Exergy analysis of a polymer fuel cell and identification of its optimum operating conditions using improved Farmland Fertility Optimization

Energy ◽  
2021 ◽  
Vol 216 ◽  
pp. 119264
Author(s):  
Xiaohui Lu ◽  
Bing Li ◽  
Lin Guo ◽  
Peifang Wang ◽  
Nasser Yousefi
Keyword(s):  
Fuel Cell ◽  
Exergy Analysis ◽  
Operating Conditions ◽  
Optimum Operating

Exergy Analysis of a Combined Power and Refrigeration Thermodynamic Cycle Driven by a Solar Heat Source

2003 ◽  
Vol 125 (1) ◽  
pp. 55-60 ◽  
Author(s):  
Afif Akel Hasan ◽  
D. Y. Goswami
Keyword(s):  
Heat Source ◽  
Exergy Analysis ◽  
Thermodynamic Cycle ◽  
Exergy Efficiency ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Water Mixture ◽  
Exergy Destruction ◽  
Ammonia Water ◽  
Solar Heat

Exergy thermodynamics is employed to analyze a binary ammonia water mixture thermodynamic cycle that produces both power and refrigeration. The analysis includes exergy destruction for each component in the cycle as well as the first law and exergy efficiencies of the cycle. The optimum operating conditions are established by maximizing the cycle exergy efficiency for the case of a solar heat source. Performance of the cycle over a range of heat source temperatures of 320–460°K was investigated. It is found that increasing the heat source temperature does not necessarily produce higher exergy efficiency, as is the case for first law efficiency. The largest exergy destruction occurs in the absorber, while little exergy destruction takes place in the boiler.

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.

Designing Solid Oxide Fuel Cell Gas Turbine Hybrid Systems Using Exergy Analysis

2006 ◽  
Author(s):  
K. J. Bosch ◽  
N. Woudstra ◽  
K. V. van der Nat
Keyword(s):  
Fuel Cell ◽  
Natural Gas ◽  
Solid Oxide Fuel Cell ◽  
Gas Turbine ◽  
Hybrid Systems ◽  
Exergy Analysis ◽  
Operating Conditions ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Exergy Losses

In conventional gas turbine systems combustion results in high exergy losses (∼30%) of fuel exergy input. Replacing the combustor with a high temperature fuel cell, like the Solid Oxide Fuel Cell (SOFC), will significantly reduce these exergy losses. As the SOFC electrochemically converts the natural gas, exergy losses are far lower (∼10%) compared to combustion. Natural gas entering a SOFC system has to be reformed first to hydrogen and carbon monoxide by steam reforming. Here it is chosen to use the heat generated by the fuel cell to drive the endothermic reforming reactions: internal reforming. The SOFC-GT system has the advantage that both fuel cell and gas turbine technology contribute to power production. In earlier work [1] several fuel cell system configurations with PEMFC, MCFC or SOFC, were analyzed studying the exergy flows. Here is focused on the SOFC-GT configuration, to get a detailed understanding of the exergy flows and losses through all individual components. Several configurations, combining the SOFC with the GT are possible. The selected operating conditions should prevent carbon deposition. Systems studies are performed to get more insight in the exergy losses in these combined systems. Exergy analysis facilitates the search for the high efficient SOFC-GT hybrid systems. Using exergy analysis, several useful configurations are found. Exergy losses are minimized by varying pressure ratio and turbine inlet temperature. Sensitivity studies, of equivalent cell resistance and fuel cell temperature, show that total system exergy efficiencies of more than 80% are conceivable, without using a bottoming cycle.

Exergy Analysis for the Performance of Solar Collectors

1983 ◽  
Vol 105 (2) ◽  
pp. 163-167 ◽  
Author(s):  
M. Fujiwara
Keyword(s):  
Performance Evaluation ◽  
Pressure Drop ◽  
Exergy Analysis ◽  
Operating Conditions ◽  
Exergy Loss ◽  
Optimum Operating ◽  
Solar Collectors ◽  
Optimum Control ◽  
Friction Process ◽  
And Performance

The optimum control and performance evaluation of solar collectors are analyzed from the standpoint of exergy. The pressure drop inside the collector is introduced to the analysis using the Hottel-Whillier model. By treating the friction process as exergy loss, the optimum operating conditions are presented in a simple statement. The maximum capability of collectors is determined and expressed by a relationship among the collector parameters and the environment in which they operates.

scholarly journals Performance Analysis of a Hybrid System Consisting of a Molten Carbonate Direct Carbon Fuel Cell and an Absorption Refrigerator

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 357 ◽  
Author(s):  
Houcheng Zhang ◽  
Jiatang Wang ◽  
Jiapei Zhao ◽  
Fu Wang ◽  
He Miao ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Hybrid System ◽  
Current Density ◽  
System Performance ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Molten Carbonate ◽  
Direct Carbon Fuel Cell ◽  
Operating Current ◽  
Absorption Refrigerator

