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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.
31

Energy Consumption Optimizations for 5G networks

Tran, Martina January 2019 (has links)
The importance of energy efficiency has grown alongside awareness of climate change due to the rapid increase of greenhouse gases. With the increasing trend regarding mobile subscribers, it is necessary to prevent an expansion of energy consumption via mobile networks. In this thesis, the energy optimization of the new radio access technology called 5G NR utilizing different sleep states to put base stations to sleep when they are not transmitting data is discussed. Energy savings and file latency with heterogeneous and super dense urban scenarios was evaluated through simulations with different network deployments. An updated power model has been proposed and the sensitivity of the new power model was analyzed by adjusting wake-up time and sleep factors. This showed that careful implementation is necessary when adjusting these parameter settings, although in most cases it did not change the end results by much. Since 5G NR has more potential in energy optimization compared to the previous generation mobile network 4G LTE, up to 4 sleep states was implemented on the NR base stations and one idle mode on LTE base stations. To mitigate unnecessary sleep, deactivation timers are used which decides when to put base stations to sleep. Without deactivation timers, the delay could increase significantly, while with deactivation timers the delay increase would only be a few percent. Up to 42.5% energy could be saved with LTE-NR non-standalone deployment and 72.7% energy with NR standalone deployment compared to LTE standalone deployment, while minimally impacting the delay on file by 1%.
32

Energy Optimal Path Planning Of An Unmanned Solar Powered Aircraft

Pinar, Erdem Emre 01 January 2013 (has links) (PDF)
In this thesis, energy optimal route of an unmanned solar powered air vehicle is obtained for the given mission constraints in order to sustain the maximum energy balance. The mission scenario and the constraints of the solar powered UAV are defined. Equations of motion are obtained for the UAV with respect to the chosen structural properties and aerodynamic parameters to achieve the given mission. Energy income and loss equations that state the energy balance, up to the position of the UAV inside the atmosphere are defined. The mathematical model and the cost function are defined according to the mission constraints, flight mechanics and energy balance equations to obtain the energy optimal path of the UAV. An available optimal control technique is chosen up to the mathematical model and the cost function in order to make the optimization. Energy optimal path of the UAV is presented with the other useful results. Optimal route and the other results are criticized by checking them with the critical positions of the sun rays.
33

Energieffektivisering av Byggnader : En kartläggning av energianvändningen på två förskolor och två skolor i Västerås med hjälp av timvärden

Al-Siyamer, Akram Dahham January 2017 (has links)
In the development of society towards renewable energy sources, the target in Sweden is 100% energy supply from renewable energy sources by the year 2040. This requires increased energy production from renewable, but also energy optimization of existing buildings. The housing and service sector which includes households and the public services account for about 40 % of Sweden’s total energy use. It is estimated that preschools and schools have an area of 35 million m² which have an energy savings potentials of 0,7-1 TWh in the electricity consumption and 0,9 TWh in energy use for heating. With regard to energy optimization, it is not only interesting to investigate a buildings total energy use on an annual or monthly basis, but also on shorter time intervals such hourly energy use, because of the uneven energy production of some renewable energy sources such as solar and wind. The purpose of this work is to study the energy usage for some of Västerås preschools and schools, and on the basis of it propose some energy optimization actions. To achieve this a literature study has been carried out to get knowledge about how energy usage is at preschools and schools, as well as to gain insight into what actions are appropriate to perform and how they savings look like. Other than that four objects has been studied, two preschools and two schools, one of each kind were chosen amongst those with the highest energy usage among Västerås city’s preschools and schools and one of each kind amongst those with the lowest usage. The annual energy usage have been calculated and been compared to the actual usage, and the monthly and hourly energy usage for district heating have been studied as well as the electricity usage along the day for different periods. The studied periods and energy usage shows that the energy usage, both for the monthly and hourly,  for the district heating moves with regards to the outdoor temperature with some exceptions. As for the electricity usage it shows that the energy usage is even with some exceptions and there is a difference between different outdoor temperature intervals. Some conclusions could be drawn among others that the objects with higher energy usage where older buildings and the objects with lower energy usage where newer ones. There are some energy optimizations actions for the objects which would lower the energy consumption, both for district heating and electricity usage.
34

