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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
401

Integrated Solar Technologies with Outdoor Pedestrian Bridge Superstructure Decking

Racz, Richard K 23 March 2016 (has links)
Solar technology has been a major topic in sustainable design for many years. In the last five years, however, the solar technology industry has seen a rapid growth in installations and technological advances in cell design. Combined with a rapidly declining overall system cost, the idea of introducing solar technology into a wider range of applications is becoming a focus for engineers and scientists around the world. So many variables which alter solar energy production, such as the sun and surrounding environment, determine whether a solar design is beneficial. This thesis presents a bridge deck surface integrated with solar cells tested under all AASHTO LRFD pedestrian bridge loadings. A detailed solar analysis of the University of Massachusetts’s campus is presented to determine if solar integration is even plausible for the Northeastern United States with the energy limitations created by the deck integration, as well as an economic evaluation of the deck design. The purpose of this thesis was to determine if a walking surface could be integrated with solar technology and be a plausible alternative to conventional walking surfaces, while providing a source of sustainable power.
402

Modeling and simulation of the effects of cooling photovoltaic panels

Qasim Abumohammad (11819051) 19 December 2021 (has links)
<p>The purpose of this study is to develop a flexible computer tool to predict the power produced by a photovoltaic (PV) panel. The performance of the PV panel is dependent on the incident solar radiation and the cell temperature. The computer tool predicts voltage-current curves, power-voltage curves, and maximum power point values. Five different models are implemented to predict the temperature of the panel, and comparison between the different thermal models is good. A thermal capacitance approach that uses a simple relationship for the forced convection heat transfer coefficient is used to predict the cell temperature. Both the electrical and temperature models are verified through comparisons using PVWatts and validated by comparisons to measured values. The model is flexible in the sense that it can be applied to PV arrays of any size, at any location, and of different cell types. After being verified and validated, the model is used to investigate the effects of cooling on the photovoltaic panel to improve the panel efficiency and increase its power output. Typical results show that for every degree Celsius rise in temperature, the efficiency of the solar panel is reduced by 0.5%. The effect of cooling and the resulting increase in energy production in two different climatic zones are studied and discussed. </p>
403

RESIDENTIAL ELECTRICITY CONSUMPTION ANALYSIS: A CROSSDOMAIN APPROACH TO EVALUATE THE IMPACT OF COVID-19 IN A RESIDENTIAL AREA IN INDIANA

Manuel Eduardo Mar Valencia (11256321) 10 August 2021 (has links)
The pandemic scenario caused by COVID-19 is an event with no precedent. Therefore, it<br>is a phenomenon that can be studied to observe how electricity loads have changed during the stayat-home order weeks. The data collection process was done through online surveys and using<br>publicly available data. This study is focusing on analyzing household energy units such as<br>appliances, HVAC, lighting systems. However, collecting this data is expensive and timeconsuming since dwellings would have to be studied individually. As a solution, previous studies<br>have shown success in characterizing residential electricity using surveys with stochastic models.<br>This characterized electricity consumption data allows the researchers to generate a predictive<br>model, make a regression and understand the data. In that way, the data collection process will not<br>be as costly as installing measuring instruments or smart meters. The input data will be the<br>behavioral characteristics of each participant; meanwhile, the output of the analysis will be the<br>estimated electricity consumption "kWh." After generating the "kWh" target, a sensitivity analysis<br>will be done to observe the electricity consumption through time and examine how people evolved<br>their load during and after the stay-at-home order.<br>This research can help understand the change in electricity consumption of people who<br>worked at home during the pandemic and generate energy indicators and costs such as home office<br>electricity cost kWh/year. In addition to utilities and energy, managers can benefit from having a<br>clear understanding of domestic consumers during emergency scenarios as pandemics. <br>
404

Vyhodnocení nákladů na penalizace v zadané distribuční síti / Evaluation of penalization costs charged in a specific power distribution network

Těžký, Jiří January 2008 (has links)
Energy system is important for classification of flation of developing countries. Function of energy system is supply electric power of high quality for every customers in system. Requirements of quality are different for individual countries. Reliability of electricity sector system is important parameter in every electricity systems. At the present time are the requirements of quality much higher, because of condition of liberalized market. Each country have different systems of standards of classification of reliability. Penalizations are assign to, when the systems of standards are overrun. Type of penalization is different for each countries. In my work I looked on system of electricity sector system, its reliability, operating, and organization etc. In principle for Czech Republic. Basic documents of electric legislation are described in this work, it is described for Czech Republic and for European Union. Public notice No. 540/2005 Sb. is described. This public notice interpret laws about supplies of electricity and others services in electricity sector system in Czech Republic. Penalizations are described in this public notice. Standards of penalizations are different for each European countries. Various monitoring of penalization are used. Also dividing of penalization is different for each country. At the last part of my work I analyze costs of penalization in required distribution network. Most reason of failure cause are analyzed here. Size of costs of penalization are compared in this part of my work, for changes of standards in required distribution networks. Required countries are Czech Republic, Great Britain and Spain. These countries are compare with each other. I evaluate the worst outlets of required distribution network. The worst outlets are outlets with higher costs of penalizations. These worst outlet I compare for required countries and between each other. At the end of my work I analyze failure causes for the worst outlets in penalization system of Czech Republic.
405

