Energía y Ambiente (ITBA-KIT)

Permanent URI for this collection

http://ri.itba.edu.ar/handle/123456789/26

Browse

Now showing 1 - 20 of 68

A layout of the tritium plant subsystems for the european demonstration fusion power plant
(2023-03-28) Constantin, Federico Miguel; Schwenzer, Jonas
The European demonstration fusion power plant (EU-DEMO) project intends to prove the commercial viability of nuclear fusion as a source of safe and clean energy. This fusion power plant will be fueled by a 1:1 deuterium-tritium (hydrogen isotopes) mixture that will need to be recycled for environmental and economic reasons due to the low burn-up fraction. Tritium is a radioactive isotope that requires a special design of any handling facilities to be “tritium compatible” and a series of layers of protection to prevent any release of tritium to the environment above the permitted values. Moreover, tritium is scarcely available which makes it again crucial to design the tritium systems, the so called fuel cycle, such that the inventory is minimized. The EU-DEMO fuel cycle will be housed inside two buildings, the tokamak building and the tritium plant building. The first one will contain the reactor, its fueling systems and the direct internal recycling loop. The tritium plant building, which is the subject of this work, will accommodate an inner tritium plant loop and an outer tritium plant loop. In this thesis, a methodology for estimating the required footprint of the tritium plant and optimizing its layout is proposed. This is accomplished by identifying all the necessary equipment of the plant, estimating their physical dimensions, and allocating them into primary and secondary confinements (e.g. gloveboxes and rooms), for which their footprint and volume is obtained. By arranging these rooms inside a multistory building, the final layout is achieved. This methodology takes into consideration the fuel cycle processes and at the same time defines personnel and process safety, construction, operation and maintenance criteria to obtain an optimized layout suitable for the entire life cycle of the facility, while keeping in mind the need for minimizing the tritium inventory. Afterwards, this work puts forward a piping dimensioning strategy, defining design basis and calculation sequences supported on European Norms as well as optimization criteria to achieve a reasonably low tritium inventory in piping required to connect confinements and rooms. The presented tritium inventory determination focuses on the piping under normal operation of the plant, while the inventory inside the units is out of the scope of this work, even though it is taken into account for the development of the layout. The application of the developed methodologies resulted in the identification of 627 process equipment which have been grouped into 29 gloveboxes, 2 coldboxes and 19 metalboxes. These confinement structures can be housed inside a compact seven-story-building design, with a projected footprint of 2200 m2, a cumulative footprint of 11240 m2, an external volume of 57030 m3 and external dimensions of 35.8 m of height, 74.0 m of length and 30.9 m of width. Lastly, the resulting tritium inventory inside interconnecting pipes under normal operation is found to be in the order of 0.2 g with only 10 pipe types (outer diameter and thickness combinations).
An economic evaluation on hydrogen production technologies and hydrogen applications
(2023-04-02) Allende, Javier F.; Badea, A. F.
The main objective of the study is to present a comprehensive and, above all, updated overview of the hydrogen demand and supply situation. The physical and chemical properties of hydrogen are presented, together with an explanation of its major advantages and disadvantages as an energy carrier compared to other fuels currently in use. It also explains the importance of hydrogen on the world stage, as one of the main vectors for sustainable economic development worldwide. There are numerous uses for hydrogen nowadays. It can be used, for example, as a feedstock in several industrial processes, as an energy carrier or reserve, and as one of the main fuels to decarbonise transport. This work explains the current situation of hydrogen demand, showing the most relevant applications at present and those that are emerging as highly probable alternatives in the short term. Furthermore, estimates of future hydrogen demand are also presented. Regarding hydrogen production methods, firstly, a technical analysis is presented, explaining the characteristics of the different production methods available at present. Subsequently, an analysis of production costs is carried out, taking into account the main alternatives. A sensitivity analysis is also carried out on these alternatives to appreciate with clarity which are the factors that have the greatest impact on the final cost of hydrogen production for each method. One of the most notable conclusions of the report is the fact that, at current fossil fuel prices and associated emissions costs, zero- or low-emission hydrogen production methods are cost- competitive against hydrogen produced from natural gas (the most widely used technology today). It is also highlighted how the global context of recent years has led to an accelerated development of hydrogen technologies and their deployment.
