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Sökning: WFRF:(Wahlgren Paula 1967)

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1.
  • Femenias, Paula, 1966, et al. (författare)
  • Energirenovering av flerfamiljshus uppförda före 1945: De boendes perspektiv
  • 2018
  • Ingår i: Bygg och teknik. - 0281-658X. ; 2018:5, s. 10-15
  • Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
    • Under 1970-talet täcktes originalfasaderna på många äldre flerfamiljshusav material som krävde mindre underhåll såsom plåt och skivmaterial i samband med tilläggsisolering. Idag står dessa byggnader inför nya renoveringar med högre krav på energiprestanda. Denna studie berör två bostadsområden där man planerar eller nyligen har genomfört en omrenovering. Med omrenovering menar vi en större renovering för energieffektivisering och där möjligheten finns för återskapande av värden som gått förlorade i tidigare renoveringar. Enkäter och intervjuer med boende genomfördes för att svara på frågorna: Hur ser de boende på renoveringarna? Vilken betydelse har byggnadernas historia och kulturhistoriska värden för dem? Vilken betalningsvilja finns för energibesparing, inomhuskomfort och kulturvärden?
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2.
  • Femenias, Paula, 1966, et al. (författare)
  • Om-renovering – möjligheter för energieffektivisering när äldre flerbostadshus renoveras en andra gång
  • 2019
  • Ingår i: Bygg och teknik. - 0281-658X. ; 2019:2, s. 24-28
  • Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
    • Byggnader har av EU [1] pekats ut som den enskilt största sektorn för att spara energi och minska utsläppen av växthusgaser. De största vinsterna finns att hämta i den befintliga bebyggelsen och EU föreslår strategier med omfattande renovering för att uppnå målen. I det här forskningsprojektet har flerfamiljshus uppförda före 1945 studerats. Många har redan varit renoverade med tidigare energibidrag och då förvanskade vad gäller ursprungliga arkitektoniska värden, men står nu inför nya behov av renovering. Tre frågor har varit i fokus: Vad finns det för information om de här byggnaderna? Vilken information behövs för att skapa strategier för hur de kan renoveras? Vad finns det för möjligheter att energieffektivisera samtidigt som kulturvärden bevaras eller till och med återskapas i en andra större renovering?
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3.
  • Femenias, Paula, 1966, et al. (författare)
  • Om-renovering: Möjligheter för energieffektivisering och återskapande av kulturvärden när flerbostadshus renoveras på nytt
  • 2020
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • Projektet har undersökt möjligheterna att återskapa estetiska och historiska karaktärsdrag av flerbostadshus som blivit förändrade i samband med tidigare energisparprogram samtidigt som nya energieffektiviseringar kan genomföras, en process som vi valt att kalla för om-renovering. En om-renovering skapar möjligheter för energieffektivisering men också att uppnå mål om en god bebyggd och gestaltad livsmiljö. Projektet har studerat om-renovering ur ett helhetsperspektiv vilket inkluderat energibesparingar, arkitektur och kulturvärden, genomförbarhet samt sociala värden. Studien har fokuserat på flerbostadshus uppförda före 1946 i Göteborg. Flera metoder och angreppsätt har använts i fyra delstudier. En första delstudie var en inventering av ungefär en tredjedel av flerbostadshusen uppförda före 1946 i Göteborg. Målet var att undersöka hur husen har renoverats och deras status idag, med fokus på yttre synliga ändringar. Till inventeringen lades information från energideklarationer om energiprestanda vilket gjort det möjligt att undersöka samband mellan energiprestanda och renoveringar. Inventeringen visar att det är svårt att fastställa generella samband mellan tidigare renoveringar och energiprestanda med de sammanställda data. Slutsatsen är att inventeringar på fastighets- eller byggnadsnivå är nödvändiga för att ta rätt beslut vid nya energieffektiviseringar. I en andra delstudie gjordes fallstudier av fyra fastigheter med landshövdingehus, tre som omrenoverats och en som genomgått en första större renovering. Fallstudierna beskriver motiv för återställande av träfasader och ambitioner för energibesparingar. Det finns inga krav på återställande vid bygglov. De motiv som framkommer pekar istället på ekonomiska och estetiska drivkrafter för om-renoveringar. Energieffektivisering var bara ett uttalat mål i ett fall och energibesparingarna blev lägre än vad som krävs för att uppnå våra svenska energimål. Om-renoveringarna är en kompromiss mellan vad som uppfattats som estetiskt tilltalande och vad som varit ekonomiskt eller tekniskt genomförbart. Översyn från myndighetshåll av energieffektiviseringar och kulturvärden framstår som bristfällig. En tredje delstudie har studerat de boendes syn på kulturvärden i boendemiljön i tre av de ovan nämnda fallen. Studien visar ett statistiskt samband mellan trivsel och uppskattning av kulturvärden. De boende känner till sitt hus’ historia och uppskattar den. En del boende, särskilt de som bott länge på samma ställe, har en egen relation till husets och områdets historia. För andra, här representerat av flera yngre som bor i en äldre fastighet, är äktheten inte lika viktig vid ett återskapande som atmosfären. Slutligen, i en fjärde delstudie undersöktes energi- och klimatpåverkan från om-renoveringen i en av fallstudierna. Studien pekar på att återbetalningstiden för den inbyggda energi- och klimatpåverkan är strax under 25 år och därmed kortare än livslängden för material och komponenter som använts (om renoveringen antas ha en livslängd på 50 år). En jämförelse mellan en återställd träfasad och en fasad med moderna fibercementplattor är till träfasadens fördel ur ett klimatperspektiv men inte vad gäller inbyggd energi. Rapporten avslutas med rekommendationer för konsulter, fastighetsägare och handläggare på kommuner och andra myndigheter som arbetar med frågor kring om-renovering.
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4.
  • Femenias, Paula, 1966, et al. (författare)
  • Renovating the Housing Stock Built Before 1945: Exploring the Relations Between Energy Efficiency, Embodied Energy and Heritage Values
  • 2018
  • Ingår i: Springer Proceedings in Energy: Cold Climate HVAC 2018, Kiruna, Sweden, 12-15 March, 2018. - Cham : Springer International Publishing. - 9783030006617 - 9783030006624 ; , s. 291-301
  • Konferensbidrag (refereegranskat)abstract
    • Swedish multi-family buildings constructed before 1945 constitutes an important part of the national built heritage. However, the majority does not have a formal heritage protection. Part of this building stock has already been renovated, notably through earlier energy saving programmes where additional exterior insulation, new façades and windows were frequently installed with little consideration for the original architecture. Now, 40 years later, these buildings face new renovations. This provides opportunities to improve the energy efficiency, indoor climate and user comfort. At the same time, the original architectural and historical characters lost in previous renovations could be recreated. In this paper, an inter-disciplinary research team illustrates the challenges met in practice to reach a sustainable renovation based on three cases. The case buildings are so-called "Landshövdingehus”, constructed in the 1930s and owned by a public housing company. The relations between building physics, energy efficiency, embodied energy, and the effect on heritage aspects in renovation are studied. The results demonstrate the potential to reach 30% calculated energy efficiency without investing in ventilation systems. When comparing embodied energy to savings in operational energy a short payback time is achieved. However, focusing on the replacement of windows, the cases illustrate difficulties to recreate heritage values at same time as achieving an air-tight and energy efficient construction. In order to improve the results from a heritage point of view, there is a need for quality assurance of the renovation and building permit process.
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5.
  • Femenias, Paula, 1966, et al. (författare)
  • Renoveringsbehov i äldre hus: möjligheter för energieffektivisering och bevarande av kulturmiljö
  • 2017
  • Ingår i: Bygg & teknik. ; 2017:2, s. 32-37
  • Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
    • Många av våra äldre flerbostadshus behöver moderniseras och renoveras inom de närmaste åren. Ofta handlar det då om byggnader som redan är renoverade och skall genomgå en andra större renovering. Vid renovering av äldre flerbostadshus behöver bevarande av kulturmiljö beaktas. Frågan är hur man kan modernisera för dagens krav på bland annat energieffektivitet samtidigt som den ursprungliga kulturmiljön bevaras eller till och med återskapas? Även de boendes prioriteringar och betalningsmöjligheter är en starkt påverkade faktor.
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6.
