Fuel Cells and Cogeneration

2005 ◽  
Author(s):  
J. A. R. Parise ◽  
J. V. C. Vargas ◽  
R. Pitanga Marques
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Hybrid Systems ◽  
High Temperatures ◽  
Heat Sources ◽  
Power Cycles ◽  
Thermodynamic Cycles ◽  
Simultaneous Production ◽  
Energy Technologies

Although historically grown as independent energy technologies, fuel cell and cogeneration may adequately work to each other’s benefit. Some fuel cells deliver heat at sufficiently high temperatures, which can be certainly used as heat sources for cogeneration or trigeneration schemes. The paper presents an overview of the innumerable combinations of the simultaneous production, with fuel cells, of (i) heat and power, (ii) cold and electricity, and (iii) cold, heat and electricity, in its multiple varieties. The survey included combined power cycles (also called hybrid systems) where the fuel cell works together with other thermodynamic cycles to produce, with a high fuel-to-electricity efficiency, electricity alone. A large number of cogeneration arrangements are mentioned. Some are described in detail. A brief analysis of benefits and drawbacks of such systems was undertaken. The review was limited to articles published in archival periodicals, proceedings and a few technical reports, theses and books.

Fuel Cells and Cogeneration

2008 ◽  
Vol 5 (3) ◽  
Author(s):  
J. A. R. Parise ◽  
J. V. C. Vargas ◽  
R. Pitanga Marques
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Cell System ◽  
Heat Sources ◽  
Fuel Cell System ◽  
Power Cycles ◽  
Thermodynamic Cycles ◽  
Simultaneous Production ◽  
Energy Technologies ◽  
System Configurations

Although historically grown as independent energy technologies, fuel cell and cogeneration may adequately work to each other’s benefit. Some fuel cells deliver heat at sufficiently high temperatures, which can be certainly used as heat sources for cogeneration or trigeneration schemes. The paper presents an overview of the innumerable fuel cell system configurations for simultaneous production of (i) heat and power, (ii) cooling and electricity, and (iii) cooling, heat, and electricity. The survey includes combined power cycles (also called hybrid systems) where the fuel cell works together with other thermodynamic cycles to produce, with a high fuel-to-electricity efficiency, electricity alone. A large number of cogeneration arrangements are mentioned. Some are described in detail. A brief analysis of benefits and drawbacks of such systems was undertaken. The review was limited to articles published in archival periodicals, proceedings, and a few technical reports, theses, and books.

Fuel-Cell Hybrid Systems to Generate Shipboard Electrical Power

2009 ◽  
Author(s):  
W. J. Sembler ◽  
S. Kumar
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Air Quality ◽  
Hybrid Systems ◽  
Hybrid System ◽  
Cell Hybrid ◽  
Electrical Power ◽  
History Of ◽  
Marine Applications ◽  
Fuel Cell Hybrid

The reduction of shipboard airborne emissions has been receiving increased attention due to the desire to improve air quality and reduce the generation of greenhouse gases. The use of a fuel cell could represent an environmentally friendly way for a ship to generate in-port electrical power that would eliminate the need to operate diesel-driven generators or use shore power. This paper includes a brief description of the various types of fuel cells in use today, together with a review of the history of fuel cells in marine applications. In addition, the results of a feasibility study conducted to evaluate the use of a fuel-cell hybrid system to produce shipboard electrical power are presented.

Performance Analysis on SOFC-HCCI Engine Hybrid System

2012 ◽  
Author(s):  
Sung Ho Park ◽  
Young Duk Lee ◽  
Sang Gyu Kang ◽  
Kook Young Ahn
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Hybrid Systems ◽  
Hybrid System ◽  
Gas Turbines ◽  
Waste Heat ◽  
Metal Catalyst ◽  
Molten Carbonate ◽  
Hcci Engine ◽  
Ci Engines