Analysis and evaluation of Monika’s first result in bypass configuration
(2020) Gardella, Luciano Javier; Schulenberg, Thomas
El objetivo de esta tesis es mostrar, discutir y evaluar los resultados de la Central Eléctrica MoNiKa en régimen estacionario trabajando con diferentes partes de carga en operación de bypass. Los experimentos realizados para esta tesis durante el semestre de invierno de 2019, son los primeros resultados que salen de la instalación. MoNiKa fue autorizada para operar a finales de 2018, y hoy en día sigue en desarrollo. El trabajo actual, estudiará la planta de energía para definir su situación real. Las principales cuestiones a responder fueron la cuestión de la fiabilidad y la precisión de los datos medidos. Definir el grado de fiabilidad de las mediciones, es esencial para tener un punto de partida para llevar a cabo una correcta evaluación de la instalación. Así como las condiciones límite y los límites operacionales de la central. Cada prueba realizada en este trabajo contribuye a tener una mejor comprensión de la instalación y sus componentes. Además, contribuye a construir el conocimiento del MoNiKa. Y determinará la base para los próximos pasos de la investigación. Un software desarrollado por el instituto fue la principal herramienta utilizada para analizar la información obtenida de la instalación. GESI (Simulación Geotérmica). La definición de las necesidades de entrada para hacer coincidir el modelo con la instalación fue parte del desafío en este trabajo también. La comparación de los resultados del MoNiKa con el GESI se convierte en un proceso de retroalimentación. Donde al final de cada paso, se obtuvo una mejor comprensión de la instalación. Como resultado, se estudió en profundidad toda la prosa, la central eléctrica, y se desarrolló un módulo de GESI para simular futuros escenarios de MoNiKa.
Analysis of performance and results of a steam jet ejector chiller (solar cooling)
(2016) Carbonare, Nicolás; Schmidt, Ferdinand; Özcan, Tunay
"The German Government has the objective the reduce by 11% the electrical energy consumption until 2020. Cooling facilities represent 14% of this consumption and bring huge savings potential. Solar thermal cooling and heating facilities promise primary energy savings compared to electric vapor compression chiller systems. The aim of this study is to analyze the results of the ProSolar Project, performed by the Hochschule Karlsruhe für Technik und Wirtschaft (HSKA). The project, that formally ended in October 2015, has led to the opportunity to build a solar cooling prototype, with the cooperation of Ritter Solar GmbH, GEA Wiegand and Fraunhofer UMSICHT. The objective was the development of a cooling and heating facility (steam jet ejector) with a low primary energy consumption, as it does not involve fossil fuels and only requires auxiliary electricity. The operational performance during the Summer 2015 period is analyzed and the results and overall system performance are compared with other solar cooling facilities in Europe (small and large scale). Advantages and drawbacks are highlighted and future possibilities based on the operational experience gained are also mentioned."
Applicability of a state-of-the-art engineering toolkit in the risk analysis of a prototypical Hydrogen refueling station
(2020) Ordóñez, Marco; Jordan, Thomas
En el desarrollo actual de los vehículos de celdas de combustible, las estaciones de servicio de hidrógeno desempeñan un papel importante como fuente directa de combustible. Uno de los principales aspectos que deben considerarse durante la instalación y el funcionamiento de una estación de servicio de hidrógeno es la seguridad tanto de la infraestructura como del personal que trabaja en ella. Sin embargo, la falta de herramientas de cálculo ampliamente aceptadas hace que las evaluaciones de riesgos sean difíciles de reproducir de una estación a otra. En el presente trabajo se estudia el potencial de aplicabilidad y se identifican las limitaciones de un software de cálculo ingenieril de código abierto para evaluación de riesgos, denominado HyRAM, para un proceso de evaluación de riesgos de una estación de servicio de hidrógeno prototípica basada en un caso real. Para ello, este trabajo inicia con una investigación de marco teórico sobre la metodología de evaluación de riesgos, el funcionamiento de una estación de servicio de hidrógeno y los peligros más relevantes presentes en este tipo de instalaciones. Para el análisis de consecuencias y probabilidades, luego se describen los principales modelos de cálculo de HyRAM y se seleccionan los escenarios de fallo a ser simulados con estos modelos. Se detallan las principales características de la estación prototipo de abastecimiento de hidrógeno. Se analizan dos conjuntos de escenarios de fugas de hidrógeno en la conexión roscada a la salida de la zona del compresor (donde interesan la gravedad de las consecuencias y la frecuencia de ocurrencia) mediante la radiación de la llama de jet para una ignición inmediata, y la sobrepresión para una combustión retardada. Para concluir la evaluación de riesgos, los resultados se convierten en una ponderación global de riesgos. Las principales conclusiones de este trabajo muestran como más importante que HyRAM es adecuada para un número acotado de escenarios, y que necesita incluir condiciones de borde adicionales para satisfacer el análisis de un caso real prototípico. En particular para el modelo de llama de jet, se observa la falta de un perfil de radiación de la llama que evolucione en el tiempo y facilite un cálculo preciso de la dosis térmica. Para el modelo de sobrepresión, el principal aspecto identificado es la falta de fiabilidad para describir los complejos fenómenos durante la evolución inicial de la mezcla aire-hidrógeno.