  • Femenias, Paula, 1966, et al. (författare)
  • Value creation by re-renovation – focus on the user perspective
  • 2018
  • Ingår i: Proceedings of the 3rd International Conference on Energy Efficiency in Historic Buildings, EEHB2018. ; , s. 172-181
  • Konferensbidrag (refereegranskat)abstract
    • Historic multi-residential buildings that have been renovated at an earlier occasion are today facing new interventions. Re-renovation defines a concept for a second major renovation which opens up for the possibility of re-creating architectural and heritage values that has been lost in earlier renovations at the same time as demands for modernisation, energy efficiency, and economy are met. This paper focuses on what values heritage and historic buildings represent for residents, how they perceive the effects of energy renovation, what building elements they appreciate, and the implications for carrying out re-renovation. An empirical study of two cases with rental and owner-occupied housing has been applied combing a questionnaire survey (n= 83) and interviews (n=9). Findings indicate that historic buildings create values for their residents which should be considered by property owners when planning a renovation or re-renovation. Methodologically, asking residents about heritage values is challenging and the paper provides suggestions for further research in the field.
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7.
  • Jerome, Adeline, 1994, et al. (författare)
  • Exploring the Relationship between Environmental and Economic Payback Times, and Heritage Values in an Energy Renovation of a Multi-Residential Pre-War Building
  • 2021
  • Ingår i: Heritage. - : MDPI AG. - 2571-9408. ; 4:4, s. 3652-3675
  • Tidskriftsartikel (refereegranskat)abstract
    • Cultural value and heritage have been identified as necessary for a sustainable living environment, alongside environmental concern and energy efficiency. In this study, multiple methods, i.e., life cycle assessment, payback, and questionnaires and interviews with tenants, and empirical data from a recent energy renovation of a multi-residential pre-war building with wooden construction were used to analyse the impact of the renovation on cultural and aesthetic values, environmental impact, financial payback time, and user satisfaction. In the energy renovation, the façade, which had been disfigured in an earlier renovation, was recreated to resemble the original architecture. The main questions are: What impact has the recreation of the façade on the environmental payback time in comparison to a more conventional renovation? What are the consequences for the user satisfaction and financial return on investment? The results show that the recreated façade has improved the building’s aesthetics without compromising the environmental benefits. It also resulted in better thermal comfort, which is highly valued by the tenants. The improved aesthetics are also appreciated by the tenants, but to a lesser extent. Financially, the renovation is estimated to be not viable. Results of this study can be applied in the decision-making of similar renovation projects
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8.
  • Johansson, Pär, 1986, et al. (författare)
  • Pending for Renovations: Understanding the Conditions of the Multi-family Housing Stock from before 1945
  • 2016
  • Ingår i: Energy Procedia. - : Elsevier BV. - 1876-6102. ; 96, s. 170-179
  • Konferensbidrag (refereegranskat)abstract
    • The Swedish housing stock is once again in focus for national energy savings, as it was after the oil crises in the 1970s and 1980s. The contemporary debate has a one-sided focus on energy savings and barriers for implementation of existing energy efficient renovation measures but also on large stock of industrialized housing built after 1960. The need for renovation is equally urgent in older stocks of housing, also in those that already have been renovated but are in need for further interventions. In this paper we focus on multi-residential housing built before 1945 in Gothenburg, Sweden, representing cultural and historical heritage values. The opportunities to ensure high energy efficiency with new measures in a second renovation should aim to find a balance with heritage values, social values, function, aesthetics and management aspects. In order to get an understanding of the conditions of the stock in focus, we apply both a top-down and bottom-up approach. In the top-down approach, data are gathered from different sources such as energy performance certificates, the national property register, and geodata from the City of Gothenburg. By combining information from these databases, three data subsets have been defined for the bottom-up approach: non-renovated buildings, buildings renovated to a small extent and buildings renovated to a large extent. Three case study buildings were selected out of these data subsets. The choice of renovation strategy differs between the cases. Case study building 1 has been left virtually untouched while case study building 2 and 3 have been renovated to different extent. The next step in this research project is to identify suitable renovation alternatives for these building typologies.
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9.
  • Andersson, Patrik, 1974, et al. (författare)
  • Framtidsbilder för samhällsbyggnad
  • 2006
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • Framtidsbilder för samhällsbyggnad 2020De kommande 15 åren står institutionen för Bygg- och miljöteknik inför stora förändringar. Därför har institutionen initierat projektet Framtidsbilder 2020 där man engagerat en framtidspanel bestående av elva yngre disputerade forskare. Arbetet inleddes med ett breddgruppsmöte där 110 personer representerande institutionens personal och studenter deltog. Vid mötet identifierades ett antal trender och osäkra utvecklingar som påverkar framtiden inom samhällsbyggnadsområdet. Deltagarna bidrog också med idéer till en önskvärd utveckling, vilket har sammanställts och utgör grunden till en gemensam önskvärd framtid/vision för institutionen. Materialet från breddgruppsmötet har bearbetats av Framtidspanelen och resulterat i fyra scenarier som beskriver hur samhällsbyggnadsområdet kan se ut år 2020. Syftet med framtidsbilderna är att de ska vara vägledande för institutionens beslut och förhållningssätt under de kommande åren.Fyra scenarierTurning TorsoSamhället präglas av en ekonomi som är på uppgång, och av ett nytänkande och öppet samhälle. Materiell status och individualism är viktigt. Detta leder till en hög arbetsbelastning samt krav på exklusiva varor av hög kvali-tet. Det finns en stor medvetenhet om miljöpåverkan och klimatförändringar och lösningarna för att klara energiförsörjningen är innovativa.Eco-metropolenDet sveper en grön våg genom dagens samhälle. Under de senaste 15 åren har vi insett att jorden skall vara en bebolig plats även åt dem som kommer efter oss. Vi söker ständigt efter nya, mer förfinade metoder att tillvarata de resurser vi har. Samhället och individen är i balans. Ekonomin är god och vi är miljömedvetna, trygga och integrerade. Nytänkande premieras och icke- materialistiska värderingar står högt i kurs. Vi tänker individuellt, men agerar mer än gärna för kollektivets bästa. Utbildning är gratis TrädgårdsstadenEtt samhälle där vi lärt oss hantera stress, men känner oss otrygga och helst umgås i slutna sociala sammanhang. Vi bor enkelt inne i stan, eller gärna på landsbygden nära storstäderna. Minskade behov av högutbildade i samhället gör att vi har svårt att rekrytera studenter till teknikutbildningar. Det traditionella tankesättet leder till kulturkrockar med företag och personer från andra länder.Gated communitiesFörsämrad ekonomi och ökad egoism har lett fram till ett stressat, otryggt och segregerat samhälle. Accelererande klimatförändringar och ökad miljö-påverkan skrämmer oss, men trots det åtgärdar vi inte problemen, utan koncentrerar oss på konsekvenserna. Arbetslöshet i samhällsbyggnadssek-torn leder till sänkt status för samhällsbyggaren. Vi har därför svårt att rekrytera studenter, och även forskningen har låg status.
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10.
  • Berge, Axel, 1983, et al. (författare)
  • Changing internal pressure to achieve variable thermal conductivity in thermal insulation
  • 2015
  • Ingår i: Advance building skins: Proceedings of the International Conference on Building Envelope Design and Technology. - 9783851253979 ; , s. 309-316
  • Konferensbidrag (refereegranskat)abstract
    • Cold climates might have a variable need for thermal insulation. When there are large heat loads a low Uvalueis preferable, and opposite when heat loads are low and it is cold outdoors. One way to adjust the Uvalueis to change the gas pressure within the insulation. This would be especially effective in nano-porousmaterials where the relation between pressure and thermal conductivity is stronger. Measurements have beenconducted on an aerogel blanket and a fumed silica material. The results show an almost linear dependencein thermal conductivity at pressures between 1 kPa and 100 kPA for both materials. In the measurements,the thermal conductivity increase by a factor between 1.5 and 2.6 (highest conductivity divided by lowestconductivity).
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11.
