizing of an electric tiltrotor for an urban air taxi mission of 75 mi cruise and 5 min hover. It is shown that an aircraft of 5000-6000 lb gross weight can carry a practical payload of 500 lb (two to three seats) with present levels of battery specific energy (150Wh/kg) if only a battery-fuel cell hybrid power plant is used, combined in an ideal power-sharing manner, as long as high burst C-rate batteries are available (4-10 C). A power plant using batteries alone can carry less than half the payload; use of fuel cells alone cannot lift off the ground. Next, the operation of such a system is demonstrated using systematic hardware testing. The concepts of unregulated and regulated power-sharing architectures are described. A regulated architecture that can implement ideal power sharing is built up in a step-by-step manner. It is found only two switches and three DC-to-DC converters are necessary, and if placed appropriately, are sufficient to achieve the desired power flow. Finally, a simple power system model is developed, validated with test data and used to gain fundamental understanding of power sharing. [ABSTRACT FROM AUTHOR]

This paper performs a technoeconomic comparison of two hybrid renewable energy supplies (HRES) for a specific location in Ghana and suggests the optimal solution in terms of cost, energy generation capacity, and emissions. The two HRES considered in this paper were wind/hydrogen/fuel-cell and wind/battery storage, respectively. The necessity of this study was derived from the rise and expansion of hybrid renewable energy supply in a decentralised network. The readiness to embrace these new technologies is apparently high, but the best combination for a selected location that brings optimum benefits is not obvious and demands serious technical knowledge of their technical and economic models. In the methodology, an analytical model of energy generation by the various RE sources was first established, and data were collected about a rural-urban community in Doderkope, Ghana, to test the models. HOMER software was used to design the two hybrid systems based on the same load profiles, and results were compared. It turns out that the HRES 1 (wind/hydrogen/fuel-cell) had the lowest net present cost (NPC) and levelized cost of electricity (COE) over the project life span of 25 years. The energy reserve with the HRES 2 (wind/battery storage) was huge compared to that with the HRES 1, about 270% bigger. Furthermore, with respect to the emissions, the HRES 2 was environmentally friendlier than the HRES 1. Even though the battery storage seems to be more cost-effective than the hydrogen fuel-cell technology, the latter presents some merits regarding system capacity and emission that deserve greater attention as the world looks into more sustainable energy storage systems. [ABSTRACT FROM AUTHOR]

Solar energy has attracted the attention of researchers around the world due to its advantages. However, photovoltaic (PV) panels still have not attained the desired efficiency and economic mature. PV tracking techniques can play a vital role in improving the performance of the PV system. The aim of this paper is to evaluate and compare the technical and economic performance of grid-connected hybrid energy systems including PV and fuel cells (FC) by applying major types of PV tracking technique. The topology and design principles and technical description of hybrid system components are proposed in this paper. Moreover, this paper also introduces economic criteria, which are used to evaluate the economy of different PV tracking techniques and seek the optimal configuration of system components. In the case study, the results show that the vertical single axis tracker was ranked 1st in terms of highest PV generation, penetration of renewable energy to the grid, lowest CO2 emission, highest energy sold to the grid and lowest purchased, and lowest net present cost (NPC) and levelized cost of energy (LCOE). The study found that the optimal design of a grid-connected hybrid energy system (PV-FC) was by using a vertical single axis tracker which has the lowest NPC, LCOE. [ABSTRACT FROM AUTHOR]

The growth in the use of unmanned aerial vehicles (UAVs) has created an increasing demand for energy‐efficient and green power systems. In this paper, we have evaluated energy management strategies (EMSs) and system optimization design methodologies for fuel cell/battery‐powered hybrid UAVs (HUAVs). EMSs aimed at the optimization of flight endurance and fuel cell durability were proposed based on fuzzy logic, dynamic programming, equivalent consumption minimization, and Pontryagin's minimum principle (PMP). System optimization design methodologies, including static design and synergistic sizing optimization design, were also devised. The synergistic sizing optimization was based on multiobjective optimization, while optimization of the EMS used a non‐dominated sorting genetic algorithm. The effectiveness of the proposed EMSs and optimization design were then validated by simulation. Results showed that the proposed EMSs have both long flight time and good fuel cell durability, with the improved PMP prolonging the fight endurance by 4.64% and reducing the mean current of the fuel cell by 16.1% compared with fuzzy logic. Substantial improvements were obtained by using sizing optimization, and parameter sensitivity was addressed. The findings of this study can aid in the future development of fuel cell‐powered UAVs. [ABSTRACT FROM AUTHOR]

