@misc{DueckershoffBiesoldBerg, author = {D{\"u}ckershoff, Roland and Biesold, Volker and Berg, Heinz Peter}, title = {Einsatz der Laser Patricle Image Velocimetry und der Ammoniak-Diazo-Messtechnik bei der Entwicklung moderner Hochdruckturbinen mit lokalem Druckaufbau und zeitlich begrenzter Str{\"o}mungsabl{\"o}sung}, language = {de} } @misc{RabeDueckershoffBerg, author = {Rabe, Guido and D{\"u}ckershoff, Roland and Berg, Heinz Peter}, title = {Ein Beitrag zur Schadstoffreduzierung zuk{\"u}nftiger Gasturbinen durch moderne K{\"u}hlverfahren}, language = {de} } @inproceedings{DueckershoffBiesoldBerg, author = {D{\"u}ckershoff, Roland and Biesold, Volker and Berg, Heinz Peter}, title = {Filmk{\"u}hlung bei verz{\"o}gerter Hauptstr{\"o}mung und lokaler Str{\"o}mungsabl{\"o}sung}, series = {Motto: Luft- und Raumfahrt - Made in Germany, Deutsche Technologie im internationalen Wettbewerb, Deutscher Luft- und Raumfahrtkongress 2001, Hamburg, 17. - 20. September 2001, Bd. 3}, booktitle = {Motto: Luft- und Raumfahrt - Made in Germany, Deutsche Technologie im internationalen Wettbewerb, Deutscher Luft- und Raumfahrtkongress 2001, Hamburg, 17. - 20. September 2001, Bd. 3}, publisher = {DGLR}, address = {Bonn}, pages = {1715 -- 1720}, language = {de} } @phdthesis{Dueckershoff, author = {D{\"u}ckershoff, Roland}, title = {Filmk{\"u}hlung in Gebieten mit verz{\"o}gerter Hauptstr{\"o}mung und in Bereichen lokaler Str{\"o}mungsabl{\"o}sung}, publisher = {Brandenburgische Techn. Univ.}, address = {Cottbus}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus-633}, language = {de} } @article{DueckershoffBiesoldBerg, author = {D{\"u}ckershoff, Roland and Biesold, Volker and Berg, Heinz Peter}, title = {Einsatz der Laser-Patricle-Image Velocimetry und der Ammoniak-Diazo-Messtechnik zur Untersuchung der Filmk{\"u}hlung zuk{\"u}nftiger Hochdruckturbinen}, language = {de} } @inproceedings{BergDueckershoffLehmannetal., author = {Berg, Peter and D{\"u}ckershoff, Roland and Lehmann, Mario and Prechavut, Nontavut}, title = {Micro Turbo-Fuel-Cell-Technology: Hybrid compact turbo machinery technology and thermodynamic aspects regarding design parameters of a high efficient MGT-SOFC-system}, series = {Proceedings of 12th European Conference on Turbomachinery Fluid dynamics \& Thermodynamics, ETC12, April 3 - 7, 2017, Stockholm, Sweden}, booktitle = {Proceedings of 12th European Conference on Turbomachinery Fluid dynamics \& Thermodynamics, ETC12, April 3 - 7, 2017, Stockholm, Sweden}, abstract = {The improvement of decentralised energy supply systems has received an important role in the recent years. One option therefore is the combination of SOFC with a recuperated MGT. Here, a new strategy for selecting the system parameters, such as the operating temperature of the SOFC, the turbine inlet temperature and the pressure ratio of the hybrid system, is presented. By introducing the heat ratio between the heat required to increase the process gas to the SOFC operating temperature and the heat required to raise the SOCF exhaust gas to the TIT, it was found that high efficiency (approx. 68\%) is realisable in a compact hybrid system today. Analysis also shows that the HEX-technology is needed to improve the system effectiveness. Also, high recirculation rates with lower TIT can be considered as the future development direction. In addition, a sample configuration of an oil-free MGT rotor unit with high speed foil bearings is presented.}, language = {en} } @misc{BergHimmelbergLehmannetal., author = {Berg, Heinz Peter and Himmelberg, Axel and Lehmann, Mario and D{\"u}ckershoff, Roland and Neumann, Mathias}, title = {The Turbo-Fuel-Cell 1.0 - family concept - Compact Micro Gas Turbine (MGT) - Solid Oxide Fuel Cell (SOFC) energy converters in the 100 - 500 kW electrical power range for the future}, series = {IOP conference series : Materials Science and Engineering}, volume = {297}, journal = {IOP conference series : Materials Science and Engineering}, issn = {1757-899X}, doi = {doi:10.1088/1757-899X/297/1/012004}, pages = {15}, abstract = {The "Turbo-Fuel-Cell-Technology" has been described as a MGT-SOFC hybrid system consisting of a recuperated micro gas turbine (MGT) process with an embedded solid oxide fuel cell (SOFC) subsystem. SOFC stacks are connected to "SOFC stack grapes" and are equipped with the so called HEXAR-Module. This module is composed of a high-temperature heat exchanger (HEX), an afterburner (A) and a steam reformer (R). The MGT-concept is based on a generator driven directly by the turbomachine and a