This paper presents a novel startup approach for solid oxide fuel cell (SOFC) hybrid systems (HSs) based on recompression technology. This startup approach shows a novel method of managing a complete plant to obtain better performance, which is always also a difficult task for equipment manufactures. The research activities were carried out using the HS emulator rig located in Savona (Italy) and developed by the Thermochemical Power Group (TPG) of the University of Genoa. The test rig consists of three integrated technologies: a 100 kWe recuperated microturbine modified for external connections, a high temperature modular vessel necessary to emulate the dimensions of an SOFC stack, and, for air recompression, a turbocharger necessary to increase fuel cell pressure (using part of the recuperator outlet flow) as required for efficiency increase and to manage the cathodic recirculation. It was necessary to develop a theoretical model in order to prevent abnormal plant startup conditions as well as motivated by economic considerations. This transient model of the emulator rig was developed using Matlab®-Simulink® environment to study the time-dependent (including the control system aspects) behavior during the entire system (emulator equipped with the turbocharger) startup condition. The results obtained were able to demonstrate that the HS startup phase can be safely managed with better performance developing a new control logic. In detail, the startup phase reported in this paper shows that all important parameters were always inside acceptable operating zones (surge margin kept above 1.1, turbine outlet temperature (TOT), and fuel flow maintained lower than 918.15 K and 7.7 g/s, respectively).
{"title":"Simulation of an Innovative Startup Phase for SOFC Hybrid Systems Based on Recompression Technology: Emulator Test Rig","authors":"U. Damo, M. L. Ferrari, A. Turan, A. Massardo","doi":"10.1115/1.4031106","DOIUrl":"https://doi.org/10.1115/1.4031106","url":null,"abstract":"This paper presents a novel startup approach for solid oxide fuel cell (SOFC) hybrid systems (HSs) based on recompression technology. This startup approach shows a novel method of managing a complete plant to obtain better performance, which is always also a difficult task for equipment manufactures. The research activities were carried out using the HS emulator rig located in Savona (Italy) and developed by the Thermochemical Power Group (TPG) of the University of Genoa. The test rig consists of three integrated technologies: a 100 kWe recuperated microturbine modified for external connections, a high temperature modular vessel necessary to emulate the dimensions of an SOFC stack, and, for air recompression, a turbocharger necessary to increase fuel cell pressure (using part of the recuperator outlet flow) as required for efficiency increase and to manage the cathodic recirculation. It was necessary to develop a theoretical model in order to prevent abnormal plant startup conditions as well as motivated by economic considerations. This transient model of the emulator rig was developed using Matlab®-Simulink® environment to study the time-dependent (including the control system aspects) behavior during the entire system (emulator equipped with the turbocharger) startup condition. The results obtained were able to demonstrate that the HS startup phase can be safely managed with better performance developing a new control logic. In detail, the startup phase reported in this paper shows that all important parameters were always inside acceptable operating zones (surge margin kept above 1.1, turbine outlet temperature (TOT), and fuel flow maintained lower than 918.15 K and 7.7 g/s, respectively).","PeriodicalId":15829,"journal":{"name":"Journal of Fuel Cell Science and Technology","volume":"1 1","pages":"041004"},"PeriodicalIF":0.0,"publicationDate":"2015-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1115/1.4031106","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63491083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Triple-Layer Control System for Molten Carbonate Fuel Cell–Gas Turbine Hybrid System","authors":"J. Milewski, P. Biczel, M. Kłos","doi":"10.1115/1.4031169","DOIUrl":"https://doi.org/10.1115/1.4031169","url":null,"abstract":"","PeriodicalId":15829,"journal":{"name":"Journal of Fuel Cell Science and Technology","volume":"12 1","pages":"041005"},"PeriodicalIF":0.0,"publicationDate":"2015-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1115/1.4031169","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63491051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The Effect of Nonuniform Under-Rib Convection on Reactant and Liquid Water Distribution in Proton Exchange Membrane Fuel Cells","authors":"P. Jithesh, T. Sundararajan, Sarit K. Das","doi":"10.1115/1.4030514","DOIUrl":"https://doi.org/10.1115/1.4030514","url":null,"abstract":"","PeriodicalId":15829,"journal":{"name":"Journal of Fuel Cell Science and Technology","volume":"12 1","pages":"041003"},"PeriodicalIF":0.0,"publicationDate":"2015-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1115/1.4030514","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63490381","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Mukai, T. Fujita, S. Tsukui, KEN-ICHI Yoshida, M. Adachi, K. Goretta
