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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.
601

Kuwait Residential Energy Outlook: Modeling the Diffusion of Energy Conservation Measures

January 2019 (has links)
abstract: The residential building sector accounts for more than 26% of the global energy consumption and 17% of global CO2 emissions. Due to the low cost of electricity in Kuwait and increase of population, Kuwaiti electricity consumption tripled during the past 30 years and is expected to increase by 20% by 2027. In this dissertation, a framework is developed to assess energy savings techniques to help policy-makers make educated decisions. The Kuwait residential energy outlook is studied by modeling the baseline energy consumption and the diffusion of energy conservation measures (ECMs) to identify the impacts on household energy consumption and CO2 emissions. The energy resources and power generation in Kuwait were studied. The characteristics of the residential buildings along with energy codes of practice were investigated and four building archetypes were developed. Moreover, a baseline of end-use electricity consumption and demand was developed. Furthermore, the baseline energy consumption and demand were projected till 2040. It was found that by 2040, energy consumption would double with most of the usage being from AC. While with lighting, there is a negligible increase in consumption due to a projected shift towards more efficient lighting. Peak demand loads are expected to increase by an average growth rate of 2.9% per year. Moreover, the diffusion of different ECMs in the residential sector was modeled through four diffusion scenarios to estimate ECM adoption rates. ECMs’ impact on CO2 emissions and energy consumption of residential buildings in Kuwait was evaluated and the cost of conserved energy (CCE) and annual energy savings for each measure was calculated. AC ECMs exhibited the highest cumulative savings, whereas lighting ECMs showed an immediate energy impact. None of the ECMs in the study were cost effective due to the high subsidy rate (95%), therefore, the impact of ECMs at different subsidy and rebate rates was studied. At 75% subsidized utility price and 40% rebate only on appliances, most of ECMs will be cost effective with high energy savings. Moreover, by imposing charges of $35/ton of CO2, most ECMs will be cost effective. / Dissertation/Thesis / Doctoral Dissertation Mechanical Engineering 2019
602

Building Energy Model Calibration for Retrofit Decision Making

Johnson, Nicolas R. 23 March 2017 (has links)
Accommodating the continued increase in energy demand in the face of global climate change has been a worldwide concern. With buildings in the US consuming nearly 40% of national energy, a concerted effort must be given to reduce building energy consumption. As new buildings continue to improve their efficiency through more restrictive energy codes, the other 76.9 billion square feet of current building stock falls further behind. The rate at which current buildings are being retrofit is not enough and better tools are needed to access the benefits of retrofits and the uncertainties associated with them. This study proposes a stochastic method of building energy model calibration coupled with a monthly normative building simulation addressed in ISO 13890. This approach takes advantage of the great efficiency of Latin Hypercube Sampling and the lightweight normative building simulation method, to deliver a set of calibrated solutions to assess the effectiveness of energy conservation measure, making uncertainty a part of the modeling process. A case study on a mixed-use university building is conducted to show the strength and performance of this simple method. Limitations and future concerns are also addressed.
603

Urban Geocomputation: Two Studies on Urban Form and its Role in Altering Climate

Voelkel, Jackson Lee 20 March 2018 (has links)
Our climate and our cities are changing. Though their changes are not completely dependent upon one another, there is still a coupling effect between them. This study assesses the role of urban form as it pertains to elements of climate change. It is comprised of two essays intended for publication. The first of these essays addresses the feedbacks between urban form, energy consumption, and rising global temperatures. The second essay looks at one particular factor of urban form--tree type--as it pertains to air pollution and urban heat island mitigation. Both papers use the analytical approaches necessary to answer the questions they pose, not ubiquitous over-generalizing modeling software or methods found often in the literature. As seen in the analyses, this practice--known as geocomputation--allows for a deeper and more accurate description of complex spatial relationships.
604

Plan and Reality : Municipal Energy Plans and Development of Local Energy Systems

