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1972 Uppsatser om Flow efficiency - Sida 25 av 132
Smart Control : En reaktion på EU:s ekodesignkrav
The purpose of this thesis is to assist the Swedish energy company NIBE Energy Systems in their studies of adaptive regulation applicable to electrical water heaters. Due to coming energy classifications of these appliances in the European Union, NIBE Energy Systems needs to use adaptive regulation, called Smart Control, to keep their products in the best possible energy class and remain competitive to the market. By using this Smart Control regulation a 2-3 % improve-ment of efficiency can be credited the system. This is a small number, but heavily needed, since the energy classes are based on the idea that the European Union is provided with electricity from coal condensate power resulting in a 40 % maximum efficiency. Furthermore, doing noth-ing will result in some water heaters not being approved to use on the market from 2015 due to low efficiency.
Development of Liquid Cooling for PCs
In recent years, existing solutions for cooling personal computer CPUs have been supplemented by a new product category, factory sealed water cooling loops. These systems, consisting of a water block with an integrated pump, a fan and a radiator, perform well compared to the air cooling solutions but are less effective than larger, custom-built water cooling systems.This project aims to explore the most important aspects of a factory sealed system and to identify possible cost-effective enhancements of the performance.The most significant differences between the different groups of water cooling loops are the block design and the pumping power. The performance of both categories is also largely dependent on the fan power, but increasing fan power has a large negative impact on the noise level.Both radiator size and fan model choice appear, in tests, to be relatively unimportant, presuming that the noise level is kept constant. The position and direction of the fan, however, has significant impact on both the temperature and the sound level.Water blocks can be designed in several different ways, both regarding the heatsink design and the flow direction. In simulation, flow with the inlet centered above the heatsink result in considerably lower pressure drop and slightly higher temperatures than flow through the block, for heatsinks with fin arrays.Creating a competitive product in this product segment certainly seems possible, as there are performance-increasing changes to be made that seemingly has little impact on the production cost.
Föroreningsspridning via ledningsgravar : en fältstudie på Köpmanholmens industriområde
Sewer trenches usually contain material with a higher hydraulic conductivity then the adjacent soil. Thus they can serve as paths of preferential flow in a polluted area. Wastewater from factories can also leak from wastewater pipes and pollute the soil in the sewer trenches.The purpose of this project was to investigate pollutions in sewer trenches and in sewer pipes in the industrial area of Köpmanholmen, 20 km south of Örnsköldsvik in the north of Sweden. To make an estimation concerning the potential of transport of pollutions in sewer trenches, hydrological calculations were performed.Leakage to any greater extent did not seem to be a problem in the area. This is the case both for the concrete and the wooden pipes that have served as factory wastewater pipes.
Fluidrörelse- och värmetransportsmodellering i götugn
The purpose of this thesis for Sapa Heat Transfer is to examine a furnace in which aluminium is pre-heated before hot rolling. The project is modeled in a computer environment in which the air flow in the furnace and the heat transfer to the aluminium solids are included. The computer environment and its governing equations, as well as boundary conditions and generalizations, are presented and explained.The simulations are based on two models. The first model has an asymmetric solid placement, which is how it looks in today's ovens. It is validated against collected data.
Energieffektivisering i flerbostadshus : En analys av ägarformens påverkan på arbetsprocessoch resultat
In Sweden the residential and commercial sector is a major user of energy, why the Swedish government has set a specific goal to half the energy usage in buildings by 2050, compared to 1995. The Swedish Energy Agency has therefore started the campaign ?Halvera Mera? to encourage demonstration projects that will show how to renovate in an energy efficient way, and in doing so prove that it is possible to reduce a building?s energy usage by half and still make a profit. These projects are intended to serve as good examples and give inspiration to residential owners to perform energy efficient renovations. To make sure that these projects serve their purpose, it is important to know what will inspire and what will impede a residential owner to invest in energy efficiency improvements.
Optimering av driftläggningar i Fortums nät
Future emission legislation puts great emphasis on increasing the efficiency of the engine, thereby reducing fuel consumption. The tribological contact between cylinder liner and piston ring is where an great amount of energy is lost due to friction, and by reducing these losses an reduction in fuel consumption can be achieved.The aim of this thesis was to evaluate the tested piston ring coatings against a plasma sprayed cylinder liner and rank these combinations of materials for friction and wear resistance. The coatings that were tested was Cr + Al2O3, (Al,Cr)N, two types of CrN and WC / C.The experimental tests were performed with a so-called pin-plate, where used oil with addition of an acidic mixture of sulfuric and nitric acid to mimic the acidic condensate formed when exhausts recirculate, were added with a continuous flow. The results were then analyzed by weighing, studies by optical microscopy and scanning electron microscopy (SEM) and profile measurements.The results from each material combination were that the plasma coated cylinder liner wears too aggressively in order to yield a ranking of the piston ring coatings based on the parameters of friction and wear resistance. It is therefore proposed that an alternative coating on the cylinder liner should be developed, lacking the large abrasive wear on piston rings and that can withstand the corrosive environment resulting in engines equipped with EGR.
