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In future, heat pumps and shallow geothermal energy will play a central role in the decarbonization of the building and energy sector. The potentials of shallow geothermal energy have not been exploited so far, in particular due to the high complexity of planning and approval processes. In addition, the various stakeholders involved in the planning process create interfaces, which can lead to transfer gaps and barriers for an optimized system design. In order to raise the potentials and optimize the system design, a holistic planning process and the combination of different planning tools are necessary, which enable, among other things, geothermal site evaluations, the representation of the mutual thermal influence of geothermal borehole heat exchangers and their effects on neighboring properties, as well as the evaluation of geothermal systems under consideration of economic and ecological decision parameters. In this context, a simulation-based multi-level planning methodology is presented, which enables the holistic planning of geothermal heat pump systems with borehole heat exchangers on the scales of single buildings up to district level in the early planning phases. By integrating calculation tools for mapping the upper ground and subsurface into a closed simulation chain, existing transfer gaps between different trades can be closed. Using a prototypically implemented system configurator, geothermal heat pump systems can be designed in detail, compared with conventional systems, and evaluated on the basis of technical, energetic, economic, and ecological criteria. The combination of configuration, immediate result plotting and automatically triggered simulations running in the background enables an iterative and practical design process. In this context, a heat pump system model is presented which is adapted to the functionalities of the system configurator and specialized for the early planning process. This model includes thermal storage balances and control algorithms, is applicable on city district level and can be coupled bidirectionally to subsurface models. The tool chain's connection to an existing web- and GIS-based geoportal including databases enables a central data aggregation and geothermal site evaluations. This can provide tool-based support for the application and approval process of shallow geothermal systems and holistic planning approaches such as municipal heat planning. Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2023; Aachen : RWTH Aachen University 1 Online-Ressource : Illustrationen, Diagramme (2023). = Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2023 Published by RWTH Aachen University, Aachen

In future, heat pumps and shallow geothermal energy will play a central role in the decarbonization of the building and energy sector. The potentials of shallow geothermal energy have not been exploited so far, in particular due to the high complexity of planning and approval processes. In addition, the various stakeholders involved in the planning process create interfaces, which can lead to transfer gaps and barriers for an optimized system design. In order to raise the potentials and optimize the system design, a holistic planning process and the combination of different planning tools are necessary, which enable, among other things, geothermal site evaluations, the representation of the mutual thermal influence of geothermal borehole heat exchangers and their effects on neighboring properties, as well as the evaluation of geothermal systems under consideration of economic and ecological decision parameters. In this context, a simulation-based multi-level planning methodology is presented, which enables the holistic planning of geothermal heat pump systems with borehole heat exchangers on the scales of single buildings up to district level in the early planning phases. By integrating calculation tools for mapping the upper ground and subsurface into a closed simulation chain, existing transfer gaps between different trades can be closed. Using a prototypically implemented system configurator, geothermal heat pump systems can be designed in detail, compared with conventional systems, and evaluated on the basis of technical, energetic, economic, and ecological criteria. The combination of configuration, immediate result plotting and automatically triggered simulations running in the background enables an iterative and practical design process. In this context, a heat pump system model is presented which is adapted to the functionalities of the system configurator and specialized for the early planning process. This model includes thermal storage balances and control algorithms, is applicable on city district level and can be coupled bidirectionally to subsurface models. The tool chain's connection to an existing web- and GIS-based geoportal including databases enables a central data aggregation and geothermal site evaluations. This can provide tool-based support for the application and approval process of shallow geothermal systems and holistic planning approaches such as municipal heat planning. Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2023; Aachen : RWTH Aachen University 1 Online-Ressource : Illustrationen, Diagramme (2023). = Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2023 Published by RWTH Aachen University, Aachen