Automation and optimization of agricultural soil tillage applying machine learning based on machine- and process sensor systems
(2021) Kazenwadel, Benjamin; Geimer, Marcus; Stein, Alexander; Becker, Simon
Climate change and cost pressure lead to new environmental and economic challenges that increase the demand for innovative control systems to automate and optimize agricultural tasks. Automating speed control during power-intensive soil tillage can increase eciency and sustainability and counteract the lack of qualied personnel in agriculture. A survey was carried out focused on tillage by cultivating to obtain an overview of the challenges farmers face during their work, including their target preferences. Based on the obtained requirements for tillage by cultivating, a system was developed automating working depth control by online Lidar plane detection to ensure tillage quality and establish a basis for good plant growth. Automated speed control is realized based on an online-parameterized draft force and traction model combined with the usage of a neural network for fuel rate prediction. The network is trained oine and adaptable to the individual preferences of the farms and varying implements. Thereby, the operator can choose and customize optimization objectives such as fuel eciency, performance, or total cost. During the evaluation, the control system was tested with various objectives against a human driver and was able to perform optimization on the individual objective. Furthermore, the transferability of the system was demonstrated with the usage of another implement.
Catalytic cleaning process for high pressure electrolyzers
(2017) Dijk, Nicolás van; Jordan, Thomas; Grune, Joachim
"The on growing global energy demand and the increasing need to reduce greenhouse gas emissions in order to avoid the worst case scenarios of global warming, forces to introduce cleaner and more sustainable technologies and practices into all sector of the economy. Therefore, electricity produced by renewable sources is continuously increasing in the energy matrix worldwide. One drawback of the renewable energies is the generation intermittency. This issue positions hydrogen as one of the main characters to store the surplus energy and blend the uctuations by producing and storing it at high pressure. Hydrogen can be produced by splitting water using an electrolyzer. Moreover, in order to increase the power-to-gas eficiency, high pressure electrolyzer are being developed. Gas cross contamination in high pressure electrolyzers is a burden that needs to be tackled in Gas order to avoid unwanted ignition events. Therefore, a cleaning process needs to be implemented. In this master thesis a catalytic cleaning process is tested with an existent experimental set up. Tests are performed with pressures up to 90 bar and the behavior of the catalytic material is assessed. Results show v 10% efciency increase with pressure increase along the pressure range tested. It is found that pressure range is bounded due to experimental set-up limitations and modifications to the test facility are proposed."
CFD simulation of a hydrogen explosion experiment in an ISO container
(2017) Weber, Philipp; Schulenberg, Thomas; Jordan, Thomas; Kotchourko, Alexei
"The EU project HySEA is dedicated to explosion risk reduction by deflagration venting of industrial hydrogen installations. In 20-foot ISO containers, several experiments have been conducted to provide data for combustion model improvement and validation. The first experimental campaign included a blindprediction study concerning two lean premixed configurations. The hydrogen research group of IKET submitted a model prediction based on the in-house code COM3D. The experimental results were not matched. Therefore, the objective of this thesis was to improve the predictability of the CFD code by carrying out post-blind simulations. Over the course of this work, the roles of thermodiffusive instability and the turbulent flame speed model in the process of flame acceleration were analyzed and clarified. As a consequence, the numerical model for the transition from laminar to turbulent flame speed was developed and implemented in the COM3D code. Validating simulations demonstrated satisfactory agreement compared to the experimental results. This represents a first step toward extending the applicability of the code to a wider range of combustion scenarios."