An Adaptive Intelligent Integrated Lighting Control Approach for High-Performance Office Buildings

January 2015 (has links)
abstract: An acute and crucial societal problem is the energy consumed in existing commercial buildings. There are 1.5 million commercial buildings in the U.S. with only about 3% being built each year. Hence, existing buildings need to be properly operated and maintained for several decades. Application of integrated centralized control systems in buildings could lead to more than 50% energy savings. This research work demonstrates an innovative adaptive integrated lighting control approach which could achieve significant energy savings and increase indoor comfort in high performance office buildings. In the first phase of the study, a predictive algorithm was developed and validated through experiments in an actual test room. The objective was to regulate daylight on a specified work plane by controlling the blind slat angles. Furthermore, a sensor-based integrated adaptive lighting controller was designed in Simulink which included an innovative sensor optimization approach based on genetic algorithm to minimize the number of sensors and efficiently place them in the office. The controller was designed based on simple integral controllers. The objective of developed control algorithm was to improve the illuminance situation in the office through controlling the daylight and electrical lighting. To evaluate the performance of the system, the controller was applied on experimental office model in Lee et al.’s research study in 1998. The result of the developed control approach indicate a significantly improvement in lighting situation and 1-23% and 50-78% monthly electrical energy savings in the office model, compared to two static strategies when the blinds were left open and closed during the whole year respectively. / Dissertation/Thesis / Doctoral Dissertation Architecture 2015
35

Otimização do tempo de vida em redes de sensores sem fio utilizando algoritmo de energia e protocolo difusão direcionada / Optimization of lifetime in nets algorithm using wireless sensors, energy and targeted dissemination protocol

Alex Leal Ginatto 30 May 2008 (has links)
O notável desenvolvimento da indústria eletrônica observado nos últimos tempos tem permitido aplicações de conjuntos integrados de sensores em ambientes sem fio, conhecidos por wireless sensor networks (WSN), que passam por sensoriamento de processos industriais, ambientes tóxicos, projetos militares de monitoração de variáveis de segurança, até observação de fenômenos físicos naturais. Uma das principais especificações de uma rede WSN, o consumo de energia afeta diretamente a capacidade e tempo de vida útil do sistema, pois, na maioria dos casos, seus módulos possuem baterias independentes e sua substituição nem sempre é tarefa simples. Motivado pela necessidade de oferecer robustez e economia de energia nas redes WSN, o protocolo difusão direcionada se baseia na centralização de dados e a identificação de seus módulos é feita por meio de pares valor-atributo. Sua estrutura permite a adição de componentes de software que podem atuar na análise e modificação dos dados recebidos com o objetivo de alterar o protocolo original. O objetivo principal deste trabalho é investigar um método para otimização do uso de energia disponível em redes WSN com intuito de prolongar seu tempo de vida útil. O metódo consiste em analisar os valores das energias atribuídas aos módulos componentes da rede por meio de incorporação de um algoritmo de rotas baseado em energia ao protocolo difusão direcionada. Comparações de desempenho da rede em relação ao seu tempo de vida e energia dos módulos são realizadas utilizando o simulador NS-2. As simulações feitas em diversos cenários indicaram melhoria de desempenho em relação ao protocolo difusão direcionada original. Os cenários onde o protocolo original foi alterado apresentaram um número maior de rotas descobertas e possibilitaram um aumento de pelo menos 22% no tempo de vida da rede, em relação ao protocolo original. / The notable development of electronic industry in the last years allows the implementation of sensor integrated circuits in wireless environments, known as wireless sensor networks (WSN), which leads to industrial process sensing, toxic environments, military security monitor projects and natural physical phenomenon. As one of the main specifications of a WSN network, the energy consumption directly affects the capacity and the system useful lifetime, since most of the time its modules have independent batteries and their substitution is not always a simple task. Motivated by the need of offering robustness and energy economy for WSN networks, the directed diffusion protocol is data-centric based and its modules identification is made by attribute-value pairs. The directed diffusion structure enables the addition of software components which can act on the analysis and modification of received data with the objective of changing the original protocol. The main objective of this work is to investigate a method for optimization of available energy on WSN networks with the intention of increasing its useful lifetime. The method consists on analyzing the energy values attributed to the component modules of the network by incorporating an energy-based routing algorithm to directed diffusion protocol. Performance comparisons of the network related to its lifetime and modules energy are developed using the NS-2 simulator. Simulations performed in several scenarios indicated a better performance in relation to the original directed diffusion protocol. The scenarios where the original protocol was changed had larger number of discovered routes and allowed a rising of at least 22% on network lifetime, in relation to the original protocol.
36

