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Uncertainty of hygrothermal calculations

Holm, A.H. and H.M. Kščnzel
2002
6th Symposium on Building Physics in the Nordic Countries (Trondheim, Norway, 6/17/2002), pp. 611-618, July 01

Holm, A.H. and H.M. Kščnzel, (2002), "Uncertainty of hygrothermal calculations", 6th Symposium on Building Physics in the Nordic Countries (Trondheim, Norway, 6/17/2002), pp. 611-618, July 01.
Abstract:
INTRODUCTION

The hygrothermal behaviour of a building component that is exposed to weather or soil humidity is an important aspect of its overall performance. Its importance is increasing as modern dwellings become more airtight and show elevated indoor humidity levels. Assessing the hygrothermal performance is, therefore an essential step in designing new buildings or planning rehabilitation measures. Until now, the planner could only rely on manual design tools, such as the Glaser method described in German standard DIN 4108. Because of inherent simplifications and limitations, this simple steady-state assessment method only allows to estimate the risk of interstitial condensation under standard conditions. The moisture situation in a building component must be simulated and assessed realistically. This means, hygric phenomena must be accounted for in a more comprehensive way. This includes the effects of essential influences such as driving rain, rising dampness, construction moisture, hygroscopic moisture and reverse diffusion. Therefore numerous models and computer programs for calculating transient hygrothermal processes have been developed in different countries. Some have shown the ability to produce useful results.

The recent hygrothermal models have been validated by extensive and well-documented laboratory and outdoor experiments. In most cases, a good agreement between measurement and calculation can be observed. Only occasionally the real behaviour does deviate significantly from the calculated results. Reasons may be that the calculation is not accurate enough or that the hygrothermal model does not include all of the relevant physical processes. When the accuracy of hygrothermal models is to be assessed, possible restrictions and limitations must be determined and investigated in advance.

Categorize the parameters that have uncertainty, 3 methods for uncertainty analysis,
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  • This link has not been checked.ANSI-- American National Standards Institute
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  • This link has not been checked.DOE--Department of Energy
    "The Department of Energy's overarching mission is enhancing national security. Responsibility for accomplishing this mission is shared between four principal program lines."
  • This link has not been checked.Laboratory of Building Physics, Leuven, Belgium
    "...research and educational activities in the field of heat and mass transfer in building materials, building parts and buildings, the energy use in buildings, building installations and building acoustics. Also research in urban physics is part of our activities.
  • Conference: Building Physics : Conference
  • Conference: Building Physics Symposium in the Nordic Countries

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Author Information and Other Publications Notes
Holm, A. H.
     
Kščnzel, H. M.
Fraunhofer-Institute for building physics (Director: Prof. Dr.-Ing. habil. Dr. h.c. mult. Dr. E.h. mult. K. Gertis)
  1. Calculation of heat and moisture transfer in exposed building components
  2. Combined effect of temperature and humidity of the detoriation process of insulation materials in ETICS
  3. Flexible vapor control solves moisture problems of building assemblies - smart retarder to replace the conventional PE-film
  4. Moisture buffering effects of interior linings made from wood or wood based products
  5. Mold growth prediction by computational simulation
  6. Simulation of indoor temperature and humidity conditions including hygrothermal interactions with the building envelope
  7. Simultaneous heat and moisture transport in building components. one- and two-dimensional calculation using simple parameters
  8. Two-dimensional transient heat and moisture simulations of rising damp with WUFI 2D
  9. WUFI-ORNL/IBP - A North American Hygrothermal Mode  


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