This diploma thesis deals with not-aged and thermally, electric and multistress aged slotted isolations dielectric properities experimental probing. Dutiny experiment is watched influence moisture on dielectric properties insulating materiále ISONOMŽNMN. Especially both two permitivity complex components are surveyed, in dependence on the frequency and the temperature changes during thermal, electric and multistress ageing. These characteristics are viewed in light of application the isolation in practice.

The main theme of dissertation theses is systems of ventilation and air-condition used in buildings. Work consists of analyse of this systems and parameters of indoor clime whose are affected by them. It summarizes demands on the process of calculation the energy efficiency of the building services by actual legislative. On one chosen type of building is done the energy simulation of implemented systems of ventilation and air-condition by energy efficiency and their specific need of energy.

För att ha en chans att ändra trenden med ökande utsläpp av växthusgaser är internationella samarbeten nödvändiga. Därför har EU genom miljökvalitetsmålet Begränsad Miljöpåverkan satt krav på högsta tillåtna utsläpp av växthusgaser. Att sänka energianvändningen för upp- värmning är ett steg i att även sänka utsläpp av koldioxid, som är en av växthusgaserna. Sänkning av energianvändning kan göras på flera sätt, bl.a. genom att öka tjockleken på isoleringen eller återvinna värmen i frånluften. Men dessa åtgärder ska inte helt okritiskt göras.  Att använda roterande värmeväxlare är ett sätt att återvinna värmen i frånluften. Luften passerar då en rotor med öppna kanaler som roterar kring sin egen axel över till tilluftssidan. Detta möjliggör fuktöverföring oberoende om rotorn är hygroskopisk eller ej. Dvs. möjligheten för kanalväggen att ta upp vattenmolekyler eller inte.  Mätningar av relativ fuktighet, temperatur och daggpunkt har gjorts på tre objekt. Därefter har ånghalter och verkningsgrader beräknats. Med objekt menas småhus där roterande värmeväxlare installerats i ventilationssystemet. Objekten är belägna i Linköping, Stockholm och Norge. Ett beräkningsexempel har ställts upp som visar hur fuktverkningsgraden påverkas av olika fukttillskott. I verkligheten råder dock inte stationära förhållanden för fukttillskottet som är en förutsättning för resultaten på dessa beräkningsexempel.  I denna rapport kommer den skrivande således fram till att fuktåterföring sker även för icke hygroskopiska värmeväxlare. Även att fuktverkningsgraden svarar med en viss tröghet vid återhämtning av ett tillfälligt förhöjt fukttillskott. Fuktverkningsgraden är dock betydande för fukttillskott över ca 1-2 g/m3. / To have a chance to change the trend of increased greenhouse gases are international collaborations necessary. Therefore, the EU through the environmental quality objective of Reduced Environmental Impact sat requirements for maximum allowable emissions of greenhouse gases. Reducing energy use for heating is a step that also reduces emissions of carbon dioxide; which is one of the greenhouse gases. Reducing energy use can be done in several ways, including by increasing the thickness of the insulation or heat recovery from exhaust air. However, these measures should not be uncritically made. The use of a rotating heat exchanger is a means to recover heat from exhaust air. The air then passes a rotor with open channels that rotates around its own axis over to the supply air side. This allows moisture transfer regardless of whether or not the rotor is hygroscopic. That is, the ability of the channel wall to take up water molecules or not.  Measurements of relative humidity, temperature and dew point has been made on three objects. Thereafter steam content and efficiencies was calculated. In other words, the objects are referred to single- ore two-family homes where a rotary heat exchanger is installed in the ventilation system. The objects are located in Linköping, Stockholm and Norway. An example calculation is set up that shows how moisture efficiency is affected by different moisture addition. In reality in which the conditions is not stationary the moisture supplement that is a prerequisite for the results of these calculation examples.  In this report, the writer thus concluded that moisture reversal will occur even for non- hygroscopic heat exchangers. Although the moisture efficiency corresponds with a certain slowness in the recovery of a temporarily elevated moisture addition. Moisture efficiency is significant for moisture supplement of about 1-2 g/m3.

