@article{GaertnerMarxSchubachGadereretal., author = {G{\"a}rtner, Sebastian and Marx-Schubach, Thomas and Gaderer, Matthias and Schmitz, Gerhard and Sterner, Michael}, title = {Techno-Economic Analysis of Carbon Dioxide Separation for an Innovative Energy Concept towards Low-Emission Glass Melting}, series = {energies}, volume = {16}, journal = {energies}, number = {5}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/en16052140}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-53627}, pages = {1 -- 25}, abstract = {The currently still high fossil energy demand is forcing the glass industry to search for innovative approaches for the reduction in CO2 emissions and the integration of renewable energy sources. In this paper, a novel power-to-methane concept is presented and discussed for this purpose. A special focus is on methods for the required CO2 capture from typical flue gases in the glass industry, which have hardly been explored to date. To close this research gap, process simulation models are developed to investigate post-combustion CO2 capture by absorption processes, followed by a techno-economic evaluation. Due to reduced flue gas volume, the designed CO2 capture plant is found to be much smaller (40 m3 absorber column volume) than absorption-based CO2 separation processes for power plants (12,560 m3 absorber column volume). As there are many options for waste heat utilization in the glass industry, the waste heat required for CO2 desorption can be generated in a particularly efficient and cost-effective way. The resulting CO2 separation costs range between 41 and 42 EUR/t CO2, depending on waste heat utilization for desorption. These costs are below the values of 50-65 EUR/t CO2 for comparable industrial applications. Despite these promising economic results, there are still some technical restrictions in terms of solvent degradation due to the high oxygen content in flue gas compositions. The results of this study point towards parametric studies for approaching these issues, such as the use of secondary and tertiary amines as solvents, or the optimization of operating conditions such as stripper pressure for further cost reductions potential.}, language = {en} } @article{GamischEttengruberGadereretal., author = {Gamisch, Bernd and Ettengruber, Stefan and Gaderer, Matthias and Dawoud, Belal}, title = {Dynamic simulation of isothermal and non-isothermal reduction and oxidation reactions of iron oxide for a hydrogen storage process}, series = {Renewable and Sustainable Energy}, volume = {1}, journal = {Renewable and Sustainable Energy}, number = {1}, publisher = {ELSP, International Open Science Platform}, doi = {10.55092/rse20230004}, abstract = {This work aims first to develop a dynamic lumped model for the isothermal reactions of hydrogen/steam with a single iron oxide/iron pellet inside a tubular reactor and to validate the model results against the experimental reaction kinetic data with the help of our STA device. To describe the temporal change in mass, and consequently, the temporal heat of reaction, the shrinking core model, based on the geometrical contracting sphere, is applied. It turned out that, the simulation model can reproduce the experimental, temporal concentration and temperature-dependent conversion rates with a maximum deviation of 4.6\% during the oxidation reactions and 3.1\% during the reduction reactions. In addition, a measured isothermal storage process comprising one reduction and one oxidation phase with a holding phase in between on a single reacting pellet could be reproduced with a maximum absolute deviation in the conversion rate of 1.5\%. Moreover, a lumped, non-isothermal simulation model for a pelletized tubular redox-reactor including 2kg of iron oxide pellets has been established, in which the heat of reaction, heat transfer to the ambient and heat transfer between the solid and gas phases are considered. The temporal courses of the outlet gas concentration as well as the temperatures of the gas stream and the solid material at a constant input gas flow rate and a constant reacting gas inlet concentration but different input gas temperatures are estimated. Because of the endothermic nature of the reduction reaction, the inlet reacting gas temperature shall be kept high to prevent the severe temperature drop in the solid phase and, consequently, the significant reduction of the reaction rate. Contrary to that, the oxidation process requires lower input gas temperatures to avoid the excessive overheating of the reaction mass and, consequently, the sintering of the reacting pellets. Finally, five of the previous reactors have been connected in series to explore the influence of the changing inlet gas temperatures and concentrations on the dynamic performance of each storage mass.