The following Master Thesis will talk about a C-PV prototype using bifacial PV technology, based on the Solarus Collector. The Solarus Collector consists in two PV cells built on a metallic receiver, where there are some water channels flowing through it, allowing to cool down the PV cells, thus increasing their efficiency. The collector also presents a reflector to provide irradiance to the back part of the receiver, where the other PV cells are located. The new prototype will present bifacial PV cells but not a metallic receiver. This construction aims to reduce the price of the receiver, but will not have a system to cool down the solar cells. This Master Thesis will be developed in the Solarus facilities, in collaboration with the Solarus members. In order to grasp an idea of this prototype, two main procedures will be done. Regarding the bifacial technology, a bifacial PV module will be measured under different conditions, depending on which sides can be illuminated or shaded. On the other hand, a thermodynamic simulation will be carried out on different geometries of the reflector and receiver, in order to figure out the evolution of the temperatures on the new prototype. This simulation will be done with a finite element method, widely known in this applications. The results will show several problems concerning this prototype. Although the measurements of the bifacial PV module will result beneficial and informative, the problem with the temperature will tend to back down this prototype. The lack of some system to cool down the bifacial cells will imply that the receiver could reach unacceptable temperatures. This hypothesis will be drawn under some specific conditions, so they will not be completely devastating to the idea of using bifacial cells, but perhaps a different approach should be used in case it is desired to continue this work.

[pt] O Estudo das condições de trabalho dos catadores de materiais recicláveis do polo de Jardim Gramacho: uma análise com base em aspectos ergonômicos busca analisar as condições de trabalho dos catadores integrantes do polo de Jardim Gramacho no que diz respeito aos aspectos ergonômicos e os impactos do trabalho desempenhado na saúde laboral e pessoal, pois mesmo com a evolução dos requisitos legais, após décadas de aprimoramento das leis trabalhistas, ainda nos deparamos com questões adversas ao que determina a legislação. Neste contexto, a pesquisa teve como objetivo principal identificar os principais problemas que acarretam danos à saúde destes profissionais estigmatizados pela natureza de sua atividade e vitimados pela precarização de políticas públicas eficazes voltadas para a saúde do trabalhador informal. Para fundamentar o estudo, foi realizado levantamento bibliográfico e pesquisa de campo, além das técnicas de observação participante e escuta dos sujeitos por entrevistas semiestruturadas, com vistas a compreender o processo atual de trabalho, analisando pontos em que houvesse prejuízo à saúde do trabalhador. A análise foi conduzida por meio de ferramentas e métodos ergonômicos, os quais possuem fundamentação na legislação de saúde e segurança ocupacional. O estudo realizado situou-se na Cooperativa Mais Verde, a maior dentre as instaladas no Polo. Pela amostra de trabalhadores pesquisada foi possível comprovar um ambiente carente de medidas que contribuam com a saúde laboral. Enfim, são propostas algumas medidas para a reversão deste cenário, a fim de possibilitar mais qualidade de vida a estes sujeitos importantes na gestão de resíduos sólidos brasileira. / [en] The environmental issue and human welfare have become an increasingly challenging goal for today s society, as the scarcity of natural resources has overcharged the rulers as they search for renewable energy and consumption alternatives. Great reflections related of the life quality in Brazil have appeared in relation to welfare, especially in the case of the poor classes, such as recyclable waste collectors, who often face a subhuman working hour striving to obtain the basic survival conditions, leaving the comfort and welfare in their lives behind them. These factors were the motivation by the choice of this line of study — especially because the researcher is graduated in production and safety engineering, acting on issues related to labour wellfare in order to provide work environments that allow the execution of professional activities in harmony with the physical and psychological wellfare of workers. I m currently an employee of the multinational General Electric, a private institution that has different business segments on a global scale. I work in the aviation industry and I have the experience of working in an environment that aims, firstly, at the welfare of your employees — a factor that undoubtedly gave me even more background, theoretical and practical knowledge, as well as technical capacity to act in the present work. This study is not part of a joint initiative of the company mentioned above with this author; it is only an individualized academic study, conducted with the advice and guidance of a thesis supervisor, as a requirement for obtaining a master s degree in Urban and Environmental Engineering by PUC-Rio.

This work addresses the design and real-time implementation of adaptive control strategies on the parabolic solar collector to enhance the production efficiency under varying working conditions. For example, the unpredictable variations of the solar irradiance and thermal losses, these factors can be a major problem in the control design. The control objective is to force the outlet temperature of the collector fluid, to track a predefined reference temperature regardless of the environmental changes. In this work, two control strategies have been designed and analyzed. First, an intelligent proportional-integral feedback control, which combines the proportionalintegral feedback control with an ultra-local model is proposed. This strategy uses a transfer function model that has been derived and identified from real-time data and used to test the controller performance. Second, an adaptive nonlinear control using Lyapunov stability theory combined with the phenomenological representation of the system is introduced. This strategy uses a bilinear model derived from the heat transfer equation. Both control strategies showed good performance in the simulations with respect to the convergence time and tracking accuracy. Besides, the conventional proportional-integral controller has been successfully implemented in the real system.

