Desde a introdução do conceito de escritório aberto, o tipo de ocupação e a distribuição das cargas internas têm sofrido grandes mudanças, requerendo maior flexibilidade nos edifícios. Além disto, avaliações de desempenho de edifícios de escritórios da atualidade têm apresentado resultados que são fortes indicadores da necessidade de mudanças de conceitos de projeto, operação e uso de sistemas de condicionamento de ar, devido ao elevado nível de insatisfação dos usuários quanto ao conforto e à qualidade do ar. Para tentar solucionar estes problemas, outro conceito em distribuição de ar, já em uso nos países desenvolvidos, está começando a ser adotado também no Brasil; trata-se de insuflamento pelo piso, com difusores instalados em placas de piso elevado e nas estações de trabalho, que permitem flexibilidade e controle individual de vazão de ar. Neste trabalho foi feita a avaliação de sistema de condicionamento de ar com insuflamento pelo piso em um laboratório com condições controladas. O laboratório em que foram realizados os ensaios foi projetado e instalado com características similares àquelas de ambientes reais de edifícios de escritórios. Este fato, aliado à participação de usuários no processo de avaliação das condições de conforto térmico, tornaram possível a definição de parâmetros para a elaboração de projetos bem como para o estabelecimento de um modo eficaz de operação do sistema. O processo de avaliação das condições de conforto térmico no ambiente envolveu três etapas. Inicialmente, foram feitas medições das variáveis de conforto térmico no ambiente e de variáveis do sistema utilizando simuladores. Posteriormente, foi realizada a avaliação subjetiva do conforto térmico, com a substituição dos simuladores por pessoas no ambiente (usuários), nas mesmas condições da etapa anterior. Finalmente, foram feitas as medições das variáveis de conforto nas zonas de ocupação – micro climas – na condição de condicionamento individualizado, promovido por ajustes de vazão de ar e direcionamento do fluxo pelos usuários. Os resultados da avaliação permitem concluir que o sistema de condicionamento de ar com insuflamento pelo piso atende às expectativas para promover conforto térmico aos usuários de edifícios de escritórios com potencial de conservação de energia. / Since the introduction of the landscape office concept, the layout type and the internal loads distribution have changed significantly, requesting larger flexibility in the buildings. Besides, building performance evaluation applied to contemporary office buildings has shown that for most such buildings thermal comfort and air quality users level satisfaction is low. These facts are indicating that project concepts, operation and use of air conditioning systems need to be changed. In order to solve these problems, underfloor air supply is becoming a common practice also in Brazil. This system with floor and workstation diffusers allows flexibility and an individualized airflow control. In this work the evaluation of the underfloor air conditioning system was carried out in a laboratory facility with controlled conditions. The laboratory was designed and built up with similar characteristics to those of actual office buildings environments. This fact and the participation of users in the process of thermal comfort evaluation, made possible the definition of design parameters as well as the establishment of the system operation conditions in an effective way. The evaluation of the environment thermal comfort conditions was accomplished in three stages. Initially, measurements of thermal comfort and system variables were made using simulators. Later, in the same conditions of the previous stage, users (a sample of people) have evaluated, in a subjective way, the environment thermal comfort. Finally, measurements of the comfort variables were accomplished in the occupation areas - microclimates - in the condition of individualized conditioning, promoted by air flow adjustments and flow direction by the users. The results of the evaluation allow to conclude that the underfloor air conditioning system satisfies to the expectations to promote thermal comfort to the office building users with potential of energy conservation.

