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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.
511

Performance evaluation of a rooftop solar photovoltaic power plant in the Gävle Arenaby (Gävle, Sweden): Installation testing

Compadre Senar, David January 2018 (has links)
The current energy situation is taking a turn towards renewable energies, due to the new pacts to curb global warming. These agreements, together with governmental aid, are facilitating an escalation in the production and improvement of new energy systems and the price decrease due to a larger-scale production. Within these energy alternatives, solar energy is found, specifically the subject to be treated in this project is photovoltaic energy, due to its exponential growth in the last 10 years, new tools are being developed for its monitoring and modelling. Therefore, the main objective of this thesis is to develop a method  for installation testing of a PV-system. The method should give the installed nominal power of the system and show if the maximum power point trackers work as expected. A large PV-system was installed on the roof of Gävle Arenaby during 2017. A measurement system for monitoring of the power of the system and of the solar irradiance was installed. Different parameters have been taken into account for the adjustment of the model that vary the performance of the system. These factors are: the irradiance received, the module temperature and the angle of incidence. It has been concluded that the results obtained indicate a correct adjustment of the theoretical power against the real power, which means, a correct operation of the generated model. Besides, the expected power follows a linear trend, reaching the power set by the manufacturer for Standard Test Conditions. The results show that the monitored modules-strings fulffill the promised performance and the method for installation testing work as expected. The linear correlation between corrected power and irradiance means that the maximum power point tracker in the inverter works independent of the power.
512

Alternative energy supply study for a cottage in Vifors

Lumbier Fernandez, Mikel January 2018 (has links)
The present master thesis was done during the spring of 2018. A cottage located in Vifors is studied with regard to its heating requirements. At the time of the study, the house could not be inhabited the whole year because there was no tap hot water available and the space heating demand was covered by electricity. Thus, an alternative heating supply is required to be developed. As a strategic prerequisite, the solution should be achieved considering both solar thermal collectors and a heat pump.First, the characteristics of the building were collected/determined in order to obtain the total heating demand per month and hence annually. Parameters such as the U-values, roof orientation, room dimensions, ventilation rates and internal gains were required to configure the building model in the software IDA ICE 4.8. In addition, the amount of tap hot water required per year was determined as 17 m3 per year. Cold water at 5 °C had to be heated until 55 °C to obtain the tap hot water.Once the heating requirements were known, the most suitable solution was to use a combi system (solar thermal collectors and a heat pump). Solar energy could fulfil the demand in the summer and the heat pump provided energy in the winter. For a commercial model of the flat solar thermal collector (Vitosol 100-F) the solar system was sized according to the heating demand in the summer time. The maximum energy that could be obtained from the solar collectors in summer was calculated, the rest of the demand had to be fulfilled by a heat pump, model WPL-18 E.The achieved solution is compounded by the heat pump and 3 solar thermal collectors with a surface of 2.33 m2 each. The solar energy obtained is 1 843 kWh per year, which covers 9 % of the total annual heating demand (20 098 kWh). However, the 98 % of the heating demand during the summertime comes from the solar collectors. The investment cost is 113 900 SEK and the payback period is estimated in 8 years.
513

A Framework for Supporting Organizational Transition Processes Towards Sustainable Energy Systems

