Energía y Ambiente (ITBA-KIT)

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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.
Experimental set-up for bubble behaviour in a high pressure alkaline electrolyte
(2016) Frey, Félix; Jordan, Thomas; Orbaiz, Pedro
"The increase in the proportion of renewable energy in the energy matrix and associated unpredictable electricity surpluses, the need for efficient forms of energy storage raises. Due to high energy density and transportability, hydrogen plays an important role as energy storage. After the production of hydrogen by electrolysis a significant percentage of the stored energy is used for the compression of the hydrogen gas. Higher efficiencies are reached by high pressure electrolysis, because subsequently compression of the hydrogen gas is not necessary. In the course of a cooperation between the Institute of Nuclear and Energy Technologies (IKET) and the Instituto Tecnológico de Buenos Aires (ITBA), a high pressure elec-trolyser Experiment has been developed at ITBA. The particularity about this device besides the high working pressure, are glass windows in the taps in order to be able to analyse the behaviour of the gas bubbles. Experiments for the investigation of the bubble behaviour have been performed at IKET. This master thesis describes the development of the project, from the design and construction of the electrolyser at ITBA, to the execution of first series of experiments at IKET. First conclusions about the bubble behaviour are presented".
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."
Estudio de pre factibilidad para el reemplazo de energía térmica por eólica, en el yacimiento Cerro Dragón, Chubut-Santa Cruz, Argentina
(2016) García Bes, Patricio; Neffa, Patricio
"La humanidad necesita energía para su subsistencia, pero la quema de hidrocarburos para obtener dicha energía, trae aparejada la emisión de gases que propician el calentamiento global. En la búsqueda de reducir la quema de gas para incrementar su venta y evitar emisiones, se analizó la pre factibilidad técnico-económica de generar energía eléctrica a través de un parque eólico de 40 MW nominales en la Patagonia Argentina, con la finalidad de satisfacer parte de la demanda de energía eléctrica del Yacimiento de hidrocarburos “Cerro Dragón”. Esta energía reemplazaría a la generada en turbinas que funcionan con gas natural. El ingreso económico de este proyecto está dado por la venta del gas que se ahorra de quemar. Se pudo comprobar el alto potencial local para la generación de energía eólica y, tras haber establecido un diseño básico del parque, se pudo estimar los costos de inversión, costos operativos y cantidad de energía producida. Con estos valores se calculó la Tasa Interna de Retorno (TIR) para un rango de precios de venta de gas natural. Del estudio surge que se reduciría la quema de gas natural a razón de 136.200 m3/día, lo cual evitaría la emisión de 97,930 t CO2e por año. Con un valor de venta del gas de 6 USD/MMBtu, un factor de capacidad del 46 % y un CAPEX de 2000 a 1700 USD/kW, se obtuvo una TIR del orden del 2,8 – 5,3 %."
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."
Numerical and experimental analysis of check valves in fuel systems
(2017) Baumgartner, Jörg; Engelmann, Danilo
The objective of this thesis is to obtain a profound understanding about the efects incheck valves of carburetors and to integrate it in a one-dimensional analogous model. To review the model quality, a validation is being performed. For this purpose the results of 1D-simulations are compared to appropriate 3D-simulations. This shows a good qualitative and quantitative agreement. In addition, the validation is performed by means of measurements on a pulsation test bed. This reveals major deviations between measurements and 1D-simulation. Discussing potential reasons for these deviations leads to the presentation of a new concept for the test bed.
