TY - GEN A1 - Jana, Sayantan A1 - Chauhan, Nikhil A1 - Muthukumar, Palanisamy A1 - Röntzsch, Lars T1 - Transient analysis and performance prediction of a metal hydride based thermal energy storage system with Integrated cooling and heat upgradation T2 - Heat transfer engineering : an international journal N2 - This work embodies a numerical model development and simulation of a metal hydride-based thermal energy storage system with integrated cooling as well heat upgradation. The concept of this system is unique as it operates on thermal drive during the energy storage cycle while during the energy release cycle it is compressor-operated. The utility of the mechanical compressor in the system is two-fold i.e., one operation mode would harness cooling, and another operation mode would fetch heat upgradation. The numerical model devised is a lumped parameter model which solves for hydrogen concentration and temperature of the linked metal hydride reactors. The proposed thermal energy storage system is of 5 MJ capacity which engages tube bundle reactor settings for both high-temperature and low-temperature hydride alloys. Each energy storage and release cycles are simulated for a fixed duration of 10000 s. For a fixed heat supply and heat recovery temperatures of 623 K and 573 K, the system offered cooling coefficient of performance in the range of 1.43–1.58 at 283–293 K. Also, approximately 77% of the energy stored at 623 K could be retrieved at 573 K. In heat upgradation operation mode, 10–30 K temperature lift was accomplished. KW - Metal Hydride KW - Thermal Energy Storage System KW - Simulation Y1 - 2025 U6 - https://doi.org/10.1080/01457632.2025.2521599 SN - 0145-7632 SP - 1 EP - 13 PB - Taylor & Francis CY - London ER - TY - GEN A1 - Sakkas, Nikolaos Panagiotis A1 - Abang, Roger Atini T1 - Thermal load prediction of communal district heating systems by applying data-driven machine learning methods T2 - Energy Reports N2 - Load forecasting is an essential part of the operational management of combined heat and electrical power units, since a reliable hour- and day-ahead estimation of their thermal and electrical load can significantly improve their technical and economic performance, as well as their reliability. Among different types of prediction techniques, data-driven machine learning methods appear to be more suitable for load estimation in operational systems, compared to the classical forward approach. Research so far has been concentrated mainly on the magnitude of buildings with single load types. It has only been extended to a limited degree on the level of a district heating network where several end users with different characteristics merge into one bigger scale heat consumer (city or group of communities). In this study, artificial neural networks are utilized, to develop a load prediction model for district heating networks. A segmented analytical multi-phase approach is employed, to gradually optimize the predictor by varying the characteristics of the input variables and the structure of the neural network. The comparison against the load prediction time series generated by a local communal energy supplier using a commercial software reveals that, although the latter is enhanced by manual human corrections, the optimized fully automatic predictors developed in the present study generate a more reliable load forecast. Y1 - 2022 UR - https://www.sciencedirect.com/science/article/pii/S2352484721015213 U6 - https://doi.org/10.1016/j.egyr.2021.12.082 SN - 2352-4847 VL - 8 SP - 1883 EP - 1895 ER - TY - GEN A1 - Katzer, Christian A1 - Babul, Konrad A1 - Klatt, Matthias A1 - Krautz, Hans Joachim T1 - Quantitative und qualitative relationship between swirl burner operating conditions and pulverized coal flame length T2 - Fuel Processing Technology KW - Flame length KW - Flame stability KW - Swirl burner KW - Pulverized coal KW - Image processing Y1 - 2017 U6 - https://doi.org/10.1016/j.fuproc.2016.10.013 SN - 0378-3820 VL - 156 SP - 138 EP - 155 ER - TY - GEN A1 - Ziems, Christian A1 - Tannert, Daniel A1 - Krautz, Hans Joachim T1 - Project presentation: Design and installation of advanced high pressure alkaline electrolyzer-prototypes T2 - Energy Procedia Y1 - 2012 U6 - https://doi.org/10.1016/j.egypro.2012.09.087 SN - 1876-6102 VL - 29 SP - 744 EP - 753 ER - TY - GEN A1 - Kangwanpongpan, Tanin A1 - Correa da Silva, Rodrigo A1 - Krautz, Hans Joachim T1 - Prediction of oxy-coal combustion through an optimized weighted sum of gray gases model T2 - Energy : the international journal Y1 - 2011 U6 - https://doi.org/10.1016/j.energy.2011.06.010 SN - 0360-5442 VL - 41 IS - 1 SP - 244 EP - 251 ER - TY - GEN A1 - Missagia, Bruna A1 - Guerrero, Cinthya A1 - Narra, Satyanarayana A1 - Sun, Yaoming A1 - Ay, Peter A1 - Krautz, Hans Joachim T1 - Physicomechanical properties of rice husk pellets for energy generation Y1 - 2011 ER - TY - GEN A1 - Danila, Kevin A1 - Vollmer, Jan A1 - Kunz, Philip T1 - Performance evaluation of reanalysis models for upsampling of solar irradiance and wind speed data T2 - Renewable energy N2 - The transition to renewable energy sources is a cornerstone of modern energy system transformation. Yet, the integration of solar and wind power remains challenging due to limited availability of high-resolution time series data. Accurate modeling and forecasting of renewable energy generation are essential for grid stability, and the effective deployment of technologies such as water electrolysis. However, most available datasets are provided at coarse temporal resolutions, which restricts their utility for dynamic system analysis and hinders the development of robust operational strategies. This study addresses this critical gap by evaluating the performance of reanalysis models and introducing a statistical upsampling approach that generates data with 1-min resolution from reanalysis data with 1-h resolution using a first-order Markov chain Monte Carlo method. The method is validated against measured data. The normalized root-mean-square error of the simulated data is less than 10% and the mean intra-hour standard deviation differs from 4.8% to 9.1% compared to measured values for solar irradiance and wind speed. The generated data facilitates the optimization of system operation, and enhances the planning of sector-coupled infrastructures. Ultimately, this approach enables reliable integration of renewable energy despite limited data availability and thus contributes to the advancement of the sustainable energy transition. KW - Renewable energy source KW - Electrification KW - Reanalysis KW - Modeling KW - Monte Carlo KW - Markov Y1 - 2026 U6 - https://doi.org/10.1016/j.renene.2026.125301 SN - 0960-1481 VL - 261 SP - 1 EP - 13 PB - Elsevier BV CY - Amsterdam ER - TY - GEN A1 - Asegehegn, Teklay Weldeabzgi A1 - Schreiber, Matthias A1 - Krautz, Hans Joachim T1 - Numerical Study of Bubbling Gas-Solid Fluidized Beds Hydrodynamics: Influence of Immersed Horizontal Tubes and Data Analysis Y1 - 2011 UR - http://www.bepress.com/ijcre/vol9/A16 ER - TY - GEN A1 - Asegehegn, Teklay Weldeabzgi A1 - Schreiber, Matthias A1 - Krautz, Hans Joachim T1 - Numerical simulation and experimental validation of bubble behavior in 2D gas-solid fluidized beds with immersed horizontal tubes Y1 - 2011 U6 - https://doi.org/http://dx.doi.org/10.1016/j.ces.2011.07.056 ER - TY - GEN A1 - Schreiber, Matthias A1 - Asegehegn, Teklay Weldeabzgi A1 - Krautz, Hans Joachim T1 - Numerical and Experimental Investigation of Bubbling Gas-Solid Fluidized Beds with Dense Immersed Tube Bundles Y1 - 2011 ER - TY - GEN A1 - Kangwanpongpan, Tanin A1 - Franca, Francis H. R. A1 - Correa da Silva, Rodrigo A1 - Smith Schneider, Paulo A1 - Krautz, Hans Joachim T1 - New correlations for the weighted-sum-of-gray-gases model in oxy-fuel conditions based on HITEMP 2010 database T2 - International Journal of Heat and Mass Transfer Y1 - 2012 U6 - https://doi.org/10.1016/j.ijheatmasstransfer.2012.07.032 SN - 0017-9310 VL - 55 IS - 25-26 SP - 7419 EP - 7433 ER - TY - GEN A1 - Nimtz, Michael A1 - Klatt, Matthias A1 - Wiese, Bernd A1 - Kühn, Michael A1 - Krautz, Hans Joachim T1 - Modelling of the CO2 process- and transport chain in CCS systems - Examination of transport and storage processes T2 - Chemie der Erde - Geochemistry Y1 - 2010 U6 - https://doi.org/10.1016/j.chemer.2010.05.011 SN - 0009-2819 VL - 70 IS - 3 SP - 185 EP - 192 ER - TY - GEN A1 - Aha, Ulrich A1 - Findeisen, Alexander A1 - Krautz, Hans Joachim T1 - Maintenance optimization for large coal-fired power plants Y1 - 2011 ER - TY - GEN A1 - Danila, Kevin A1 - Kunz, Philip A1 - Röntzsch, Lars T1 - Low-temperature electrolysis model optimized for improved performance in dynamic simulations T2 - International journal of hydrogen energy N2 - Traditional hydrogen production methods contribute significantly to greenhouse gas emissions, making technological change essential. Water electrolysis powered by renewable energy offers a promising route for sustainable hydrogen production. However, the variability of renewables challenges efficient electrolyzer operation, often requiring detailed simulations with long time series and high computational effort. We present a dynamic model of a low-temperature electrolyzer system optimized for computational efficiency. The model increases computational speed by a factor of 1000 compared to full-balance models while maintaining accuracy above 99% in hydrogen prediction. The simplified model is used to investigate the benefits of modularization in large-scale hydrogen plants. Results show that modularization has a minor effect on overall output but significantly increases operational time. This extended production window can reduce the need for large-scale hydrogen storage, especially when integrated