Morelli, Martin

Udvikling af metode til helhedsorienteret energirenoveringI det seneste årti har Den Europæiske Union arbejdet intenst på at øge energieffektiviteten i byggesektoren med henblik på en frigørelse fra brugen af fossile brændsler. Fokus er i årenes løb blevet flyttet fra nye energieffektive bygninger over mod eksisterende bygninger. Dette medfører, at energirenovering sandsynligvis vil blive intensiveret i de kommende år.En metode til helhedsorienteret energirenovering blev udviklet. Metoden inkluderede gennemførelsen af renovering på bygningsniveau så vel som projektering af energibesparende foranstaltninger. Fokus var på etageboliger bygget i perioden 1850-1930 med indlejrede træbjælker i fuldmurede ydervægge. Resultaterne viste en betydelig reduktion i energiforbruget af disse bygninger. Reduktionen blev opnået ved at forbedre klimaskærmens termiske ydeevne samt installation af mekanisk ventilation med varmegenvinding. Renoveringens holdbarhed kan dog blive reduceret pga. råd i træbjælkerne eller skimmelsvamp bag den indvendige isolering.Det energibesparende potentiale i to etageboliger blev undersøgt ved parameteranalyser af eksisterende energibesparende foranstaltninger for både klimaskærmen og den mekaniske ventilation. Efterfølgende blev en metode til en komponent-baseret, økonomisk optimering udviklet, hvor evalueringskriteriet var energiprisen for vedvarende energi. Resultaterne fra begge analyser gav en besparelse på ca. 70% for det teoretiske energiforbrug. En økonomisk sammenligning blev udført mellem en ny bygning og den optimerede energirenovering. Resultaterne indikerede, at energirenovering var fordelagtig i forhold til en udskiftning af bygningen.Et indvendigt efterisoleret, massivt murværk med indlejrede træbjælker blev undersøgt ved brug af 2D hygrotermiske simuleringer og fuldskala forsøg. To energibesparende foranstaltninger blev designet; en med isolering påført hele væggen, og en hvor isoleringen stoppede 200 mm over træbjælken. Risikovurdering blev anvendt til at bestemme de kritiske dele af konstruktionen. Simuleringsresultaterne viste, at meget slagregn og høj indvendig relativ fugtighed i bygningen øger risikoen for både råd i bjælken og skimmelvækst bag isolering.Simuleringerne indikerede, at en lille slagregnspåvirkning ikke øger risikoen for nedbrydning af bjælken. Dette blev understøttet af målinger. Målinger af temperatur og relativ fugtighed viste, at betingelserne for skimmelvækst var til stede. Der blev imidlertid ikke dokumenteret skimmelvækst ved demontering af den indvendige isolering. Der blev udviklet en metode til projektering af energibesparende foranstaltninger baseret på både Failure Mode and Effect Analysis og Limit States Design. Denne metode blev kombineret med den tidligere udviklede metoden til økonomisk optimering af bygningsrenovering: Først blev den optimerede kombination af energibesparende foranstaltninger bestemt. Kombinationen af foranstaltninger blev evalueret i forhold til om den eksisterende bygningen skulle erstattes af en ny bygning. Derefter vurderedes udformningen af de energibesparende foranstaltninger i forhold til re-design, udfærdigelse af en vedligeholdelsesplan eller vurdering af holdbarheden.Development of a method for holistic energy renovationDuring the last decade, the European Union has worked intensively to improve the energy efficiency in the building sector, aiming at liberation from the use of fossil fuels. The focus has shifted from new energy efficient buildings towards existing buildings. This implies that energy renovation likely will be intensified in the coming years. A method for holistic energy renovation was developed that embraced the viability of the whole building renovation as well as the design of the energy saving measures. The focus was on multi-family buildings built in the period 1850-1930 with embedded wooden beams in solid masonry walls. The results indicated significant reduction of the energy usage of these buildings. This was obtained by improving the thermal performance of the building envelope and installing mechanical ventilation with heat recovery. The long-term performance of the renovation may be reduced due to mould growth behind the interior insulation or decay of the wooden beams. The energy saving potential in two multi-family buildings was investigated by parameter studies of existing energy saving measures for both the building envelope and mechanical ventilation. Subsequently, a method was developed for a componentbased economical optimisation using the energy price for renewable energy as constraint. The results from both investigations showed an approximately 70% reduction for the theoretical energy usage. An economical comparison was conduct ed between a new building and the optimised energy renovation. The results indicated that energy renovation was beneficial compared to replacing the building. An interior post-insulated, solid masonry wall with embedded wooden beams was investigated by two-dimensional hygrothermal simulations and full-scale measurements. Two energy saving measures were designed; one with insulation applied on the entire wall surface, and one leaving a 200 mm gap in the insulation towards the wooden beam. Risk assessment was conducted to determine the critical part of the structure. Simulation results showed that a large amount of wind driven rain and a high indoor relative humidity increases the risk for both mould growth behind the insulation and decay of the wooden beam. A small wind driven rain exposure indicated no risk regarding deterioration of the beam. This was supported by measurements. Measurements of temperature and relative humidity showed that conditions for mould growth were present. However, no signs of mould growth were documented at dismantling of the interior insulation. A method was developed for the design of energy saving measures based on both Failure Mode and Effect Analysis, and Limit States Design. This method was combined with the previously developed method for economical optimisation of building renovation: Firstly, the optimised combination of energy saving measures was determined. The combination of energy saving measures was evaluated against replacing the existing building with a new building. Secondly, the design of energy saving measures was assessed whether to re-design, formulate a maintenance plan or assess the durability

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Development of a method for holistic energy renovation

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Development of a method for holistic energy renovation

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