Solid Oxide Fuel Cell Gas Turbine Research Articles

Optimizing a hybrid solid oxide fuel cell-gas turbine and geothermal energy system for enhanced efficiency and economic performance in power and hydrogen production scenario

Geothermal energy is utilized due to its sustainability and ability to provide a continuous low-emission source of heat, making it an ideal complement to the high-efficiency requirements of modern power plants. This study investigates a novel configuration coupling a solid oxide fuel cell-gas turbine unit with a dual-flash binary geothermal structure, enhanced by low-temperature electricity generation and hydrogen production subsystems. This configuration incorporates a regenerative steam Rankine cycle and a proton exchange membrane electrolyzer to achieve an efficient overall design. The setup is evaluated from thermodynamic and economic perspectives using a non-dominated sorting genetic algorithm-II for optimization. A complete parametric study assesses the sensitivity of critical variables. Multi-objective optimization is conducted across three scenarios considering exergy efficiency, hydrogen production rate, sum unit cost of products, and the payback period as objective functions. Results indicate an optimal exergy efficiency of 56.95% and a hydrogen production rate of 0.22 kg/h, with a product unit cost of $7.06/GJ and a payback period of 1.12 years. The parametric study underscores the significant impact of the number of solid oxide fuel cells and their existing density on key variables of the presented configuration. This study highlights the system's potential for efficient and economically feasible power and hydrogen production.

Potential of solid oxide fuel cells as marine engine assisted by combined cooling and power cogeneration systems

Switching to solid oxide fuel cell-gas turbine in marine applications can contribute to carbon reduction strategy. Integrating waste heat recovery technology can potentially meet the required cooling and power demands. This paper presents four combined cooling and power systems, each combining solid oxide fuel cell-gas turbine, supercritical CO2 cycle, and refrigeration cycle integration. First, the thermodynamic models of the four systems were constructed. Next, the performance of each integrated system was studied based on energy, exergy, economic, and environmental metrics. A multi-objective optimization approach was then applied to each system, balancing efficiency with cost. Results showed that the environmental penalty cost rate was 5.24 $/h at a fuel molar flow rate of 1.4 mol/s. The solid oxide fuel cell-gas turbine, regenerative supercritical CO2 Brayton cycle, and ejector expansion refrigeration cycle system offers the lowest cost rate of 44.40 $/h. Meanwhile, the solid oxide fuel cell-gas turbine, regenerative supercritical CO2 Brayton cycle, and absorption refrigeration cycle system achieves the highest energy efficiency (77.35 %) and cooling capacity (86.39 kW), indicating superior thermodynamic performance. This article provides a reference for the application of the solid oxide fuel cell-waste heat recovery system in marine transportation.

Characteristic Investigation of a Novel Aircraft SOFC/GT Hybrid System under Varying Operational Parameters

In this study, the implementation of a solid oxide fuel cell–gas turbine hybrid engine for primary propulsion and electric power generation in aircraft is investigated. The following three parameters, which are crucial in attaining optimal performance at any point in the flight profile, were identified: the oxygen-to-carbon ratio of the catalytic partial oxidation reformer, the fuel utilization factor of the fuel cell, and the airflow split ratio at the outlet of the high-pressure compressor. The study assesses the impact of varying these parameters within specified ranges on the performance of the hybrid system. At the design point, the system yielded a total power output of 1.96 MW, with 102.5 kW of electric power coming from the fuel cell and 7.9 kN (1.86 MW) of thrust power coming from the gas turbine. The results indicate that varying the oxygen-to-carbon ratio affected the fuel cell’s fuel utilization and resulted in a slight decrease in gas turbine thrust. The fuel utilization factor primarily affected the power output of the fuel cell stack, with a minor impact on thrust. Notably, varying the airflow split ratio showed the most significant influence on the overall system performance. This analysis provides insights into the system’s sensitivities and contributes to the development of more sustainable aircraft energy systems.