}, language = {en} } @article{MikhaeilGadererDawoud, author = {Mikhaeil, Makram and Gaderer, Matthias and Dawoud, Belal}, title = {On the application of adsorber plate heat exchangers in thermally driven chillers}, series = {Applied Thermal Engineering}, volume = {220}, journal = {Applied Thermal Engineering}, publisher = {Elsevier}, doi = {10.1016/j.applthermaleng.2022.119713}, abstract = {The effect of both heat and mass transfer characteristic lengths (HTCL, MTCL) of two different adsorber plate heat exchangers (APHE), for application in an adsorption chiller, on the adsorption and desorption kinetics is investigated. Three representative test frames (TF1-TF3) are prepared to examine small-scale adsorbent samples of the microporous silica gel (Siogel of Oker-Chemie, Germany) applying the volumetric large-temperature-jump methodology at different operating conditions. Based on the obtained kinetic data, an analytical model has been developed to predict the specific cooling power (SCP) and the coefficient of performance (COP) of a single-bed adsorption chiller comprising the studied APHEs. It turned out that, within the tested range of HTCL and MTCL, it can be concluded that, the adsorption kinetics are mainly influenced by the MTCL, while the desorption kinetics are dominated by the HTCL of the adsorbent domain. Applying Siogel as loose pellets inside a newly introduced APHE results in of 423.3 and 182.7 W⋅kg-1, at the evaporator temperatures of 15 °C and 5 °C, respectively. Herein, the condenser and adsorber-end temperatures amount to 30 °C and the desorption-end temperature to 90 °C. The corresponding s amount to 0.50 and 0.40, respectively, which represent quite promising results for further design optimizations.}, language = {en} } @article{MikhaeilNowakPalombaetal., author = {Mikhaeil, Makram and Nowak, Sebastian and Palomba, Valeria and Frazzica, Andrea and Gaderer, Matthias and Dawoud, Belal}, title = {Experimental and analytical investigation of applying an asymmetric plate heat exchanger as an evaporator in a thermally driven adsorption appliance}, series = {Applied Thermal Engineering}, journal = {Applied Thermal Engineering}, number = {228}, publisher = {Elsevier}, doi = {10.1016/j.applthermaleng.2023.120525}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-61115}, abstract = {This communication presents an experimental and analytical study on the evaporation mechanism in a closed-structured asymmetric plate heat exchanger (PHE) employed as a stagnant water evaporator for the application in an adsorption heat transformation appliance. To this aim, an experimental unit is constructed, which comprises two identical PHEs, one acting as an vaporator/condenser and the second, as an adsorber/desorber. Two endoscopes are mounted inside the investigated evaporator to visualize the evaporation mechanism when performing adsorption-evaporation processes under different boundary conditions. It turned out that the evaporation mechanism is a partially covered, thin film evaporation. A heat transfer analysis is performed to evaluate the heat transfer coefficient of the thin film evaporation () inside the investigated evaporator, resulting in -values between 1330 and 160 [W∙m-2∙K-1] over the investigated adsorption-evaporation time. Correlating the obtained () to the film thickness and the wetted area results in -values between 0.34 and 0.78 [mm] and wetted to total area ratios of 0.78 to 0.16. Besides, an analytical model has been developed and introduced to correlate the overall evaporator heat transfer coefficient with the adsorption potential and the time rate of change of the water uptake.}, language = {en} } @article{MikhaeilGadererDawoud, author = {Mikhaeil, Makram and Gaderer, Matthias and Dawoud, Belal}, title = {Experimental Investigation of the Adsorption and Desorption Kinetics on an Open-Structured Asymmetric Plate Heat Exchanger; Matching Between Small-Scale and Full-Scale Results}, series = {Frontiers in Energy Research}, volume = {10}, journal = {Frontiers in Energy Research}, publisher = {Frontiers}, doi = {10.3389/fenrg.2022.818486}, pages = {1 -- 15}, abstract = {This paper introduces the results of an experimental study on the adsorption and desorption kinetics of a commercially available, open-structured asymmetric plate heat exchanger adapted to act as an adsorber/desorber for the application in adsorption heat transformation processes. In addition, a volumetric large temperature jump (V-LTJ) kinetic setup was applied to measure the adsorption and desorption kinetics of a small-scale adsorbent sample prepared dedicatedly to be representative for the adsorbent domain inside the investigated adsorber plate heat exchanger (APHE). All kinetic results of the small-scale adsorbent sample and the APHE were fitted into exponential forms with a single characteristic time constant (τ) with a coefficient of determination (R2) better than 0.9531. A very good matching between the small-scale and full-scale adsorption kinetic measurements was obtained, with an average relative deviation of 12.3\% in the obtained τ-values. In addition, the kinetic data of the small-scale adsorbent sample were utilized for estimating the expected specific instantaneous and moving average powers of the evaporator/condenser heat exchanger. The average relative deviation (ARD) between the moving average specific evaporator powers obtained from the small-scale and the full-scale measurements amounts between 5.4 and 15.1\%.