Stenlund Nilsson Ivner, Jenny January 2006 (has links)
<p>Enligt lagen om kommunal energiplanering ska varje svensk kommun ha en energiplan för tillförsel för tillförsel och användning av energi. Huruvida energiplanering är ett bra sätt att styra det kommunala energisystemet är dock omdebatterat. Denna avhandling studerar innehåll i, och implementering av, ett antal svenska kommunala energiplaner. Energiplanernas effektivitet studeras på två nivåer: uppfyllelse av mål och visioner i planerna, samt hur detta bidrar till att uppfylla de nationella energipolitiska målen.</p><p>Forskningen baseras på tre studier: en studie av innehållet i tolv energiplaner från Östergötland, en studie av mål och visioner i sju energiplaner och hur energisystem utvecklats efter energiplanerna antagits, samt en fallstudie av Kungälvs kommun där mål och måluppfyllelse studerats mer utförligt. Innehåll och målformuleringar i energiplanerna har analyserats med avseende på miljö, effektiv energianvändning och systemnivå. Mål och måluppfyllelse har även analyserats med avseende på aktörer.</p><p>Resultaten visar på att de studerade energiplanerna har smal systemsyn och att de miljöanalyser som finns i planerna är undermåliga. Energiplaneringen har varit effektiv till viss del. Bäst måluppfyllelse har kommunerna när det gäller mål på en relativt låg systemnivå och när det är kommunen själv som äger frågan, exempelvis fjärrvärmeutbyggnad och energieffektivisering av kommunens lokaler. När det gäller utvecklingens bidrag till de nationella energipolitiska målen är resultaten varierande: användning av biobränslen har ökat avsevärt, medan självförsörjningsgraden på el bara ökat något. Bäst är utvecklingen när det gäller minskade koldioxidutsläpp.</p><p>Baserat på bristerna som upptäckts i de studerade energiplanerna och dess implementering förs en diskussion kring möjligheter att öka energiplaneringens effektivitet och vidga systemsynen. Förbättringar som diskuteras är att stärka kopplingen till fysisk planering, och att inkludera medborgarmedverkan och miljöbedömningar. Om kopplingen till energifrågor stärks i översiktlig planering och om även privata aktörer kommer till tals under planeringsprocessen, skulle detta kunna underlätta implementering av energiplanerna. Miljöbedömningar i sin tur kan bidra med en vidare systemsyn om mer relevanta mål i planerna. Slutligen föreslås att ramverket för miljöbedömning av planer och program (2001/42/EC) kan användas vid energiplanering eftersom det framhåller vikten av breda analyser, samråd med privata aktörer och miljöbedömningar.</p> / <p>Swedish municipalities are required to produce a municipal energy plan for energy supply and use. Whether energy planning is suitable to manage local energy systems, however, is subject to debate. This thesis explores municipal energy planning and development of local energy systems after energy plans were adopted to examine whether energy planning is effective. The effectiveness of energy planning is studied on two levels: in terms of whether goals in energy plans were implemented, and whether energy planning contributes to fulfilling national energy policy goals.</p><p>The research is based on three studies. In the first, the scope of twelve municipal energy plans from a Swedish region was assessed. In the second study, goals and visions in seven energy plans were analysed and compared to the development of the local energy systems. The third case involved Kungälv municipality, where the implementation of goals in its energy plan was studied more thoroughly. Scopes and goals in the energy plans were analysed from three perspectives: the environment, energy efficiency and the systems level. Goals and development were also analysed from an actor’s perspective.</p><p>The results show that the scopes of the studied energy plans have narrow systems boundaries, and that the environmental analyses presented in the plans are very basic. Energy planning was found to have been fairly effective in terms of fulfilment of goals in energy plans. Most positive developments are for goals on a relatively low systems level when the local authority owns the issue, for example district heating expansion and energy efficiency measures in public buildings. When it comes to contributing to national energy policy goals, results vary; use of biomass has increased, but selfsufficiency in electricity supply has increased only slightly. The most favourable development when it comes to energy-related emissions is the reduction of carbon dioxide.</p><p>Based on shortcomings identified in the studied energy plans and implementation, possibilities to increase the effectiveness and widen the scope of energy planning are discussed. Improvements are discussed in terms of urban planning as well as participative planning, and with respect to the environmental assessment of plans. If energy issues are included in urban planning and a participatory planning approach is used, this could facilitate the implementation of energy plans. Including environmental assessment could facilitate wide scopes and more relevant goals. It is also proposed that the EU framework for environmental assessment of plans and programmes (2001/42/EC) can be used for energy planning, since it includes a comprehensive approach, public participation, and environmental assessment.</p>
605

EM-MAC : an energy-aware multi-channel medium access control protocol for multi-hop wireless networks

