Temperature gradient effects on moisture transport in porous building materials

P.H. Baker, G.H. Galbraith, R.C. McLean

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

Whilst considerable research has been carried out on the process of moisture transmission through porous building materials under a concentration gradient with isothermal conditions, limited experimental data are available on the influence of temperature gradients on moisture transfer rates. Such thermodiffusion can be predicted from irreversible thermodynamics, however, its significance to concentration-driven transfer in materials has not been definitively established. Models for the prediction of moisture movement in building structures generally neglect such effects, and rely on moisture transport properties based on isothermal measurements. This paper describes an investigation to determine the significance of non-isothermal effects on the total moisture transfer through building materials. The investigation concluded that the vapour pressure gradient is the critical driving potential for moisture transfer, whilst thermodiffusion is not significant. Practical application: Building professionals can be confident that the use of vapour permeabilities of building materials measured under isothermal conditions are satisfactory for the prediction of moisture transport through building envelopes under temperature gradients: no correction for thermodiffusion effects is necessary.
LanguageEnglish
Pages37-48
Number of pages11
JournalBuilding Services Engineering Research and Technology
Volume30
Issue number1
DOIs
Publication statusPublished - 2009

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Thermal gradients
Porous materials
Moisture
Pressure gradient
Vapor pressure
Transport properties
Vapors
Thermodynamics

Keywords

  • moisture transport
  • porous building materials
  • isothermal conditions

Cite this

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Temperature gradient effects on moisture transport in porous building materials. / Baker, P.H.; Galbraith, G.H.; McLean, R.C.

In: Building Services Engineering Research and Technology , Vol. 30, No. 1, 2009, p. 37-48.

Research output: Contribution to journalArticle

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