• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 12
  • 7
  • 2
  • 1
  • 1
  • Tagged with
  • 26
  • 26
  • 11
  • 8
  • 6
  • 5
  • 5
  • 5
  • 4
  • 4
  • 4
  • 4
  • 3
  • 3
  • 3
  • 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.
1

Minimizing Energy Consumption in a Water Distribution System: A Systems Modeling Approach

Johnston, John 2011 May 1900 (has links)
In a water distribution system from groundwater supply, the bulk of energy consumption is expended at pump stations. These pumps pressurize the water and transport it from the aquifer to the distribution system and to elevated storage tanks. Each pump in the system has a range of possible operating conditions with varying flow rates, hydraulic head imparted, and hydraulic efficiencies. In this research, the water distribution system of a mid-sized city in a subtropical climate is modeled and optimized in order to minimize the energy usage of its fourteen pumps. A simplified model of the pipes, pumps, and storage tanks is designed using freely-available EPANET hydraulic modeling software. Physical and operational parameters of this model are calibrated against five weeks of observed data using a genetic algorithm to predict storage tank volume given a forecasted system demand. Uncertainty analysis on the calibrated parameters is performed to assess model sensitivity. Finally, the pumping schedule for the system's fourteen pumps is optimized using a genetic algorithm in order to minimize total energy use across a 24-hour period.
2

Feasibility of novel integrated dividing-wall batch reactive distillation processes for the synthesis of methyl decanoate

Aqar, D.Y., Rahmanian, Nejat, Mujtaba, Iqbal 15 March 2018 (has links)
Yes / The production of methyl decanoate (MeDC) through esterification of decanoic acid (DeC) with methanol by reactive distillation is operationally challenging and energy-intensive due to the complicated behaviour of the reaction system and the difficulty of retaining the reactants together in the reaction region. Methanol being the lightest component in the mixture can separate itself from the reactant DeC as the distillation proceeds which will cause a massive reduction in the conversion of DeC utilizing either a batch or continuous distillation process. Aiming to overcome this type of the potential problem, novel integrated divided-wall batch reactive distillation configuration (i-DWBD) with recycling from the distillate tank is established in this study and is examined in detail. This study has clearly demonstrated that the integrated divided-wall batch reactive distillation column (i-DWBD) is superior to the traditional conventional batch distillation (CBD) and both the divided-wall (DWBD), and split reflux divided-wall (sr-DWBD) batch reactive distillation configurations in terms of maximum achievable purity of MeDC and higher conversion of DeC into MeDC. In addition, significant batch time and energy savings are possible when the i-DWBD is operated in multi-reflux mode.
3

Synthesis of methyl decanoate using different types of batch reactive distillation systems

Aqar, D.Y., Rahmanian, Nejat, Mujtaba, Iqbal 22 March 2017 (has links)
Yes / Methyl Decanoate (MeDC) is a Fatty Acid Methyl Ester (FAME) and is an important chemical compound with global production of 31 million tons per year. However, synthesis of methyl decanoate (MeDC) via esterification of Decanoic Acid (DeC) with methanol by reactive distillation is operationally challenging due to difficulty of keeping the reactants together in the reaction zone as methanol being the lightest component in the mixture can separate itself easily form the other reactant deteriorating significantly the conversion of DeC using either conventional batch or continuous distillation column. This is probably the main reason for not applying the conventional route for MeDC synthesis. Whether Semi-batch Distillation column (SBD) and the recently developed Integrated Conventional Batch Distillation column (i-CBD) offer the possibility of revisiting such chemical reactions for the synthesis of MeDC is the focus of this paper. The minimum energy consumption (Qtot) as the performance measure is used to evaluate the performances of each of these reactive column configurations for different range of methyl decanoate purity and the amount of product. It is observed that the use of i-CBD column provides much better performance than SBD column in terms of the production time and the maximum energy savings when excess methanol is used in the feed. However, the SBD column is found to perform better than the i-CBD column when both reactants in the feed are in equal amount. Also, the optimization results for a given separation task show that the performance of two-reflux intervals strategy is superior to the single-reflux interval in terms of operating batch time, and energy usage rate in the SBD process at equimolar ratio.
4

