Expected and Available Results
The primary results of multizone airflow calculations are the flows for each conductance. For large openings, the two flows in either direction through the opening are calculated. From this, the following results can be derived (per time step):
• Flows: Total flow per zone, total outdoor airflow rate per zone, air change value per zone, outdoor air change value per zone, total outdoor airflow for building, total air change value for building
• Pressures: Pressure loss across link, zone pressures
• Contaminants: Concentration in the zones, cross-contamination effects
With simulation in time, using weather file and schedules, these results can be obtained:
• Evolution of airflow, air change and concentration values
• Average flow and air change values, histograms of airflow rate or concentration values, number of hours with airflows too low or too high, or with contaminant concentrations too high
• Maximum concentrations, integrated exposure values, inhaled dose values
Due to the methods and limitations outlined in Section 11.4.2, thermal comfort and draft risk evaluations cannot be performed using multizone airflow models. (From the flow across an opening, a rough estimate for the air velocity in the vicinity of the opening may be made.)
Due to the assumption of well-mixed air, room ventilation efficiency studies also cannot be performed. However, a multizone ventilation efficiency index for the whole building may be determined.
Without a thermal model, energy studies are also very limited (see Section 11.5).
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