recuperator, which returns the exhaust heat to the pressurized compressor outlet air. This provides the necessary base for a highly effective, pure MGT process and the "MGT-SOFC-high-efficiency process". This paper describes the concept and the thermodynamic background of a highly effective and compact design of the "Turbo-Fuel-Cell 1.0-Family" in the electrical performance class from 100 to 500kW. The technological state of the system is shown and a rating of the system with comparative parameters is discussed. It becomes visible that all necessary basic technologies should be available and that the technology (for stationary applications) can have the "entry into services (E.I.S.)" in the next 10 years. The MGT-SOFC performance map under different operation conditions is discussed. This article also provides an overview of the research on MGT-SOFC-Systems and the scenario of an energy supply network and a mobile energy conversion of the future introduction.}, language = {en} } @inproceedings{BergDueckershoffLehmannetal., author = {Berg, Heinz Peter and D{\"u}ckershoff, Roland and Lehmann, Mario and Prechavut, Nontavut}, title = {Micro Turbo-Fuel-Cell-Technology : Hybrid compact turbo machinery technology and thermodynamic aspects regarding design parameters of a high efficient MGT-SOFC-system}, series = {12th European Conference on Turbomachinery Fluid dynamics \& Thermodynamics}, booktitle = {12th European Conference on Turbomachinery Fluid dynamics \& Thermodynamics}, doi = {10.29008/ETC2017-266}, pages = {1 -- 12}, abstract = {The improvement of decentralised energy supply systems has received an important role in the recent years. One option is the combination of SOFC with recuperated MGT. Here, a new strategy for selecting the system parameters, such as the operating temperature of the SOFC, turbine inlet temperature and the pressure ratio of the hybrid system, is presented. By introducing the heat ratio between the heat required to increase the process gas to the SOFC operating temperature and the heat required to raise the SOCF exhaust gas to the TIT, it was found that high efficiency (approx. 68\%) is realisable in a compact hybrid system today. Analysis also shows that the HEX-technology is needed to improve the system effectiveness. Also, high recirculation rates with lower TIT can be considered as the future development direction. In addition, a sample configuration of an oil-free MGT rotor unit with high speed foil bearings is presented.}, language = {en} } @misc{DueckershoffBergHimmelbergetal., author = {D{\"u}ckershoff, Roland and Berg, Heinz Peter and Himmelberg, Axel and Lehmann, Mario and Kleissl, Marko}, title = {Influence on the Electrical Efficiency of a Hybrid MGT-SOFC-System by μ-fogging in a-Two-Staged Compressor System}, series = {IOP Conference Series: Materials Science and Engineering}, journal = {IOP Conference Series: Materials Science and Engineering}, editor = {Ashton, Anete}, edition = {1. Auflage}, publisher = {IOP Science}, address = {Bristol}, issn = {1757-899X}, doi = {10.1088/1757-899X/886/1/012041}, pages = {1 -- 8}, abstract = {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.}, language = {en} } @misc{BergDueckershoffHertrampfetal., author = {Berg, Heinz Peter and D{\"u}ckershoff, Roland and Hertrampf, Stefan and Kloshek, Alexander and Himmelberg, Axel}, title = {Development of an injector spark plug for the injection and ignition of gaseous fuels in internal combustion engines for use in conventional systems}, series = {AIP Conference Proceedings}, volume = {3626 (2024)}, journal = {AIP Conference Proceedings}, publisher = {AIP Publishing}, address = {Chiang Mai}, doi = {10.1063/5.0238165}, pages = {1 -- 8}, abstract = {An injection-ignition-system from an additive manufacturing process is presented with which gaseous fuels can be injected into the combustion chamber of an internal combustion engine under pressures of up to 80 bar and ignited. With the presented system, an improvement of the thermal efficiency can be achieved by a late fuel injection in the compression phase and with post-injection. With such a system, the engine becomes purely air-intake and a better filling level is achieved. Injection and ignition can take place simultaneously with this application. The system is designed with a high pressure stability for all components (200 bar) and can therefore also be used with higher compressions and combustion pressures. The spatial distribution of the fuel in the combustion chamber is achieved by angled fluid ports and also allows additional injections and ignitions in the power stroke and in the relief phase. This can improve thermal efficiency. A built-in annular channel also enables two different fuels to be injected as a mixing chamber. Finally, initial measurement results are shown for the use of hydrogen fuel in a single-cylinder engine. Indexing data and performance data of the engine indicate that the system can represent a significant increase in the efficiency of combustion engines with hydrogen fuel. Furthermore, the system can be used in conventional vehicle systems, whereby only fuel conditioning and control systems need to be adapted.