Hygrothermal conditions in exterior walls for passive houses in cold climate considering future climate scenario

Björn Berggren, Maria Wall

Research output: Contribution to conferencePaper, not in proceedingpeer-review

Abstract

Reduction of energy use constitutes as an important measure for climate change mitigation. Buildings today account for 40% of the world’s primary energy use and 24% of the greenhouse gas emissions [International Energy Agency (IEA) 2011]0. The concept of passive houses is one of many necessary measures for climate change mitigation. To reach the passive house ambition in cold climates, increased thermal resistance of the building envelope is vital. Increasing the thermal resistance in combination with climate change will result in a different microclimate within the building envelope.
Possible future micro climate in exterior walls are produced by hygrothermal simulations using the numerical software WUFI . The simulations are conducted for four different locations in Sweden, where the main difference is geographically in the respect of latitude, for the year period 1985-2098. Regional climate is based on data from the Swedish Meteorological and Hydrological Institute, using regional climate models developed at the Rossby Centre, RCA3. The RCA3 model covers Europe with a horizontal resolution of 50x50 kilometres. The boundary conditions are from the global climate model ECHAM5.
The increased risk for performance failure due to high humidity levels is conducted by assessing the result from the simulations combining three different evaluation models described in, which mainly differ in respect of the consideration of fluctuating hygrothermal conditions.
The investigations show that the risk of mould growth will increase in the future. However, adding more insulation to the exterior side of a wood frame construction results into more stabile hygrothermal conditions. Based on the results from the simulations it is recommended that all constructions with bio gradable materials should be given exterior insulation to decrease the risk of mould growth. Furthermore, building elements must always be designed to have the ability to dehydrate moisture that has entered, whether it is due to driving rain, built in moisture or other reasons.
Original languageEnglish
Publication statusPublished - 2012
Event5th Nordic Passive House Conference - Trondheim
Duration: 0001 Jan 2 → …

Conference

Conference5th Nordic Passive House Conference
Period0001/01/02 → …

Subject classification (UKÄ)

  • Building Technologies

Free keywords

  • Passive house
  • hygrothermal
  • mold
  • climate scenario
  • climate change

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