  • Berge, Axel, 1983, et al. (författare)
  • Effect from a Variable U-Value in Adaptive Building Components with Controlled Internal Air Pressure
  • 2015
  • Ingår i: Energy Procedia. - : Elsevier BV. - 1876-6102. ; 78, s. 376-381
  • Konferensbidrag (refereegranskat)abstract
    • A variable U-value would be beneficial for a buildings thermal performance. One way to switch the U-value of a wall, insulated with nano-porous material, is to change the internal pressure of the insulation This paper present thermal conductivity measurements showing a possible variation around of 3 times for a fumed silica and less than 2 times for an aerogel blanket when the pressure was varied between 1 and 100 kPa. The variation factor of 3 was used in building energy simulation of a Swedish office showing that a U-value which can be varied within that range can give a significant reduction energy demand. Especially when energy used for cooling is weighted as worse than energy used for heating.
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12.
  • Berge, Axel, 1983, et al. (författare)
  • Wooden stud walls with aerogel thermal insulation. Material properties and HAM-simulations
  • 2013
  • Ingår i: Thermal Performance of the Exterior Envelopes of Whole Buildings - 12th International Conference 2013.
  • Konferensbidrag (refereegranskat)abstract
    • This study evaluates the heat and moisture performance of wooden stud walls with aerogel blankets as the main insulation.There is always a risk that a newmaterial will create problems if it is applied in the same way as conventional materials.To predictand prevent such problems, it is of essential interest to analyze aerogel applications from a heat and moisture perspective. In thisstudy, thermal conductivity and the vapor diffusivity of aerogel blankets were measured. The work found that the aerogel blanketscan be compressed and that compression actually lowers the thermal conductivity. The measured results were used as input innumerical simulations. Four different wall layouts were modeled and compared to a wall with conventional insulation. The simulationsshowed that the thickness of a wooden stud wall could be decreased to 60% with aerogel blankets instead of conventionalinsulation, with the same thermal transmittance. Also, the position of the aerogel layers had a large influence on the moisturecondition in the wall. The aerogel wall in the study with the best moisture performance has a homogeneous aerogel layer outsideof the wooden studs and the studs are in line, forming a continuous thermal bridge through the wall. The moisture performanceof the best aerogel wall in the study was as good as the studied wall with conventional insulation.
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13.
  • Bunkholt, Nora Schjoth, et al. (författare)
  • Experimental Study of Thermal Buoyancy in the Cavity of Ventilated Roofs
  • 2020
  • Ingår i: Buildings. - : MDPI AG. - 2075-5309. ; 10:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Pitched wooden roofs are ventilated through an air cavity beneath the roofing in order to remove heat and moisture from the roof construction. The ventilation is driven by wind pressure and thermal buoyancy. This paper studies ventilation driven by thermal buoyancy in the air cavity of inclined roofs. The influence of air cavity design and roof inclination on the airflow is investigated. Laboratory measurements were carried out on an inclined full-scale roof model with an air cavity heated on one side in order to simulate solar radiation on a roof surface. Equipment to measure temperature was installed in the roof model, while air velocity in the cavity was determined by smoke tests. Combinations of different roof inclinations, air cavity heights and applied heating power on the air cavity top surface were examined. The study showed that increased air cavity height led to increased airflow and decreased surface temperatures in the air cavity. Increased roof inclination and heating power applied to the roofing also increased the airflow. The investigations imply that thermal buoyancy in the air cavity of pitched roofs could be a relevant driving force for cavity ventilation and important to consider when evaluating the heat and moisture performance of such a construction.
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14.
  • Crona, Kajsa, et al. (författare)
  • Att gestalta och kommunicera energieffektiva byggnader bortom traditionella rum för lärande
  • 2011
  • Ingår i: NU2010, Sveriges universitets- och högskoleförbund, Stockholms universitet..
  • Konferensbidrag (refereegranskat)abstract
    • Arkitektur och teknik: att gestalta och kommunicera energieffektivitet bortom traditionella rum för lärandeInom utbildningsprogrammet för Arkitektur och teknik (AT) vid Chalmers tekniska högskola möts ingenjörskonstens och arkitekturens teorier, metoder och verktyg när arkitekturinriktade kurser varvas med teknikämnen. Allt sedan sin tillblivelse (lå 2006/2007) har programmetmycket tydligt strävat efter att finna former för att förnya och fläta samman de båda utbildningskulturerna, bland annat genom att förstärka AT-studenternas generellakompetenser med t.ex. språkutbildning. Resultatet har blivit en mix där några utpräglat ingenjörsvetenskapliga kurser med inslag av fackspråk kombineras med kurser och projekt inom arkitektur.Efter en rad försök att integrera de konstnärliga, ingenjörsmässiga och språkliga aspekterna har vi i år nått fram till en kombination av byggnadsfysik och arkitektonisk gestaltning som sträcker sig över en hel termin och där också fackspråk spelar en central roll. Uppgifteninnebär att studenterna arbetar fram och kommunicerar en energieffektiv och fuktsäker byggnad med hög nivå på bostadskvalité, gestaltning och professionellt språkbruk. Till förväntningarna på den här lärandemiljön hör till exempel att studenterna borde kunna uppnå och visa prov på en konstnärlig process baserad på ingenjörskunskap och att de ser och formulerar en helhet där systemlösningar går hand i hand med ett relevant formspråk.En viktig komponent inom arkitektutbildning är den så kallade kritiken - en kommunikativ och krävande examinationsform som innebär att studentens arbete presenteras, kritiseras och diskuteras med andra studenter och yrkesverksamma arkitekter och konstruktörer. Den härexaminationsformen dominerar den traditionella arkitektutbildningen och används med självklarhet i de kurser på AT-programmet som faller inom ramen för arkitektur. De kurser som präglas av ingenjörstraditioner och utbildningskulturen inom V-ingenjörsområdetexamineras som regel främst genom tentamina och konstruktionsuppgifter. Under vårterminen i åk 2 tenteras däremot kurserna Byggnadsfysik (V) samt Byggande och miljö(A) i form av en tvärdisciplinär och gemensam kritik, där även språkbruk och textlig gestaltning lyfts fram som komponenter.Syftet med vårt bidrag är att utifrån denna integrerade kritik diskutera vad det innebär för AT-studenterna att gå bortom traditionella rum för lärande. Med utgångspunkt från hur studenterna gestaltar energieffektivitet resonerar den här presentationen kring följande frågor:• Hur använder sig studenterna av kritiken som en resurs för att förmedla sin lösning som helhet betraktad?• På vilka sätt blir en förnyad men traditionellt präglad examinationsform ett hinder eller en möjlighet för AT-studenter?• I vilken utsträckning utvecklar studenterna sin roll som konstnärlig arkitekt med ingenjörsmässigt angreppssätt genom en integrerad examination av det här slaget?
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15.
  • Crona, Kajsa, 1972, et al. (författare)
  • Glazed spaces for a resource efficient, social and healthy living, Part 1. Inventory of geometries and functions by study visits and interviews
  • 2021
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • The main aim of the Spaces project is to support architects in the design of well-functioning glazed geometries, such as atria and rooftops, in residential buildings. The studied geometries are primarily spaces for communication and leisure in residential buildings. These spaces may have a varying indoor climate, which is governed by the construction of the building, as well as residents’ activities, rather than by building services. The project contributes with examples of geometries and usages, methods to evaluate the performance early in the design process and to provide guidance for architectural design and increased social interaction. The project also investigates obstacles that exist in current practice and Swedish legislation for glazed geometries. In this report, the first part of the project “Inventory of geometries and functions by study visits and interviews” is presented. Methods used in this first part is literature studies, interviews and case studies. The topics investigated are social and human aspects, technical aspects such as thermal comfort, energy, air quality, humidity, acoustics and to some extent urban farming. From the literature and by contacting architects and consultants in the building industry, eight case study buildings were found, located. The buildings were either housing cooperatives or rental buildings, and the glazed spaces in the buildings were either atria, glazed balconies or glazed rooftops. For the case studies, information was gathered from databases, through interviews and during study visits. The opinions of the residents were captured during structured interviews and through quantifiable surveys, and the results were analysed by the project group with input from the reference group. For social interaction, the investigations show that even with a developed design for social interaction (such as common areas, kindergarden, private areas in connection with glazed space), the interaction might fail. Social activities are highly dependent on individuals and thus, engaged persons are very valuable to obtain a social environment. In addition, a clear purpose of the space and a sense of ownership is beneficial to the social environment. In this study, the projects that worked well socially were the four housing cooperatives and one rental building. The three projects that worked less well were all rental. There are slightly different opinions of the optimal size to achieve social interaction. The architect of one of the projects that works well socially suggests a maximum of 60 persons (25-30 families) and at another socially successful building, there are 48 apartments. Two out of the three largest buildings (71 apartments and 126 apartments) did not function well socially. Daylight levels are usually considered good in the glazed spaces. However, there are darker areas, in particular under access balconies, and this also affects the daylight levels in the apartments. The air quality is usually perceived as good in the glazed spaces and the most common problem connected to air quality is a high level of moisture in the air, which can result in condensation on windows. For thermal comfort, the expected level of comfort is important for the experience of the space. If the space looks like it is indoor, the expectation is room temperature in wintertime and, consequently, people are disappointed if it’s much colder. Both studied rooftops have problems with high temperatures in summertime. The temperature in the glazed space depends to a large degree on shading and ventilation, but also on the thermal mass of the materials in the glazed space. This is further investigated in part 2 of the project (Wahlgren et al. 2021), where also evaluation tools and design guidelines are presented.
