Modeling and simulation of a simple building energy system

A mathematical model for building energy systems (BES) is developed which maps the energy transfer processes occurring within the building space. Construction elements making up the building space and the heating and cooling plant responsible for thermal comfort of the occupants are also modeled. This involved quantification of linkages between temperature and humidity conditions and level occupancy (number of occupants, occupancy schedule) within building space. Thermal energy transfer processes of conductive, convective, and radiative heat balance for each surface of the construction elements and a convective heat balance for the building space are modeled. Building space zone is modelled for both sensible and latent thermal energy transfer. State space approach is used to model the building construction elements such as walls, with the parameters estimated using a nonlinear time invariant optimization algorithm with constraints. HVAC system is modelled with a control valve, heat emitter, occupancy driven ventilation controlled through a PID controller. A complete building energy system (BES) modeling procedure based on first principles of building physics is presented. BES model is simulated using MATLAB/Simulink and the results depict the temperature variations within the building space at less computational times.