scholarly journals Application of a Decomposition Strategy to the Optimal Synthesis/Design of a Fuel Cell Sub-System

2002 ◽  
Author(s):  
Borja Oyarza´bal ◽  
Michael R. von Spokovsky ◽  
Michael W. Ellis ◽  
J. Ricardo Mun˜oz ◽  
Nikolaos G. Georgopoulos
Keyword(s):  
Fuel Cell ◽  
Design Optimization ◽  
Large Scale ◽  
Unit Cost ◽  
Energy System ◽  
Economic Modeling ◽  
Synthesis Design ◽  
Decomposition Strategies ◽  
Commercial Applications ◽  
Scale Optimization

The application of a decomposition methodology to the synthesis/design optimization of a stationary cogeneration fuel cell sub-system for residential/commercial applications is the focus of this paper. To accomplish this, a number of different configurations for the fuel cell sub-system were considered. The most promising candidate configuration, which combines features of different configurations found in the literature, is chosen for detailed thermodynamic, geometric, and economic modeling both at design and off-design. The case is then made for the usefulness and need of decomposition in large-scale optimization. The types of decomposition strategies considered are conceptual/time and physical decomposition. Specific solution approaches to the latter, namely Local-Global Optimization (LGO) are outlined in the paper. Conceptual/time decomposition and physical decomposition using the LGO approach are applied to the fuel cell sub-system. These techniques prove to be useful tools for simplifying the overall synthesis/design optimization problem of the fuel cell sub-system. Finally, the results of the decomposed synthesis/design optimization of the fuel cell sub-system indicate that this sub-system is more economical for a relatively large cluster of residences (i.e. 50). To achieve a unit cost of power production of less than 10 cents/kWh on an exergy basis requires the manufacture of more than 1500 fuel cell sub-system units per year. In addition, based on the off-design optimization results, the fuel cell sub-system is unable by itself to satisfy the winter heat demands. Thus, the case is made for integrating the fuel cell sub-system with another sub-system, namely, a heat pump, to form what is called a total energy system.

Optimal Synthesis/Design of a Pem Fuel Cell Cogeneration System for Multi-Unit Residential Applications–Application of a Decomposition Strategy

2004 ◽  
Vol 126 (1) ◽  
pp. 30-39 ◽  
Author(s):  
Borja Oyarza´bal ◽  
Michael R. von Spakovsky ◽  
Michael W. Ellis
Keyword(s):  
Fuel Cell ◽  
Design Optimization ◽  
Large Scale ◽  
Unit Cost ◽  
Pem Fuel Cell ◽  
Energy System ◽  
Cell System ◽  
Proton Exchange ◽  
Fuel Cell System ◽  
Synthesis Design

The application of a decomposition methodology to the synthesis/design optimization of a stationary cogeneration proton exchange membrane (PEM) fuel cell system for residential applications is the focus of this paper. Detailed thermodynamic, economic, and geometric models were developed to describe the operation and cost of the fuel processing sub-system and the fuel cell stack sub-system. Details of these models are given in an accompanying paper by the authors. In the present paper, the case is made for the usefulness and need of decomposition in large-scale optimization. The types of decomposition strategies considered are conceptual, time, and physical decomposition. Specific solution approaches to the latter, namely Local-Global Optimization (LGO) are outlined in the paper. Conceptual/time decomposition and physical decomposition using the LGO approach are applied to the fuel cell system. These techniques prove to be useful tools for simplifying the overall synthesis/design optimization problem of the fuel cell system. The results of the decomposed synthesis/design optimization indicate that this system is more economical for a relatively large cluster of residences (i.e. 50). Results also show that a unit cost of power production of less than 10 cents/kWh on an exergy basis requires the manufacture of more than 1500 fuel cell sub-system units per year. Finally, based on the off-design optimization results, the fuel cell system is unable by itself to satisfy the winter heat demands. Thus, the case is made for integrating the fuel cell system with another system, namely, a heat pump, to form what is called a total energy system.

