Documents disponibles écrits par cet auteur

Linear quadratic regulator for a bottoming solid oxide fuel cell gas turbine hybrid system / Fabian Mueller in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 131 N° 5 (Septembre 2009) 

Public ISBD [article]  in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 131 N° 5 (Septembre 2009) . - 09 p. Titre : Linear quadratic regulator for a bottoming solid oxide fuel cell gas turbine hybrid system Type de document : texte imprimé Auteurs : Fabian Mueller, Auteur ; Jabbari, Faryar, Auteur ; Jacob Brouwer, Auteur Année de publication : 2009 Article en page(s) : 09 p. Note générale : dynamic systems Langues : Anglais (eng) Mots-clés : fuel  cell  gas  turbine  hybrid;  subsystems;  control  algorithms Résumé : The control system for fuel cell gas turbine hybrid power plants plays an important role in achieving synergistic operation of subsystems, improving reliability of operation, and reducing frequency of maintenance and downtime. In this paper, we discuss development of advanced control algorithms for a system composed of an internally reforming solid oxide fuel cell coupled with an indirectly heated Brayton cycle gas turbine. In high temperature fuel cells it is critical to closely maintain fuel cell temperatures and to provide sufficient electrochemical reacting species to ensure system durability. The control objective explored here is focused on maintaining the system power output, temperature constraints, and target fuel utilization, in the presence of ambient temperature and fuel composition perturbations. The present work details the development of a centralized linear quadratic regulator (LQR) including state estimation via Kalman filtering. The controller is augmented by local turbine speed control and integral system power control. Relative gain array analysis has indicated that independent control loops of the hybrid system are coupled at time scales greater than 1 s. The objective of the paper is to quantify the performance of a centralized LQR in rejecting fuel and ambient temperature disturbances compared with a previously developed decentralized controller. Results indicate that both the LQR and decentralized controller can well maintain the system power to the disturbances. However, the LQR ensures better maintenance of the fuel cell stack voltage and temperature that can improve high temperature fuel cell system durability. DEWEY : 629.8 ISSN : 0022-0434 En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...] [article] Linear quadratic regulator for a bottoming solid oxide fuel cell gas turbine hybrid system [texte imprimé] / Fabian Mueller, Auteur ; Jabbari, Faryar, Auteur ; Jacob Brouwer, Auteur . - 2009 . - 09 p. dynamic systems Langues : Anglais (eng) in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 131 N° 5 (Septembre 2009) . - 09 p. Mots-clés : fuel  cell  gas  turbine  hybrid;  subsystems;  control  algorithms Résumé : The control system for fuel cell gas turbine hybrid power plants plays an important role in achieving synergistic operation of subsystems, improving reliability of operation, and reducing frequency of maintenance and downtime. In this paper, we discuss development of advanced control algorithms for a system composed of an internally reforming solid oxide fuel cell coupled with an indirectly heated Brayton cycle gas turbine. In high temperature fuel cells it is critical to closely maintain fuel cell temperatures and to provide sufficient electrochemical reacting species to ensure system durability. The control objective explored here is focused on maintaining the system power output, temperature constraints, and target fuel utilization, in the presence of ambient temperature and fuel composition perturbations. The present work details the development of a centralized linear quadratic regulator (LQR) including state estimation via Kalman filtering. The controller is augmented by local turbine speed control and integral system power control. Relative gain array analysis has indicated that independent control loops of the hybrid system are coupled at time scales greater than 1 s. The objective of the paper is to quantify the performance of a centralized LQR in rejecting fuel and ambient temperature disturbances compared with a previously developed decentralized controller. Results indicate that both the LQR and decentralized controller can well maintain the system power to the disturbances. However, the LQR ensures better maintenance of the fuel cell stack voltage and temperature that can improve high temperature fuel cell system durability. DEWEY : 629.8 ISSN : 0022-0434 En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...]