Obnova napětí v oblasti Prostějova a Zlína / The voltage restoration in Prostějov and Zlín distribution area

Wasserbauer, Vojtěch January 2013 (has links)
The aim of this thesis is description of critical situations in the electrical grid and the consequences which can be caused by these situations. Further possibilities of voltage recovery and ways how to reach the needed voltage are described. Another part is firstly about regulation electrical system and resources which are connected to this system. Secondly there is appraisal of possibility of connection new resource into distribution system 110 kV and conditions of connection new resources. The result of the thesis is description voltage recovery and the rules which have to be kept during critical situations.
406

EXPERIMENT AND MODELING OF COPPER INDIUM GALLIUM DISELENIDE (CIGS) SOLAR CELL: EFFECT OF AXIAL LOADING AND ROLLING

Arturo Garcia (8848484) 15 May 2020 (has links)
<div>In this paper various applications of axial tensile load, bending load, and rolling loading has been applied to a Copper Indium Gallium Diselenide (CIGS) Solar Cell to lean how it would affect the solar cell parameters of: Open circuit voltage (Voc), Short circuit current, (Isc), Maximum power (Pmax), and Efficiency (EFF), and Fill Factor (FF). These Relationships were found for with three different experiments. The first experiment the applies axial tensile stress is to a CIGS solar cell ranging from 0 to 200 psi with various strain rates: 0.0001, 0.001, 0.01, and 0.1 in/sec as well as various relaxation time: 1min, 5min, and 10 min while the performance of solar cell is measured. The results of this gave several trends couple pertaining the Voc . The first is that open circuit voltage increases slightly with increasing stress. The second is the rate of increase (the slope) increases with longer relaxation times. The second set of trend pertains to the Isc. The first is that short circuit current generally is larger with larger stress. The second is there seems to be a general increase in the Isc up to a given threshold of stress. After that threshold the Isc seems to decrease. The threshold stress varies depending on strain rate and relaxation time. The second set of experiments consisted of holding a CIGS solar cell in a fixed curved position while it was in operational use. The radii of the curved cells were: 0.41, 0.20, 0.16, 0.13, 0.11, 0.094, and 0.082 m. The radii were performed for both concave and convex cell curvature. The trends for this show a slight decrease in all cell parameters with decreasing radii, the exception being Voc which is not effecting, the convex curvature causing a slightly faster decrease than the concave. This set of experiments were also processed to find the trends of the single diode model parameters of series resistance (Rs), shunt resistance (Rsh), dark current (I0), and saturation current (IL), which agreed with the experimental results. The second experiment consisted of rolling a CIGS solar cell in tensile (cells towards dowel.) and compression (cells away from dowel) around a dowel to create internal damage. The diameter of the dowels decreased. The dowel diameters were: 2. 1.75, 1.25, 1, 0.75, 0.5, and 0.25 inches. This experiment showed similar trends as the bending one but also had a critical diameter of 1.75 in where beyond that damage much greater. Finally a parametric study was done in COMSOL Multiphysics® to examine how changes in the CIGS material properties of electron mobility (EM), electron life time, (EL), hole mobility 15 (HM), and Hole life time (HL) effect the cell parameters. The trends are of an exponential manner that converges to a given value as the material properties increase. When EL, EM, HL are very small, on the order of 10-4 times smaller than their accepted values, a transient like responses occurs.<br></div>
407

Geothermienutzung in sächsischen Gartenbaubetrieben

Richter, Marcus, Huber, Christian, Reinhardt, Katrin, Wachmann, Hendrik, Gerschel, Axel 21 May 2015 (has links)
Die Broschüre beschreibt Möglichkeiten der Wärmeversorgung von sächsischen Gartenbaubetrieben mit Geothermie in Abhängigkeit von geologischen Standortfaktoren und Betriebsstrukturen/ Nutzungskonzepten. Ziel des Projektes war, für die Beheizung von Gewächshäusern den Einsatz von Geothermie zur Grundlastversorgung zu untersuchen. Hervorzuheben ist hierbei die Verknüpfung der geologischen/geothermisch und gärtnereitechnischen Komponente. Die Ergebnisse zeigen, welches geothermische System die wirtschaftlichste Variante für Gewächshäuser und deren Nutzung ist. Das Projekt stellt eine Entscheidungsgrundlage für die Nutzung von Geothermie in sächsischen Gartenbaubetrieben dar.
408