Methods of solving the steady state characteristics of a node matrix equation system over a polymer electrolyte fuel cell (PEFC) were evaluated. The most suitable method, referred to as the semi-implicit method, was set up in a MATLAB program. The model covers heat transfer due to thermal diffusion throughout the layers and due to thermal advection+diffusion in the gas channels. Included mass transport processes cover only transport of water vapor and consist of the same diffusion/advection schematics as the heat transfer processes. The mass transport processes are hence Fickian diffusion throughout all the layers and diffusion+advection in the gas channels. Data regarding all the relevant properties of the layer materials were gathered to simulate these heat- and mass transfer processes.Comparing the simulated temperature profiles obtained with the model to the temperature profiles of a previous work’s model, showed that the characteristics and behavior of the temperature profile are realistic. There were however differences between the results, but due to the number of unknown parameters in the previous work’s model it was not possible to draw conclusions regarding the accuracy of the model by comparing the results.Comparing the simulated water concentration profiles of the model and measured values, showed that the model produced concentration characteristics that for the most part alignedwell with the measurement data. The part of the fuel cell where the concentration profile did not match the measured data was the cathode side gas diffusion layer (GDL). This comparison was however performed with the assumption that relative humidity corresponds to liquid water concentration, and that this liquid water concentration is in the same range as the measured data. Because of this assumption it was not possible to determine the accuracy of the model.

No description available.

The project aims to develop a methodology to study the variation in properties of wood polymer composites (WPC’s) with/without surface treatment at different humidity conditions. The project aims to investigate the behavior of biocomposites at 50%, 80%and 100% relative humidity (RH). Also to clarify if the hydrophilization effect helps to preserve the structural integrity of the materials for longer periods at these conditions. The comparison between biocomposites comprising polypropylene (PP) with both untreated wood fibers (WF) or FibraQ (hydrophobic surface-treated wood fibers from Biofiber Tech) was made. The focus was on the mechanical properties, water absorption, macro- and microstructures. The results show that PP comprising FibraQ exhibits lower moisture uptake than the PP comprising untreated WF at high relative humidity conditions. The mechanical properties did not seem significantly affected by the surface treatment at high relative humidity conditions. It is also concluded that since the study only ran for four weeks, there was not enough time to fully understand the influence of moisture uptake over the materials’ properties.

No description available.

No description available.

This report intends to investigate climate conditions and energy consumption in Gränby Ice rink in Uppsala.Today, Gränbyhallen faces a potential renovation project to modernize and improve what was initially intended as a temporary hall that was inaugurated in 1974.In 2021, the property was taken over by the Uppsala municipality Arenor och Fastigheter AB from having previously been owned by the municipality. Since then, Arenor och Fastigheter has worked to modernize its facilities and in this way also work to improve the energy consumption required by the operation of the Gränby ice rink and also examine the indoor climate conditions in the building.The idea is to make the climate more pleasant for the visitors, and therefore making it less cold and barren temperaturevise by separating the ventilation from the ice and bleachers so that these can be controlled individually. The hope is to be able to reduce energy consumption with such a solution by seeing if the facility has heat leakage from the outside and how moisture can be managed in the facility to be kept at a more even level throughout the year and during the day.For the report, weather data was obtained from SMHI and then compiled and compared with temperatures and energy consumption from sorption dehumidifiers and the plant total to locate current deficiencies but also how to potentially address these to lower energy consumption.Analysis of the data was also done for the outdoor temperature which was set against the indoor temperature and then also the difference between the two to see the difference anddemonstrate how well insulated the facility is. On average over the entire time investigated, there was only +1°C difference between outside and inside, which gives an indication that the insulation in the facility needs to be reviewed and improved both outside and inside as there are large leaks in the facility with open surfaces and only metal doors that separate warm surfaces from cold.The analysis also suggests that the dehumidifier should be changed to regulate according to the dew point temperature from regulating according to the relative humidity as the dew point changes less over time and is less affected by the amount of water in the air which changes from hour to hour and is also affected by the outdoor climate when doors are opened and closed to the facility. / Denna rapport avser att undersöka klimatförhållanden och energiförbrukningen i Gränby ishall i Uppsala. Idag står Gränbyhallen inför ett potentiellt renoveringsarbete för att modernisera och förbättra till en som till en början var tänkt som en provisorisk hall från 1974. 2021 togs fastigheten över av Uppsala kommun Arenor och Fastigheter AB från att tidigare varit kommunägt. Arenor och Fastigheter har sedan dess arbetat med att modernisera sina fastigheter och på så sätt även arbeta med att förbättra energiförbrukningen som driften i Gränby ishall kräver och även undersöka klimatförhållandena inomhus. Tanken är att göra klimatet för åskådarna mer behagligt att vistas i från dagens kalla och karga temperaturer genom att separera läktarens ventilation och avfuktning från isens, så att dessa kan styras enskilt och därmed ha olika klimat. Förhoppningen är att med en sådan lösning kunna minska energiförbrukningen genom att se ifall anläggningen har värmeläckage från utsidan samt hur fukt kan hanteras i anläggningen för att hållas på en mer jämn nivå över året och under dagen. Till rapporten har väderdata hämtats från SMHI och sedan sammanställts och jämförts med temperaturer och energiförbrukning från sorptionsavfuktare och anläggningens total för att lokalisera nuvarande brister, men även hur man kan potentiellt åtgärda dessa för att sänka energiförbrukningen. Analys av data gjordes även för temperaturen utomhus mot temperaturen inomhus och då differensen av de två för att se skillnaden och påvisa även hur väl isolerad anläggningen är. I genomsnitt över hela tiden som undersöktes skildes det bara +1°C mellan ute och inne, vilket ger indikation på att isoleringen i anläggningen behöver ses över och förbättras både ute och inne då det finns stora läckage i anläggningen med öppna ytor och endast plåtdörrar som separerar varma ytor från kalla. Analysen tyder även på att avfuktaren bör ändras till att reglera efter daggpunktstemperaturen i stället för som nu efter relativa luftfuktigheten. Daggpunkten ändras mindre över tid och påverkas mindre av luftens vattenmängd, som ändras från timme till timme och som påverkas även av utomhusklimatet när dörrar öppnas och stängs till anläggningen.