Thermodynamic analysis of a CCHP system with hydrogen production process by methane reforming enhanced by solar-assisted chemical looping adsorption

Combined cooling, heating and power (CCHP) systems integrated with renewable energy can greatly alleviate the fossil energy crisis and greenhouse effect. This work proposes a novel CCHP system, which consists of a solar-assisted sorption enhanced chemical looping steam methane reforming (SE-CL-SMR) hydrogen generation subsystem, a solid oxide fuel cell-gas turbine (SOFC-GT) subsystem, a dual-effect Li-Br absorption chiller/heat pump (DAC/H) subsystem, and a domestic hot water (DHW) subsystem. The impacts of the reformer temperature, pressure, the ratios of steam to carbon, calcium oxide to carbon, and nickel oxide to calcium oxide on the system’s methane conversion rate, hydrogen yield, hydrogen purity, and CO2 capture efficiency are also explored. While ensuring the hydrogen production effect and considering the lowest energy consumption, the optimal reforming temperature, reforming pressure, ratios of S/C, CaO/CH4 and NiO/CaO of the CCHP system are 560 °C, 1 atm, 3, 1 and 0.5, respectively. The system’s energy and exergy analysis is performed under the optimized operating condition. In comparison with the data of reference, the findings demonstrate that the system’s overall power generation efficiency is 53.23 %, the total energy utilization rate is 74.32 %, and the exergy efficiency is 52.87 %.

Performance Analysis and Optimization of SOFC/GT Hybrid Systems: A Review

This review provides an overview of the solid oxide fuel cell/gas turbine (SOFC/GT) hybrid system, highlighting its potential as a highly efficient and low-emission power generation technology. The operating principles and components of the SOFC/GT system, as well as the various configurations and integration strategies, are discussed. This review also examines the performance, advantages, and challenges of the SOFC/GT system, and discusses the research and development efforts aimed at improving its efficiency, reliability, and cost-effectiveness. This work provides an overview of the research conducted in the area of SOFC-based hybrid systems, which is expected to be beneficial for researchers who are interested in this area.

Effect of steam reinjection mass flow rate on the SOFC–GT system with steam reinjection

A solid oxide fuel cell (SOFC) is regarded as the first choice of high-efficiency and clean power generation technology in the 21st century due to its characteristics of high power generation efficiency and low pollutant emission. In this paper, hydrogen is used as a fuel for SOFCs using the EBSILON platform. A sensitivity analysis of the solid oxide fuel cell–gas turbine (SOFC–GT) system with steam reinjection is carried out to investigate the effect of the steam reinjection mass flow rate on the improvement of the electrical efficiency of the system and on the values of the other parameters. The results show that the variation in the steam reinjection mass flow rate has an effect on other parameters. Changes in several parameters affect the electrical efficiency of the system, which reaches 74.11% at a pressure ratio of 10, SOFC inlet temperature of 783.15 K, turbine back pressure of 70 kPa, and steam reinjection mass flow rate of 6.16 kg/s. Future research can optimize the overall parameter selection of the system in terms of economy and other aspects.

Performance analysis and multi-objective optimization of a novel poly-generation system integrating SOFC/GT with SCO2/HDH/ERC

The SOFC-based poly-generation system is an effective and environmental-friendly technology. To further improve energy efficiency of poly-generation system, a novel poly-generation system is developed based on solid oxide fuel cell/gas turbine (SOFC/GT) as the prime mover and supercritical carbon dioxide (SCO2) Brayton cycle, humidification and dehumidification (HDH) desalination and ejector refrigeration cycle (ERC) as the waste heat recovery units to produce power, cooling and freshwater. In the proposed system, a novel configuration of combining the SCO2 cycle with HDH is applied to recover the waste heat of SOFC/GT hybrid system. A mathematical model is developed to explore the system performances from the energy, exergy and economic perspectives. The effects of key parameters such as fuel flowrate, fuel utilization factor, SOFC operating pressure and temperature, and desalination top temperature on system performances are investigated. Multi-objectives optimization is conducted to obtain the optimal design parameters of the poly-generation system. The results show that the system net power output, cooling capacity and freshwater production are 273.769 kW, 12.997 kW and 24.23 g/s with the total cost being 14.01 $/h under the given condition, respectively. The electrical and exergy efficiencies and total gained output ratio of the system are 68.35 %, 67.23 % and 85.25 %, respectively. The parametric analysis indicates that an appropriate increase in fuel flowrate, fuel utilization factor and SOFC operating pressure and temperature can improve the electrical and exergy efficiency. The optimization results demonstrate that the system exergy efficiency and total cost are 67.48 % and 13.94 $/h.

