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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.
441

Energy Saving Curtain : ENERGY INVENTORY AND CONSERVATION POSSIBILITIES

Zou, Fan January 2008 (has links)
This paper presents the energy saving curtains, in order to make the consumers be more aware of the energy efficiency of the energy saving curtains, the paper gave related analysis and conclusions. The work was performed by using the Parasol Program, developed by Lunds University, Sweden. The Program is used for quantifying the influence of window size, glass type, textile type, wall thermal insulation and sun shading on annual energy use and indoor thermal comfort. The results which are obtained from the calculations are applicable to similar climatic and environment conditions. Calculations were performed to investigate the potential for using sunshade devices to reduce annual energy demand for cooling and heating. Different materials and dimensions of the energy saving curtain are used as variables in the analysis. The results indicated that for the current climatic conditions and other related factors, the total reduction rate of the annual energy consumption of office used buildings in Stockholm is estimated generally 20% -30% lower comparing to those buildings without energy saving curtain system. That means at least 20% of energy cost can be saved by the energy saving curtain system.
442

A new integrated procedure for energy audits and analyses of buildings / M.F. Geyser

Geyser, Martinus Fredrik January 2003 (has links)
A rapid growth in the national electricity demand is placing an ever-increasing demand on the national electricity supply utility, Eskom. Projections show that the load demand in South Africa may exceed the installed capacity by as early as 2007. This is mainly due to the increase in demand in the residential sector as a result of the electrification of rural and previously disadvantaged communities. However, the industrial and commercial sectors also have a role in this increase. In an attempt to reduce the demand for electricity Eskom has adopted its Demand Side Management (DSM) initiative. This initiative is aimed at lowering the electricity demand in peak times through energy efficiency (EE) or load shift, out of peak demand times. Eskom is implementing the DSM strategy by financing Energy Service Companies (ESCOs) to reduce the demand load of major electricity end-users during peak times. Buildings consume a large percentage of the total energy supply in the world. Most of the energy consumed in buildings is used by the heating, ventilation and air-conditioning (HVAC) systems, as well as lighting. However, a large potential for energy savings exists in buildings. Studies have shown that up to 70% of the electricity consumption of a building can be saved through retrofit studies. However, to capitalise on these opportunities, the ESCOs require tools and procedures that would enable them to accomplish energy savings studies quickly and efficiently. It should be a holistic approach to the typical ESCO building audit. A study of current available software programs showed the lack of holistic tools aimed specifically at retrofit audits, and therefore also the need for such a program. The building simulation program most suited to the retrofit study was chosen and it was used in a retrofit audit. By emulating a retrofit audit with this software, its performance in the field, both positive and negative, could be established. With the experience gained from the retrofit study, as well as input from ESCOs in the industry, a need for such a retrofit tool was established. The simulation program that was tested in the retrofit study is the tool Quickcontrol, as well as the newer version of the program, entitled QEC. The case study showed that even though these packages are well suited to ESCO work, they have certain drawbacks in view of the holistic project approach. The ESCOs require a simple, fast, and integrated procedure for energy audits. This procedure should be embodied in a software program. This study proposes a new integrated procedure for energy audits and the analyses of buildings, in the form of a software tool. This new tool is geared towards the ESCO building audit, in both South A6ica and internationally. It is designed to enable a diplomate engineer to accomplish a building energy and retrofit analysis in two weeks, leading the user through all the main project steps, from data acquisition to writing of the final project report. This is a significant improvement, since it normally takes 50 man-days for an experienced and trained engineering team to complete a full building audit. This tool was used in a case study to test its validity and accuracy. It was found that certain situations would arise in which the criteria that were set for the program would not be adequate. The results from the case study were favourable and satisfied the criteria that were set for the procedure. / Thesis (Ph.D. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2004.
443

An Energy-Efficient Reservation Framework for Large-Scale Distributed Systems

Orgerie, Anne-Cécile 27 September 2011 (has links) (PDF)
Over the past few years, the energy consumption of Information and Communication Technologies (ICT) has become a major issue. Nowadays, ICT accounts for 2% of the global CO2 emissions, an amount similar to that produced by the aviation industry. Large-scale distributed systems (e.g. Grids, Clouds and high-performance networks) are often heavy electricity consumers because -- for high-availability requirements -- their resources are always powered on even when they are not in use. Reservation-based systems guarantee quality of service, allow for respect of user constraints and enable fine-grained resource management. For these reasons, we propose an energy-efficient reservation framework to reduce the electric consumption of distributed systems and dedicated networks. The framework, called ERIDIS, is adapted to three different systems: data centers and grids, cloud environments and dedicated wired networks. By validating each derived infrastructure, we show that significant amounts of energy can be saved using ERIDIS in current and future large-scale distributed systems.
444

