General
Ventimental calculates airflow rates for mechanical ventilation systems using the methodologies of ASHRAE Standard 62.1 Section 6.2 - Ventilation Rate Procedure.
Multiple Zone Systems
For multiple‑zone systems, both constant air volume (CAV) and variable air volume (VAV), Ventimental calculates the required outdoor air ventilation rate using either the simplified method (ASHRAE 62.1 Section 6.2.4.3) or the alternative procedure (ASHRAE 62.1 Normative Appendix A).
Ventilation Rates
The outdoor air ventilation rates of ASHRAE 62.1 Table 6‑1 and the exhaust air ventilation rates of Table 6‑2 are combined in a single table. Selecting a space type (e.g., “Art Classroom”) automatically applies both the Table 6‑1 outdoor air rate and the Table 6‑2 exhaust air rate.
Ventilation rates for Outpatient Health Care Facilities from ASHRAE 62.1 Normative Appendix D Table D‑1 are also included.
Zone Templates
Zone templates can be created and assigned to multiple zones, allowing inputs such as floor area, occupancy type, and Ez to be reused. This reduces data entry and improves consistency for projects with repeated identical spaces such as small offices, classrooms, and restrooms.
Input
Zones are entered on worksheets separate from supply and exhaust fans, and each zone is assigned to one or both. This structure makes it easy to reassign zones between fans as needed.
Risers
Risers show cumulative airflow between floors for fans serving more than one level. Risers are created automatically based on the initial characters of zone numbers, as defined by the user.
Riser airflow may be upward, downward, or both, depending on the fan’s location relative to the floors it serves.
Groups
Fans can be grouped, allowing cumulative airflow rates for fan groups to be analyzed.
Critical Zones
Critical zones are highlighted for multiple‑zone systems, thereby simplifying the adjustments needed to optimize outdoor airflow rates.
Transfer Air
Ventimental supports transferring air from zones with outdoor air ventilation (or excess outdoor air) to zones requiring exhaust ventilation (or with excess exhaust).
Two transfer methods are supported: direct zone‑to‑zone transfer and indirect transfer via plenums. Indirect transfer is used when air must be transferred to more than two zones, because as implemented in Ventimental each zone can transfer air directly to only two other zones.
Plenums can represent above ceiling spaces, chases, passive or fan forced transfer air ductwork, or direct transfer air paths between zones such as door undercuts.
Features
Supports both Inch‑Pound (I‑P) and International System (SI) units.
480 zones.
30 zone templates.
30 supply fans.
30 exhaust fans.
8 user‑defined zone air distribution effectiveness factors.
16 user‑defined zone ventilation rates.
Risers for each fan and for 5 fan groups, up to 10 floors.
Air transfer between zones.
Metrics for analyzing and optimizing 100% outdoor air systems.
All data is editable.
Limitations
Neither the ASHRAE 62.1 Section 6.3 Indoor Air Quality (IAQ) Procedure nor the Section 6.4 Natural Ventilation Procedure are supported.
Air change rate methodologies are not supported; therefore, the ventilation methodologies of ASHRAE Standard 170 (Ventilation of Health Care Facilities) are not included.
While Ventimental tracks whether each zone is net positive, net negative, or neutral, it does not track pressure relationships between zones.