Paper Conference

Proceedings of Building Simulation 2021: 17th Conference of IBPSA


Wind-driven air flow modelling in Modelica: verification and implementation in the IDEAS library

Klaas De Jonge 1,3, Filip Jorissen 2, Lieve Helsen 2,4, Jelle Laverge 1
1 Ghent University, Department of Architecture and Urban Planning , Belgium
2 University of Leuven (KU Leuven), Department of Mechanical Engineering, Belgium
3 FWO, Research Foundation Flanders
4 EnergyVille, Thor Park, Waterschei, Belgium

Abstract: In whole building simulations, interest in combined heat and air flow simulations is growing as this allows the investigation of indoor air quality (IAQ), HVAC energy use, and their interaction. To accomplish this, the user usually has to rely on co-simulation, which requires the user to be skilled in at least two software applications and in setting up the co-simulation environment. Additionally, often a large amount of input variables and parameters has to be entered twice. This paper presents an integrated pressure-driven air flow implementation in the opensource Modelica library IDEAS that allows easy and simultaneous modelling of combined building heat and air flow simulations. To verify the approach, a multi-zone IDEAS model is compared to (1) an equivalent CONTAM model to check the infiltration flow rates and (2) measured temperature data. This results in (1) mean absolute errors between 0.0037m3/h/m2 and 0.0057m3/h/m2 for infiltration volume flow rates per unit of envelope area ranging from - 0.74m3/h/m2 to 1.18m3/h/m2 and (2) root mean squared errors between 0.65°C and 1.1°C which is the same order of magnitude as the original IDEAS implementation. The new implementation allows the IDEAS library to be used for combined heat and air flow simulations with a minimum of additional effort.
Keywords: Modelica IDEAS, CONTAM, Pressure driven airflow, Indoor Air Quality, Indoor temperatures
Pages: 1099 - 1106