Optimization of PEM Fuel Cell System Using Dynamic Model

2010 ◽  
Vol 26-28 ◽  
pp. 1019-1026
Author(s):  
Dong Ji Xuan ◽  
Zhen Zhe Li ◽  
Tai Hong Cheng ◽  
Yun De Shen
Keyword(s):  
Fuel Cell ◽  
Dynamic Model ◽  
Output Power ◽  
Power Efficiency ◽  
Cell System ◽  
Optimal Operation ◽  
Maximum Output ◽  
Fuel Cell System ◽  
Operation Condition ◽  
Stack Model

The output power efficiency of the fuel cell system depends on the anode pressure, cathode pressure, temperature, demanded current, air and hydrogen humidity. Thus, it is necessary to determine the optimal operation condition for maximum power efficiency. In this paper, we developed a dynamic model of fuel cell system which contains mass flow model, membrane hydration and electro-chemistry model. Experiments have been performed to evaluate the dynamical Polymer Electrolyte Membrane Fuel Cell (PEMFC) stack model. In order to determine the maximum output power and minimum use of hydrogen in a certain condition, response surface methodology optimization based on the proposed PEMFC stack model is presented. The results provide an effective method to optimize the operation condition under varied situations.

A Dynamic Model of an Atmospheric Solid Oxide Fuel Cell System for Stationary Power Generation

2006 ◽  
Author(s):  
Miriam Kemm ◽  
Azra Selimovic ◽  
Mohsen Assadi
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Dynamic Model ◽  
Transient Behavior ◽  
Cell System ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Fuel Cell System ◽  
System Components ◽  
Solid Part

This paper focuses on the transient behavior of a solid oxide fuel cell system used for stationary power production. Dynamic modelling is applied to identify the characteristic time scales of the system components when introducing a disturbance in operational parameters of the system. The information on the response of the system may be used to specify the control loops needed to manage the changes with respect to safe component operation. The commercial process modelling tool gPROMS is used to perform the system simulations. The component library of the tool is completed with dynamic models of a fuel cell stack and a prereformer. The other components are modelled for steady state operation. For the fuel cell a detailed dynamic model is obtained by writing the constitutive laws for heat transfer in the solid part of the cell and conservation of heat and mass in the air and fuel channels. Comprehensive representation of resistive cell losses, reaction kinetics for the reforming and heat conduction through the solid part of the cell is also included in the model. The prereformer is described as a dynamic pseudo-homogeneous one-dimensional tubular reactor accounting for methane steam reforming and water-gas shift reaction. The differences in the transient behavior of the system components and their interaction are investigated under load changes and feed disturbances.

Optimization of a PEM Fuel Cell System for Low-Speed Hybrid Electric Vehicles

2006 ◽  
Author(s):  
Jeffrey D. Wishart ◽  
Zuomin Dong ◽  
Marc M. Secanell
Keyword(s):  
Fuel Cell ◽  
Pem Fuel Cell ◽  
Load Cycle ◽  
Cell System ◽  
Operating Conditions ◽  
System Model ◽  
Fuel Cell System ◽  
Vehicle Model ◽  
Low Speed ◽  
Stack Model

Design optimization is performed by presenting a systematic method to obtain the optimal operating conditions of a Proton Exchange Membrane (PEM) fuel cell system targeted towards a vehicular application. The fuel cell stack model is a modified version of the semi-empirical model introduced by researchers at the Royal Military College of Canada and one that is widely used by industry. Empirical data obtained from tests of PEM fuel cell stacks are used to determine the empirical parameters of the fuel cell performance model. Based on this stack model, a fuel cell system model is built in MATLAB. Included in the system model are heat transfer and gas flow considerations and the associated Balance of Plant (BOP) components. The modified ADVISOR vehicle simulation tool is used to integrate the New York City Cycle (NYCC) drive cycle and vehicle model to determine the power requirements and hence the load cycle of the fuel cell system for a low-speed fuel cell hybrid electric vehicle (LSFCHEV). The optimization of the powerplant of this vehicle type is unique. The vehicle model has been developed in the work to describe the characteristics and performance of an electric scooter, a simple low-speed vehicle (LSV). The net output power and system exergetic efficiency of the system are maximized for various system operating conditions using the weighted objective function based on the load cycle requirement. The method is based on the coupling of the fuel cell system model with three optimization algorithms (a) sequential quadratic programming (SQP); (b) simulated annealing (SA); and (c) genetic algorithm (GA). The results of the optimization provide useful information that will be used in future study on control algorithms for LSFCHEVs. This study facilitates research on more complex fuel cell system modeling and optimization, and provides a basis for experimentation to verify the fuel cell system model.