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16.
  • Domhagen, Fredrik, 1987, et al. (författare)
  • Air leakage variations due to changes in moisture content in wooden construction- magnitudes and consequences
  • 2017
  • Ingår i: Proceedings AIVC38th AIVC Conference, Nottingham, United Kingdom, 2017.
  • Konferensbidrag (refereegranskat)abstract
    • The airtightness of buildings is important for several reasons, such as being a prerequisite for low-energy buildings and for a healthy indoor air quality (without i.e. mold or radon). The airtightness of buildings can vary over time and investigations are made on these variations due to moisture induced movements in wooden constructions, and subsequent consequences, using both measurements and numerical simulations. Measurements were performed in a wooden guest house that was built in a laboratory hall with an approximate relative humidity of 30 %. The guest house was designed with a wind barrier but without a moisture barrier, and with a majority of the leakages situated in the wall/floor connection. The relative humidity in the guest house was varied so that the indoor relative humidity was kept at 90 % during 8 days and then decreased to 25 % during 7 days. This variation in moisture content in the wooden part can also illustrate the built in moisture in construction timber (starting at a moisture content of 16%). The air permeability was measured frequently during both periods and showed a change in air permeability from 0.74 l/sm2 to 1.21 l/sm2 at 50 Pa pressure difference. Consequently, for a wooden construction with a moisture dependent air permeability, it is easier to fulfill airtightness demands (checked by measurements), when the building is just erected, compared to a couple of months later. Numerical simulations on the moisture induced leakage variations and the impact of the resulting variation in air permeability are performed in Simulink and MATLAB. Air leakage is calculated using a set of object oriented functions within the MATLAB environment. These functions follow the same mathematical principle as presented in the airflow simulation software CONTAM. The simulations are made for the climate of Gothenburg in south-west part of Sweden.
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17.
  • Domhagen, Fredrik, 1987, et al. (författare)
  • Consequences of Varying Airtightness in Wooden Buildings
  • 2017
  • Ingår i: Energy Procedia. - : Elsevier BV. - 1876-6102. ; 132, s. 873-878
  • Konferensbidrag (refereegranskat)abstract
    • Previous research has shown that the airtightness in wooden buildings can vary over the year and that buildings can be less airtight during wintertime, likely caused by variations in humidity. In order to investigate possible causes and consequences, such as increased energy use and moisture damage, a number of numerical simulations and laboratory measurements have been performed. In a wooden guesthouse, without a moisture barrier, the indoor relative humidity is kept at 90 % during 8 days and then decreased to 25 % during 7 days. The airtightness is measured frequently during both periods and shows a change in airtightness from 0.74 l/sm2 to 1.21 l/sm2 at 50 Pa pressure difference. The moisture scenario can be related to common levels of inbuilt moisture as well as moisture loads from indoor activities. In order to investigate the consequences of varying airtightness, a numerical model is set-up to resemble a typical wooden detached house. Airflows and pressure profiles are then calculated for different values of airtightness. Simulations show that the total increase in exfiltration is dependent not only on airtightness value but also on leakage distribution. For example, exfiltration will increase with 1.9 % per percentage point of decrease in airtightness, if the distribution of leakages are concentrated to the lower parts of the building, compared to 1.6 % if leakages are more evenly distributed. Interestingly, results also show that if the cold attic is accessible through an attic hatch that is not airtight, air is likely to leak from the indoor environment to the attic during some periods of the year and downward to the indoor environment during other periods. Results show that variations in airtightness in wooden houses is affected by surrounding humidity and that the consequences of varying airtightness will affect both moisture and energy performance.
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18.
  • Domhagen, Fredrik, 1987, et al. (författare)
  • Contaminant Transport through the Thermal Envelope – Evaluation of Airflows Based on Numerical Modeling and Field Measurements
  • 2019
  • Ingår i: 14th International Conference on Thermal Performance of the Exterior Envelope of Whole Buildings.
  • Konferensbidrag (refereegranskat)abstract
    • The overall aim of this project is to improve the methodology for finding the cause for indoor air problems in schools. The methodology is improved by providing methods for determining if the contaminant source is within the building envelope as well as understanding how the pressure distribution is affected by ventilation, climate and airtightness. There is an urgent need for an improved methodology since many schools in Sweden today have unexplained indoor air quality problems. A numerical model has been developed that considers the influence that climate (wind speed, wind direction and temperature) and airtightness have on the air leakage in a building. The model is compared to measurements of pressure differences and weather data from a case study (a school building with documented indoor air problems). The analysis of the measurement at the school building shows that stack effect is an important parameter, even for a low-rise building. Wind pressure results in air flows both from and to the crawl space, primarily depending on wind direction combined with stack effect and air leakage distribution. Linear regression analysis of the measurement data proved to be a useful tool to detect anomalies in the measurements. A flow chart for an investigation procedure for air flows through the thermal envelope is presented in the paper.The overall aim of this project is to improve the methodology for finding the cause for indoor air problems in schools. The methodology is improved by providing methods for determining if the contaminant source is within the building envelope as well as understanding how the pressure distribution is affected by ventilation, climate and airtightness. There is an urgent need for an improved methodology since many schools in Sweden today have unexplained indoor air quality problems. A numerical model has been developed that considers the influence that climate (wind speed, wind direction and temperature) and airtightness have on the air leakage in a building. The model is compared to measurements of pressure differences and weather data from a case study (a school building with documented indoor air problems). The analysis of the measurement at the school building shows that stack effect is an important parameter, even for a low-rise building. Wind pressure results in air flows both from and to the crawl space, primarily depending on wind direction combined with stack effect and air leakage distribution. Linear regression analysis of the measurement data proved to be a useful tool to detect anomalies in the measurements. A flow chart for an investigation procedure for air flows through the thermal envelope is presented in the paper.
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19.
  • Domhagen, Fredrik, 1987, et al. (författare)
  • Impact of weather conditions and building design on contaminant infiltration from crawl spaces in Swedish schools—Numerical modeling using Monte Carlo method
  • 2022
  • Ingår i: Building Simulation. - : Springer Science and Business Media LLC. - 1996-8744 .- 1996-3599. ; 15:5, s. 845-858
  • Tidskriftsartikel (refereegranskat)abstract
    • Some Swedish school buildings built in the 1960s and 1970s experience indoor air quality problems, where the contaminants are suspected to come from the crawl space underneath the building. The poor indoor air quality causes discomfort among pupils and teachers. Installing an exhaust fan to maintain a negative pressure difference in the crawl space relative to indoors or increasing the ventilation in the classroom are two examples of common measures taken to improve the indoor air quality. However, these measures are not always effective, and sometimes the school building has to be demolished. The relation between pressure distribution, contaminant concentration in the classroom, outdoor temperature, wind, mechanical ventilation, and air leakage distribution is complex. A better understanding of these relations is crucial for making decisions on the most efficient measure to improve the indoor air quality. In this paper, a model for contaminant infiltration from the crawl space is used together with the Monte Carlo method to study these relations. Simulations are performed for several cases where different building shapes, building orientations, shielding conditions, and geographical locations are simulated. Results show, for example, that for a building with an imbalanced ventilation system, air is leaking from the crawl space to the classroom for the majority of cases and that concentration levels in the classroom are usually the highest during mild and calm days.
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20.
