Numerical modeling and simulations of active direct methanol fuel cell (DMFC) systems under various ambient temperatures and operating conditions

Lee, Jun-Hee; Lee, Suwon; Han, Dong; Gwak, Geonhui; Ju, Hyunchul

doi:10.1016/j.ijhydene.2016.09.087

Cited by 50 publications

(16 citation statements)

References 23 publications

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“…oxygen and water concentration, pressure, temperature), that are leading to locally varying performance limitations; on this, modelling simulations can give fundamental indications. However, modelling analyses dealing with local performance investigation found in the literature [30][31][32] generally lack of rigorous and experimental validation, reducing the reliability of model results or limiting model prediction capabilities.…”

Section: Introductionmentioning

confidence: 99%

A locally resolved investigation on direct methanol fuel cell uneven components fading: Local cathode catalyst layer tuning for homogeneous operation and reduced degradation rate

Rabissi

Zago

Gazdzicki

et al. 2018

Journal of Power Sources

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Durability issues of direct methanol fuel cell still hinder technology widespread commercialization; uneven aging of MEA components, generally harsher in air outlet region, is known to exasperate overall performance degradation. In a previous work, the authors selected a stable cathode electrode, demonstrated to fade homogenously: uneven water-related limitations, such as dehydration and flooding, were revealed to locally worsen performance at cathode inlet and outlet regions, leading to current redistribution. Aiming to reduce degradation rate, in this work homogeneous current distribution during operation is pursued by tuning MEA properties to meet local operating conditions. A properly improved 1D+1D physical model is used to support the development of a gradient MEA, featuring 1.6 mg•cm-2 and 0.8 mg•cm-2 of catalyst and ionomer respectively at inlet/outlet and center regions of cathode electrode. Tests based on custom macro-segmented cell demonstrated 55% more homogeneous current distribution, controllable during operation by means of cathode air This work is licensed under the Creative Commons Attribution 3.

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Section: Introductionmentioning

confidence: 99%

A locally resolved investigation on direct methanol fuel cell uneven components fading: Local cathode catalyst layer tuning for homogeneous operation and reduced degradation rate

Rabissi

Zago

Gazdzicki

et al. 2018

Journal of Power Sources

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“…The mass transfer in the gas diffusion layer is governed by the Maxwell-Stefan laws, and accounts for the porosity and tortuosity through a factor implemented through a Bruggeman correction 38 for the mass transfer in a porous medium, as given by equation (9), where D eff ik , ε, and D ik are the corrected diffusion coefficient, porosity, and free flow diffusion coefficient, respectively. The mass transfer in the gas diffusion layer is governed by the Maxwell-Stefan laws, and accounts for the porosity and tortuosity through a factor implemented through a Bruggeman correction 38 for the mass transfer in a porous medium, as given by equation (9), where D eff ik , ε, and D ik are the corrected diffusion coefficient, porosity, and free flow diffusion coefficient, respectively.…”

Section: Governing Equationsmentioning

confidence: 99%

“…The charge conservation is also applied in the gas diffusion layer through Ohm's law. The mass transfer in the gas diffusion layer is governed by the Maxwell-Stefan laws, and accounts for the porosity and tortuosity through a factor implemented through a Bruggeman correction 38 for the mass transfer in a porous medium, as given by equation (9), where D eff ik , ε, and D ik are the corrected diffusion coefficient, porosity, and free flow diffusion coefficient, respectively.…”

Section: Governing Equationsmentioning

confidence: 99%

Performance enhancement of direct methanol fuel cell using multi‐zone narrow flow fields

2019

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Summary New serpentine and spiral flow field configurations were developed to enhance the performance of direct methanol fuel cells (DMFCs). The new configurations are based on two primary concepts, namely, narrowing the flow field and partitioning the total active area of the fuel cell. Three flow channel heights of 0.8, 0.4, and 0.2 mm were investigated in serpentine and spiral flow fields. The main active area is considered a single zone and is partitioned into two‐ and four‐zone designs while maintaining the total inlet mass flow rate of the reactant and oxidant. To determine the performance parameters of the newly proposed designs, a three‐dimensional single‐phase isothermal model was developed, numerically simulated, and validated through experimental measurements. The findings of the current study indicate that a serpentine flow field configuration with a channel height of 0.2 mm and two zones attains an enhancement of the net power density of 37% compared to a conventional single‐zone design with a flow channel height of 0.8 mm. Similarly, for a spiral flow field design, the maximum net power density increased by 26% using a two‐zone configuration with a channel height of 0.2 mm, in comparison to the conventional design of a single‐zone and a flow channel height of 0.8 mm. The newly developed designs utilize the lower height of the flow fields to decrease the dimensions of the fuel cell stacks and reduce the material costs required.

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“…However, they also observed that the energetic efficiency was dependent strongly on the DMFC stack temperature, higher temperatures causing lower fuel efficiencies. 25 In this study, energetic, faradaic, and fuel efficiencies of DMFC under mid-term operation conditions were investigated by considering methanol crossover as well as the generation of intermediate products such as formaldehyde and formic acid.…”

Section: Introductionmentioning

confidence: 99%

Experimental evaluation of the efficiency performance of the DMFC

Ciğeroğlu

Kazan

2020

Env Prog and Sustain Energy

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This study represents the experimental assessment of the faradaic, fuel, and energetic efficiency of active direct methanol fuel cell (DMFC). The experimental system was equipped with several sensors, HPLC and UV spectroscopy to make on-line and off-line measurements of different components. A polarization study was conducted and an experimental plan was applied to collect the process data during 3-hour runs. Finally, stoichiometric and various efficiency calculations were performed based on the system and the process data. The results showed that the cell performance was better at higher operating temperatures (70.8 mW cm −2 @75 C). Faradaic efficiency and fuel efficiency were better at low temperatures and estimated as 55.8% and 59.6% at 55 C, respectively. Energetic efficiency was better at higher temperatures due to the faster anode kinetics and was found as 12.3% at 75 C. The efficiencies were strongly dependent on methanol concentration. Methanol crossover was increased with increasing methanol concentration; hence the efficiencies were decreased.

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Numerical modeling and simulations of active direct methanol fuel cell (DMFC) systems under various ambient temperatures and operating conditions

Cited by 50 publications

References 23 publications

A locally resolved investigation on direct methanol fuel cell uneven components fading: Local cathode catalyst layer tuning for homogeneous operation and reduced degradation rate

A locally resolved investigation on direct methanol fuel cell uneven components fading: Local cathode catalyst layer tuning for homogeneous operation and reduced degradation rate

Performance enhancement of direct methanol fuel cell using multi‐zone narrow flow fields

Experimental evaluation of the efficiency performance of the DMFC

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