An Integrated Framework for Wireless Sensor Network Management

Karim, Lutful 19 June 2012 (has links)
Wireless Sensor Networks (WSNs) have significant potential in many application domains, and are poised for growth in many markets ranging from agriculture and animal welfare to home and office automation. Although sensor network deployments have only begun to appear, the industry still awaits the maturing of this technology to realize its full benefits. The main constraints to large scale commercial adoption of sensor networks are the lack of available network management and control tools for determining the degree of data aggregation prior to transforming it into useful information, localizing the sensors accurately so that timely emergency actions can be taken at exact location, and scheduling data packets so that data are sent based on their priority and fairness. Moreover, due to the limited communication range of sensors, a large geographical area cannot be covered, which limits sensors application domain. Thus, we investigate a scalable and flexible WSN architecture that relies on multi-modal nodes equipped with IEEE 802.15.4 and IEEE 802.11 in order to use a Wi-Fi overlay as a seamless gateway to the Internet through WiMAX networks. We focus on network management approaches such as sensors localization, data scheduling, routing, and data aggregation for the WSN plane of this large scale multimodal network architecture and find that most existing approaches are not scalable, energy efficient, and fault tolerant. Thus, we introduce an efficient approach for each of localization, data scheduling, routing, and data aggregation; and compare the performance of proposed approaches with existing ones in terms of network energy consumptions, localization error, end-to-end data transmission delay and packet delivery ratio. Simulation results, theoretical and statistical analysis show that each of these approaches outperforms the existing approaches. To the best of our knowledge, no integrated network management solution comprising efficient localization, data scheduling, routing, and data aggregation approaches exists in the literature for a large scale WSN. Hence, we e±ciently integrate all network management components so that it can be used as a single network management solution for a large scale WSN, perform experimentations to evaluate the performance of the proposed framework, and validate the results through statistical analysis. Experimental results show that our proposed framework outperforms existing approaches in terms of localization energy consumptions, localization accuracy, network energy consumptions and end-to-end data transmission delay.
445

Performance Indicator Analysis as a Basis for Process Optimization and Energy Efficiency in Municipal Wastewater Treatment Plants / Nyckeltalsanalys som underlag för processoptimering och energieffektivisering i kommunala avloppsvattenreningsverk

Wennerholm, Elin January 2014 (has links)
The aim of this Master Thesis was to calculate and visualize performance indicators for the secondary treatment step in municipal wastewater treatment plants. Performance indicators are a valuable tool to communicate process conditions and energy efficiency to both management teams and operators of the plant. Performance indicators should be as few as possible, clearly defined, easily measurable, verifiable and easy to understand. Performance indicators have been calculated based on data from existing wastewater treatment plants and qualified estimates when insufficient data was available. These performance indicators were then evaluated and narrowed down to a few key indicators, related to process performance and energy usage. Performance indicators for the secondary treatment step were calculated for four municipal wastewater treatment plants operating three different process configurations of the activated-sludge technology; Sternö wastewater treatment plant (Sweden) using a conventional activated-sludge technology, Ronneby wastewater treatment plant (Sweden) using a ring-shaped activated-sludge technology called oxidation ditch, Headingley wastewater treatment plant (Canada) and Kimmswick wastewater treatment plant (USA), both of which use sequencing batch reactor (SBR) activated-sludge technology. Literature reviews, interviews and process data formed the basis of the Master Thesis. The secondary treatment was studied in all the wastewater treatment plants. Performance indicators were calculated, to the extent it was possible, for this step in the treatment process. The results showed that all the wastewater treatments plants, studied in this master thesis, were well below regulatory requirements of effluent concentrations of organic matter and nutrients. This gap between legislated requirements and performance provides an opportunity for improving energy efficiency and maintaining discharge requirements. The removal of organic matter was consistently high at all wastewater treatment plants studied but the removal of nitrogen was slightly lower during the colder months. The results further showed that the discharge of nitrogen from wastewater treatment plants is the largest stress on the recipient. Data regarding the energy usage was almost nonexistent and energy for aeration was therefore calculated when possible since it is aeration that accounts for the largest fraction of energy usage in a wastewater treatment plant. Sternö wastewater-treatment plant proved to be more energy efficient than Rustorp wastewater treatment plant.
446

