Special Issue "Design, Modeling, and Optimization of Novel Fuel Cell Systems"

A special issue of Energies (ISSN 1996-1073). This special issue belongs to the section "Hydrogen Energy".

Deadline for manuscript submissions: 30 November 2021.
Submit your paper and select the Journal "Energies" and the Special Issue "Design, Modeling, and Optimization of Novel Fuel Cell Systems" via: https://susy.mdpi.com/user/manuscripts/upload?journal=energies. Please contact the journal editor Adele Min ([email protected]) for any queries.

Special Issue Editor

Dr. Alexandros Arsalis
E-Mail Website
Guest Editor
Research Centre for Sustainable Energy (FOSS), University of Cyprus, Nicosia 1678, Cyprus
Interests: photovoltaic-based systems with hydrogen storage; photovoltaic-electrolyzer-gas turbine distributed energy systems; solid oxide fuel cell-gas turbine-steam turbine cogeneration; fuel cell micro-combined-heat-and-power total energy systems; proton exchange membrane fuel cell-absorption chiller power-and-cooling; steam methane reforming for hydrogen generation; analysis of synergies and development of efficient operational strategies; thermoeconomic modeling; exergy analysis

Special Issue Information

Dear Colleagues,

The interest in novel fuel cell systems is continuously increasing in the world. With the growing global energy demand and the need to reduce carbon emissions, efficient energy conversion is increasing in many areas. Fuel cell systems provide energy solutions in the residential, industrial, and commercial sectors, with stationary, vehicular, and mobile applications. Although fuel cell-based systems are not limited by the type of fuel, they have been considered as a method of converting green electricity from renewable energy sources to hydrogen, which can be stored and used from fuel cells, when electricity generation is unavailable from RES.

This Special Issue will focus on the design, modeling, and optimization of novel fuel cell systems. Papers are invited in all different areas of fuel cell technology, provided they are system-level studies. The submitted work may involve research areas such as thermodynamics, computational fluid dynamics, electrochemistry, and economic and environmental aspects. Both theoretical and experimental work, and, especially, the combination of these, are welcome. Recently, the potential of combining renewable energy sources and fuel cell technology has been raised, and therefore papers addressing such topics are encouraged.

Topics of interest for publication include, but are not limited to, the following:

  • Innovative and alternative approaches to the design and modeling of fuel cell systems
  • Studies of fuel cell-based systems related to economic and/or environmental aspects
  • Photovoltaic or wind turbine-fuel cell hybrid energy systems
  • Flexi-fuel stationary SOFC-based systems
  • Methanol-fueled PEMFC systems for onboard applications
  • Green marine propulsion power plants and hybridization options with conventional propulsion
  • Combination of fuel cell technology with refrigeration cycles
  • Alternative methods of electrolysis applied at the system level
  • System analysis for solar-driven CO2 electrolysis
  • Hydrogen production using solid oxide electrolysis integrated with renewable heat and power
  • Application of novel control strategies in fuel cell systems

Dr. Alexandros Arsalis
Guest Editor

Manuscript Submission Information

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Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • fuel cell systems
  • electrolysis
  • cogeneration
  • hydrogen
  • energy conversion

Published Papers (8 papers)

