scholarly journals A Thermodynamic Analysis of an Air-Cooled Proton Exchange Membrane Fuel Cell Operated in Different Climate Regions

Energies ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2611 ◽  
Author(s):  
Torsten Berning ◽  
Søren Knudsen Kær

A fundamental thermodynamic analysis of an air-cooled fuel cell, where the reactant air stream is also the coolant stream, is presented. The adiabatic cell temperature of such a fuel cell is calculated in a similar way as the adiabatic flame temperature in a combustion process. Diagrams that show the dependency of the cathode outlet temperature, the stoichiometric flow ratio and the operating cell voltage are developed. These diagrams can help fuel cell manufacturers to identify a suitable blower and a suitable operating regime for their fuel cell stacks. It is found that for standard conditions, reasonable cell temperatures are obtained for cathode stoichiometric flow ratios of ξ = 50 and higher, which is in very good agreement with manufacturer’s recommendations. Under very cold ambient conditions, the suggested stoichiometric flow ratio is only in the range of ξ = 20 in order to obtain a useful fuel cell operating temperature. The outside relative humidity only plays a role at ambient temperatures above 40 °C, and the predicted stoichiometric flow ratios should be above ξ = 70 in this region. From a thermodynamic perspective, it is suggested that the adiabatic outlet temperature is a suitable definition of the fuel cell operating temperature.

Energies ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3478 ◽  
Author(s):  
Arne L. Lazar ◽  
Swantje C. Konradt ◽  
Hermann Rottengruber

This work presents an open-source, dynamic, 1D, proton exchange membrane fuel cell model suitable for real-time applications. It estimates the cell voltage based on activation, ohmic and concentration overpotentials and considers water transport through the membrane by means of osmosis, diffusion and hydraulic permeation. Simplified equations reduce the computational load to make it viable for real-time analysis, quick parameter studies and usage in complex systems like complete vehicle models. Two modes of operation for use with or without reference polarization curves allow for a flexible application even without information about cell parameters. The program code is written in MATLAB and provided under the terms and conditions of the Creative Commons Attribution License (CC BY). It is designed to be used inside of a Simulink model, which allows this fuel cell model to be used in a wide variety of 1D simulation platforms by exporting the code as C/C++.


Author(s):  
F. C. Wang ◽  
Y. P. Yang ◽  
H. P. Chang ◽  
Y. W. Ma ◽  
C. W. Huang ◽  
...  

This paper applies robust control strategies to a PEM fuel-cell system. In Part I of this work [17], a PEM fuel cell was described as a two-input-two-output system with the inputs of hydrogen and air flow rates, and the outputs of cell voltage and current. From the responses, system identification techniques were adopted to model the system transfer function matrix. Then adaptive control methods were applied to control the system with encouraging results. In this paper, the H∞ robust control strategy is proposed due to the highly nonlinear and time-varying characteristics of the system. From the results, it is illustrated to be an efficient control method for the fuel cell systems.


Author(s):  
Chen-Chung Chung ◽  
Chiun-Hsun Chen ◽  
Hsiang-Hui Lin ◽  
Yi-Yie Yan

The investigation studies improving PEMFC carbon monoxide by a periodic air dosing. The carbon monoxide in the fuel gas leads to a significant loss in power density due to CO poisoning in the anode. The method involves bleeding air into the anode fuel stream (H2-CO), which contains CO in various concentrations (20, 52.7, 100 ppm). In the transient CO poisoning test, air-bleeding is performed for four different periodic air dosing and cell voltage is fixed at 0.6 V. The result of a dosing of air during 10 sec in intervals of 10 sec is similar to that of continuous air-bleeding except 100 ppm CO. The CO tolerance of the fuel cell and cell performance recovery from poisoning can be improved by air-bleeding.


2010 ◽  
Vol 34-35 ◽  
pp. 92-97
Author(s):  
Rui Quan ◽  
Shu Hai Quan ◽  
Liang Huang

Proton exchange membrane fuel cell(PEMFC) technology has been greatly promoted in recent years, but the fault diagnosis and predictive maintenance are unneglectable issues in practical work. According to the safety and reliability requirement of 60kW automotive fuel cell engine designed by our group, a fault diagnosis method based on T-S fuzzy model which is tuned and optimized thanks to particle swarm optimization is put forward in this paper. Its inputs include voltage, the lowest single cell voltage, current, temperature and air pressure, by setting the output threshold of T-S fuzzy model at 0.85,when the healthy degree and its variety rate are below 0.85 and 0.05 respectively, the flooding fault is distinguished, if the healthy degree is below 0.85 but its variety rate is above 0.05,drying of the proton membrane is on-line diagnosed successfully, which can provide a guidance to its real-time monitoring and optimized control in future.


Author(s):  
Jason B. Siegel ◽  
Denise A. McKay ◽  
Anna G. Stefanopoulou

The operation and accumulation of liquid water within the cell structure of a polymer electrolyte membrane fuel cell (PEMFC) with a dead-ended anode is observed using neutron imaging. The measurements are performed on a single cell with 53 square centimeter active area, Nafion 111-IP membrane and carbon cloth Gas Diffusion Layer (GDL). Even though dry hydrogen is supplied to the anode via pressure regulation, accumulation of liquid water in the anode gas distribution channels was observed for all current densities up to 566 mA cm−2 and 100% cathode humidification. The accumulation of liquid water in the anode channels is followed by a significant voltage drop even if there is no buildup of water in the cathode channels. Anode purges and cathode surges are also used as a diagnostic tool for differentiating between anode and cathode water flooding. The rate of accumulation of anode liquid water, and its impact on the rate of cell voltage drop is shown for a range of temperature, current density, cathode relative humidity and air stoichiometric conditions. Neutron imaging of the water while operating the fuel cell under dead-ended anode conditions offers the opportunity to observe water dynamics and measured cell voltage during large and repreatable transients.


Author(s):  
A. B. Mahmud Hasan ◽  
S. M. Guo ◽  
S. V. Ekkad

The performance of a Proton Exchange Membrane Fuel Cell (PEMFC) using different feeding configurations has been studied. Three bipolar plates, namely serpentine, straight channel and interdigitated designs, were arranged in different combinations for the PEMFC anode and cathode sides. Nine combinations in total were tested under different flow rates, working temperatures and loadings. The cell voltage versus current density and the cell power density versus current density curves were obtained. After operating the PEMFC under high current densities, the cell was split and the water flooding in the feeding channels was visually inspected. Experimental results showed that for different feeding configurations, interdigitated bipolar plate in anode side and serpentine bipolar plate in cathode side had the best performance in terms of cell voltage-current density curve, power density output rate, percentage of flooded area in the feeding channels, the pattern of flooding and the fuel utilization rate.


Author(s):  
Balaji Krishnamurthy ◽  
Hariharan Ramasubramanian

<p class="PaperAbstract">A mathematical model is developed to study the leakage current in a solid oxide fuel cell (SOFC) with a bi-layer electrolyte. The model predicts the variation of leakage current and power density with various design and operating factors of SOFC, namely thickness of the bi-layer electrolyte, operating temperature and operating cell voltage. The interfacial oxygen pressure in SOFC is also studied as a function of the thickness of YSZ layer. Modelling results are compared with experimental data and found to compare well.</p>


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