January 2011 (has links)
abstract: Economic development over the last century has driven a tripling of the world's population, a twenty-fold increase in fossil fuel consumption, and a tripling of traditional biomass consumption. The associated broad income and wealth inequities are retaining over 2 billion people in poverty. Adding to this, fossil fuel combustion is impacting the environment across spatial and temporal scales and the cost of energy is outpacing all other variable costs for most industries. With 60% of world energy delivered in 2008 consumed by the commercial and industrial sector, the fragmented and disparate energy-related decision making within organizations are largely responsible for the inefficient and impacting use of energy resources. The global transition towards sustainable development will require the collective efforts of national, regional, and local governments, institutions, the private sector, and a well-informed public. The leadership role in this transition could be provided by private and public sector organizations, by way of sustainability-oriented organizations, cultures, and infrastructure. The diversity in literature exemplifies the developing nature of sustainability science, with most sustainability assessment approaches and frameworks lacking transformational characteristics, tending to focus on analytical methods. In general, some shortfalls in sustainability assessment processes include lack of: * thorough stakeholder participation in systems and stakeholder mapping, * participatory envisioning of future sustainable states, * normative aggregation of results to provide an overall measure of sustainability, and * influence within strategic decision-making processes. Specific to energy sustainability assessments, while some authors aggregate results to provide overall sustainability scores, assessments have focused solely on energy supply scenarios, while including the deficits discussed above. This paper presents a framework for supporting organizational transition processes towards sustainable energy systems, using systems and stakeholder mapping, participatory envisioning, and sustainability assessment to prepare the development of transition strategies towards realizing long-term energy sustainability. The energy system at Arizona State University's Tempe campus (ASU) in 2008 was used as a baseline to evaluate the sustainability of the current system. From interviews and participatory workshops, energy system stakeholders provided information to map the current system and measure its performance. Utilizing operationalized principles of energy sustainability, stakeholders envisioned a future sustainable state of the energy system, and then developed strategies to begin transition of the current system to its potential future sustainable state. Key findings include stakeholders recognizing that the current energy system is unsustainable as measured against principles of energy sustainability and an envisioned future sustainable state of the energy system. Also, insufficient governmental stakeholder engagement upstream within the current system could lead to added risk as regulations affect energy supply. Energy demand behavior and consumption patterns are insufficiently understood by current stakeholders, limiting participation and accountability from consumers. In conclusion, although this research study focused on the Tempe campus, ASU could apply this process to other campuses thereby improving overall ASU energy system sustainability. Expanding stakeholder engagement upstream within the energy system and better understanding energy consumption behavior can also improve long-term energy sustainability. Finally, benchmarking ASU's performance against its peer universities could expand the current climate commitment of participants to broader sustainability goals. / Dissertation/Thesis / Ph.D. Sustainability 2011
514

UNDERSTANDING THE PRODUCTION BEHAVIOUR OF COMBINED HEAT AND POWER PLANTS : A mathematical programming approach

Bäckström, Mathias, Hellberg, Anton January 2018 (has links)
This thesis investigates how combined heat and power plants (CHP) produce electricity, with respect to several external factors including outdoor temperature and electricity prices. The purpose is to develop and evaluate a tool, with the aim to increase the understanding of CHP plants electricity production behaviour. This tool resulted in an optimisation model, developed in Python and using the CVXPY package. The objective of the model is to include a system of production units and optimise the production from these by minimising the production costs, while also considering technical constraints. Inspiration for the model was found from a literature review and from interviews with people working in the CHP sector, where the latter also provided historical production data used for validation. When comparing the modelled yearly electricity production with the historical data for the same year, it was found that the model deviated less than 10 percent for the two real district heating systems where the model was implemented. In conclusion, it is seen that the model behaves similar to the actual plants when looking at the electricity production; however, the behaviour of the model is slightly exaggerated with faster changes in the electricity production. Though, the results show that the developed model can be used to enhance the understanding of how CHP plants produce electricity.
515

Economic and Environmental Analysis of Excess Heat at Pulp Mills

Kullmann, Felix January 2018 (has links)
European industries have realized that a reduction of primary energy usage is not only a European requirement but can also be of great economic interest. Especially both energy and resource intensive industries like the pulp and paper industry will benefit. Industrial excess heat as a by-product of industrial processes needing energy has a great potential to be a key factor in reducing primary energy usage. Both excess heat utilization and heat integration are potential ways for Kraft pulp mills to increase their energy efficiency, to decrease their primary energy use and thus green-house gas emission, and to support the pulp and paper industry to achieve sustainability goals and meet EU regulations. This thesis examines the total excess heat potential in the Swedish Kraft pulp industry through pinch analysis and optimization on a modelled average Swedish Kraft pulp mill (FRAM). Different excess heat recovery technologies (EHRTs) are identified based on their applicability and are evaluated regarding their environmental and economic benefits for the Swedish pulp industry by using the energy price and carbon scenarios tool (ENPAC tool). An excess heat potential in the Swedish Kraft pulp mill industry of 2,03 TWh at 60°C, and 3,53 TWh at 25°C is found in this study. Heat delivery to the district heating network (DH), cooling delivery to the district cooling network (DC), electricity generation with a condensing turbine (CT), phase-change material engine (PCM) and organic Rankine cycle (ORC) are identified as suitable excess heat recovery technologies for Swedish Kraft pulp mills. A payback time calculation in this study found the condensing turbine as the EHRT to be of highest economic benefit in 2018 (less than 3 years). With predicted future energy prices of the years 2030, 2040 and 2050 all considered recovery technologies become economically feasible (payback time of less than 3 years). The CT and combinations of CT with DH and DC are furthermore the recovery technologies with the highest CO2 savings of 100.000 t/a in 2018. All in all, this study suggests investing in a CT, or combinations of it with DH and DC, to create the greatest economic and environmental benefits in 2018. With future price changes on the energy market and an uncertain future energy demand an investment in combinations of recovery technologies generating both heat, cooling and electricity is found to be the most sustainable choice.
516

