Benchmark experiments for moisture transfer modelling in air and porous materials

Abstract

Abstract.The presence of hygroscopic materials has a large impact on the moisture balance of buildings. Nowadays, HAM (Heat, Air and Moisture) models are widely used to investigate the role of hygroscopic materials on the performance of buildings, i.e. on the building envelope, the indoor climate and valuable objects stored within the building. Recently, these HAM models are being coupled to CFD models to study the moisture exchange between air and porous materials on a local scale (microclimates), or to BES (Building Energy Simulation) models which focus on the interaction between air and porous materials at building level. Validation of these numerical codes is essential to gain confidence in the codes. However, available experimental data are rather scarce. This paper describes the design of a new test facility for humidity experiments. A dedicated AHU system is used to provide well-controlled air (constant temperature and RH) to an airtight and well-insulated room-size test chamber. In one of the walls of the chamber a calcium silicate sample is installed. A step in RH of the supply air is imposed. Temperature and RH of the supply air, the room air and on various depths inside the sample are continuously registered during the experiments. Two types of experiments were carried out to validate a coupled CFD-HAM model and a coupled BES-HAM model. The temperature outside the test chamber was controlled and there was no temperature difference imposed across the chamber walls. Comparing the models with the measured data gave satisfactory agreement.

Validation of a coupled heat, vapour and liquid moisture transport model for porous materials implemented in CFD

“…By implementing a detailed HAM model into an existing CFD solver (Fluent®) he was able to model the heat and moisture transport in the air and porous material simultaneously. The coupled model was validated using climate chamber experiments [12]. However, Steeman only modelled vapour diffusion as a transport mechanism in the porous material.…”

Effect of Carbonization Temperature on Hygric Performance of Carbonized Fiberboards

“…Due to the storage capacity of the building envelope and furniture, moisture was absorbed by porous surfaces before reaching the other rooms. (Van Belleghem et al 2011;). …”

Heat Transfer Through Vertically Downward-Blowing Single-Jet Air Curtains for Cold Rooms

“…The measurement results from this case were used to validate a CFD (computational fluid dynamics) model of a vertical downward blowing air curtain. Past studies [4][5][6][7] showed that CFD can be a useful tool for heat transfer assessment in buildings and building applications. This CFD model was then used to perform a parameter study from which the correlation between various parameters (outlet velocity, nozzle width, door geometry) and the heat transfer can be determined.…”