Energy, Exergy, and Economic (3E) Analysis of SOFC-GT-ORC Hybrid Systems for Ammonia-Fueled Ships

A feasible solid oxide fuel cell–gas turbine–organic Rankine cycle (SOFC-GT-ORC) hybrid system for ammonia-fueled ships is presented in this study. To confirm the quantitative changes in thermodynamic performance and economics according to the system configuration, the system using ammonia fuel was simulated, and energy, exergy, and economic (3E) analyses were performed. As a result, the system economics generally had an inversely proportional relationship with the thermodynamic performance. System optimization was performed using a multi-objective genetic algorithm, setting the conflicting thermodynamic performance and economics as objective functions. The key results of this study obtained through optimization are as follows. With the introduction of the ORC, the SOFC-GT hybrid system thermal efficiency was increased by 2–6%, but the cost increased by 14–24%. In the SOFC-GT-ORC hybrid system, preferentially reducing the irreversibility of the SOFC, combustor, and ORC evaporator is advantageous in terms of performance. It is economical to use a moderate amount of SOFC fuel to achieve the target output; the cost of the ORC in the SOFC-GT-ORC hybrid system was approximately $23/h. This study is unique in that it systematically conducted a 3E analysis, which had not been previously well-performed for SOFC hybrid systems for ammonia-fueled ships.

Green hydrogen production and utilization in a novel SOFC/GT-based zero-carbon cogeneration system: A thermodynamic evaluation

Owing to the rise in global energy demand and environmental issues caused by energy supply and distribution, the attempt to design and develop novel eco-friendly and efficient cogeneration energy systems is one of the current research focuses. In this regard, this study presents a novel zero-carbon cogeneration energy system based on a pressurized solid oxide fuel cell-gas turbine (SOFC/GT) with a carbon capture and storage (CCS) process. The designed system accomplishes the joint production of energy (electricity, cooling, and heating) and matter (hydrogen, oxygen, condensate water recovery, and carbon dioxide). The proposed system also includes an advanced alkaline electrolyzer (AAE) system, an organic Rankine cycle, a LiBr-H2O absorption refrigeration cycle, and an LNG regasification cycle. A combination of a solar concentrated photovoltaic/thermal (CPV/T) system and wind turbines feed the AAE system, resulting in green hydrogen production. According to the simulation results, the suggested system under the design conditions generates power, cooling, and domestic hot water with 315 kW, 137.5 kW, and 1.012 kg/s, respectively. Also, this system can capture and store carbon dioxide, recover condensate water, and supply natural gas to the pipeline with values of 74.88 kg/h, 137.9 kg/h, and 624.24 kg/h, respectively. The results from thermodynamic analysis indicate that the CPV/T system has the highest contribution to the exergy destruction rate, and the presented cogeneration system operates with energy and exergy efficiency of 58.09% and 38.58%, respectively. Furthermore, a comprehensive parametric study has been conducted on the developed system in which the impact of important parameters, such as SOFC operating temperature, current density, solar radiation, air velocity, etc., on the output parameters of the system has been examined.

