Coupled simulation of indoor environment, HVAC and control system by using fast fluid dynamics and the Modelica Buildings Library

Ventilations with stratified air distributions are commonly used to reduce building energy consumption while improving the indoor environment quality. This paper describes the coupling of transient simulations of indoor environments with HVAC systems, controls and building envelope. The indoor environment was simulated using a fast fluid dynamics (FFD) simulation program. The building fabric heat transfer, HVAC and control system were modeled using the Modelica Buildings library. After presenting the concept, the mathematical algorithm and the implementation of the coupled simulation, two numerical examples of ventilation with natural convection and mixed convection in a single-room building are provided for validation and demonstration. Further research and development needs are also discussed.