[en] REABILITY-CENTERED MAINTENANCE - APPLICATION AND ADAPTATION TO ELECTRICAL POWER HIGH POWER SWITCHES / [pt] MANUTENÇÃO CENTRADA EM CONFIABILIDADE - AVALIAÇÃO DE SUA APLICABILIDADE E ADAPTAÇÃO A SUBESTAÇÕES DE ENERGIA ELÉTRICA

EDSON VIZZONI 27 October 2009 (has links)
[pt] A metodologia da Manutenção Centrada em Confiabilidade (MCC) reúne um conjunto de práticas que possibilita a criação, de modo sistemático e racional, de programas de manutenção focados na preservação das funções de sistemas dos quais as máquinas são componentes, o que tem levado a um crescente interesse em sua aplicação aos mais diversos contextos industriais. São apresentados aqui os fundamentos da metodologia e é feita uma aplicação de seus princípios à revisão do programa de manutenção preventiva atualmente adotado por FURNAS Centrais Elétricas S.A. para secionadores de alta tensão. Pretendeu-se, com isto, verificar a aplicabilidade e exercitar a adaptação da MCC a equipamentos de subestações elétricas, obtendo-se resultados que indicam não haver empecidos para a aplicação da metodologia a subestações de energia elétrica, mas apontam para a necessidade de se avaliar a eficiência de tal aplicação, através de uma análise e custos e benefícios. / [en] The methodology of Reliability-Centered Maintenance combine practices and theoretical finds from the Field of Reliability Engineering to design, in a systematic and rational way, maintenance programs focused on the functions of the systems instead of their components. This dissertation presents an application of the basic principles of RCM methodology to the revision of FURNAS Centrais Elétricas’s switchs’ maintenance program. The aim of this application is to verify the adaptation of RCM methodology to high voltage electrical equipaments. The results achieved suggests that RCM is a universally applicable methodology but management must be sure that benefits are greater than costs before to decide to apply this methodology to a particular installation.
517

Elektrifiering av transportsektorn i Göteborgs kommun : Nätintegrering av plug in-fordon och V2G-tjänster hos aggregator

Hjalmarsson, Johannes January 2018 (has links)
In 2015, the Paris Agreement was signed by almost 200 countries in order to define targets for future work within sustainability and to reduce further climate impact. Since then, the European Union has taken these targets in earnest and implemented purposeful legislation for all of its members. The Swedish government has introduced an even more ambitious climate policy framework in order to achieve as low national pollution levels as possible. By doing so, regional and local authorities have been forced to take action in order to meet the defined targets for 2030 and 2050. This implies that the Swedish transport sector is now facing a major challenge - to reduce its emissions of greenhouse gases by at least 70 % as of the level of 2010. A common opinion is that electric vehicles may play an important role in this task. To establish electric drivelines within the transport sector has been a worldwide vision for decades and it seems to be one of the most promising options today. Sweco has together with AB Volvo, Volvo Cars AB, Göteborg Energi, ABB Ltd and Vattenfall AB financed the official project PussEL. Mainly, the purpose of this project was to estimate the potential of a full electrification of the transport sector in a medium size city by 2030. For this project, it was of particular interest to use Gothenburg, Sweden, as a case study. It has been most relevant to consider the electrification of road transport, including both private and public transport as well as goods distribution. The analysis has resulted in a message to residents, businesses and politicians, that an extensive electrification is doable. However, the results also indicate that the distribution grid will require a significant extension. It will definitely require serious effort and will rely on the implementation of smart and controllable vehicle charging. Nevertheless, this might be just what it takes to become one of the world leading countries in sustainable transports. Secondly, the purpose of this thesis is also to clarify the potential of the local parking company to act as an aggregator for charging and discharging of electric vehicles. By considering local driving patterns, parking profiles in car parks, as well as prerequisites of the electricity markets, it has been possible to identify the technical potential. It has been of interest to investigate services including both smart charging (V1G) and vehicle-to-grid (V2G), in order to support an extensive electrification. The estimation has been done using available software from MathWorks: MATLAB. Previous research states that battery degradation from V2G services varies according to the depth of discharge (DOD). Thus, it is desired to utilize services that require a small DOD in order to minimize the reduction of battery lifetime. Considering the economic potential, this thesis examines several available services as an aggregator. Due to the variable capacity in each car parkin combination with the requirements set by the electricity markets, some services have been excluded at an early stage of the analysis. Although, besides economic profitability, a key to success is to keep the concept user-friendly. It must be kept in mind that car owners most likely will prioritize the freedom of mobility rather than leasing their vehicles as mobile batteries. As the Swedish lawyer Thomas Thorild once said: To think freely is great, but to think rightly is greater.
518