  • Domhagen, Fredrik, 1987, et al. (författare)
  • Method for Detecting Contaminant Transport through Leakages in a Condemned School
  • 2018
  • Ingår i: Proceedings of the 7th International Building Physics Conference, IBPC2018, Syracuse, NY, USA, 23-26 September 2018. - Syracuse, New York : International Association of Building Physics (IABP).
  • Konferensbidrag (refereegranskat)abstract
    • Many schools in Sweden, have problems with the indoor air, affecting the wellbeing and health of both pupil and teachers. Contaminants in the air, such as mold spores, radon, odors, and VOC, cause problems and it can be difficult to find the contaminant source, in particular if it is within the building construction. The aim of this project is to investigate air leakage paths and pressure differences in a school building with IAQ problems and to analyze how these parameters are related to contaminant transport. An increased knowledge of how contaminants are transported will then form the base for an improved strategy for dealing with renovations of schools with IAQ issues. The main method of investigation in this initial part of the project is blower door measurements and leakage paths detection. A method to use CO2 from dry ice as tracer gas for leakage detection is under development and tested in a condemned school building. Results presented in this paper show that it is possible to use this method to determine whether air leakages are coming from the crawlspace or from elsewhere.
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21.
  • Domhagen, Fredrik, 1987, et al. (författare)
  • Pressure distribution around the thermal envelope - a parametric study of the impact from wind and temperature on contaminant transport within a building
  • 2020
  • Ingår i: E3S Web of Conferences. - : EDP Sciences. - 2555-0403 .- 2267-1242. ; 173:11004
  • Konferensbidrag (refereegranskat)abstract
    • Several school buildings in Sweden have indoor air quality problems. The contaminant source is often  assumed  to  come  from  within  the  construction,  for  example  from  the  crawl  space  or  attic  space.  Contaminants,  in  these  cases,  are  transported  by  air  leaking  between  compartments  in  the  building.  Here,  the  driving  force  for  the  air  leakage  is  difference  in  pressure  and,  therefore,  determining  pressure  also  determines  the  direction  of  contaminant  transport.  In  many  cases,  measures  to  improve  the  air  quality  are  taken without a thorough understanding of how it might affect the pressure distribution in the building. In this  paper  a  numerical  model  is  used  to  examine  how  different  climate  scenarios  and  different  building  configurations affect the leakage and contaminant transport in a building with a crawl space. Results show that  for  leaky  buildings  the  ventilation  rate  increases  with  increased  wind  and  therefore  the  contaminant  concentration  decreases.  The  worst  scenario  in  terms  of  high  contaminant  concentration  is  mild  days  with  little  wind.  Also,  when  installing  an  exhaust  fan  in  the  crawl  space  with  the  purpose  to  prevent  air  from  leaking  from  the  crawl  space  to  the  classroom  it  is  advisable  to  also  consider  the  airtightness  and  the  climate, not only the pressure difference across the floor.
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22.
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23.
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24.
  • Johansson, Pär, 1986, et al. (författare)
  • Bevara och energieffektivisera kulturhistoriskt värdefull bebyggelse genom att använda superisoleringsmaterial
  • 2020
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • Syftet med projektet har varit att visa hur superisoleringsmaterial (SIM) kan användas för att spara energi och utrymme, samt bidra till bevarande av kulturhistoriskt viktiga inslag samtidigt som temperatur- och fuktförhållanden i väggar vid renovering i byggnader byggda före 1945 hålls på en säker nivå. Projektet har genomförts av forskare inom områdena byggnadsfysik och kulturvård. Tegelbyggnader i Sverige har varit huvudfokus eftersom det är dessa byggnader som har de största energieffektivitetspotentialerna i hela byggnadsbeståndet. Tegelbyggnader utmanar ofta ingenjörer och arkitekter genom att det ställs motsägande krav på energieffektivitet och bevarande av kulturvärden. Ofta har dessa byggnaders fasader värdefulla karaktärsbärande element som gör dem svåra att tilläggsisolera. Det finns också problem med de byggteknik, teknisk livslängd och bristande termisk komfort inomhus. Utvärdering av inverkan på kulturvärden har framförallt skett genom intervjuer och praktiskt arbete vid studiebesök och granskning av ritningar och bygghandlingar och har utförts av arkitekt och byggnadsantikvarie. Samarbetspartners, knutna till referensgruppen, bidrog till projektet med sin kunskap genom intervjuer, möten och seminarier. I samverkan med IEA EBC Annex 65 har information om olika superisoleringsmaterial och deras egenskaper sammanställts. Ett fullskaligt fältförsök i en övergiven tidigare industribyggnad från 1896 i Forsåkersområdet utanför Göteborg genomfördes. Ett mindre testrum byggdes upp inne i byggnaden invid ytterväggen av massiv tegel. Det genomsnittliga beräknade U-värdet minskade med 69% för 20 mm aerogelbaserad komposit (AB) och 80% för 20 mm vakuumisoleringspaneler (VIP), medan mätningar i testrummet gav en reduktion på 82-83% för AB och 81-84% för VIP. På byggnadsnivå skulle detta innebära att energianvändningen skulle kunna minskas med upp till 20%. Projektet har lett fram till en ökad kunskap om de tekniska svårigheter som finns vid bevarande av kulturvärden och energieffektivisering av byggnader med superisoleringsmaterial. Fördelarna med superisoleringsmaterial, särskilt flexibla material som aerogelfiltar, framgår när detaljer ska bevaras. På grund av de risker invändig tilläggsisolering av ytterväggar medför är det viktigt att först utreda om väggen tillåter invändig isolering, framförallt när det gäller fuktförhållanden i väggen.
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25.
  • Johansson, Pär, 1986, et al. (författare)
  • Deterioration in brick buildings: hygrothermal performance and measures to save them
  • 2020
  • Ingår i: E3S Web of Conferences. - : EDP Sciences. - 2555-0403 .- 2267-1242. ; 172
  • Konferensbidrag (refereegranskat)abstract
    • Many former industrial building sites in Sweden have been abandoned and left to deteriorate. Nowadays, there is a large interest to refurbish and retrofit these buildings for other purposes. Commercial and housing developers are attracted to these areas which are often in the outskirts of the city centers. There are several challenges facing architects and engineers to preserve these buildings, also connected to cultural heritage demands. The aim of this study is to propose measures to preserve cultural heritage buildings. A brick building in Gothenburg, on the Swedish west coast, is used as a case study. The building was used for paper production until 2005. After that, it deteriorated quickly after the heating was turned off. The rapid decay affected the hygrothermal performance as well as the load-bearing capacity of the structure. Small scale laboratory investigations of the building materials show a high degree of decay. Measurements of temperature and relative humidity is used to monitor the hygrothermal performance. Observations show that the brick masonry has heavy salt efflorescence and is in need of further protective measures.
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26.