Sivanantha, Akhil 22 March 2012 (has links)
The stupendous growth in wireless and mobile devices in the recent years has prompted researchers to look at innovative approaches that enable effective use of the available resources. In this thesis, we propose a medium access control (MAC) protocol, referred to as EM-MAC, that enables wireless devices with multi-channel access capabilities while minimizing energy consumption. EM-MAC relies on iMAC's efficient channel selection mechanism to resolve the medium contention on the common control channel, and to select the best available data channel for data communication. Our protocol saves energy by allowing devices that have not gained access to the medium to switch to doze mode until the channel becomes idle again. The pair of devices that gains access to the data channel reserves and uses the channel until the end of the reservation period. At the end of each reservation period, devices belonging to a given data channel contend again for the medium, and only the pair of devices that wins access to the medium is allowed to communicate on the channel while all other devices switch to doze mode. Using simulations, we show that EM-MAC yields substantial energy savings when compared with iMAC. / Graduation date: 2012
606

Plan and Reality : Municipal Energy Plans and Development of Local Energy Systems

Stenlund Nilsson Ivner, Jenny January 2006 (has links)
Enligt lagen om kommunal energiplanering ska varje svensk kommun ha en energiplan för tillförsel för tillförsel och användning av energi. Huruvida energiplanering är ett bra sätt att styra det kommunala energisystemet är dock omdebatterat. Denna avhandling studerar innehåll i, och implementering av, ett antal svenska kommunala energiplaner. Energiplanernas effektivitet studeras på två nivåer: uppfyllelse av mål och visioner i planerna, samt hur detta bidrar till att uppfylla de nationella energipolitiska målen. Forskningen baseras på tre studier: en studie av innehållet i tolv energiplaner från Östergötland, en studie av mål och visioner i sju energiplaner och hur energisystem utvecklats efter energiplanerna antagits, samt en fallstudie av Kungälvs kommun där mål och måluppfyllelse studerats mer utförligt. Innehåll och målformuleringar i energiplanerna har analyserats med avseende på miljö, effektiv energianvändning och systemnivå. Mål och måluppfyllelse har även analyserats med avseende på aktörer. Resultaten visar på att de studerade energiplanerna har smal systemsyn och att de miljöanalyser som finns i planerna är undermåliga. Energiplaneringen har varit effektiv till viss del. Bäst måluppfyllelse har kommunerna när det gäller mål på en relativt låg systemnivå och när det är kommunen själv som äger frågan, exempelvis fjärrvärmeutbyggnad och energieffektivisering av kommunens lokaler. När det gäller utvecklingens bidrag till de nationella energipolitiska målen är resultaten varierande: användning av biobränslen har ökat avsevärt, medan självförsörjningsgraden på el bara ökat något. Bäst är utvecklingen när det gäller minskade koldioxidutsläpp. Baserat på bristerna som upptäckts i de studerade energiplanerna och dess implementering förs en diskussion kring möjligheter att öka energiplaneringens effektivitet och vidga systemsynen. Förbättringar som diskuteras är att stärka kopplingen till fysisk planering, och att inkludera medborgarmedverkan och miljöbedömningar. Om kopplingen till energifrågor stärks i översiktlig planering och om även privata aktörer kommer till tals under planeringsprocessen, skulle detta kunna underlätta implementering av energiplanerna. Miljöbedömningar i sin tur kan bidra med en vidare systemsyn om mer relevanta mål i planerna. Slutligen föreslås att ramverket för miljöbedömning av planer och program (2001/42/EC) kan användas vid energiplanering eftersom det framhåller vikten av breda analyser, samråd med privata aktörer och miljöbedömningar. / Swedish municipalities are required to produce a municipal energy plan for energy supply and use. Whether energy planning is suitable to manage local energy systems, however, is subject to debate. This thesis explores municipal energy planning and development of local energy systems after energy plans were adopted to examine whether energy planning is effective. The effectiveness of energy planning is studied on two levels: in terms of whether goals in energy plans were implemented, and whether energy planning contributes to fulfilling national energy policy goals. The research is based on three studies. In the first, the scope of twelve municipal energy plans from a Swedish region was assessed. In the second study, goals and visions in seven energy plans were analysed and compared to the development of the local energy systems. The third case involved Kungälv municipality, where the implementation of goals in its energy plan was studied more thoroughly. Scopes and goals in the energy plans were analysed from three perspectives: the environment, energy efficiency and the systems level. Goals and development were also analysed from an actor’s perspective. The results show that the scopes of the studied energy plans have narrow systems boundaries, and that the environmental analyses presented in the plans are very basic. Energy planning was found to have been fairly effective in terms of fulfilment of goals in energy plans. Most positive developments are for goals on a relatively low systems level when the local authority owns the issue, for example district heating expansion and energy efficiency measures in public buildings. When it comes to contributing to national energy policy goals, results vary; use of biomass has increased, but selfsufficiency in electricity supply has increased only slightly. The most favourable development when it comes to energy-related emissions is the reduction of carbon dioxide. Based on shortcomings identified in the studied energy plans and implementation, possibilities to increase the effectiveness and widen the scope of energy planning are discussed. Improvements are discussed in terms of urban planning as well as participative planning, and with respect to the environmental assessment of plans. If energy issues are included in urban planning and a participatory planning approach is used, this could facilitate the implementation of energy plans. Including environmental assessment could facilitate wide scopes and more relevant goals. It is also proposed that the EU framework for environmental assessment of plans and programmes (2001/42/EC) can be used for energy planning, since it includes a comprehensive approach, public participation, and environmental assessment.
607

