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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.
11

Quantitative thermal performance assessment of building envelopes – emergent practices and infrared thermography

Mahmoodzadeh, Milad 25 January 2022 (has links)
Since many buildings in Canada were built prior to the advent of national and provincial energy codes and standards, quantifying building envelope thermal performance in existing buildings is an important step in identifying retrofit opportunities. Due to the lack of building codes or standards for existing buildings in Canada, development of a rapid and robust quantitative approach to evaluate and rank buildings for vertical envelope retrofits is required. Hence, this dissertation sought to develop quantitative approaches to evaluate existing building envelope thermal performance in Canada and beyond. Following current professional practices, in Chapter 1, a comprehensive study was conducted on 49 campus buildings at the University of Victoria (UVic) to evaluate potential energy savings from vertical envelope retrofits, and to further validate those savings through more detailed energy models and parametric analyses for a subset of buildings. To this end, the thermal performance of a building envelope was quantified based on its heat loss coefficient (UA), obtained from multiplying its surface area (A) by its thermal transmittance (U-value). Heat loss calculations were used as a metric to inform envelope rehabilitation prioritization, while considering other data such as age and physical condition in parallel. Archetype energy models for selected buildings were used to evaluate the impacts of envelope retrofits on energy and GHG savings. The outcomes of this study allowed the University to weigh the benefits of improved energy performance from envelope retrofits against associated capital cost expenditures. Also, the implemented methodology and studied parameters unveiled a new horizon in evaluating the thermal performance of existing building envelopes in Canada, where a building code for existing buildings has not yet been established. Considering the economic findings of the envelope retrofits studied, it was concluded that in the absence of an existing building energy code, the University would likely require additional incentives, such as higher utility costs, higher carbon taxes, or qualifying for utility incentive programs to justify improving existing building envelope performance on the basis of energy only. The strength of the proposed methodology in Chapter 1 was in its balance of effort and ultimate decision-making utility, where reasonable thermal bridging approximations based on simulation models for existing buildings can yield data accurate enough to inform a ranking exercise on a large breadth of subject buildings. However, since numerical models do not consider degradation of building materials, real moisture content, and errors associated with manufacturing and installation, actual building envelope thermal performance differs from 3D simulation models. To study this limitation, in-situ thermal assessments of building envelopes were performed to quantify their actual thermal performances. To this end, Chapters 2 to 4 of this dissertation attempted to determine the viability of an external infrared thermography (IRT) survey technique for quantification of heat losses through the opaque building envelope, and also explores its potential application in identifying and comparing sources of air leakage. The experiments were performed on wood-framed wall assemblies commonly used in Canada due to growing interest among designers, builders, and governments to encourage the use of wood as a building material. In these studies, (Chapter 2 to Chapter 4), thermal transmittances (U-values) of wall assemblies were estimated with external IRT and compared with 3D computer simulations. Furthermore, the impact of the accuracy of U-values estimated with IRT on the deviation of energy simulation outputs with metered data was examined. Finally, a novel relative quantitative infrared index (IRI) was proposed as a means to facilitate rapid evaluation and subsequent ranking of building envelope thermal performance. From the experiments in Chapters 2 & 3, it was found that the U-values obtained with IRT were comparable with simulated values suggesting IRT can be a reliable tool for estimating the thermal performance of wood-framed wall assemblies. Results also demonstrated that thermal imaging artefacts including nonlinear characteristics of infrared (IR) camera focal array, a.k.a. non-uniformity corrections (NUC) and vignetting could have a substantial influence on the accuracy of results, in particular energy model outputs. This limitation was resolved by introducing a practical approach where thermal images were taken from different incident angle. Overall, IRI was found to be a reliable metric for relative quantitative comparison of building envelope thermal performance regardless of boundary conditions. Moreover, outcomes of the IRT air leakage study in Chapter 4 indicated that combined qualitative and quantitative IRT approaches could potentially be implemented by practitioners to identify sources of air leakage and thermal bridges in buildings and compare their relative severity. Since blower door testing is gradually being introduced as a building code requirement to measure building envelope airtightness in an increasing number of Canadian jurisdictions, performing IRT simultaneously is potentially valuable exercise in this context. Ultimately, the methodologies outlined in Chapters 2 to 4 can help decision-makers to characterize building envelope retrofits from a performance perspective, and potentially serve as a basis for governments to develop policies to improve existing building energy performance. The methodologies in Chapters 2 to 4 prompted opportunities to utilize the emergent technology of small unmanned aerial vehicles (UAVs) equipped with an infrared camera for quick thermal assessments of building envelopes. The last chapter of this dissertation, Chapter 5, outlines advantages and limitations of aerial IRT (UAV-IRT) surveys compared to conventional stationary IRT. Furthermore, a set of best practices for UAV-IRT were presented to minimize dynamic measurement uncertainty. It was concluded that with the current IR camera technology, aerial surveys for quantitative thermal assessment of building envelope are not as accurate as with conventional infrared thermography; further investigations by manufacturers and researchers are recommended. / Graduate
12

