The application function selects the HVAC plant operating mode (PltOpMod) and considers the room operating mode, presence detection, HVAC presence mode and window contact. Warmup and cool down request signals are received using the central operating system (e.g., Scheduler).
The VAV application templates support 17 different plant modes. The plant modes are provided to cover a wide variety of room applications.
NOTE:
If a specific plant mode is not used, it should not be enabled.
Enum |
Plant Mode |
Purpose |
Action of Mechanical Equipment |
Trigger(s) |
---|---|---|---|---|
1 |
Off |
Shutdown all heating, cooling and ventilation. |
All mechanical equipment turns off. |
manual command, or initial startup |
2 |
Building Protection |
Conserve energy in long term vacancy. To protect mechanical equipment from freezing or other adverse conditions. |
|
manual command or schedule
|
3 |
Economy |
Conserve energy during daily unoccupied period. |
Night setback/setup during unoccupied hours. Ventilation reduced or off selected by configuration. |
schedule/ occ sensor |
4 |
Pre-Comfort |
Conserve energy for brief unoccupied periods. |
Configurable. Example: Shut off ventilation for conference rooms that are unoccupied during the normally occupied daytime hours. |
schedule/ occ sensor
|
5 |
Comfort |
Provide room air conditions suitable for room occupancy. |
All space conditioning equipment runs in “automatic” to maintain desired space conditions during occupancy. |
schedule/ occ sensor or comfort button from room operating unit |
6 |
Warm-up |
Return to comfort conditions before occupancy |
Mechanical heating equipment starts before occupancy period begins. Comfort setpoints apply for temperature. Ventilation may be off. |
central command |
7 |
Cool-down |
Return to comfort conditions before occupancy |
Cooling equipment starts before occupancy period begins. Comfort setpoints apply for temperature. Ventilation may be off. |
central command |
8 |
Room temp. (frost) prot. |
Avoid damage in room by applying heat at high priority, overriding errant commands from outside the application |
not used in VAV |
|
9 |
Equipment temperature protection |
Avoid damage to equipment, such as frozen coils |
not used in VAV |
|
10 |
Free cooling |
Overcool past current demand to store energy |
Pre-cool building or zones beyond current setpoint during advantageous periods, storing energy in the thermal mass to reduce the need for cooling later. |
central command |
11 |
Night cooling |
Prevent build-up of heat in interior spaces during unoccupied hours. |
Cooling using 100% outside air during night time. |
central command |
12 |
Rapid ventilation |
Clear contaminated air with temporary high primary airflow |
Supply air flow goes to the max ventilation value. Temp control continues according to room op mode. |
manual command from room unit |
14 |
Fire (EmgOff) |
Isolate fire and smoke, preventing spread through the ventilation system |
Supply air damper closes. Exhaust air damper closes. |
External command to fire mode object. |
15 |
Smoke Positive press. |
Oppose infiltration of smoke to room from surrounding spaces |
Supply flow goes to a configured level. Extract damper closes. |
External command to fire mode object. |
16 |
Smoke Negative press. |
Oppose exfiltration of smoke from room to surrounding spaces |
Extract flow goes to a configured level. Supply damper closes, |
External command to fire mode object. |
17 |
Smoke Purge |
Clear smoke from the building after a fire |
Supply flow goes to largest of configured limits. Extract tracks normally. |
External command to fire mode object. |
The Table below shows the different room and central BAS functions that determine the plant mode for the VAV application templates.
NOTE:
If an input is not configured in the application, it is NOT USED in determining the plant mode state.
IF |
THEN | |||||
---|---|---|---|---|---|---|
Room operating mode
|
Presence detection
(Room Comfort Button) |
Window contact
(Room) |
Night cooling signal
(from Scheduler) |
Cool down signal
(from Scheduler) |
Warm-up signal
(from Scheduler) |
Plant mode |
- |
- |
Open |
- |
- |
- |
Protection |
Protection |
- |
Closed |
- |
- |
- |
Protection |
Economy |
- |
Closed |
False |
False |
False |
Economy |
- |
Closed |
True |
False |
False |
Night cooling | |
- |
Closed |
- |
- |
True |
Warm-up | |
- |
Closed |
- |
True |
False |
Cool down | |
Pre-Comfort |
- |
Closed |
- |
True |
- |
Cool down |
- |
Closed |
- |
False |
- |
Pre-Comfort | |
Present |
Closed |
- |
- |
- |
Comfort | |
Absent |
Closed |
- |
False |
- |
Pre-Comfort | |
Absent |
Closed |
- |
True |
- |
Cool down | |
Comfort |
- |
Closed |
- |
- |
- |
Comfort |
Present |
Closed |
- |
- |
- |
Comfort | |
Absent |
Closed |
- |
False |
- |
Pre-Comfort | |
Absent |
Closed |
- |
True |
- |
Cool down | |
|
Present |
Closed |
- |
- |
- |
Rapid Ventilation |