The replacement of internal combustion engines by electric motors has been identified as a way to achieve widely-accepted international climate protection goals. Especially in the material handling sector, vehicles with electric drives have gained increasing market acceptance over the past decades. However, the electrification of counterbalanced forklift trucks with high tonnages requires batteries with extended energy capacity. Higher energy capacity usually correlates with higher volume-to-surface ratios resulting in decreased heat dissipation and, therefore, increased average operating temperatures of the commonly used lead acid batteries. As a consequence, battery lifetime is greatly reduced. Without design changes, one possibility for avoiding high operating temperatures is an adapted battery management strategy. This thesis reports on results obtained with flooded lead acid batteries, demonstrating that, with management strategies which include operation in a partial state of charge, energy efficiencies can be increased from about 0.7 to about 0.85 with minimal impact on lifetime.

The replacement of internal combustion engines by electric motors has been identified as a way to achieve widely-accepted international climate protection goals. Especially in the material handling sector, vehicles with electric drives have gained increasing market acceptance over the past decades. However, the electrification of counterbalanced forklift trucks with high tonnages requires batteries with extended energy capacity. Higher energy capacity usually correlates with higher volume-to-surface ratios resulting in decreased heat dissipation and, therefore, increased average operating temperatures of the commonly used lead acid batteries. As a consequence, battery lifetime is greatly reduced. Without design changes, one possibility for avoiding high operating temperatures is an adapted battery management strategy. This thesis reports on results obtained with flooded lead acid batteries, demonstrating that, with management strategies which include operation in a partial state of charge, energy efficiencies can be increased from about 0.7 to about 0.85 with minimal impact on lifetime.

pnd - rethinking planning 2022(1), 104-123 (2022). special issue: "Transformatives Forschen trifft Stadtentwicklung : Einführung und Reflexion / herausgegeben von Laura Brings, Lea Fischer, Agnes Förster und Fee Thissen" Published by Rektor der RWTH Aachen University, Aachen

pnd - rethinking planning 2022(1), 104-123 (2022). special issue: "Transformatives Forschen trifft Stadtentwicklung : Einführung und Reflexion / herausgegeben von Laura Brings, Lea Fischer, Agnes Förster und Fee Thissen" Published by Rektor der RWTH Aachen University, Aachen

This work contains investigations on the effect of powdered activated carbon (PAC) on the effluent quality and operational safety of a membrane bioreactor (MBR), as well as its effects on sewage sludge quality. The tests to detect these effects were carried out in one of the four large-scale MBRs operated in parallel at an 80.000 p.e. WWTP sewage treatment plant in Kaarst. Comparative investigations without PACs were carried out in two other MBRs. The focus was on different dosing strategies in which the PAC was dosed into the activated sludge tank in proportion to the volume flow, continuously over time and in daily pulse dosings. The cleaning performance of the PAC-MBR was improved compared to the reference. The elimination of carbon compounds and especially the adsorption of trace organic substances was significantly increased at the low PAC dosing rates of 7±5 to 10±7 gPAC/m³ influent. The mean and maximum values for nitrogen compounds in the effluent were also lower in the PAC-MBR than in the MBR without PAC, while no significant change was observed for phosphorus.At similar PAC doses, only a slight difference between the dosing strategies was discernible. Overall, the continuous dosing showed the best organic carbon and trace organic substances elimination. Daily pulse dosing showed the highest system availability for PAC dosing due to the simple dosing technology.A better filterability of the activated sludge with PAC addition could be determined and was linked to a lower content of fouling-promoting substances. In addition, a reduction in the air requirement for nitrification aeration of the PAC-MBR was observed.An improvement in the thickening of the excess sludge via sieve belt thickener was observed. The improved dewaterability of the digested sludge could be demonstrated in the laboratory in semi-technical and in the large-scale tests. During a time of PAC dosing in all four MBRs of the WWTP, a clear improvement for the dewatering efficiency in the large-scale centrifuge was achieved at the tested PAC concentrations. The cost of PAC dosing into the biological stage is not determined by the investment costs, but largely by the operating costs from PAC dosing. Considering possible savings for the wastewater levy, aeration energy and sludge disposal costs, the additional costs for PAC dosing are reduced by approx. 50 to 80 %, depending on the scenario. The investigations carried out show a high technological potential. Membrane bioreactor technology has already been state of the art for 20 years and it is complemented and completed to a considerable extent by the dosing of PAC. Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen , 2023; Aachen : RWTH Aachen University 1 Online-Ressource : Illustrationen, Diagramme (2023). = Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2023 Published by RWTH Aachen University, Aachen

