• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 27
  • 13
  • Tagged with
  • 40
  • 40
  • 28
  • 24
  • 22
  • 20
  • 14
  • 13
  • 12
  • 10
  • 9
  • 9
  • 9
  • 8
  • 8
  • 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.
11

Hur förändras en fönstermodells U-värde beroende på dess geometri? : En fallstudie utförd på en verklig fönstermodell

Wernh, Emil January 2023 (has links)
Ett fönsters värmeisolerande egenskaper är nödvändiga att känna till för den som köper fönstren eftersom det ställs krav på en byggnads energianvändning vid ny- och ombyggnation. Det är även en kostnadsfråga då energi för att värma eller kyla byggnader måste betalas för. Ett fönsters värmeisolerande egenskaper beskrivs med dess U-värde. För fönster som tillverkas i fasta mått kan ett U-värde antingen mätas eller beräknas enligt standarder och sedan uppges för beställaren av fönstret. När fönster inte tillverkas i fasta mått blir det en tidskrävande procedur att för varje nytt fönstermått beräkna eller mäta fönstrets U-värde. Syftet med detta arbete var att utifrån U-värdesberäkningar för flera olika måttkonfigurationer av fönstermodellen "A" som tillverkas på måttbeställning av "B" fastställa sambandet mellan dess geometri och dess U-värde. Fönstret är ett renoveringsfönster som monteras i en byggnads befintliga fönsterkarmar. Genom att fastställa sambandet mellan geometri och U-värde fastställs hur fönstrets totala U-värde påverkas av den karm som det monteras i. Tanken var att "B" skulle kunna använda resultaten för att ange fönstermodellens U-värde vid beställning av ett specifikt mått. Resultatet kan också vara intressant för andra fönstertillverkare, köpare av fönster, konsulter, ackrediteringsorgansitationer och fönsterbranschen i stort. Dels eftersom sambandet mellan fönstergeometri och U-värde fastställes, men även då arbetet ger en ingående beskrivning av hur aktuella standarder kan användas. Fönstrets U-värde beräknades enlig SS-EN ISO 10077-1 och karmens U-värde beräknades enligt SS-EN ISO 10077-2. Glaskassettens U-värde var känt sedan tidigare och beräknades inte i detta arbete. Mjukvara användes för att beräkna karmens U-värde.' Resultatet visade att fönstermodellens U-värde minskar då dess area ökar. Det visade också att rektangulära fönster fick ett lägre U-värde ju mer kvadratiska de blev till formen. Detta gällde oavsett om fönsterhöjden var större än fönsterbredden och vice versa. Höga fönster hade ett lägre U-värde än låga fönster på grund av att karmen hos denna fönstermodell hade olika U-värden på sidorna och upptill och nedtill. Diagram har tagits fram på fönstrets U-värde i olika geometrier, storlekar och utföranden. Det visade sig att standarderna som användes är bättre lämpad för att jämföra olika fönstermodellers U-värden snarare än att undersöka hur en enskild fönstermodells U-värde förändras med dess geometri då standarderna i vissa avseenden inte tar hänsyn till fysikaliska lagar. För att noggrannare undersöka hur ett fönsters storlek och geometri påverkar dess U-värde bör framtida studier fokusera på att utföra värmetekniska simuleringar, snarare än att räkna enligt standarderna som använts i detta arbete. / The thermal insulation properties of a window are essential to know for the purchaser since there are energy use regulations concerning construction of new buildings or those undergoing deep renovations. It’s also a matter of cost since energy for heating and cooling a building must be paid for. The thermal insulating properties of a window is described with its U-value. The thermal properties for windows produced in fixed sizes could be measured or calculated according to standards and be presented to the purchaser of the window. When windows are not manufactured in fixed sizes a great deal of work must be done to calculate or measure the U-value for each individual window size. The purpose of this report was to establish the relationship between the geometry and the U-value for the window model "A" which is manufactured in customer requested sizes by "B". The establishment of the relationship between U-value and geometry was accomplished through U-value calculations for different size configurations of the window. The window is a renovation window which is mounted onto a buildings already existing window frames. By establishing the relationship between the geometry and the U-value, it can be known how the U-value of the window is affected by the frame it is mounted on. The idea was that "B" would be able to use the results to be able to specify the U-value when receiving an order of a window of a specific size. The results could potentially be of interest to other window manufacturers, purchaser of windows, consultants, accreditation organizations and the window industry in general. Partly because the relationship between the window geometry and its U-value is established, and partly because the thesis gives an in depth explanation of how relevant standards can be used. The U-value of the window was calculated in accordance with SS-EN ISO 10077-1 and the U-value of the frame in accordance with SS-EN ISO 10077-2. The glazing part of the window was already known and therefore not calculated in this work. Software was used to calculate the U-value of the frame. Results showed that the U-value of the window model declined when its area increased. It also showed that rectangular windows got a lower U-value as it becomes more square shaped. This applied regardless of if the window height was greater than the window width or vice versa. Tall windows had a lower U-value than short windows because the upper, lower, and side members of this window models frame had different U-values. Diagrams have been produced showing the U-value of the window model in different geometries, sizes, and designs. It turned out the standards that was used is better suited to compare different window models U-values rather than to investigate how the U-value of a specific window varies with its geometry because the standards in some regards does not consider physical laws. To more accurately investigate how a windows size and geometry affects its U-value further studies should focus on performing heat transfer simulations, rather than calculate according to the standards that was used in this paper.
12

