3D Numerical Study of a Flowing Electrolyte – Direct Methanol Fuel Cell With an Implemented Bi-Layered Membrane Electrode Diaphragm Assembly

2011 ◽  
Author(s):  
P. A. Cornellier ◽  
E. Matida ◽  
C. A. Cruickshank
Keyword(s):  
Fuel Cell ◽  
Flow Rate ◽  
Direct Methanol Fuel Cell ◽  
Numerical Study ◽  
Experimental Studies ◽  
Membrane Electrode ◽  
Pressure Losses ◽  
Direct Methanol ◽  
Flow Through ◽  
Methanol Fuel Cell

In the present work, fluid dynamic simulation and experimental studies are compared to assess the validity of using computational fluid dynamics (CFD) to accurately predict the pressure losses experienced across each of the three fluid channels in a flowing electrolyte direct methanol fuel cell: methanol flow through anodic-serpentine channels; air flow through the cathodic-serpentine channels; dilute sulfuric acid flow through the flowing electrolyte (FE) channel located between two membrane-electrode assemblies (MEAs). The methanol flow rate is varied from 5 to 25 mL/min and the airflow is varied from 0.5 to 5 L/min. The flowing electrolyte flow rate is also varied from 5 to 25 mL/min in order to analyze pressure levels within the FE channel, which, according to this analysis, must be larger than the adjacent serpentine channels. This pressure difference is particularly important to maintain the distance (and flow structure) between the MEAs without affecting performance of the fuel cell. Adequately controlling the pressure of each of three fluids disables the MEAs ability to deform without the use of an electrolyte spacer, effectively creating an inter-dependent bi-layered membrane electrode diaphragm assembly (Bi-MEDA). Through CFD simulation, it was observed that pressure equalization through the Bi-MEDA approach supports the elimination of a flowing electrolyte channel spacer from current FE-DMFC designs. The reduction of the spacer is expected to decrease ohmic losses currently experienced in all FE-DMFC designs. Despite several approximations, simulations predicting pressure losses throughout the two serpentine fuel channels are compared against obtained experimental data, showing relatively good agreement for a single cell arrangement.

scholarly journals Performance of passive Direct Methanol Fuel Cell: modelling and experimental studies

2017 ◽  
Vol 1 (1) ◽  
pp. 89-103 ◽  
Author(s):  
Beatriz A. Berns ◽  
Mariana F. Torres ◽  
Vânia B. Oliveira ◽  
Alexandra M. F. R. Pinto
Keyword(s):  
Fuel Cell ◽  
Direct Methanol Fuel Cell ◽  
Experimental Studies ◽  
Gas Diffusion ◽  
Membrane Electrode ◽  
Membrane Area ◽  
Diffusion Layers ◽  
Electrode Assemblies ◽  
Direct Methanol ◽  
Methanol Fuel Cell

Low methanol and water crossover with high methanol concentrations are essential requirements for a passive Direct Methanol Fuel Cell (DMFC) to be used in portable applications. Therefore, it is extremely important to clearly understand and study the effect of the different operating and configuration parameters on the cell’s performance and both methanol and water crossover. In the present work, a detailed experimental study on the performance of an in-house developed passive DMFC with 25 cm2 of active membrane area is described. Tailored membrane electrode assemblies (MEAs) with different structures and combinations of gas diffusion layers (GDL) and membranes, were tested in order to select optimal working conditions at high methanol concentration levels without sacrificing performance. The experimental polarization curves were successfully compared with the predictions of a steady state, one-dimensional model accounting for coupled heat and mass transfer, along with the electrochemical reactions occurring in the passive DMFC developed by the same authors.

Prediction of Direct Methanol Fuel Cell Stack Performance Using Artificial Neural Network

2017 ◽  
Vol 14 (3) ◽  
Author(s):  
M. A. Rafe Biswas ◽  
Melvin D. Robinson
Keyword(s):  
Fuel Cell ◽  
Direct Methanol Fuel Cell ◽  
Experimental Studies ◽  
Cell Voltage ◽  
Operating Conditions ◽  
Coefficient Of Determination ◽  
Membrane Electrode ◽  
Direct Methanol ◽  
Artificial Neural ◽  
Methanol Fuel Cell

A direct methanol fuel cell (DMFC) converts liquid fuel into electricity to power devices, while operating at relatively low temperatures and producing virtually no greenhouse gases. Since DMFC performance characteristics are inherently complex, it can be postulated that artificial neural networks (NN) represent a marked improvement in prediction capabilities. In this work, an artificial NN is employed to predict the performance of a DMFC under various operating conditions. Input variables for the analysis consist of methanol concentration, temperature, current density, number of cells, and anode flow rate. The addition of the two latter variables allows for a more distinctive model when compared to prior NN models. The key performance indicator of our NN model is cell voltage, which is an average voltage across the stack and ranges from 0 to 0.8 V. Experimental studies were conducted using DMFC stacks with membrane electrode assemblies consisting of an additional unique liquid barrier layer to minimize water loss to atmosphere. To determine the best fit to the experimental data, the model is trained using two second-order training algorithms: OWO-Newton and Levenberg–Marquardt (LM). The topology of OWO-Newton algorithm is slightly different from that of LM algorithm by employing bypass weights. The application of NN shows rapid construction of a predictive model of cell voltage for varying operating conditions with an accuracy on the order of 10−4, which can be comparable to literature. The coefficient of determination of the optimal model results using either algorithm were greater than 0.998.