Concept and design of a high power dense propulsion system for electric aircraft
(2023-10-02) Beneke, Lennart; Reuter, Steffen; Berg, Lars-Fredrik
The present thesis proposes a conceptual design of a tiltable propulsion system for the ALBACOPTER® 1.0, an eVTOL aircraft with a take-off mass of800 kg. Usually, the propulsion systems of eVTOLs are direct drives due to their simple design. However, since the propeller thrust in relation to the take-off mass is the most important criterion for vertical take-off aircraft, power-dense drives are of maximum importance. Therefore, a propeller drive concept combining a high-performance synchronous machine with a gearbox is developed and investigated with regard to its performance. For this purpose, all boundary conditions are determined. First, the propeller is simulated in order to define its relevant speeds and gear’s reduction ratio. Then the aerodynamic loads are estimated using data from wind tunnel tests and CFD simulations and qualitatively compared with own wind tunnel tests. It is shown that the moments induced by oblique propeller inflow play a significant role compared to the lateral forces. By calculating and classifying these and other potential loads, concepts for the drive train and the tilt actuator are developed and evaluated.
Conductivity measurements of electrode materials for sodium-ion batteries with aqueous electrolyte
(2017) Berardi, Juan Ignacio
For the industrial production of innovative energy storage systems such as the sodium-ion battery, high efficiency, high safety, long-term cycling performance and suitable cost production solutions are needed. The aim of this work is to evaluate the specific electrical conductivity of several electrode printing pastes in different combinations in order to find the most acceptable one. Moreover, a measurement method that can simulate - on a smaller scale - the working conditions of the customized battery design created by Fraunhofer ISE needs to be chosen or developed.
Decarbonisation of the Argentinian transport sector by the introduction of battery electric vehicles
(2018) Costantini, Patricio; Turturro, Gastón Andrés
"The thermochemical decomposition of beech wood biomass results in a poor quality bio-oil, which cannot be directly used in diesel engines. In order to make this oil resemble liquid fossil fuels, an upgrading technique should be applied. Among the available possibilities, hydrodeoxygenation (the removal of oxygen and saturation of double bonds through high pressure hydrogen) appears to be the most auspicious route to produce biofuels. Besides, this method requires a catalyst to increase the activity, which could be reused in further upgrading reactions so as to minimize the generation of waste material. In this work, four nickel-based catalysts were evaluated for the hydrodeoxygenation of beech wood bio-oil. After being synthesized, their superficial and compositional characteristics were assessed. Once the upgrading reaction was performed for the pyrolysis oil, the resulting products (upgraded bio-oil, aqueous phase and gas fraction) were separately analyzed. Considering the obtained results, the catalyst with the best upgrading performance was selected in order to regenerate and use it in further hydrodeoxygenation reactions. The catalyst selection was based on upgraded bio-oil, catalyst and reaction factors. Parameters such as carbon, oxygen and water content, HHV, pH value, poisoning and overall hydrogen consumption were taken into account. With the obtained results, Ni/SiO2 was chosen and therefore regenerated, which included the calcination and reduction of the spent catalyst before it was reused in a new hydrodeoxygenation reaction. Its performance was tested along three consecutive reactions and the quality of upgraded bio-oils corresponding to these cycles were evaluated. It could be concluded that Ni/SiO2 showed an improvement in the upgraded bio-oil quality next to a satisfactory performance after the three regeneration cycles, which points out that this particular catalyst can be regenerated and reused for a minimum of three times without significantly affecting the resulting upgraded bio-oil quality. Further characterization techniques should be performed in order to achieve a bigger understanding of the functioning of nickel-based catalysts and their reutilization in a larger number of consecutive upgrading reactions."