JÄMFÖRELSE MELLAN TRÄREGELVÄGG OCH LÅGENERGI LÄTTBETONGVÄGG : Byggteknik, värmeförmåga och byggekonomi.

Kahachi, Marwan January 2024 (has links)
Commencing with a foundational understanding of the vital role energy modeling plays in optimizing building performance, this study meticulously compares a lowenergy lightweight concrete wall with a wooden stud wall featuring an air gap. The objective is to determine the most advantageous wall type for the construction phase, considering factors such as energy efficiency and cost-effectiveness. Additionally, comprehensive calculations will be performed to assess the heat resistance of each wall type and ascertain the most cost-effective option in terms of heating expenses for residential purposes.Acquiring pertinent information to successfully complete this study, our analysis considers variations in calculations based on whether the lightweight concrete wall is homogeneous or if the wooden stud wall consists of diverse materials.The findings of this study underscore that low-energy lightweight concrete walls offer notable advantages in terms of production aspects, primarily due to cost savings during the construction process. Moreover, in direct comparison to conventional lightweight concrete blocks, the study demonstrates that low-energy blocks outperform wooden stud walls in terms of energy efficiency and consumption.
13

Attefallshus insulated with Vacuum Insulated Panels

Emre Sunal, Egill January 2016 (has links)
Stockholm lies at the top in Europe in terms of population growth. It is growing from 30,000 to 40,000 residents each year and therefor puts high demands on the regions development. One of the governments reactions to this housing problem was to approve a bill that would simplify the regulatory framework in the planning and building act. It will among other permit owners of a one-or two family houses to build a 25  compliment housing without a building permit, so called attefallshus. In this final project, a small 25  house is designed. The house was designed to have thin exterior walls to maximize the indoor living space and also to fulfill all the Boverkets regulations for permanent housing. Vacuum Insulated panels were used as an insulation material in the envelope to achieve the extra thin exterior walls to maximize the living space. Various different simulations were done to simulate: Heat- and moisture transfer through the exterior walls, thermal bridges, energy calculations and the daylight factor inside the house. Additional calculations were done in Excel to compare the mean U-value calculated in simulations. The moisture transfer simulation did show that there should not be any moisture problems in the exterior walls. The mean U-value calculations in Excel and in the simulations showed values less than the limitations of Boverkets building regulations.
14

Akustisk mätning av U-värde

Brycki, Marcin January 2015 (has links)
This pre-study investigates the possibility of U-value measurements through an acoustic method. A hypothesis about an acoustic model built on acoustic theories combined with U-value theories is presented to answer the questions:•Can U-value theory be combined with acoustic theories?•Can the coefficient of heat be affirmed trough an acoustic measurement?The idea for this dissertation begun with a logical idea in mathematical similarity, between the coefficient of heat transmission units and sound intensity units. The U-value theory is based on assumptions such as initial resistance for inner walls and initial resistance for outer walls. The resistance in the material is interpreted through sound intensity theory.The argument is built upon mass law theory, which means if the frequency or thickness of the material layer doubles it implies an increase of sound reduction by 6 dB. Six different materials; foam, glas fiber insulation, MDF, gypsum, concrete and glass are being investigated through Insul 7 simulations. A practical lab assessment with two glass fiber insulation boards with different density is presented. These fiberboards were received from Saint-Gobain Isover, with alredy measured density and lambda value.The conclusions are drawn from simulations, practical lab testing and different theories. This dissertation confirms that it´s possible to use an acoustic model for U-value measurements, but the hypothesis need a further investigation. That means that the hypothesis is based on mass law theory only and the second degree effects are not calculated in this model. In other words, the model will most probably work better for materials with low density and will be less reliable on materials with high density.
15