Laddinfrastruktur för elbilar vid stora trafikflöden och event : När uppstår problem och vilka är dess portabla lösningar?

Nilsson, Joacim January 2018 (has links)
The share of cars being powered by electricity is rising in Sweden. So far, this has seldom been causing queues at charging stations but if the rise continues as expected, it might potentially be a problem in the future. This thesis aims to shed light on when this might become a problem in a certain area and give example of a potential solution for that case. Three scenarios with different shares of cars being electric is analyzed with a simple model of a system with fast chargers for an area with a highly variable traffic flow. The arrival times to the system is derived from measured traffic flow and extrapolated up until 2030 and a charging time is set based on assumed travel behavior. A comparison is made between the expected electricity consumption using this approach and actual data from a fast charging station. The comparison indicates that electric cars are not being used for the winter time cross-country trips analyzed here in the same extent as conventional cars. The potential to keep the number of stationary fast chargers down using a portable solution with Li-ion battery storage with and without attached production of electricity for situations with a higher than normal charging demand is then investigated. A containerized Li-ion battery solution of 760 kWh has the potential to replace two 50 kW fast chargers in the studied case.
519

Cradle-to-gate life-cycle assessment of future materials for commercial lithium-ion batteries : Raw Materials issues

Martinez Pancorbo, Pablo January 2018 (has links)
Current private transportation remains very harmful for the environment, especially the non-electric vehicles. This report proposes five novel type of nanomaterials-based Li-ion batteries to improve substantially the electric vehicle battery properties along with a substantial reduction of the environmental impact of its commercial counterparts. To address the problem, a cradle-to-gate life-cycle assessment has been performed in which the biggest emphasis has been focused on the energy and materials inputs and outputs during the raw materials extraction. We show how the analyzed Ni-doped graphene battery and Fe3O4-based Cu battery are the most environmentally friendly, stable, reliable and improved batteries among the five cases of study. These results can open new horizons for future advances in the implantation of an electromobility transportation. / <p>I presented my work via Skype while sharing the screen.</p>
520

Elbilar på Lidingö : Påverkan på det regionala elnätet / Electric vehicles on Lidingo : Effects on the regional power grid

Andersson, Viktoria January 2018 (has links)
This thesis aims towards increasing the understanding of how the growing number of electric cars is going to affect the regional power grid of Stockholm. The results are meant to aid in long term planning of maintenance and development of the regional power grid. Three possible scenarios are presented for the development of electric cars on Lidingo until the year 2040. The number of electric cars, maximum load and load profiles are calculated and analyzed for each scenario. Possible measures of value for the DSO Ellevio are then presented. By the year 2040 it is likely that at least one fourth of cars are electric. The maximum power loads from the charging of electric cars will coincide with already existing power peaks during early evening. Loads from charging of electric car will cause a significant contribution to the loads of the regional power grid. If international, national and local climate goals are to be fulfilled the loads would be even larger, though that scenario is deemed unlikely. It is concluded that extensive measures in the regional power grid of Lidingo are needed in order to handle the new maximum loads. It is suggested that Ellevio should start planning for upgrading components, install energy storages and work for load shifting in order to handle the higher loads.

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