This work contains investigations on the effect of powdered activated carbon (PAC) on the effluent quality and operational safety of a membrane bioreactor (MBR), as well as its effects on sewage sludge quality. The tests to detect these effects were carried out in one of the four large-scale MBRs operated in parallel at an 80.000 p.e. WWTP sewage treatment plant in Kaarst. Comparative investigations without PACs were carried out in two other MBRs. The focus was on different dosing strategies in which the PAC was dosed into the activated sludge tank in proportion to the volume flow, continuously over time and in daily pulse dosings. The cleaning performance of the PAC-MBR was improved compared to the reference. The elimination of carbon compounds and especially the adsorption of trace organic substances was significantly increased at the low PAC dosing rates of 7±5 to 10±7 gPAC/m³ influent. The mean and maximum values for nitrogen compounds in the effluent were also lower in the PAC-MBR than in the MBR without PAC, while no significant change was observed for phosphorus.At similar PAC doses, only a slight difference between the dosing strategies was discernible. Overall, the continuous dosing showed the best organic carbon and trace organic substances elimination. Daily pulse dosing showed the highest system availability for PAC dosing due to the simple dosing technology.A better filterability of the activated sludge with PAC addition could be determined and was linked to a lower content of fouling-promoting substances. In addition, a reduction in the air requirement for nitrification aeration of the PAC-MBR was observed.An improvement in the thickening of the excess sludge via sieve belt thickener was observed. The improved dewaterability of the digested sludge could be demonstrated in the laboratory in semi-technical and in the large-scale tests. During a time of PAC dosing in all four MBRs of the WWTP, a clear improvement for the dewatering efficiency in the large-scale centrifuge was achieved at the tested PAC concentrations. The cost of PAC dosing into the biological stage is not determined by the investment costs, but largely by the operating costs from PAC dosing. Considering possible savings for the wastewater levy, aeration energy and sludge disposal costs, the additional costs for PAC dosing are reduced by approx. 50 to 80 %, depending on the scenario. The investigations carried out show a high technological potential. Membrane bioreactor technology has already been state of the art for 20 years and it is complemented and completed to a considerable extent by the dosing of PAC. Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen , 2023; Aachen : RWTH Aachen University 1 Online-Ressource : Illustrationen, Diagramme (2023). = Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2023 Published by RWTH Aachen University, Aachen