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Research

Article
A Compact, Self-Sustaining Fuel Cell Auxiliary Power Unit Operated on Diesel Fuel
Energies 2021, 14(18), 5909; https://0-doi-org.brum.beds.ac.uk/10.3390/en14185909 - 17 Sep 2021
Viewed by 485
Abstract
A complete fuel cell-based auxiliary power unit in the 7.5 kWe power class utilizing diesel fuel was developed in accordance with the power density and start-up targets defined by the U.S. Department of Energy. The system includes a highly-integrated fuel processor with [...] Read more.
A complete fuel cell-based auxiliary power unit in the 7.5 kWe power class utilizing diesel fuel was developed in accordance with the power density and start-up targets defined by the U.S. Department of Energy. The system includes a highly-integrated fuel processor with multifunctional reactors to facilitate autothermal reforming, the water-gas shift reaction, and catalytic combustion. It was designed with the help of process analyses, on the basis of which two commercial, high-temperature PEFC stacks and balance of plant components were selected. The complete system was packaged, which resulted in a volume of 187.5 l. After achieving a stable and reproducible stack performance based on a modified break-in procedure, a maximum power of 3.3 kWe was demonstrated in a single stack. Despite the strong deviation from design points resulting from a malfunctioning stack, all system functions could be validated. By scaling-up the performance of the functioning stack to the level of two stacks, a power density of 35 We l−1 could be estimated, which is close to the 40 We l−1 target. Furthermore, the start-up time could be reduced to less than 22 min, which exceeds the 30 min target. These results may bring diesel-based fuel cell auxiliary power units a step closer to use in real applications, which is supported by the demonstrated indicators. Full article
(This article belongs to the Special Issue Design, Modeling, and Optimization of Novel Fuel Cell Systems)
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Article
Optimization Algorithms: Optimal Parameters Computation for Modeling the Polarization Curves of a PEFC Considering the Effect of the Relative Humidity
Energies 2021, 14(18), 5631; https://0-doi-org.brum.beds.ac.uk/10.3390/en14185631 - 07 Sep 2021
Viewed by 631
Abstract
The development of green energy conversion devices has been promising to face climate change and global warming challenges over the last few years. Energy applications require a confident performance prediction, especially in polymer electrolyte fuel cell (PEFC), to guarantee optimal operation. Several researchers [...] Read more.
The development of green energy conversion devices has been promising to face climate change and global warming challenges over the last few years. Energy applications require a confident performance prediction, especially in polymer electrolyte fuel cell (PEFC), to guarantee optimal operation. Several researchers have employed optimization algorithms (OAs) to identify operating parameters to improve the PEFC performance. In the current study, several nature-based OAs have been performed to compute the optimal parameters used to describe the polarization curves in a PEFC. Different relative humidity (RH) values, one of the most influential variables on PEFC performance, have been considered. To develop this study, experimental data have been collected from a lab-scale fuel cell test system establishing different RH percentages, from 18 to 100%. OAs like neural network algorithm (NNA), improved grey-wolf optimizer (I-GWO), ant lion optimizer (ALO), bird swarm algorithm (BSA), and multi-verse optimization (MVO) were evaluated and compared using statistical parameters as training error and time. Results gave enough information to conclude that NNA had better performance and showed better results over other highlighted OAs. Finally, it was found that sparsity and noise are more present at lower relative humidity values. At low RH, a PEFC operates under critical conditions, affecting the fitting on OAs. Full article
(This article belongs to the Special Issue Design, Modeling, and Optimization of Novel Fuel Cell Systems)
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Article
Mass Transport Limitations of Water Evaporation in Polymer Electrolyte Fuel Cell Gas Diffusion Layers
Energies 2021, 14(10), 2967; https://0-doi-org.brum.beds.ac.uk/10.3390/en14102967 - 20 May 2021
Viewed by 576
Abstract
Facilitating the proper handling of water is one of the main challenges to overcome when trying to improve fuel cell performance. Specifically, enhanced removal of liquid water from the porous gas diffusion layers (GDLs) holds a lot of potential, but has proven to [...] Read more.
Facilitating the proper handling of water is one of the main challenges to overcome when trying to improve fuel cell performance. Specifically, enhanced removal of liquid water from the porous gas diffusion layers (GDLs) holds a lot of potential, but has proven to be non-trivial. A main contributor to this removal process is the gaseous transport of water following evaporation inside the GDL or catalyst layer domain. Vapor transport is desired over liquid removal, as the liquid water takes up pore space otherwise available for reactant gas supply to the catalytically active sites and opens up the possibility to remove the waste heat of the cell by evaporative cooling concepts. To better understand evaporative water removal from fuel cells and facilitate the evaporative cooling concept developed at the Paul Scherrer Institute, the effect of gas speed (0.5–10 m/s), temperature (30–60 °C), and evaporation domain (0.8–10 mm) on the evaporation rate of water from a GDL (TGP-H-120, 10 wt% PTFE) has been investigated using an ex situ approach, combined with X-ray tomographic microscopy. An along-the-channel model showed good agreement with the measured values and was used to extrapolate the differential approach to larger domains and to investigate parameter variations that were not covered experimentally. Full article
