• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 243
  • 48
  • 39
  • 17
  • 11
  • 8
  • 8
  • 7
  • 3
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • Tagged with
  • 480
  • 480
  • 136
  • 94
  • 93
  • 92
  • 89
  • 87
  • 71
  • 69
  • 68
  • 63
  • 58
  • 57
  • 55
  • 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.
221

Smart Manufacturing Using Control and Optimization

Harsha Naga Teja Nimmala (6849257) 16 October 2019 (has links)
<p>Energy management has become a major concern in the past two decades with the increasing energy prices, overutilization of natural resources and increased carbon emissions. According to the department of Energy the industrial sector solely consumes 22.4% of the energy produced in the country [1]. This calls for an urgent need for the industries to design and implement energy efficient practices by analyzing the energy consumption, electricity data and making use of energy efficient equipment. Although, utility companies are providing incentives to consumer participating in Demand Response programs, there isn’t an active implementation of energy management principles from the consumer’s side. Technological advancements in controls, automation, optimization and big data can be harnessed to achieve this which in other words is referred to as “Smart Manufacturing”. In this research energy management techniques have been designed for two SEU (Significant Energy Use) equipment HVAC systems, Compressors and load shifting in manufacturing environments using control and optimization.</p> <p>The addressed energy management techniques associated with each of the SEUs are very generic in nature which make them applicable for most of the industries. Firstly, the loads or the energy consuming equipment has been categorized into flexible and non-flexible loads based on their priority level and flexibility in running schedule. For the flexible loads, an optimal load scheduler has been modelled using Mixed Integer Linear Programming (MILP) method that find carries out load shifting by using the predicted demand of the rest of the plant and scheduling the loads during the low demand periods. The cases of interruptible loads and non-interruptible have been solved to demonstrate load shifting. This essentially resulted in lowering the peak demand and hence cost savings for both “Time-of-Use” and Demand based price schemes. </p> <p>The compressor load sharing problem was next considered for optimal distribution of loads among VFD equipped compressors running in parallel to meet the demand. The model is based on MILP problem and case studies was carried out for heavy duty (>10HP) and light duty compressors (<=10HP). Using the compressor scheduler, there was about 16% energy and cost saving for the light duty compressors and 14.6% for the heavy duty compressors</p> <p>HVAC systems being one of the major energy consumer in manufacturing industries was modelled using the generic lumped parameter method. An Electroplating facility named Electro-Spec was modelled in Simulink and was validated using the real data that was collected from the facility. The Mean Absolute Error (MAE) was about 0.39 for the model which is suitable for implementing controllers for the purpose of energy management. MATLAB and Simulink were used to design and implement the state-of-the-art Model Predictive Control for the purpose of energy efficient control. The MPC was chosen due to its ability to easily handle Multi Input Multi Output Systems, system constraints and its optimal nature. The MPC resulted in a temperature response with a rise time of 10 minutes and a steady state error of less than 0.001. Also from the input response, it was observed that the MPC provided just enough input for the temperature to stay at the set point and as a result led to about 27.6% energy and cost savings. Thus this research has a potential of energy and cost savings and can be readily applied to most of the manufacturing industries that use HVAC, Compressors and machines as their primary energy consumer.</p><br>
222

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>
223

Developing ESCO procedures for large telecommunication facilities using novel simulation techniques / J.F. van Rensburg

Van Rensburg, Johann Francois January 2006 (has links)
Thesis (Ph.D. (Electrical Engineering))--North-West University, Potchefstroom Campus, 2006.
224

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.
225

Opportunities for CO2 Reductions and CO2-Lean Energy Systems in Pulp and Paper Mills