Fuel cell systems are currently regarded as a promising type of energy conversion system. Various types of fuel cell have been developed and investigated worldwide for portable, automotive, and stationary applications. In particular, in the case of large-scale stationary applications, the high-temperature fuel cells known as the molten carbonate fuel cell (MCFC) and the solid oxide fuel cell (SOFC) have been used as a power source due to their higher efficiency compared to low-temperature fuel cells. Because SOFCs have many advantages, including a high power density, low corrosion, and operability without a metal catalyst, many efforts to develop a SOFC hybrid system have been undertaken. SOFC hybrid systems with a gas turbine or engine show improved system efficiency through their utilization of waste heat and unreacted fuel. Especially, the internal combustion engine has the advantage of robustness, easy maintenance, and a low cost compared to gas turbines, this type is more adaptable for use in a hybrid system with a SOFC. However, the engine should be operated stably at a high air fuel ratio because the SOFC anode exhaust gas has a low fuel concentration. The homogeneous charge compression ignition (HCCI) engine has both the advantages of SI and CI engines. Moreover, the lean burn characteristics of the HCCI engine make it a strong candidate for SOFC hybrid systems. The objective of this work is to develop a novel cycle composed of a SOFC and a HCCI engine. In order to optimize the SOFC-HCCI hybrid system, a system analysis is conducted here using the commercial software Aspen Plus®. The SOFC model is validated with experimental data. The engine model is developed based on an empirical equation that considers the ignition delay time. The performance of the hybrid system is compared with that of a SOFC stand-alone system to confirm the optimization of the system. This study will be useful for the development of a new type of hybrid system which uses a fuel cell and an optimized system.

Simulation of Distributive Generation Using Fuel Cell Hybrid Systems

2006 ◽  
Author(s):  
Brian Wolf ◽  
Shripad Revankar
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Hybrid Systems ◽  
Hybrid System ◽  
Cell Hybrid ◽  
Cell Model ◽  
Initial Step ◽  
Parametric Studies ◽  
Key Issues ◽  
Fuel Cell Hybrid

Fuel cell hybrid technology has the potential to significantly change our current energy infrastructure. Past studies have shown that the combination of fuel cells and turbines can produce power at remarkably high efficiencies with low levels of pollution. The work presented in this paper is an initial step to further development of a hybrid system model. The fuel cell model discussed is used to perform parametric studies to aid in the optimization of a hybrid system. This paper provides an overview of fuel cell hybrid systems and distributive generation. A fuel cell model is implemented in SIMULINK using basic balance equations. Key issues of modeling specifically high temperature fuel cells are discussed along with their transient response and how it may affect the performance of a distributive generation system.

Hydrogen Fuel Cell Technologies for Sustainable Stationary Applications

2021 ◽  
pp. 166-185
Author(s):  
Raluca-Andreea Felseghi ◽  
Florin Badea
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Clean Energy ◽  
Energy Resources ◽  
Hydrogen Fuel Cell ◽  
Hydrogen Fuel ◽  
Renewable Energy Resources ◽  
Energy Technologies ◽  
Cell Technologies ◽  
Main Components

Science has shown that there are two sustainable alternatives to providing energy needs: renewable energy resources and fuel cells-hydrogen-based energy, which will play a complementary role in securing global energy resources. By promoting the use of hydrogen-based energy technologies, as clean energy technologies for stationary applications, at the level of local communities, industrial and commercial communities, research topics in this field will help the practical development of sustainable and clean energy systems. This chapter provides an overview of fuel cells highlighting aspects related to fuel cell short history, the main components and operating principles of fuel cells, the main constructive fuel cell types, and the main ways of powering stationary applications through the hydrogen fuel cell technologies.

High Efficiency SOFC Power Cycles With Indirect Natural Gas Reforming and CO2 Capture

2014 ◽  
Author(s):  
Stefano Campanari ◽  
Matteo Gazzani
Keyword(s):  
Fuel Cells ◽  
High Temperature ◽  
Fuel Cell ◽  
Natural Gas ◽  
Co2 Capture ◽  
Heat Exchangers ◽  
High Hydrogen ◽  
Power Cycles ◽  
Power Cycle ◽  
Natural Gas Reforming