A novel multi-generation energy harvesting system integrating photovoltaic and solid oxide fuel cell technologies

This paper designs a new multi-generation system based on solar tower power supply, integrating a solid oxide fuel cell-gas turbine system, a supercritical recompressed carbon dioxide cycle, a Rankine cycle, an organic Rankine cycle, a compressed air energy storage system and a liquefied natural gas system. The aim is to overcome the intermittent and unstable nature of the solar power supply and ensure continuous power generation throughout the day, as well as improving the energy efficiency of the solar power system and minimising exhaust emissions from the integrated system. The system is modelled and evaluated in terms of energy, exergy, environment and economy. The results show the solar system energy efficiency of 10.09%, the total system energy efficiency of 19.28%, a round-trip efficiency of 58.66% and an exergetic round-trip efficiency of 52.06%, preventing the emission of 2090 tons of CO2 (a total of $50175 in environmental fines) per year. Finally, the proposed system was applied to a case study in the Xixiangtang district of Nanning, China, where the system, combined with real data, produced 24.8 MWh of electricity on the day with the highest direct of normal irradiance. In addition, the results of the economic analysis show the dynamic payback period is 6.9 years.

Thermodynamic analysis and optimization of a novel system integrating with solid oxide fuel cell-gas turbine and parabolic trough collector for using in sports buildings

This study aims at sport buildings and discussing mathematical models' applications focused on energy problems, both on the thermal and electrical sides. Methanol is a type of alcohol that can be used as an alternative fuel option. Solid oxide fuel cells are a type of fuel cell that have advantages over other types of fuel cells such as high efficiency and low emissions. Researchers are exploring the use of methanol in solid oxide fuel cells, because it can be converted into synthetic gas at certain temperatures using catalysts. This study focuses on a system that uses solar energy for combined cooling, cooling, heating, and power generation. Solar energy is a renewable and environmentally friendly source of energy. Methanol is synthesized and then converted into gases for use in solid oxide fuel cells. This process is called reforming. A fuel cell and a gas turbine system can increase power generation and provide heat for cooling with a conversion efficiency exceeding 64%, but 15% of energy is lost due to light and heat losses.

Techno-Economic Optimization of SOC Design and Operating Conditions in a Solid Oxide Fuel Cell-Gas Turbine Hybrid System

In a circular economy, highly efficient energy conversion systems are paramount to maximize resource utilization and minimize waste production, including carbon dioxide emissions. Solid oxide fuel cell-gas turbine hybrid systems, which can reach efficiencies of greater than 75%-LHV, have demonstrated to be a promising technology on the way to cleaner power generation. During the energy transition period, solid oxide fuel cell-gas turbine hybrid systems are likely to be operated on natural gas, however, their scalability allows these systems to reach very high efficiencies even at small scales, enabling the use of distributed resources such as biogas. In this presentation the authors will discuss key performance and economic metrics of small-scale (10 MW) advanced solid oxide fuel cell-gas turbine hybrid systems and their relation to cell design and system design elements. Current challenges in solid oxide fuel cell development include thermal cell management and production cost. This presentation presents findings of how cell design parameters influence thermal gradients and specific solid oxide cell costs on a $/kW-basis under hybrid system operating conditions. Moreover, specific cell components are identified, and effects will be discussed that can synergistically reduce thermal stress and specific cell cost at the same time. Informed by this analysis, the optimized cell design is integrated into a solid oxide fuel cell-gas turbine hybrid system in order to provide a comprehensive analysis of system operating conditions under consideration of thermal cell gradients, and new insights into economics and levelized cost of electricity are provided. The presentation will discuss the impact of fuel utilization, operating voltage, and operating pressure upon the heat integration, system’s operating window, and power output. A discussion of economic parameters will highlight cost driving factors to inform research on the next generation of solid oxide cells.

