NIST Multizone Modeling Website
User Tasks
The use of CONTAM to analyze airflow or contaminant migration in a building involves five distinct tasks:
1. Building Idealization: Form an idealization or specific model of the building being considered,
2. Schematic Representation: Develop a schematic representation of the idealized building using the CONTAMW SketchPad to draw the building components,
3. Define Building Components: Collect and input data associated with each of the building components represented on the SketchPad,
4. Simulation: Select the type of analysis you wish to conduct, set simulation parameters, and execute the simulation,
5. Review & Record Results: Review the results of your simulation and record selected portions of the results.
Task 1 - Building Idealization
Building idealization refers to the simplification of a building into a set of zones that are relevant to the user's goal in performing an analysis. A building can be idealized in a number of ways depending on the building layout, the ventilation system configuration and the problem of interest. This idealization phase of analysis requires some engineering knowledge on the part of the user and is an acquired skill that you can develop through experience in airflow and indoor air quality analysis and by becoming familiar with the theoretical principles and details upon which indoor air quality analysis is based.
Task 2 - SketchPad Representation
Developing the SketchPad representation will be the focus of your interaction with CONTAM. With CONTAM's SketchPad you will be able to draw a diagram - a SketchPad diagram - of your building idealization using drawing tools and libraries of icons to represent components of the building system. CONTAM translates your diagram into a system of equations that will than be used to model the behavior of the building when you perform a simulation.
Task 3 - Data Entry
Data entry can be one of the more time-consuming parts of the process of using CONTAM. It involves the determination and input of the numerical values of the parameters associated with each of the SketchPad icons. These icons represent the elements of the building model and include air leakage paths (windows, doors, cracks), ventilation system elements (fans, ducts, vents), contaminant sources, filters, and sinks. Each of these elements is associated with a number of parameters, and you must obtain the values of these parameters for entry into the model. Depending on the element and the application, these values can be obtained from building-specific data, engineering handbooks, and product literature. In many cases, a degree of engineering judgement will be involved. CONTAM allows you to create libraries of these elements that you can use in current and future modeling efforts.
Task 4 - Simulation
Simulation is the use of CONTAM to solve the system of equations assembled from your SketchPad representation of a building to predict the airflow and contaminant concentrations of interest. This step involves determining the type of analysis that is needed; steady state, transient or cyclical, and a number of other simulation parameters. These parameters depend on the type of analysis you wish to perform (steady state or transient), and include convergence criteria and in the case of a transient analysis, time steps and the duration of the analysis.
Task 5 - Review & Record Results
CONTAM allows the user to view the simulation results on the screen and to output them to a file for input to a spreadsheet program or a data analysis program developed by the user. Airflows and pressure differences at each flow element can be viewed directly on the SketchPad. Contaminant concentrations for a zone can also be plotted as a function of time directly from the SketchPad. The user can then decide which data they wish to examine more closely and export these to a tab-delimited text file that can then be imported into a spreadsheet for further analysis.
