Στη συγκεκριμένη διπλωματική εργασία μελετάται η δομή και η λειτουργία φωτοβολταϊκών πλαισίων πολυκρυσταλλικού πυριτίου. Για το σκοπό αυτό είναι απαραίτητη τόσο η θεωρητική μελέτη και περιγραφή της λειτουργίας τους, όσο και η πειραματική προσέγγιση του θέματος. Αρχικά, παρουσιάζεται η δομή των ηλιακών κυττάρων, βασικών δομικών μονάδων των φωτοβολταϊκών πλαισίων. Στην αρχή δίνεται μια περιεκτική περιγραφή της λειτουργίας της p-n επαφής ώστε στη συνέχεια να γίνει ευκολότερα κατανοητός ο τρόπος που επιδρά το φωτοβολταϊκό φαινόμενο στη δομή αυτή. Αναλύονται ορισμένα μεγέθη που χρησιμοποιούνται στην επιστήμη των φωτοβολταϊκών καθώς και οι συνθήκες στις οποίες μετρώνται παγκοσμίως τα ηλιακά κύτταρα/πλαίσια προκειμένου να υπάρχει ένα κοινό μέτρο σύγκρισης. Η μελέτη ολοκληρώνεται με την πειραματική διαδικασία. Σε αυτήν αναλύονται διεξοδικά οι παράγοντες που επηρεάζουν τη λειτουργία των φωτοβολταϊκών σε μια πραγματική εγκατάσταση. Οι παράγοντες αυτοί είναι κυρίως περιβαλλοντικοί (ηλιοφάνεια, θερμοκρασία). Υπάρχουν εξίσου σημαντικοί παράγοντες, όμως, που είναι δυνατό να μεταβληθούν από τον άνθρωπο με τρόπο ώστε να επιτευχθεί η βέλτιστη απόδοση. Πιο συγκεκριμένα, η γωνία κλίσης του πλαισίου και η περίπτωση της σκίασής του είναι απαραίτητο να ληφθούν σοβαρά υπόψη. Τα συμπεράσματα που προέκυψαν έχουν άμεση εφαρμογή στον υπολογισμό και τη μελέτη μιας πραγματικής εγκατάστασης μιας και δίνουν συγκεκριμένες αριθμητικές τιμές. Για παράδειγμα η συνολική αποδιδόμενη ετήσια ενέργεια από ένα πλαίσιο 80Wp τοποθετημένο με γωνία κλίσης ίση με τη βέλτιστη (380) στην περιοχή της Πάτρας είναι 172.038kWh. Αξιοσημείωτη είναι και η σύγκριση των πειραματικών τιμών ισχύος και συντελεστή απόδοσης με τις τιμές του κατασκευαστή και αυτές που προέκυψαν μέσω μοντελοποίησης (σε υπολογιστή με τα προγράμματα Matlab και Mathematica). Αυτές είναι: η μετρούμενη ισχύς του πλαισίου 73,15Watt και συντελεστής απόδοσης η=11,5%, ισχύς διδόμενη από τον κατασκευαστή 81,71Watt με συντελεστή απόδοσης η=12,6% και ισχύς η που προκύπτει από τη μοντελοποίηση 89,95Watt με συντελεστή απόδοσης η=14,2%. Η αιτιολόγηση αυτών των διαφορετικών τιμών ισχύος και των αντιστοίχων συντελεστών απόδοσης αποδίδεται στην αδυναμία να πετύχουμε ίδιες συνθήκες διεξαγωγής αυτών των μετρήσεων καθώς και στην σε σειρά και παράλληλη αντίσταση που δεν είναι δυνατόν να εκτιμηθούν ακριβώς για να εισαχθούν στο μοντέλο. / This thesis studies the structure and performance of polycrystalline silicon solar modules. To do this, not only a theoretical study of their operation is necessary, but also an experimental approach of the subject. In a first step, we can see the structure of polycrystalline silicon solar cells, which compose the solar panels. It was thought useful to give a compact description of the –p-n junction function. This way, the photovoltaic phenomenon’s impact on –p-n junction’s function can be easier understood. Along with the theoretical part, there is an analysis of some values that are used to the photovoltaic science along with the conditions that are used in order to have a common meter of comparison. A study, however, would not be completed if the experimental process did not exist. In this process the factors that influence the photovoltaic operation are analyzed at great length in a real installation. These factors are mainly environmental (sunlight, temperature). There are equally important factors, however, which are possible to be altered in such a way to achieve the most optimal performance. Specifically, the tilt angle and the shading case of the solar module are essential to be taken seriously into consideration. The results can be directly used for the calculation of a real installation and are very helpful as they are quite specific. For example, the total output power with a tilt angle of 380 at Patras-Greece is 172.038kWh. It is also remarkable to have a comparison between the experimental data, the data given by the constructor and the data gathered through simulation method. The values for the output power are 73,15Watt (η=11,5%), 81,71Watt (η=12,6%) and 89,95Watt (η=14,2%) respectively. The explanation of different power factor and output power comes from the inability to achieve exactly the same experimental conditions. Moreover, the shunt and series resistances cannot be calculated exactly due to lack of constructor’s data details.

