A new hybrid system consisting of a PEMFC (proton exchange membrane fuel cell) subsystem and a TREC (thermally regenerative electrochemical cycle) subsystem is proposed to convert the waste heat ...produced by the PEMFC system into electricity. The performance of the hybrid system and its corresponding subsystems is analyzed. Results reveal that there exists optimal current densities of the PEMFC and TREC systems leading to the maximum power output of the hybrid system. With the maximum power output as the objective function, an optimization of the hybrid system based on genetic algorithm method is conducted under different operating temperatures of the PEMFC subsystem. The power output of the hybrid system is 6.85%–20.59% larger than that of the PEMFC subsystem. And the total electrical efficiency is improved by 2.74%–8.27%. The corresponding electrical efficiency of the TREC is 4.56%–13.81%. The hybrid system proposed in this paper could contribute to utilizing the fuel energy more efficiently and sufficiently.
•A hybrid power system consisting of a PEMFC and a TREC subsystems is proposed.•Parameters' impacts on performance of the hybrid system have been analyzed.•The maximum power output of the hybrid system is investigated based on genetic algorithm.•Total power output of the hybrid system is 7.63%–18.84% larger than that of the PEMFC subsystem.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The utilization of modeling techniques for Proton Exchange Membrane Fuel Cells (PEMFC) presents a viable and proficient approach for comprehending, enhancing, and increasing the efficiency of these ...sustainable energy sources. This is of paramount importance in tackling worldwide anxieties regarding ecological contamination and the lessening of non-renewable resources of energy. The authors of this research paper introduce a novel approach for the efficient detection of output voltage in PEMFC. This approach involves the utilization of an optimized Ridgelet Neural Network (RNN) in conjunction with a Hybrid Northern Goshawk Optimization (HNGO) algorithm. The primary aim of the proposed approach is to reduce the discrepancy among the determined and anticipated resulted voltages of the PEMFC. This is a vital aspect in increasing the fuel cells' efficacy. The authors conducted simulations to assess the efficacy of the proposed approach. The outcomes designated that the RNN/HNGO method outperforms existing methods when it comes to accuracy in tracking voltage signal predictions. Moreover, the proposed approach yields a comparatively lower level of forecast error compared to previously published studies. The aforementioned results underscored the possibility of utilizing the suggested approach in enhancing the performance of PEMFC through practical means. Additionally, the authors propose that the methodology they have presented has the potential to be expanded to encompass other performance metrics of PEMFCs, including power and efficiency. The authors propose the integration of the RNN/HNGO method with additional optimization techniques or its utilization in hybrid systems as a means of augmenting its performance. The authors concluded by acknowledging the need for additional research to experimentally validate the proposed methodology and optimizing its parameters in order to ensure its reliability and applicability in real-world scenarios.
•Optimal identification of PEMFC output voltage using an optimized RNN.•Optimizing RNN using a Hybrid Version of Northern Goshawk Optimization Algorithm.•Minimization of error between observed and predicted output voltages in PEMFCs.•Improved accuracy in tracking voltage signal predictions compared to existing methods.•Comparison with other published works to validate its effectiveness.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•A dynamic compressor model is developed that can predicts compressor surge.•An MRAC algorithm is designed to prevent compressor surge with more acceptable convergence.•System simulation is carried ...out to confirm feasibility of MRAC under dynamic environment.•By algorithm comparison, MRAC is proven to be more feasible for surge rejection.•MRAC comes to be more reliable under nominal dynamic operating schedules.
Surge control in a centrifugal air compressor is crucial to ensure the reliable operation of a fuel cell system, but few studies have reported on compressor surges in fuel cell systems. This study presents an effective surge control algorithm with a surge predictive compressor model under various operating conditions of an automotive fuel cell system. Unlike previous studies on the air management systems of an automotive fuel cell, this study presents an analytic compressor model which is a nonlinear dynamic model with surge prediction capability. In this study, a model reference adaptive control (MRAC) is introduced, to avoid compressor surge during the dynamic operation of a fuel cell system. The adaptive control was compared with the nominal feedback control in the air management system of an automotive fuel cell operating within normal conditions, under transient and steady-state responses. Also, when a surge was detected in the system, the adaptive control algorithm was fast enough to recover the air mass flow rate to normal ranges. Based on these results, it can be concluded that the MRAC algorithm shows better performance than the nominal feedback control algorithm with respect to the transient behaviors and surge recovery of an automotive fuel cell system.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Temperature control is a critical issue to ensuring the reliable performance of fuel cell systems. However, nominal feedback controllers currently used to regulate system temperature have ...limitations, due to the high inherent nonlinearity in the systems, and uncertainty in the parameters of the models, especially in the presence of dynamic load variations. In this study, a feedback controller was designed including Model Reference Adaptive Control (MRAC) to address uncertainties and robustly control the stack and the coolant inlet temperature in a proton exchange membrane fuel cell (PEMFC). The proposed controller was then evaluated by comparison with a nominal feedback controller. It was shown that if the parameters vary in the system the MRAC algorithm yields improved transient performances in terms of recovery speed and deviation in comparison to the nominal feedback control algorithm. The MRAC provides enhanced robustness.
