Integrated Building Physics Simulation with Femlab/simulink/matlab

The combined MatLab toolboxes FemLab and Simulink are evaluated as solvers for problems based on partial differential equations (PDEs). The FemLab software is designed to simulate systems of coupled PDEs, 1D, 2D or 3D, non-linear and time dependent. In order to show how the program works, a complete code for solving a 2D airflow problem is given. A validation study of this 2D dynamic airflow problem, modeled using Navier Stokes and buoyancy is shown. All results show good agreements with measurements. The following integrated building models are discussed: 1) A detailed case study on the combination of an indoor airflow model in FemLab connected to an on/off controller in Simulink. In this case, the code of a FemLab model is implemented in the discrete section of a S-Function of SimuLink, so that the specialized solvers of FemLab can be used. 2) Other already developed integrated building physics models in SimuLink are briefly discussed. These include a) a multi zone Heat Air and Moisture (HAM) indoor climate model, integration of this model with b) a thermal bridge model and controller and c) a moisture transport model and controller. At the conclusion the applications and the possible benefits for scientists, engineers and designers are discussed.