ABSTRACT
The heat transmission through a moist porous material consists of the following components:
the well-known moisture-dependent thermal conductivity λ(w)
the enthalpy flow coupled with vapour and water mass-flow
the latent enthalpy flow caused by phase changes
the air enthalpy flow in case of air movement through the material
In this paper the model of the coupled heat, air and moisture transport in building structures and the results of the numerical solution are presented. Under typical meteorological climate conditions (test reference year: hourly values of temperature, relative humidity, direct and diffuse short wave radiation, longwave radiation balance, wind velocity, wind direction and rain) the moisture behaviour and the total heat losses for multilayered envelope components are analyzed. Moreover, the influence of moisture content and moisture movement on the thermal conductivity measurement (by means of a hot-plate-apparatus and a needle probe) and on the thermal resistance measurement (active u-values method) is quantified.