Yttria-stabilized zirconia (YSZ) thin films were deposited by pulsed laser deposition (PLD) at laser repetition frequencies of 10–50 Hz. Controlling the laser repetition frequency can achieve high deposition rate of YSZ, but high deposition rate at high laser repetition frequency can adversely affect the crystallinity of the resulting film. In the present work, X-ray diffraction (XRD) of YSZ thin films deposited at 10–50 Hz unexpectedly indicated no significant differences. Well-crystallized YSZ thin films were obtained for all laser repetition frequencies. This result may be due to a sufficient substrate temperature of 1000 K during processing. The oxide-ion conductivity of each thin film was comparable to that of bulk YSZ. Only minor differences in Y2O3 content, residual stress, grain size, and grain-boundary width were observed among the films. We concluded that similar quality YSZ thin films were obtained at all deposition frequencies. Oxide-ion conductivity was affected by the temperature at which the substrate was deposited. The YSZ thin films deposited at 900 K and 1000 K showed similar oxide-ion conductivity and films deposited at 800 K showed lower oxide-ion conductivity. This difference could perhaps be due to narrow grain-boundary width. The YSZ thin film with highest oxide-ion conductivity was fabricated at an intermediate substrate temperature of 900 K with a deposition rate of 86 nm·min−1 at 50 Hz, without additional high-temperature annealing greater than 1273 K. The YSZ growth rates were faster than the rates for other gas-phase methods such as midfrequency and DC sputtering.
{"title":"Effect of Rate on Pulsed Laser Deposition of Yttria-Stabilized Zirconia Electrolyte Thin Films for SOFCs","authors":"T. Mukai, T. Fujita, S. Tsukui, KEN-ICHI Yoshida, M. Adachi, K. Goretta","doi":"10.1115/1.4029423","DOIUrl":"https://doi.org/10.1115/1.4029423","url":null,"abstract":"Yttria-stabilized zirconia (YSZ) thin films were deposited by pulsed laser deposition (PLD) at laser repetition frequencies of 10–50 Hz. Controlling the laser repetition frequency can achieve high deposition rate of YSZ, but high deposition rate at high laser repetition frequency can adversely affect the crystallinity of the resulting film. In the present work, X-ray diffraction (XRD) of YSZ thin films deposited at 10–50 Hz unexpectedly indicated no significant differences. Well-crystallized YSZ thin films were obtained for all laser repetition frequencies. This result may be due to a sufficient substrate temperature of 1000 K during processing. The oxide-ion conductivity of each thin film was comparable to that of bulk YSZ. Only minor differences in Y2O3 content, residual stress, grain size, and grain-boundary width were observed among the films. We concluded that similar quality YSZ thin films were obtained at all deposition frequencies. Oxide-ion conductivity was affected by the temperature at which the substrate was deposited. The YSZ thin films deposited at 900 K and 1000 K showed similar oxide-ion conductivity and films deposited at 800 K showed lower oxide-ion conductivity. This difference could perhaps be due to narrow grain-boundary width. The YSZ thin film with highest oxide-ion conductivity was fabricated at an intermediate substrate temperature of 900 K with a deposition rate of 86 nm·min−1 at 50 Hz, without additional high-temperature annealing greater than 1273 K. The YSZ growth rates were faster than the rates for other gas-phase methods such as midfrequency and DC sputtering.","PeriodicalId":15829,"journal":{"name":"Journal of Fuel Cell Science and Technology","volume":"12 1","pages":"031002"},"PeriodicalIF":0.0,"publicationDate":"2015-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1115/1.4029423","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63488321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A numerical model has been developed for the performance analysis of solid oxide fuel cell (SOFC)/micro gas turbine (MGT) hybrid systems with prereforming of natural gas, in which a quasi two-dimensional model has been built up to simulate the cell electrochemical reaction, heat and mass transfer within tubular SOFC. The developed model can be used not only to predict the overall performance of the SOFC/MGT hybrid system but also to reveal the nonuniform temperature distribution within SOFC unit. The effects of turbine inlet temperature (TIT) and pressure ratio (PR) on the performance of the hybrid system have been investigated. The results show that selecting smaller TIT or PR value will lead to relative higher system efficiency and lower CO2 emission ratio; however, this will raise the risk to destroy SOFC beyond the limitation temperature of electrolyte.