Efficiency Enhancement Techniques for Switched Mode Power Electronics

Zhao, April (Yang) 29 August 2011 (has links)
In the design of the state-of-the-art electronic products, power management circuits play a very important role for the enhancement of overall system efficiency. Switched mode DC-DC converter is an increasingly popular power management circuit due to its superior power conversion efficiency. This thesis introduces two efficiency optimization techniques for switched mode power electronic circuits. One is dead-time optimization. This technique can automatically adjust the dead-time on-the-fly according to the circuit operating conditions. Second, an energy conservation based high-efficiency dimmable multi-channel LED driver is discussed. An auxiliary power switched is use to allow free wheeling of the inductor current during the load disconnect period. The sequential burst mode PWM current sharing scheme with dimming capability can effectively reduce design complexity and cost. The proposed LED driver provides a practical solution for the realization of LED BLU in the flat panel TVs with local dimming capability according to the video content.
608

Efficiency Enhancement Techniques for Switched Mode Power Electronics

Zhao, April (Yang) 29 August 2011 (has links)
In the design of the state-of-the-art electronic products, power management circuits play a very important role for the enhancement of overall system efficiency. Switched mode DC-DC converter is an increasingly popular power management circuit due to its superior power conversion efficiency. This thesis introduces two efficiency optimization techniques for switched mode power electronic circuits. One is dead-time optimization. This technique can automatically adjust the dead-time on-the-fly according to the circuit operating conditions. Second, an energy conservation based high-efficiency dimmable multi-channel LED driver is discussed. An auxiliary power switched is use to allow free wheeling of the inductor current during the load disconnect period. The sequential burst mode PWM current sharing scheme with dimming capability can effectively reduce design complexity and cost. The proposed LED driver provides a practical solution for the realization of LED BLU in the flat panel TVs with local dimming capability according to the video content.
609

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.
610

Energieffektivisering av industribelysning : Planering av belysningsanläggning i mekanisk verkstad / Planning of energy efficient lighting system in engineering workshop

Ågren, Sebastian January 2012 (has links)
In Uppsala, Sweden, Vattenfall has a combined heat and power plant. On the premises there is an engineering workshop with old fluorescent and mercury lamps that need to be replaced. This provides a great opportunity to save energy and money by installing more efficient lighting. The main purpose of this study was to present two functional and energy efficient lighting systems including control system. The lighting systems were designed by investigating the working environment, measuring illuminance and by simulations in the software DIALux. Additionally Life Cycle Cost (LCC) was used as an instrument of comparison. One alternative was designed using mainly modern T5 fluorescent lighting. For the other alternative powerful LED-lamps were chosen as the primary light source. The simulations showed the two alternatives to be equally good in regard to performance and energy saving potential. With sustained illuminance level the installed power of both systems was around 34 kW ascompared to 54 kW, the estimated value of the existing lighting system. The LCC, however, differed significantly with the fluorescent alternative having a total cost of 1.1 million SEK over a 20 year period while the same number for the LED alternative being 2.2 million SEK. The difference in LCC makes fluorescent lighting the preferable alternative. The present consumption is estimated to 142 MWh. The fluorescent lighting alternative would have an approximated energy consumption of 78.6 MWh including a control system, giving an energy saving potential of 45 %.

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