Critique and Improvement of a One-Dimensional Semianalytical Model of a Direct Methanol Fuel Cell

2012 ◽  
Vol 9 (5) ◽  
Author(s):  
C. C. Kuo ◽  
W. E. Lear ◽  
J. H. Fletcher ◽  
O. D. Crisalle
Keyword(s):  
Fuel Cell ◽  
Polarization Curve ◽  
Current Density ◽  
Direct Methanol Fuel Cell ◽  
Membrane Electrode Assembly ◽  
Membrane Electrode ◽  
One Dimensional ◽  
Implicit Equation ◽  
Direct Methanol ◽  
Methanol Fuel Cell

A constructive critique and a suite of proposed improvements for a recent one-dimensional semianalytical model of a direct methanol fuel cell are presented for the purpose of improving the predictive ability of the modeling approach. The model produces a polarization curve for a fuel cell system comprised of a single membrane-electrode assembly, based on a semianalytical one-dimensional solution of the steady-state methanol concentration profile across relevant layers of the membrane electrode assembly. The first improvement proposed is a more precise numerical solution method for an implicit equation that describes the overall current density, leading to better convergence properties. A second improvement is a new technique for identifying the maximum achievable current density, an important piece of information necessary to avoid divergence of the implicit-equation solver. Third, a modeling improvement is introduced through the adoption of a linear ion-conductivity model that enhances the ability to better match experimental polarization-curve data at high current densities. Fourth, a systematic method is advanced for extracting anodic and cathodic transfer-coefficient parameters from experimental data via a least-squares regression procedure, eliminating a potentially significant parameter estimation error. Finally, this study determines that the methanol concentration boundary condition imposed on the membrane side of the membrane-cathode interface plays a critical role in the model’s ability to predict the limiting current density. Furthermore, the study argues for the need to carry out additional experimental work to identify more meaningful boundary concentration values realized by the cell.

In-Situ Estimation of Faradaic Efficiency for a Direct Methanol Fuel Cell Stack by a Carbon Dioxide Saturated Solution Method

2009 ◽  
Author(s):  
Liang Qi ◽  
Xiaofeng Xie ◽  
Ibrahim Alaefour ◽  
Aaron Pereira ◽  
Xianguo Li
Keyword(s):  
Fuel Cell ◽  
Flow Rate ◽  
Direct Methanol Fuel Cell ◽  
Solution Method ◽  
Air Flow ◽  
Saturated Solution ◽  
Air Flow Rate ◽  
Faradaic Efficiency ◽  
Direct Methanol ◽  
Methanol Fuel Cell

A direct methanol fuel cell (DMFC) system consisting of 40 single cells was assembled to study the influence of the transport phenomena at the anode and stack faradaic efficiencies by a CO2 saturated solution method. This method corrected the common experimental error in measuring methanol crossover caused by the simultaneous CO2 permeation from the anode to cathode. Both anode and stack faradaic efficiencies were estimated using this method. An equivalent “carbon-flow current” has been defined and a relationship between the transport phenomena and efficiencies was developed. Also the effect of methanol concentration, methanol flow rate and air flow rate on stack efficiency was studied. The results show that lower methanol flow rate, lower methanol concentration and higher air flow rate are all helpful in decreasing the methanol crossover and increase the stack faradaic efficiency.

scholarly journals Experimental Studies on a New Controller Design and Implementation in Direct Methanol Fuel Cell

Processes ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 796
Author(s):  
Ramasamy Govindarasu ◽  
Solaiappan Somasundaram
Keyword(s):  
Fuel Cell ◽  
Real Time ◽  
Direct Methanol Fuel Cell ◽  
Controller Design ◽  
Experimental Studies ◽  
Set Point ◽  
Point Tracking ◽  
Time Operation ◽  
Direct Methanol ◽  
Methanol Fuel Cell

A dynamic model of a Direct Methanol Fuel Cell is developed in the MATLAB platform. A newly proposed Coefficient Diagram based Proportional Integral Controller (CD-PIC) is designed and its parameters are calculated. The newly designed CD-PIC is implemented in a real time Direct Methanol Fuel Cell (DMFC) experimental setup. Performances in real time operation of the Direct Methanol Fuel Cell (DMFC) are evaluated. The performance of CD-PIC is obtained under tracking of set point changes. In order to evaluate the CD-PIC performances, most popular tuning rules based Conventional PI Controllers (C-PIC) are also designed and analyzed. Set point tracking is carried out for the step changes of ±10% and ±15% at two different operational points. The controller performances are analyzed in terms of Controller Performance Measuring (CPM) indices. The said performance measures indicate that the proposed CD-PIC gives the superior performances for set point changes and found very much robust in controlling DMFC.

Sign in / Sign up

Export Citation Format

Share Document