Stochastic Modeling and Uncertainty Analysis With Multi-Objective Optimization Strategies for the Synthesis/Design and Operation/Control of a PEMFC Fuel Processing Subsystem

2008 ◽  
Author(s):  
Kihyung Kim ◽  
Meng Wang ◽  
Michael R. von Spakovsky ◽  
Douglas J. Nelson
Keyword(s):  
Uncertainty Analysis ◽  
Large Scale ◽  
Operating Cost ◽  
Energy System ◽  
Cost Models ◽  
Multi Objective Optimization ◽  
Fuel Processing ◽  
Synthesis Design ◽  
Operation Control ◽  
Processing Subsystem

A stochastic modeling and uncertainty analysis methodology for energy system synthesis/design is proposed in this paper and applied to the development of the fuel processing subsystem (FPS) of a proton exchange membrane fuel cell (PEMFC) system. The FPS consists of a steam methane reformer, both high and low temperature water-gas shift reactors, a CO preferential oxidation reactor, a steam generator, a combustor, and several heat exchangers. For each component of the system, detailed thermodynamic, geometric, chemical kinetic, and cost models are developed and integrated into an overall model for the subsystem. Conventionally, in energy system synthesis/design, such models are treated deterministically, using a specific set of non-probabilistic input variable values that produce a specific set of non-probabilistic output variable values. Even though these input values, which include the specific load profile (i.e. electrical, thermal, and/or aerodynamic) for which the system or subsystem is synthesized/designed, can have significant uncertainties that inevitably propagate through the system to the outputs, such deterministic approaches are unable to quantify these uncertainties and their effect on the final synthesis/design and operation/control. This deficiency can, of course, be overcome by treating the inputs and outputs probabilistically. The difficulty with doing this, particularly when large-scale dynamic optimization with a large number of degrees of freedom is being used to determine the optimal synthesis/design and operation/control of the system, is that the traditional probabilistic approaches (e.g., Monte Carlo Method) are so computationally intensive that combined with large-scale optimization it renders the problem computationally intractable. This difficulty can be overcome by the use of approximate approaches such as the response sensitivity analysis (RSA) method based on Taylor series expansion. In this study, RSA is employed and developed by the authors for use with dynamic energy system optimization. Load profile and cost models are treated as probabilistic input values and uncertainties in output results investigated. The results for the uncertainty analysis applied to the optimization of the FPS synthesis/design and operation/control are compared with those found using a Monte Carlo approach with good results. In this paper, the FPS synthesis/design and operation optimization is treated as a multi-objective optimization problem to minimize the capital cost and operating cost simultaneously, and uncertainty effects on the optimization are assessed by taking uncertainties into account in the objectives and constraints. Optimization results show that there is little effect on the objective (the operating cost and capital cost), while the constraints (e.g., that on the CO concentration) can be significantly affected during the synthesis/design and operation/control optimization.

Generation of Complex Energy Systems by Combination of Elementary Processes

2018 ◽  
Vol 140 (11) ◽  
Author(s):  
A. Toffolo ◽  
S. Rech ◽  
A. Lazzaretto
Keyword(s):  
Design Optimization ◽  
Ad Hoc ◽  
Energy Systems ◽  
Optimization Procedure ◽  
Thermodynamic Cycle ◽  
Energy System ◽  
Design Parameters ◽  
System Configuration ◽  
Complex Energy ◽  
Synthesis Design

