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New Mass Transport Elements and Components for the NIST IAQ Model.


pdf icon New Mass Transport Elements and Components for the NIST IAQ Model. (5936 K)
Axley, J. W.

NIST GCR 95-676; 33 p. July 1995.

Sponsor:

National Institute of Standards and Technology, Gaithersburg, MD

Available from:

National Technical Information Service
Order number: PB95-255899

Keywords:

contaminant dispersal; filtration; indoor air quality; mass transport; modeling; ventilation

Abstract:

This report presents new mass transport elements for the next generation of the NIST IAQ Model that may be used to model [a] homogeneous (bulk-air) chemistry within well-mixed chamber, [b] aerosol mass transport within well-mixed chambers and fractional particle filtration in building filtration devices, and [c] heterogeneous (surface-related) physical processes and chemical transformations including those governing the behavior of gas-phase air cleaning devices. In an effort to maintain rigor, generality, and flexibility, each transport process is formulated in terms of the elemental mass transport steps that together govern the overall process. In this way, the more complex processes may be represented as component equations that are assembled from fundamental element equations. The element/component assembly method, upon which the NIST IAQ Model is based, provides a general and modular approach to the formulation of systems of equation governing the mass and air transport in buildings to effect indoor air quality analysis. In this approach, the solution of the system equations is a computationally distinct task that may be achieved using a variety of numerical methods. The third chapter of this report discusses numerical and computational strategies for the solution of the system equations that are compatible with both the existing and proposed new mass transport elements and presents candidate strategies that appear to be most promising. Finally the fourth chapter of this report considers user interface strategies to implement the proposed new mass transport elements and components.