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Conservative modelling of the moisture and heat transfer in building components under atmospheric excitation

Janssen, H., Blocken, B. and Carmeliet, J.
2007
International Journal of Heat and Mass Transfer, 50(5-6): 1128-1140
Hygrothermal modelling; Numerical simulation; Heat and moisture transfer; Porous materials; Atmospheric boundary conditions; Conservative modelling

Janssen, H., Blocken, B. and Carmeliet, J., (2007), "Conservative modelling of the moisture and heat transfer in building components under atmospheric excitation", International Journal of Heat and Mass Transfer, 50(5-6): 1128-1140.
Abstract:
While the transfer equations for moisture and heat in building components are currently undergoing standardisation, atmospheric boundary conditions, conservative modelling and numerical efficiency are not addressed. In a first part, this paper adds a comprehensive description of those boundary conditions, emphasising wind-driven rain and vapour exchange, the main moisture supply and removal mechanism, respectively. In the second part the numerical implementation is tackled, with specific attention to the monotony of the spatial discretisation, and to the mass and energy conservation of the temporal discretisation. Both issues are illustrated with exemplary hygrothermal simulations. Numerical efficiency is treated in two follow-up papers.

Quoted for "Because of the non-linear nature of the transport equations, mass and energy conservation is not guaranteed: e.g. the slope of isotherm curve isnot constant during a time step. To solve this problem Janssen et al. proposed an iterative solution procedure in which the property that has to be conserved is

estimated by a truncated Taylor series"

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Related Concepts

Author Information and Other Publications Notes
Janssen, H.
  1. A comparison of the Nordtest and Japanese test methods for the moisture buffering performance of building materials
  2. Impact, absorption and evaporation of raindrops on building facades
  3. In situ determination of the moisture buffer potential of room enclosures
  4. Qualitative and quantitative assessment of interior moisture buffering by enclosures
  5. The influence of soil moisture in the unsaturated zone on the heat loss from buildings via the ground
  6. The influence of soil moisture transfer on building heat loss via the ground
  7. Wind-driven rain as a boundary condition for HAM simulations: Analysis of simplified modelling approaches  
Blocken, B.
Laboratory of Building Physics, Department of Civil Engineering, Katholieke Universiteit, Leuven, Belgium. http://perswww.kuleuven.ac.be/~u0008129/
  1. A review of wind-driven rain research in building science
  2. A simplified numerical model for rainwater runoff on building facades: Possibilities and limitations
  3. Driving rain on building envelopes II: representative experimental data for driving rain estimation
  4. Pedestrian wind environment around buildings: literature review and practical examples
  5. Quantification of driving rain as a boundary condition for water flow modelling in building parts
  6. Rainwater runoff from building facades: A review
  7. Spatial and temporal distribution of driving rain on a low-rise building
  8. Spatial and temporal distribution of driving rain on buildings: numerical simulation and experimental verification
  9. Validation of external BES-CFD coupling by inter-model comparison
  10. Wind, rain and the building envelope: studies at the Laboratory of Building Physics, KULeuven
  11. Wind-driven rain as a boundary condition for HAM simulations: Analysis of simplified modelling approaches  
Carmeliet, J.
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 multiscale network model for simulating moisture transfer properties of porous media
  3. A review of wind-driven rain research in building science
  4. A simplified numerical model for rainwater runoff on building facades: Possibilities and limitations
  5. Description of the moisture capacity of building materials
  6. Determination of the isothermal moisture transport properties of porous building materials
  7. Determination of the liquid water diffusivity from transient moisture transfer experiments
  8. Determination of the moisture capacity of porous building materials
  9. Driving rain on building envelopes II: representative experimental data for driving rain estimation
  10. Microscopic analysis of imbibition processes in oolitic limestone
  11. Modeling fluid flow in fractured media using continuum, network and discrete aproaches
  12. Pedestrian wind environment around buildings: literature review and practical examples
  13. Performance prediction for masonry walls with EIFS using calculation procedures and laboratory testing
  14. Position paper on material characterization and HAM model benchmarking
  15. Rainwater runoff from building facades: A review
  16. Simulating non-isothermal water vapour transfer: an experimental validation on multi-layered building components
  17. Spatial and temporal distribution of driving rain on a low-rise building
  18. The influence of soil moisture in the unsaturated zone on the heat loss from buildings via the ground
  19. Wind, rain and the building envelope: studies at the Laboratory of Building Physics, KULeuven
  20. Wind-driven rain as a boundary condition for HAM simulations: Analysis of simplified modelling approaches  


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