Ralf Klein

Numerical and experimental investigation of the hygrothermal response of timber frame walls with an exterior air barrier

Laboratory tests and numerical simulations to study the hygrothermal consequences of using an exterior air barrier in light-weight building envelopes are discussed. Full-scale test walls are placed between a vertical hot and coldbox, operating at controlled temperatures, humidity levels and total air pressures. The test walls are exposed to different boundary conditions during five consecutive measuring stages. Each test wall is provided with 18 thermocouples, 15 relative humidity, 3 heat flux and 1 pressure gauge sensor, covering the most important positions of the wall. In this way, the obtained results can be used as detailed validation data for heat, air and moisture (HAM)-models with a strong focus on natural and forced air convection. The main emphasis of this article is the evaluation of a numerical model with the current dataset. The model used is a modified version of DELPHIN 5 including a quasi-steady state airflow model with the ability to capture natural convection.