Informationsdesign i hemmets hjärta : Struktur och ordning i kök för personer med neuropsykiatriskt funktionshinder
Business Process Modelling Notation (BPMN) is a way to graphically draw a diagram of a business process. A BPMN diagram consists of several so-called flow objects. These are interconnected in the graph through sequence flows. BPMN models are merely graphical representations of business process and there is a need to simulate these diagrams for different purposes. The simulation that now is available for BPMN is that the model is evaluated by checking if it is correct.
Energieffektiv torkning av kläder : en studie av torktumlare med varm- respektive kallvattenanslutning
Tumble dryers and drying cabinets have to a large extent replaced the traditional way of drying clothes outdoors. They are faster, more convenient, require less space and can be operated regardless of weather conditions. This replacement has significantly increased residential energy consumption, due to the fact that tumbles dryers consume large amounts of electrical energy. In the USA 9 % of the households electric energy is consumed when drying clothes. Over 4 million tumble dryers are sold in Europe each year and 20 % of the residential electricity consumption in Sweden is used drying and washing clothes.
Övertoner i elnät vid Skellefteå lasarett : Harmonics in power grids at Skellefteå Hospital
The goal of this paper is to find out how solar cells can improve energy efficiency on-board M/S Sydfart. The paper is based on a number of energy measurements on board the M/S Sydfart. The solar surface is calculated by measuring the available space for installing solar panels. Global radiation data is taken from STRÅNG's database, the data is then used to calculate the theoretical power produced by the solar cells. Energy efficiency is analysed in two ways.
En usabilityutvärdering av Umeå Universitetsbiblioteks OPAC
This is a heuristic evaluation of Umeå university library?s Online Public Access Catalog (OPAC). It makes use of four of Nielsen?s ten heuristics, flexibility and efficiency to use, match between the system and real world, visibility of system status, and aesthetic and minimalist design. The evaluation was done by having 3 evaluators inspect the interface individually, as per Nielsen?s (1990) recommendation of 3-5 evaluators.
Utveckling av 22 : -en motkolvs HCCI motor
Environment friendly transports are one of the main topics in the industry and society today.Shell organizes an annual university competition called Shell Eco Marathon. The goal is to buildthe car that consumes the least fuel during a race. KTH participated for the first time in 2006.The engine for this competition, DoubleTwo, has been developed within the school. Theprinciple is a two stroke counter piston HCCI engine with variable compression ratio. HCCIstands for homogenous charge compression ignition.
ISIT-modellen : Vägledning för att realisera en verksamhets informationssäkerhetsmål
The ISO standard ISO/IEC 17799/SS-627799-2 is a guidance for organizations to realize their information security goals. In spite of this standard, studies show flaws regarding information security in organizations. In particular flaws regarding overall view, knowledge and clear roles and responsibilities have been observed. The ISIT (Information Security Integrated Three level) model and its guidelines, developed in this thesis, help organizations to identify the required processes and procedures as well as the logical process flow. The thesis is based on theoretical studies and a case study within a multinational company.
Passande svårighet? : Spelares uppmärksammande av och attityder till dynamisk svårighetsjustering
Syftet med detta arbete är att undersöka hur dynamisk svårighetsjustering påverkar hur spelare värderar ett spels svårighet, presterar under en spelsession och huruvida de kan upptäcka ett system för sådan justering samt identifiera hur det fungerar. Arbetet vilar främst på Robin Hunickes arbete kring dynamisk svårighetsjustering men vidrör även koncept som svårighet, flow och olika typer av svårighetsjustering. För att undersöka huruvida system för dynamisk svårighetsjustering påverkar spelande har ett plattformsspel utvecklats och speltestats i två versioner av en handfull respondenter, en version som justerar svårigheten i spelet dynamiskt och en som balanserats för hand. Resultatet från dessa speltester ger inga direkta stöd för att dynamisk svårighetsjustering får spelare att prestera bättre och tyder på att spelare vid en första spelomgång har svårt att identifiera system för dynamisk svårighetsjustering. Resultatet visar dock även på att mer undersökningar kan behövas på ämnet i framtiden..
Struktur och styrning med balanced scorecard som styrverktyg : En studie inom Västra Götalandsregionen
BackgroundThere are different organizational structures and control and it has been proved difficult to find a combination between these that leads to goal congruence and improved efficiency. An organization can be structured according to hierarchical levels and the decision making can be either centralized or decentralized. Organizational control can be classified according to the amount of rules and balanced scorecard can be used to weld together the structure with the control.PurposeThe purpose is to create an understanding of how two types of structures and control in an organization appears and also to investigate how these differ from one another concerning the balanced scorecard as a control system. We will also investigate how the variables goal congruence and efficiency are affected by the implementation of the balanced scorecard.MethodTo answer the purpose of this thesis we have mainly used the qualitative method since we have studied two organizations thoroughly through interviews on different levels of the organization. The study also has some quantitative elements since we wanted to get a more truthful picture of the organizations.
Faktorer som påverkar effektivitet och kvalitet vid outsourcing
With an IT outsourcing project there are many factors affecting how efficiency andquality develop in the outsourced activity. The Purpose of this study is to identifythese factors through a case study in a global company that is dissatisfied with theefficiency and quality of their outsourced helpdesk. For data collection methodsinterviews and observations were used. Interviews were conducted with people fromdifferent parts of the company in three different countries, all somehow involved inthe outsourced system. The observations were made with the outsourced company tosee how the employees work and fill information gaps that the interviews could notcover.