Prototype of an experimental stand for investigating heat and moisture transfer phenomena in building materials

The prototype of an experimental stand for studying drying building materials is presented in the paper. The stand is designed to validate a numerical model of heat and moisture transfer in porous media. The experiment was conducted in forced convection conditions. A building material sample was located in a holder so that only one surface (the top one) had contact with flowing air in the duct. The sample exchanged heat and moisture with the flowing air through this surface. Two fans at the end of the duct induced the airflow through the vent. The stand was placed in a climatic chamber, stabilizing the temperature (22.5°C) and relative humidity (50%) during the experiment. A tensometric beam was used to measure the temporal variation of the sample mass. A resistance thermometer (PT100) was used to measure the temperature on the sample surface. Four samples (90×90×30mm each) from cellular concrete were prepared. Each sample was dried before the experiment, immersed in water for 24h, then wrapped in the foil and preconditioned (24h) in a climate chamber to equalize the temperature. The samples were dried on the stand for 48 hours. The procedure was repeated twice. The repeatability of results has been achieved. However, the accuracy of the experimental stand was insufficient. Hence further modifications need to be made were proposed.