Lufttäthet och energiförbrukningi nyproducerade villor / Airtightness and energy consumption in newly produced villas

Svensson, Jonathan, Lagerqvist, Felicia January 2023 (has links)
Uppvärmning inklusive varmvatten i lokaler står idag för 53 % av Sveriges totalaenergianvändning. För att uppnå en del av de uppsatta energi- och klimatmålen för EU ärenergieffektivt byggande en viktig nyckel. De kraftigt stigande elpriserna de senaste årenär en annan anledning att bygga mer energieffektiva byggnader. Idag dokumenterasenergiförbrukningen i en energideklaration som registreras hos Boverket för att ge entydlig bild av energianvändningen. Med hjälp av en lufttäthetsprovning där byggnadenutsätts för ett över- och undertryck på 50 Pa fås ett mått för hur mycket luft som läckergenom klimatskalet.Målet med arbetet är att undersöka hur energiförbrukningen i energideklarationen kansättas i korrelation till luftläckagevärdet. Med utgångspunkt ur villor producerade avEksjöhus som är lufttäthetsprovade från 2019 till 2023, har detta arbete jämfört statistikför att få fram en korrelationskoefficient. För att få en förståelse för hur Eksjöhus arbetatmed lufttäthet studerades utvecklingen av klimatskalet och luftläckagevärdet från 2012till 2022 via intervju och statistikarbete. För ett urval av lufttäthetsprovade hus byggdamellan 2019 och 2023 begärdes energideklarationer ut. Ett statistikarbete för data urenergideklarationer och luftläckagevärde genomfördes som är underlaget för diskussionoch analys av energideklarationens reliabilitet för att göra en översiktlig tolkning avresultatet tillförlitlighet.I intervjun med Eksjöhus framgår det att den enda förändringen som skett i klimatskaletsedan 2012 är att vägg-bjälklaget placerats en bit längre in för att underlätta att dra förbiplastfolie. Förändringen ger inte en synlig påverkan av det generella luftläckagevärdet.Eksjöhus har arbetat fram ett dokument som skickas med byggsatsen och fungerar som enguide för entreprenörerna för hur tätningar kring stålbalkar, genomföringar ochanslutningar ska göras. Eksjöhus använder sig även av en årlig träff tillsammans med deentreprenörer som bygger de flesta husen för att arbeta med lufttäthet. Vid arbetet medlufttäthet har Eksjöhus procentuellt minskat antalet nybyggda hus där luftläckagevärdetöverstiger de krav/riktlinjer företaget har.För att undersöka om luftläckage visar på ökad uppvärmd energi genomfördes enkorrelationsstudie där två variabler sätts i korrelation till varandra. Studien är tänkt attvisa att om ett hus läcker mycket luft kommer mängden energi som går åt till att värmaupp huset att öka. I jämförelse mellan luftläckage och uppvärmd energi visar inte studiennågot generellt samband.Arbetet tar inte hänsyn till byggnadernas specifika förutsättningar. Det leder till utebliveninformation kring levnadsvanor, antalet brukare och innetemperatur. I övrigt användesenbart energideklarationer från 103 samt 107 byggnader som deklarerats tidigast 1 januari2019. Provtryckningsresultat för att undersöka hur arbetet med lufttäthet för Eksjöhusnyproducerade villor utvecklats begränsas från 2012 till 2022. / This study investigating the correlation between energy consumption in energydeclarations and air leakage values, with a focus on Eksjöhus-produced villas. Tounderstand how Eksjöhus has been working with airtightness during 2012 to 2022 aninterview and an analysis of statistic has been done.The aim of this work is to investigate how the energy consumption documented in energydeclarations can be correlated with the air leakage obtained through an air leakage test.The results suggest that Eksjöhus implemented a solitary modification to the buildingenvelope since 2012, which did not significantly affect the overall air leakage values.During the period there was a proportional decrease in the number of new housesexceeding Eksjöhus requirements/guidelines for air leakage.No general correlation was found between energy consumption and air leakage. Whensorting data for low energy consumption and low air leakage a clearer correlation wasfound. The result also shows an economic advantage of constructing buildings with highairtightness.
13