{"title":"Conceptual Design and Performance Analysis of SOFC/Micro Gas Turbine Hybrid Distributed Energy System","authors":"Zheng Dang, Hua Zhao, G. Xi","doi":"10.1115/1.4029395","DOIUrl":"https://doi.org/10.1115/1.4029395","url":null,"abstract":"A numerical model has been developed for the performance analysis of solid oxide fuel cell (SOFC)/micro gas turbine (MGT) hybrid systems with prereforming of natural gas, in which a quasi two-dimensional model has been built up to simulate the cell electrochemical reaction, heat and mass transfer within tubular SOFC. The developed model can be used not only to predict the overall performance of the SOFC/MGT hybrid system but also to reveal the nonuniform temperature distribution within SOFC unit. The effects of turbine inlet temperature (TIT) and pressure ratio (PR) on the performance of the hybrid system have been investigated. The results show that selecting smaller TIT or PR value will lead to relative higher system efficiency and lower CO2 emission ratio; however, this will raise the risk to destroy SOFC beyond the limitation temperature of electrolyte.","PeriodicalId":15829,"journal":{"name":"Journal of Fuel Cell Science and Technology","volume":"12 1","pages":"031003"},"PeriodicalIF":0.0,"publicationDate":"2015-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1115/1.4029395","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63488522","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Microtubular anode-supported solid oxide fuel cells (lt-SOFC) were created with ametallic coil embedded in the anode to act as current collector. The electrochemical per-formance was experimentally examined by comparing the power density (PD) oflt-SOFC with embedded coils of different turns per unit length and composition (nickeland palladium). It is shown that an increase in the turns per unit length results in a pro-portional current density increase and in a quadratic increment of PD. Additional per-formance improvement is found for the cell with palladium current collector due to thehigher catalytic activity for hydrogen oxidation. [DOI: 10.1115/1.4029875]Keywords: current collector, anode-supported SOFC, microtubular SOFC, electrochemicalperformance
{"title":"Effect of the Current Collector on Performance of Anode-Supported Microtubular Solid Oxide Fuel Cells","authors":"M. Casarin, V. Sglavo","doi":"10.1115/1.4029875","DOIUrl":"https://doi.org/10.1115/1.4029875","url":null,"abstract":"Microtubular anode-supported solid oxide fuel cells (lt-SOFC) were created with ametallic coil embedded in the anode to act as current collector. The electrochemical per-formance was experimentally examined by comparing the power density (PD) oflt-SOFC with embedded coils of different turns per unit length and composition (nickeland palladium). It is shown that an increase in the turns per unit length results in a pro-portional current density increase and in a quadratic increment of PD. Additional per-formance improvement is found for the cell with palladium current collector due to thehigher catalytic activity for hydrogen oxidation. [DOI: 10.1115/1.4029875]Keywords: current collector, anode-supported SOFC, microtubular SOFC, electrochemicalperformance","PeriodicalId":15829,"journal":{"name":"Journal of Fuel Cell Science and Technology","volume":"12 1","pages":"031005"},"PeriodicalIF":0.0,"publicationDate":"2015-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1115/1.4029875","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63489231","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pacific Northwest National Laboratory (PNNL) is working with industry to independently monitor up to 15 distinct 5 kW-electric (kWe) combined heat and power (CHP) high temperature (HT) proton exchange membrane (PEM) fuel cell systems (FCSs) installed in light commercial buildings. This research paper discusses an evaluation of the first six months of measured performance data acquired at a 1 s sampling rate from real-time monitoring equipment attached to the FCSs at building sites. Engineering performance