2015 the Paris agreement was signed to tackle the climate change and reduce emissions from fossil fuel burning. The industrial and manufacturing sector which alone accounts for 32% of global energy use relies heavily on fossil fuels. Solar thermal energy is a renewable energy source that has potential of replacing large portions of this energy. The Swedish research and development company, Absolicon Solar Collectors AB are manufacturers of solar collectors and production lines of dito. Their main product, the Absolicon T160, is a concentrating solar collector which can produce heat up to 160°C.India, and more specifically the state of Gujarat is an interesting market for the solar collectors. This study is aiming to give Absolicon a better understanding of the potential of replacing fossil fuel with solar thermalenergy in Gujarat, so that they can direct their efforts in the right direction. It is a qualitative study mainly focused on the dairy and textile processing industry, two important sectors in the state that has process demands which can be run on solar thermal energy. Since no reliable data regarding the energy consumption in the studied industries where found, a method for estimating the energy consumption is presented in the study.The results from the study shows that large scale manufacturing is possible from a demand point of view, but there are many hindrances for a market penetration. In India large portions of the industry segments studied is non-organized, i.e. small scale with low level of modern technology. Integration of solar thermal energy in the non-organized sector demands a different approach. Based on the results a market analysis with suggestions on how to proceed for the different industrial segments studied is presented.Despite good solar insolation in the state the solar resource was studied in greater detail as aerosols and dust can affect the energy yield from the solar collectors. The results indicates that the annual solar irradiation can be both over- and underestimated when using satellite derived models. India has monsoon seasons and seasonal winds which affects the levels of aerosols in the atmosphere. The level of aerosols and dust has ahigh impact on the solar resource.Ground measurements are therefore a complement that could be used to get a better understandingon site.

Problems of heating of supply water by solar energy are described in this paper. In term of these works was designed and realized attenuate prototype of solar system. There was realized measurements of the temperatures on this prototype and on the basis of these measurements was identified system parameters. Creation of compute simulation of solar system was the further step of this paper. The compute simulation was verified on the basis of comparing of final temperatures with experimental prototype. The design of control algorithm of flow of liquid through the solar system to reach the maximum effect of system is programme of this paper. Simulations of control algorithms are make in environment of MATLAB SIMULINK.

Direct absorption solar collectors offer possible improvement in efficiency over traditional surface absorbing collectors, because they have fewer heat transfer steps and has the ability to utilise higher radiation fluxes. Carbon black based nanofluids, in a base fluid of salt water, were synthesised by a two-step method where the carbon black nanoparticles were treated with a surfactant, TWEEN-20, in a 1:2 mass ratio and sonicated for 60 minutes to break up agglomerates. The synthesised nanofluids showed stability for over 31 days. The different carbon black concentration nanofluids' solar irradiation absorption properties were compared with each other and with the base fluid of salt water in a concentrating, as well as non-concentration scenario. It was found that the carbon black nanofluids showed excellent absorption properties over the entire solar radiation spectrum. A 1 m2 concentrating unit using a two-axis tracking system, with two mirrors and a 1 m diameter circular Fresnel lens, was used to concentrate solar radiation on a direct absorption solar collector flow cell with a 10 cm2 collection area. An optimum concentration of 0.001 volume % carbon black was found to show a 42 % increase in heating rate, compared to that of salt water. The collector was, however, hampered by high energy losses and the maximum collector efficiency achieved was only 46 %, 23 % higher than that of salt water. The overall system efficiency was only 22 %. This low efficiency can be attributed to the high optical concentration losses (50 % - 70 %) present in the concentrating unit. / Dissertation (MEng)--University of Pretoria, 2016. / Chemical Engineering / MEng / Unrestricted