}, language = {en} } @misc{DueckershoffBergKleissletal., author = {D{\"u}ckershoff, Roland and Berg, Peter and Kleissl, Marko and Himmelberg, Axel}, title = {TURBO fuel cell as a bridging technology for decentralised power generation using hythane}, series = {AIP Conference Proceedings}, volume = {3236 (2024)}, journal = {AIP Conference Proceedings}, number = {1}, edition = {1}, publisher = {AIP Publishing}, issn = {1551-7616}, doi = {10.1063/5.0237467}, pages = {080009-1 -- 080009-8}, abstract = {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.}, language = {en} } @misc{DueckershoffBergKleissletal., author = {D{\"u}ckershoff, Roland and Berg, Heinz Peter and Kleissl, Marko and Walther, Aniko and Himmelberg, Axel}, title = {Flexibilization of an MGT-SOFC hybrid system for electricity and hydrogen production for the realization of a sustainable hydrogen economy}, series = {AIP Conference Proceedings}, volume = {3086 (2024)}, journal = {AIP Conference Proceedings}, number = {1}, doi = {10.1063/5.0205000}, abstract = {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.}, language = {en} } @misc{BergHimmelbergDueckershoffetal., author = {Berg, Heinz Peter and Himmelberg, Axel and D{\"u}ckershoff, Roland and Kleissl, Marko and Ring, Uwe}, title = {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}, series = {14th European Conference on Turbomachinery Fluid dynamics \& Thermodynamics : ECT14, April 12-16 2021; Gdansk, Poland}, journal = {14th European Conference on Turbomachinery Fluid dynamics \& Thermodynamics : ECT14, April 12-16 2021; Gdansk, Poland}, doi = {10.29008/ETC2021-644}, abstract = {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.}, language = {en} } @misc{BergDueckershoffVorpahletal., author = {Berg, Heinz Peter and D{\"u}ckershoff, Roland and Vorpahl, M. and Himmelberg, Axel}, title = {Results of the measurement of SOFC fuel cell stacks under pressure conditions}, series = {IOP Conference Series: Materials Science and Engineering}, volume = {1137}, journal = {IOP Conference Series: Materials Science and Engineering}, doi = {10.1088/1757-899X/1137/1/012009}, pages = {1 -- 11}, abstract = {Results from the measurement of SOFC fuel cell stacks under pressure conditions are presented. As part of a measurement campaign, the operation of a stack system is investigated, particularly under the operating conditions of a recuperated micro gas turbine. Above all, the performance and effectiveness of selected stack types at various operating pressures and operating temperatures are measured. With the test facility set up for such investigations, cell systems could be examined under atmospheric conditions and with pressures of up to 5 bar. It is shown that in operating conditions under pressure, the output of the fuel cell systems are improving. From a gauge pressure of 4 bar, the performance curve is flattened and higher pressures only produced a marginal increase in performance. Furthermore, the cells tested at overpressure show a steady-state behavior more quickly under load change requirements than in atmospheric operation. This means that more flexible operating modes with faster response behavior can be realized. By choosing a suitable operating temperature, the efficiency of the system is further increasing. Care was taken to select the operating conditions of the cell systems so that coking can be prevented. Finally, a statement can be made about the pressure dependence of the fuel conversion rate. Parasitic reactions at the anode can be related to the power output. The tests carried out have shown that the high-temperature fuel cell is a promising service provider of the future. A combination of SOFC high-temperature fuel cells and micro gas turbines in one machine could, in addition to the internal provision of the required pressure, also lead to better dynamics of the entire system and increase the energy yield from the primary energy source.}, language = {en} }