scholarly journals Tailored Centrifugal Turbomachinery for Electric Fuel Cell Turbocharger

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Dietmar Filsinger ◽  
Gen Kuwata ◽  
Nobuyuki Ikeya
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Power Density ◽  
Cell System ◽  
Operating Conditions ◽  
Hydrogen Fuel Cell ◽  
Charging System ◽  
Air Supply ◽  
Exhaust Energy ◽  
Compressor Power

Hydrogen fuel cell technology is identified as one option for allowing efficient vehicular propulsion with the least environmental impact on the path to a carbon-free society. Since more than 20 years, IHI is providing charging systems for stationary fuel cell applications and since 2004 for mobile fuel cell applications. The power density of fuel cells substantially increases if the system is pressurized. However, contaminants from fuel cell system components like structural materials, lubricants, adhesives, sealants, and hoses have been shown to affect the performance and durability of fuel cells. Therefore, the charging system that increases the pressure and the power density of the stacks inevitably needs to be oil-free. For this reason, gas bearings are applied to support the rotor of a fuel cell turbocharger. It furthermore comprises a turbine, a compressor, and, on the same shaft, an electric motor. The turbine utilizes the exhaust energy of the stack to support the compressor and hence lower the required electric power of the air supply system. The presented paper provides an overview of the fuel cell turbocharger technology. Detailed performance investigations show that a single-stage compressor with turbine is more efficient compared to a two-stage compressor system with intercooler. The turbine can provide more than 30% of the required compressor power. Hence, it substantially increases the system efficiency. It is also shown that a fixed geometry turbine design is appropriate for most applications. The compressor is of a low specific speed type with a vaneless diffuser. It is optimized for operating conditions of fuel cell systems, which typically require pressure ratios in the range of 3.0.

Dynamic Modelling and Controls of an Air Supply System for In-Flight Proton Exchange Membrane Fuel Cells (PEM-FC)

2007 ◽  
Author(s):  
Lukas P. Barchewitz ◽  
Joerg R. Seume
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Power Density ◽  
Supply System ◽  
Operating Conditions ◽  
Design Parameters ◽  
Radial Turbine ◽  
Air Supply ◽  
Exchange Membrane ◽  
Turbomachinery Design

To cover the increasing demand of on-board electrical power and for further reduction of emissions, the conventional auxiliary power unit (APU) may be replaced by a fuel cell system with an expected efficiency increase of 25% to 50% when compared to start-of-the-art GT-APU. The main components of an in-flight FC system are a compressor-turbine unit, a kerosene reformer, and the fuel cell. Polymer exchange membrane fuel cells (PEM-FC) may be favored because of their currently advanced level of development, their high power density and the available liquid water in the cathode-off gases which can be used as service water on-board. Transient requirements may have significant impact on system design and operating range and will therefore be addressed in this paper. During in-flight operation, air has to be compressed from the ambient to a pressure near standard conditions, which allows the application of state-of-the-art PEM-FC and ensures a constant power density independent from the operating altitude. A centrifugal compressor is chosen for pressurization of the system and is powered by a radial turbine, which allows autonomous operation at cruising altitude without external power. For off-design operation and transients, electric support from the PEM-FC is necessary, see [1]. The radial turbine itself is run by the hot exhaust gases from a post-combustor using the remaining energy in the cathode off-gases. A thorough trade-off between suitable compressor techniques for the air supply system was carried out in [1]. Turbomachinery revealed to be favourable for the PEM air supply system due to their low specific weight and high efficiency. The air supply system resembles the turbocharger for a combustion engine (Fig. 1), which represents a good starting point for a successful integration into the flight environment and further development due to known technology. Based on a turbomachinery design which satisfies the system requirements, the dynamic behavior of the air supply system is analyzed when coupled to the PEM fuel cell. The main focus is on the detection of sensitive system parameters causing system response delay or critical operating conditions. The present paper suggests system features, turbomachinery design parameters and controller types which achieve inherent stability and fast response of the air supply system throughout the entire flight envelope.

