TY - GEN A1 - Berg, Heinz Peter A1 - Kleissl, Marko A1 - Himmelberg, Axel A1 - Lehmann, Mario A1 - Prechavut, Nontavut A1 - Vorpahl, Michael ED - Prukvilailert, Monchai T1 - Heat balancing of direct reforming fuel cells in MGT-SOFC hybrid systems T2 - 9th Thai Society of Mechanical Engineers, International Conference on Mechanical Engineering (TSME-ICoME 2018) 11–14 December 2018, Phuket, Thailand N2 - Solid oxide fuel cells convert chemical energy in electrical energy and are highly suitable for the conversion of hydrocarbon based fuels and products from PowerToGas conversions. Embedded in a micro gas turbine-cycle instead of the combustion chamber the heat energy of the injected fuel, released in the SOFC-Stack, can additionally converted into work and by a turbine-generator into electricity. In a compact system, SOFC stacks are designed to realize a direct steam-reforming process inside. In such direct-reforming fuel cell systems the SOFC operating temperature due to the heat demand for reforming, can be reduced to a value in the range of the outlet temperature of the downstream flow (650°C). If the cycle uses a recuperating system, the operating conditions of the SOFC can be realized without additional high-temperature heat exchanger systems. The system with an uncooled turbine, described in [1], just can reach the operating temperature with an additional high-temperature heat exchange. The system described in this publication does not require an additional high-temperature heat exchanger, because the X-value, as the ratio between the exchanged heat quantity and the required amount of heat to complete the MGT-cycle [2] due to the referring process, is nearly zero and can be realized via the inner container wall (of the MLC). The cycle is completed (between the SOFC and the turbine entry) by the heat input of an afterburner. Here the unreacted fuel of the SOFC fuel-stream is used to provide the necessary heat energy for the downstream turbo-generator-system. KW - MGT-SOFC KW - Heat balancing KW - simulation KW - thermodynamic cycle KW - effectivity Y1 - 2018 UR - https://iopscience.iop.org/article/10.1088/1757-899X/501/1/012007/meta U6 - https://doi.org/10.1088/1757-899X/501/1/012007 SN - 1757-899X SP - 50 EP - 60 PB - IOP Publishing/IOP Science CY - Bristol ET - 1. Auflage ER - TY - GEN A1 - Dückershoff, Roland A1 - Berg, Heinz Peter A1 - Himmelberg, Axel A1 - Lehmann, Mario A1 - Kleissl, Marko ED - Ashton, Anete T1 - Influence on the Electrical Efficiency of a Hybrid MGT-SOFC-System by μ-fogging in a-Two-Staged Compressor System T2 - IOP Conference Series: Materials Science and Engineering N2 - Hybrid combinations of solid oxide fuel cell and recuperated micro gas turbines can convert the chemical energy of hydrocarbon-based fuels in electrical energy with high electrical efficiency. With an integrated and improved cycle management, more than 70% of the energy content of the fuel could be converted. Therefore, the systems are highly suitable for the Power-To-Gas conversion. In particular, a pressure charging of the SOFC fuel cell leads to an increase in stack performance. By a downstream turbo set, after residual fuels are intentionally oxidized with an afterburner, additional electrical energy can be gained from the expansion of the hot exhaust gas stream and the overall efficiency can be increased. In order to increase the electrical efficiency of the system, it is proposed, to ensure the required compression of the process air in particular by a-two-staged turbo compressor with an intermediate cooling system. By thus achievable reduction of the dissipation of the compressor and by targeted condensation of finest drops in front of the second compressor stage affected by intermediate cooling, an increase in efficiency of the system is possible. This is achieved by targeted cooling of the process air behind a low pressure compression, so that it is saturated over 100% relative air humidity. As a result, a slightly supersaturated airflow is available for the second compressor stage, which enters the compressor after heat removal via an intermediate cooling having a small number of microdroplets. Therefore, the condensed water evaporates again by the heat of compression in the second stage and the compressed flow ultimately enters the recuperation at a lower temperature than during normal compression. Thus, more heat can be recovered within the recuperation system. Therefore, the electrical energy of the system can be produced having higher efficiency, because the heat dissipation of the overall system decreases. In this article it is presented, how such a process is thermodynamically modelled and how a technical realization can be built after optimization by simulations. Finally, in this study, the process-influencing factors are analyzed to show the highest possible electrical yield of such a system. KW - Micro Gasturbine, Hybrid, SOFC Fuel Cell, Fogging, Efficiency Y1 - 2020 UR - https://iopscience.iop.org/article/10.1088/1757-899X/886/1/012041 U6 - https://doi.org/10.1088/1757-899X/886/1/012041 SN - 1757-899X SP - 1 EP - 8 PB - IOP Science CY - Bristol ET - 1. Auflage ER - TY - GEN A1 - Dückershoff, Roland A1 - Berg, Peter A1 - Kleissl, Marko A1 - Himmelberg, Axel T1 - TURBO fuel cell as a bridging technology for decentralised power generation using hythane T2 - AIP Conference Proceedings N2 - The TURBO fuel cell is a hybrid combination of a micro-gas turbine (MGT) and solid oxide fuel cells (SOFC). With its high electrical efficiency and low line losses, it will contribute to an environmentally friendly, reliable and affordable energy supply in residential areas. Thanks to its high efficiency, it enables greater independence from fossil fuels. Furthermore, by choosing a fuel cell type that is embedded in a turbomachinery process, hybrid technology maximises fuel flexibility and ultimately enables the transition from the existing fossil natural gas economy to a hydrogen economy. Power-to-X" products from renewable energies can be converted into electrical energy with maximum efficiency. In this way, it contributes to stopping CO2 emissions by 2050. The turbo fuel cell supplies energy in a decentralised manner and therefore exactly where it is needed. The waste heat generated by the principle can be used for building air conditioning (heating or