•A thermal management module is designed to predict the cooling performance.•An MRAC algorithm is designed to control the fuel system temperature.•Simulation is carried out to confirm feasibility of MRAC under dynamic load.•By algorithm comparison, MRAC is proven to be more feasible for controlling the system temperature.•MRAC comes to be more reliable under nominal dynamic operating schedules.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The commercial viability of PEMFC (proton exchange membrane fuel cell) systems depends on using effective fault diagnosis technologies in PEMFC systems. However, many researchers have experimentally ...studied PEMFC (proton exchange membrane fuel cell) systems without considering certain fault conditions. In this paper, an ANN (artificial neural network) ensemble method is presented that improves the stability and reliability of the PEMFC systems. In the first part, a transient model giving it flexibility in application to some exceptional conditions is built. The PEMFC dynamic model is built and simulated using MATLAB. In the second, using this model and experiments, the mechanisms of four different faults in PEMFC systems are analyzed in detail. Third, the ANN ensemble for the fault diagnosis is built and modeled. This model is trained and tested by the data. The test result shows that, compared with the previous method for fault diagnosis of PEMFC systems, the proposed fault diagnosis method has higher diagnostic rate and generalization ability. Moreover, the partial structure of this method can be altered easily, along with the change of the PEMFC systems. In general, this method for diagnosis of PEMFC has value for certain applications.
•We analyze the principles and mechanisms of the four faults in PEMFC (proton exchange membrane fuel cell) system.•We design and model an ANN (artificial neural network) ensemble method for the fault diagnosis of PEMFC system.•This method has high diagnostic rate and strong generalization ability.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
In this paper, a numerical study is conducted in order to investigate the effect of pulsation of air flow at the cathode side of Proton Exchange Membrane (PEM) fuel cell with interdigitated flow ...field. A two dimensional, isothermal, two-phase, unsteady multi-component transport model is used in order to simulate the transport phenomena. The obtained results are discussed in terms of the influence of flow pulsation on water management and cell performance. The results prove the effectiveness of flow pulsation on improving water removal from cell, enhancing reactants transports to the reaction sites, and increasing the cell performance expressed by increment in the cell limiting current density and maximum output power. The effects of pulsation frequency (f), amplitude (Amp), and mean inlet pressure (Pin) on the performance and the output power of the cell, are also investigated. The performance of the cell has no dependency on the frequency range considered in this study. However, as the pulsation amplitude increases the increment in the cell performance is more obvious. Moreover, applying flow pulsation at low flow rates leads to higher efficiency in water removal and performance enhancement.
•Mechanism of water and oxygen transport under flow pulsation are discussed.•Pulsating cathode flow increases the limiting current density and output power.•The performance of cell has no significant dependency on pulsation frequency.•The performance and output power increase with the pulsation amplitude.•Using pulsating flow at lower average pressures leads to higher water removal rate.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
► Coated aluminium bipolar plates demonstrate the hydrophobic property than the raw material. ► The corrosion behaviour of bipolar plate decreases the PEMFC performance severely. ► These PEMFCs are ...measured by current–voltage (I–V) curve test. ► The oxide film increases the interfacial contact resistance.