(This article belongs to the Special Issue Design, Modeling, and Optimization of Novel Fuel Cell Systems)
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Article
Development of a Flexible Framework Multi-Design Optimization Scheme for a Hand Launched Fuel Cell-Powered UAV
Energies 2021, 14(10), 2951; https://0-doi-org.brum.beds.ac.uk/10.3390/en14102951 - 20 May 2021
Viewed by 518
Abstract
This paper presents different methods for the design of a hand-launchable, fixed wing, fuel cell-powered unmanned aerial vehicle (UAV) to maximize flight endurance during steady level flight missions. The proposed design methods include the development of physical models for different propulsion system components. [...] Read more.
This paper presents different methods for the design of a hand-launchable, fixed wing, fuel cell-powered unmanned aerial vehicle (UAV) to maximize flight endurance during steady level flight missions. The proposed design methods include the development of physical models for different propulsion system components. The performance characteristics of the aircraft are modeled through empirical contributing analyses in which each analysis corresponds to an aircraft subsystem. The contributing analyses are collected to form a design structure matrix which is included into a multi-disciplinary analysis to solve for the design variables over a defined design space. The optimal solution is found using a comprehensive optimization tool developed for long endurance flight missions. Optimization results showed a significant improvement in UAV flight endurance that reached up to 475 min with take-off ratio equals to 59 min/kg. Wind tunnel and bench-top tests and HiL simulation tests are performed to validate the results obtained from the optimization tools. Validated optimization results showed an increase of the overall UAV flight endurance by 19.4% compared to classical approaches in design methods. Full article
(This article belongs to the Special Issue Design, Modeling, and Optimization of Novel Fuel Cell Systems)
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Article
Cooling Design for PEM Fuel-Cell Stacks Employing Air and Metal Foam: Simulation and Experiment
Energies 2021, 14(9), 2687; https://0-doi-org.brum.beds.ac.uk/10.3390/en14092687 - 07 May 2021
Viewed by 460
Abstract
A new study investigating the cooling efficacy of air flow inside open-cell metal foam embedded in aluminum models of fuel-cell stacks is described. A model based on a commercial stack was simulated and tested experimentally. This stack has three proton exchange membrane (PEM) [...] Read more.
A new study investigating the cooling efficacy of air flow inside open-cell metal foam embedded in aluminum models of fuel-cell stacks is described. A model based on a commercial stack was simulated and tested experimentally. This stack has three proton exchange membrane (PEM) fuel cells, each having an active area of 100 cm2, with a total output power of 500 W. The state-of-the-art cooling of this stack employs water in serpentine flow channels. The new design of the current investigation replaces these channels with metal foam and replaces the actual fuel cells with aluminum plates. The constant heat flux on these plates is equivalent to the maximum heat dissipation of the stack. Forced air is employed as the coolant. The aluminum foam used had an open-pore size of 0.65 mm and an after-compression porosity of 60%. Local temperatures in the stack and pumping power were calculated for various air-flow velocities in the range of 0.2–1.5 m/s by numerical simulation and were determined by experiments. This range of air speed corresponds to the Reynolds number based on the hydraulic diameter in the range of 87.6–700.4. Internal and external cells of the stack were investigated. In the simulations, and the thermal energy equations were solved invoking the local thermal non-equilibrium model—a more realistic treatment for airflow in a metal foam. Good agreement between the simulation and experiment was obtained for the local temperatures. As for the pumping power predicted by simulation and obtained experimentally, there was an average difference of about 18.3%. This difference has been attributed to the poor correlation used by the CFD package (ANSYS) for pressure drop in a metal foam. This study points to the viability of employing metal foam for cooling of fuel-cell systems. Full article
(This article belongs to the Special Issue Design, Modeling, and Optimization of Novel Fuel Cell Systems)
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Article
Enhancing the Specific Power of a PEM Fuel Cell Powered UAV with a Novel Bean-Shaped Flow Field
Energies 2021, 14(9), 2494; https://0-doi-org.brum.beds.ac.uk/10.3390/en14092494 - 27 Apr 2021
Cited by 2 | Viewed by 528
Abstract
One of the marketing challenges of unmanned aerial vehicles (UAVs) for various applications is enhancing flight durability. Due to the superior characteristics of proton exchange membrane fuel cells (PEMFCs), they have the potential to reach a longer flight time and higher payload. In [...] Read more.