Warm homes, greener living: reducing energy poverty in Daniel McIntyre and St. Matthews through energy retrofits

Schulz, Kari 09 January 2012 (has links)
This research examines energy poverty in the Daniel McIntyre and St. Matthews (DMSM) neighbourhoods in the city of Winnipeg. Energy poverty, defined as households spending more than 6% of their income on energy expenditures, affects as many as 50% of households in DMSM. Energy poverty can be alleviated through energy retrofits for dwellings such as weather stripping; increasing insulation in exterior walls, the attic and basement; and installing a high-efficiency furnace. The recommendations include: establishing consistent housing and energy efficiency policies; increasing the flexibility of utility on-bill financing; levying the necessary capital for energy retrofits through municipal financing mechanisms; increasing the knowledge and capacity of local residents; increasing the knowledge and capacity of local contractors for sustainable design and construction; creating a provincial strategy to increase the energy efficiency of social housing; developing low-income energy efficiency programs for rental properties; and increasing access to renewable energy sources.
447

Harnessing Data Parallel Hardware for Server Workloads

Agrawal, Sandeep R. January 2015 (has links)
<p>Trends in increasing web traffic demand an increase in server throughput while preserving energy efficiency and total cost of ownership. Present work in optimizing data center efficiency primarily focuses on using general purpose processors, however these might not be the most efficient platforms for server workloads. Data parallel hardware achieves high energy efficiency by amortizing instruction costs across multiple data streams, and high throughput by enabling massive parallelism across independent threads. These benefits are considered traditionally applicable to scientific workloads, and common server tasks like page serving or search are considered unsuitable for a data parallel execution model.</p><p>Our work builds on the observation that server workload execution patterns are not completely unique across multiple requests. For a high enough arrival rate, a server has the opportunity to launch cohorts of similar requests on data parallel hardware, improving server performance and power/energy efficiency. We present a framework---called Rhythm---for high throughput servers that can exploit similarity across requests to improve server performance and power/energy efficiency by launching data parallel executions for request cohorts. An implementation of the SPECWeb Banking workload using Rhythm on NVIDIA GPUs provides a basis for evaluation. </p><p>Similarity search is another ubiquitous server workload that involves identifying the nearest neighbors to a given query across a large number of points. We explore the performance, power and dollar benefits of using accelerators to perform similarity search for query cohorts in very high dimensions under tight deadlines, and demonstrate an implementation on GPUs that searches across a corpus of billions of documents and is significantly cheaper than commercial deployments. We show that with software and system modifications, data parallel designs can greatly outperform common task parallel implementations.</p> / Dissertation
448

Investments, system dynamics, energy management and policy : a solution to the metric problem of bottom-up supply curves