Evaluation of StarCCM+ to predict thermoacoustic instabilities using Large Eddy Simulation
(2017) Indlekofer, Thomas; Ariatabar, Behdad; Bauer, Hans-Jörg; Hermeth, Sebastian
"Self-sustained pressure and heat-release oscillations yielded by thermoacoustic coupling are a major problem of gas turbine operation and methods to predict them are needed. This work investigates the capabilities of Large Eddy Simulation (LES) in StarCCM+ to predict these instabilities in the academic Volvo bluff-body combustor. First, simplified cases are studied to assess boundary condition treatment and numerical accuracy of the methods available. The non-reactive operating point is predicted accurately, showing good agreement for velocity fields as well as the ability to predict the vortex shedding frequency in the intrinsically unsteady region of the recirculation zone. For a reacting-stable operating point the acceleration downstream of the bluff body is overpredicted and the flow fields are not predicted accurately. Low frequency oscillations of the unstable operating points are evidenced coincididing with experimental results and an acoustic analysis based on Comsol Multiphysics. Up to = 1:0 the coherence of the equivalence ratio and the magnitude of the instabilities is predicted qualitatively."
Experimental determination of single bubble behavior in a high-pressure optical alkaline electrolyzer
(2017) Estruga, Pablo José María; Jordan, Thomas
"The participation of renewable energy in the energetic matrix is increasing continuously and the electrical energy storage technologies will be crucial in the future energy sector scenario. With this technologies, it is possible to regulate the fluctuating electrical energy generation that renewable energy sources present. Under the “Power to gas” concept, hydrogen can be generated with the surplus of those sources (e.g. solar and wind power). Thus, it is essential to increase the efficiency of the storage technologies. The generation of hydrogen by means of high pressure electrolysis is presented as a possible solution. This master thesis was done within the cooperation program between the Institute of Nuclear and Energy Technologies (IKET) and the Instituto Tecnológico de Buenos Aires (ITBA). Experiments were performed with an alkaline high-pressure experimental electrolyzer, where pressure was rise up to 180bar. It was studied the case of single bubbles behavior, focusing on the typical diameters and rise velocities of hydrogen and oxygen bubbles. The obtained results were compared with a bubbles swarm behavior, where clear differences were observed. To achieve the single bubble generation, a new electrode was design and an electrical pulsed signals was applied as power supply."
Estudio prospectivo de la generación de empleo, valor agregado y reducción de emisiones por despliegue de la energía solar PV distribuida en Argentina 2030
(2017) Suárez, Franco Antonio; Pedace, Roque
"En el presente trabajo se lleva a cabo una prospección cuantitativa de la generación de empleo, valor agregado y reducción de emisiones de gases de efecto invernadero que potencialmente se podría alcanzar por el despliegue de energía solar fotovoltaica distribuida en Argentina en el mediano plazo. Se toma como objeto de estudio las instalaciones en baja y media tensión (220 V – 33 kV) y de 0 – 10 MW, situadas en zonas urbanas o peri-urbanas. Se considera que los tres indicadores simulados son de interés crítico para el soporte a la toma de decisiones a corto, mediano y largo plazo en el ámbito nacional, de cara a una situación de pobreza energética estructural y el compromiso asumido contra el Cambio Climático en París 2015. Bajo este panorama, disponer de información cuantitativa sobre el futuro es esencial."
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."
Thermohydraulic investigation on the use of carbon dioxide as coolant for a solid breeding blanket for DEMO
(2017) Caspari, Felix; Boccaccini, Lorenzo V.; Hernández González, Francisco A.; Smoglie, Cecilia
"The Helium Cooled Pebble Bed (HCPB) Breeding Blanket (BB) is one of the 4 BB concepts being investigated in the EU for their possible implementation in a demonstration nuclear fusion reactor (DEMO). The choice of He as fuid coolant for the BB is motivated by a virtually complete transparency to neutrons, leaving unafected the T production capabilities of the blanket, as well as chemical inertness, molecular stability under high temperatures and neutron irradiation and a superior heat conductivity and capacity, leading to the best cooling performance in terms of heat transfer capabilities among other gas cooling choices. However, this cooling performance figure is hindered by the very low density of the gas, which leads to large pressure drops and high pumping power, thus afecting the overall plant efficiency, as well as to chronic leakages and large coolant inventories. These disadvantages, together with the still immature technology readiness of the respective turbomachinery, the price of this coolant, as well as its recognized limited resources pose concerns about the use of He as coolant for a BB in DEMO. On the other side, carbon dioxide has been the fuid coolant choice since the 50's in the nuclear fission industry for gas cooled reactors (MAGNOX, AGR). Despite its lower heat capacity and thermal conductivity (about 22% and 17% of that of helium respectively), its larger density (11 times larger molecular weight for CO2) can lead to an advantageous performance on heat dissipation rate per unit of pumping power. This feature, coupled with its relative transparency to neutrons, the molecular stability at the operating temperatures of the BB and the industrial scale ready turbomachinery makes CO2 an attractive alternative to He. The feasibility of a CO2-cooled breeding blanket is assessed in this work from the point of view of the thermohydraulic performance."