This paper describes the implementation of a hydrogen-based system for an autonomous surface vehicle in an effort to reduce environmental impact and increase driving range. In a suitable computational environment, the dynamic electrical model of the entire hybrid powertrain, consisting of a proton exchange membrane fuel cell, a hydrogen metal hydride storage system, a lithium battery, two brushless DC motors, and two control subsystems, is implemented. The developed calculation tool is used to perform the dynamic analysis of the hybrid propulsion system during four different operating journeys, investigating the performance achieved to examine the obtained performance, determine the feasibility of the work runs and highlight the critical points. During the trips, the engine shows fluctuating performance trends while the energy consumption reaches 1087 Wh for the fuel cell (corresponding to 71 g of hydrogen) and 370 Wh for the battery, consuming almost all the energy stored on board. [ABSTRACT FROM AUTHOR]

Hybrid green energy system, consisting of photovoltaic (PV), fuel cell and battery, receives wide attention because of its autonomy, flexibility and promising potential in accelerating the development of carbon neutrality in the field of power generation. However, the efficient power dispatching of the hybrid energy system is challenging due to the inevitable uncertainties of the solar energy. To this end, stochastic dynamic programming (SDP) is used in this paper to find the optimal solution to minimize the total fuel consumption during a 72-hour operating cycle, with constraints on the magnitude and rate of the fuel cell and battery operation, in which the stochastic characteristics of the solar power are described by Markov chain. The influence of sampling time and number of states on the solar prediction accuracy is discussed. For comparison, the traditional rule-based algorithm and dynamic programming (DP) algorithms are also utilized to describe and solve the power distribution problem, corresponding to different decision results in terms of how to distribute the energy flow for each time period. Numerical optimization results within the 72-hour period demonstrate that, the SDP has a 20.61% economy and 66.34% battery SOC improvement than that of rule-based algorithm, and in most uncertain cases, the SDP produces superior economic performance than those of both the rule-based algorithm and DP, benefited from the inclusion of the solar power probabilities into the optimization framework. The results of this paper lay a solid foundation for the efficient energy management of the hydrogen and solar hybrid energy system. The stochastic dynamic programming is used in this paper to deal with the uncertainties in solar energy and find the optimal energy scheduling of a hybrid fuel cell/PV/battery system. Numerical optimization results demonstrate that, in most uncertain cases, stochastic dynamic programming produces superior economic performance than those of both the rule-based and dynamic programming algorithm. The results lay a solid foundation for the efficient energy management of the hydrogen and solar hybrid energy system. [Display omitted] [ABSTRACT FROM AUTHOR]

Developing an energy management strategy (EMS) is an important requirement to satisfy the load power demand for a proton-exchange membrane fuel cell (PEMFC) hybrid system under different working conditions. For this objective, this paper proposes an EMS to control the power distribution between the PEMFC, battery (BAT), and supercapacitor (SC) and regulate the DC bus voltage for matching the load power demand. In this strategy, fuzzy logic rules (FLRs) and low-pass filters (LPFs) are utilized to determine the reference currents for energy sources based on their dynamic response. In addition, current and voltage control loops are designed to provide the appropriate gains for compensators that can maintain a stable voltage on the DC bus. Finally, simulations are conducted in the MATLAB/Simulink environment to validate and compare the effectiveness of the proposed strategy with others. The simulation results present that the proposed EMS achieves the highest distributed power accuracy with an error of (− 2.1 → 2.6) W, while reducing the DC bus voltage ripple by 1% under various load working conditions in comparison to the other approaches. [ABSTRACT FROM AUTHOR]

