Airflow Modelling Software Development for Natural Ventilation Design - Green Building Environment Simulation Technology

Abstract

We developed natural ventilation simulation tool to provide an integration of BIM and CFD simulation in one simple, time efficient and cost effective solution. There are three main working procedures in this GrBEST developmental work. Firstly, we work with an Architect to prepare a clean BIM-REVIT model (IFC output) for GrBEST flow solver. A modelling protocol for REVIT base geometry creation was developed to help create a clean BIM-REVIT model (IFC output), allowing for seamless conversion algorithm to convert the primitive REVIT IFC file for GrBest flow solver. Secondly, a unique geometry handling tool to perform BIM conversion to CFD input file has also been developed. It involves the development of a new triangular mesh repair solution that automatically rectifies common geometrical and topological errors that are inherent in the processes of CAD modelling and simulation. Finally, we use an in-house CFD code and customize it for building ventilation simulation. GrBEST Flow Solver consists of UNIX executable modules to conduct meshing and incompressible CFD computation activities. Solver enhancement with immersed boundary method for building geometry adaptation has also been developed. This GrBEST software could promote building designers and architects to implement good natural ventilation strategies during conceptual planning and master design stage, and therefore resulting in larger impact towards urban sustainability effort in new town development.