Proactive Energy Optimization in Residential Buildings with Weather and Market Forecasts

Simmons, Cody Ryan 01 July 2019 (has links)
This work explores the development of a home energy management system (HEMS) that uses weather and market forecasts to optimize the usage of home appliances and to manage battery usage and solar power production. A Moving Horizon Estimation (MHE) application is used to find the unknown home model parameters. These parameters are then updated in a Model Predictive Controller (MPC) which optimizes and balances competing comfort and economic objectives. Combining MHE and MPC applications alleviates model complexity commonly seen in HEMS by using a lumped parameter model that is adapted to fit a high-fidelity model. HVAC on/off behaviors are simulated by using Mathematical Program with Complementary Constraints (MPCCs) and solved in near real-time with a nonlinear solver. Removing HVAC on/off as a discrete variable decreases potential solutions and consequently reduces solve time and increases the probability of reaching a more optimal solution. The results of this work indicate that energy management optimization significantly decreases energy costs and balances energy usage more effectively throughout the day compared to a home with regular temperature control. A case study for Phoenix, Arizona shows an energy reduction of 21% and a cost reduction of 40%. Homes using this home energy optimization will contribute less to the grid peak load and therefore, improve grid stability and reduce the amplitude of load following cycles for utilities. This case study combines renewable energy, energy storage, forecasts, cooling system, variable rate electricity plan and a multi-objective function allowing for a complete home energy optimization assessment. There remain several challenges, including improved forecast models, improved computational performance to allow the algorithms to run in real-time, and mixed empirical / first principles machine learning methods to guide the model structure.
37

Modelování, simulace a experimentální měření reakce systémů vytápění/vzduchotechniky na požadavky regulace / Modeling, simulation and experimental measurement of reaction of systems heating / ventilation requirements of regulation

Matějíček, Michal January 2019 (has links)
The diploma thesis deals with the behavior of technical systems of the student dormitory in Brno. The temperature and humidity climate was measured and evaluated in the building. The measurement is then compared with the computer simulation created in DesignBuilder. The geometric model of the building was created in Revit, which supports BIM technology. Based on the evaluation of the experiment, the optimization of the technical systems in the building was proposed.
38

Energy optimization of pulp drying, Södra Cell Värö : / Energioptimering av massatorkning på torkmaskinen vid Södra Cell Värö