During laser-metal inert gas (MIG) hybrid welding, a large amount of welding status information is generated in droplet transfer, keyhole and molten pool. In this paper, austenitic stainless steel was adopted as an experimental object, with a dual high-speed camera system used to obtain real-time images of droplet transfer, keyhole and molten pool in a laser-MIG hybrid welding process. The changing regulation of a keyhole in three different penetration states (i.e., non-penetration, partial penetration and normal penetration) was analyzed by extracting the morphological characteristics of a keyhole shape, and combining the droplet transition information and the shape of the weld pool. Experimental results show that the proposed method could effectively reflect the variation characteristics of the keyhole, and the correlation among the keyhole characteristics, the droplet transfer information, the weld pool shape and the welding status, and provide a new perspective for online detection of the laser-MIG welding quality. [ABSTRACT FROM AUTHOR]

This paper proposes an optimized energy management strategy (EMS) for hybrid electric fuel cell/battery-based drones focusing on fuel economy while extending sources lifespans in persistent missions. An off-the-shelf drone fed by a 650 $\mathrm{W}$ fuel cell is selected as a case study, where the power splitting is conventionally managed by a simple rule-based method. Then, a multi-objective genetic algorithm is used to optimize the proposed EMS parameters considering three scenarios regarding battery state of charge, namely charge sustaining, depleting, and increasing. Therefore, advantages of rule-based strategy and genetic algorithm are combined in an online EMS to fit on drone applications. Extensive simulation results demonstrate that the proposed approach allows power sources to operate within their rated area, prolonging their service life, and leading to 5.1% of fuel consumption reduction. Thus, the autonomy will be increased depending on the carried hydrogen quantity, and the world record can be extended by about 37 min. It may also lead to benefit in the operating cost achieving 1450€ during one fuel cell stack lifecycle. In fleet tasks, the benefit can be further multiplied. [ABSTRACT FROM AUTHOR]

Summary: This paper proposes a multiobjective optimization for fuel consumption (including fossil fuel and hydrogen) and polluted gas emission in a hybrid electric aircraft. The proposed convex multiobjective model aims at minimizing the total fuel consumption during the entire flight mission as well as the corresponding fuel cell size. The problem is formulated as mixed‐integer nonlinear programming using the Karush–Kuhn–Tucker optimality condition and solved by GAMS. Solving the proposed computationally efficient problem showed that, compared with the conventional hybrid‐electric aircraft, the optimum fuel cell power can improve the aircraft performance in terms of fuel consumption and polluted gas emission. [ABSTRACT FROM AUTHOR]

The paper concerns the design analysis of a hybrid gas turbine power plant with a fuel cell (stack). The aim of this work was to find the most favourable variant of the medium capacity (approximately 10 MW) hybrid system. In the article, computational analysis of two variants of such a system was carried out. The analysis made it possible to calculate the capacity, efficiency of both variants and other parameters like the flue gas temperature. The paper shows that such hybrid cycles can theoretically achieve extremely high efficiency over 60%. The most favourable one was selected for further detailed thermodynamic and flow calculations. As part of this calculation, a multi-stage axial compressor, axial turbine, fuel cell (stack) and regenerative heat exchanger were designed. Then an analysis of the profitability of the installation was carried out, which showed that the current state of development of this technology and its cost make the project unprofitable. For several years, however, tendencies of decreasing prices of fuel cells have been observed, which allows the conclusion that hybrid systems will start to be created. This may apply to both stationary and marine applications. Hybrid solutions related to electrical power transmission, including fuel cells, are real and very promising for smaller car ferries and shorter ferry routes. [ABSTRACT FROM AUTHOR]