The fundamental challenge in the synthesis/design optimization of energy systems is the definition of system configuration and design parameters. The traditional way to operate is to follow the previous experience, starting from the existing design solutions. A more advanced strategy consists in the preliminary identification of a superstructure that should include all the possible solutions to the synthesis/design optimization problem and in the selection of the system configuration starting from this superstructure through a design parameter optimization. This top–down approach cannot guarantee that all possible configurations could be predicted in advance and that all the configurations derived from the superstructure are feasible. To solve the general problem of the synthesis/design of complex energy systems, a new bottom–up methodology has been recently proposed by the authors, based on the original idea that the fundamental nucleus in the construction of any energy system configuration is the elementary thermodynamic cycle, composed only by the compression, heat transfer with hot and cold sources and expansion processes. So, any configuration can be built by generating, according to a rigorous set of rules, all the combinations of the elementary thermodynamic cycles operated by different working fluids that can be identified within the system, and selecting the best resulting configuration through an optimization procedure. In this paper, the main concepts and features of the methodology are deeply investigated to show, through different applications, how an artificial intelligence can generate system configurations of various complexity using preset logical rules without any “ad hoc” expertise.

Microturbine/Fuel-Cell Coupling for High-Efficiency Electrical-Power Generation

2000 ◽  
Vol 124 (1) ◽  
pp. 110-116 ◽  
Author(s):  
A. F. Massardo ◽  
C. F. McDonald ◽  
T. Korakianitis
Keyword(s):  
Fuel Cell ◽  
Power Output ◽  
Large Scale ◽  
High Efficiency ◽  
Waste Heat ◽  
Early Stage ◽  
High Reliability ◽  
Unit Cost ◽  
Hybrid Plant ◽  
Utilization Efficiency

Microturbines and fuel cells are currently attracting a lot of attention to meet future users needs in the distributed generation market. This paper addresses a preliminary analysis of a representative state-of-the-art 50-kW microturbine coupled with a high-temperature solid-oxide fuel cell (SOFC). The technologies of the two elements of such a hybrid-power plant are in a different state of readiness. The microturbine is in an early stage of pre-production and the SOFC is still in the development phase. It is premature to propose an optimum solution. Based on today’s technology the hybrid plant, using natural gas fuel, would have a power output of about 389 kW, and an efficiency of 60 percent. If the waste heat is used the overall fuel utilization efficiency would be about 80 percent. Major features, parameters, and performance of the microturbine and the SOFC are discussed. The compatibility of the two systems is addressed, and the areas of technical concern, and mismatching issues are identified and discussed. Fully understanding these, and identifying solutions, is the key to the future establishing of an optimum overall system. This approach is viewed as being in concert with evolving technological changes. In the case of the microturbine changes will be fairly minor as they enter production on a large scale within the next year or so, but are likely to be significant for the SOFC in the next few years, as extensive efforts are expended to reduce unit cost. It is reasonable to project that a high performance and cost-effective hybrid plant, with high reliability, will be ready for commercial service in the middle of the first decade of the 21st century. While several microturbines can be packaged to give an increased level of power, this can perhaps be more effectively accomplished by coupling just a single gas turbine module with a SOFC. The resultant larger power output unit opens up new market possibilities in both the industrial nations and developing countries.

Fuel Cell Integrated Energy System for Residential and Commercial Applications

2005 ◽  
Author(s):  
William E. Simon ◽  
Terrence L. Chambers ◽  
John L. Guillory ◽  
Varaprasad Ventrapragada ◽  
Jeremy R. Angelle ◽  
...  
Keyword(s):  
Fuel Cell ◽  
High Performance ◽  
Gulf Coast ◽  
Energy Systems ◽  
Cost Effective ◽  
Energy System ◽  
Humid Climate ◽  
Integrated Energy System ◽  
University Of Louisiana ◽  
Commercial Applications

Until recently the cost of fuel cells for terrestrial applications was prohibitive. Recently, several companies have begun developing high-performance, long-life and cost-effective fuel cell systems, and commercial units are now becoming available for stationary power generation. These systems can often be operated in conjunction with other energy systems to increase overall operational efficiency. A recent technology demonstration project at the University of Louisiana at Lafayette involved the installation, operation and analysis of a fuel cell and a desiccant dehumidification system, which is considered a good combination for the hot, humid climate of the U.S. Gulf coast. The three-year project involved technology assessment, hardware selection and procurement, installation, and operation of the two systems, followed by a performance analysis. The results were reported in a regional symposium. This paper describes the project, focusing on system operation and the results obtained, and predicts future possibilities for integrated energy systems of this type.