By integrating an Absorption Refrigerator (AR), a new hybrid system model is established to reuse the waste heat from a Molten Carbonate Direct Carbon Fuel Cell (MCDCFC) for additional cooling production. Various irreversible losses in each element of the system are numerically described. The operating current density span of the MCDCFC that allows the AR to work is derived. Under different operating conditions, the mathematical expressions for equivalently evaluating the hybrid system performance are derived. In comparison with the stand-alone MCDCFC, the maximum attainable power density of the proposed system and its corresponding efficiency are increased by 5.8% and 6.8%, respectively. The generic performance features and optimum operating regions of the proposed system are demonstrated. A number of sensitivity analyses are performed to study the dependences of the proposed system performance on some physical parameters and operating conditions such as operating temperature, operating current density, and pressure of the MCDCFC, cyclic working fluid internal irreversibility inside the AR, thermodynamic losses related parameters and the anode thickness of the MCDCFC. The obtained results may offer some new insights into the performance improvement of an MCDCFC through a reasonable heat management methodology.

scholarly journals Flexible Five-in-One Microsensor for Real-Time Wireless Microscopic Diagnosis inside Electric Motorcycle Fuel Cell Stack Range Extender

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 103
Author(s):  
Chi-Yuan Lee ◽  
Chia-Hung Chen ◽  
Ti-Ju Lee ◽  
John-Shong Cheong ◽  
Yi-Cheng Liu ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Real Time ◽  
Bipolar Plate ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Strong Impact ◽  
Energy Regulation ◽  
Fuel Cell Stack ◽  
Range Extender ◽  
Microscopic Diagnosis

The focus of research and development on electric motorcycle range extender are system integration and energy regulation and management but the present fuel cell stack range extender still has defects, such as large volume, heavy weight and high cost. Its volume and weight will have a strong impact on the endurance of electric motorcycle. The bipolar plate takes most volume and weight of a proton exchange membrane fuel cell (PEMFC) stack and it is the key component influencing the overall power density and cost. Therefore, how to thin and lighten the bipolar plate and to enhance the performance and life of PEMFC stack is an urgent research subject to be solved for the moment and will be the key to whether the PEMFC stack range extender can be put in the electric motorcycle or not. In addition, the internal temperature, humidity, flow, voltage and current in the operation of PEMFC stack will influence its performance and life and the overall performance and life of fuel cell stack will be directly influenced by different external operating conditions. As nonuniform distribution of temperature, humidity, flow, voltage and current will occur in various regions inside the fuel cell stack, this study will use micro-electro-mechanical systems (MEMS) technology to develop a flexible five-in-one microsensor, which is embedded in the PEMFC stack range extender for real-time wireless microscopic diagnosis and the reliability test is performed, so that the actual operating condition inside the fuel cell stack range extender can be mastered instantly and correctly and the internal information is fed back instantly, the fuel cell stack range extender control system can be modified to the optimum operating parameters immediately, so as to enhance the performance and prolong the lifetime effectively.

scholarly journals Performance Analysis of the Perhydro-Dibenzyl-Toluene Dehydrogenation System—A Simulation Study

2021 ◽  
Vol 13 (11) ◽  
pp. 6490
Author(s):  
Farea Asif ◽  
Muhammad Haris Hamayun ◽  
Murid Hussain ◽  
Arif Hussain ◽  
Ibrahim M. Maafa ◽  
...  
Keyword(s):  
Exergy Analysis ◽  
Process Integration ◽  
Operating Conditions ◽  
Energy Resources ◽  
Optimum Operating ◽  
Operational Conditions ◽  
Aspen Hysys ◽  
System A ◽  
Analysis Strategy ◽  
And Storage

The depletion of conventional energy resources has drawn the world’s attention towards the use of alternate energy resources, which are not only efficient but sustainable as well. For this purpose, hydrogen is considered the fuel of the future. Liquid organic hydrogen carriers (LOHCs) have proved themselves as a potential option for the release and storage of hydrogen. The present study is aimed to analyze the performance of the perhydro-dibenzyl-toluene (PDBT) dehydrogenation system, for the release of hydrogen, under various operational conditions, i.e., temperature range of 270–320 °C, pressure range of 1–3 bar, and various platinum/palladium-based catalysts. For the operational system, the optimum operating conditions selected are 320 °C and 2 bar, and 2 wt. % Pt/Al2O3 as a suitable catalyst. The configuration is analyzed based on exergy analysis i.e., % exergy efficiency, and exergy destruction rate (kW), and two optimization strategies are developed using principles of process integration. Based on exergy analysis, strategy # 2, where the product’s heat is utilized to preheat the feed, and utilities consumption is minimized, is selected as the most suitable option for the dehydrogenation system. The process is simulated and optimized using Aspen HYSYS® V10.

