Combined heat and moisture flow-philosophy and review of a Canadian Research Program/Ecoulements de chaleur et d' humidite combines

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Pages283287; # of pages: 5
Subjectair moisture transfer; heat transfer; building materials; building products; porosity; Moisture performance; transfert de l'humidite de l'air; transfert de chaleur; materiau de construction; produit du batiment; porosite
AbstractThis report reviews the program of research in Canada over the past twelve years and the philosophy which has developed concurrently with it. Calculations of heat flow through building materials are based on the assumption that the materials involved are dry. However, moisture is almost always present in practice. The presence of water in porous materials under conditions of heat flow creates a complication which scientists and engineers have not yet been able to deal with in any rational way. Experiments to date indicate that, for combined temperature and vapour pressure gradients, moisture flow occurs by means of a series-parallel arrangement of vapour-filled and liquid- filled pores, with continuous evaporation and condensation occurring between liquid and vapour boundaries. A rigorous analytical study would require complete and exact knowledge of the geometry of the pore system. This is clearly impossible in practice; the best we can do is describe the pore system in terms of a number of its overall characteristics, and this could greatly limit the potential for precise solutions.
Publication date
AffiliationNRC Institute for Research in Construction; National Research Council Canada
Peer reviewedNo
NRC number5329
NPARC number20374071
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Record identifiercaa178f0-8271-4d63-9f33-a55502973d6f
Record created2012-07-23
Record modified2016-05-09
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