Driven by the search for the highest theoretical efficiency, several studies have investigated in the last years the adoption of fuel cells in the field of power production from natural gas with CO2 capture. Most of the proposed power cycles rely on high temperature fuel cells, namely Solid Oxide Fuel Cells (SOFC) and Molten Carbonate Fuel Cells (MCFC), based on the concept of hybrid fuel cell plus gas turbine cycles. Accordingly, high temperature fuel cells are integrated with a simple or modified Brayton cycle. As far as SOFC are concerned, two main plant solutions can be identified depending on the integration with the natural gas reforming/shift section: (i) systems where natural gas is — partially or totally — internally reformed in the fuel cell and (ii) systems where natural gas is reformed before the fuel cell and the cell is fed with a high hydrogen syngas. In both cases, CO2 can be separated downstream the fuel cell via a range of available technologies, e.g. chemical or physical separation processes, oxy-combustion and cryogenic methods. Following a literature review on very promising plant configurations, this work investigates the advantages and limits of adopting an external natural gas conversion section with respect to the plant efficiency. As a reference plant we considered a power cycle proposed by Adams and Barton [8], whose performance is the highest found in literature for SOFC-based power cycles, with 82% LHV electrical efficiency. It is based on a pre-reforming concept where fuel is reformed ahead the SOFC which thus works with a high hydrogen content fuel. This plant was firstly reproduced considering all the ideal assumptions proposed by the original authors. As second step, the simulations were focused on revising the power cycle, implementing a complete set of assumptions about component losses and more conservative operating conditions about fuel cell voltage, heat exchangers minimum temperature differences, maximum steam temperature, turbomachinery efficiency, component pressure losses and other adjustments. Considering the consequent modifications with respect to the original layout, the net electric efficiency changes to around 66% LHV with nearly complete (95%+) CO2 capture, a still remarkable but less attractive value, while requiring a very complex and demanding heat exchangers network. Detailed results are presented in terms of energy and material balances of the proposed cycles. All the simulations have been carried out with the proprietary code GS, developed by the GECOS group at Politecnico di Milano.

A New Concept for High Temperature Fuel Cell Hybrid Systems Using Supercritical Carbon Dioxide

2009 ◽  
Vol 6 (2) ◽  
Author(s):  
D. Sánchez ◽  
R. Chacartegui ◽  
F. Jiménez-Espadafor ◽  
T. Sánchez
Keyword(s):  
Carbon Dioxide ◽  
Fuel Cells ◽  
High Temperature ◽  
Fuel Cell ◽  
Supercritical Carbon Dioxide ◽  
Hybrid Systems ◽  
Cell Hybrid ◽  
Gas Turbines ◽  
Solid Oxide ◽  
Molten Carbonate

Hybrid power systems based on high temperature fuel cells are a promising technology for the forthcoming distributed power generation market. For the most extended configuration, these systems comprise a fuel cell and a conventional recuperative gas turbine engine bottoming cycle, which recovers waste heat from the cell exhaust and converts it into useful work. The ability of these gas turbines to produce useful work relies strongly on a high fuel cell operating temperature. Thus, if molten carbonate fuel cells or the new generation intermediate temperature solid oxide fuel cells are used, the efficiency and power capacity of the hybrid system decrease dramatically. In this work, carbon dioxide is proposed as the working fluid for a closed supercritical bottoming cycle, which is expected to perform better for intermediate temperature heat recovery applications than the air cycle. Elementary fuel cell lumped-volume models for both solid oxide and molten carbonate are used in conjunction with a Brayton cycle thermodynamic simulator capable of working with open/closed and air/carbon dioxide systems. This paper shows that, even though the new cycle is coupled with an atmospheric fuel cell, it is still able to achieve the same overall system efficiency and rated power than the best conventional cycles being currently considered. Furthermore, under certain operating conditions, the performance of the new hybrid systems beats that of existing pressurized fuel cell hybrid systems with conventional gas turbines. From the results, it is concluded that the supercritical carbon dioxide bottoming cycle holds a very high potential as an efficient power generator for hybrid systems. However, costs and balance of plant analysis will have to be carried out in the future to check its feasibility.

