Optimum Design and Performance Simulation of a Multi-device Integrated System Based on a Proton Exchange Membrane Fuel Cell

2022 ◽  
pp. 1-33
Author(s):  
Xiuqin Zhang ◽  
Wentao Cheng ◽  
Qiubao Lin ◽  
Longquan Wu ◽  
Junyi Wang ◽  
...  

Abstract Proton exchange membrane fuel cells (PEMFCs) based on syngas are a promising technology for electric vehicle applications. To increase the fuel conversion efficiency, the low-temperature waste heat from the PEMFC is absorbed by a refrigerator. The absorption refrigerator provides cool air for the interior space of the vehicle. Between finishing the steam reforming reaction and flowing into the fuel cell, the gases release heat continuously. A Brayton engine is introduced to absorb heat and provide a useful power output. A novel thermodynamic model of the integrated system of the PEMFC, refrigerator, and Brayton engine is established. Expressions for the power output and efficiency of the integrated system are derived. The effects of some key parameters are discussed in detail to attain optimum performance of the integrated system. The simulation results show that when the syngas consumption rate is 4.0 × 10−5 mol s−1cm−2, the integrated system operates in an optimum state, and the product of the efficiency and power density reaches a maximum. In this case, the efficiency and power density of the integrated system are 0.28 and 0.96 J s−1 cm−2, respectively, which are 46% higher than those of a PEMFC.

2021 ◽  
Vol 13 (3) ◽  
pp. 1218
Author(s):  
Sharjeel Ashraf Ansari ◽  
Mustafa Khalid ◽  
Khurram Kamal ◽  
Tahir Abdul Hussain Ratlamwala ◽  
Ghulam Hussain ◽  
...  

The proton exchange membrane fuel cell (PEMFC) is the fastest growing fuel cell technology on the market. Due to their sustainable nature, PEMFCs are widely adopted as a renewable energy resource. Fabricating a PEMFC is a costly process; hence, mathematical modeling and simulations are necessary in order to fully optimize its performance. Alongside this, the feasibility of a waste heat recovery system based on the organic Rankine cycle is also studied and power generation for different operating conditions is presented. The fuel cell produces a power output of 1198 W at a current of 24A. It has 50% efficiency and hence produces an equal amount of waste heat. That waste heat is used to drive an organic Rankine cycle (ORC), which in turn produces an additional 428 W of power at 35% efficiency. The total extracted power hence stands at 1626 W. MATLAB/Simulink R2016a is used for modeling both the fuel cell and the organic Rankine cycle.


Author(s):  
Utku Gulan ◽  
Hasmet Turkoglu ◽  
Irfan Ar

In this study, the fluid flow and cell performance in cathode side of a proton exchange membrane (PEM) fuel cell were numerically analyzed. The problem domain consists of cathode gas channel, cathode gas diffusion layer, and cathode catalyst layer. The equations governing the motion of air, concentration of oxygen, and electrochemical reactions were numerically solved. A computer program was developed based on control volume method and SIMPLE algorithm. The mathematical model and program developed were tested by comparing the results of numerical simulations with the results from literature. Simulations were performed for different values of inlet Reynolds number and inlet oxygen mole fraction at different operation temperatures. Using the results of these simulations, the effects of these parameters on the flow, oxygen concentration distribution, current density and power density were analyzed. The simulations showed that the oxygen concentration in the catalyst layer increases with increasing Reynolds number and hence the current density and power density of the PEM fuel cell also increases. Analysis of the data obtained from simulations also shows that current density and power density of the PEM fuel cell increases with increasing operation temperature. It is also observed that increasing the inlet oxygen mole fraction increases the current density and power density.


2005 ◽  
Vol 2 (4) ◽  
pp. 263-267 ◽  
Author(s):  
Darrell D. Massie ◽  
Daisie D. Boettner ◽  
Cheryl A. Massie

As part of a one-year Department of Defense demonstration project, proton exchange membrane fuel cell systems have been installed at three residences to provide electrical power and waste heat for domestic hot water and space heating. The 5kW capacity fuel cells operate on reformed natural gas. These systems operate at preset levels providing power to the residence and to the utility grid. During grid outages, the residential power source is disconnected from the grid and the fuel cell system operates in standby mode to provide power to critical loads in the residence. This paper describes lessons learned from installation and operation of these fuel cell systems in existing residences. Issues associated with installation of a fuel cell system for combined heat and power focus primarily on fuel cell siting, plumbing external to the fuel cell unit required to support heat recovery, and line connections between the fuel cell unit and the home interior for natural gas, water, electricity, and communications. Operational considerations of the fuel cell system are linked to heat recovery system design and conditions required for adequate flow of natural gas, air, water, and system communications. Based on actual experience with these systems in a residential setting, proper system design, component installation, and sustainment of required flows are essential for the fuel cell system to provide reliable power and waste heat.


Author(s):  
Saher Al Shakhshir ◽  
Xin Gao ◽  
Torsten Berning

Abstract In a previous numerical study on heat and mass transfer in air-cooled proton exchange membrane fuel cells, it was found that the performance is limited by heat transfer to the cathode side air stream that serves as a coolant, and it was proposed to place a turbulence grid before the cathode inlet in order to induce a mixing effect to the air and thereby improve the heat transfer and ultimately increase the limiting current and maximum power density. The current work summarizes experiments with different turbulence grids which varied in terms of their pore size, grid thickness, rib width, angle of the pores, and the distance between the grid and the cathode inlet. For all grids tested in this study, the limiting current density of a Ballard Mark 1020 ACS stack was increased by 20%. The single most important parameter was the distance between the turbulence grid and the cathode inlet, and it should be within 5 mm. For the best grid tested, the fuel cell stack voltage and thus the efficiency were increased by up to 20%. The power density was increased by more than 30% and further improvements are believed to be possible.


Author(s):  
Torsten Berning

Abstract A numerical analysis of an air-cooled proton exchange membrane fuel cell (PEMFC) has been conducted. The model utilizes the Eulerian multi-phase approach to predict the occurrence and transport of liquid water inside the cell. It is assumed that all the waste heat must be carried out of the fuel cell with the excess air which leads to a strong temperature increase of the air stream. The results suggest that the performance of these fuel cells is limited by membrane overheating which is ultimately caused by the limited heat transfer to the laminar air stream. A proposed remedy is the placement of a turbulence grid before such a fuel cell stack to enhance the heat transfer and increase the fuel cell performance.


2005 ◽  
Vol 2 (2) ◽  
pp. 121-135 ◽  
Author(s):  
A. Mawardi ◽  
F. Yang ◽  
R. Pitchumani

The performance of fuel cells can be significantly improved by using optimum operating conditions that maximize the power density subject to constraints. Despite its significance, relatively scant work is reported in the open literature on the model-assisted optimization of fuel cells. In this paper, a methodology for model-based optimization is presented by considering a one-dimensional nonisothermal description of a fuel cell operating on reformate feed. The numerical model is coupled with a continuous search simulated annealing optimization scheme to determine the optimum solutions for selected process constraints. Optimization results are presented over a range of fuel cell design parameters to assess the effects of membrane thickness, electrode thickness, constraint values, and CO concentration on the optimum operating conditions.


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