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374 Uppsatser om Solar thermal - Sida 11 av 25
LAN-Uppgradering
The interest in small-scale electricity in Sweden has increased strongly in recent years. The interest is noticeable both among politicians to increase the share of renewables in the energy mix, and among electricity consumers to partially replace purchased electricity with self-produced. This has resulted in a significant increase of electricity production in low voltage grids in recent years, and the trend appears to continue in the coming years. The majority of the new production plants are solar cells, followed by wind turbines, and it is also in these the greatest efforts are made in this paper.Distributed generation is often seen as something positive since it will contribute to reduced transmission losses and reduced voltage drop in the networks, and that it increases the share of electricity from renewable sources. In cases where the grids are not strong enough, or in other ways not adapted to manage the installed production, power quality may be adversely affected.
Termisk hantering av litium-jon- batterier i elektriska drivsystem
The automotive market is currently undergoing a historical change where stricter emission legislations and ever increasing fuel costs have intensified the search for effective alternatives to the conventional internal combustion engine, which has resulted in a substantial trend towards electrification of powertrains. Storage of electrical energy is the fundamental component in this technology where the lithium-ion batteries are currently considered as the most appropriate solution. Lithium-ion batteries, however, as other types of batteries, can only be used efficiently and durably within a specific temperature range.This Master thesis has been carried out in collaboration with Electroengine in Sweden AB, situated in Uppsala, which has an ongoing project regarding development of a modular battery system for electric powertrains. The project is at a stage where an initial prototype has been developed which provides the foundation for this thesis. The study has addressed the battery system performance from a thermal perspective, in order to validate the ability of the system to create a thermally serviceable environment for the lithium-ion battery cells.
Säkerhetsegenskaper hos en rymdreaktor
A Monte Carlo simulation of the ELECTRA reactor using (U,Zr)N fuel and a liquid lithium coolant is performed using the Serpent simulation code. The results show a reactor with a total reactivity coefficient of the coolant, fuel and material expansion that is strongly negative. These properties make the ELECTRA reactor a good candidate for a safe space reactor that could be used for propulsion of manned and unmanned space vehicles to Mars and other parts of our solar system..
Smarta lokala energisystem, Vision-Teknik-Tillämpning
The energy sector is facing an impending paradigm shift. Today?s technology enables the end-user to generate their own energy locally at home. Furthermore, recently developed storage technologies make it possible to balance energy demand with stored energy and integrate district heating with the local power grid. This means that in the future heat and electric power will interact and energy flows is converted over energy boundaries.
Skapandet av ett byggnadsfysikaliskt detaljbibliotek åt byggnadskonstruktörer : fokus på fukt- och värmetillstånd i köldbryggor
Det konstrueras i stor utsträckning bristfälliga detaljlösningar på byggnader i dagsläget. Den bärande stommen i konstruktionen prioriteras ofta medan det inte ägnas lika mycket fokus åt att tillgodose de byggnadsfysiska aspekterna. Anledningen till de bristfälliga detaljerna är även att den som utför arbetet saknar rätt kunskap och tid. För att skapa en förbättring behövs ett hjälpmedel!Kunskap och erfarenhet om hur bra detaljer skapas finns redan i företag, svårigheten är dock att sprida kunskapen till de som är i behov av den.Målet med denna rapport är att skapa en metodik som blir startskottet för ett omfattande arbete kring framtagandet av ett detaljbibliotek, vars syfte är att sprida byggnadsfysiska kunskaper inom företaget och inspirera konstruktörer till att konstruera bra detaljlösningar. Biblioteket ska innehålla byggnadsfysiskt utredda detaljlösningar som analyserats enligt den utarbetade metodiken.
Uppvärmningssystem : Ekonomi, miljö och drift
This bachelor thesis aims at investigate how a specified house can optimize its energy consumption.Today the house often stands for the major part of the energy consumption in a consumers? life,whereas an energy optimization creates economic as well as environmental advantages. It is importantto make old houses more energy efficient, but putting high energy demands on new houses could beargued to be more important. The installations functions as both the heart and brain in a house, thusmaking it important to energy optimize these. Since the background describes the importance ofenergy efficiency and optimization in a house, the focus area of this report will be an investigation ofdifferent types of heating systems in order to be able to choose the one most suited for the house.Aspects considered when choosing the heating system was how economic the system is both inservice- and investment costs and how environmental and operational friendly the system is.Through literature reviews there were sufficient information gathered that served as a foundation whencomparing and choosing between the four systems - district heating, pellet-fired boiler, geothermalheating and solar heating.
Torrefaction of biomass : a comparative and kinetic study of thermal decomposition for Norway spruce stump, poplar and fuel tree chips
Stump biomass is energy rich and stump harvesting for use as fuel become more and more
interesting in Sweden. Swedish Forest Agency (2009) has estimated that stump harvesting in
Sweden would respond to an annual energy supply of 57 TWh/year. However, stump has not
been recognized as a bioenergy resource in Sweden. Suitable methods for pre-treatment of
stump are probably of great importance to make it accepted as fuel. It is therefore rewarding
to carry out an investigation in this area for stump.