Parametric Analysis and Optimization of a High Temperature Fuel Cell: Supercritical CO2 Turbine Hybrid System

2008 ◽  
Author(s):  
D. Sa´nchez ◽  
R. Chacartegui ◽  
A. Mun˜oz ◽  
T. Sa´nchez
Keyword(s):  
Fuel Cells ◽  
High Temperature ◽  
Fuel Cell ◽  
Hybrid Systems ◽  
Hybrid System ◽  
Operating Temperature ◽  
Inlet Temperature ◽  
Brayton Cycle ◽  
Molten Carbonate ◽  
Turbine Inlet Temperature

The integration of high temperature fuel cells — molten carbonate and solid oxide — and gas turbine engines for efficient power generation is not new. Different strategies for integrating both systems have been proposed in the past ten years and there are some field tests being run presently. However, the commercial availability of such power systems seems to be continuously delayed, probably due to cost and reliability problems. The materials used in high temperature fuel cells are expensive and their cost is not decreasing at the expected pace. In fact, it looks as if they had reached stabilization. Therefore, there seems to be agreement that operating at a lower temperature might be the only way to achieve more competitive costs to enter the market, as metallic materials could then be used. From the point of view of conventional hybrid systems, decreasing the operating temperature of the cell would affect the efficiency of the bottoming cycle dramatically, as long as turbine inlet temperature is a critical parameter for the performance of a Brayton cycle. This is the reason why hybrid systems perform better with solid oxide fuel cells operating at 1000 °C than with molten carbonate cells at 650 °C typically. This work presents a hybrid system comprising a high temperature fuel cell, either SOFC or MCFC, and a bottoming Brayton cycle working with supercritical carbon dioxide. A parametric analysis is done where all the parameters affecting the performance of the hybrid system are studied, with emphasis in the bottoming cycle. For the Brayton cycle: pressure ratio, expansion and compression efficiencies, recuperator effectiveness, pressure losses, turbine inlet temperature... For the fuel cell: fuel utilization, current density, operating temperature, etc. From this analysis, optimum operating point and integration scheme are established and, after this, a comparison with conventional hybrid systems using similar fuel cells is done. Results show that, although the fuel cell is not pressurized in the CO2 based system, its performance is similar to the best conventional cycle. Furthermore, if lower operating temperatures are considered for the fuel cell, the new system performs better than any of the conventional.

Hybrid Gas Turbine and Fuel Cell Systems in Perspective Review

1999 ◽  
Author(s):  
David J. White
Keyword(s):  
Carbon Dioxide ◽  
Fuel Cells ◽  
High Temperature ◽  
Fuel Cell ◽  
Gas Turbine ◽  
Hybrid Systems ◽  
Gas Turbines ◽  
Energy Output ◽  
Net Energy ◽  
Cell Systems

The concept of hybrids combining fuel cell and gas turbine systems is without question neoteric, and probably is less than eight years old. However, this concept is in a sense a logical development derived from the many early systems that embodied the key features of rotating machinery to compress air. It was the introduction of high temperature fuel cells such as the solid oxide fuel cell (SOFC) that allowed the concept of hybrid gas turbine fuel cell systems to take root. The SOFC with an operating temperature circa 1000° C matched well with small industrial gas turbines that had firing temperatures on the same order. The recognition that the SOFC could be substituted for the gas turbine combustor was the first step into the realm of fuel cell topping systems. Fuel cells in general were recognized as having higher efficiencies at elevated pressures. Thus the hybrid topping system where the gas turbine pressurized the fuel cell and the fuel cell supplied the hot gases for expansion over the turbine promised to provide a high level of synergy between the two systems. Bottoming systems using the exhaust of a gas turbine as the working fluid of a fuel cell such as the molten carbonate fuel cell (MCFC) have been identified and are potential future power generation hybrid systems. The MCFC is especially well suited to the bottoming role because of the need to have carbon dioxide present in the inlet air stream. The carbon dioxide in the gas turbine exhaust allows the high temperature blower, normally used to recirculate and inject exhaust products into the inlet air, to be eliminated. Hybrid systems have the potential of achieving fossil fuel to electricity conversion efficiencies on the order of 70% and higher. The costs of hybrid systems in dollars per kilowatt are generally higher than say an advanced gas turbine that is available today but not by much. The net energy output over the life of a hybrid topping system is similar to that of a recuperated gas turbine but possibly lower than a high-efficiency simple-cycle machine, depending on the efficiency of the hybrid. Methodologies to aid in the selection of the hybrid system for future development have to be developed and used consistently. Life cycle analyses (LFA) provide a framework for such selection processes. In particular the concept of net energy output provides a mechanism to assign relative worth to competing concepts.

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