Enhancing geothermal ORC power generation with SOFC: A comprehensive parametric study on thermodynamic performance

Geothermal energy is a promising renewable energy source due to its abundant global reserves. However, most geothermal resources are of low grade, severely restricting their power generation capacity and efficiency. In this study, the geothermal organic Rankine cycle power generation system is combined with a solid oxide fuel cell-gas turbine system to improve the overall power supply and heat utilization efficiency. The heat source and cycle temperature are upgraded using high-temperature solid oxide fuel cell waste gas, and the combined system’s efficiency is further improved through cascade heat utilization. Electrochemical-thermodynamic models are developed for the proposed system, and energy-exergy analysis is carried out. The effects of fuel cell current density, operating temperature and geothermal grade on the combined system’s performance are comprehensively analyzed. Compared to the standalone geothermal system, the energy efficiency and output power of the organic Rankine cycle increase by 8.11% and 7.95% respectively in the baseline case. Under the lowest geothermal temperature condition, the cycle output power is improved by 22.64%. The net power of the combined system can vary from 358 kW to 846 kW by adjusting the fuel cell current density from 1000 A m−2 to 8000 A m−2, demonstrating a flexible power supply capability. The optimal solid oxide fuel cell operating temperature is 1023.15 K, resulting in the highest system overall energy efficiency of 14.85%. The presented work provides essential guidelines for improving geothermal power generation performance and designing applicable combined systems.

Conventional and advanced exergy and exergoeconomic analysis of a biomass gasification based SOFC/GT cogeneration system

In this paper, a small scale biomass gasification based solid oxide fuel cell/gas turbine (SOFC/GT) combined heat and power (CHP) plant is investigated by means of both conventional and advanced exergy and exergoeconomic analysis. A one-dimensional model of an internal reforming planner SOFC is employed to account for the temperature gradient within the fuel cell solid structure, which is maintained at the maximum allowable temperature gradient (150 K) under different operating conditions. Two main parameters of the gasification process, namely, air-to-steam ratio and modified equivalence ratio, are investigated, and the key parameters of the cycle exergy and exergoeconomic study are analyzed. Moreover, a multi-objective optimization procedure is applied to determine the unavoidable gasifier conditions required for the advanced exergy analysis of the system. The results of the conventional exergy and exergoeconomic analysis reveal that the highest rate of exergy destruction occurs in the gasifier, followed by the afterburner (AB) with 41.87% and 21.98%, respectively. Also, the lowest exergoeconomic factor is related to AB by 5.34%, followed by heat recovery steam generator (HRSG), gasifier, air compressor, and SOFC, which implies that the priority is to improve these components to reduce the exergy destruction cost rate. The results obtained from the advanced exergy and exergoeconomic analysis indicate that the most of the total exergy destruction rate is unavoidably in the CHP plant. The AB shows the least improvement potential in terms of reduction of the exergy destruction by almost 2% avoidable part, followed by Heat Exchanger 3 (H.X.3), gasifier, and SOFC duo to their lowest avoidable exergy destruction parts of almost 5%, 10% and 13%f respectively. Furthermore, the unavoidable part of the investment cost rate for all the components of the cogeneration plant is larger than the avoidable part, which means that it is difficult to reduce the investment cost rate of the system components. Meanwhile, the endogenous/exogenous analysis shows that the exergy destruction is completely endogenous for all components of the integrated plant, except for HRSG, GT, and HX1. Compressors and turbines have the highest potential to reduce endogenous exergy destruction. This is due to their higher avoidable endogenous exergy destruction. Reducing the investment cost rate seems difficult, as the main investment cost rate was found to be an unavoidable endogenous part for all system components. Finally, some results obtained from the advanced analysis approach are the opposite to those of the conventional method. This fact emphasizes that the results of conventional exergy analysis alone are insufficient and unreliable. For example, based on the advanced analysis perspective, the gas turbine and H.X.2 by 8.9% and 8.46% modified exergoeconomic factor, respectively, should be considered for reducing investment cost rate, while the conventional method gives opposite results.