Microturbine / Fuel-Cell Coupling for High-Efficiency Electrical-Power Generation

2000 ◽  
Author(s):  
Aristide F. Massardo ◽  
Colin F. McDonald ◽  
Theodosios Korakianitis
Keyword(s):  
Fuel Cell ◽  
Power Output ◽  
Large Scale ◽  
High Efficiency ◽  
Waste Heat ◽  
Early Stage ◽  
High Reliability ◽  
Unit Cost ◽  
Hybrid Plant ◽  
Utilization Efficiency

Microturbines and fuel cells are currently attracting a lot of attention to meet future users needs in the distributed generation market. This paper addresses a preliminary analysis of a representative state-of-the-art 50 kW microturbine coupled with a high-temperature solid-oxide fuel cell (SOFC). The technologies of the two elements of such a hybrid-power plant are in a different state of readiness. The microturbine is in an early stage of pre-production and the SOFC is still in the development phase. It is premature to propose an optimum solution. Based on today’s technology the hybrid plant, using natural gas fuel, would have a power output of about 389 kW, and an efficiency of 60 percent. If the waste heat is used the overall fuel utilization efficiency would about 80 percent. Major features, parameters and performance of the microturbine and the SOFC are discussed. The compatibility of the two systems is addressed, and the areas of technical concern, and mismatching issues are identified and discussed. Fully understanding these, and identifying solutions, is the key to the future establishing of an optimum overall system. This approach is viewed as being in concert with evolving technological changes. In the case of the microturbine changes will be fairly minor as they enter production on a large scale within the next year or so, but are likely to be significant for the SOFC in the next few years, as extensive efforts are expended to reduce unit cost. It is reasonable to project that a high performance and cost-effective hybrid plant, with high reliability, will be ready for commercial service in the middle of the first decade of the 21st century. While several microturbines can be packaged to give an increased level of power, this can perhaps be more effectively accomplished by coupling just a single gas turbine module with a SOFC. The resultant larger power output unit opens up new market possibilities in both the industrial nations and developing countries.

Design and Modeling of an Integrated CHP System With Solar Hydrogen/Methane Fueled PEM Fuel Cell for Residential Applications

2014 ◽  
Author(s):  
Hajar Amirian ◽  
Farid Sayedin ◽  
Azadeh Maroufmashat
Keyword(s):  
Fuel Cell ◽  
Solar Energy ◽  
Alternative Energy ◽  
Unit Cost ◽  
Cost Benefit ◽  
Electrical Energy ◽  
Energy System ◽  
Hot Water ◽  
Total Annual Cost ◽  
Cell Efficiency

This paper describes the designing and evaluation of an alternative energy system which consists of PEMFC, PV, PEM electrolyser, methane reformer and hydrogen tank. In order to find out the minimum capacity of the components, a system sizing model is developed in MATLAB based on meteorological and electrical demand data. Three scenarios are considered based on different combinations of solar energy and fossil fuel energy as energy resources. The heating energy produced by the fuel cell is recovered for supplying domestic hot water while the system would supply electrical energy. Results show that system sizing strongly depends on scenarios and unit cost of electricity decreases through the reduction of solar energy contribution in scenarios. CHP analysis indicates that the overall energy efficiency and fuel cell efficiency are increased approximately 3.4% and 40% respectively. Furthermore, the cost benefit ratio of using the fuel cell heat is equivalent to 25% of the total annual cost of the electricity.