Sundin, Emma January 2011 (has links)
The degree project was done at Södra Cell Värö with the purpose to investigate how the use of energy for pulp drying in a pulp dryer could be made more effective to decrease the energy consumption or increase the capacity. The pulp dryer is one of the machines that consumes the most energy at SCV. The air that dryes the pulp is heated by low pressure steam, and since the amount low pressure steam was limited, the purpose with the project was to investigate how the low pressure steam best could be used. If the drying capacity could be improved it could enable for an increase in production or a decrease low pressure steam consumption. The task was divided into: 1. Analysis of steam and condensate flows connected to the pulp dryer. Can they be adjusted to improve the drying capacity? 2. Investigation of possible sectors of application for hot air flows from vacuum pumps. 3. Investigation of the condensate system. Can condensate and flash steam be used in a better way to provide more steam to the pulp dryer? For task 1, air and energy balances were made ove the pulp dryer, then temperature, flow and moisture content were measured for all air flows in and out. To investigate how the consumption low pressure steam in the pulp dryer depends on the air flows in to the pulp dryer, tests were made where the rotation speed for the fans and the temperature for the air were varied. The result of measuring the air balance over the pulp dryer was that the same amount air was going in and out, which means that all the air was going in to the dryer preheated. The energy balance over the thermal recycling system showed that 40 % of the energy in outgoing air was being reused. Increasing the rotation speed from 750 rpm to 1000 rpm was favourable when the production was high. Increasing the temperature of the air in to the pulp dryer showed that the consumption low pressure steam decreased. Recommended rotation speeds: December – february: 1000 rpm, all levels of production mars – november: 1000 rpm for high production (over 3 bar low pressure steam to pulp dryer) 750 rpm for low production (below 3 bar low pressure steam to pulp dryer) For task 2, temperature, flow and moisture content were measured for all air flows out from the vacuum pumps. The air flows out from the vacuum pumps had a temperature of 40-50 °C, which was too low to be used for preheating of air to pulp dryer. For task 3, a mapping of the condensate system including all steam and condensate flows connected to the pulp dryer was made. The mapping was made in AutoCAD. Since the experiment with increased temperature of the air in to the pulp dryer showed that an increase in temperature caused the consumption low pressure steam to decrease, calculations of how much more the consumption low pressure steam could be decreased by switching to steam of a higher pressure for preaheating the drying air. By using only steam of higher pressure for air preheating, the amount available low pressure steam to the pulp dryer could be increased with 6 tonnes/h. / Examensarbetet utfördes på Södra Cell Värö med syfte att undersöka hur energianvändningen för massatorkning på torkmaskinen (TM) kunde effektiviseras för att ge lägre energiförbrukning eller högre kapacitet. TM är en av de mest energiförbrukande avdelningarna på bruket. Massan torkas där med luft som värms av processånga vilken utgörs av lågtrycksånga, och eftersom tillgången av lågtrycksånga var begränsad var det önskvärt att undersöka hur den kunde användas på mest effektiva sätt. Om torkkapaciteten kan förbättras kan det möjliggöra en ökning av produktionen alternativt en minskning av förbrukning av lågtrycksånga. Uppgiften delades upp i: 1. Analys av ång- och luftflöden kopplat till TM. Kan de justeras för att ge bättre torkkapacitet? 2. Undersökning av möjliga användningsområden för varma luftflöden från vakuumpumparna. 3. Undersökning av kondensatsystemet. Kan kondensat och flashånga utnyttjas på ett bättre sätt för att tillhandahålla mer ånga till TM? Till uppgift 1 ställdes luft- och energibalanser upp över TM, och sedan gjordes mätningar på temperatur, flöde och fukthalt på in- och utgående luftflöden. För att undersöka hur förbrukningen lågtrycksånga i torkskåpet påverkas av tilluften gjordes försök där varvtal på tilluftfläktar och temperatur på tilluft varierades. Resultatet av luftbalansmätningarna var att inget undertryck rådde över torkskåpet, vilket innebär att all tilluft gick förvärmd in till torkningen. Energibalans över värmeåtervinningssystemet visade att ca 40 % av energin i utgående våtluft återvinns. Försök med varvtal och temperatur på tilluft visade att en ökning av varvtal från 750 rpm till 1000 rpm var gynnsamt vid hög produktion, samt att en temperaturökning på tilluft minskade förbrukningen lågtrycksånga i torkskåpet. Rekommenderade körinställningar: December-februari: 1000 rpm, alla produktionsnivåer Mars-november: 1000 rpm vid hög produktion (över 3 bars tryck på lågtrycksångan till skåpet) 750 rpm vid låg produktion (under 3 bars tryck på lågtrycksångan till skåpet) Till uppgift 2 gjordes mätningar på temperatur, flöde och fukthalt på utgående luftflöden från vakuumpumpar. Luftflödena från vakuumpumpar höll en temperatur på 40-50 °C, vilket var för lågt för att kunna användas till att förvärma torkluft till TM. Till uppgift 3 gjordes en kartering av kondensatsystemet inkluderande alla ång- och kondensatflöden kopplade till massatorkningen. Karteringen utfördes i AutoCAD. Eftersom försöket med temperaturökning på tilluft visade att lågtrycksångförbrukningen i skåpet minskade med ökad temperatur på tilluft, beräknades hur stor en ytterligare besparing lågtrycksånga skulle kunna bli om all tilluft förvärmdes av mellantrycksånga. Genom att använda mellantrycksånga för att förvärma all tilluft till torkskåpet skulle mängden tillgänglig lågtrycksånga till torkskåpet kunna ökas med 6 ton/h.
39