Mitigation of Carbon Formation During Autothermal Reforming of Biodiesel for Solid Oxide Fuel Cell Applications

2012 ◽  
Author(s):  
J. Lin ◽  
M. R. Walluk ◽  
D. F. Smith ◽  
T. A. Trabold
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Acoustic Method ◽  
Operating Conditions ◽  
Solid Oxide ◽  
Optimum Operating ◽  
Experimental Investigations ◽  
Hydrogen Yield ◽  
Oxide Fuel ◽  
Carbon Formation

Biodiesel is considered as a renewable hydrogen source for solid oxide fuel cells (SOFCs). This study contributes to a fundamental understanding of biodiesel auto-thermal reforming (ATR), which has not yet been widely explored in the open literature. Ultra-lower sulfur diesel (ULSD) ATR is established as a baseline for this analysis. Solid carbon formation during AT R has been recognized as a primary degradation mode in solid oxide fuel cell-based auxiliary power unit systems in transportation applications, but is difficult to detect and control. To overcome these challenges, this work applies a direct photo-acoustic method to analyze carbon dynamic evolutions and quantify the carbon formation in a single-tube reformer under various operating conditions (temperature, steam/carbon ratio, and oxygen/carbon ratio). The key objective is to locate the optimum operating environment for biodiesel ATR with carbon-free deposition and peak hydrogen yield. Thermodynamic analysis based on the method of total Gibbs free energy minimization is used to evaluate the equilibrium reformate compositions. The experimental investigations complimented with the theoretical analysis of biodiesel ATR helps effectively optimize the onboard reforming conditions.

scholarly journals Optimum Alkaline Electrolyzer-Proton Exchange Membrane Fuel Cell Coupling in a Residential Solar Stand-Alone Power System

2011 ◽  
Vol 2011 ◽  
pp. 1-13 ◽  
Author(s):  
Hany A. Khater ◽  
Amr A. Abdelraouf ◽  
Mohamed H. Beshr
Keyword(s):  
Fuel Cell ◽  
Power System ◽  
Proton Exchange Membrane ◽  
Operating Temperature ◽  
Proton Exchange ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Optimum Conditions ◽  
Operational Life ◽  
Exchange Membrane

Modeling of an alkaline electrolyzer and a proton exchange membrane fuel cell (PEMFC) is presented. Also, a parametric study is performed for both components in order to determine the effect of variable operating conditions on their performance. The aim of this study is to determine the optimum operating conditions when the electrolyzer and the PEMFC are coupled together as part of a residential solar powered stand-alone power system comprising photovoltaic (PV) arrays, an alkaline electrolyzer, storage tanks, a secondary battery, and a PEMFC. The optimum conditions are determined based on an economic study which is performed to determine the cost of electricity (COE) produced from this system so as to determine the lowest possible COE. All of the calculations are performed using a computer code developed by using MATLAB. The code is designed so that any user can easily change the data concerning the location of the system or the working parameters of any of the system's components to estimate the performance of a modified system. Cairo city in Egypt was used as the place at which the output of the system will be determined. It was found that the optimum operating temperature of the electrolyzer is 25∘C. Also, the optimum coupling pressure of the electrolyzer and the PEMFC is 4 bars. The operating temperature of the PEMFC had a slight effect on its performance while an optimum current density of 400 mA/cm2 was detected. By operating the fuel cell at optimum conditions, its efficiency was found to be 64.66% with a need of 0.5168 Nm3 (Nm3 is a m3 measured at temperature of 0∘C and pressure of 1 bar) of hydrogen to produce 1 kWh of electricity while its cogeneration efficiency was found to be 84.34%. The COE of the system was found to be 49 cents/kWh, at an overall efficiency of 9.87%, for an operational life of 20 years.

Performance Simulation of a Hybrid Micro Gas Turbine Fuel Cell System Based on Existing Components

2011 ◽  
Author(s):  
D. P. Bakalis ◽  
A. G. Stamatis
Keyword(s):  
Fuel Cell ◽  
Gas Turbine ◽  
System Performance ◽  
Cell System ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Utilization Factor ◽  
Micro Gas Turbine ◽  
Wide Range ◽  
Using Data

The objective of this work is the development of a simulation model for a hybrid Solid Oxide Fuel Cell (SOFC)/Micro Gas Turbine (MGT) system, flexible and robust enough, capable to predict the system performance under various operating conditions. The hybrid system consists of a high temperature SOFC, based on a tubular configuration developed by Siemens Power Generation Inc, and a recuperated small gas turbine (GT) validated using data for the Capstone C30. The design and off-design performance of the system is examined by means of performance maps. Moreover, operating parameters such as fuel utilization factor, steam to carbon ratio and current density are varied over a wide range and the influence on system performance is studied. The optimum operating conditions are discussed with regard to overall system performance under part load operation. The results show that high electrical efficiencies can be achieved making these systems appropriate for distributed generation applications.

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