Influences of the indoor environment on heat, air and moisture conditions in building components: Boundary conditions modeling

Current models to predict heat, air and moisture (HAM) conditions in building components assume uniform boundary conditions, both for the temperature and relative humidity of the air in an indoor space as well as for the surface transfer coefficients. Such models cannot accurately predict the HAM conditions in the component with non-uniform air temperature or relative humidity distributions in an indoor space. Moreover, the heat and moisture surface transfer coefficients strongly depend on the local air velocity, local temperature, water-material interactions and water content at the material surface and surface texture of the material. A more detailed description and prediction of the interaction between the indoor environment and the HAM conditions in the building component would be desired. The predicted heat, air and moisture conditions in the building component, as well as on its surfaces, will serve as input for subsequent assessment of the durability of building components. In the work presented in this paper, an airflow model is used to describe the non-uniform indoor airflow near the building component. The airflow model is integrated into an existing HAM building component model. Approaches to model the non-uniform indoor airflow near the building component have been investigated. A sensitivity study has been carried out to investigate the possible benefits of integrating the non-uniform indoor airflow near the building component in the HAM component model for a building component with specific characteristics. Advantages, disadvantages and limitations of the developed models are evaluated.