Parametric thermodynamic analysis of a solid oxide fuel cell gas turbine system design space / Brian Tarroja in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 7 (Juillet 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 7 (Juillet 2010) . - 11 p. Titre : Parametric thermodynamic analysis of a solid oxide fuel cell gas turbine system design space Type de document : texte imprimé Auteurs : Brian Tarroja, Auteur ; Fabian Mueller, Auteur ; Jim Maclay, Auteur Année de publication : 2011 Article en page(s) : 11 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Current  density  Fuel  cell  power  plants  Gas  turbines  Heat  exchangers  Solid  oxide  fuel  cells  Thermodynamics Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : A parametric study of a solid oxide fuel cell-gas turbine (SOFC-GT) hybrid system design is conducted with the intention of determining the thermodynamically based design space constrained by modern material and operating limits. The analysis is performed using a thermodynamic model of a generalized SOFC-GT system where the sizing of all components, except the fuel cell, is allowed to vary. Effects of parameters such as pressure ratio, fuel utilization, oxygen utilization, and current density are examined. Operational limits are discussed in terms of maximum combustor exit temperature, maximum heat exchanger effectiveness, limiting current density, maximum hydrogen utilization, and fuel cell temperature rise. It was found that the maximum hydrogen utilization and combustor exit temperature were the most significant constraints on the system design space. The design space includes the use of cathode flow recycling and air preheating via a recuperator (heat exchanger). The effect on system efficiency of exhaust gas recirculation using an ejector versus using a blower is discussed, while both are compared with the base case of using a heat exchanger only. It was found that use of an ejector for exhaust gas recirculation caused the highest efficiency loss, and the base case was found to exhibit the highest overall system efficiency. The use of a cathode recycle blower allowed the largest downsizing of the heat exchanger, although avoiding cathode recycling altogether achieved the highest efficiency. Efficiencies in the range of 50–75% were found for variations in pressure ratio, fuel utilization, oxygen utilization, and current density. The best performing systems that fell within all design constraints were those that used a heat exchanger only to preheat air, moderate pressure ratios, low oxygen utilizations, and high fuel utilizations. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] Parametric thermodynamic analysis of a solid oxide fuel cell gas turbine system design space [texte imprimé] / Brian Tarroja, Auteur ; Fabian Mueller, Auteur ; Jim Maclay, Auteur . - 2011 . - 11 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 7 (Juillet 2010) . - 11 p. Mots-clés : Current  density  Fuel  cell  power  plants  Gas  turbines  Heat  exchangers  Solid  oxide  fuel  cells  Thermodynamics Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : A parametric study of a solid oxide fuel cell-gas turbine (SOFC-GT) hybrid system design is conducted with the intention of determining the thermodynamically based design space constrained by modern material and operating limits. The analysis is performed using a thermodynamic model of a generalized SOFC-GT system where the sizing of all components, except the fuel cell, is allowed to vary. Effects of parameters such as pressure ratio, fuel utilization, oxygen utilization, and current density are examined. Operational limits are discussed in terms of maximum combustor exit temperature, maximum heat exchanger effectiveness, limiting current density, maximum hydrogen utilization, and fuel cell temperature rise. It was found that the maximum hydrogen utilization and combustor exit temperature were the most significant constraints on the system design space. The design space includes the use of cathode flow recycling and air preheating via a recuperator (heat exchanger). The effect on system efficiency of exhaust gas recirculation using an ejector versus using a blower is discussed, while both are compared with the base case of using a heat exchanger only. It was found that use of an ejector for exhaust gas recirculation caused the highest efficiency loss, and the base case was found to exhibit the highest overall system efficiency. The use of a cathode recycle blower allowed the largest downsizing of the heat exchanger, although avoiding cathode recycling altogether achieved the highest efficiency. Efficiencies in the range of 50–75% were found for variations in pressure ratio, fuel utilization, oxygen utilization, and current density. The best performing systems that fell within all design constraints were those that used a heat exchanger only to preheat air, moderate pressure ratios, low oxygen utilizations, and high fuel utilizations. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]