parameters are independently evaluated. Based on an analysis of the first few months of measured operating data, FCS performance is consistent with manufacturer-stated performance. Initial data indicate that the FCSs have relatively stable performance and a long-term average production of about 4.57 kWe of power. This value is consistent with, but slightly below, the manufacturer's stated rated electric power output of 5 kWe. The measured system net electric efficiency has averaged 33.7%, based on the higher heating value (HHV) of natural gas fuel. This value, also, is consistent with, but slightly below, the manufacturer's stated rated electric efficiency of 36%. The FCSs provide low-grade hot water to the building at a measured average temperature of about 48.4 °C, lower than the manufacturer's stated maximum hot water delivery temperature of 65 °C. The uptime of the systems is also evaluated. System availability can be defined as the quotient of total operating time compared to time since commissioning. The average values for system availability vary between 96.1 and 97.3%, depending on the FCS evaluated in the field. Performance at rated value for electrical efficiency (PRVeff) can be defined as the quotient of the system time operating at or above the rated electric efficiency and the time since commissioning. The PRVeff varies between 5.6% and 31.6%, depending on the FCS field unit evaluated. Performance at rated value for electrical power (PRVp) can be defined as the quotient of the system time operating at or above the rated electric power and the time since commissioning. PRVp varies between 6.5% and 16.2%. Performance at rated value for electrical efficiency and power (PRVt) can be defined as the quotient of the system time operating at or above both the rated electric efficiency and the electric power output compared to the time since commissioning. PRVt varies between 0.2% and 1.4%. Optimization to determine the manufacturer rating required to achieve PRVt greater than 80% has been performed based on the collected data. For example, for FCS Unit 130 to achieve a PRVt of 95%, it would have to be down-rated to an electrical power output of 3.2 kWe and an electrical efficiency of 29%. The use of PRV as an assessment metric for FCSs has been developed and reported for the first time in this paper. For FCS Unit 130, a maximum decline in electric power output of approximately 18% was observed over a 500 h period in Jan. 2012.
太平洋西北国家实验室(PNNL)正在与工业界合作，独立监测安装在轻型商业建筑中的多达15个不同的5千瓦电(kWe)热电联产(CHP)高温(HT)质子交换膜(PEM)燃料电池系统(FCSs)。本研究论文讨论了前六个月的测量性能数据的评估，这些数据以1秒的采样率从建筑工地的fcs附带的实时监测设备中获得。工程性能参数独立评估。根据对前几个月测量运行数据的分析，FCS的性能与制造商声明的性能一致。初步数据表明，fcs具有相对稳定的性能，长期平均发电量约为4.57千瓦时。该值与制造商规定的5千瓦时的额定输出功率一致，但略低于此值。基于天然气燃料较高的热值(HHV)，实测系统净电效率平均为33.7%。这个值，也，是一致的，但略低于制造商所声明的额定电效率36%。FCSs为建筑提供低品位热水，平均测量温度约为48.4℃，低于制造商规定的最高热水输送温度65℃。还评估了系统的正常运行时间。系统可用性可以定义为总运行时间与自调试以来的时间之比。系统可用性的平均值在96.1和97.3%之间变化，这取决于在现场评估的FCS。额定电效率(PRVeff)下的性能可以定义为系统在额定电效率或高于额定电效率下运行的时间与调试以来的时间之商。根据评估的FCS现场单元，PRVeff在5.6%至31.6%之间变化。额定功率下的性能(PRVp)可以定义为系统在额定功率或高于额定功率下运行的时间与调试以来的时间之商。PRVp在6.5%到16.2%之间。电效率和功率额定值下的性能(PRVt)可以定义为系统在额定电效率和输出电功率下或高于额定电效率的运行时间与调试以来的时间之商。PRVt在0.2%到1.4%之间变化。根据收集的数据进行了优化，以确定实现PRVt大于80%所需的制造商评级。例如，为了使FCS Unit 130达到95%的PRVt，它必须将额定功率降低到3.2 kWe，电气效率为29%。本文首次提出并报道了利用PRV作为fcs评估指标的方法。2012年1月，FCS 130机组在500小时的时间内，电力输出最大降幅约为18%。
{"title":"Independent Analysis of Real-Time, Measured Performance Data From Microcogenerative Fuel Cell Systems Installed in Buildings","authors":"H. Dillon, W. Colella","doi":"10.1115/1.4007162","DOIUrl":"https://doi.org/10.1115/1.4007162","url":null,"abstract":"Pacific Northwest National Laboratory (PNNL) is working with industry to independently monitor up to 15 distinct 5 kW-electric (kWe) combined heat and power (CHP) high temperature (HT) proton exchange membrane (PEM) fuel cell systems (FCSs) installed in light commercial buildings. This research paper discusses an evaluation of the first six months of measured performance data acquired at a 1 s sampling rate from real-time monitoring equipment attached to the FCSs at building