5.1.2 Air Flow Modeling
Simulate the interactions of building systems and analyze how they affect overall ventilation performance of exterior and/or interior pressurization differentials; with the goal to optimize the air flow, reduce energy needs for ventilation, and inform urban design, building massing and/or facade design. Models are also used to assist in fire safety analysis.
Computational Fluid Dynamics (CFD) models are used to analyze interior air flow conditions and thermal mass impact. Wind tunnel tests are used to determine wind loads on buildings, informing the building definition and façade design.
The input for CFD analysis is derived from 2D and 3D CAD files and information. To ensure computational efficiency, the building geometry must be simple to minimize computational cost (time) but accurate enough to represent the physics of the space. Boundary conditions must be defined in terms of ambient weather conditions (solar loading, wind pressure, temperature and humidity) and material thermal/physical properties.
Substantial savings are possible due to a process that optimizes the air flow performance and building design. There are also cost savings due to a more effective commissioning process that starts during concept design.
Gives a thorough understanding of the multiple, interacting factors that influence airflow and optimizes design calculations of air volume and set point temperatures; enabling savings in capital investment and system operating costs. Ability to confidently predict and eliminate airflow problems or hazards early in the design process.
CFD analysis and/or wind tunnel testing are required for tall buildings, double-skin façade design, or buildings that include a more complex and less predictable internal geometry. CFD models are very useful to optimize atrium, light well and courtyard design with respect to integrating natural ventilation concepts and quantifying thermal mass.
1.2.1 Natural Ventilation
1.2.8 Hybrid Ventilation