Mapping and analysis of an internal heating network at Holmen Paper Braviken

Forsell, Ludwig, Samuelsson, Ebba January 2023 (has links)
The pulp and paper industry is the most energy intensive industry in Sweden. Most of the energy usedaims to supply the large amount of heat to the production processes that is required to produce pulp andpaper . By increasing the energy efficiency of paper mills, there is great potential to reduce productioncosts and reduce its environmental impact. This project involves mapping, analyzing and investigation ofmeasures that can contribute to increased thermal efficiency of an internal heating network at Holmen’spaper mill, Braviken. The heating network, called VVG, utilises excess heat from the pulp and paperproduction and supplies heat to production processes and premises at the factory. When the heat demandof the VVG-system exceeds the available recovered heat, heat from live steam is transferred. This projectaim at identifying measures with potential to reduce demand of live steam supply. The project started bymapping the entire VVG-system to identify which consumers are included and how it is connected. Thenthe consumers were studied and data was collected to determine their power and energy demands. Basedon the mapping and collected data, proposals for measures that have the potential to increase thermalenergy efficiency were noted which in turn can reduce the need for live steam supply. The measures havebeen focused on reducing the return temperature of the VVG-system and reducing the heat demand of thesystem. Reduced return temperatures are achieved by more efficient use of the existing heat flow. Thisleads to increased heat recovery potential which means that more excess heat can be utilised.The proposed measures that were identified as having potential to contribute to reduction of the returntemperatures of the VVG-system are as follow: • Utilising return flows with high flow rates and high temperatures to provide other consumers inVVG with heat. This allows the hot flow to be used instead of going directly into the return line. • Eliminate short circuits in the system where the supply line goes directly into the return line. Thesewere detected in the forms of three-way valves and flows through consumers that were not running. The proposed measures that have been identified as having the potential to contribute to reduction of theheating demand of the VVG are as follows: • Turning off flows passing through consumers that are not in use to reduce unnecessary temperaturedrops which will result in decreased power losses. • Preheating via residual flows at consumers where raw water tempered circuits is heated. As theraw water is cold during large parts of the year, a lot of heat can be saved by preheating it with aflow of lower energy quality than VVG. • Shut down the VVG flow through heat exchangers in the heat recovery system when the heatrecovery process not are running to avoid negative heat transfer. By implementing these measures, large improvements regarding the thermal efficiency of the VVG-system can be achieved at Holmen Paper Braviken. How much the return temperatures decrease and howmuch the heat recovery potential increases with the proposed measures has not been quantified during thisproject. However, the measures aimed at lowering the heat demand in the VVG-system can be quantifiedto contribute to an predicted energy saving of at least 2.8 GWh annually, but the investigations of themeasures indicates that significantly larger energy savings can be achieved. To ensure the potential of theproposed measures to contribute to the reduction of the demand for live steam supply, Holmen needs tocarry out further studies of the VVG system where this work is intended to form the basis for their furtherwork.
5

USING CASE-BASED REASONING FOR PREDICTING ENERGY USAGE

Bjurén, Johan January 2013 (has links)
In this study, the inability to in a future meet the electricity demand and the urge to change the consumption behavior considered. In a smart grid context there are several possible ways to do this. Means include ways to increase the consumer’s awareness, add energy storages or build smarter homes which can control the appliances. To be able to implement these, indications on how the future consumption will be could be useful. Therefore we look further into how a framework for short-term consumption predictions can be created using electricity consumption data in relation to external factors. To do this a literature study is made to see what kind of methods that are relevant and which qualities is interesting to look at in order to choose a good prediction method. Case Based Reasoning seemed to be able to be suitable method. This method was examined further and built using relational databases. After this the method was tested and evaluated using datasets and evaluation methods CV, MBE and MAPE, which have previously been used in the domain of consumption prediction. The result was compared to the results of the winning methods in the ASHRAE competition. The CBR method was expected to perform better than what it did, and still not as good as the winning methods from the ASHRAE competition. The result showed that the CBR method can be used as a predictor and has potential to make good energy consumption predictions. and there is room for improvement in future studies.
6

Visualization and simulation of idle truck energy usage : Prediction of battery discharge in a Volvo truck cab

Elvmarker, Simon January 2018 (has links)
Volvo Group Trucks Technology has found a need for a new way to present the battery status and electricity consumption of their on-board batteries in combustion engine trucks. Many battery related issues the drivers are facing could be prevented if a tool was developed that could assist with energy planning in an intuitive way. In many cases, the climate control system will constitute the bulk of the energy supplied by the battery. In addition, the climate system energy demand is dependent on both user settings and factors beyond the driver’s control. This work describes the process of developing a grey-box Simulink model able to predict the battery charge depletion rate based on signals already sampled by many Volvo truck versions. The resulting model is able to estimate the time remaining until the battery state of charge (SOC) is getting close to the crankability (starting engine) limit or risks causing battery damage. The settings of the climate system are shown to have great impact on the battery charge depletion rate. Predicting the time until the battery will reach a critical limit, and adjusting the climate system settings accordingly, can make the difference between the battery charge lasting overnight or not. A way to implement additional influences, such as sunlight, are discussed and recommendations are given.
7