sites. Engineering performance parameters are independently evaluated. Based on an analysis of the first few months of measured operating data, FCS performance is consistent with manufacturer-stated performance. Initial data indicate that the FCSs have relatively stable performance and a long-term average production of about 4.57 kWe of power. This value is consistent with, but slightly below, the manufacturer's stated rated electric power output of 5 kWe. The measured system net electric efficiency has averaged 33.7%, based on the higher heating value (HHV) of natural gas fuel. This value, also, is consistent with, but slightly below, the manufacturer's stated rated electric efficiency of 36%. The FCSs provide low-grade hot water to the building at a measured average temperature of about 48.4 °C, lower than the manufacturer's stated maximum hot water delivery temperature of 65 °C. The uptime of the systems is also evaluated. System availability can be defined as the quotient of total operating time compared to time since commissioning. The average values for system availability vary between 96.1 and 97.3%, depending on the FCS evaluated in the field. Performance at rated value for electrical efficiency (PRVeff) can be defined as the quotient of the system time operating at or above the rated electric efficiency and the time since commissioning. The PRVeff varies between 5.6% and 31.6%, depending on the FCS field unit evaluated. Performance at rated value for electrical power (PRVp) can be defined as the quotient of the system time operating at or above the rated electric power and the time since commissioning. PRVp varies between 6.5% and 16.2%. Performance at rated value for electrical efficiency and power (PRVt) can be defined as the quotient of the system time operating at or above both the rated electric efficiency and the electric power output compared to the time since commissioning. PRVt varies between 0.2% and 1.4%. Optimization to determine the manufacturer rating required to achieve PRVt greater than 80% has been performed based on the collected data. For example, for FCS Unit 130 to achieve a PRVt of 95%, it would have to be down-rated to an electrical power output of 3.2 kWe and an electrical efficiency of 29%. The use of PRV as an assessment metric for FCSs has been developed and reported for the first time in this paper. For FCS Unit 130, a maximum decline in electric power output of approximately 18% was observed over a 500 h period in Jan. 2012.","PeriodicalId":15829,"journal":{"name":"Journal of Fuel Cell Science and Technology","volume":"12 1","pages":"031007"},"PeriodicalIF":0.0,"publicationDate":"2015-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1115/1.4007162","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63474703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Due to the tight coupling of physical processes inside solid oxide fuel cells (SOFCs), efficient control of these devices depends largely on the proper pairing of controlled and manipulated variables. The present study investigates the uncontrolled, dynamic behavior of an SOFC stack that is intended for use in a hybrid SOFC-gas turbine (GT) system. A numerical fuel cell model is developed based on charge, species mass, energy, and momentum balances, and an equivalent circuit is used to combine the fuel cell's irreversibilities. The model is then verified on electrochemical, mass, and thermal timescales. The open-loop response of the average positive electrode-electrolyte-negative electrode (PEN) temperature, fuel utilization, and SOFC power to step changes in the inlet fuel flow rate, current density, and inlet air flow rate is simulated on different timescales. Results indicate that manipulating the current density is the quickest and most efficient way to change the SOFC power. Meanwhile, manipulating the fuel flow is found to be the most efficient way to change the fuel utilization. In future work, it is recommended that such control strategies be further analyzed and compared in the context of a complete SOFC-GT system model.