cooling). Thanks to the condensing technology, an overall efficiency of over 96% can be demonstrated. It also contributes to grid stability thanks to its high flexibility and cluster capability. When natural gas or green methane is used as a fuel gas in a TURBO fuel cell, a synthesis gas is produced from a CH4 partial flow via an integrated pre-reformer according to the principle of vapour reforming. This synthesis gas is fed to the high-temperature fuel cell for conversion into electricity. If a high proportion of hydrogen is added to this fuel gas, it is referred to as hythane. It is shown that when hythane is used in the turbo fuel cell up to a hydrogen content of 50 %, the very high efficiency of electricity generation by the TURBO fuel cell is maintained. The introduction of this technology can drive forward the decarbonisation of the energy industry. This demonstrates how important this technology is for the introduction of a hydrogen economy utilising existing infrastructures. Y1 - 2024 U6 - https://doi.org/10.1063/5.0237467 SN - 1551-7616 SN - 0094-243X VL - 3236 (2024) IS - 1 SP - 080009-1 EP - 080009-8 PB - AIP Publishing ET - 1 ER - TY - GEN A1 - Dückershoff, Roland A1 - Berg, Heinz Peter A1 - Kleissl, Marko A1 - Walther, Aniko A1 - Himmelberg, Axel T1 - Flexibilization of an MGT-SOFC hybrid system for electricity and hydrogen production for the realization of a sustainable hydrogen economy T2 - AIP Conference Proceedings N2 - The turbo fuel cell is a hybrid combination of a micro-gas turbine (MGT) and solid oxide fuel cells (SOFC). It will contribute to an environmentally friendly, reliable and affordable energy supply due to its high electrical efficiency and low line losses in close proximity to residential districts. The turbo fuel cell (MGT-SOFC hybrid system) makes it possible to increase independence from fossil fuels by choosing a fuel cell type with maximum fuel flexibility embedded in a turbo machine process. This hybrid technology makes it possible to transform the existing fossil gas economy into a hydrogen economy. This technology converts products from "power-to-X-gas" conversions from renewable energies into electrical energy with the highest conversion efficiency and thus contributes to the goal of stopping CO2 emissions by 2050. The turbo fuel cell supplies energy exactly where it is needed. The principle-related waste heat can be used for building air conditioning (heating or cooling) systems. Thanks to the condensing technology, an overall efficiency of over 96% can thus be demonstrated. Additionally, it contributes to grid stability through high flexibility and cluster capability. For methane to be converted into electricity in a turbo fuel cell, a synthesis gas is generated from a CH4 partial flow via an integrated pre-reformer according to the principle of steam reforming. Through high-temperature separation after the pre- reformer, hydrogen can be extracted from the synthesis gas and discharged for use in other applications (e.g., hydrogen mobility). Hydrogen extraction does not lead to a deterioration of electrical efficiency, which is about 70% in the system under consideration. In the living spaces of tomorrow, hydrogen and electrical energy for mobility can thus be provided even before the realisation of a supra-regional hydrogen supply economy. Decarbonisation of the energy economy can be advanced through the introduction of this technology. In this publication, it is shown how important this technology is for the introduction of a hydrogen economy with the inclusion of existing infrastructure. Y1 - 2024 U6 - https://doi.org/10.1063/5.0205000 VL - 3086 (2024) IS - 1 ER - TY - GEN A1 - Berg, Heinz Peter A1 - Himmelberg, Axel A1 - Dückershoff, Roland A1 - Kleissl, Marko A1 - Ring, Uwe T1 - Simulations using dimensionless key figures for the design and optimization of compact, hybrid MGT-SOFC systems of the “Turbo Fuel Cell” type for high efficiency T2 - 14th European Conference on Turbomachinery Fluid dynamics & Thermodynamics : ECT14, April 12-16 2021; Gdansk, Poland N2 - The "Turbo Fuel Cell" represents a highly integrated and highly compact technology system of a micro gas turbine fuel cell cycle (MGT-SOFC). It provides the solution for a highly efficient reverse electricity generation with an electrical efficiency of at least 68% (status 2020-21) to approx. 75-80% (in the future). In the context of industrial research on such a hybrid process, adapted, dimensionless parameters should be used in the design and optimization of the overall system. As an example, simulations of thermally optimized solutions to improve the energy yield using various dimensionless key figures are presented. Above all, heat integration measures enable an increase in system efficiency and a reduction in primary energy input. On the basis of exergetic analyzes by use of a modified Heat Balance Factor Y, as presented at ETC12, and the consideration of the SOFC enthalpy spread j, as well as a highly integrative use of the High Temperature Heat Exchanger Function F, it is shown how the hybrid cycle process efficiency can be optimized through innovative coupling of the individual heat flows. Measures to change the hybrid process can be used to deliberately shift the useful energy from the predominant heat yield in order to optimize electrical efficiency. A developed system enables primary energy to be used with the highest possible efficiency. The primary fuel used here is gaseous primary energy in the form of methane (natural gas) and hydrogen from renewable sources. Treatment mechanisms, such as the reforming of the methane used, and the targeted use of modern heat insulation and recovery mechanisms also have been considered. For the optimized hybrid system, total electrical efficiencies of more than 68% could be demonstrated and additional thermal energy for heating purposes could be extracted. Ultimately, overall efficiencies for the utilization of the energy content of the primary energy of up to 97% can be achieved. Energy converters with a maximum system output of around 200-300kW were examined. In the near future, such plants can replace existing fossil power plants being part of decentralized network systems. By their flexibility, they can guarantee the necessary security of power supply. Y1 - 2021 U6 - https://doi.org/10.29008/ETC2021-644 ER -