Given the current maturity of hydrogen technologies, accurate and computationally efficient numerical models are crucial for improving their understanding and development. Traditional models are either computationally prohibitive or lack the capacity to assess the spatial distribution of critical variables. The present paper suggests a hybrid numerical model for Fuel Cells (FCs) and electrolysers, articulating the coupling between a 1D analytical model and a Computational Fluid Dynamics (CFD) model via a nonlinear regression. Results present an initial validation of the 1D analytical model and the CFD model, and, once the validation is proven successful, the hybrid model is evaluated with a relatively long and highly varying loading profile that covers a wide range of the potential operational points of a FC. The hybrid model shows promising results, showing fidelity levels similar to CFD models, including the capacity to assess the spatial distribution, and a low computational cost. Hence, this hybrid model is demonstrated to be an attractive tool for the design of FCs and electrolysers, optimisation of thermal management and control strategies, degradation analysis, and techno-economic analysis. [ABSTRACT FROM AUTHOR]

The aim of the paper is to examine the performance of molten carbonate fuel cell, which is supplied with a raw bioethanol, i.e. bioethanol which origins directly from fruit fermentation, without pre-treatment of fermentation products. The composition of raw bioethanol was precisely determined and then the impact of raw bioethanol on the degradation of molten carbonate fuel cells was examined. Steam to carbon ratio of the biofuel has been determined as 5.7 (in comparison to stoichiometry of reaction) which allowed for estimation of hydrogen production during steam reforming process taking place in the anode channel. The results in the form of current-voltage curve was obtained and compared with the same fuel cell fed with pure hydrogen, while the amount of hydrogen was defined as identical with the one after steam reforming of biofuel taking place in the nickel anode channel. Relevant literature studies were focused on the purified fuel or examination of the impact of individual components. Our study proved carbon deposition is not a problem, however solid particles contamination in fermentation product makes it impossible to use fuel cell fueled with fermentation product for longer periods, and prior to supplying fuel cell the bioethanol purification is required. A raw biofuel with its impurities did not have any impact on the anode and current collector surface from physical point of view, but Electrochemical Impedance Spectroscopy analysis shows visible increase of ohmic loses. • Homemade first generation bioethanol composition have been examined. • Manufactured bioethanol has been delivered directly to the MCFC anode without purification. • Performance of MCFC fueled with impure bioethanol has been investigated. • Effect of steam reforming for hydrogen generation and steam to carbon ratio were evaluated. • Pollution on the anode after cell operation was investigated with SEM and EIS. [ABSTRACT FROM AUTHOR]

This paper presents the results of research into improving the ionic conductivity of Molten Carbonate Fuel Cell by modifying the matrix material. So far, we have succeeded in using materials such as YSZ and SDC, but we are now trying to use powders based on Ba Na and TiO 2. These materials are characterized by their oxygen ion conductivity at elevated temperatures. A matrix of these materials was produced and used to build MCFCs. Based on the experiments carried out and the mathematical model of the fuel cell, the contribution of the oxygen ion conductivity to the total ionic conductivity was determined. • Research on oxygen ion conduction materials was performed. • BNT material has best oxygen ion conductivity parameters and was chosen for experiments. • New matrix made of BNT was manufactured. • Composite Li/K and BNT membrane was investigated under EIS and in fuel cell. • Model including ionic conductivity and tortuosity is presented and validated. [ABSTRACT FROM AUTHOR]

Degradation prediction of proton exchange membrane fuel cell (PEMFC) is critical for optimizing fuel cell operation and extending its lifetime, facilitating its large-scale commercialization. This paper proposed a hybrid method based on the mechanism voltage model and the advantage actor-critic (A2C) algorithm to achieve degradation prediction. A semi-empirical voltage model is established to extract four aging parameters: exchange current density, leakage current density, reaction area, and area-specific resistance. A2C is then applied to predict aging parameters and output voltage under stochastic conditions, precisely characterizing the degradation process. Two sets of ∼1,000h real data from 65 kW PEMFCs on city buses are used for training, validating, and optimizing the proposed model. The results show that the method can accurately predict voltage degradation and efficiently track voltage fluctuations without delay under actual operating conditions. The prediction root mean square errors for the two datasets with a training ratio 0.8 are 0.0095 and 0.0115, respectively, smaller than conventional prediction methods. The hybrid method can provide detailed internal degradation information and has potential for online forecast applications. • Two sets of operating data from commercially operated city buses are employed. • A hybrid model based on advantage actor-critic (A2C) algorithm is developed. • The A2C algorithm is applied to predict extracted aging parameters. • The proposed model can track voltage fluctuations under actual operating conditions. • A grid search algorithm is used to accelerate the model convergence process. [ABSTRACT FROM AUTHOR]