Modeling of Coupled Mechanical and Chemical Degradation of the Ionomer Membrane in Polymer Electrolyte Fuel Cells

2018 ◽  
Vol MA2018-01 (32) ◽  
pp. 1992-1992
Author(s):  
Mohamed El Hannach ◽  
Ka Hung Wong ◽  
Yadvinder Singh ◽  
Narinder Singh Khattra ◽  
Erik Kjeang
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Operating Conditions ◽  
Chemical Degradation ◽  
Mechanical Degradation ◽  
Oh Radicals ◽  
List Type ◽  
Hydrogen Fuel Cell ◽  
Hydrogen Fuel ◽  
Power Sources

The hydrogen fuel cell is a promising technology that supports the development of sustainable energy systems and zero emission vehicles. One of the key technical challenges for the use of fuel cells in the transportation sector is the high durability requirements 1–3. One of the key components that control the overall life time of a hydrogen fuel cell is the ionomer membrane that conducts the protons and allows the separation between the anode and the cathode. During fuel cell operation, the membrane is subjected to two categories of degradation: mechanical and chemical. These degradations lead to reduction in the performance, crossover of reactants between anode and cathode and ultimately total failure of the fuel cell. The mechanical degradation occurs when the membrane swells and shrinks under the variation of the local hydration level. This leads to fatigue of the ionomer structure and ultimately irreversible damage. However, under pure mechanical degradation the damage takes a very long time to occur 4,5. Sadeghi et al. 5 observed failure of the membrane after 20,000 of accelerated mechanical stress testing. This translates into a longer lifetime in comparison to what is observed in field operation 6. The chemical degradation on the other hand is caused by the presence of harmful chemicals such as OH radicals that attack the side chains and the main chains of the ionomer 7,8. Such attacks weaken the structural integrity of the membrane and make it prone to severe mechanical damage. Hence understanding the effect of combining both categories of membrane degradation is the key to accurate prediction of the time to failure of the fuel cell. In this work we propose a novel model that represents accurately the structural properties of the membrane and couples the chemical and the mechanical degradations to estimate when the ultimate failure is initiated. The model is based on a network of agglomerated fibrils corresponding to the basic building block of the membrane structure 9–11. The mechanical and chemical properties are defined for each fibril and probability functions are used to evaluate the likelihood of a fibril to break under certain operating conditions. The description of the fundamentals behind the approach will be presented. Two set of simulations will be presented and discussed. The first one corresponding to standard testing scenarios that were used to validate the model. The second set of results will highlight the impact of coupling both degradation mechanisms on the estimation of the failure initiation time. The main strengths of the model and the future development will be discussed as well. T. Sinigaglia, F. Lewiski, M. E. Santos Martins, and J. C. Mairesse Siluk, Int. J. Hydrogen Energy, 42, 24597–24611 (2017). T. Jahnke et al., J. Power Sources, 304, 207–233 (2016). P. Ahmadi and E. Kjeang, Int. J. Energy Res., 714–727 (2016). X. Huang et al., J. Polym. Sci. Part B Polym. Phys., 44, 2346–2357 (2006). A. Sadeghi Alavijeh et al., J. Electrochem. Soc., 162, F1461–F1469 (2015). N. Macauley et al., J. Power Sources, 336, 240–250 (2016). K. H. Wong and E. Kjeang, J. Electrochem. Soc., 161, F823–F832 (2014). K. H. Wong and E. Kjeang, ChemSusChem, 8, 1072–1082 (2015). P.-É. A. Melchy and M. H. Eikerling, J. Phys. Condens. Matter, 27, 325103–6 (2015). J. A. Elliott et al., Soft Matter, 7, 6820 (2011). L. Rubatat, G. Gebel, and O. Diat, Macromolecules, 37, 7772–7783 (2004).

scholarly journals Measurements Based Analysis of the Proton Exchange Membrane Fuel Cell Operation in Transient State and Power of Own Needs

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 498
Author(s):  
Andrzej Wilk ◽  
Daniel Węcel
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Transient State ◽  
Experimental Tests ◽  
Cell System ◽  
Proton Exchange ◽  
Operating Conditions ◽  
Variable Load ◽  
Exchange Membrane