  • Johansson, Pär, 1986, et al. (författare)
  • Differences between Measured and Calculated Energy Use in EPCs versus Building Permits. QUALICHeCK Report: "Status on the Ground" (New field study/2016)
  • 2016
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • In 2006, the Energy Performance Certificates (EPC) were implemented in the Swedish national building code. At the same time, the energy use demands in the building code (BBR) were transformed to be only performance based, i.e. a demand only on the maximum energy use. The country is divided in four climate zones, with the highest allowed energy use in the north and the lowest in the south. The EPCs are based solely on the measured energy use in the building. The regulation requires that the measured energy use is corrected to normal use during a reference year. However, there is no standardised methodology to account for normal use in the EPC and this is therefore seldom done. This study is focused on investigating the cause of differences between the calculated and measured energy use in buildings, in order to detect compliance problems with measured EPCs. Based on interviews, analysis of two databases with EPCs in single-family houses and multi-family buildings, complemented with energy use calculations, potential general procedures and parameters that cause these differences are identified and investigated. Suggestions on improvements to the Swedish EPC scheme are also presented. For new buildings, the regulation requires that the energy use is calculated and presented for the municipality in the building permit application. This calculation is most often based on early design drawings where limited knowledge is available on the technical properties of the building. Previous studies have shown that the variations on energy use caused by the occupants’ behaviour is often underestimated in energy use calculations. In single-family houses, differences in the occupants’ behaviour can account for up to 50% of the building’s energy use. In low energy houses the variation of the occupants’ behaviour has a larger relative impact on the energy use than for buildings with higher energy use. To rule out the possibility of failures in the construction and operation of buildings, the building process needs to be followed by measurements at regular intervals of e.g. airtightness. However, these measures are not enough to guarantee an energy use in line with calculations. Not only the occupants’ behaviour, construction and operation influence the measured energy use. It is also influenced by the location and number of energy use meters for heating, domestic hot water and facility electricity. For example, a previous study showed that unexpected heat losses in culverts in the heating distribution system increased the energy use in a multi-family building by 12.6%. Similar results were also described in the interviews. Two energy and climate advisors and two energy experts were interviewed in this study. They are involved in different stages of the design of buildings and follow-up of energy use in buildings. According to Boverket, around 90-95% of all the buildings sold in Sweden have a valid EPC. The regulation also requires that all new buildings have an EPC two years after commissioning. There are no national studies performed on this topic in Sweden to the knowledge of the authors. The municipalities cannot legally force a home owner to supply them with an EPC and there are no sanctions if the regulation is not fulfilled. The home owner is often reluctant to pay the fee for an EPC and instead waits until the house is put on sale on the market. In this study, 100 single-family houses were expected to have a valid EPC since 2 years passed after commissioning. However, the number of EPCs was 44 which means 44% compliance with the current regulation. This is problematic since the energy experts do not get the feedback needed to improve calculation procedures and input data. In larger construction projects, an energy coordinator is often appointed to follow up changes in the design and their influence on the energy use. For single-family houses this is rarely done. There is no formal certification or knowledge needed to submit an energy use calculation for a building permit application. However, there are guidelines and standardised input data available for energy use calculations. Even though the calculated energy use corresponds well with the energy use reported in the EPC, the calculation can be wrong, caused by erroneous allocation of the energy supply and energy demand, making comparisons unfeasible. Wrong data on e.g. efficiency of ventilation heat exchangers, thermal bridges and losses from circulating hot water circuits could rule out e.g. the influence by occupant’s behaviour. Analysis of a database containing the calculated energy use for 313 single-family houses built since 2009 in the municipality of Lerum revealed that there was no tendency for calculations targeting 4 Sweden - Differences between Measured and Calculated Energy Use in EPCs versus Building Permits the maximum allowed energy use. The most common heating system was an air to air heat pump followed by ground source heat pump. For 80 houses in the database, information on the heated floor area was available. This data showed that the energy use per square meter was lower for larger buildings. The floor area also influences the difference between the calculated and measured energy use which is higher in percentage for smaller buildings. The information on energy use, floor area, household electricity and hot water use in the calculation and EPC report were compared for six of the buildings in the database. The analysis showed that there are large deviations on which data is used and how it is obtained for the different buildings. For instance, non-compliant heated floor area was reported where the garage erroneously was included in the EPC report. For one of the houses, detailed numerical analysis were performed where 54 occupant scenarios were studied. The energy use varied between 39 kWh/m2 to 73 kWh/m2 compared to 26.6 kWh/m2 in the calculation report and 39 kWh/m2 in the EPC. This illustrates the importance of a methodology for correcting the energy use to normal use. The dispersion in energy use in buildings with different heating systems was analysed using a database of 1,753 EPCs for buildings in the metropolitan Gothenburg area. Both single-family houses and multi-family buildings were analysed. The energy use is influenced to a larger extent by the choice of heating system than by the choice of ventilation system. As discussed above, it is important to use the correct heated floor area and attribute the energy use to its correct demand and supply in the calculations. In many cases, the heated floor area was transformed from other sources than direct measurements in the building. The heated floor area was obtained by direct measurements in 63% of the multi-family buildings and in 100% of the single-family houses. The domestic hot water and facility electricity was allocated based on experience, and not measurements, for a majority of the buildings. The main conclusions of this study are that: - Energy use by occupant’s behaviour explain a large part of the difference between calculated and measured energy use. - Normal use is not standardised and therefore not accounted for in the EPC. - Few buildings have energy meters that separate energy use for heating from energy use which should not be included in the EPC, e.g. household electricity. - Bad compliance of the number of EPCs reported for new buildings 2 years after commissioning is caused by lack of follow-up actions. To improve the EPC scheme and quality of energy use calculation, further work is needed in the area of standardising input data, calculation procedures and reporting of EPC.
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27.
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28.
  • Johansson, Pär, 1986, et al. (författare)
  • Experiences from Interior Super Insulation of a Brick Wall from the 1800s
  • 2020
  • Ingår i: Current Topics and Trends on Durability of Building Materials and Components - Proceedings of the 15th International Conference on Durability of Building Materials and Components, DBMC 2020. - : CIMNE. - 9788412110180 ; , s. 497-504
  • Konferensbidrag (refereegranskat)abstract
    • Many brick buildings in Sweden today face a large need for renovation measures to prolong their service life and make other uses possible. Conventional thermal insulation materials, such as fibre glass and EPS, demand a thick layer of insulation to reach the energy targets. Super insulation materials, such as vacuum insulation panels (VIP) and aerogel blankets (AB), are thermal insulation components with a 3-10 times higher thermal resistance than conventional insulation materials. In this study, the effect of interior insulation using super insulation materials is investigated, using experiences from a case study in a brick wall from the 1800s. Earlier research has shown that interior insulation decreases the drying-out capacity of an exterior wall and increases the risk for freeze-thaw damages in brick walls. The case study building is an industrial building from 1896 with 470 mm homogeneous brick masonry walls insulated with both aerogel insulation and with vacuum insulation panels. Six heat flux sensors were installed in the wall and used to evaluate the thermal resistance of the wall with and without insulation. The initial measurements showed that the rate of water flow in the bricks is approximately three times higher than that in modern bricks. The average calculated U-value was reduced by 70% for the AB and 81% for the VIP layers, while measurements at the three occasions gave a reduction of 72-83% for the AB and 72-84% for the VIP layers, i.e. in the same order of magnitude.
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29.
  • Johansson, Pär, 1986, et al. (författare)
  • Field Testing of Interior Super Insulation Materials on a Brick Wall in an Industrial Building
  • 2019
  • Ingår i: Thermal Performance of the Exterior Envelopes of Whole Buildings. - 2166-8469. ; , s. 635-643
  • Konferensbidrag (refereegranskat)abstract
    • Conventional thermal insulation materials, such as fiber glass and EPS, demand a thick layer of insulation to reach the energy targets. Super insulation materials (SIM) are thermal insulation components with a 3-10 times higher thermal resistance than conventional insulation materials, such as vacuum insulation panels (VIP) and aerogel blankets (AB). They are efficient in increasing the thermal performance of walls when retrofitting, without significantly tampering with the wall thickness. Usually other measures such as changing windows or heating system are preferred before adding insulation to the walls, but to improve the thermal comfort and energy performance further, interior insulation is a possible alternative. In this study, an industrial building from 1896 with a 470 mm (1.5 ft) homogenous brick masonry wall is investigated regarding the hygrothermal performance and thermal inertia of the wall with interior insulation. Earlier research has shown that interior insulation decreases the drying-out capacity of the exterior wall and increases the risk for freeze-thaw damages in brick walls. In this study measurements from field investigations and simulations of a homogenous brick wall with 20 mm (0.8 in) interior VIP and 20 mm (0.8 in) aerogel blankets are compared to a non-insulated reference wall. The measurements showed that the wall was wet throughout the measurement period while the measured U-value was reduced with 82-83% for the AB and 81-84% for the VIP layers.
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30.
  • Johansson, Pär, 1986, et al. (författare)
  • Fältmätning på äldre tegelkonstruktion med invändig tilläggsisolering av superisoleringsmaterial
  • 2018
  • Ingår i: Bygg och teknik. - 0281-658X. ; 2018:5, s. 16-19
  • Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
    • Det är utmanande att finna passande renoveringsåtgärder för vårt äldre byggnadsbestånd som uppfyller dagens energikrav. En av åtgärderna som diskuteras är invändig tilläggsisolering av ytterväggen. Denna åtgärd innebär att ytterväggens temperatur sänks vilket kan ge en ökad risk för fuktproblem. I många byggnader finns det begränsningar i hur tjock väggen får vara och då kan superisoleringsmaterial vara intressant. I denna studie utgår vi från erfarenheter från våra tidigare studier där vi nu planerar att genomföra fullskaliga försök i fält. I artikeln presenterar vi försöksplanen tillsammans med de första resultaten.
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31.