There are complex coupling relationships between flight motion and energy management for hybrid electric fixed wing UAVs with photovoltaic/fuel cell/battery. Aiming at realizing high-energy-efficiency long endurance autonomous flight, this paper proposes a coordinated optimization method of trajectory optimization and energy management for hybrid electric UAVs. Numerical simulation and experiment are carried out. Separated by surplus demand energy except that produced by PV, this method includes an optimal energy flight trajectory optimization layer and an energy management layer. For the former, fuzzy neural network sequential convex optimization (FNNSCP) is proposed to handle the flight trajectory optimization problem for maximizing utilization solar energy. For the latter, an online energy management strategy based on convex quadratic programming MPC (CQPMPC) is proposed to realize the power allocation. Numerical simulation results show that FNNSCP reduced 2% energy requirement compared with Radau pseudo-spectral method (RPM) from flight trajectory optimization level. From energy management level, CQPMPC saves hydrogen consumption by 3.1% and 16.3% compared with nonlinear model predictive control (NMPC) and fuzzy logic state machine (FLSM), respectively. In the experiment, less hydrogen fuel is consumed by proposed method by 5.2% and 15.6% compared with NMPC and FLSM, respectively. Experimental results show that the proposed method has better energy-saving performance and excellent real time performance. It indicates that optimizing flight trajectory and improving energy management efficiency can realize the high-energy-efficiency flight of hybrid electric UAVs. This method is conducive to promoting the application of hydrogen energy in the field of UAVs. [Display omitted] • A coordinated optimization method is proposed for the high-energy-efficiency flight. • Fuzzy neural network adaptive sequential convex optimization method is proposed. • Online energy management strategy with convex quadratic programming MPC is proposed. • The proposed method is verified by simulation and energy management experiment. [ABSTRACT FROM AUTHOR]

The hybrid combination of hydrogen fuel cells (FCs) and batteries has emerged as a promising solution for efficient and eco-friendly power supply in maritime applications. Yet, ensuring high-quality and cost-effective energy supply presents challenges. Addressing these goals requires effective coordination among multiple FC stacks, batteries, and cold-ironing. Although there has been previous work focusing it, the unique maritime load characteristics, variable cruise plans, and diverse fuel cell system architectures introduce additional complexities and therefore worth to be further studied. Motivated by it, a two-layer energy management system (EMS) is presented in this paper to enhance shipping fuel efficiency. The first layer of the EMS, executed offline, optimizes day-ahead power generation plans based on the vessel's next-day cruises. To further enhance the EMS's effectiveness in dynamic real-time situations, the second layer, conducted online, dynamically adjusts power splitting decisions based on the output from the first layer and instantaneous load information. This dual-layer approach optimally exploits the maritime environment and the fuel cell features. The presented method provides valuable utility in the development of control strategies for hybrid powertrains, thereby enabling the optimization of power generation plans and dynamic adjustment of power splitting decisions in response to load variations. Through comprehensive case studies, the effectiveness of the proposed EMS is evaluated, thereby showcasing its ability to improve system performance, enhance fuel efficiency (potential fuel savings of up to 28%), and support sustainable maritime operations. [Display omitted] • Hybrid PEM fuel cell/battery system enables zero-emission shipping. • Two-layer EMS enhances fuel efficiency while satisfying real-time load requirements. • Rotational sequential distribution prevents uneven degradation. • Rotational sequential distribution enhances computational efficiency. [ABSTRACT FROM AUTHOR]