Design of a MoNiKa-ORC-turbine model in Simulink and comparison with experimental results
(2022) Filipe, Julia; Schulenberg, Thomas; Wiemer, Hans-Joachim
This work consists in the development of a computational model for the steam turbine currently operational in MoNiKa test facility plant, located in KIT-Campus Nord, Germany. Given that this corresponds to the first attempt to model the mentioned turbine, the selected approach was to elaborate a highly simplified model that considers the system as a whole, unique element, and therefore calculates in terms of the turbine’s inlet and outlet parameters. The development was made in Simulink, using a basic configuration of blocks and features, and also some specific parts were coded in MATLAB. The building process resulted firstly in a simplified version of the model that supports constant inputs and outputs and consequently is independent of time; and a final version that supports time-dependent inputs and outputs, and can be employed to simulate transient operation conditions. The validation was made using real data provided by the plant, with a selection of several cases that reflected different operation conditions. Final results showed that the model is successful in predicting stationary operation cases, and also achieved good results with some transient operation conditions that presented progressive variations. However, the model is not suitable for simulation of fast-varying conditions.
Design of a MoNiKa-turbine and condenser model in Modelica/Dymola and comparison with previous Simulink models and experimental results
(2023-03-06) Maier, Mirco; Wiemer, Hans-Joachim
To research optimization possibilities in supercritical ORC processes for geothermal power production the Modular low-Temperature Circuit Karlsruhe (MoNiKa) was built at Campus North of the Karlsruhe Institute of Technology. Several research tasks have been conducted over this installation focusing on individual components. The present master thesis describes the development of a coupled MoNiKa turbine-condenser model using the Modelica modeling language with the Dymola development environment. For thermodynamic components the commercial library TIL was used. To calculate the properties of the working fluid a Dymola-REFPROP interface was utilized. For the turbine model an empirical efficiency correlation of the MoNiKa turbine was developed from experimental data and implemented. The determination of the turbine inlet pressure is based on Stodola’s cone law which has been adjusted to the MoNiKa turbine in previous studies. To reduce computational time the input data has been pre-processed by applying filters. For the condenser model grid convergence studies were carried out to ensure precision and convergence. The simulation results of the developed models were compared to the results of previous Simulink models for turbine and condenser. The model was then validated using experimental data from several MoNiKa test runs from 08-10 November 2021 representing a range of different operating conditions. The quantitative and qualitative agreement of the simulated turbine shaft power with the experimental data could be improved compared to the previous models. The developed coupled turbine-condenser model is capable of providing close approximations of turbine shaft power and condenser outlet variables over a wide operating range of the MoNiKa plant. In addition, the computation time could be kept within reasonable limits to enable further extensions of the model to complete the MoNiKa cycle. The influence of individual input parameters on the output variables could be determined by means of a sensitivity study to guide further improvements in the measuring equipment.
Design study of the MoNiKa-ORC-turbine and comparison with experimental results
(2023-03-31) Niño Avella, Cristian Leonardo; Wiemer, Hans-Joachim
The main objective of the project is to develop, verify, and validate a MATLAB code which implements a mean-line analysis for the ORC-Turbine located in the MONIKA facility. The mean-line analysis method is a useful tool to design turbomachines. In this study it was used to simulate and analyze the performance and properties into the turbine, under different operating conditions by analyzing its properties in a mean radius for each one of the inside inlet and outlet cross sections of the stages. It was taken into consideration different loss correlations in order to achieve a better result. For the implementation of the mean-line analysis, the geometry and design properties for the ORC-Turbine were used, along with the experimental data obtained from the MONIKA facility in previous works. These data were used for the verification and validation process, ensuring that it accurately represents the behavior of the turbine under different scenarios. The MATLAB code was designed to implement the mean-line analysis method, which can simulate the performance of the ORC-Turbine under various operating conditions, such as different mass flow rates, inlet and outlet temperatures, and pressures. The results of the mean-line analysis showed that the developed code can accurately predict the performance and the properties of the ORC-Turbine, within a reasonable level of accuracy. The code can also be used to evaluate the impact of different design modifications, such as changes in the inlet and outlet thermodynamic properties of the fluid, on the turbine's performance.
