The adaptive conflation of computational fluid dynamics with whole-building thermal simulation

An adaptive controller was devised and implemented within the ESP-r simulation program to support the conflation of CFD with dynamic whole-building thermal simulation. This controller manages all interactions between the thermal and CFD modelling domains. It incorporates the latest turbulence modelling advancements applicable for room air flow simulation and possesses a suite of handshaking and thermal boundary condition treatments. The controller is based upon a double-pass modelling approach. Each time-step that the thermal domain handshakes with CFD, an investigative simulation is performed to approximate the room’s flow and temperature field. Using these estimates the controller determines the nature of the flow (forced, buoyant, mixed, fully turbulent, weakly turbulent) adjacent to each surface. This information is used to select suitable boundary condition treatments for each surface. A second CFD simulation is then performed using the refined modelling approach to more accurately resolve the room’s air flow and temperature distribution, and to predict surface convection.