Currently, fuel cells are increasingly used in industrial installations, means of transport, and household applications as a source of electricity and heat. The paper presents the results of experimental tests of a Proton Exchange Membrane Fuel Cell (PEMFC) at variable load, which characterizes the cell’s operation in real installations. A detailed analysis of the power needed for operation fuel cell auxiliary devices (own needs power) was carried out. An analysis of net and gross efficiency was carried out in various operating conditions of the device. The measurements made show changes in the performance of the fuel cell during step changing or smooth changing of an electric load. Load was carried out as a change in the current or a change in the resistance of the receiver. The analysis covered the times of reaching steady states and the efficiency of the fuel cell system taking into account auxiliary devices. In the final part of the article, an analysis was made of the influence of the fuel cell duration of use on obtained parameters. The analysis of the measurement results will allow determination of the possibility of using fuel cells in installations with a rapidly changing load profile and indicate possible solutions to improve the performance of the installation.

Optimization of the Operating Parameters of a Proton Exchange Membrane Fuel Cell for Maximum Power Density

2005 ◽  
Vol 2 (2) ◽  
pp. 121-135 ◽  
Author(s):  
A. Mawardi ◽  
F. Yang ◽  
R. Pitchumani
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Power Density ◽  
Proton Exchange Membrane ◽  
Proton Exchange ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Design Parameters ◽  
Membrane Thickness ◽  
Exchange Membrane

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.

Computational Analysis of Heat Transfer in Air-Cooled Fuel Cells

2011 ◽  
Author(s):  
S. Shahsavari ◽  
M. Bahrami ◽  
E. Kjeang
Keyword(s):  
Heat Transfer ◽  
Fuel Cells ◽  
Fuel Cell ◽  
Temperature Distribution ◽  
Proton Exchange Membrane ◽  
Gas Diffusion ◽  
Cell System ◽  
Proton Exchange ◽  
Operating Conditions ◽  
Heat Management

Temperature distribution in a fuel cell significantly affects the performance and efficiency of the fuel cell system. Particularly, in low temperature fuel cells, improvement of the system requires addressing the heat management issues, which reveals the importance of developing thermal models. In this study, a 3D numerical thermal model is presented to analyze heat transfer and predict the temperature distribution in air-cooled proton exchange membrane fuel cells (PEMFC). In the modeled fuel cell stack, forced air flow supplies oxidant as well as cooling. Conservation equations of mass, momentum, and energy are solved in the oxidant channel, whereas energy equation is solved in the entire domain, including the gas diffusion layers (GDLs) and separator plates, which play a significant role in heat transfer. A parametric study is done to investigate the effect of various operating conditions on maximum cell temperature. The results are further validated with experiment. This model provides a theoretical foundation for thermal analysis of air-cooled stacks, where temperature non-uniformity is high and thermal management and stack cooling is a significant engineering challenge.

Experimental and Theoretical Performance Analysis of a High Temperature PEM Fuel Cell Fed With LPG Using a Compact Steam Reformer

2011 ◽  
Author(s):  
Nicola Zuliani ◽  
Rodolfo Taccani ◽  
Robert Radu
Keyword(s):  
High Temperature ◽  
Fuel Cell ◽  
Cell System ◽  
Operating Conditions ◽  
Steam Reformer ◽  
Fuel Cell Performance ◽  
Fuel Processor ◽  
Balance Of Plant ◽  
Energy Balances ◽  
High Temperature Pem

High temperature PEM (HTPEM) fuel cell based on polybenzimidazole polymer (PBI) and phosphoric acid, can be operated at temperature between 120°C and 180°C. Reactants humidification is not required and CO content up to 1% in fuel can be tolerated, affecting only marginally performance. This is what makes HTPEM fuel cells very attractive, as low quality reformed hydrogen can be used and water management problems are avoided. This paper aims to present the preliminary experimental results obtained on a HTPEM fuel cell fed with LPG using a compact steam reformer. The analysis focus on the reformer start up transient, on the influence of the steam to carbon ratio on reformate CO content and on the single fuel cell performance at different operating conditions. By analyzing the mass and energy balances of the fuel processor, fuel cell system, and balance-of-plant, a previously developed system simulation model has been used to provide critical assessment on the conversion efficiency for a 1 kWel system. The current study attempts to extend the previously published analyses of integrated HTPEM fuel cell systems.