Development and programming of an engineering tool regarding the heat radiation of Hydrogen vertical jet flames
(2020) Redosado León, Kevin Arturo; Jedicke, Olaf
Esta tesis tiene como objetivo entender, programar y desarrollar una herramienta de ingeniería sobre la radiación de las llamas de chorros verticales de hidrógeno. El lenguaje de programación de Python 3.7 es utilizado para programar la herramienta electronica. El trabajo actual estudia las propiedades termodinámicas del hidrógeno mientras se somete a un purgado. El análisis utiliza la ecuación de estado de Abel-Noble (EOS) para modelar el hidrógeno como un gas real. Con estas propiedades, diferentes parámetros sobre la llama de hidrógeno son hallados empleando diferentes correlaciones para determinar parámetros como la fracción de calor radiado (𝐹), la longitud de la llama (𝐿𝑓) y el flujo de calor de la radiación térmica (𝑄𝑟). Los resultados calculados se comparan con los datos experimentales para determinar su validez. El algoritmo utilizado para programar la herramienta electronica se muestra en este trabajo. Además, el procedimiento para resolver problemas como el refinamiento del pasos del tiempo y la resolución espacial se dan en este trabajo.
Development of a cell formation system
(2017) Kull, Tobías; Hiller, Marc; Baena, Manuel
"The aim of this work was to develop a cell formation system for cycling and formation of lithium ion cells. The uniqueness of this system is the possibility of energy recuperation from the discharg-ing process of the cell. Therefore, the hardware of an existing prototype was revised, and the cor-responding firmware was developed. For the safe operation of the cell formation system, a battery management system was designed, and a high-level system control was realized in MATLAB. Together with an intermediate electrical storage, a cell formation unit for the formation and cycling of a lithium ion cell was commissioned. Subsequently, the system was characterized regarding the charging and discharging behavior and the efficiency in charging and discharging mode. Conclud-ing, an economic evaluation was performed. The results suggest further development of the cell formation unit, as cost effectiveness is given depending on the choice of the intermediate electrical storage."
Development of a PV solar system to power an existing prototype of sodium chloride electrolyser
(2016) Ruck, Alexander; Lauretta, Juan Ricardo
"Esta tesis de maestría desarrolla un sistema fotovoltaico para alimentar un prototipo existente de electrolizador de cloruro de sodio, cuyo subproducto podría utilizarse para potabilizar agua. A efectos de dimensionar los paneles fotovoltaicos, se relevaron las características del electrolizador, se midieron parámetros de interés y se fijó para el proceso una duración de dos días, con la radiación solar promedio en Buenos Aires. Se consideró luego la radiación solar media en sitios con necesidad de agua potable, a fin de estimar la potencia eléctrica requerida en cada caso. Para conectar los paneles fotovoltaicos al electrolizador, se desarrollaron cinco conceptos diferentes. Estos fueron evaluados según criterios técnicos y económicos a fin de elegir el mejor. El trabajo realizado pretende ser una guía para futuros proyectos similares."
Development of an empirical body force model for plasma-based flow control in CFD applications
(2020) Günther, Maiken; Frohnapfel, Bettina; Kriegseis, Jochen
In the present work a new empirical model for the phase-resolved body forces of an DBD (Dielectric-Barrier-Discharge)-plasma actuator is developed. Therefore planar body forces have been derived from existing PIV (Particle-Image Velocimetry) measurements. A new approach is introduced that makes use of the similarity of fluid dynamic and electrostatic potential theory. The body forces are derived with the gradient of a scalar potential field that consists of superimposed single body force potentials. A system of linear equations describes the relation between the gradient field, the magnitude of the single potentials and the resulting body forces. A least-square fit of this equation system to the experimental body forces approximates the local magnitude of the potentials. The modeling results are compared to the experimental data regarding their phase-averaged and phase-resolved integral body force, the spatial body force distribution and the physical plausibility of the potential magnitudes. Centering around a baseline state, different numeric configurations of the model and their results are presented and discussed. This baseline state strongly indicates the validity of the developed approach, particularly regarding the resulting values of phase-resolved integral body forces. A future improvement of the numeric setup of the model is expected to prove the similarity of the distribution of body force potentials and free charges in the discharge area. This could lead towards a model that is independent from experimental validations. Finally, the new model is drawn into comparison with former modeling approaches by Shyy et al. [28], Suzen et al. [31] and Maden et al. [23]. Here it asserts itself with its unique capability to represent both components of phase-resolved body forces with good accuracy.