The present thesis deals with the development of tailor-made ruthenium catalysts for the selective conversion of carboxylic acids, esters and amides, based on the [Ru(Triphos)TMM] catalyst lead structure (TMM = trimethylenemethane, Triphos = 1,1,1-tris(diphenylphosphinomethyl)ethan).Chapter 1 describes the state-of-the-art in hydrogenation with molecular catalysts and the importance of catalytic reduction as a tool for the chemical transformation of polar bonds in laboratory as well as in industrial scale. The [Ru(Triphos)TMM] complex is a universal catalyst for the catalytic conversion of carboxylic acid derivatives, for the di-rect hydrogenation of CO2 to methanol, as well as for the direct methylation of aromatic amines using CO2 as a C1 building block. However, mechanistic investigations revealed that the catalyst deactivates irreversibly by forming an inactive ruthenium dimer in all catalytic transformations, thus preventing a general applicability.In order to prevent the catalyst from deactivating via dimerization, the ligand was chemically modified as described in chapter 2. The dimer formation should be blocked by the introduction of sterically demanding substituents to the aromatic backbone of the ligand, for this reason, a library of 7 triphos derivatives and their corresponding ruthenium complexes could be established. The molecular structures from single-crystal x-ray diffraction of the complexes emphasized that the meta-substituents of the newly developed Triphos Xyl (1,1,1-tris(3,5-dimethylphenylphosphinomethyl)ethan) showed a significantly increased shielding of the ruthenium center in comparison to the usual triphos ligand, paving the way for application in challenging reductive transfor-mations. Chapter 3 contains the detailed mechanistic characterization of the different catalyst species. The activation of [Ru(Triphos)TMM] in the presence of hydrogen leads to the formation of the hydride complex [Ru(Triphos)(H)2], the cationic complex [Ru(Triphos)(H)(H2)][NTf2] is formed in the presence of HNTf2. Moreover, the XRD-analysis of a ruthenium dimer showed that the meta-substituents of the Triphos Xyl ligand should have a major influence on the dimer formation. In selected catalytic reactions (chapter 4) the novel catalyst demonstrated remarkable activities in the hydrogenation of carboxylic acids, esters and amides. Moreover, it was shown by NMR-analysis that the dimer formation was completely prevented in a cata-lytic reaction by the introduction of the Triphos-Xyl ligand. Thus, the Triphos-Xyl ligand significantly improves the chemical stability, catalytic activity and selectivity in the hydrogenation of dimethyl itaconate, itaconic acid and N-acetanilide.

The present thesis deals with the development of tailor-made ruthenium catalysts for the selective conversion of carboxylic acids, esters and amides, based on the [Ru(Triphos)TMM] catalyst lead structure (TMM = trimethylenemethane, Triphos = 1,1,1-tris(diphenylphosphinomethyl)ethan).Chapter 1 describes the state-of-the-art in hydrogenation with molecular catalysts and the importance of catalytic reduction as a tool for the chemical transformation of polar bonds in laboratory as well as in industrial scale. The [Ru(Triphos)TMM] complex is a universal catalyst for the catalytic conversion of carboxylic acid derivatives, for the di-rect hydrogenation of CO2 to methanol, as well as for the direct methylation of aromatic amines using CO2 as a C1 building block. However, mechanistic investigations revealed that the catalyst deactivates irreversibly by forming an inactive ruthenium dimer in all catalytic transformations, thus preventing a general applicability.In order to prevent the catalyst from deactivating via dimerization, the ligand was chemically modified as described in chapter 2. The dimer formation should be blocked by the introduction of sterically demanding substituents to the aromatic backbone of the ligand, for this reason, a library of 7 triphos derivatives and their corresponding ruthenium complexes could be established. The molecular structures from single-crystal x-ray diffraction of the complexes emphasized that the meta-substituents of the newly developed Triphos Xyl (1,1,1-tris(3,5-dimethylphenylphosphinomethyl)ethan) showed a significantly increased shielding of the ruthenium center in comparison to the usual triphos ligand, paving the way for application in challenging reductive transfor-mations. Chapter 3 contains the detailed mechanistic characterization of the different catalyst species. The activation of [Ru(Triphos)TMM] in the presence of hydrogen leads to the formation of the hydride complex [Ru(Triphos)(H)2], the cationic complex [Ru(Triphos)(H)(H2)][NTf2] is formed in the presence of HNTf2. Moreover, the XRD-analysis of a ruthenium dimer showed that the meta-substituents of the Triphos Xyl ligand should have a major influence on the dimer formation. In selected catalytic reactions (chapter 4) the novel catalyst demonstrated remarkable activities in the hydrogenation of carboxylic acids, esters and amides. Moreover, it was shown by NMR-analysis that the dimer formation was completely prevented in a cata-lytic reaction by the introduction of the Triphos-Xyl ligand. Thus, the Triphos-Xyl ligand significantly improves the chemical stability, catalytic activity and selectivity in the hydrogenation of dimethyl itaconate, itaconic acid and N-acetanilide.