Validation of coupled airflow and heat transfer routines in a building simulation tool

Several organizations and expert groups have released different test cases for the validation of building simulation tools. This study is a summary of validation results obtained by a new whole building simulation tool developed at a Finnish national research organization. Currently, this new simulation tool is focused on heat transfer and airflow in buildings and their effect on indoor air quality and thermal comfort. In the future, the new simulation tool can be expanded to analyze the energy consumption of buildings because the model solves the coupled mass, momentum, and energy balance equations. Ventilation fans, wind, and thermal buoyancy are included as driving forces for the air infiltration and ventilation processes. Multimode heat transfer- including convection, conduction, and radiation -is modeled to ensure the reliability of thermal simulation results. When validating the routines in a numerical model, it is important to apply both simple and complex tests. It is proposed that a series of analytical, intermodel, and empirical tests are needed to verify different aspects of a numerical model. As a result, several validation tests from the literature are applied to demonstrate the validity of the airflow and heat transfer routines in the simulation tool. In addition, coupled airflow and heat transfer in a fireplace is measured and simulated to validate the coupled airflow and heat transfer routines.