Made available in DSpace on 2016-03-15T19:21:34Z (GMT). No. of bitstreams: 1 Erika Ciconelli de Figueiredo.pdf: 19944207 bytes, checksum: a41457dbf4fa5d2e118844c77234cf6e (MD5) Previous issue date: 2011-08-09 / Fundação de Amparo a Pesquisa do Estado de São Paulo / This work has as goal to study the resultant daylight from International Style buildings openings in São Paulo, in Avenida Paulista and Berrini axis, analyzing illuminance distribution. The approach was done from the solar geometry and glass types point of view. The use of daylight and natural ventilation in buildings has always been part of architects challenges, nevertheless with the beginning of energetic crises during the 1970s, these issues became more important. However the concern with energy saving and use of natural resources are not usually demonstrated in the finished building. As São Paulo has a subtropical climate, the biggest concern is to avoid buildings inner heat, and the typical solution is the use of solar control glasses to reduce costs with air conditioning. Nevertheless even high performance glasses block a substantial part of daylight, beyond the heat. The compensation for low interior luminousness is done by artificial means, increasing unnecessarily buildings use and maintenance costs. Buildings from São Paulo, Brazil, Berlin and Frankfurt, Germany, were studied with local measurement and with floor modeling in Relux Professional 2010. Daylight distribution characteristics of each building were identified with the purpose of delineating potential projects improvements, focusing São Paulo daylight availability throughout the year The analysis results showed that international style façades have limitations to increase the use of daylight since the whole shell has a single treatment. Both in German and Brazilian buildings the daylight distribution followed a trendline, indicating the need of using other means to obtain illuminance levels with fewer variations between room endings / Este trabalho tem por finalidade estudar a luz natural resultante dos vãos dos edifícios de Estilo Internacional da cidade de São Paulo, nos eixos da Avenida Paulista e Avenida Engenheiro Luís Carlos Berrini, analisando a distribuição da iluminância. A abordagem foi feita do ponto de vista da geometria da insolação e dos tipos de vidros. O uso da iluminação e ventilação natural em edifícios sempre fez parte dos desafios enfrentados por arquitetos; no entanto, com o início da crise energética, na década de 70, essas questões ganharam maior importância. Contudo, a preocupação com a economia de energia e o uso de recursos naturais nem sempre se traduzem na obra finalizada. Como São Paulo é uma cidade de clima subtropical, a preocupação maior acaba sendo evitar o aquecimento interno dos edifícios, e a solução mais comum é o uso de vidros de controle solar para redução de gastos com ar-condicionado. Mesmo em vidros de alto desempenho, há o bloqueio de parte considerável da luz natural, além do calor. A compensação para a baixa luminosidade no interior do edifício se faz por meio da iluminação artificial, o que eleva desnecessariamente o custo do uso e da manutenção do edifício. Foram estudados edifícios de escritórios das cidades de São Paulo, no Brasil, Berlim e Frankfurt am Main, na Alemanha, com medições in loco e por meio da modelagem de pavimentos no programa Relux Professional 2010. As caracterísitcas da distribuição da luz natural de cada edifício foram identificadas com o objetivo de delinear possíveis melhorias projetuais, tendo em vista a disponibilidade de luz natural em São Paulo o ano todo. Os resultados das análises mostraram que as fachadas de modelo internacional apresentam limitações para aumentar o uso da luz natural por terem uma única solução plástica em toda a sua extensão. Tanto nos edifícios brasileiros como nos alemães, a distribuição luminosa acompanhou a mesma linha de tendência, indicando a necessidade de utilizar outros meios para obter níveis de iluminâncias internas com variações menores entre os extremos dos ambientes

Being the major energy consumer of electricity and natural gas, buildings consume more than 70% of electricity and 30% of natural gas. On the way to green buildings and zero energy buildings, investigation and improvement of energy efficiency of the buildings will result in significant reductions in energy demands and CO2 emissions / make cost savings and improve thermal comfort as well. Key steps of a successful green, energy efficient building can be summarized as whole building design, site design, building envelope design, lighting and day lighting design and HVAC system design. Energy Plus&reg / software is mainly developed to simulate the performance of the buildings in the view of the above listed points. The design of a building or the analysis of an existing building with the software will show how efficient the building is or will be, and also helps finding the best efficient choice of the whole building system. Thesis focuses on the effect of changes in building envelope properties. In Turkey, topic of green buildings has recently started to be studied. Therefore, this thesis aims to present efficient technologies providing energy savings in buildings, to present green building concept and alternative energy simulation software. In the context of this study, design, methods and material guidelines are introduced to reduce energy needs of buildings and to bring in the green building design concept. Building and system parameters to enhance building energy efficiency and energy savings together with green building principles are summarized. Moreover, whole building energy analysis methods and simulation steps are explained / year-round simulation is performed for a sample building / as a result, energy savings about 36% is achieved.

The intention of this study is to investigate the main source of unacceptable humidity levels at the U.S. Coast Guard Housing located in Bayamon, Puerto Rico. The aim of this research is to use a systematic approach to resolve the humidity and mold issues by testing the least expensive solutions first. This study involves the recording of indoor air quality conditions for six months as an analysis tool to investigate current air conditions and to document how physical changes to the air conditioning units will affect the resulting air conditions. This research will investigate and implement different approaches geared to solving the high humidity issues. Some of the most relevant changes that will be tested are the installation of heat pipe technology, the addition of fresh air to existing air conditioning units to create positive pressure, and the review of the space load design of currently installed air conditioning units to determine if the units were over-designed. In addition, this study will verify the relationship between energy-saving thermostats and high humidity, determine any connection between roof leaks and high humidity indoors, and determine the estimated cost to the Coast Guard to implement the recommended changes.