Anpassning av timmerhus enligt nya energikrav i BBR 29 : Glass House Villa 126 / Adaptation of log houses according to new energy requirements in BBR 29 : Glass House Villa 126

Carlsson, Linus, Liljenberg, David January 2021 (has links)
Den 1 september 2020 trädde den konsoliderade versionen av Boverkets Byggregler BBR 29 i kraft. En stor del av skillnaden från föregående version var det ökade kravet på energihushållning. Det nya kravet som fastställts innebär att U-medelvärdet är sänkt från 0,4 W/m2K till 0,3 W/m2K. Detta är ett mått på hur väl en byggnad är isolerad. Företaget Kontio expanderade till Sverige från Finland för snart fyra år sedan. De säljer framförallt fritidsboende och småhus byggda av egentillverkade timmerstockar med korslimmad arktisk furu i olika dimensioner. Deras hus säljs på den finska marknaden, men i Sverige har endast vissa timmerdimensioner klarat det gamla kravet från BBR 28. Med det nya kravet måste klimatskärmen anpassas till den nya kravbilden. Tak och golv är färdigprojekterade med låga U-värden, därför finns den största möjligheten för anpassning i väggkonstruktionerna. Med hjälp av givna förutsättningar togs ett antal väggkonstruktioner fram för beräkning av U-värdet. Dessa gav upphov till olika typlösningar som varierar med, förutom väggkonstruktionen, fönstertyper och minskade fönsterareor. Framräknat U-värde för väggkonstruktion låg till grund för beräkning av U-medelvärde tillsammans med U-värde för fönster, golv och tak. Ändringar i väggkonstruktioner kan resultera i en förekomst av fuktproblem. Därför testas dessa med hjälp av en Glaser-tabell som undersöker genom stationära beräkningar huruvida det föreligger någon risk i framtagna väggkonstruktioner. Detta projekt analyserar även för- och nackdelar med timmer i furu och dess värmelagrande funktion som beror på en hög värmekapacitet. Med utgångspunkt i litteraturstudien analyseras och utreds var i konstruktionen man med störst fördel placerar den massiva timmerstrukturen i förhållande till värmeisolering. Alla väggkonstruktioner behövde göras om utom 275 där endast fönstertyp ändrades till de med lägre U-värde. Vid anpassning av väggkonstruktioner med timmerdimension 135 och 205 krävdes mer omfattande åtgärder. Genom att isolera väggarna, ändra fönstertyper och minska fönsterareor kunde kravet på U-medelvärde nås på olika sätt. Ingen av dessa vägguppbyggnader uppvisade tecken på fukttekniska problem. / On September 1, 2020, the consolidated version of the National Board of Housing, Building and Planning's Building Rules BBR 29 took effect. A large part of the difference from the previous version was the increased demand for energy management. The new requirement that has been established means that the mean U-value has been reduced from 0.4 W/m2K to 0.3 W/m2K. This is a measurement of how well a building is insulated. Almost four years ago, the company Kontio expanded to Sweden from Finland. They mainly sell holiday homes and living houses built from self-made logs with cross-laminated arctic pine in various dimensions. Their houses are sold on the Finnish market, but in Sweden only certain timber dimensions have met the old requirement from BBR 28. With the new BBR 29, the building shell must be adapted to the new requirement. Ceilings and floors are pre-designed with low U-values and for this reason further improvements are best made in the wall construction. Using the given conditions, a number of wall constructions were developed for calculating the U-value. These gave rise to different type solutions that vary with, in addition to the wall construction, window types and reduced window areas. Calculated U-value for wall construction was the basis for calculating the mean U-value together with the U-value for windows, floors and ceilings. Changes in wall constructions can result in the occurrence of moisture problems, therefore these walls are tested using a Glaser-table which examines, by stationary calculations, whether there is any risk in the adapted constructions. This project also analyzes the advantages and disadvantages of pine timber and its heat storage function due to its high heat capacity. Based on the literature study, it is analyzed and investigated where in the construction the massive timber structure is placed with the greatest advantage in relation to the thermal insulation. All wall constructions needed to be adapted except 275 where only the window type was changed to those with a lower U-value. When adapting wall constructions with timber dimensions 135 and 205, more extensive measures were required. By insulating the walls, changing window types and reducing window areas, the requirement for the mean U-value could be achieved in various ways. None of these wall constructions showed signs of moisture technical problems.
16