{"title":"SOFC Stack Model for Integration Into a Hybrid System: Stack Response to Control Variables","authors":"Michael M. Whiston, M. Bilec, L. Schaefer","doi":"10.1115/1.4029877","DOIUrl":"https://doi.org/10.1115/1.4029877","url":null,"abstract":"Due to the tight coupling of physical processes inside solid oxide fuel cells (SOFCs), efficient control of these devices depends largely on the proper pairing of controlled and manipulated variables. The present study investigates the uncontrolled, dynamic behavior of an SOFC stack that is intended for use in a hybrid SOFC-gas turbine (GT) system. A numerical fuel cell model is developed based on charge, species mass, energy, and momentum balances, and an equivalent circuit is used to combine the fuel cell's irreversibilities. The model is then verified on electrochemical, mass, and thermal timescales. The open-loop response of the average positive electrode-electrolyte-negative electrode (PEN) temperature, fuel utilization, and SOFC power to step changes in the inlet fuel flow rate, current density, and inlet air flow rate is simulated on different timescales. Results indicate that manipulating the current density is the quickest and most efficient way to change the SOFC power. Meanwhile, manipulating the fuel flow is found to be the most efficient way to change the fuel utilization. In future work, it is recommended that such control strategies be further analyzed and compared in the context of a complete SOFC-GT system model.","PeriodicalId":15829,"journal":{"name":"Journal of Fuel Cell Science and Technology","volume":"12 1","pages":"031006"},"PeriodicalIF":0.0,"publicationDate":"2015-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1115/1.4029877","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63489456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The United States (U.S.) Department of Energy (DOE)’s Pacific Northwest National Laboratory (PNNL) is spearheading a program with industry to deploy and independently monitor five kilowatt-electric (kWe) combined heat and power (CHP) fuel cell systems (FCSs) in light commercial buildings. This publication discusses results from PNNL’s research efforts to independently evaluate manufacturer-stated engineering, economic, and environmental performance of these CHP FCSs at installation sites. The analysis was done by developing parameters for economic comparison of CHP installations. Key thermodynamic terms are first defined, followed by an economic analysis using both a standard accounting approach and a management accounting approach. Key economic and environmental performance parameters are evaluated, including (1) the average per unit cost of the CHP FCSs per unit of power, (2) the average per unit cost of the CHP FCSs per unit of energy, (3) the change in greenhouse gas (GHG) and air pollution emissions with a switch from conventional power plants and furnaces to CHP FCSs; (4) the change in GHG mitigation costs from the switch; and (5) the change in human health costs related to air pollution. From the power perspective, the average per unit cost per unit of electrical power is estimated to span amore » range from $15–19,000/ kilowatt-electric (kWe) (depending on site-specific changes in installation, fuel, and other costs), while the average per unit cost of electrical and heat recovery power varies between $7,000 and $9,000/kW. From the energy perspective, the average per unit cost per unit of electrical energy ranges from $0.38 to $0.46/kilowatt-hour-electric (kWhe), while the average per unit cost per unit of electrical and heat recovery energy varies from $0.18 to $0.23/kWh. These values are calculated from engineering and economic performance data provided by the manufacturer (not independently measured data). The GHG emissions were estimated to decrease by one-third by shifting from a conventional energy system to a CHP FCS system. The GHG mitigation costs were also proportional to the changes in the GHG gas emissions. Human health costs were estimated to decrease significantly with a switch from a conventional system to a CHP FCS system.« less