The demand for cooling and air-conditioning of building is increasingly ever growing. This increase is mostly due to population and economic growth in developing countries, and also desire for a higher quality of thermal comfort. Increase in the use of conventional cooling systems results in larger carbon footprint and more greenhouse gases considering their higher electricity consumption, and it occasionally creates peaks in electricity demand from power supply grid. Solar energy as a renewable energy source is an alternative to drive the cooling machines since the cooling load is generally high when solar radiation is high. This thesis examines the performance of PV/T solar collector manufactured by Solarus company in a solar cooling system for an office building in Dubai, New Delhi, Los Angeles and Cape Town. The study is carried out by analyzing climate data and the requirements for thermal comfort in office buildings. Cooling systems strongly depend on weather conditions and local climate. Cooling load of buildings depend on many parameters such as ambient temperature, indoor comfort temperature, solar gain to the building and internal gains including; number of occupant and electrical devices. The simulations were carried out by selecting a suitable thermally driven chiller and modeling it with PV/T solar collector in Polysun software. Fractional primary energy saving and solar fraction were introduced as key figures of the project to evaluate the performance of cooling system. Several parametric studies and simulations were determined according to PV/T aperture area and hot water storage tank volume. The fractional primary energy saving analysis revealed that thermally driven chillers, particularly adsorption chillers are not suitable to be utilizing in small size of solar cooling systems in hot and tropic climates such as Dubai and New Delhi. Adsorption chillers require more thermal energy to meet the cooling load in hot and dry climates. The adsorption chillers operate in their full capacity and in higher coefficient of performance when they run in a moderate climate since they can properly reject the exhaust heat. The simulation results also indicated that PV/T solar collector have higher efficiency in warmer climates, however it requires a larger size of PV/T collectors to supply the thermally driven chillers for providing cooling in hot climates. Therefore using an electrical chiller as backup gives much better results in terms of primary energy savings, since PV/T electrical production also can be used for backup electrical chiller in a net metering mechanism.

Thermal mass can be successfully implemented in the hot‐humid region of Austin, TX especially when well designed and with supplementary aids like nightcooling and day‐lighting. This study shows that in some situations thermal mass can be actually more beneficial at reducing electricity demands in hot‐humid regions than in the hot‐dry regions that are so emphasized in the literature. / text

Using chilled water within South African gold mines is paramount to the purpose of extracting gold ore efficiently. Using water for cooling, drilling and sweeping and the release of underground fissure water causes the accumulation of vast amounts of water in underground dams. Deep mines use cascading pump systems for dewatering, which is an electrical energy intensive dewatering method. Due to the recent equalisation of demand to generation capacity of electrical energy in South Africa, various methods towards demand side reduction have been implemented. With the introduction of a time-of-use (TOU) tariff structure by Eskom, the implementation of projects that shift load from peak TOU times to times of the day when electrical energy is less expensive has increased. To enable load shifting on mine dewatering pumps, preparation before and recovery after peak TOU is needed for effective results. This induces a preparation- and comeback load in the standard TOU. With an annual increase in TOU tariffs and the rate of increase of standard TOU being greater than that of the peak TOU, a reduction in electrical energy consumption before and after peak TOU is needed. To enable this, a step-by-step control technique was developed to promote the shifting of load from standard- to off-peak TOU, while still realising a full load shift from peak TOU. This technique entails dynamic control ranges of underground dam levels as opposed to the conventional constant control range method. Two case studies were used to test the developed technique. Results indicated significant additional financial savings when compared to conventional control methods. Additional savings of R1,096,056.65 and R579,394.27 per annum were respectively achieved for both case studies. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2014

