The application function VAV ventilation control 11 (VavVntCtl11) collaborates with VAV supply air terminal boxes for ventilation and/or room air quality control.
Note:
- Ventilation mode: The ventilation mode can be set per room operating mode to:
- Off
- Minimum (Constant air flow)
- Dcv (Demand controlled ventilation)*
- Dcv & Min (Demand controlled ventilation with a minimum air flow limit)*
- *) Room air quality sensor required in the room.
- Minimum ventilation setup: Minimum ventilation air flow settings should be greater than 7% of the largest maximum air flow setpoint value (typically cooling flow maximum, VavSuAirFlMaxC located in the segment AF VavSu.xx).
Ventilation mode, Ventilation setpoint (only available with room air quality sensor activated) and Minimum air volume flow need to be considered and set as a pair per Room Operating Mode (ROpMod).
Pair #1 (Comfort mode) | Comfort configuration (CmfCnf) |
|
Minimum room air volume flow for comfort (AirFlMinRCmf) |
| |
Setpoint room air quality for comfort | - | |
Pair #2 (Pre-Comfort mode) | Pre-Comfort configuration | Enumeration see CmfCnf |
Minimum room air volume flow for pre-comfort | Function see CmfCnf | |
Setpoint room air quality for pre-comfort | - | |
Pair #3 (Economy mode) | Economy configuration | Enumeration see CmfCnf |
Minimum room air volume flow for economy | Function see CmfCnf | |
Setpoint room air quality for economy | - | |
Pair #4 (Protection mode) | Protection configuration | Enumeration see CmfCnf |
Minimum room air volume flow for protection | Function see CmfCnf | |
Setpoint room air quality for protection | - |
Example of parameters setting 1#:
In this example, assume AirFlNom and VavSuAirFlMaxC have both been set to 1000 m3/h, and the minimum ventilation setpoint object (VavSuAflMinVnt, located in the segment AF VavSu.xx) has been set to zero. Setting VavSuAflMinVnt in the segment AF to zero allows the min vent parameter settings in this AF (VAV ventilation control, VavVntCtl11) to vary per the room operating mode (Comfort, Pre-Comfort, Economy, Protection). See the following table.
Room mode ventilation flow value | Ventilation mode setting | Result |
|---|---|---|
AirFlMinRCmf = 100 m3/h | CmfCnf = Min vent & DCV | In Comfort, ventilation flow will have a low limit of 100 m3/h and may rise with air quality demand (DCV). |
AirFlMinRPcf = 80 m3/h | PcfCnf = Min vent | In Pre-Comfort, ventilation flow = 80 m3/h. |
AirFlMinREco = 60 m3/h | EcoCnf = Min vent | In Economy, ventilation flow will be zero, because AirFlMinREco was incorrectly set to 60 m3/h which is less than 7% of AirFlNom (AirFlNom was set to 1000 m3/h). |
AirFlMinRPrt = 80 m3/h | PrtCnf = Off | In Protection, the mode setting (PrtCnf) has been set to Off. When a ventilation mode setting = Off, ventilation flow for that room mode will be zero regardless of the parameter flow value (in this case, AirFlMinRPrt) or the value of VavSuAflMinVnt. |
Example of parameters setting 2#:
In this example, assume AirFlNom and VavSuAirFlMaxC have both been set to 1000 m3/h, and the minimum ventilation setpoint object (VavSuAflMinVnt) located in the segment AF VavSu.xx has been set to 100 m3/h.
Room mode ventilation flow value | Ventilation mode setting | Result |
|---|---|---|
AirFlMinRCmf = 125 m3/h | CmfCnf = Min vent | In Comfort, ventilation flow will be 125 m3/h. |
AirFlMinRPcf = 90 m3/h | PcfCnf = Min vent | In Pre-Comfort, ventilation flow = 100 m3/h (not 90) because VavSuAflMinVnt was set to 100, which is larger than 90; (90 and 100 are each >7% AirFlNom, so they are both valid (usable) values; when valid settings conflict, the larger value wins). |
AirFlMinREco = 50 m3/h | EcoCnf = Min vent | In Economy, ventilation flow will = 100 m3/h because VavSuAflMinVnt was set to 100. |
AirFlMinRPrt = 50 m3/h | PrtCnf = Off | In Protection, the mode setting (PrtCnf) has been set to Off. When a ventilation mode setting = Off, ventilation flow for that room mode will be zero regardless of the parameter flow value (in this case, AirFlMinRPrt) or the value of VavSuAflMinVnt. |
Example of use case 1#:
No room air quality sensor is required in the room. A minimum air volume flow is required for Economy mode but not for Pre-comfort mode or protection mode.
Pair #1 (Comfort mode) | Comfort configuration (CmfCnf) | Equals 4:Minimum ventilation & Demand-controlled ventilation (default setting), or 2:Minimum ventilation (the same behavior with 4:Minimum ventilation & Demand-controlled ventilation in this use case). |
Minimum room air volume flow for comfort (AirFlMinRCmf) | Required setpoint, but note that air flow minimum settings should be at least 7% of the largest maximum flow setpoint (VavSuAirFlMaxH\VavSuAirFlMaxC\VavSuAflMaxVnt). | |
Setpoint room air quality for comfort | No need to set as there is no sensor in room | |
Pair #3 (Economy mode) | Economy configuration | Equals 2: Minimum ventilation. |
Minimum room air volume flow for economy | Required setpoint, but note that air flow minimum settings should be at least 7% of the largest maximum flow setpoint (VavSuAirFlMaxH\VavSuAirFlMaxC\VavSuAflMaxVnt). | |
Setpoint room air quality for economy | No need to set as there is no sensor in room |
Example of use case 2#:
If a room air quality sensor is installed in room, air quality needs to be controlled by DXR1, then additional setting “Setpoint room air quality for comfort \ pre-comfort \ economy \ protection” needs to be considered and set.
Note: If room air quality control is activated, the final air volume flow output located in the segment AF VavSu.xx will select the maximum result from cooling\heating\ventilation.