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."
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.
Technological evaluation of printed, large surface thermoelectric generators for waste heat recuperation: design, simulation and optimization
(2017) Franke, Leonard; Hecht, Matthias
"In future, there will be an increasing demand for waste heat recovery systems (WHRS). So far current technologies are not expected to fulfill the requirement expected for a broad deployment. Thermoelectric generators (TEGs) for the direct transformation from heat to electricity represent hereby a promising alternative. Novel printed TEGs based on organic and inorganic materials (OTEGs) will be brought to market maturity soon. The usage of new cost-efficient materials and the targeted automation as well as the scalability of the production process offer a considerable cost reduction compared to conventional TEGs, making this technology interesting for the recovery of large amounts of waste heat. Moreover, the used materials are environmentally compliant. For first time, a WHRS based on a simple plate heat exchanger design equipped with this new generation of TEGs was evaluated from a technological point of view. For this the thermal behavior of the system was simulated using the Simulink modelling environment and at the same time a fluid dynamical examination of the heat exchanger channels was conducted to determine the dissipated energy by the fluids in the heat exchanger using OpenFOAM. To determine the optimal operational conditions of the system the elaborated models where used. The models demonstrated that current generator efficiencies of ZT 0.1 could deliver next to the auxiliary energy also a surplus power of approximately 250 W compared to a heat power transferred of 39.44 kW. For future TEGs with an efficiency of ZT 0.5 an increase to 1.2 kW was determined by the models which is equivalent to a net system efficiency close to 2.5 %. The waste heat was bundled prior in a thermal oil cycle with a temperature of 230 °C while for the cooling cycle water at 15 °C was assumed".
Feasibility study of adsorption solar cooling systems in Argentina
(2017) Nadur, Diego; Sartarelli, Andrés
"This work is a feasibility study of introducing adsorption solar cooling systems in Argentina. After comparison of various solar cooling technologies, adsorption was chosen because of operation simplicity, use of environmentally friendly working fluids, not use of electrical or mechanical energy and possible use of sun or any other thermal source of energy. - The parameters for the dimensioning and calculus of performance of the refrigerator were defined considering one application of main interest for small milk producers in Argentina: the refrigeration of 30 liters of milk during 3 days. The comparison of the proposed prototype with the current systems in the local market showed its potential to compete."
Investigation of an autonomous energy system for the ICELABPATAGONIA II in Karukinka Natural Park, Chile
(2017) Alfonso, María Paula; Wagner, Andreas
"In the ICELABPatagonia project, different laboratories for Karukinka National Park in Chile were designed. The main objective of these laboratories was to provide shelter against the area’s tough weather conditions, specifically intended for small groups of researchers. The goal behind this design was ensuring environmental preservation as a priority. In order to achieve this, the buildings were required to not produce waste during the construction stages and as well as post construction. In a second stage (the project ICELAB II), a design between five possible candidates was selected and later built. This thesis is meant to provide an in depth review of such design. It has been divided into two stages: The first step consists of taking advantage of natural lighting and reducing energy usage for heating. This was accomplished through the addition of new openings and the installation of insulation materials in walls, roofs, floors and windows. DesignBuilder software was used to simulate the alternate results of installing insulation materials, glazing, air tightness and opening percentages alternatives. As a result, when using fiber glass bats insulation the total heating loss was reduced by 60% from the original design. In addition, electrical demand was reduced by 0.8kWh/day as a result of installing new windows. Natural ventilation was considered as an alternative for cooling the building during summer to avoid overheating. The second step involves the design of an autonomous energy system using photovoltaic cells, consisting of a standalone system which provides the building with electricity without being connected to the grid or requiring a backup system. An 8 module (260kWp) system was selected together with a 4086Ah and 24V battery pack, to supply a 7.26kWh/day demand."