Oberflächennahe Erdwärmekollektoren, insbesondere horizontale Erdwärmekollektoren, stellen eine wirtschaftlich und energetisch sinnvolle Wärmequellenanlage für Wärmepumpen dar. Auf Grund mangelnder wissenschaftlicher Untersuchungen in der Vergangenheit wurde deren Leistungsfähigkeit bisher jedoch kaum ausgenutzt. Des Weiteren fühlten sich die Planer bei der Auslegung oft unsicher, da es kaum verlässliche Auslegungsrichtlinien gab. In dieser Arbeit werden ein numerisches und ein analytisches Rechenmodell vorgestellt, mit denen Jahresverläufe der charakteristischen Soletemperaturen und der Eisbildung realitätsnah simuliert werden können. Mit Hilfe dieser Rechenmodelle wurde unter Berücksichtigung unterschiedlicher Bodentypen und Klimazonen die hydraulische und geometrische Auslegung anhand der Kriterien Energieeffizienz, Wirtschaftlichkeit, Betriebssicherheit und Umweltbeeinflussung bewertet, optimiert und Einsatzgrenzen klar ausgearbeitet. Daneben wurde auch die Auslegung für Kollektoren bei Spitzenlastnutzung und Sonderbauformen wie Grabenkollektoren und Erdwärmekörben untersucht.

Particulate contamination of the optical surfaces of solar collectors, often called "soiling", can have a significant deteriorating impact on energy yield due to the absorption and scattering of incident light. Soiling has more destructive effect on concentrated solar systems than on flat-plate photovoltaic panels, as the former are incapable of converting scattered sunlight. The first part of this thesis deals with the soiling losses of flat-plate photovoltaic (PV), concentrated solar power (CSP), and concentrated photovoltaic (CPV) systems in operation in several regions of the world. Influential parameters in dust accumulation losses, as well as different cleaning mechanisms in pursuit of restoring the efficiency of soiled systems, have been thoroughly investigated. In lieu of the most commonly-practiced manual cleaning method of using high-pressure water jets, the concept of automatic dust removal using the electrostatic forces of electrodynamic screen (EDS) technology is in a developmental stage and on its way toward commercialization. This thesis provides comprehensive analytical solutions for the electric potential and electric field distribution in EDS devices having different configurations. Numerical simulations developed using finite element analysis (FEA) software have corroborated the analytical solutions which can easily be embedded into software programs for particle trajectory simulations while also providing flexibility and generality in the study on the effect of different parameters of the EDS on the electric field and ensuing dust-removal performance. Evaluation and comparison of different repelling and attracting forces exerted on dust particles is of utmost importance to a detailed analysis of EDS performance in dust removal. Hence, the balance of electrostatic and adhesion forces, including van der Waals and capillary forces, have received significant attention in this dissertation. Furthermore, different numerical analyses have been conducted to investigate the potential causes of observed failures of EDS prototypes that functioned well in a laboratory environment but failed after outdoor exposure. Experimental studies form the last two chapters of this dissertation. Different tests have been conducted on an EDS sample integrated with a PV cell to restore the efficiency of the cell after dust deposition. In order to evaluate the performance of the EDS in dust-particle removal, we have studied the particle size distribution on the EDS surface after each dust deposition and EDS cleaning cycle using a custom-built dust-deposition analyzer. Furthermore, we have pursued several experiments to examine how the geometric and operational EDS parameters affect particle charge via charge-to-mass-ratio measurements.

Return collectors are predominant organs for rubber-tyred subways to operatesince they ensure both the track circuit shunt and the traction current return. Po- sitioned at the interface between the track and the rolling stock, they are subjected to the disruptions linked to the train movement and the track irregularities. One of the most critical steps is the crossing of a switch nose.This study aims at determining the collector position during this crossing by means of a quasi-static analysis of the system. Two approaches are investigated. The first one brings into play a rigid contact and geometrical angles. It enables to model the crossing until the contact with the crossing nose. The diving capability of the collector is also taken into account. The second one is a standard  approach of the contact. A slight penetration is considered, which allows to grasp the contact with  the crossing nose. The second advantage  is to prepare the ground for a complete dynamical analysis. Both approaches are then implemented on Matlab to solve the equations. Finally the study of the switch crossing in nominal conditionsand a parametric analysis are achieved for a specified switch.

This work studies the performance of heat pipe solar collector for water heating. Experimental results are validated using numerical modeling. Homemade heat pipes with distilled water as a working fluid were used for experimental tests. Both natural and forced convective heat pipe condensing mechanisms are studied and their results are compared with conventional natural circulation solar water heating system. Cross flow and parallel flow heat exchanger were tested in forced type heat pipe condensing mechanism. Experimental and numerical results showed good agreement. Heat pipe solar collectors outperformed conventional solar collector because of their efficient heat transport method. Forced convective heat exchanger was found to give higher efficiency compared to natural convective heat pipe condensing system. However, natural convective heat pipe condensing is free from parasitic power and low system weight. It also showed appreciable system efficiency and can be further developed to be used in rural areas where grid electricity is scarce. Cross flow and parallel flow heat exchanger have been tested for forced convective heat pipe condensing mechanism and no appreciable difference was found due to higher fluid velocity in heat exchangers.