Möllersten, Kenneth January 2002 (has links)
The risk for climate change is a growing concern for theglobal society. According to what is known as the Kyoto Protocol,developed countries have committed themselves to reduce theirgreenhouse gas (GHG) emissions. The purpose of this thesis hasbeen to analyse opportunities for CO2 reductions in Swedish pulpand paper mills. The pulp and paper industry accounts forsignificant shares of the Swedish utilisationof both electricityand, in particular, biomass fuels. In this thesis, it has been agoal to focus not only on the technical potential of alternativesfor CO2 reductions in the energy systems of pulp and paper mills,but also on analysing the costeffectiveness of the studiedmeasures. Moreover, the analysis has covered questions concerningthe capacity and willingness among the actors involved with thepulp and paper mills’energy systems to realise CO2reduction potentials. A broad techno-economical evaluation of available technologiesfor increased power production as well as more efficient energyutilisation is carried out. Furthermore, a more indepth analysisof pulp mill-based biomass energy with CO2 removal and permanentsequestration (BECS) is presented. An evaluation is made of thepotential for pulp and paper production with a negative CO2balance through the implementation of BECS. In recent yearsoutside suppliers, mainly energy service companies (ESCOs), havebegun to operate energy facilities in some Swedish pulp and papermills. Based on interviews with managers from pulp and papercompanies and ESCOs, the main driving forces behind theincreasing co-operation as well as the opportunities and riskswith energy related co-operation are presented. Furthermore, the technical possibility of carbon-negativitythrough the implementation of BECS is discussed in relation tocarbon management on both corporate and global levels. The extentto which CO2-reducing measures in pulp and paper mills arerealised will have an impact on Sweden’s capacity to reachCO2 reduction targets. Whether or not technologies for CO2capture and sequestration are developed and implemented inSwedish pulp mills has a very large impact on the size ofSweden’s long-term CO2 reduction potential. Moreover, thedevelopment of business and competence focus in pulp and papercompanies and ESCOs suggests that cooperation will become ofincreasing importance for future sustainable industrial energymanagement. <b>Keywords:</b>CO2 reduction, pulp and paper industry, energysystem, biomass, CO2 capture and sequestration, black liquor,gasification, power production, outsourcing, sustainable energymanagement
226

Solar Impulse - Around the World in a Solar Airplane

Leblois, Richard 09 May 2012 (has links) (PDF)
- Einführung in das Projekt Solar Impulse (Entstehung, Herausforderung, Errungenschaften) - Beschreibung der eingesetzten Software Tools zur Entwicklung des Flugzeuges - Fallbeispiele für den Einsatz von Mathcad
227

Analysis and Full-scale Experiment on Energy Consumption of Hotels in Taiwan

Wang, You-Hsuan 13 June 2003 (has links)
Being located in subtropical area, the weather in Taiwan is constantly hot and humid which imposes huge cooling load on buildings. Especially, the economic booms in Taiwan further boosted power demand, and worsened the power shortage situation. Dr. H.T. Lin and Dr. K.H. Yang had conducted systematic research since mid-1980s, which constructed a solid ground in this field in Taiwan. Among these results, the ENVLOAD index has become legal binding since 1997 while the PACS index is now under investigation. However, it is in short of analysis and full-scale experimental investigation on energy use of hotels in Taiwan. Therefore, the establishment of the EUI and DUI indexes in Taiwan is the goal of this study. A simplified calculation method has been established in analyzing the energy use and demand use of hotels in Taiwan, by normalizing experimental data from full-scale tests. The result can be drawn accurately based on a few terms, which are available from daily building operations such as occupancy, and is thus practically straightforward and easy to use. In addition, the accuracy was validated by experiments performed and data collected through information technology with Internet access in 4 different forms, which yielded successful results. It is anticipated that the calculation methodology developed in this study on EUI and DUI, and the experimental validation would provide a foundation for the establishment of hotel building energy codes in Taiwan in the future.
228

Opportunities for CO2 Reductions and CO2-Lean Energy Systems in Pulp and Paper Mills