Η παρούσα διπλωματική εργασία πραγματεύεται τη μελέτη, προσομοίωση και κατασκευή διάταξης για τη διασύνδεση ενός φωτοβολταϊκού πλαισίου με το δίκτυο χαμηλής τάσης. Η διάταξη που επιλέχθηκε αποτελεί την πρώτη βαθμίδα, σε ένα σύστημα που χρησιμοποιεί μετατροπέα δύο βαθμίδων, αναλαμβάνοντας την ανύψωση της τάσης του φωτοβολταϊκού πλαισίου. Αρχικά μελετήσαμε τους πολλαπλασιαστές τάσης Half-Wave Cockcroft-Walton, Dickson και Half-Wave Cockcroft-Walton με Πυκνωτή Εξομάλυνσης κάνοντας μια σειρά προσομοιώσεων. Στη συνέχεια, προχωρήσαμε στην κατασκευή του Half-Wave Cockcroft-Walton και ενός αντιστροφέα συντονισμού πλήρους γέφυρας ως βοηθητικό κύκλωμα για να είναι εφικτή η διασύνδεση του Half-Wave Cockcroft-Walton με το φωτοβολταϊκό πλαίσιο. Τέλος, έγινε παράθεση και σχολιασμός των πειραματικών αποτελεσμάτων που προέκυψαν μετά την ολοκλήρωση της κατασκευής. / This diploma thesis deals with the study, simulation and construction of a grid connected converter which connects a photovoltaic panel into the electric grid. To be more specific, there are three voltage multipliers that have been analyzed and simulated, Half-Wave Cockcroft-Walton, Dickson and Half-Wave Cockcroft-Walton with Levelling Capacitor. The final step of this work deals with the construction of Half-Wave Cockcroft-Walton converter and the valuation of the experimental results

Orientador: Rosana Maria Caram / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-12T10:08:15Z (GMT). No. of bitstreams: 1 Barata_TomasQueirozFerreira_D.pdf: 15029001 bytes, checksum: 04d10e9f85d3f80e13a7bceb02b3cbaa (MD5) Previous issue date: 2008 / Resumo: Esta pesquisa representa uma contribuição aos processos e as técnicas de projeto e produção de componentes de vedação pré-fabricados em madeira, com ênfase na identificação das propriedades térmicas e na indicação de uso, considerando os diferentes climas brasileiros. Neste sentido, seu objetivo principal é propor projetos, produzir protótipos em escala real e verificar a adequação de painéis leves de vedação externa às zonas bioclimáticas brasileiras, segundo a norma NBR 15220. A metodologia dividiu-se em três etapas principais: na primeira, caracterizam-se cinco tipologias de painéis de vedação em madeira, determinam-se as suas propriedades térmicas e investiga-se a influência da espessura da parede, do volume de madeira, da câmara de ar não ventilada e da cor da superfície externa em relação às propriedades térmicas de painéis de madeira; na segunda, apresentam-se as etapas de desenvolvimento do projeto executivo e da produção de três propostas de painéis de vedação com emprego de madeira de reflorestamento serrada de pequeno comprimento (= 2,50m), madeira roliça de baixo diâmetro (= 0,15m), placas OSB (Oriented Strand Board) e placas de materiais reciclados; na terceira etapa abordam-se a determinação das propriedades térmicas e a adequação às zonas bioclimáticas brasileiras das propostas desenvolvidas. Os primeiros resultados são a síntese das características dos projetos e dos processos produtivos e a verificação de adequação ao zoneamento bioclimático de cinco tipologias de painéis de vedação em madeira. Os resultados finais apresentam o projeto executivo, as etapas de produção, a determinação das propriedades térmicas e a verificação de adequação ao zoneamento bioclimático, segundo a norma NBR 15220-3. / Abstract: This research is a contribution to the design and production techniques and processes of pre-fabricated wooden lining components, with emphasis on their thermal properties and use, considering the different Brazilian climates. In this regard, the main goal is to propose projects, produce real prototypes and verify the suitability of external lightweight lining panels for the Brazilian bioclimatic zones, according to the standard NBR 15,220. The methodology was divided into three main stages: the first characterizes the five types of wooden panels, determines its thermal properties and studies the influence of the wall thickness, the volume of wood, the unventilated air chamber and the color of the external surface with relation to the wooden panels' thermal properties; the second stage, demonstrates the developing steps for the executive project and the production of three proposals for lining panels using small-diameter sawed reforestation wood (= 2.50 m), low-diameter round wood (= 0.15 m), OSB boards (Oriented Strand Board) and boards of recycled materials; the third step determines the thermal properties and suitability for the Brazilian bioclimatic areas of the developed proposals. The first results summarize the characteristics of the projects and production processes and verification of the bioclimatic zoning suitability of five types of wooden lining panels. The final results exhibit the executive project, production stages, determination of the thermal properties and verification of the bioclimatic zoning suitability, according to standard NBR 15220-3. / Doutorado / Arquitetura e Construção / Doutor em Engenharia Civil

No description available.