Levihn, Fabian January 2015 (has links)
Today, issues such as climate change and increased competition for scarce resources puts pressure on society and firms to transform. Change is not easily managed though, especially not when relating to production or consumption of energy carriers such as district heating or electric power. These systems do not only have strong dynamics internally, but dynamics between multiple technological systems must sometimes be considered to effectively manage response and strategies in relation to change. During the early 1980s, an optimisation model founded on an expert-based approach was developed based on the partial equilibrium model to enable the evaluation of different actions to reach a target. This model — often referred to as marginal abatement cost curve (MACC) or conservation supply curve (CSC) — is used by academia, industry and policymakers globally. The model is applied for causes such as energy conservation and waste management, but also within the climate change context for optimising CO2 reductions and governmental policy. In this context, the model is used by actors such as the Intergovernmental Panel on Climate Change (IPCC), International Energy Agency (IEA) and World Bank, and by the consultancy firm McKinsey &amp; Company, who use it extensively in different analysis. This model has many drawbacks in relation to managing interdependencies between different options, but more specifically the metric used for ranking options with a negative marginal cost has a design flaw leading to biased results. As a solution Pareto optimisation has been suggested, but is problematic given the dynamics within and between energy systems. The purpose of this compilation dissertation is to improve the ability for industry and policymakers to effectively manage change and reach set targets. In particular it develops our knowledge of how to account for option interdependency within and between technological systems. Furthermore, the ranking problem relating to expert-based least cost integrated planning is addressed. This dissertation also provides policy and managerial implications relating to the issues of energy conservation, CO2 abatement, and SOx and NOx reduction in relation to the district heating system in Stockholm. Implications are also provided for the interaction with other systems such as the Nordic electric power system. / Klimatfrågan och konkurrens om knappa resurser medför ett förändringstryck på nationer och företag. Att hantera förändringar har aldrig varit enkelt, vilket är tydligt bland företag inom energisektorn såsom el och fjärrvärmeproducenter. Energisystemen dessa företag är del av har stark intern dynamik, men även dynamik mellan olika energisystem är vanligt. Detta måste tas i beaktande när strategier och planer för att hantera förändring utformas. Under början av 1980-talet skapades en optimeringsmodell baserad på den nationalekonomiska jämviktsmodellen för att kunna utvärdera olika specifika möjligheter att nå ett mål, t.ex. energibesparingar. Denna modell, som idag ofta benämns MACC (Marginal Abatement Cost Curves) eller CSC (Concervation Supply Curves), används idag av akademin, industrin och myndigheter inom områden så som energibesparingar, minskade CO2-utsläpp, sophantering och design av ekonomiska policyinstrument. De icke-akademiska användarna inkluderar FNs klimatorgan IPCC, IEA och Världsbanken. Även konsultfirman McKinsey&amp;Company använder modellen regelbundet i olika studier. Tyvärr har modellen många begräsningar när det kommer till att hantera dynamiker mellan de specifika åtgärder som identifierats för att nå ett mål. Den allvarligast begränsningen utgörs dock av ett optimeringsfel som leder till felaktiga slutsatser om prioriteringen mellan de åtgärder som har en negativ marginalkostnad. Som en lösning på detta problem har pareto-optimering föreslagits, vilket denna avhandling dock visar är problematiskt på grund av de dynamiker som finns inom och mellan energisystem. Det övergripande syftet med denna avhandling är att förbättra möjligheten att hantera förändringar och nå uppsatta mål. Specifikt diskuteras hur beroenden mellan olika åtgärder för att nå det satta målet kan hanteras. Avhandlingen adresser även problemet att prioritera mellan åtgärder med negativ marginalkostnad. Utöver detta bidrar avhandlingen med praktiska implikationer för politiker, myndigheter och företag involverade i fjärrvärmeproduktion i Stockholm. Slutsatser dras kring energibesparingar och minskade utsläpp av CO2, SOx och NOx. Praktiska implikationer ges även för hur system som detta fjärrvärmesystem samverkar och interagerar med det nordiska elsystemet. / <p>QC 20150414</p> / Investments in energy efficiency and climate change abatement: revising marginal cost curves as an optimization model
449

Energieffektivisering i kulturhistoriskt värdefull bebyggelse : Ett förslag på modell för utvärdering av energieffektiviserande åtgärder / Energy efficiency in historically valuable buildings : A proposed model for evaluation of actions regarding energy efficiency