Comparison of Energy Usage and Response Time for Web Frameworks

de Mander, Felicia, Gren, Wilhelm January 2023 (has links)
Background. Environmental sustainability and reducing energy consumption are important and relevant topics today. Energy consumption by data centres is constantly increasing. One factor that could be affecting this is what web frameworks are being used. Objectives. We wanted to investigate whether there is a difference in energy consumption depending on the selected web framework for an API web server. An improvement should not come with overhanging negative side effects. Therefore, energy usage was to be contrasted with response time. In addition, we wanted to see how the choice of response format affects these metrics. In the case of finding any considerable impact on energy usage, without compromising the response time, the goal was to communicate this in order to increase the awareness among software developers. Methods. A literature review was done in order to gather existing information on how to conduct an experiment measuring software energy consumption. We evaluated available tools for measuring consumed application energy. An experiment then compared four popular web frameworks in regard to both energy usage, and response time. Django, Express, Laravel, and Spring Boot were selected for the experiment. Metrics measured were energy usage and response time. The experiment was executed with three different amounts of concurrent requests vusers = {10, 100, 250}. Results. The literature study resulted in a selection of software tools for measuring software energy consumption to choose from. The tool perf was chosen for the experiment. In the experiment, the response format was shown to affect the response time, but not the energy consumption. Increasing the amount of concurrent users made for larger differences between frameworks, both regarding energy usage and response time. Express and Spring Boot show the best performance in both regards for all amounts of concurrent requests. Conclusions. Express and Spring Boot are the clear winners out of the four compared frameworks. Both in terms of energy usage and response time, they had the best results. Django is not a web framework to recommend if response time is of importance.
8

Powertrain Sizing and Energy Usage Adaptation Strategy for Plug-in Hybrid Electric Vehicles

Chanda, Soumendu 12 May 2008 (has links)
No description available.
9

High-Intensity Discharge Industrial Lighting Design Strategies for the Minimization of Energy Usage and Life-Cycle Cost

Flory, Isaac L. IV 13 October 2008 (has links)
Worldwide, the electrical energy consumed by artificial lighting is second only to the amount consumed by electric machinery. Of the energy usage attributed to lighting in North America, approximately fifteen percent is consumed by those lighting products that are classified as High-Intensity Discharge (HID). These lighting products, which are dominated by Metal-Halide and High-Pressure Sodium technologies, range in power levels from 35 to 2000 watts and are used in both indoor and outdoor lighting applications, one category of which is the illumination of industrial facilities. This dissertation reviews HID industrial lighting design techniques and presents two luminaire layout algorithms which were developed to provide acceptable lighting performance based upon the minimum number of required luminaires as determined by the lumen method, regardless of the aspect ratio of the target area. Through the development of lighting design software tools based upon the Zonal Cavity Method and these layout algorithms, models for the quantification of energy requirements, lighting project life-cycle costs, and environmental impacts associated with conventional industrial lighting installations are presented. The software tools, which were created to perform indoor HID lighting designs for the often encountered application of illuminating general rectangular areas with non-sloped ceilings utilizing either High-Bay or Low-Bay luminaires, provide projections of minimal lighting system costs, energy consumption, and environmental impact based upon lamp selection, ballast selection, luminaire selection and lighting system maintenance practices. Based upon several industrial lighting application scenarios, lighting designs are presented using both the new software tools and a commercially available lighting design software package. For the purpose of validating this research, analyses of both designs for each scenario are presented complete with results of illuminance simulations performed using the commercially available software. / Ph. D.
10

Vom Energiekonsum zur Energieeffizienz.

Wölfel, Sylvia 19 May 2016 (has links) (PDF)
Aus der Einführung: "Werbung für elektrische Haushaltsgroßgeräte spielte für die Durchsetzung und breite Akzeptanz von Elektrizität in den Privathaushalten der ersten Hälfte des 20. Jahrhunderts eine wichtige Rolle. Diese ist in zahlreichen Studien zur Technisierung des Haushaltes beschrieben worden.1 Im Zeichen einerbreitenwirksamen Ökologisierung von Politik und Alltag seit den 1970er Jahren entwickelte sich in den darauf folgenden Jahrzehnten eine neue Verbindung von Energieversorgung und Hausgerätekonsum. Standen bis 1970 Argumente der Arbeitserleichterung und Zeitersparnis durch elektrische Hausgeräte im Vordergrund von Werbebemühungen, so wurde dies in einem bis zur Gegenwart andauernden Prozess durch Hinweise auf einen besonders geringen Stromverbrauch von Kühlschränken oder Waschmaschinen ergänzt. Das Fortschrittsversprechen eines vollelektrischen Haushaltes sollte unter ökologischen Vorzeichen neu verhandelt werden und im Fortschrittsversprechen eines energieeffizienten Haushaltes seinen heutigen Ausdruck finden."

Page generated in 0.1616 seconds