Techno-Economic Analysis of Solid Oxide Fuel Cell-Gas Turbine Hybrid Systems for Stationary Power Applications Using Renewable Hydrogen

Solid oxide fuel cell (SOFC)–gas turbine (GT) hybrid systems can produce power at high electrical efficiencies while emitting virtually zero criteria pollutants (e.g., ozone, carbon monoxide, oxides of nitrogen and sulfur, and particulate matters). This study presents new insights into renewable hydrogen (RH2)-powered SOFC–GT hybrid systems with respect to their system configuration and techno-economic analysis motivated by the need for clean on-demand power. First, three system configurations are thermodynamically assessed: (I) a reference case with no SOFC off-gas recirculation, (II) a case with cathode off-gas recirculation, and (III) a case with anode off-gas recirculation. While these configurations have been studied in isolation, here we provide a detailed performance comparison. Moreover, a techno-economic analysis is conducted to study the economic competitiveness of RH2-fueled hybrid systems and the economies of scale by offering a comparison to natural gas (NG)-fueled systems. Results show that the case with anode off-gas recirculation, with 68.50%-lower heating value (LHV) at a 10 MW scale, has the highest efficiency among the studied scenarios. When moving from 10 MW to 50 MW, the efficiency increases to 70.22%-LHV. These high efficiency values make SOFC–GT hybrid systems highly attractive in the context of a circular economy as they outcompete most other power generation technologies. The cost-of-electricity (COE) is reduced by about 10% when moving from 10 MW to 50 MW, from USD 1976/kW to USD 1668/kW, respectively. Renewable H2 is expected to be economically competitive with NG by 2030, when the U.S. Department of Energy’s target of USD 1/kg RH2 is reached.

Thermo-economic analysis of a polygeneration system using biogas and waste tire based on the integration of solid oxide fuel cell, gas turbine, pyrolysis, and organic rankine cycle

To optimize the biogas power generation process and waste tire disposal, a novel polygeneration system has been conceptualized. The hybrid design comprises a solid oxide fuel cell-gas turbine subsystem, tire pyrolysis reactor, organic Rankine cycle, and waste heat recovery subsystem. The biogas is first utilized by the solid oxide fuel cell and gas turbine for power generation. Subsequently, the high-temperature exhaust is utilized to preheat the fuel and oxidant and to heat the pyrolysis reactor and organic Rankine cycle, thereby improving the power generation and energy conversion efficiency. A comprehensive case study has been carried out to verify technological and economic feasibility of the proposed scheme. The results demonstrate that the net energy efficiency of the system is 70.11 % with an exergy efficiency of 69.65 %, and that the hybrid system maintains a high level of performance even when the fuel cell operating temperature varies. The irreversibility mainly arises from the pyrolysis reactor, cell stack, and combustion chamber. The new design requires only an initial investment of 722.93 k$ and can be recovered in 5.09 years with a net present value of 1795.51 k$ over its 25-year service life. Therefore, the proposed system is highly promising and suitable for implementation.

Techno-Economic Optimization of SOC Design and Operating Conditions in a Solid Oxide Fuel Cell-Gas Turbine Hybrid System

Solid oxide fuel cell-gas turbine (SOFC-GT) hybrid systems can reach exceptionally high fuel-to-electricity conversion efficiencies while emitting virtually zero criteria pollutants. Due to these characteristics and their fuel-flexibility, SOFC-GT hybrid systems are seen as a key technology in sustainable power generation. In this work we explore SOFC cell design parameters that can synergistically reduce thermal stress and cost, as well as system-level design strategies to maximize economic performance. Results show that NG-fueled hybrid systems can reach efficiencies of 75%-LHV at a cost-of-electricity of 77.73 $/MWh. A similar biogas system with integrated anaerobic digester and biogas upgrading resulted in an efficiency of 53%-LHV and a cost-of-electricity of 137.19 $/MWh.

Waste heat recovery and exergy-based comparison of a conventional and a novel fuel cell integrated gas turbine hybrid configuration