A Decomposition Strategy Based on Thermoeconomic Isolation Applied to the Optimal Synthesis/Design and Operation of a Fuel Cell Based Total Energy System

2002 ◽  
Author(s):  
Nikolaos G. Georgopoulos ◽  
Michael R. von Spakovsky ◽  
J. Ricardo Mun˜oz
Keyword(s):  
Fuel Cell ◽  
Total Energy ◽  
Proton Exchange Membrane ◽  
Energy System ◽  
Proton Exchange ◽  
Major Advance ◽  
Energy Integration ◽  
Synthesis Design ◽  
Operational Optimization ◽  
Local Decision

A decomposition methodology based on the concept of “thermoeconomic isolation” applied to the synthesis/design and operational optimization of a stationary cogeneration proton exchange membrane fuel cell (PEMFC) based total energy system (TES) for residential/commercial applications is the focus of this paper. A number of different configurations for the FC based TES were considered. The most promising set based on an energy integration analysis of candidate configurations was developed and detailed thermodynamic, kinetic, geometric, and economic models at both design and off-design were formulated and implemented. An original decomposition strategy called Iterative Local-Global Optimization (ILGO) developed in earlier work by two of the authors was then applied to the synthesis/design and operational optimization of the FC based TES. This decomposition strategy is the first to successfully closely approach the theoretical condition of “thermoeconomic isolation” when applied to highly complex, nonlinear systems. This contrasts with past attempts to approach this condition, all of which were applied to very simple systems under very special and restricted conditions such as those requiring linearity in the models and strictly local decision variables. This is a major advance in decomposition and has now been successfully applied to a number of highly complex, highly non-linear, and dynamic transportation and stationary systems. This paper presents the detailed results from one such application.

Balancing a High-Renewables Electric Grid With Hydrogen-Fuelled Combined Cycles: A Country Scale Analysis

2020 ◽  
Author(s):  
Paolo Colbertaldo ◽  
Giulio Guandalini ◽  
Elena Crespi ◽  
Stefano Campanari
Keyword(s):  
Power Generation ◽  
Energy Storage ◽  
Fuel Cell ◽  
Natural Gas ◽  
Large Scale ◽  
Clean Energy ◽  
Energy System ◽  
Electric Grid ◽  
Combined Cycles

Abstract A key approach to large renewable energy sources (RES) power management is based on implementing storage technologies, including batteries, power-to-hydrogen (P2H), pumped-hydro, and compressed air energy storage. Power-to-hydrogen presents specific advantages in terms of suitability for large-scale and long-term energy storage as well as capability to decarbonize a wide range of end-use sectors, e.g., including both power generation and mobility. This work applies a multi-nodal model for the hourly simulation of the energy system at a nation scale, integrating the power, transport, and natural gas sectors. Three main infrastructures are considered: (i) the power grid, characterized by instantaneous supply-demand balance and featuring a variety of storage options; (ii) the natural gas network, which can host a variable hydrogen content, supplying NG-H2 blends to the final consumers; (iii) the hydrogen production, storage, and re-electrification facilities. The aim of the work is to assess the role that can be played by gas turbine-based combined cycles in the future high-RES electric grid. Combined cycles (GTCCs) would exploit hydrogen generated by P2H implementation at large scale, transported through the natural gas infrastructure at increasingly admixed fractions, thus closing the power-to-power (P2P) conversion of excess renewables and becoming a strategic asset for future grid balancing applications. A long-term scenario of the Italian energy system is analyzed, involving a massive increase of intermittent RES power generation capacity and a significant introduction of low-emission vehicles based on electric drivetrains (pure-battery or fuel-cell). The analysis highlights the role of hydrogen as clean energy vector, not only for specific use in new applications like fuel cell vehicles and stationary fuel cells, but also for substitution of fossil fuels in conventional combustion devices. The study also explores the option of repowering the combined cycles at current sites and evaluates the effect of inter-zonal limits on power and hydrogen exchange. Moreover, results include the evaluation of the required hydrogen storage size, distributed at regional scale or in correspondence of the power plant sites. Results show that when extra hydrogen generated by P2H is fed to GTCCs, up to 17–24% H2 use is achieved, reaching up to 70–100% in southern regions, with a parallel reduction in fossil NG input and CO2 emissions of the GTCC plants.

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