The water-permeability, moisture-diffusivity, and sorptivity concepts of modeling liquid water transport in porous building materials are analyzed. An overall assessment of the particular models is performed using the moisture profiles measured for two types of autoclaved aerated concrete. The water-permeability and moisture-diffusivity modeling approaches are found suitable from a point of view of accuracy of moisture-transport simulation but they have certain limitations. While the water-permeability concept is advisable for compact materials, the moisture-diffusivity concept should be preferred for materials with a high water penetration rate. Therefore, a combination of both these approaches in a single laboratory is beneficial. The sorptivity concept, on the other hand, can be recommended for a basic assessment of water transport capabilities of building materials only.

The radiative heat transfer coefficient at high temperatures is determined using a combination of experimental measurement and computational modeling. In the experimental part, cement mortar specimen is heated in a laboratory furnace to 600°C and the temperature field inside is recorded using built-in K-type thermocouples connected to a data logger. The measured temperatures are then used as input parameters in the three dimensional computational modeling whose objective is to find the best correlation between the measured and calculated data via four free parameters, namely the thermal conductivity of the specimen, effective thermal conductivity of thermal insulation, and heat transfer coefficients at normal and high temperatures. The optimization procedure which is performed using the genetic algorithms provides the value of the high-temperature radiative heat transfer coefficient of 3.64 W/(m 2 K).

Thermal and hygric properties of porous materials depend on the content of moisture present in their pore system. As they appear as input parameters of computational models of heat and moisture transport, neglecting this dependence can affect the results of computational simulation of both hygrothermal performance and energy balance. In this paper, several multi-layered systems of building materials are analyzed. The hygric and thermal properties of materials forming the particular systems are determined at first. Then, the effect of their dependence on moisture content on the moisture and temperature fields is analyzed using a computational model. The consequences of neglecting the dependence of the particular parameters on moisture content are discussed and recommendations for the energy-related assessments of the studied multi-layered systems are formulated.

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The suitability of a water vapor transport parameter determined by the cup method for the description of water vapor transport in porous building material is analyzed in the paper. The relative humidity profiles are measured by a transient method with different water vapor pressure gradients. Moisture profiles calculated using a mathematical model are compared with the measured profiles. The goodness-of-fit tests are calculated for different experimental setups. The possibility of application of the analyzed water vapor transport parameter is discussed.