Möllersten, Kenneth January 2002 (has links)
<p>The risk for climate change is a growing concern for theglobal society. According to what is known as the Kyoto Protocol,developed countries have committed themselves to reduce theirgreenhouse gas (GHG) emissions. The purpose of this thesis hasbeen to analyse opportunities for CO2 reductions in Swedish pulpand paper mills. The pulp and paper industry accounts forsignificant shares of the Swedish utilisationof both electricityand, in particular, biomass fuels. In this thesis, it has been agoal to focus not only on the technical potential of alternativesfor CO2 reductions in the energy systems of pulp and paper mills,but also on analysing the costeffectiveness of the studiedmeasures. Moreover, the analysis has covered questions concerningthe capacity and willingness among the actors involved with thepulp and paper mills’energy systems to realise CO2reduction potentials.</p><p>A broad techno-economical evaluation of available technologiesfor increased power production as well as more efficient energyutilisation is carried out. Furthermore, a more indepth analysisof pulp mill-based biomass energy with CO2 removal and permanentsequestration (BECS) is presented. An evaluation is made of thepotential for pulp and paper production with a negative CO2balance through the implementation of BECS. In recent yearsoutside suppliers, mainly energy service companies (ESCOs), havebegun to operate energy facilities in some Swedish pulp and papermills. Based on interviews with managers from pulp and papercompanies and ESCOs, the main driving forces behind theincreasing co-operation as well as the opportunities and riskswith energy related co-operation are presented.</p><p>Furthermore, the technical possibility of carbon-negativitythrough the implementation of BECS is discussed in relation tocarbon management on both corporate and global levels. The extentto which CO2-reducing measures in pulp and paper mills arerealised will have an impact on Sweden’s capacity to reachCO2 reduction targets. Whether or not technologies for CO2capture and sequestration are developed and implemented inSwedish pulp mills has a very large impact on the size ofSweden’s long-term CO2 reduction potential. Moreover, thedevelopment of business and competence focus in pulp and papercompanies and ESCOs suggests that cooperation will become ofincreasing importance for future sustainable industrial energymanagement.</p><p><b>Keywords:</b>CO2 reduction, pulp and paper industry, energysystem, biomass, CO2 capture and sequestration, black liquor,gasification, power production, outsourcing, sustainable energymanagement</p>
229

Seamless design of energy management systems

Huang, Renke 08 June 2015 (has links)
The contributions of the research are (a) an infrastructure of data acquisition systems that provides the necessary information for an automated EMS system enabling autonomous distributed state estimation, model validation, simplified protection, and seamless integration of other EMS applications, (b) an object-oriented, interoperable, and unified component model that can be seamlessly integrated with a variety of applications of the EMS, (c) a distributed dynamic state estimator (DDSE) based on the proposed data acquisition system and the object-oriented, interoperable, and unified component model, (d) a physically-based synchronous machine model, which is expressed in terms of the actual self and mutual inductances of the synchronous machine windings as a function of rotor position, for the purpose of synchronous machine parameters identification, and (e) a robust and highly efficient algorithm for the optimal power flow (OPF) problem, one of the most important applications of the EMS, based on the validated states and models of the power system provided by the proposed DDSE.
230

Optimising the operation of underground mine refrigeration plants and ventilation fans for minimum electricity cost / Christopher Swart

Swart, Christopher January 2003 (has links)
This study describes the development and use of a mathematical model that will enable mine operators to minimise the costs of electricity consumed by the ventilation and refrigeration systems used for environmental control in deep mines. This model was calibrated and tested by using actual data from a gold mine near Welkom in South Africa. In a first simulation, the mine's current practice of controlling conditions to a wet bulb temperature (Twb) of 25S°C, was optimised. The model demonstrated that this environmental condition could be sustained at lower electricity consumption. In so doing, the mine realised a saving of 30 000 kWh per day. The energy saving and load management led to a cost saving of R 1.5 million per year. However, a better indicator of environmental conditions is the Air Cooling Power index, (ACP). Research has shown that for hard physical work in hot conditions workers need an ACP of 300 w/m2. It was found that the case study mine actually supplied their workplace with a cooling capacity of 422 w/m2. The new model optimised the refrigeration and ventilation systems in such a manner that the workers were supplied with exactly 300 w/m2, no more and no less. It was found that by doing this, an electricity saving of 57 600 kWh per day could be realised when compared with the current mine practices. The energy saving and load management led to a potential cost saving of R 2.55 million per year. (Certain capital costs, such as for variable speed drives may have to be incurred to realise these savings.) The new model could be further extended to take advantage of the new Real Time Price offerings from Eskom It will be able to identify an operating point for the refrigeration and ventilation systems to supply 300 w/m2 for the workers, in real time, at the lowest electricity cost. / Thesis (Ph.D. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2004.

Page generated in 0.0471 seconds