Determinação do coeficiente e expoente de escoamento em esquadrias nacionais, para análise de infiltração de ar em edificações

Santos, Henrique Zenker dos 21 October 2016 (has links)
Submitted by Silvana Teresinha Dornelles Studzinski (sstudzinski) on 2017-02-08T14:37:06Z No. of bitstreams: 1 Henrique Zenker dos Santos_.pdf: 9480964 bytes, checksum: 5a3a14f9704ce1135e84db57590283a7 (MD5) / Made available in DSpace on 2017-02-08T14:37:06Z (GMT). No. of bitstreams: 1 Henrique Zenker dos Santos_.pdf: 9480964 bytes, checksum: 5a3a14f9704ce1135e84db57590283a7 (MD5) Previous issue date: 2016-10-21 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Países desenvolvidos apresentam crescimento contínuo nas taxas globais de consumo de energia. Um dos fatores preponderantes está relacionado ao uso de condicionadores de ar para manutenção das condições de conforto no interior de edificações, onde tal parcela já atinge valores de consumo superiores aos dos setores de indústria e transporte. Sabe-se que o consumo devido ao condicionamento de ar afeta diretamente o desempenho energético e ambiental de uma edificação e, por conseguinte, a qualidade de habitação e de vida dos usuários. No Brasil este processo ocasiona um vertiginoso incremento nos gastos públicos, com inúmeras consequências de ordem econômica e social. Dados do Ministério de Minas e Energia indicam que 20% da energia consumida no país é destinada ao abastecimento de residências. Cenário este que tende a evoluir devido aos constantes lançamentos do mercado imobiliário, derivativos de planos habitacionais estimulados pelo governo federal (como o Minha Casa Minha Vida), em decorrência do déficit habitacional registrado no país. Atrelado a isso observa-se o baixo padrão construtivo das edificações e o emprego de materiais e esquadrias de qualidade igualmente diminutas, que acarretam em ineficiências de carga térmica. A taxa de infiltração em uma edificação é regida pela relação estabelecida por uma equação de lei de potência, caracterizada pela presença de um coeficiente de escoamento “C” e um expoente de escoamento “n” (geralmente da ordem de 0,667 [-]). Esta dissertação apresenta, para uma esquadria de alumínio, modelo de correr, o coeficiente de escoamento C = 0,028 [dm³/s.m.Pan] e o expoente de escoamento “n” 0,552 [-]. Para uma esquadria de PVC, modelo integrado, o coeficiente de escoamento C = 0,022 [dm³/s.m.Pan] e o expoente de escoamento “n” 0,605 [-]. / Developed countries have continued growth in global energy consumption rates. One of the most important factors is related to the use of air conditioners to the comfort conditions inside buildings’ maintenance, which such a part already reaches consumption values higher than the industry and transportation sectors. It is known that consumption due to air conditioning directly affects the energy and environmental performance of a building and therefore the house’s quality and the people’s life. In Brazil, this process leads to a big increase in public spending, with many consequences of economic and social order. Information from the Ministry of Mines and Energy indicate that 20% of the energy consumed in the country is used for supplying homes. This scenario tends to evolve due to the constant housing market releases, derived from housing plans stimulated by the federal government (such as “Minha Casa Minha vida”), in consequence of the housing deficit registered in the country. Related to this, it is observed the low construction standards of buildings and the use of materials and frames of low quality that lead to thermal load inefficiencies. Engineers and architects spend a part of their activities in creating scenarios for evaluating the thermal load calculation and vulnerability due to the influence caused by air infiltration into the environment. The infiltration rate of a building is managed by the established relationship by a power law equation, which is characterized by a flow coefficient "C" and a flow exponent "n" (usually on the value of 0.667 [-]). This work shows for an aluminum window, sliding template, the flow coefficient C = 0.028 [dm³/s.m.Pan] and the flow exponent "n" 0.552 [-]. For PVC window, integrated model, the flow coefficient C = 0.022 [dm³/s.m.Pan] and the exponent flow "n" 0.605 [-].
14

Zabezpečování kvality pneumatických válců / Quality assurance of pneumatic cylinders