Optimisation énergétique d'un véhicule hybride / Optimisation énergétique d'un véhicule hybride

Mokukcu, Mert 05 October 2018 (has links)
Les progrès technologiques augmentent la complexité des systèmes énergétiques, ce qui permet d'avoir variés sources et architectures possibles. Si le contexte économique et écologique est également pris en compte, l'industrie automobile est menée à aligner sa production sur des véhicules hybrides ou électriques qui disposent d'une gestion de l'énergie sophistiquée. Ainsi, les études pour la conception sont orientées à l'optimisation et à la gestion de l'énergie en tenant compte les tendances des constructeurs : i) augmenter les performances des véhicules, ii) avoir des véhicules moins polluants en réduisant la consommation de carburant et iii) diminuer le temps nécessaire à la conception et au processus de validation. Face à ces problèmes, une approche qui aide le concepteur à caractériser le système de gestion de l'énergie d'un VEH est proposée. Cette caractérisation consiste à : i) choisir l'architecture de la chaîne de traction, ii) le dimensionnement des composants (groupes) et iii) le contrôleur de gestion de l'énergie. Pour accomplir ces tâches, une méthode de modélisation énergétique fonctionnelle est proposée. Cette approche proposée à un niveau d'abstraction "juste nécessaire" qui permet d'avoir une analyse énergétique pour une série de cas d'utilisation. La méthode repose sur des boucles de contrôle locales, un contrôleur global et des équations de base et elle permet d'avoir une optimisation modulaire pour tout changement d'architecture. Prochaine étape de la validation est l'adaptation du modèle fonctionnel afin d'obtenir le contrôleur de haut niveau pour le niveau multi-physique avec deux étapes proposées : i) l'ajustement des paramètres des éléments fonctionnels et ii) l'interconnexion les modèles fonctionnels et multi-physiques. Après l'illustration du démonstrateur d'un VEH, trois stratégies de gestion de l'énergie sont proposées : i) fondée sur des règles, ii) fondée sur PFC avec fonctionnement de partage de besoin par priorisation et iii) fondée sur PFC avec fonctionnement boost. Les stratégies de gestion de l'énergie proposées sont ensuite comparées par indicateurs de performance (consommation de carburant, nombre de cycles marche/arrêt du groupe motopropulseur et consommation de carburant corrigée avec variation de l'état de charge du stockage électrique) avec des cas d'usages définis. / Technology advancements increase the complexity of energy systems which bring additional varieties of sources and possible architectures to choose. If the economic and ecological context is also included, the automobile industry is in_uenced to align their production to hybrid or battery electric vehicles that have sophisticated energy management system. Thus, researchers and designers have oriented their studies for system design, optimisation and energy management that take into consideration the constructor tendencies : i) increasing vehicle performances, ii) having less polluting vehicles by reducing fuel consumption and iii) decreasing the time needed for design and validation process. Against these problematics, an approach that assists the system designer to fully characterize the energy management system of a HEV is proposed. This characterization consists : i) choosing powertrain architecture, ii) component (units) sizing and iii) energy management controller. In order to accomplish these tasks, a functional energetic modelling method is proposed. Proposed functional modelling level has a level of abstraction _just necessary_ which permits to have energetic analysis for a series of use case. This method relies on local control loops, a global controller and basic equations and it allows to have a modular optimisation for any architecture changes. The second-stage in the validation is completed by adapting the functional model in order to obtain the high-level controller for the multi-physical level with two offered steps : i) adjustment the functional elements' parameters and ii) interconnection the functional and multi-physical models. After the illustration of the demonstrator of a HEV, three strategies for energy management is proposed : i) based on rules, ii) based on PFC with power sharing function and iii) based on PFC with booster function. The proposed energy management strategies then compared by performance indicators (fuel consumption, number of on/off cycles of engine powertrain and corrected fuel consumption with variation of state of charge of electrical storage) with defined use cases.
40