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."
Measurements of velocity fields in a centrifugal fan by means of particle image velocimetry
(2018) Feldle, Christian; Pritz, Balazs; Walter, Johannes
"This thesis contains measurements of flow velocity fields inside the blade channel of a centrifugal fan by using Particle Image Velocimetry (PIV), an optical method for flow vis-ualization. The results are analyzed and compared to previous experiments. It concludes that they show a good compliance and quality. Beforehand, the fan’s characteristic curve and efficiency are determined and validated with preceding investigations. The results show a distinctive conformity with previous experi-ments and a good match with existing simulation data done by the Institute of Fluid Ma-chinery. The measurements are done at different speeds to proof the scalability. The power-train and the mounting for the camera and laser used for the experiments were modified to improve the quality of the data and to simplify the procedure of the PIV experiment. PIV measurements are measured at the points of maximum efficiency, partial load and full load, whose position on the characteristic curve were determined previously. The rotational speed is not varied in the PIV experiment, but in comparison to previous works, where only one fixed plane in the blade channel was measured, multiple planes are measured. This allows to visualize the flow in more depth and a profound knowledge about the flow con-ditions can be gathered."
Experimental investigation of air entrainment by a vertical jet plunging into a liquid pool
(2018) Büttner, Fabian; Schulenberg, Thomas; Gabriel, Stephan; Kuhn, Dietmar
"The aim of the work is the investigation of the liquid flow field that is induced by the jet inside the receiving pool and the simultaneous observation of the gaseous phase. The applied meas-urement techniques were Particle Image Velocimetry (PIV) for analysing the liquid flow field and shadowgraph imaging, which enables a study of the dispersed air bubbles. Furthermore, all boundary conditions that influence the experiment were recorded."
Finite element simulation of a highly water-saturated gas reservoir in northwestern Argentina to forecast its geothermal potential
(2018) Sosa Massaro, Emiliano; Koch, Thomas; Gabi, Martín
"A wide availability of in field Oil & Gas facilities which still have a marginal productive life can be a good opportunity to produce geothermal energy. The challenge is to make good decisions about the company’s assets to include geothermal energy as a candidate in their project portfolio. The self-sustainability of this type of energy production must be ensured by accurate forecasts of the net-energy balance. A geothermal energy production cycle must ensure the best selection of production and injection wells saving energy during their productive lives of the project. A first approach to the simulation of geological faults,lithological heterogeneities of rocks and their interaction with the wells is the basis for the later detailed understanding of the geothermal water cycle. Finite element simulation (FEM) it is a fast tool to understand how the key variables such as ”injection and production flow rates”, ”well-to-well interference” and ”well-to-reservoir heterogeneities interactions” can change the energy consumption needed for geothermal energy production. The role of the key parameters can be easily adjusted to make quick comparisons between different prospects before any detailed engineering is performed. The simulation performed in this thesis has shown a geothermal harvest gain of 58%, when a combination of the more advantageous properties of the geothermal system were used, in comparison with the case represented by the less efficient properties combination.Thanks to the FEM simulation, a detailed interpretation of the peculiarities of production and temperature development shows that not always the more productive case is the most efficient one. The present work presents a method to get a preliminar model of the energy production potential in a water-flooded hydrocarbon reservoir."

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