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Effective penetration depth and effective resistance in moisture transfer

Cunningham, M. J.
1992
Building and Environment 27(3): 379-386

Cunningham, M. J., (1992), "Effective penetration depth and effective resistance in moisture transfer", Building and Environment 27(3): 379-386.
Abstract:
he concepts of "effective penetration depth" and "effective resistance" have appeared in the literature recently with reference to lumped models of moisture transfer. These quantities are shown to be equivalent. The effective depth for the one-sided case is shown to be ¡ÌD/2¦Ø and for the two-sided case is Image the material thickness, with corresponding effective resistances. Significantly, the effective penetration depth is shown to be not dependent upon the surface resistance of the boundary layer and any coatings. A simple lumped model used in defining the concepts gives very close agreement with the exact solution to the diffusion equation for the amplitude and phase of the mean moisture content for a periodic driving potential. This suggests that effective penetration depth and effective resistance can be regarded as universal physical quantities and not merely approximations or artifacts arising out of simplifications.

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Author Information and Other Publications Notes
Cunningham, M. J.
BPANZ, Moonshine Road, Judgeford, Private Rag 50908, Porirua, New Zealand. Department of Building Physics at Chalmers University of Technology, G6teborg, Sweden
  1. A field study of the moisture performance of roofs of occupied newly constructed timber framed houses
  2. A prarmeteric study of wall moisture contents using a revised variable indoor relative humidity version of the "MOIST" transient heat and moisture transfer model
  3. Inferring ventilation and moisture release rates from field psychrometric data only using system identification techniques
  4. Modelling of Moisture Transfer in Structures-III. A Comparison between the Numerical Model SMAHT and Field Data
  5. Predicting psychrometric conditions in biocontaminant microenvironments with a microclimate heat and moisture transfer model - description and field comparison
  6. The building volume with hygroscopic materials--an analytical study of a classical building physics problem
  7. Using hygroscopic damping of relative humidity and vapour pressure fluctuations to measure room ventilation rates  


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