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Η παρούσα διπλωματική εργασία πραγματεύεται τη διερεύνηση μεθόδου εξοικονόμησης ενέργειας σε ηλεκτροκίνητο όχημα, μέσω ελέγχου του κινηητήρα για την ελαχιστοποίηση των απωλειών του ηλεκτροκινητήριου συστήματος. Στη συγκεκριμένη περίπτωση, το ηλεκτροκινητήριο σύστημα αποτελείται από ασύγχρονο τριφασικό κινητήρα οδηγούμενο. από αντιστροφέα τάσης, ο οποίος τροφοδοτείται από συσσωρευτές. Η εργασία αυτή εκπονήθηκε στο Εργαστήριο Ηλεκτρομηχανικής Μετατροπής Ενέργειας του Τμήματος Ηλεκτρολόγων Μηχανικών της Πολυτεχνικής Σχολής του Πανεπιστημίου Πατρών. Σκοπός της διπλωματικής αυτής εργασίας είναι η ανάπτυξη της μεθόδου εξοικονόμησης ενέργειας σε ηλεκτροκίνητο όχημα, μέσω ελαχιστοποίησης των απωλειών του συστήματος. Η ελαχιστοποίηση των απωλειών υλοποιείται μεταβάλλοντας τη μαγνητική ροή διακένου του ασύγχρονου κινητήρα και το λόγο μετάδοσης του κιβωτίου ταχυτήτων. Απώτερος στόχος είναι η επέκταση της μεθόδου ελαχιστοποίησης των απωλειών του ηλεκτροκινητήριου συστήματος που αναπτύχθηκε στη διδακτορική διατριβή του Ε.Ρίκου, "Μέθοδοι Εξοικονόμησης Ενέργειας σε Ηλεκτροκίνητα Οχήματα". Πανεπιστήμιο Πατρών, Τμήμα Ηλεκτρολόγων Μηχανικών και Τεχνολογίας Υπολογιστών, Πάτρα 2005, στην περίπτωση κινητήριου συστήματος με ασύγχρονο τριφασικό κινητήρα και αντιστροφέα και επιβεβαίωση της αποτελεσματικότητάς της σε θεωρητικό επίπεδο, επίπεδο προσομοίωσης και πειραματικό. Αρχικά, εξετάζονται οι σχέσεις που περιγράφουν τις απώλειες ισχύος που παράγονται κατά τη λειτουργία του ηλεκτροκίνητου οχήματος, καθώς και η εξάρτησή τους από τη μαγνητική ροή διακένου και το λόγο μετάδοσης του κιβωτίου ταχυτήτων. Στη συνέχεια, δείχνεται με γραφικό τρόπο η δυνατότητα ελαχιστοποίησης των απωλειών του συστήματος με τη μεταβολή της μαγνητικής ροής διακένου και του λόγου μετάδοσης για δεδομένες μόνιμες καταστάσης λειτουργίας (ταχύτητα και δύναμη στους τροχούς του οχήματος). Το επόμενο βήμα είναι η επιβεβαίωση της θεωρητικής μελέτης μέσω προσομοίωσης η οποία γίνεται σε περιβάλλον Matlab/ Simulink. Τέλος, κατασκευάζονται στο εργαστήριο πειραματική διάταξη με χρήση της οποίας διεξάγονται μετρήσεις για την επιβεβαίωση και αξιολόγηση της θεωρητικής μελέτης. / This diploma thesis discourses the analysis of an energy saving method in an electrically powered vehicle by control of the electric motor for the loss minimization of the electromotion system. In this case, the electromotion system consists of an induction motor, driven by a voltage inverter which is fed by batteries. This project was based in the Laboratory of Electromechanincal Energy Conversion of School of Engineering of University of Patras. The objective of this project is the development of the method for energy saving in an electrically powered vehicle, through system losses minimization. The loss minimization is carried out by controlling motor air-gap magnetic flux and gear ratio. The aim of the project is the extension of the electromotion system loss minimization method which was developed in the doctoral thesis of Evangelos Rikos, "Methods of energy saving in electric vehicles", University of Patras, department of Electrical and Computer Engineering, Patras 2005 for the case of a three phase induction motor and inverter electric drive, as well as the confirmation of its effectiveness in theoretical level, simulation and experimental level. At first, an analysis of the equations that describe the losses of the electric vehicle is performed as well as their dependence from the air-gap flux and gear ratio. Following, is graphically demonstrated the ability to minimize the losses of the electromotion system by controlling the air-gap flux and the gear ratio for certain steady states (values of force and velocity at the vehicle's wheels). The next step is the confirmation of the theoretical analysis by simulation which is carried out in Matlab/Simulink environment. Finally, a three phase inverter is constructed with the use of which, the experiment is carried out on order to confirm the efficiency and evaluate the accuracy of the theoretical analysis