This report represents results from a diploma project, which was aimed to develop a fixed bed
reactor for experimental study of biomass torrefaction, followed by TG analysis and kinetic
modelling employing Ozawa method and different kinetic models including one-step and
three-pseudo-component models.
Konstruktion av värmespridare med grafit för flygelektronik
This master thesis was carried out for Saab Avitronics, a business unit of Saab ABactive in electronic systems for military aircrafts. Reliability and weight are of crucialimportance in this environment. To improve reliability and lower the weight graphitemay be used for electronics cooling. Graphite is an anisotropic material and hasthereof high thermal conductivity in two directions (in-plane) and a relatively lowconductivity in the third direction (through thickness).The purpose of this thesis was to investigate if graphite is an adequate thermalconductor to use in PCB carriers. The carriers support and cool the PCB by divertingthe heat dissipation from the PCB components to the edge.
Hantering av småskalig elproduktion : Utveckling av modell för dokumentation och elkvalitetsberäkningar
The interest in small-scale electricity in Sweden has increased strongly in recent years. The interest is noticeable both among politicians to increase the share of renewables in the energy mix, and among electricity consumers to partially replace purchased electricity with self-produced. This has resulted in a significant increase of electricity production in low voltage grids in recent years, and the trend appears to continue in the coming years. The majority of the new production plants are solar cells, followed by wind turbines, and it is also in these the greatest efforts are made in this paper.Distributed generation is often seen as something positive since it will contribute to reduced transmission losses and reduced voltage drop in the networks, and that it increases the share of electricity from renewable sources. In cases where the grids are not strong enough, or in other ways not adapted to manage the installed production, power quality may be adversely affected.
CFD simulering av kallras : Undersökning av temperatur- och luftbeteende intill höga glasfasader och i vistelsezon med golvvärme som en värmekälla
Glass has sophisticated front properties and are used as facades in high buildings. During cold periods, these glass facades could cause thermal discomfort, due to cold downdraught. Cold downdraught can be countered by placing heaters under glass surfaces. Nowadays technology offers highly insulating windows, which is why there is an interest to investigate the indoor climate with only underfloor heating. The research in this area is limited, and few empirical methods are available.
Broiler production in Zambia - management, growth, diseases and welfare
Successful broiler production in hot climates requires knowledge of how birds are affected by heat stress. It is important with access to water and good ventilation to facilitate coping with the heat. It may be useful to reduce the consumption of feed during the hottest hours of the days, which together with a few hours of extra light available could improve both productivity and animal welfare.
The vision in birds is superior to that of humans and most other mammals. Continuous light and light with low intensity can cause eye injuries, affect the eye development in young chicken negatively, as well as provide increased incidence of foot pad lesions. Access to light affects the production but also the welfare of birds.
En fallstudie om effektivisering av kosthanteringen inom Nybro kommun
In December 2008 the municipal council in Nybro, decided that the municipality shouldreduce the budget for food service. The budget should be reduced by 2 100 000 SEK.They decided that the children- and education committee, and the care committee would haveto lower their budget with 1 264 000 SEK respectively 636 000 SEK. The change have to bedone under two years, 60 % should be done under 2009 and 40 % under 2010.As a result of the decision, many kitchens have to become kitchens that only serve food, notcook it. This will result in preschool staff and nursing staff take over some of the tasks fromthe kitchen staff. The municipal council also decided that entrepreneurs could take over one(later two) cooking areas.A kitchen that serves food means that there isn?t any cooking involved.
Ekologisk slaktgrisproduktion i Sverige :
This literature review describes organic pig production in Sweden, its advantages and disadvantages, but also how its problems can be reduced or solved. Organic pigs have the possibility to a more natural behaviour than conventional pigs. With outdoor pigs comes problems, especially during wintertime, concerning water and feed supply, thermal environment and supervision. Parasites and leakage of plant nutrients are other difficulties that comes with outdoor pigs. All problems and difficulties can be reduced or put right through correct management.
Dagsljusdesign för en god visuell miljö
During our education to become lighting designers at Jönköping University, the artificial lighting has been in focus. Therefore we wanted to learn more about daylight. We chose to do this from a visual approach in open plan offices. Since daylight is part of the architects´ responsibility to master, we wanted to examine what architects think of when they plan daylight environments in open plan offices and how this is expressed in the buildings with focus on the visual factors.Our questions at issue are:What knowledge do architects have concerning daylight planning, and how do they use this knowledge in their practice?How well do the chosen daylight environments meet the end-users need of a good visual environment? The study consists of three case studies, carried out in the same way.
Enstudie om lågtempererat värmesystem i vägg : -Fokus på inomhusklimatet och energianvändning
Today the human being see energy as a matter of course but the resources that is used for extract energy is today not enough for the world demand. Of all the energy that is used in Sweden today approximately 40 % goes to the building stock. This number will most likely increase if not necessary actions will be made on the already existing building stock since new houses constantly are built which will be added up on the already existing energy supply. This takes cause of action on the already existing building stocks, to fulfill the demands of the future use of energy that has been set by the authority. At the same time the thermal conditions cannot be influenced by the necessary changes that must be made.