The effects of low-emissivity window films on thermal comfort and energy performance of a historic stone building in cold climate: computer simulations with "IDA ICE"

Abolghasemi Moghaddam, Saman January 2019 (has links)
Low-emissivity (low-E) window films are designed to improve the energy performance of windows and prevent indoor overheating by solar radiation. These films can be applied to different types of glazing units without the need for changing the whole window. This characteristic offers the possibility to improve the energy performance of the window of old and historic buildings for which preservation regulations say windows should remain more or less unchanged. This research aims to figure out to what extent a low-E window film can improve thermal comfort and energy performance of an old three-storey historic stone building in the cold climate of Mid-Sweden. In this research, first, with help of the simulation software “IDA ICE”, the entire building was modelled without window films in a one-year simulation. Second step was to add the low-E window films (3M Thinsulate Climate Control 75 (CC75)) to all the windows and repeat the simulation. Comparison between the results of the two cases revealed an improvement in energy use reduction as well as the thermal comfort when applying the films. For the application of the window films, a cost analysis using payback method was carried out which showed a long- time payback period. Although an investment with a long-time payback period is considered as a disadvantage, for historic buildings with very strict retrofit regulations specially when it comes to the building’s facades, application of the low-emissivity window films for better energy performance and thermal comfort is among the recommendable measures, but not necessarily the best.
17

Optical Characterization and Energy Simulation of Glazing for High-Performance Windows / Optisk karakterisering och energisimulering av smarta fönster

Jonsson, Andreas January 2009 (has links)
This thesis focuses on one important component of the energy system - the window. Windows are installed in buildings mainly to create visual contact with the surroundings and to let in daylight, and should also be heat and sound insulating. This thesis covers four important aspects of windows: antireflection and switchable coatings, energy simulations and optical measurements. Energy simulations have been used to compare different windows and also to estimate the performance of smart or switchable windows, whose transmittance can be regulated. The results from this thesis show the potential of the emerging technology of smart windows, not only from a daylight and an energy perspective, but also for comfort and well-being. The importance of a well functioning control system for such windows, is pointed out. To fulfill all requirements of modern windows, they often have two or more panes. Each glass surface leads to reflection of light and therefore less daylight is transmitted. It is therefore of interest to find ways to increase the transmittance. In this thesis antireflection coatings, similar to those found on eye-glasses and LCD screens, have been investigated. For large area applications such as windows, it is necessary to use techniques which can easily be adapted to large scale manufacturing at low cost. Such a technique is dip-coating in a sol-gel of porous silica. Antireflection coatings have been deposited on glass and plastic materials to study both visual and energy performance and it has been shown that antireflection coatings increase the transmittance of windows without negatively affecting the thermal insulation and the energy efficiency. Optical measurements are important for quantifying product properties for comparisons and evaluations. It is important that new measurement routines are simple and applicable to standard commercial instruments. Different systematic error sources for optical measurements of patterned light diffusing samples using spectrophotometers with integrating spheres have been investigated and some suggestions are made for how to avoid such errors.
18

