Latent Heat Flow in Light Weight Roofs and its Influence on the Thermal Performance

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    Abstract

    Under certain conditions, migration of small amounts of moisture in the envelope of buildings can cause heat flow through permeable thermal insulation materials due to the conversion of latent heat when moisture evaporates from a warm surface, diffuses through the insulation, and condenses on a colder surface. In these cases, themagnitude of the latent heat flux can be of the same order as the heat transfer by conduction. The latent heat transfer may result in a heat gain which coincides with other gains of an occupied building, and thus can cause an extra requirement for cooling. The paper reviews and quantifies the importance of heat flow processes in moist insulation systems. It then employs modeling to analyze the effect of extra heat gain caused bylatent heat transfer in the envelope on the thermal load on an office building chosen asan example. An extra cooling requirement of 6-7 % is found.
    Original languageEnglish
    JournalA S H R A E Transactions
    Volume104
    Issue number2
    Pages (from-to)930-940
    ISSN0001-2505
    Publication statusPublished - 1998
    Event1998 ASHRAE Annual Meeting, American Society of Heating, Refrigerating and Air-Conditioning Engineers - Toronto, Ontario, Canada
    Duration: 1 Jan 1998 → …

    Conference

    Conference1998 ASHRAE Annual Meeting, American Society of Heating, Refrigerating and Air-Conditioning Engineers
    CityToronto, Ontario, Canada
    Period01/01/1998 → …

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