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Related Concept
  • HAM: computer models
  • used: fungi: growth and growth model
  • computer codes for heat-air-moisture transfer



    • Related References
  • Hens, H. and Janssens, A., (1993), Inquiry on HAMCAT codes
  • Karagiozis, A., (2002), Building enclosure hygrothermal performance study phase I
  • Karagiozis, A., Kuenzel, H., Holm, A. and Desjarlais, A., (1999), An educational hygrothermal model: WUFI-ORNL/IBP
  • Salonvaara, M. Karagiozis, A., and Holm, A., (2001), Stochastic building envelope modeling -- the influence of material properties
  • Straube, J.F. and Burnett, E.F.P, (2001), Overview of hygrothermal (HAM) analysis methods




    		• Essay:

    HAM: WUFI-ORNL/IBP

    New Tool to Model Building Temperatures and Moisture Contents--New software may provide designers and researchers with a simple, accurate tool to evaluate the temperature and moisture conditions within any building enclosure over time. Thus, designers will be able to model different climatic conditions, materials, and assemblies to see how wind-driven rain might penetrate the envelope, how much condensation will form under what conditions, and where and when wood decay is likely to occur.

    The new software, WUFI-ORNL/IBP, was released by Oak Ridge National Laboratory (ORNL) and Germany's Fraunhofer Institute of Building Physics (IBP). It was developed by customizing the original European version of WUFI software for North America. Introduced in 1994, the European version has been accepted as a reliable research and design tool. Currently, more then 200 universities and research institutes, plus a growing number of private firms, use that version. John Straube of the University of Waterloo, Ontario, Canada, who has worked with WUFI for more than 5 years, says the software can accurately demonstrate the influence of wind-driven rain, solar radiation, and night sky radiation on the hygrothermal performance of wall systems. "I think WUFI-ORNL/IBP could well put an end to some of the controversies that have persisted in the building design community, such as when and where vapor retarders should be used." Straube notes that the software should also be of help in determining how the moisture contained in wet-blown cellulose, fresh concrete, and other materials could affect the performance or durability of surrounding materials.

    The North American version (WUFI-ORNL/IBP) will soon be available free of charge via the ORNL website (www.ornl.gov/btc/moisture) to anyone living in the United States or Canada. The current model has a somewhat limited database of material properties, but more materials will be added in the months ahead. This model will also be included in Moisture Analysis for Buildings, a manual to be published by the American Society for Testing and Materials.

    For more information on WUFI-ORNL/IBP, contact Achilles Karagiozis at 865-576-3924 or karagiozisan@ornl.gov.

    [Source: Energy Design Update, October 2000]

    Salonvaara, M. Karagiozis, A., and Holm, A., 2001, Stochastic building envelope modeling¡ª the influence of material properties The model uses a predefined format for material property descriptions. Other simplifications or limitations include the following: hysteresis of the moisture retention curve is not taken into account, air flow by total pressure difference is not included, and the influence of ice formation on enthalpy and liquid transport is accounted for but not its effect on thermal conductivity.


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