}, language = {en} } @article{GamischHuberGadereretal., author = {Gamisch, Bernd and Huber, Lea and Gaderer, Matthias and Dawoud, Belal}, title = {On the Kinetic Mechanisms of the Reduction and Oxidation Reactions of Iron Oxide/Iron Pellets for a Hydrogen Storage Process}, series = {Energies}, volume = {15}, journal = {Energies}, number = {21}, publisher = {MDPI}, doi = {10.3390/en15218322}, abstract = {This work aims at investigating the kinetic mechanisms of the reduction/oxidation (redox) reactions of iron oxide/iron pellets under different operating conditions. The reaction principle is the basis of a thermochemical hydrogen storage system. To simulate the charging phase, a single pellet consisting of iron oxide (90\% Fe2O3, 10\% stabilising cement) is reduced with different hydrogen (H2) concentrations at temperatures between 600 and 800 °C. The discharge phase is initiated by the oxidation of the previously reduced pellet by water vapour (H2O) at different concentrations in the same temperature range. In both reactions, nitrogen (N2) is used as a carrier gas. The redox reactions have been experimentally measured in a thermogravimetric analyser (TGA) at a flow rate of 250 mL/min. An extensive literature review has been conducted on the existing reactions' kinetic mechanisms along with their applicability to describe the obtained results. It turned out that the measured kinetic results can be excellently described with the so-called shrinking core model. Using the geometrical contracting sphere reaction mechanism model, the concentration- and temperature-dependent reduction and oxidation rates can be reproduced with a maximum deviation of less than 5\%. In contrast to the reduction process, the temperature has a smaller effect on the oxidation reaction kinetics, which is attributed to 71\% less activation energy (Ea,Re=56.9 kJ/mol versus Ea,Ox=16.0 kJ/mol). The concentration of the reacting gas showed, however, an opposite trend: namely, to have an almost twofold impact on the oxidation reaction rate constant compared to the reduction rate constant.}, language = {en} } @article{SteiningerGadererDawoud, author = {Steininger, Peter and Gaderer, Matthias and Dawoud, Belal}, title = {Assessment of the Annual Transmission Heat Loss Reduction of a Refurbished Existing Building with an Advanced Solar Selective Thermal Insulation System}, series = {Sustainability}, volume = {13}, journal = {Sustainability}, number = {13}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/su13137336}, pages = {1 -- 19}, abstract = {A numerical parameter sensitivity analysis of the design parameters of the recently published solar selective thermal insulation system (SATIS) has been carried out to enhance its thermal and optical properties. It turned out that the insulation properties of SATIS can be effectively improved by reducing the length of the glass closure element. Increasing the area share of the light conducting elements (LCEs) and decreasing their length-to-diameter (L/D) ratio were identified as key parameters in order to increase the solar gain. Two SATIS variants were compared with the same wall insulation without SATIS in a yearly energetic performance assessment. The SATIS variant with 10 mm length of the closure element, 44.2\% area share of LCE, as well as front and rear diameters of 12 mm/9 mm shows an 11.8\% lower transmission heat loss over the heating period than the wall insulation without SATIS. A new methodology was developed to enable the implementation of the computed solar gains of SATIS in 1D simulation tools. The result is a radiant heat flow map for integration as a heat source in 1D simulation models. A comparison between the 1D and 3D models of the inside wall heat fluxes showed an integral yearly agreement of 98\%.}, language = {en} } @article{GamischGadererDawoud, author = {Gamisch, Bernd and Gaderer, Matthias and Dawoud, Belal}, title = {On the Development of Thermochemical Hydrogen Storage: An Experimental Study of the Kinetics of the Redox Reactions under Different Operating Conditions}, series = {Applied Sciences}, volume = {11}, journal = {Applied Sciences}, number = {4}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/app11041623}, pages = {1 -- 15}, abstract = {This work aims at investigating the reduction/oxidation (redox) reaction kinetics on iron oxide pellets under different operating conditions of thermochemical hydrogen storage. In order to reduce the iron oxide pellets (90\% Fe2O3, 10\% stabilizing cement), hydrogen (H2) is applied in different concentrations with nitrogen (N2), as a