Development of an end-effector for an industrial robot for the automates integration of threaded inserts into a hybrid additive manufactoring process
(0022-01-28) von Deyn, Lennart
In this thesis, a novel approach to automatically install threaded inserts into additive manufactured parts is developed and validated. Such an approach is highly relevant in the context of process automation and production of function-integrated parts. Automated production in combination with additive manufacturing has the potential for resource and energy-efficient production. This is becoming an increasingly important factor during decision making, due to climate change. Furthermore, additive manufacturing can support the development of climate-friendly solutions across all fields of application, as it enables quickly adaptable designs and flexible production methods. In addition, new design approaches to produce function-integrated components are becoming available. Integrating mechanical and electrical functional components during manufacturing makes it possible to realise an efficient and cost-effective integration procedure. The Fused Filament Fabrication (FFF) process can be used for this purpose, as it allows easy automation and expandability compared to other additive processes, plus a wide variety of materials can be processed. Initial literature research on the state of the art shows, that currently no process has been described, that combines the FFF process with a subtractive process and conductive filament. The 4K-FFF unit, the subject of this thesis, offers a unique approach to the automated production of function-integrated components. The system consists of a multi-material FFF printer with a milling and handling module. Manufacturing inaccuracies resulting from the FFF process can be compensated by the milling module. An industrial robot on the handling module is used to add functional components to the process. This setup enables the fully automated production of function-integrated components. For fastening and contacting the function-integrated components, threaded inserts are used, which have to be installed manually due to a lack of a suitable alternative. Literature research shows that there are no methods for the automated installation of threaded inserts into individual components, which are common in FFF. This shortcoming is addressed in this thesis. A new end-effector for the industrial robot is developed, which can grip, heat and install threaded inserts into a component. In addition, a quick-change system is established. Both expansions further increase the degree of automation of the 4K-FFF unit. A parameter optimisation procedure is carried out to determine the ideal operating parameters for the new end-effector. The functionality of the development and the quick-change system is validated by the production of demonstrator components.
Development of the processing step from MOF to supported catalyst by electrospinning
(2022) Alvarez, Macarena; Maletzko, Annabelle
In order to increase the flexibility of renewable energies and improve their integration into existing energy grids, efficient intermediate storage is necessary. High-purity hydrogen produced in a water electrolysis cell is a suitable energy carrier. However, the use of some electrolyzers is associated with high costs due to the required use of precious metals as catalysts, while others have disadvantages in terms of load modulation. In this sense anion exchange membrane water electrolysis (AEMWE) arises as an attractive alternative technology that combines convenient features of other type of electrolyzers. Nevertheless, there is a necessity in improvement regarding the performance of AEMWE. The oxygen evolution reaction (OER) in the anode, is the major source of energy loss and therefore, there is potential to optimize OER catalysts. In this work, supported catalysts for the OER were developed using Metal-Organic Frameworks (MOF74) dopped with Ni and/or Co and fibers obtained from an electrospinning process, as supporting material. The MOFs were pyrolyzed to obtain a carbon scaffold with finely dispersed transition metals, as well as the polymer fibers, which structure the catalyst, allowing to tune conductivity and mass transport. Two different routes for combining the MOFs with the fibers were studied. In order to investigate the electrospinning process, polymer concentration, solvent, applied voltage and polymer were varied. The improved parameters were selected and Polyacrylonitrile (PAN) fibers were successfully electrospun and pyrolyzed. The MOFs were characterized physically, chemically and electrochemically. Pure Ni-MOF74 showed increasing current along the Cyclic Voltammetry cycles, reaching a mass-specific current of 732 mA mg -1 after 50 cycles. A supported catalyst was obtained after impregnation of the Ni-MOF74 over the pyrolyzed fibers and characterized. The combined catalyst showed a similar behavior compared with the pure Ni-MOF74.

Browse

Browsing Energía y Ambiente (ITBA-KIT) by Title

Results Per Page

Sort Options