{"title":"Energy System and Thermoeconomic Analysis of Combined Heat and Power High Temperature Proton Exchange Membrane Fuel Cell Systems for Light Commercial Buildings","authors":"W. Colella, S. Pilli","doi":"10.1115/1.4007273","DOIUrl":"https://doi.org/10.1115/1.4007273","url":null,"abstract":"The United States (U.S.) Department of Energy (DOE)’s Pacific Northwest National Laboratory (PNNL) is spearheading a program with industry to deploy and independently monitor five kilowatt-electric (kWe) combined heat and power (CHP) fuel cell systems (FCSs) in light commercial buildings. This publication discusses results from PNNL’s research efforts to independently evaluate manufacturer-stated engineering, economic, and environmental performance of these CHP FCSs at installation sites. The analysis was done by developing parameters for economic comparison of CHP installations. Key thermodynamic terms are first defined, followed by an economic analysis using both a standard accounting approach and a management accounting approach. Key economic and environmental performance parameters are evaluated, including (1) the average per unit cost of the CHP FCSs per unit of power, (2) the average per unit cost of the CHP FCSs per unit of energy, (3) the change in greenhouse gas (GHG) and air pollution emissions with a switch from conventional power plants and furnaces to CHP FCSs; (4) the change in GHG mitigation costs from the switch; and (5) the change in human health costs related to air pollution. From the power perspective, the average per unit cost per unit of electrical power is estimated to span amore » range from $15–19,000/ kilowatt-electric (kWe) (depending on site-specific changes in installation, fuel, and other costs), while the average per unit cost of electrical and heat recovery power varies between $7,000 and $9,000/kW. From the energy perspective, the average per unit cost per unit of electrical energy ranges from $0.38 to $0.46/kilowatt-hour-electric (kWhe), while the average per unit cost per unit of electrical and heat recovery energy varies from $0.18 to $0.23/kWh. These values are calculated from engineering and economic performance data provided by the manufacturer (not independently measured data). The GHG emissions were estimated to decrease by one-third by shifting from a conventional energy system to a CHP FCS system. The GHG mitigation costs were also proportional to the changes in the GHG gas emissions. Human health costs were estimated to decrease significantly with a switch from a conventional system to a CHP FCS system.« less","PeriodicalId":15829,"journal":{"name":"Journal of Fuel Cell Science and Technology","volume":"12 1","pages":"031008"},"PeriodicalIF":0.0,"publicationDate":"2015-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1115/1.4007273","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63474510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Too high stack temperature and insufficient reactant gas flow may lead to severe and irreversible damages in a real solid oxide fuel cell (SOFC) power system. Thus, fault monitoring and diagnosis technology is indispensable to improve the SOFC system reliability. A supervised self-organization map (SOM) model is proposed to diagnose the faults of the SOFC system in this paper. Using the supervised SOM model, the multidimensional testing data of the SOFC is mapped into a two-dimensional map, and the different region in the out map is represented for one fault mode. The method is evaluated using the data obtained from an SOFC mathematical model, and the results show that the supervised SOM analysis contributes on a very efficient way to the faults diagnosis of the SOFC system.
{"title":"Fault Diagnosis of Solid Oxide Fuel Cell Based on a Supervised Self-Organization Map Model","authors":"Xiao Juan Wu, Hongtan Liu","doi":"10.1115/1.4029070","DOIUrl":"https://doi.org/10.1115/1.4029070","url":null,"abstract":"Too high stack temperature and insufficient reactant gas flow may lead to severe and irreversible damages in a real solid oxide fuel cell (SOFC) power system. Thus, fault monitoring and diagnosis technology is indispensable to improve the SOFC system reliability. A supervised self-organization map (SOM) model is proposed to diagnose the faults of the SOFC system in this paper. Using the supervised SOM model, the multidimensional testing data of the SOFC is mapped into a two-dimensional map, and the different region in the out map is represented for one fault mode. The method is evaluated using the data obtained from an SOFC mathematical model, and the results show that the supervised SOM analysis contributes on a very efficient way to the faults diagnosis of the SOFC system.","PeriodicalId":15829,"journal":{"name":"Journal of Fuel Cell Science and Technology","volume":"12 1","pages":"031001"},"PeriodicalIF":0.0,"publicationDate":"2015-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1115/1.4029070","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63487747","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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