The All-electric ship (AES) concept has revolutionized the maritime sector. Indeed, AES is a promising solution for modern vessels where decreasing emission pollution, suppressing fossil fuel consumption, and making economical operation are its brilliant merits. Fuel cell (FC) technology based on clean hydrogen energy sources can play a significant role in meeting these requirements in the AES platform. Because of the slow transient response of the FC, an energy storage system (ESS) is required to improve AES performance in different operation scenarios. Therefore, optimal sizing of the FC and the ESS and proper design of energy management strategy is a challenging problem. This paper proposes a systematic approach for the optimal design of hybrid FC-ESS of AES power systems. The proposed method is based on an optimization technique to determine the optimal sizing of the FCs and the ESS. Capital investment, fuel consumption, personnel electrical safety, and occupied volume of the AES power system are the main objectives. The FC size, the battery size, the scheduled output power of the FC, and the battery are the decision variables. Genetic Algorithm (GA) is used to solve the optimization problem. To validate the numerical results, the optimization problem is also solved by Mayfly Algorithm (MA) separately. To assess the feasibility of the proposed strategy, the optimal design of hybrid FC-ESS for a vessel is implemented based on the proposed method. The simulation results validate the proposed approach's sufficiency to investigate and optimize the economic, safety, and dimensional aspects of designing the FC ship's IPS. Numerical results are reported for each design aspect. Considering the minor differences of the numerical results obtained by GA and MA, the optimum points are validated by the two techniques. Using the obtained results, various perceptions can be derived from the FC ship's IPS design. For example, the IPS cost in the cases with optimum volume, weight, and safety, has 2.3%, 2.6%, and 7.3% penalties, respectively compared to the case with the minimum cost. • Fuel cell-based electrification of a fishing ship based on practical information. • Systematic approach for optimal power system design of hydrogen-powered ship. • Proposing safety objective function for integrated power system of fuel cell ship. • Fuel cell hybrid IPS optimization based on volume, mass, cost and safety. • Estimation of propulsion power demand based on ship's resistance and speed profile. [ABSTRACT FROM AUTHOR]

This paper reports the performance of a molten carbonate fuel cell (MCFC) fed directly with liquid fuels referenced against results with hydrogen fuel in experiments conducted by the research team. Alcohols have greater energy density than pure hydrogen in normal conditions and, if presented as biofuels, the MCFC can be deemed a renewable energy source. For evaluation purposes various alcohols occurring in standard conditions in the liquid state were used for electricity generation in the MCFC: methanol, ethanol, propanol, butanol and glycerol. Since these alcohols can be subjected to steam reforming when mixed with water in specific ratios, they can be delivered directly in the liquid state to the fuel cell, where hydrogen is released and used to produce electricity and heat. The alcohols were mixed with water in ratios of 1:2, 1:3, 1:4. The results were compared to the MCFC fed with pure hydrogen as a fuel. In terms of power referenced to hydrogen (100%), the maximums achieved were 78% for butanol, 80% for glycerol, 83% for propanol, 86% for ethanol and 93% for methanol in comparison to the same amount of hydrogen delivered to the fuel cell in ideal steam reforming situation. Threats such as carbon deposition on the fuel cell surface were also evaluated. • MCFC fed directly with various mixtures of alcohols and water have been studied. • The steam reforming of mixtures of alcohols and water generates energy. • Temperature and anode material provide the necessary conditions for steam reforming. • Maximum power compared to hydrogen fuel for various fuels ranges between 78 and 93%. • Carbon deposition in the anode channel of commercial units can be a problem. [ABSTRACT FROM AUTHOR]

Owing to the significant number of hybrid generation systems (HGSs) containing various energy sources, coordination between these sources plays a vital role in preserving frequency stability. In this paper, an adaptive coordination control strategy for renewable energy sources (RESs), an aqua electrolyzer (AE) for hydrogen production, and a fuel cell (FC)-based energy storage system (ESS) is proposed to enhance the frequency stability of an HGS. In the proposed system, the excess energy from RESs is used to power electrolysis via an AE for hydrogen energy storage in FCs. The proposed method is based on a proportional-integral (PI) controller, which is optimally designed using a grey wolf optimization (GWO) algorithm to estimate the surplus energy from RESs (i.e., a proportion of total power generation of RESs: Kn). The studied HGS contains various types of generation systems including a diesel generator, wind turbines, photovoltaic (PV) systems, AE with FCs, and ESSs (e.g., battery and flywheel). The proposed method varies Kn with varying frequency deviation values to obtain the best benefits from RESs, while damping the frequency fluctuations. The proposed method is validated by considering different loading conditions and comparing with other existing studies that consider Kn as a constant value. The simulation results demonstrate that the proposed method, which changes Kn value and subsequently stores the power extracted from the RESs in hydrogen energy storage according to frequency deviation changes, performs better than those that use constant Kn. The statistical analysis for frequency deviation of HGS with the proposed method has the best values and achieves large improvements for minimum, maximum, difference between maximum and minimum, mean, and standard deviation compared to the existing method. [ABSTRACT FROM AUTHOR]