Lindström, Ellen, Ideskog, Jakob January 2014 (has links)
Sveriges riksdag har beslutat att energianvändningen i bebyggelsen måste minskas. Detta gäller även den befintliga bebyggelsen till vilken den kulturhistoriskt värdefulla bebyggelsen hör. Vid energieffektivisering av kulturhistoriskt värdefull bebyggelse upplever ofta förvaltare att processen att välja energieffektiviserande åtgärd tar för lång tid. Detta beror på att det saknas ett rationellt sätt att jämföra olika åtgärders konsekvenser. Antikvarier har ofta en motsatt uppfattning och upplever att förvaltare många gånger ser mer till åtgärdens besparingspotential istället för dess påverkan på de kulturhistoriska värdena.  Syftet med examensarbetet är att göra jämförelsen av energieffektiviserande åtgärder i kulturhistoriskt värdefull bebyggelse mer överskådlig för förvaltare. Genom litteraturstudier, dokumentanalyser, intervjuer och fallstudie besvarades följande frågeställningar: - Vilka kulturhistoriska faktorer bör beaktas vid energieffektivisering i kultur­historiskt värdefull bebyggelse? - Hur kan energibesparande åtgärder utvärderas i en modell där hänsyn tas till energibesparingspotential och de kulturhistoriska faktorer som framkommit i första frågeställningen? - Hur används modellen från andra frågeställningen vid jämförelse av möjliga åtgärder i en befintlig byggnad? Kulturhistoriska faktorer identifierades och utgjorde grunden till den modell som sedan togs fram. Till respektive faktor kopplades kriterier med olika poängnivåer för utvärdering. En matris togs fram för att åskådliggöra utvärderingens resultat. För att visa på modellens funktion genomfördes en fallstudie där modellen användes på en befintlig byggnad. För att möjliggöra utvärdering av valda åtgärder genomfördes både observationer och beräkningar. Fallstudien genomfördes på Länsresidenset i Jönköping.  Resultatet av studien visar att reversibilitet, långsiktighet, påverkan på synintryck och upplevelse och påverkan på kulturhistoriskt värdefulla byggnadsdelar och detaljer är viktiga kultur­­­­­historiska faktorer att beakta vid energieffektivisering i kulturhistoriskt värdefull bebyggelse. Kriterier för utvärdering bör formuleras noggrant och generellt för att passa in på varje typ av åtgärd samt för att undvika subjektiv bedömning. För att erhålla en överskådlig jämförelse bör färger användas vid gradering. Dessutom bör viktning användas för att kunna anpassa prioriterings­graden av varje enskild faktor i en specifik byggnad. Efter utvärdering av åtgärder i en specifik byggnad bör specialister inom olika områden konsulteras för slutligt val av åtgärd. / The Swedish Parliament has decided that the energy consumption in buildings must be reduced. This also applies to existing buildings to which the historically valuable buildings belong. When improving energy efficiency in historically valuable buildings managers often experience that the process of choosing acts takes too long time because there is no rational way to compare different consequences of the acts. Antiquarians on the other hand, often have a different opinion and experiencing that managers often look more to the potential of savings rather than the impact on the cultural value. The aim of the essay was to make the comparison of energy efficiency acts in the historically valuable buildings more transparent for managers. Through literature study, document analysis, interviews and case study the following questions has been answered: - What cultural-historical factors should be taken into account at improving energy efficiency in the historically valuable buildings? - How can energy-saving acts be evaluated in a model which takes into account the potential of energy saving and the cultural factors identified in question 1? - How should the model from question 2 be used for comparisons of possible actions in an existing building? Cultural-historical factors were identified and formed the basis for the model that was developed. For each factor criteria was connected with different point levels for evaluation. A matrix was developed to visualize the result. To demonstrate the function of the model a case study was carried out where the model was used in an existing building. To enable evaluation of selected acts both observations and calculations were performed. The case study was performed at Länsresidenset in Jönköping. The results of the study shows that Reversibility, Long-sightedness, Impact on visual impressions and experience, Impact on historically valuable parts and details, and Other is important cultural factors to consider when improving energy efficiency in historically valuable buildings. Criteria for evaluation should be formulated carefully and generally to fit each type of action and to avoid subjective assessment. To obtain a perspicuous comparison colors should be used for grading. Furthermore, weighting should be used to adjust the priority level of each individual factor in a specific building. After evaluation of actions in a specific building has been done specialists in various fields should be consulted for final selection of acts.
450

Using uncertainty and sensitivity analysis to inform the design of net-zero energy vaccine warehouses

Pudleiner, David Burl 27 August 2014 (has links)
The vaccine cold chain is an integral part of the process of storing and distributing vaccines prior to administration. A key component of this cold chain for developing countries is the primary vaccine storage warehouse. As the starting point for the distribution of vaccines throughout the country, these buildings have a significant amount of refrigerated space and therefore consume large amounts of energy. Therefore, this thesis focuses on analyzing the relative importance of parameters for the design of an energy efficient primary vaccine storage warehouse with the end goal of achieving Net-Zero Energy operation. A total of 31 architectural design parameters, such as roof insulation U-Value and external wall thermal mass, along with 14 building control parameters, including evaporator coil defrost termination and thermostat set points, are examined. The analysis is conducted across five locations in the developing world with significant variations in climate conditions: Buenos Aires, Argentina; Tunis, Tunisia; Asuncion, Paraguay; Mombasa, Kenya; and Bangkok, Thailand. Variations in the parameters are examined through the implementation of a Monte Carlo-based global uncertainty and sensitivity analysis to a case study building layout. A regression-based sensitivity analysis is used to analyze both the main effects of each parameter as well as the interactions between parameter pairs. The results of this research indicate that for all climates examined, the building control parameters have a larger relative importance than the architectural design parameters in determining the warehouse energy consumption. This is due to the dominance of the most influential building control parameter examined, the Chilled Storage evaporator fan control strategy. The importance of building control parameters across all climates examined emphasizes the need for an integrated design method to ensure the delivery of an energy efficient primary vaccine warehouse.

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