Passivhus ur en brukares perspektiv / Passive houses from a user's perspective

Samuelsson, Marcus, Lüddeckens, Thomas January 2009 (has links)
Ett passivhus är ett hus som i stort sett enbart värms upp av människorna och elapparaterna som finns i huset. Särskilda krav för att få kalla huset för passivhus måste uppfyllas. Vi har gjort en enkätundersökning på tre olika passivhusprojekt för att utreda vad de boende tycker om inomhusklimatet. De utvalda projekten finns i Värnamo, Frillesås och Glumslöv. Enkätsvaren visar att de boende i Frillesås är mycket nöjda, medan mer än 50 % av dem som bor i Glumslöv tycker att det är för varmt på sommaren och för kallt på vintern. För att utreda om de olika konstruktionerna har någon inverkan på inomhusklimatet har beräkningar och simuleringar i datorprogrammen VIP+ och IDA gjorts. Resultaten från de båda programmen visar att vilken av de två konstruktionerna som valts inte bör ha någon påverkan på inomhusklimatet. / A passive house is a house that is mostly heated with energy from humans and from electric devices in the house. Special requirements need to be followed if you want to call the house a passive house. We did a survey on three different passive house projects to investigate the tenants opinion about the indoor climate. The chosen projects are located in Värnamo, Frillesås and Glumslöv. The result of the survey shows that the tenants in Frillesås are very satisfied, while more than 50 % of the tenants in Glumslöv think it’s too hot in the summer and too cold in the winter. To investigate if the construction has any effect on the indoor climate, we did calculations and simulations in the computer programs VIP+ and IDA. The result from both of the programs shows that the chosen construction should not effect the indoor climate.
19

Passivhus ur en brukares perspektiv / Passive houses from a user's perspective

Samuelsson, Marcus, Lüddeckens, Thomas January 2009 (has links)
<p> </p><p>Ett passivhus är ett hus som i stort sett enbart värms upp av människorna och elapparaterna som finns i huset. Särskilda krav för att få kalla huset för passivhus måste uppfyllas.</p><p>Vi har gjort en enkätundersökning på tre olika passivhusprojekt för att utreda vad de boende tycker om inomhusklimatet. De utvalda projekten finns i Värnamo, Frillesås och Glumslöv. Enkätsvaren visar att de boende i Frillesås är mycket nöjda, medan mer än 50 % av dem som bor i Glumslöv tycker att det är för varmt på sommaren och för kallt på vintern. <strong></strong>För att utreda om de olika konstruktionerna har någon inverkan på inomhusklimatet har beräkningar och simuleringar i datorprogrammen VIP+ och IDA gjorts. Resultaten från de båda programmen visar att vilken av de två konstruktionerna som valts inte bör ha någon påverkan på inomhusklimatet.</p><p> </p> / <p><p>A passive house is a house that is mostly heated with energy from humans and from electric devices in the house. Special requirements need to be followed if you want to call the house a passive house.<strong></strong></p><p>We did a survey on three different passive house projects to investigate the tenants opinion about the indoor climate. The chosen projects are located in Värnamo, Frillesås and Glumslöv. The result of the survey shows that the tenants in Frillesås are very satisfied, while more than 50 % of the tenants in Glumslöv think it’s too hot in the summer and too cold in the winter.</p>To investigate if the construction has any effect on the indoor climate, we did calculations and simulations in the computer programs VIP+ and IDA. The result from both of the programs shows that the chosen construction should not effect the indoor climate.</p>
20

Creation of a Low Energy Building with the help of Energy Simulation

Anastasopoulou, Kyriaki January 2017 (has links)
In this Thesis Project, the creation of a Low Energy building was examined in order to investigate how complex was to select the suitable parameters and systems of the dwelling, aiming to achieve the lowest possible energy consumption in one year period. All the technologies implemented into the system intended to be as energy efficient and profitable as possible. Another objective of this study was also to present the potential of the system to produce a part of the consumed energy, through renewable energy sources, approaching by this way also the standards of a Zero Energy Building. Firstly, the floor plan of the 150 m2 detached house, was drawn in the designing program AutoCAD. In continuation, this 2D floor plan was imported into the simulation program as well as all the initial input data so as for the Base model of the building to be created For the analysis of the building, the Simulation Program IDA ICE 4.7 was used. Gradually, alternations and adjustments were made into the Base model. Different models were created planning to analyze their results and conclude to the proper solution. All the simulations run for one year time period in order to present the total energy usage, system’s losses and demands in each case. In addition, as for the current study, the location of the construction was Athens, all building’s characteristics were chosen to comply with the Greek Regulation for Low Energy Buildings. Finally, through the procedure followed after having accomplished a series of simulations, the final annually energy demands managed to be within the required limits. / <p>Online Presentation</p>

Page generated in 0.0395 seconds