The use of multiple low-power fuel cells (FCs), instead of a high-power one, in the powertrain of a FC-hybrid electric vehicle (FC-HEV) has recently received considerable attention. This is mainly due to the fact that this configuration can lead to higher efficiency, durability, and reliability. However, the added degrees of freedom require an advanced multi-agent energy management strategy (EMS) for an effective power distribution among power sources. This paper puts forward an EMS based on game theory (GT) for a multi-stack FC-HEV with three FCs and a battery pack. GT is a well-approved method for characterizing the interactions in multi-agent systems. Unlike the other strategies, the proposed EMS is equipped with an online identification system to constantly update the time-varying characteristics of the power sources. The performance of the suggested strategy is investigated through two case studies. Firstly, a comparative study with two other EMSs, dynamic programming (offline), and a competent rule-based strategy (online), is conducted to realize the capability of GT. Secondly, to justify the necessity of online system identification, the degradation effect of each power source on the EMS performance is examined. The carried-out studies show that the total cost (hydrogen consumption and degradation) of the proposed strategy is almost 6% better than the rule-based EMS while keeping a reasonable difference with dynamic programming. Moreover, health unawareness of power sources can increase the hydrogen consumption up to 7% in the studied system. [ABSTRACT FROM AUTHOR]

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This paper presents the development of a global and integrated sizing approach under different performance indexes applied to fuel cell/battery hybrid power systems. The strong coupling between the hardware sizing process and the system supervision (energy management strategy EMS) makes it hard for the design to consider all the possibilities, and today's methodologies are mostly experience-based approaches that are impervious to technological disruption. With a smart design approach, new technologies are easier to consider, and this approach facilitates the use of new technologies for transport applications with a decision help tool. An automotive application with a hybrid fuel cell (PEMFC)/battery (Li-Ion) is considered to develop this approach. The proposed approach is based on imbricated optimization loops and considers multiple criteria such as the fuel consumption, reliability, and volume of the architecture, in keeping with industry expectations to allow a good trade-off between different performance indexes and explore their design options. This constitutes a low computational time and a very effective support tool that allows limited overconsumption and lifetime reduction for designed architecture in extreme and non-optimal use. We obtain, thanks to this work, a pre-design tool that helps to realize the first conception choice. [ABSTRACT FROM AUTHOR]

Due to a high conductivity of about 0.1 S·cm−1, Li-Na-K carbonate eutectic and Sm-doped ceria composite material is a good electrolyte candidate for hybrid fuel cells operating between 500 °C and 600 °C. The present paper aims at a deeper understanding of the species and mechanisms involved in the ionic transport through impedance spectroscopy and thermal analyses, in oxidizing and reducing atmospheres, wet and dry, and during two heating/cooling cycles. Complementary structural analyses of post-mortem phases allowed us to evidence the irreversible partial transformation of molten carbonates into hydrogenated species, when water and/or hydrogen are added in the surrounding atmospheres. Furthermore, this modification was avoided by adding CO2 in anodic and/or cathodic compartments. Finally, a mechanistic model of such composite electrical behavior is suggested, according to the surrounding atmospheres used. It leads to the conclusions that cells based on this kind of electrolyte would preferably operate in molten carbonate fuel cell conditions, than in solid oxide fuel cell conditions, and confirms the name of "Hybrid Fuel Cells" instead of Intermediate Temperature (or even Low Temperature) Solid Oxide Fuel Cells. [ABSTRACT FROM AUTHOR]

