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A quasi-steady state implementation of air convection in a transient heat and moisture building component model

Langmans, J., Nicolai, J. L. a., Klein, R. and Roels, S.
2012
Building and Environment, Volume 58, December 2012, Pages 208-218


Langmans, J., Nicolai, J. L. a., Klein, R. and Roels, S., (2012), "A quasi-steady state implementation of air convection in a transient heat and moisture building component model", Building and Environment, Volume 58, December 2012, Pages 208-218.
Abstract:
For many years, the coupled heat, air, and moisture (HAM) transport through multilayered building components has been an important research topic. As a result, a great number of numerical simulation tools have been developed to asses and predict the hygrothermal behaviour of building enclosures. But, while the literature shows that air transport has a significant impact on the heat and moisture response of light weight constructions, only few existing heat and moisture transport models include air flow as an active mass component. One of the reasons is the different time scale of air transport compared to the other transported quantities and the resulting difficulties in achieving acceptable simulation performance.

The current article presents a quasi-steady state airflow model implementation in an existing transient HAM-model. The air transport is described as Darcy flow in porous media including a body force term to capture natural convection. One particular aim is the prediction of significant effects such as overlaying buoyant and externally driven air flow on the hygrothermal behaviour of building envelope components with sound simulation performances. Furthermore, the article includes an evaluation of the model for which three validation cases from the literature are used to show the applicability and limitations of the presented approach.


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Author Information and Other Publications Notes
Langmans, J.
     
Nicolai, J. L. a.
     
Klein, R.
     
Roels, S.
Department of Civil Engineering Laboratory of Building Physics Catholic University of Leuven, Belgium
  1. A comparison of different techniques to quantify moisture content profiles in porous building materials
  2. A comparison of the Nordtest and Japanese test methods for the moisture buffering performance of building materials
  3. Description of the moisture capacity of building materials
  4. Determination of the isothermal moisture transport properties of porous building materials
  5. Determination of the liquid water diffusivity from transient moisture transfer experiments
  6. Determination of the moisture capacity of porous building materials
  7. Impact, absorption and evaporation of raindrops on building facades
  8. In situ determination of the moisture buffer potential of room enclosures
  9. Microscopic analysis of imbibition processes in oolitic limestone
  10. Modeling fluid flow in fractured media using continuum, network and discrete aproaches
  11. Position paper on material characterization and HAM model benchmarking
  12. Qualitative and quantitative assessment of interior moisture buffering by enclosures
  13. Review of mould prediction models and their influence on mould risk evaluation
  14. Simulating non-isothermal water vapour transfer: an experimental validation on multi-layered building components
  15. Wind-driven rain as a boundary condition for HAM simulations: Analysis of simplified modelling approaches  



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