Predicting indoor temperature and humidity conditions including hygrothermal interactions with the building envelope

The hygrothermal behaviour of the building envelope affects the overall performance of a building. There are numerous tools for the simulation of the heat and moisture transfer in the building enve-lope and also whole building simulation tools for energy calculations. However, working combinations of both models for practical application are just about to be developed. In this paper such a combined model, that takes into account moisture sources and sinks inside a room, input from the envelope due to capillary action, diffusion and vapour ab- and desorption as a response to the exterior and interior climate conditions as well as the well-known thermal parameters will be explained. By way of well documented field experiments the new model is validated and the moisture buffering capacity of the building envelope is determined. In the conclusions the possible range of future applications of hygrothermal building performance models is addressed and demands for further research are indicated.