Hybrid fuel cell/gas turbine systems provide an efficient means of producing electricity from fossil fuels with ultra low emissions. However, there are many significant challenges involved in integrating the fuel cell with the gas turbine and other components of this type of system. The fuel cell and the gas turbine must maintain efficient operation and electricity production while protecting equipment during perturbations that may occur when the system is connected to the utility grid or in stand-alone mode. This paper presents recent dynamic simulation results from two laboratories focused on developing tools to aid in the design and dynamic analyses of hybrid fuel cell systems. The simulation results present the response of a carbonate fuel cell/gas turbine, or molten carbonate fuel cell/gas turbine, (MCFC/GT) hybrid system to a load demand perturbation. Initial results suggest that creative control strategies will be needed to ensure a flexible system with wide turndown and robust dynamic operation. Paper No. GT2004-53653,

The present review paper highlights recent progress in the processing of potential municipal solid waste (MSW) derived fuels. These wastes come from the sieved fraction (∅ < 40 mm), which, after sorting, can differ in biodegradable fraction content ranging from 5-60%. The fuels obtained from these wastes possess volumetric energy densities in the range of 15.6-26.8 MJL-1 and are composed mainly of methanol, ethanol, butanol, and carboxylic acids. Although these waste streams are a cheap and abundant source (and decrease the fraction going to landfills), syngas produced from MSW contains various impurities such as organic compounds, nitrogen oxides, sulfur, and chlorine components. These limit its use for advanced electricity generation especially for heat and power generation units based on high temperature fuel cells such as solid oxide fuel cells (SOFC) or molten carbonate fuel cells (MCFC). In this paper, we review recent research developments in the continuous MSW processing for syngas production specifically concentrating on dry reforming and the catalytic sorbent effects on effluent and process efficiency. A particular emphasis is placed on waste derived biofuels, which are currently a primary candidate for a sustainable biofuel of tomorrow, catalysts/catalytic sorbents with decreased amounts of noble metals, their long term activity, and poison resistance, and novel nano-sorbent materials. In this review, future prospects for waste to fuels or chemicals and the needed research to further process technologies are discussed. [ABSTRACT FROM AUTHOR]

The formation and dynamics of a single drop of liquid under the influence of gravity can be experienced as everyday phenomena, and have been the subject of scientific investigations since at least the work of Leonardo da Vinci in the early 1500s and Mariotte in the 1680s. Experiences with liquid drops in everyday life are captured by poets and artists as well as scientists, whose theoretical and experimental investigations develop fundamental understanding of drops with size < 1 mm to > 107 m. This paper presents observations of the formation of a single liquid drop of molten steel following bursting of a liquid film formed by illuminating a steel plate by a high energy laser. The hole morphology is analyzed with a proposed kinematic model of hole expansion for the very early stages in the bursting of the hole. Estimates of the hole eccentricity, area, perimeter, and circularity obtained from the model are presented and discussed. Experimental measurements show that a single drop of liquid steel detaches from the end of a neck that then cools to room temperature. Measurements also show that the liquid drop oscillates while falling under gravity. No satellite drops are observed. [ABSTRACT FROM AUTHOR]

Coal has been the main energy source in China for a long period. Therefore, the energy industry must improve coal power generation efficiency and achieve near-zero CO2 emissions. Integrated gasification fuel cell (IGFC) systems that combine coal gasification and high-temperature fuel cells, such as solid oxide fuel cells or molten carbonate fuel cells (MCFCs), are proving to be promising for efficient and clean power generation, compared with traditional coal-fired power plants. In 2017, with the support of National Key R&D Program of China, a consortium led by the China Energy Group and including 12 institutions was formed to develop the advanced IGFC technology with near-zero CO2 emissions. The objectives of this project include understanding the performance of an IGFC power generation system under different operating conditions, designing master system principles for engineering optimization, developing key technologies and intellectual property portfolios, setting up supply chains for key materials and equipment, and operating the first megawatt IGFC demonstration system with near-zero CO2 emission, in early 2022. In this paper, the main developments and projections pertaining to the IGFC project are highlighted. [ABSTRACT FROM AUTHOR]