Addressing Indoor Air Quality Issues in Buildings Using Computational Fluid Dynamics

Published

February 1, 1999

Author(s)

Amy Musser

Abstract

Recent advances in Computational Fluid Dynamics (CFD) and in computing technology have simplified user interfaces and reduced the time required to predict the details of contaminant concentrations in enclosures, allowing indoor air quality issues in buildings to be investigated. However, widespread adoption by the design community will not occur until simulation tools can demonstrate sufficiently accurate, cost-effective results for practical problems. This goal requires the development of simplified methods for estimating the complex boundary conditions that govern heat and contaminant transfer in rooms, while seeking to minimize the necessary investment in computing and input time, specialized employee training, and hardware and software requirements. This research project seeks to address these issues and identify methods that will allow CFD to be applied dueing the design process. The appropriateness of a large eddy simulations of a large eddy simulation CFD program (McGratten et.al. 1994), developed at NIST to simulate the movement of smoke and hot gasses fires, will be demonstrated for modeling indoor air quality and thermal comfort during the first phase of this project. Initial comparisons with experimental data collected in a controlled environmental test chamber (Yuan et.al. 1998) have produced encouraging results, while identifying the importance of issues such as representation of boundary conditions at the inlet diffuser and modeling of the heat transfer boundary condition at room walls. Future work will include modeling of rooms located within real buildings, in which flow and contaminant boundary conditions are not precisely specified. The whole-building multizone model CONTAM (Walton 1994), developed at NIST to predict bulk air flow and contaminant transport between rooms of a building, will be used to estimate contaminant concentrations and flow to and from adjacent rooms, by assuming these zones to be perfectly mixed. These predictions will then serve to provide approximate boundary conditions for the room to be analyzed in more detail using CFD. Results obtained using this modeling strategy will then be compared to tracer gas experiments performed in a full scale building.Potential applications of CFD modeling used in conjunction with multizone modeling exist in nearly every type of construction, ranging from office buildings and residences to industrial applications and cleanroom facilities. Such a technique would allow the ventilation effectiveness associated with various systems, supply and return types and locations, as well as room geometry to be assessed for rooms in real buildings. Predicted contaminant levels throughout a room could be used to select an appropriate location for indoor air quality sensors, establish ventilation rates to dilute contaminants in an occupied or critical region, and estimate exposure to contaminants of known source. In addition, these techniques could also be utilized to evaluate thermal comfort for large, complex or stratified spaces.

Citation

Addressing Indoor Air Quality Issues in Buildings Using Computational Fluid Dynamics

Pub Type

Others

Keywords

building technology, computation fluid dynamics, computer simulation, containment dispersal, indoor air quality, large eddy simulation, multizone analysis, room airflow modeling, ventilation

Citation

Musser, A. (1999), Addressing Indoor Air Quality Issues in Buildings Using Computational Fluid Dynamics, Addressing Indoor Air Quality Issues in Buildings Using Computational Fluid Dynamics (Accessed April 25, 2024)