  • Johansson, Pär, 1986, et al. (författare)
  • Interior insulation retrofit of a brick wall using super insulation materials: design of a field testing in an industrial brick building
  • 2018
  • Ingår i: Proceedings of the 7th International Building Physics Conference, IBPC2018, Syracuse, NY, USA, 23-26 September 2018. - 9781510890022 ; , s. 257-262
  • Konferensbidrag (refereegranskat)abstract
    • The societal demands on a more energy efficient building stock in Sweden creates challenges to find suitable retrofitting measures. One of the measures currently discussed is to use interior insulation. This measure leads to a reduced temperature in the wall, which increases to a risk for elevated moisture levels in the wall. When the thickness of the insulation layer is limited, super insulation materials (SIM) may be used. SIM can be divided into advanced porous materials, such as aerogel blankets (AB), and vacuum insulation panels (VIP). Often moisture from the outside is the major moisture source why a solution may be to apply a water repellent substance on the surface. A previous study showed that it is difficult to predict all the uncertainties in the field using the hygrothermal numerical simulations. This paper presents the design of a field investigation of a homogenous brick wall where AB and VIP are installed as interior insulation.
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32.
  • Johansson, Pär, 1986, et al. (författare)
  • Interior Insulation Retrofit of a Brick Wall Using Vacuum Insulation Panels: Re-Creation of Cultural Historical Values in Buildings from before 1945
  • 2016
  • Ingår i: Proceeding of the International RILEM Conference Materials, Systems and Structures in Civil Engineering 2016: Segment on Historical Masonry, August 22-24, 2016, Lyngby, Denmark.
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • The Swedish housing stock is once again in focus for national energy savings, as it was after the oil crises in the 1970s. The need for renovation is equally urgent in older stocks of housing, also in those that already have been renovated but are in need of further interventions. The first part of this project concerns inventorying of building components in buildings from before 1945 in need of a second major renovation. The focus of the inventorying is energy performance, moisture resistance, long-term durability and thermal comfort. The results from the inventories will be used to investigate alternative and improved solutions for re-renovation to recreate e.g. architectural details and cultural historical values. The possible thickness of the insulation layer is limited by the existing construction. Vacuum insulation panels (VIPs) require less thickness than conventional insulation materials to reach the same thermal resistance. Therefore, it could be more appropriate to use VIPs than conventional insulation materials when retrofitting the building envelope of listed buildings. In a previous study, a brick wall with wooden beams was insulated on the interior with vacuum insulation panels (VIPs) in a laboratory. It was shown that adding interior VIPs can reduce the energy use substantially in brick buildings. Adding interior insulation decreases the temperature during the cold season, which results in higher relative humidity. In the wooden beams, the moisture content increased more in the end of the beam than close to the interior surface of the brick. There was no significant difference between the RH in the wooden beam ends in the case with and without VIPs.
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33.
  • Johansson, Pär, 1986, et al. (författare)
  • Interior insulation using super insulation materials: saving energy and space
  • 2020
  • Ingår i: IOP Conference Series: Earth and Environmental Science. - : IOP Publishing. - 1755-1307 .- 1755-1315. ; 588:5
  • Konferensbidrag (refereegranskat)abstract
    • Interior insulation can be used in buildings where the exterior characteristics may not be altered due to cultural heritage protection. This is common for many buildings in Sweden from the period before 1941. Energy efficiency, thermal comfort and building performance are all affected by an interior insulation. Super insulation materials present novel opportunities to save both energy and space. The aim of this study is to investigate the benefits and drawbacks of using super insulation materials as interior insulation. A field study building was investigated for feasibility, which, together with interviews with professionals in the field of architecture, cultural heritage and building consultants, give a general overview. In conclusion, there are both benefits and drawbacks with interior insulation. Super insulation provides increased flexibility in terms of interior detailing and possibility to preserve characteristic elements. On building level interior super insulation could reduce the energy use by up to 20%. This gives energy savings of 0.5 TWh on national level and a reduction of 0.7% of the total CO2 emissions for heating the Swedish building stock. A drawback is that there are few examples and little experience from building with super insulation materials among both architects and other decision makers.
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34.
  • Johansson, Pär, 1986, et al. (författare)
  • Interior super insulation in heritage buildings: Challenges and possibilities to conserve heritage values and increase energy performance
  • 2020
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • Super insulation materials (SIM) are insulation material with a very low thermal conductivity, even lower than stagnant air. The aim of the project has been to show how these materials can be used to save energy and space, as well as to contribute to preservation of exterior character defining elements while maintaining the temperature and humidity performance of the walls when renovating buildings built before 1945. The project was performed by researchers in the fields of building physics and building conservation. Brick buildings in Sweden have been in focus, as these buildings have one of the largest energy efficiency potentials in the entire building stock. Brick buildings often challenge engineers and architects by having contradicting demands on energy efficiency and cultural heritage values. Often, the façades of these buildings have valuable character defining elements that make them difficult to insulate. There are also problems with the building components, technical service life and insufficient thermal comfort indoors. Experts in architecture and building conservation have contributed with knowledge through interviews and practical work at study visits and by reviewing drawings and construction documents. Collaboration partners, linked to the reference group, contributed to the project with their knowledge in interviews, meetings and seminars. The project has led to an increased knowledge and understanding of the technical difficulties that exist when preserving character defining elements while imposing energy efficiency measures with super insulation materials in buildings. Advantages of super insulation materials are, for example, that they add little thickness to the walls and that the flexible materials, such as aerogel blankets, can contribute to preservation of character defining elements in heritage buildings. The disadvantage of using super insulation materials as interior insulation is, as for all insulation materials, that the lowered temperatures in the wall can lead to increased moisture levels and also that the drying out capacity of the wall can decrease. Due to the risks with interior insulation of walls, it is important to thoroughly investigate if the wall is suitable for interior insulation.
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35.
  • Johansson, Pär, 1986, et al. (författare)
  • Recreation of cultural historical values in buildings from before 1945: Inventory with focus on building physics performance
  • 2017
  • Ingår i: Proceedings of the 14th International Conference on Durability of Building Materials and Components, Ghent University, Belgium, 29-31 May, 2017.
  • Konferensbidrag (refereegranskat)abstract
    • The housing stock in Sweden is getting more attention for national energy saving measures. This study is part of a larger multi-disciplinary research project in which building physicists, architects and building antiquarians work together to develop a holistic retrofitting approach. The first part of the project concerns inventories of building components in buildings from before 1945 in need of a second major renovation. The focus of the inventories is on energy performance, moisture resistance, long-term durability and thermal comfort. The inventories are used to investigate alternative and improved solutions for re-renovation to recreate e.g. architectural details and cultural historical values in balance with contemporary demands for function and aesthetics. In this study, different databases with information on energy use, year of construction, value year and geographical data were combined. It became evident that there is a large variation in quality of data and that different data sources have different information. For instance, among the investigated buildings, many were reported as being built in 1929. This was in most cases (71%) incorrect. We found that the year of renovation is often missing and the calculation of value year is not consistent or is lacking. Comparing the energy use for buildings with different year of construction may give the impression that older buildings have better energy performance. This is not correct. When looking into the value year, it becomes evident that the older buildings have been more renovated and there is no such correlation. The inventories also showed that it is usually the exterior wall facing the courtyard, or southern facing façades, which has additional insulation, and that great care has to be taken when changing façades and windows to balance cultural historical values.
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36.
  • Johansson, Pär, 1986, et al. (författare)
  • Renovation of buildings from before 1945: status assessment and energy efficiency measures
  • 2017
  • Ingår i: Energy Procedia. - : Elsevier BV. - 1876-6102. ; 132, s. 951-956
  • Konferensbidrag (refereegranskat)abstract
    • This paper presents inventories of building components and renovation measures in buildings from before 1945. External inventories with focus on durability, moisture performance and energy performance were made on 602 properties by building physicists, architects and building antiquarians. In addition to these, results from in-depth inventories were collected from 94 properties. The in-depth inventories also included cultural historical values and the interior status of buildings. The collected data showed that there is a lack of knowledge about the status of the building at the property owner. To suggest the most optimum energy efficiency and renovation strategy more information is needed.
  •  
37.