Energieffektivitet hos fönster - Idag och i framtiden : En analys samt komparativ studie av fönster för byggnader, med fokus på aeorgel-, vacuum och smarta-fönster

Tahan, Petrus January 2016 (has links)
Energieffektivisering börjar bli ett eftersträvande mål runtom i världen. Detta grundar sig i att energiförbrukningen för byggnader uppgår till ca 40 % globalt, en siffra som man vill få ner. Men att uppnå en energieffektiv byggnad är inte lätt. Detta kan göras på många och olika sätt. Ett av dem är att energieffektivisera fönstren, som är en byggnads svagaste punkt pga dess höga U-värde. Val av fönster är inte lätt, och det finns ett flertal alternativ att välja bland. I kalla klimat som Sverige söker man fönster med lågt U-värde och högt g-värde, samt en hög avskärmningsfaktor. I varmare länder vill man också ha ett lågt U-värde hos fönster men fokusen ligger främst på en låg avskärmningsfaktor. Syftet med uppsatsen var att hitta de mest energieffektiva fönstren, oavsett kostnad, för byggnader som befinner sig i länder med kallare klimat. Det var också av vikt att få veta lönsamheten för fönstren i fråga, därför har även kostnadsfrågor belysts. Metodvalen var informationssökning i olika databaser och litteratur samt att olika företag inom fönsterbranschen kontaktades, vilket ledde till att relevant och önskvärd information erhölls. Därefter fortskred arbetet genom kalkyleringar för energibalansen och lönsamheten. Vacuumfönster, aerogelfönster samt kromogena fönster hör till framtida fönster som kan tillföra positiva inverkan på energibalansen för byggnader. Men dessa fönster är i nuläget inte helt färdigutvecklade, fast har potential att bli världsledande. Vacuumfönster och kromogena fönster är i nuläget bättre lämpade för varmare klimat. Lyckas man komma längre med deras nutida utveckling är det inte omöjligt att anpassa de för kallare klimat. Aerogelfönster ger mest energibesparing vid byte av fönster, men pga vissa optiska egenskaper och komplicerad tillverkning av produkten är den i nuläget inte optimal vid ett fönsterbyte. De framtida fönstren är ej heller ekonomiskt försvarbara, det finns i dagsläget kommersiella energieffektiva fönster som är billigare att införskaffa och ger ett ansenligt bra resultat för en byggnads energibalans. / Energy optimization is starting to be a pursued worldwide main goal. This is based on the global energy consumption that occurs in buildings, which is about 40 percent. There is no doubt that this value needs to be lowered. But to achieve an energy efficient building is not easy. Although, this can be done in many and different ways. One of them is to optimize the windows, which is a buildings weakest point due to its high U-value.The choice of windows can be a harsh decision, there’s plenty of windows to choose among. In heating dominated climates, as the one in Sweden, it is necessary to choose windows with low U-values and high g-values, also a high solar heat gain coefficient/shading coefficient is required. A window with a low U-value is also important in cooling dominated climates but the main focus is instead on a low shading coefficient, which is not the case in this thesis. The purpose is to find the most energy efficient window that lowers the need for active heating in buildings, and also reveal and discuss the cost issues for the chosen windows.By searching in scientific databases and contacting companies active in the window industry the desired information was obtained. Calculations including the energy balance and present value were made, which gave an indication of the profitability for the different windows. Vacuum, aerogel and chromogenic window are examples of future windows which can have a positive impact on the energy balance in buildings. Yet these windows are currently not fully developed, but have potential to be highly valuable types of windows. Vacuum and chromogenic windows are better suited for cooling dominated climates. However if the development succeed where a big progress will be made it will not be impossible to suit them for heating dominated climates too. Aerogel windows have the best impact on the energy savings when replacing windows, but due to some optical attributes and a complicated manufacturing of the product aerogel windows are currently not an optimal choice for window replacement. The future windows isn’t either economically viable. For now, there are other commercially energy efficient windows that are cheaper to purchase. They also show an acceptable good result on the energy balance for a building.

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