with a continuous hydrogen consumer. KW - Hydrogen KW - Water electrolysis KW - System model KW - Dynamic operation KW - Modularization KW - Sector coupling Y1 - 2026 U6 - https://doi.org/10.1016/j.ijhydene.2026.154294 SN - 0360-3199 VL - 223 SP - 1 EP - 12 PB - Elsevier BV CY - Amsterdam ER - TY - GEN A1 - Aha, Ulrich A1 - Findeisen, Alexander A1 - Krautz, Hans Joachim A1 - Kahlert, Joachim T1 - Korrosion und Instandhaltungsoptimierung CO2-armer Braunkohlekraftwerke unter geänderten Prozessbedingungen und -parametern Y1 - 2010 ER - TY - GEN A1 - Asegehegn, Teklay Weldeabzgi A1 - Schreiber, Matthias A1 - Krautz, Hans Joachim T1 - Investigation of bubble behavior in fluidized beds with and without immersed horizontal tubes using a digital image analysis technique Y1 - 2011 U6 - https://doi.org/http://dx.doi.org/10.1016/j.powtec.2011.03.025 ER - TY - GEN A1 - Asegehegn, Teklay Weldeabzgi A1 - Schreiber, Matthias A1 - Krautz, Hans Joachim T1 - Influence of two- and three-dimensional simulations on bubble behaviorin gas-solid fluidized beds with and without immersed horizontal tubes Y1 - 2012 U6 - https://doi.org/10.1016/j.powtec.2011.11.050 ER - TY - GEN A1 - Abang, Roger Atini A1 - Weiß, Sabine A1 - Krautz, Hans Joachim T1 - Impact of increased power plant cycling on the oxidation and corrosion of coal-fired superheater materials T2 - Fuel N2 - As power generation from variable renewable energy sources such as wind and solar power continues to increase in the future, fewer baseload power plants will be needed. As a result, high operational flexibility is becoming a vital requirement for conventional power plants to allow for the smooth integration of the variable renewable energy sources (v-RES) into the grid. To understand the impact of high operational flexibility (increased cycling) for coal-fired power plant materials, five commercial coal boiler superheater and reheater materials were investigated under isothermal and cyclic conditions for 1000 h each. The candidate alloys investigated were: T91, VM12-SHC, TP347-HFG, DMV304 HCu and DMV310 N. The results (weight change kinetics and metallographic analysis) after exposure at a metal surface temperature of 650 °C clearly showed the impact of increased flexibility on the corrosion and oxidation of the materials. Oxide growth (weight gain), metal loss, oxide spallation, and grain boundary attack were found to be more severe under cyclic conditions than under isothermal conditions. KW - Power plant flexibility, Isothermal oxidation, Cyclic oxidation, High temperature corrosion, Superheaters Y1 - 2018 U6 - https://doi.org/10.1016/j.fuel.2018.02.047 SN - 0016-2361 VL - 2018 IS - 220 SP - 521 EP - 534 ER - TY - GEN A1 - Merzsch, Matthias A1 - Lechner, Stefan A1 - Krautz, Hans Joachim T1 - Heat-transfer from single horizontal tubes in fluidized beds: Influence of tube diameter, moisture and diameter-definition by Geldart C fines content T2 - Powder Technology Y1 - 2012 U6 - https://doi.org/10.1016/j.powtec.2012.12.002 SN - 1873-328X ER - TY - GEN A1 - Lechner, Stefan A1 - Merzsch, Matthias A1 - Krautz, Hans Joachim T1 - Heat-transfer from horizontal tube bundles into fluidized beds with Geldart A lignite particles T2 - Powder Technology N2 - This work investigates the heat transfer mechanism in fluidized beds equipped with horizontal heat exchanger surfaces such as single tubes and especially tube bundles. Previous works were performed for varying operating conditions and solids' material properties, leading to a heterogeneous and therefore not applicable spectrum of derived correlations for the influence of tube diameter and tube bundle geometry on heat transfer. Based on a wide range validation of the correlation for the influence of single tube diameter on heat transfer coefficient, tube bundles with different tube diameters and horizontal and vertical spacings and alignments were investigated. Experiments were carried out using electrical heat transfer probes in a 0.15 m2 fluidized bed test facility at ambient conditions. Geldart A lignite and Geldart D solids were used in order to distinguish between predominant particle-convective and gas-convective heat transfer mechanisms. The tube bundle reduction factor on heat transfer coefficient was derived as a key parameter based on dimensionless geometric numbers. This factor predicts the reduction of the heat transfer coefficient compared to that of the single tube due to the particle and gas flow disturbances caused by the immersed tubes. Tube diameter as well as tube bundle geometry were successfully implemented into useful correlations for predicting tube bundles' heat transfer of gas–solid fluidized bed systems operating with fine particles. KW - Fluidized bed KW - Lignite KW - Drying KW - Heat transfer KW - Horizontal tubes KW - Tube bundle Y1 - 2014 U6 - https://doi.org/10.1016/j.powtec.2013.10.041 IS - 253 SP - 14 EP - 21 ER -