Les concentrateurs photovoltaïques sont parmi les technologies d'énergies solaires les plus prometteuses. Ils ont une efficacité allant jusqu'à deux fois celle des panneaux photovoltaïques conventionnels. Malgré les avancements en recherche et développement, les concentrateurs photovoltaïques demeurent des systèmes relativement complexes. Cette même complexité laisse place à l'innovation et à la possibilité de réduire considérablement les coûts de fabrication. Dans le cadre de cette thèse, deux sites de tests sont développés et déployés pour faire l'analyse des performances des concentrateurs photovoltaïques plats. Quatre designs de cellules solaires sont caractérisés en laboratoire et incorporés dans les panneaux prototypes pour ensuite être individuellement étudiés. Les quatre designs sont ensuite comparés l'un à l'autre, et selon leurs emplacements, pour comprendre comment le design de la cellule affecte la performance des panneaux.

No description available.

Sandwich panels serve many purposes in engineering applications. Additive manufacturing opened the door for easy fabrication of the sandwich panels with different core structures. In this study, additive manufacturing technique, experiments, and numerical analysis are combined to evaluate the mechanical properties of sandwich panels with different cellular core structures. The sandwich panels having honeycomb, re-entrant honeycomb, diamond, square core topologies are printed with the vat photopolymerization technique. Uniaxial compression testing is performed to determine the compressive modulus, strength, and specific strength of these lightweight panels. Elasto-plastic finite element analysis having good similarities with the experimental results provided a preview of the stress distribution of the sandwich panels under applied loading. The imaging of the tested samples showed the fractured regions of the cellular cores. Dynamic mechanical analysis of the panels provided scope to compare the performance of panels and solid materials with the variation of temperature. Sandwich panels with the diamond structure exhibit better compressive properties and specific strength while the re-entrant structure offers high energy absorption capacity. The sandwich structures provided better thermo-mechanical properties than the solid material. The findings of this study offer insights into the mechanical properties of sandwich panels printed with vat photopolymerization technique which can benefit a wide range of engineering applications.

This work deals with modernization of information LED panels. It mainly focuses on utilizing input HDMI interface into FPGA, which controls modular LED displays, but also on ensuring professional functions such as communication with control unit, thermal security and detection of faulty LED.

Thesis (M.F.A.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / This publication is the discussion and examination of work produced for the degree of Masters of Fine Arts in enameling and metal work. The body of work created consists of enameled brooches and wall panels. The thesis paper documents the technical and aesthetic developments in painting and metals as they pertain to the thesis work, and discusses the landscape subjects which so strongly influence the images that I create. The work produced for the thesis show is discussed in the manner in which it was conceived, as groupings; or as series. Methods of manipulating enamels for specific visual and textural results, various enamel finishes, and the use of enamel oxides are documented. Metal techniques employed as well as the framing method devised for the presentation of the wall panels are also documented. References and key incluences are painters and artists working in metalsmithing and jewelry. In the painting field Narcisse Diaz, Charles-Francois Daubigny, Eduard Vuillard and George Inness are nineteenth century artists who greatly influenced my artistic development. In the metals field Charles Loloma, Georg Jensen and Rene Lalique are influences which established the foundations of my ideas and tastes in my jewelry . While at graduate school the work and teachings of enamelists Jamie Bennett and William Hellwig initiated the interests I developed for enameling. The paper is essentially an indepth analysis of the way in which I perceive my work, what I want to communicate to the viewer, and how and why I create the kinds of objects that I do. / 2031-01-01

This thesis work is a continuation of a project aimed at the consolidation of insulation material (IM) to produce porous ceramics with sufficient porosity and compression strength for post-insulation of buildings. The porous structure and contact points are tailored to produce IM with ultra-low thermal conductivity.  One of the main goals is to introduce expandable microspheres, that are perfect lightweight fillers and blowing agents into production. They are relatively new materials in the market which are used to manufacture products with low weight and controlled foam structure. Therefore, it is of interest to be integrated into the construction field as a component for insulating materials.  The project is built on the advanced structuring of porous materials with tailored porosity to offer 5-10 times lower thermal conductivity value providing adequate insulation with an insulation cover of 2-10 mm in thickness. Enhancing the insulating capacity allows to limit the use of energy to improve energy efficiency. Thus, less energy is required to heat or cool the indoor climate. The success in achieving such thin effective IM will eliminate the need for any modification of existing window frames, electrical and heating installations. In the first stage, it is necessary to confirm the entire concept of creating a thermal IM with a controlled porous structure using various compositions of materials and an assessment of the structure, porosity, and functional properties. This project focuses on developing a composition of ceramic panels. The various components of the ceramic panels including the type of ceramic are adjusted and their effects on the composition are described. Pure alumina, activated alumina and silica have been investigated to find the optimized quality and price. In addition, various methods and conditions have been implemented for panel fabrication.  Prototypes of ceramic panels are prepared for demonstration, followed by upscaling at the facilities of industrial partners. The project has been performed in collaboration with companies i.e., Nouryon, HIPOR Materials AB, and LindePac AB as the industrial partner.