carrier gas, at temperatures between between 700 ∘C and 900 ∘C, thus simulating the charging phase. The discharge phase is triggered by the flow of a mixture out of steam (H2O) and N2 at different concentrations in the same temperature range, resulting in the oxidizing of the previously reduced pellets. All investigations were carried out in a thermo-gravimetric analyzer (TGA) with a flow rate of 250mL/min. To describe the obtained kinetic results, a simplified analytical model, based on the linear driving force model, was developed. The investigated iron oxide pellets showed a stable redox performance of 23.8\% weight reduction/gain, which corresponds to a volumetric storage density of 2.8kWh/(L bulk), also after the 29 performed redox cycles. Recalling that there is no H2 stored during the storage phase but iron, the introduced hydrogen storage technology is deemed very promising for applications in urban areas as day-night or seasonal storage for green hydrogen.}, language = {en} } @article{SteiningerGadererSteffensetal., author = {Steininger, Peter and Gaderer, Matthias and Steffens, Oliver and Dawoud, Belal}, title = {Experimental and Numerical Study on the Heat Transfer Characteristics of a Newly-Developed Solar Active Thermal Insulation System}, series = {Buildings}, volume = {11}, journal = {Buildings}, number = {3}, publisher = {MDPI}, doi = {10.3390/buildings11030123}, pages = {1 -- 22}, abstract = {A newly-developed solar active thermal insulation system (SATIS) is introduced with the main objective to accomplish a highly-dependent total solar transmittance on the irradiation angle. SATIS is also designed to obtain the maximum transmittance at a prescribed design irradiation angle and to reduce it remarkably at higher irradiation angles. A purely mineral thermal insulation plaster with micro hollow glass spheres is applied to manufacture the investigated SATIS prototype. Light-conducting elements (LCEs) have been introduced into SATIS and suitable closing elements have been applied. The SATIS prototype has been investigated both experimentally and numerically. It turned out that the contributions of conduction, radiation and convection to the effective thermal conductivity of SATIS, without the closing elements (49 mWmK), amount to 86.2\%, 13.2\% and 0.6\%, respectively. The angle-dependent short-wave radiation exchange within the LCE has been investigated via ray tracing. At the incidence angle of 19\% (design angle), 27\% of the radiation within the LCE is absorbed by the absorber plate, resulting in measured and computed total solar energy transmittances of 11.2\%/11.7\%, respectively. For a typical summer irradiation angle of 60\%, 98\% of the incident radiation is absorbed by the surfaces at the entrance of the LCE. The corresponding total solar energy transmittance amounts to 2.9\%.}, language = {en} } @article{GaertnerRankHeberletal., author = {G{\"a}rtner, Sebastian and Rank, Daniel and Heberl, Michael and Gaderer, Matthias and Dawoud, Belal and Haumer, Anton and Sterner, Michael}, title = {Simulation and Techno-Economic Analysis of a Power-to-Hydrogen Process for Oxyfuel Glass Melting}, series = {Energies}, volume = {14}, journal = {Energies}, number = {24}, publisher = {MDPI}, doi = {10.3390/en14248603}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-22713}, abstract = {As an energy-intensive industry sector, the glass industry is strongly affected by the increasingly stringent climate protection targets. As established combustion-based production systems ensure high process stability and glass quality, an immediate switch to low greenhouse gas emission processes is difficult. To approach these challenges, this work investigates a step-by-step integration of a Power-to-Hydrogen concept into established oxyfuel glass melting processes using a simulation approach. This is complemented by a case study for economic analysis on a selected German glass industry site by simulating the power production of a nearby renewable energy park and subsequent optimization of the power-to-hydrogen plant performance and capacities. The results of this study indicate, that the proposed system can reduce specific carbon dioxide emissions by up to 60\%, while increasing specific energy demand by a maximum of 25\%. Investigations of the impact of altered combustion and furnace properties like adiabatic flame temperature (+25 °C), temperature efficiency (∆ξ = -0.003) and heat capacity flow ratio (∆zHL = -0.009) indicate that pure hydrogen-oxygen combustion has less impact on melting properties than assumed so far. Within the case study, high CO2 abatement costs of 295 €/t CO2-eq. were determined. This is mainly due to the insufficient performance of renewable energy sources. The correlations between process scaling and economic parameters presented in this study show promising potential for further economic optimization of the proposed energy system in the future.}, language = {en} }