Německo jako "rozpolcený aktér" na příkladu projektu Nord Stream / Germany as "dividual actor" on the case of Nord Stream project

Bundová, Klára January 2019 (has links)
This Master thesis examines the German foreign energy policy with focus on the German- Russian energy cooperation and the pipeline projects Nord Stream I and II. It seeks to analyze inconsistencies or even contradictions in the German foreign policy regarding the Nord Stream project. Both strategic and business interests on one hand and value based policy on the other are present and observable. Therefore this paper works with Jakub Eberle's concept of Germany as "dividual actor" which enables us to work with the already mentioned inconsistencies. Furthermore, this approach allows us to observe "geo-economic power" aspects in German actions (favoring strategic and mostly business interests) as well as "civilian power" aspects (value based policy) and eventually to see Germany as an actor in the international relations in its complexity. This thesis therefore aims to contribute to a broader debate about German actorness and its roles in international system. Moreover, German domestic energy policy will be analyzed in order to provide us with the basis for German foreign energy policy. The main focus of this paper is on natural gas and its importance in the German energy mix as well as on German dependence on its imports. The import routes and primarily the pipeline routes Nord Stream I and II are...
409

EVALUATIONS ON ENZYMATIC EPOXIDATION, EFFICIENCY AND DECAY

Elena A Robles Molina (9751112) 14 December 2020 (has links)
<p>The potential use of enzymes in industrial synthesis of epoxidized soybean oil has been limited through the high cost of the enzyme catalyst, in this work we evaluate the effectiveness of chemo enzymatic epoxidation of high oleic soybean oil (HOSBO) using lipase B from <i>Candida antarctica </i>(CALB) on immobilization support Immobead 150 and H<sub>2</sub>O<sub>2 </sub>in a solvent-free system. Additionally, we evaluated the production decay rates for hydrolytic activity and epoxide product formation over consecutive batches to determine half-life of the enzyme catalyst. </p> <p> Batch epoxidation of HOSBO using CALB on 4wt% loading shows yields higher than 90% after 12 hrs. of reaction, and with a correlation to the consumption of double bonds suggesting that the reaction is selective and limiting side product reactions. Non-selective hydrolysis of oil was not found beyond the initial hydrolysis degree of raw HOSBO. Evaluations of decay given by epoxide product formation and released free fatty acids shows a half-life of the enzyme catalyst on these activities is of 22 ad 25 hrs. respectively. Finally, we evaluated the physical parameters influencing this decay, and found that H<sub>2</sub>O<sub>2</sub> presence is the most important parameter of enzyme inactivation with no significant effect from its slowed addition. We propose a new reactor configuration for the analysis of the specific steps on epoxide formation through peracid intermediates. </p>
410

Energiemanagement Strategien für elektrische Energiebordnetze in Kraftfahrzeugen

Büchner, Stefan 10 July 2008 (has links)
Die elektrische Energieform gewinnt im Kraftfahrzeug wegen ihrer Nutzungsvielfalt und sehr guten Steuerbarkeit für die Realisierung neuartiger Funktionen zunehmend an Bedeutung. Voraussetzung für ihren Einsatz ist eine zuverlässige und effiziente Bereitstellung durch das Kfz-Energiebordnetz. Dafür ist ein intelligentes Energiemanagement erforderlich, welches mit geeigneten Strategien die Leistungsflüsse im Energiesystem koordiniert. In dieser Arbeit werden die beiden Entwurfsziele der Zuverlässigkeit und der Effizienz bei der Entwicklung von elektrischen Energiemanagement-Strategien systematisch betrachtet. Es erfolgt eine Beschreibung und Zuordnung der einzelnen Ziele und Maßnahmen anhand der Energieflüsse und Wirkungsketten. Ein Schwerpunkt bildet dabei die Beherrschung von Lastwechseln im Bordnetz. Für Aussagen hinsichtlich einer effizienten Erzeugung elektrischer Energie erfolgt eine Untersuchung der Energiewandlungskette anhand analytischer Methoden und mit Hilfe einer simulationsgestützten Optimierung. Ein weiterer Fokus der Arbeit liegt in der Betrachtung zur Anwendung ökonomischer Modelle für eine Energiekoordination. Es werden die theoretischen Grundlagen der Mikroökonomie zusammengestellt und mögliche Funktionsstrukturen eines einseitigen und zweiseitigen Allokationsmechanismus verglichen und bewertet. Abschließend zeigen experimentelle Untersuchungen an einem Bordnetzprüfstand zum Lastwechselverhalten und die Integration eines Energiemanagement-Systems den praktischen Bezug zum realen System.

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