Pabiška, Martin January 2021 (has links)
This Master thesis deals with the requirements for the quality of ISO standard compliant pneumatic cylinders, which are machined and assembled by a local manufacturer. According to the philosophy of continuous improvement, this thesis describes the project to decrease the number of air leaks detected by automatic testing machines. The main benefits of the thesis are the improvement of the design of pneumatic cylinders and the improvement of their assembly procedure leading to a reduction in the number of air leaks from pneumatic cylinders on automatic test equipment. It also provides an overview and general procedure for selecting, analyzing, implementing measures and taking further opportunities to improve the quality management system of pneumatic cylinders in the company.
15

Undersökning av TRP tak med PIR isolering utan plastfolie / Investigation of TRP-roof construction with PIR insulation without plastic film

Pourfeiz, Hani, Karmanji, Yadgar January 2015 (has links)
Idag ligger fokus på energieffektivisering av byggnader. I och med detta ligger tung vikt på fuktsäkerhetsprojektering i konstruktioner som i sin tur måste vara lufttäta och diffusionstäta. Kombinationen av svenska vinterperioder och övertrycket som uppstår inomhus medför att taken utsätts för stora påfrestningar. Luften inomhus innehåller alltid mer fukt än luften utomhus. Då fukt alltid strävar efter att jämna ut sig går den varma och fuktiga inomhusluften till utrymmen med lägre fukthalt eller lägre lufttryck. Det är bland annat av dessa anledningar man använder ångspärr i ytterväggar och takkonstruktioner. Syftet med detta projekt är att genomföra en fuktteknisk bedömning för takkonstruktioner uppbyggda av TRP plåt, PIR isolering utan plastfolie. Anledningen till att bygga tak utan plastfolie är att sätta fuktfrågorna i fokus vid nybyggnadsprojekt samt att eftersträva skapandet av fuktsäkra och sunda konstruktioner. För att analysera takkonstruktionen samt genomföra fukttekniska bedömningar har simuleringar av konstruktionen under olika förutsättningar i WUFI Pro 5.1. genomförts. Därefter har resultatet analyserats ur diffusions- och konvektionssynpunkt. Resultaten visar inga större skillnader ur diffusionssynpunkt. Dock är skillnaderna mer uppenbara ur konvektionssynpunkt. Fuktmängden i konstruktionen utan plastfolie var betydligt större än konstruktion med plastfolie. Resultaten visar på att luftläckaget och fuktmängden har ett proportionellt förhållande med luftspaltbredden som bildas mellan PIR isoleringselementen. Detta gäller om ingen plastfolie används i konstruktionen. Slutsatsen är att det råder en större risk för luftläckage hos takkonstruktionen utan plastfolie på grund av otätheter i skarvar och spalter. För att få en fuktsäker och sund konstruktion rekommenderar författarna att plastfolie används. / Nowadays there is a high focus on energy efficiency of buildings. Therefore, a lot of resources are dedicated to moisture management in order to ensure that constructions stay airproof and diffused.  The combination of Swedish winter periods and the overpressure that occurs indoors means that the ceilings are subjected to the great stress. Indoor air contains more moisture than the air outdoors. As moisture is always striving to even out, the hot and humid indoor air moves to spaces with lower moisture content or lower air pressure. It is partly for these reasons why it is necessary to use a vapor barrier in the outer wall and roof construction. The purpose of building roofs without plastic foil is to put moisture issues in focus for new construction projects, but also, seek to create moisture proof and healthy construction designs. Further the goal of this project is to conduct a moisture technical assessment of roof structures built by TRP plate and PIR insulation without plastic film. Additionally, investigate if PIR-insulation can act as diffusion and convection protection. In order to analyze the roof structure and conduct moisture technical assessments, the design has been simulated using WUFI Pro 5.1 during different conditions. The result has then been analyzed from diffusion and convection perspectives. The results showed no major differences when compared from diffusion point of view. However, the differences are more obvious from convection perspective. The amount of moisture in the construction without plastic foil was considerably larger than the construction with a plastic foil. The results also showed that the air leakage and moisture amount has proportional ratio to the air gap width between the PIR-insulation elements. This is the case if no plastic foil used in the construction. The conclusion is that there is a greater risk of air leakage in the roof construction without the plastic foil because of leaks in the joins or gaps. For a moisture-proof and healthy design, the authors recommend that a plastic foil should be used.

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