In conventional gas-turbine cycles, a significant amount of heat is generated and gets unutilized, which results in lower thermal efficiency and higher exergy destruction. In this study, the available waste heat from the gas-turbine has been examined, considering the promising ways to utilize this waste heat. By integrating a waste heat recovery system, these losses can be overcome, and its exergy destruction can be minimized, and results in higher thermal efficiency. For this, a novel comparison has been made between simple gas-turbine without waste heat recovery, recuperated gas-turbine with single-stage recovery, and a solid oxide fuel cell recuperated gas-turbine with double-stage waste heat recovery hybrid system in terms of energy, exergy efficiency and exergy destruction. Using MATLAB, a detailed thermodynamic modelling has been done. The finding shows that a two-stage waste heat recovery system helps in reducing the temperature gradient at the inlet of fuel-cell, which makes the system more stable. At a pressure ratio of 10 and turbine inlet temperature 1250 K, maximum energy and exergy efficiency have been achieved for the proposed hybrid system, i.e., 65.33% and 61.639%, respectively. The waste heat recovery for recuperated gas-turbine is 119.462 kW, and for solid oxide fuel cell gas-turbine, is 1153.885 kW.

Exergoeconomic analysis and multi-objective optimization of a CCHP system based on SOFC/GT and transcritical CO2 power/refrigeration cycles

A CCHP (Combined Cooling, Heating and Power) system based on SOFC/GT (Solid Oxide Fuel Cell/Gas Turbine) and transcritical CO2 power/refrigeration cycles is proposed to efficiently provide cooling, heating and power for users under the principle of energy cascade utilization. The energy, exergy and exergoeconomic analysis is conducted to assess the effects of key parameters on the system’s thermal-economic performance. The simulation results demonstrate that the cooling, heating and net electricity outputs could reach 48.37 kW, 240.65 kW and 250.95 kW with a trigeneration cost per unit exergy of 37.12$/GJ, while the power generation and exergetic efficiencies could reach 62.65% and 62.27%. The annualized capital cost, O&M cost and fuel cost are 131 549$, 90 532$ and 162 375$, respectively. The NPV and payback period of the CCHP system are 502 824$ and 12.5 years. The effects of SOFC pressure, air flowrate, refrigerant flowrate and CO2 flowrate of the transcritical CO2 power cycle on the CCHP system characteristics are discussed. Furthermore, exergoeconomic and multi-objective optimization methods are used to find the final optimum operation condition with best results. A solution set in Pareto frontier with each fitness value superior to that of the design condition is obtained after optimization. Through the decision-making process, the total energy output and the exergy efficiency increase by 35.58 kW and 0.20%, respectively, while the unit exergy cost of trigeneration rises by 0.21$/GJ.

Comparative study of fuel types on solid oxide fuel cell – gas turbine hybrid system for electric propulsion aircraft

As a novel aviation power generation system, the solid oxide fuel cell-gas turbine (SOFC-GT) hybrid system has high electrical efficiency. Because aviation applications are sensitive to weight, the research of this system should not only consider thermodynamic performance but also focus on mass. Fuel is the energy source of the aircraft powered by SOFC-GT hybrid system, and the types not only affect the power generation performance and mass of the system but also determine the storage capacity. Therefore, the impact of fuel types on the SOFC-GT aircraft can be fully evaluated through the comprehensive analysis of the performance and mass. In this paper, the aircraft powered by SOFC-GT hybrid system fueled by hydrogen, ethanol and alkanes (n-decane, n-octane and liquid methane) are investigated. By establishing the thermodynamic model and mass model, the influence of fuel types on the performance of autothermal reforming, SOFC-GT hybrid system, and aircraft cruise is studied in sequence. The results show that in the reforming process, methane has the best hydrogen production performance and makes SOFC efficiency the highest. However, the performance of the SOFC-GT system is influenced by many factors. For non-hydrogen fuels, n-decane can achieve higher electrical efficiency, while methane has lower fuel consumption. The thermodynamic performance of the hydrogen-fueled system has absolute advantages, but it depends on the larger heat exchanger. Furthermore, for the electric regional aircraft powered by the SOFC-GT hybrid system, the range of aircraft fueled by hydrogen and ethanol is poor, and liquid hydrogen can only take advantage of its high energy density at lower payload due to the mass penalty of the cryogenic tanks, while n-decane and n-octane are superior. Meanwhile, CO2 emissions can still be significantly reduced by matching n-decane with the efficient SOFC-GT hybrid system.