Investigation of a Novel Reciprocating Compression Reformer for Use in Solid Oxide Fuel Cell Systems

2003 ◽  
Author(s):  
Anthony N. Zinn ◽  
Todd H. Gardner ◽  
David A. Berry ◽  
Robert E. James ◽  
Dushyant Shekhawat
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Cell System ◽  
Optimal Operation ◽  
Solid Oxide ◽  
Phase Reaction ◽  
Oxide Fuel ◽  
Carbon Formation ◽  
Fuel Cell System ◽  
Cell Systems

A novel reciprocating compression device has been investigated as a non-catalytic natural gas reformer for solid oxide fuel cell systems. The reciprocating compression reformer is a potential improvement over current reforming technology for select applications due to its high degree of heat integration, its homogenous gas phase reaction environment, and its ability to co-produce shaft work. Performance modeling of the system was conducted to understand component integration and operational characteristics. The reformer was modeled by utilizing GRI mech. in tandem with CHEMKIN. The fuel cell was modeled as an equilibrium reactor assuming constant fuel utilization. The effect on the reformer and the reformer – fuel cell system efficiencies and exit gas concentrations was examined over a range of relative air-to-fuel ratios, 0.2 to 1.0, and at compression ratios of 50 and 100. Results from this study indicate that the reformer – fuel cell system could approach 50% efficiency, if run at low relative air-to-fuel ratios (0.3 to 0.5). With higher air-to-fuel ratios, system efficiencies were shown to continuously decline due to a decrease in the quality of synthesis gas provided to the fuel cell (i.e. more power being produced by the reformer). Optimal operation of the system has been shown to occur at a relative air-to-fuel ratio of approximately 0.775 and to be nearly independent of the compression ratio in the reciprocating compression reformer. Higher efficiencies may be obtained at lower relative air-to-fuel ratios; however, operation below this point may lead to excessive carbon formation as determined from an equilibrium carbon formation analysis.

A Dynamic Model for a Closed-Loop Continuous Energy System Using Solar Power

2006 ◽  
Author(s):  
Bradford M. Culwell ◽  
Shripad T. Revankar ◽  
Radhika Kotha
Keyword(s):  
Fuel Cell ◽  
Solar Energy ◽  
Dynamic Model ◽  
Closed Loop ◽  
Solar Power ◽  
Cell System ◽  
Solar Array ◽  
Fuel Cell System ◽  
Power Sources ◽  
Regenerative Fuel Cell

One key advantage of solar power over more traditional power sources is its modular nature, allowing it to be used in remote locations or as a supplementary source of power. Recent studies show fuel cell technology as a good means of providing a continuous supply of electricity from a solar array, eliminating drawbacks caused by solar energy's cyclical nature. The high power density of such a system makes it ideal for use in areas such as unmanned aerial vehicles and space exploration. Due to the complexity and relatively high initial cost of current fuel cells, however, optimization of such a system is critical. This paper examines a dynamic model of a solar regenerative fuel cell system built in MATLAB Simulink. The system uses a polymer electrolyte membrane (PEM) fuel cell, running on stored hydrogen and oxygen, to produce power when solar energy is insufficient. It uses a PEM based electrolyzer to produce hydrogen and oxygen from water when solar energy exceeds demand. The mathematical model includes modules for each component, including solar cells, fuel cell, electrolyzer, and auxiliary systems. Models were built based on fundamental physics to the extent practical. The individual modules were first tested for their performances and then were integrated to form an integrated solar powered regenerative fuel cell system. The simulations were carried out for a day and night cycle and the results show that the closed loop system can be operated providing continuous supply of electric power.

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