One of the marketing challenges of unmanned aerial vehicles (UAVs) for various applications is enhancing flight durability. Due to the superior characteristics of proton exchange membrane fuel cells (PEMFCs), they have the potential to reach a longer flight time and higher payload. In this regard, a numerical assessment of a UAV air-cooled PEMFC is carried out using a three-dimensional (3-D), multiphase, and non-isothermal model on three flow fields, i.e., unblocked bean-shaped, blocked bean-shaped, and parallel. Then, the results of single-cell modeling are generalized to the PEMFC stack to provide the power of 2.5 kW for a UAV. The obtained results indicate that the strategy of rising air stoichiometry for cooling performs well in the unblocked bean-shaped design, and the maximum temperature along the channel length reaches 331.5 K at the air stoichiometric of 30. Further, it is found that the best performance of a 2.5 kW PEMFC stack is attained by the bean-shaped design without blockage, of which its volume and mass power density are 1.1 kW L−1 and 0.2 kW kg−1, respectively. It is 9.4% lighter and 6.9% more compact than the parallel flow field. Therefore, the unblocked bean-shaped design can be a good option for aerial applications. Full article
(This article belongs to the Special Issue Design, Modeling, and Optimization of Novel Fuel Cell Systems)
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Article
Resistance Separation of Polymer Electrolyte Membrane Fuel Cell by Polarization Curve and Electrochemical Impedance Spectroscopy
Energies 2021, 14(5), 1491; https://0-doi-org.brum.beds.ac.uk/10.3390/en14051491 - 09 Mar 2021
Cited by 3 | Viewed by 621
Abstract
The separation of resistances during their measurement is important because it helps to identify contributors in polymer electrolyte membrane (PEM) fuel cell performance. The major methodologies for separating the resistances are electrochemical impedance spectroscopy (EIS) and polarization curves. In addition, an equivalent circuit [...] Read more.
The separation of resistances during their measurement is important because it helps to identify contributors in polymer electrolyte membrane (PEM) fuel cell performance. The major methodologies for separating the resistances are electrochemical impedance spectroscopy (EIS) and polarization curves. In addition, an equivalent circuit was selected for EIS analysis. Although the equivalent circuit of PEM fuel cells has been extensively studied, less attention has been paid to the separation of resistances, including protonic resistance in the cathode catalyst layer (CCL). In this study, polarization curve and EIS analyses were conducted to separate resistances considering the charge transfer resistance, mass transport resistance, high frequency resistance, and protonic resistance in the CCL. A general solution was mathematically derived using the recursion formula. Consequently, resistances were separated and analyzed with respect to variations in relative humidity in the entire current density region. In the case of ohmic resistance, high frequency resistance was almost constant in the main operating load range (0.038–0.050 Ω cm2), while protonic resistance in the CCL exhibited sensitivity (0.025–0.082 Ω cm2) owing to oxygen diffusion and water content. Full article
(This article belongs to the Special Issue Design, Modeling, and Optimization of Novel Fuel Cell Systems)
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Article
Study of Long-Term Stability of Ni-Zr0.92Y0.08O2-δ|Zr0.92Y0.08O2-δ|Ce0.9Gd0.1O2-δ |Pr0.6Sr0.4CoO3-δ at SOFC and SOEC Mode
Energies 2021, 14(4), 824; https://0-doi-org.brum.beds.ac.uk/10.3390/en14040824 - 04 Feb 2021
Cited by 2 | Viewed by 643
Abstract
Long term stability is one of the decisive properties of solid oxide fuel cell (SOFC) as well as solid oxide electrolysis cell (SOEC) materials from the commercialization perspective. To improve the understanding about degradation mechanisms solid oxide cells with different electrode compositions should [...] Read more.
Long term stability is one of the decisive properties of solid oxide fuel cell (SOFC) as well as solid oxide electrolysis cell (SOEC) materials from the commercialization perspective. To improve the understanding about degradation mechanisms solid oxide cells with different electrode compositions should be studied. In this work, Ni-Zr0.92Y0.08O2-δ (Ni-YSZ)| Zr0.92Y0.08O2-δ (YSZ)|Ce0.9Gd0.1O2-δ (GDC)|Pr0.6Sr0.4CoO3-δ (PSC) cells are tested in the SOFC regime for 17,820 h at 650 °C, and in the SOEC regime for 860 h at 800 °C. The SOFC experiment showed a degradation speed of 2.4% per 1000 h at first but decreased to 1.1% per 1000 h later. The electrolysis test was performed for 860 h at 800 °C. The degradation speed was 16.3% per 1000 h. In the end of the stability tests, an electrode activity mapping was carried out using a novel 18O tracing approach. Average Ni grain sizes were measured and correlated with the results of the oxygen isotope maps. Results indicate that Ni coarsening is dependent on solid oxide cell activity. Strontium, chromium and silicon concentrations were also analyzed using the ToF-SIMS method and compared to the electrode activity map, but significant correlation was not observed. Full article
(This article belongs to the Special Issue Design, Modeling, and Optimization of Novel Fuel Cell Systems)
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