Multi-floor building heating models in MATLAB and Modelica environments

Buildings are one of the largest energy consumers in the world. In northern countries, buildings consume most of the energy for space heating owing to the predominating cold climate conditions. Today there is a trend to use Building Energy Management Systems (BEMS) in buildings to make the indoor environment more comfortable and to utilise energy in a more efficient way. Currently, BEMS lack a building heating model, and the control is often based on temperature zones. Integration of a good building heating model with BEMS may assist in monitoring the heating of buildings in an optimal way while saving energy. Hence, the goal is to develop a model that can be applied in on-line control with acceptable performance and accuracy. This article covers multi-floor physics-based building heating models developed in MATLAB and Modelica environments. The Modelica model uses the model components from Modelica Buildings Library and is more complex than the MATLAB model. The applicability of the two models in on-line control in BEMS principally depends on the accuracy of the predictions and prediction time. The prediction accuracy of both models is satisfactory while the Modelica model is robust. With the used computational power, the MATLAB model provides faster results compared to the Modelica model. More real-time experiments are needed for both models, and they can be applied in on-line control, depending on the model simplicity, available computational power and real-time segments in the system. In addition, the methodology used in the MATLAB model development is application independent and can be implemented in different natures of building configurations.