  • Johansson, Pär, 1986, et al. (författare)
  • Spread in energy use in buildings dependent on choice of heating and ventilation system
  • 2015
  • Ingår i: Proceedings of the 36th AIVC Conference, 23–24 September, 2015, Madrid, Spain. ; , s. 204-212
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • The energy use in buildings is dependent on the choices made during the design, construction and renovation. The causes for these differences are, among others, caused by the behavior of the occupant of the building and the choice of heating and ventilation system. The European scheme of Energy Performance Certificates (EPCs) aims at reducing the energy use in the built environment. It is most common to calculate (i.e. not measure) the energy use for the buildings which are affected by the scheme. In Sweden, on the other hand, the EPCs are normally based on measurements of the actual energy use in the building. This makes comparisons between calculated energy use for building permit and measured energy for EPCs possible. In this paper a study of the differences between the calculated and measured energy use and its correlation with the choice of heating and ventilation system is presented. This is done by detailed investigations of the calculated and measured energy use in 44 buildings. For further analysis, a database of 1 753 buildings with measured energy use (EPCs) is used to study the dispersion in energy use for buildings with different heating and ventilation systems. Analysis using numerical simulations tools on human behavior has also been performed. The results of the investigation can be used to further improve the measured EPCs.
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38.
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39.
  • Johansson, Pär, 1986, et al. (författare)
  • Using SIMs to re-create cultural historical values in buildings from before 1945
  • 2017
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • In Sweden, approximately 25% of the energy use in buildings is attributed to buildings from before 1945. In this study, in-depth inventories were made in 94 buildings of cultural historical values (ornamentation, original materials and paint, etc.) and the interior status of the building (cracks, moisture damage, additional insulation, etc.). The inventories were used to investigate alternative and improved solutions for re-renovation to re-create e.g. architectural details and cultural historical values using novel materials. Two case studies are investigated where super insulation materials can be an alternative during renovation.
  •  
40.
  • Larsson, Bengt, 1943-, et al. (författare)
  • The Effect and Cost Impact of Poor Airtightness : Information for Developers and Clients
  • 2007
  • Ingår i: Thermal Performance of the Exterior Envelopes of Whole Buildings. - Orlando : ASHRAE. - 2166-8469. - 9781933742281
  • Konferensbidrag (refereegranskat)abstract
    • Air movements in and through the building envelope affect the flows of not only heat, but also  moisture, gases and particles, in a building.  They often play a decisive part in determining moisture conditions, and thus  indoor environmental conditions in the building, and ultimately, the durability of the building structure.  Air flows affect thermal comfort and ventilation, and thus  air quality.  In addition, they also cause heat loss, both directly via ventilation, and through their effect on the performance of what are intended to be high-insulation structures.A previous joint project between SP Technical Research Institute of Sweden and Chalmers University of Technology investigated the importance of airtightness in the construction process. The project found that many types of damage and problems were caused by poor airtightness, that airtightness was seldom given the proper consideration that it deserved and that there was a major need for information on the effect of poor airtightness. One of the conclusions was that it is important to get developers/clients to treat airtightness more seriously.The objective of the follow-on project that is described here is therefore to make developers/clients (more) aware of the potential damage that can be caused by poor airtightness, together with  the “cost” of this damage/problem in a life-cycle perspective.  Hopefully, developers/clients will then specify and monitor airtightness requirements more clearly. The aim is therefore to develop tools and methods for informing developers/clients of the importance of good airtightness, and of the resulting extra costs that incur from paying insufficient attention to airtightness.The project has identified and assessed various consequences of poor airtightness, such as increased energy use, reduced thermal comfort, reduced air quality and moisture damages.The cost calculations show that the developer/client would benefit in most cases from an increased standard and follow up on airtightness. We have projected the work with three different levels of ambition: 0.2, 0.4 and 0.6 l/m2s (at 50 Pa pressure difference), and believe that the optimal airtightness lies somewhere in the region of these values, depending on the buildings use and equipment.
  •  
41.
  • Nilsson, Ingemar, et al. (författare)
  • Utvärdering av byggnaders täthet
  • 2009
  • Ingår i: Proceedings of Passivhus Norden 2009, Göteborg.
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)
  •  
42.
  • Olsson, Karl-Gunnar, 1955, et al. (författare)
  • Architecture and Engineering - education of Form and Force
  • 2019
  • Ingår i: IASS Symposium 2019 - 60th Anniversary Symposium of the International Association for Shell and Spatial Structures; Structural Membranes 2019 - 9th International Conference on Textile Composites and Inflatable Structures, FORM and FORCE. - 9788412110104 ; , s. 145-152
  • Konferensbidrag (refereegranskat)abstract
    • Inspired by the work and attitudes of architects and engineers like Jorg Schlaich, Renzo Piano, Piero Luigi Nervi, Sverre Fehn, Ted Happold, and environments like ILEK in Stuttgart and ETH in Zurich, a vision of a new kind of architects and engineers arose at Chalmers University of Technology in the early 2000. With support from the university and the branch, a double degree Architecture and Engineering programme was developed. Since the programme started in 2006 it has been a very popular programme, and among all Swedish MSc in Engineering and Master of Architecture programmes it has almost every year been the most difficult programme to get admitted to. The concept of the programme is a 180 ects (European Credit Transfer and Accumulation System) bachelor's degree, where the fundamentals from the engineering science: mathematics, mechanics, physics and materials, is combined with history of architecture and engineering, artistic explorative courses, and the fundamentals of the architectural design process. After three years the students can choose to continue for a Master of Science in Engineering with different possible directions, from mathematics and data science to industrial ecology, acoustics, management, structural engineering, and building technology, or to continue for a Master of Architecture. For the latter they need 150 etcs minimum in pure architectural design projects. In this paper the basic concepts of the programme, the culture developed around it and the strengths we can experience in the examined students will be discussed and reflected. Today students from the programme can be found at architecture and engineering companies all over the world and are appreciated for their ability to address complex architectural and engineering design issues with attitudes, insights and skills from the both professions.
  •  
43.
  • Psomas, Theofanis, 1983, et al. (författare)
  • Indoor humidity of dwellings and association with building characteristics, behaviors and health in a northern climate
  • 2021
  • Ingår i: Building and Environment. - : Elsevier BV. - 0360-1323 .- 1873-684X. ; 198
  • Tidskriftsartikel (refereegranskat)abstract
    • Data from a nationwide survey on the status of the Swedish residential building stock and indoor air quality was placed in the public domain by the National Board of Housing, Building and Planning of Sweden. The current research investigates the indoor humidity conditions in Swedish residential buildings, single-family houses and apartments, assessing the measurements from the extensive BETSI-survey against adjusted relative humidity levels based on existing norms and Standards. The aim of this study is to investigate associations and correlations between relative humidity levels and multiple building and system characteristics, occupancy patterns and behaviors and health symptoms-complaints. The analysis uses 13 categorical and 9 continuous variables-parameters of the examined dwellings. Analysis shows that low indoor relative humidity is a realistic issue in Swedish dwellings during the heating season. The issue is more prevalent in apartments than single-family houses. In addition, low indoor relative humidity seems to be more extensive in dwellings with higher indoor temperature, smaller volume, higher ventilation rate and frequent airing practices, lower number of occupants, constructed mainly after 1985, in city suburbs and in the northern parts of the country. The developed multinomial logistic regression model may predict very accurately the relative humidity level of the Swedish dwellings, during heating season. This analysis offers additional evidence to the scientific literature for possible correlation of low relative humidity with specific health symptoms, complaints and disturbances.
  •  
44.
  • Psomas, Theofanis, 1983, et al. (författare)
  • Low Relative Humidity, a Problem or Not in Swedish Dwellings?
  • 2021
  • Ingår i: INDOOR ENVIRONMENTAL QUALITY PERFORMANCE APPROACHES (IAQ 2020), PT 1. - 9781955516013
  • Konferensbidrag (refereegranskat)abstract
    • The current research investigates the relative humidity conditions in Swedish dwellings (678 apartments and single-family houses), comparing measurements from the 2007/2008 BETSI-survey (heating season), with the recommendations of the EN 16798:2019. Analysis shows that 61.4% of the apartments and 29.8% of the single-family houses belong to Cats. 3 and 4, which correspond to moderate and low level of expectation, respectively (mainly due to low relative humidity). The problem is bigger for dwellings with smaller volume, higher ventilation rate and indoor temperature, constructed mainly after 1985.
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