The Resistive Properties of Proton Exchange Membrane Fuel Cells With Stainless Steel Bipolar Plates

2010 ◽  
Vol 7 (4) ◽  
Author(s):  
Shuo-Jen Lee ◽  
Kung-Ting Yang ◽  
Yu-Ming Lee ◽  
Chi-Yuan Lee
Keyword(s):  
Stainless Steel ◽  
Fuel Cells ◽  
Fuel Cell ◽  
Single Cells ◽  
Operating Conditions ◽  
Pure Oxygen ◽  
Bipolar Plates ◽  
Transfer Resistance ◽  
Treated Cell ◽  
Ohmic Resistance

In this research, electrochemical impedance spectroscopy is employed to monitor the resistance of a fuel cell during operation with different operating conditions and different materials for the bipolar plates. The operating condition variables are cell humidity, pure oxygen or air as oxidizer, and current density. Three groups of single cells were tested: a graphite cell, a stainless steel cell (treated and original), and a thin, small, treated stainless steel cell. A treated cell here means using an electrochemical treatment to improve bipolar plate anticorrosion capability. From the results, the ohmic resistance of a fully humidified treated stainless steel fuel cell is 0.28 Ω cm2. Under the same operating conditions, the ohmic resistance of the graphite and the original fuel cell are each 0.1 Ω cm2 and that of the small treated cell is 0.3 Ω cm2. Cell humidity has a greater influence on resistance than does the choice of oxidizer; furthermore, resistance variation due to humidity effects is more serious with air support. From the above results, fuel cells fundamental phenomenon such as ohmic resistance, charge transfer resistance, and mass transport resistance under different operating conditions could be evaluated.

Theoretical Analysis on the Autothermal Reforming Process of Ethanol as Fuel for a Proton Exchange Membrane Fuel Cell System

2006 ◽  
Vol 4 (4) ◽  
pp. 468-473 ◽  
Author(s):  
Alessandra Perna
Keyword(s):  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Pem Fuel Cell ◽  
Cell System ◽  
Autothermal Reforming ◽  
Proton Exchange ◽  
Operating Conditions ◽  
Hydrogen Yield ◽  
Fuel Cell System ◽  
Exchange Membrane

The purpose of this work is to investigate, by a thermodynamic analysis, the effects of the process variables on the performance of an autothermal reforming (ATR)-based fuel processor, operating on ethanol as fuel, integrated into an overall proton exchange membrane (PEM) fuel cell system. This analysis has been carried out finding the better operating conditions to maximize hydrogen yield and to minimize CO carbon monoxide production. In order to evaluate the overall efficiency of the system, PEM fuel cell operations have been analyzed by an available parametric model.

scholarly journals Fuel Cell designing with optimal high speed air compressor

2021 ◽  
pp. 29-38
Author(s):  
Nabeel Ahsan ◽  
Mahrukh Mehmood ◽  
Asad A. Zaidi
Keyword(s):  
Fuel Cell ◽  
High Speed ◽  
Proton Exchange Membrane ◽  
Cell System ◽  
Proton Exchange ◽  
Operating Conditions ◽  
Air Compressor ◽  
Different Types ◽  
Input Parameters ◽  
Turbo Compressor

This paper discusses different air management technologies for fuel cell systems. Two different types of compressors are analyzed for Proton-exchange membrane fuel cells (PEMFC). Some important criteria are analyzed thoroughly for the selection of turbo compressor among different types of compressors illustrated with the help of matrix representations. The impacts of various input parameters for Fuel Cell (FC) are also explained thoroughly. Later the numerical modeling of an automobile fuel cell system using a high speed turbo-compressor for air supply is explained. The numerical model incorporates the important input parameters related with air and hydrogen. It also performed energy and mass balances across different components such as pump, fan, heat-exchanger, air compressor and also keeps in consideration the pressure drop across the flow pipes and various mechanical parts. The model is solved to obtain the characteristics of the FC system at different operating conditions. Therefore, it can be concluded that the high speed turbo compressor with a turbo-expander can have significant effects on the overall system power and efficiency.

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