In this thesis the oxidation of monoterpenes by O3 and NO2 and factors that influenced the oxidation were studied. In the environment both ozone (O3) and nitrogen dioxide (NO2) are present as oxidising gases, which causes sampling artefacts when using Tenax TA as an adsorbent to sample organic compounds in the air. A scrubber was developed to remove O3 and NO2 prior to the sampling tube, and artefacts during sampling were minimised when using the scrubber. The main organic compounds sampled in this thesis were two monoterpenes, alfa-pinene and delta-3-carene, due to their presence in both indoor and outdoor air. The recovery of the monoterpenes through the scrubber varied between 75-97% at relative humidities of 15-75%. The reactions of alfa-pinene and delta-3-carene with O 3, NO2 and nitric oxide (NO) at different relative humidities (RHs) and reaction times were studied in a dark reaction chamber. The experiments were planned and performed according to an experimental design were the factors influencing the reaction (O3, NO2, NO, RH and reaction times) were varied between high and low levels. In the experiments up to 13% of the monoterpenes reacted when O3, NO2, and reaction time were at high levels, and NO, and RH were at low levels. In the evaluation eight and seven factors (including both single and interaction factors) were found to influence the amount of alfa-pinene and delta-3-carene reacted, respectively. The three most influencing factors for both of the monoterpenes were the O 3 level, the reaction time, and the RH. Increased O3 level and reaction time increased the amount of monoterpene reacted, and increased RH decreased the amount reacted. A theoretical model of the reactions occurring in the reaction chamber was created. The amount of monoterpene reacted at different initial settings of O3, NO2, and NO were calculated, as well as the influence of different reaction pathways, and the concentrations of O3 and NO2, and NO at specific reaction times. The results of the theoretical model were that the reactivity of the gas mixture towards alfa-pinene and delta-3-carene was underestimated. But, the calculated concentrations of O3, NO2, and NO in the theoretical model were found to correspond to a high degree with experimental results performed under similar conditions. The possible associations between organic compounds in indoor air, building variables and the presence of sick building syndrome were studied using principal component analysis. The most complex model was able to separate 71% of the “sick” buildings from the “healthy” buildings. The most important variables that separated the “sick” buildings from the “healthy” buildings were a more frequent occurrence or a higher concentration of compounds with shorter retention times in the “sick” buildings. The outcome of this thesis could be summarised as follows; - - - -