@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} }