VAV room temperature control cooling (VavTRCtlC11)

Overview

The application function "VAV room temperature control for cooling 11" (VavTRCtlC11) is the hub for the sequencing of the room temperature controllers for VAV cooling. It determines the room cooling setpoint and the room cooling demand signals to maintain the room temperature at the cooling setpoint.

The following devices in the room segment(s) are supported:

Cooling coil
Floor cooling
Chilled ceiling (panels or beams)
Supply air VAV damper

Function

This AF works in collaboration with a room segment HVAC device component AF for cooling. The cooling room temperature PID controller is enabled based on a signal that is read via the grouping function (from equipment in the room segment) indicating whether cooling is available.

Devices for cooling are activated in the following order (default):
Floor cooling > Chilled ceiling > Heating/Cooling coil > Cooling coil > VAV

Cooling setpoint and plant mode

	Plant operation mode	Cooling setpoint
1	Off	Protection cooling
2	Protection	Protection cooling
3	Economy	Economy cooling
4	Pre-Comfort	Pre-Comfort cooling
5	Comfort	Comfort cooling
6	Warm-up	Protection cooling
7	Cool down	Comfort / Pre-Comfort cooling¹
8	Room low temperature protection	Protection cooling
9	Not used
10	Free cooling	Comfort cooling
11	Night cooling	Comfort cooling
12	Ventilation	Comfort cooling
13	Not used
14	Air volume flow off	Protection cooling
15	Smoke extraction positive pressure	Protection cooling
16	Smoke extraction negative pressure	Protection cooling
17	Purge	Protection cooling

¹⁾ Depends on Next room operating mode (NxROpMod) in HvacPltMod AF.

Feature configuration

Feature selections for "Room HVAC coordination" are accessed via the Application configuration task in the Configuration component.

Feature (AF)	Feature description	Ref.
Trend for present cooling setpoint	None/Active	☑

Configuration

Objects

Description	Object	Type	Default value
Cooling setpoint for comfort ▶ Default command must be configured on priority level 17. 0...50 [°C], 32.0...122.0 [°F]	SpCCmf	APrcVal	24 [°C] 75.0 [°F]
Delta cooling setpoint for pre-comfort ▶ Delta between comfort and pre-comfort setpoints. 0...10 [K], 0.0...18.0 [°F]	DSpCPcf	ACnfVal	1 [K] 2.0 [°F]
Cooling setpoint for economy 0...50 [°C], 32.0...122.0 [°F]	SpCEco	ACnfVal	35 [°C] 85.0 [°F]
Cooling setpoint for protection 0...50 [°C], 32.0...122.0 [°F]	SpCPrt	ACnfVal	40 [°C] 104.0 [°F]

Parameters

Description	Parameter	Default value
VAV operation 0:Series 1:Parallel ▶ Parallel means Vav flow setpoint is influenced by valve position.	VavOp	2:Parallel
Offset for VAV start ▶ Vav flow temperature control gets a higher setpoint especially in series operation.	OfsVavStt	0 [K] 0.0 [°F]
Coil valve start position by parallel operation	CoilVlvSttPrl	10 [%]
Coil valve end position by parallel operation	CoilVlvEndPrl	100 [%]
VAV end speed by parallel operation ▶ These values are related to the demand signal, the actual setpoint for the vav control depends on the settings in the segment.	VavEndSpdPrl	50 [%]
Comfort configuration 1:None ▶ None, means no aggregate is activated depending on cooling demand. 2:Radiant devices ▶ Radiant device, means only radiant devices (e.g. Chilled ceiling) will be activated depending on cooling demand. 3:Air treatment devices ▶ Air treatment devices, means only air treatment devices (Cooling coil, Vav) will be activated depending on cooling demand. 4:Radiant & air treatment devices ▶ Radiant & air treatment devices, both will be activated depending on cooling demand.	CmfCnf	4:Radiant & air treatment devices
Pre-Comfort configuration Enumeration see CmfCnf	PcfCnf	4:Radiant & air treatment devices
Economy configuration Enumeration see CmfCnf	EcoCnf	4:Radiant & air treatment devices
Protection configuration Enumeration see CmfCnf	PrtCnf	4:Radiant & air treatment devices
Cool down configuration Enumeration see CmfCnf	CoolDnCnf	4:Radiant & air treatment devices
Free cooling configuration Enumeration see CmfCnf	FreeCCnf	4:Radiant & air treatment devices
Coil: Controller mode by comfort 0:Continuous 1:2-position ▶ 2-position, the output will be 0 or 100 % nothing between, be aware of delays.	CoilCmf	0:Continuous
Coil: Controller mode by pre-comfort Enumeration see CoilCmf	CoilPcf	0:Continuous
Coil: Controller mode by economy Enumeration see CoilCmf	CoilEco	0:Continuous
Coil: Controller mode by protection Enumeration see CoilCmf	CoilPrt	0:Continuous
Coil: Controller mode by cool down Enumeration see CoilCmf	CoilCoolDn	0:Continuous
Radiant devices: Controller mode by comfort Enumeration see CoilCmf	RadDevCmf	0:Continuous
Radiant devices: Controller mode by pre-comfort Enumeration see CoilCmf	RadDevPcf	0:Continuous
Radiant devices: Controller mode by economy Enumeration see CoilCmf	RadDevEco	0:Continuous
Radiant devices: Controller mode by protection Enumeration see CoilCmf	RadDevPrt	0:Continuous
Radiant devices: Controller mode by cool down Enumeration see CoilCmf	RadDevCoolDn	0:Continuous
Radiant floor cooling sequence	RfrCSeq	1 [1..8 unique]
Radiant ceiling cooling sequence	RcgCSeq	2 [1..8 unique]
Heating/cooling coil cooling sequence	HCclCSeq	3 [1..8 unique]
Cooling coil cooling sequence	CclCSeq	4 [1..8 unique]
VAV cooling sequence	VavCSeq	5 [1..8 unique]

Interface

Interface	Description	Type	Ref.	Owned by
PrSpC	Present cooling setpoint	APrcVal	●	-
TrndPrSpC	Trend for present cooling setpoint	FtrSel	☑	-
PrSpCCmf	Present cooling setpoint for comfort	ACalcVal	●	-
PrSpCPcf	Present cooling setpoint for pre-comfort	ACalcVal	●	-
PrSpCEco	Present cooling setpoint for economy	ACalcVal	●	-
PrSpCPrt	Present cooling setpoint for protection	ACalcVal	●	-
VavTRCtrC	Room temperature controller cooling for VAV	Controller	●	-
CclTRCtrC	Room temperature controller cooling for cooling coil	Controller	●	-
HCclTRCtrC	Room temperature controller cooling for heating/cooling coil	Controller	●	-
RcgTRCtrC	Room temperature controller cooling for radiant ceiling	Controller	●	-
RfrTRCtrC	Room temperature controller cooling for radiant floor	Controller	●	-
RCtl	Room control	GrpMaster	◉	Room
SpCCmf	Cooling setpoint for comfort	APrcVal	●	-
DSpCPcf	Delta cooling setpoint for pre-comfort	ACnfVal	●	-
SpCEco	Cooling setpoint for economy	ACnfVal	●	-
SpCPrt	Cooling setpoint for protection	ACnfVal	●	-

Engineering and commissioning

Radiant floor is likely to change room temperature slower than other HVAC equipment. For specific projects, it may be useful to slow down the action of the relevant room temperature controller (continuous, PID) or change the controller mode to 2-position.