The performance of Al-alloy bipolar plates for the PEMFC (proton exchange membrane fuel cell) system is investigated in this paper. The metallic bipolar plates are modified with a Ni–P coating. The performance of the Al-alloy bipolar plates is evaluated by the coating structure, corrosion resistance, contact angle and single cell performance. The results indicate that the coated aluminium bipolar plates demonstrate hydrophobic and anti-corrosive properties. The hydrophobic property increases the contact angle on the surface from 46.08° to 80.51°. Meanwhile, the corrosion rate of the Ni–P coating can be over 1 order of magnitude lower than that of the substrate. Hence, the substrate with the coating maintains superior performance under the long term test. The present study proves that both the hydrophobicity and corrosion resistance significantly affect the metallic bipolar plate.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
A successful approach towards enhancement in ion cluster size of sulfonated poly (arylene ether sulfone) (SPAES)-based membranes has been successfully carried out by encapsulating basic pendent ...branches as side groups. Modified SPAES was synthesized by condensation polymerization followed by bromination with N-bromosuccinamide (NBS) and sulfonation by ring opening reaction. Various molar ratios of branched polyethyleneimine (PEI) were added to the SPAES and the developed polymer was designated as SPAES-x-PEI-y, where
denoted the number of sulfonating acid group per polymer chain and y represents the amount of PEI concentration. Polymer synthesis was characterized by
H-NMR (Nuclear magnetic resonance) and FT-IR (Fourier-transform infrared spectroscopy) analysis. A cumulative trend involving enhanced proton conductivity of the membranes with an increase in the molar ratio of PEI has been observed, clearly demonstrating the formation of ionic clusters. SPAES-140-PEI-3 membranes show improved proton conductivity of 0.12 Scm
at 80 °C. Excellent chemical stability was demonstrated by the polymer with Fenton's test at 80 °C for 24 h without significant loss in proton conductivity, owing to the suitability of the synthesized hybrid membrane for electrochemical application. Moreover, a single cell degradation test was conducted at 80 °C showing a power density at a 140 mWcm
value, proving the stable nature of synthesized membranes for proton exchange membrane fuel cell application.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
High purity hydrogen produced by hydrolysis of sodium borohydride can be used directly in (proton exchange membrane) PEM fuel cells for portable devices and automotive applications. The advantages of ...high storage capacity, quickly start, controllable reaction and mild condition, hydrogen generation by catalytic hydrolysis of chemical hydride, such as sodium borohydride, has attracted much attention for development recently.
Development and optimal design of a hydrogen generator based on (sodium borohydride) NaBH4 using Ru catalyst are reported in the present study. A multi-layer coating process of Ru on Ni foam was employed to enhance its capability for hydrogen generation cycles. The optimal deposition density of Ru particles on Ni foam was confirmed by the SEM (scanning electron microscopy) morphology. The cycling generation for the steady state reaction can be maintained at least 10 times. The activity of Ru catalyst during a hydrogen generation process was examined in a continuous flow reactor. In general, NaBH4 solution cannot be fully utilized through the hydrogen generator, as a result, the effluent from the generator may continue to dissociate, which turns into hydrogen leakage. A secondary reactor was therefore installed after the primary generator to collect the remaining hydrogen. The reactant solution containing 20 wt.% NaBH4 and 3 wt.% NaOH was introduced into the structured catalyst at a constant flow rate using a liquid pump, and H2 rate of 1.72 L min−1 (0.43 L (H2) min−1 g−1 catalyst). The conversion of NaBH4 from flow rates of hydrogen was about 92.2%.
The present hydrogen generator was later integrated with a 100 W PEM fuel cell and the performance of the integrated system was investigated. The hydrogen produced from NaBH4 has high purity and saturated humidity; therefore, it can be directly used as the fuel for PEMFCs (proton exchange membrane fuel cells), which in general require humidified hydrogen. It is found that for cell voltage above 0.6 V, the performance of cell using NaBH4 hydrogen is 103.45 W, versus 99.9 W with cylinder hydrogen. The cell performance using the hydrogen from NaBH4 is 3.6% higher than that using cylinder hydrogen.
► Development and optimal design of a hydrogen generator based on (sodium borohydride) NaBH4 using Ru catalyst. ► A multi-layer coating process of Ru on Ni foam was employed to enhance its capability for hydrogen generation cycles. ► The activity of Ru catalyst during hydrogen generation process was examined in a continuous flow reactor. ► The hydrogen generator was integrated with a 100 W PEM fuel cell.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
During the assembly of a fuel cell, the mechanical stress and strain that occur have a significantly large effect on the performance and reliability of fuel cell. When assembling a fuel cell stack, ...the assembly pressure generated can decrease the interfacial contact resistance (ICR) between the bipolar plate (BPP), gas diffusion layer (GDL) and catalyst layer, and also, the reduction in mass transfer that happens during the electrochemical reaction in the catalyst layer through the GDL must be considered. Recent research on the numerical analysis of fuel cells does not take into account the aforementioned importance of the GDL compression deformation, claiming the restrictions of numerical analysis, and uses a simple model to analyze the mass transfer of the fuel cells using CFD analysis. Therefore in this research, the performance of the fuel cell (e.g. pressure drop, gas permeability of GDL, and the electrolyte membrane water content (λ) were compared for the FSI model, which is a thermal·fluid based PEMFC model (CFD model) that takes the GDL compression deformation into account. The GDL compression deformation, dependent on the fuel cell assembly pressure, affects the gas permeability caused by under-rib convection. As a result in the inlet of the fuel cell, the internal pressure and flow velocity increase due to the decrease in cross sectional area, but due to the decreased gas permeability of the rib it has a low current density, and as the outlet is approached, it can be determined that the current density actually increases due to the hydrogen and oxygen mass fractions being greater than the CFD model making the current density more uniform overall. Therefore using the FSI analysis method, it is important to predict the optimized fuel cell architecture and operating condition parameters.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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