Buildings.Controls.OBC.ASHRAE.G36_PR1.AHUs.SingleZone.VAV.SetPoints
Output setpoints for AHU control
Information
This package contains sequences generating setpoints for single zone VAV AHU control.
Package Content
| Name | Description |
|---|---|
 ExhaustDamper
|
Control of actuated exhaust dampers without fans |
 ModeAndSetPoints
|
Output zone setpoint with operation mode selection |
 OutsideAirFlow
|
Output the minimum outdoor airflow rate setpoint for systems with a single zone |
 Supply
|
Supply air set point for single zone VAV system |
 Validation
|
Collection of validation models |
Buildings.Controls.OBC.ASHRAE.G36_PR1.AHUs.SingleZone.VAV.SetPoints.ExhaustDamper
Control of actuated exhaust dampers without fans
Information
Control sequence for exhaust dampers without fans. It is implemented according to ASHRAE Guidline 35 (G36), PART 5.N.8.(for multi zone VAV AHU), PART 5.P.6 and PART3.2B.3 (for single zone VAV AHU).
Single zone VAV AHU: Control of actuated exhaust dampers without fans (PART 5.P.6)
- Exhaust damper position setpoints (PART3.2B.3)
minExhDamPosis the exhaust damper position that maintains a building pressure of 12 Pa (0.05 inchWC) while the system is atminOutPosMin(i.e., the economizer damper is positioned to provide minimum outdoor air while the supply fan is at minimum speed).-
maxExhDamPosis the exhaust damper position that maintains a building pressure of 12 Pa (0.05 inchWC) while the economizer damper is fully open and the fan speed is at cooling maximum.
-
The exhaust damper is enabled when the associated supply fan is proven on and
any outdoor air damper is open
uOutDamPos > 0and disabled and closed otherwise. -
The exhaust damper position is reset linearly from
minExhDamPostomaxExhDamPosas the commanded economizer damper position goes fromminOutPosMintooutDamPhyPosMax.
The control sequence is as follows:
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Nominal parameters | |||
| Real | minExhDamPos | 0.2 | Exhaust damper position maintaining building static pressure at setpoint when the system is at minPosMin [1] |
| Real | maxExhDamPos | 0.9 | Exhaust damper position maintaining building static pressure at setpoint when outdoor air damper is fully open and fan speed is at cooling maximum [1] |
| Real | minOutPosMin | 0.4 | Outdoor air damper position when fan operating at minimum speed to supply minimum outdoor air flow [1] |
| Real | outDamPhyPosMax | 1 | Physical or at the comissioning fixed maximum position of the outdoor air damper [1] |
Connectors
| Type | Name | Description |
|---|---|---|
| input BooleanInput | uSupFan | Supply fan status |
| input RealInput | uOutDamPos | Outdoor air damper position [1] |
| output RealOutput | yExhDamPos | Exhaust damper position [1] |
Modelica definition
block ExhaustDamper
"Control of actuated exhaust dampers without fans"
parameter Real minExhDamPos(
min=0,
max=1,
final unit="1") = 0.2
"Exhaust damper position maintaining building static pressure at setpoint when the system is at minPosMin";
parameter Real maxExhDamPos(
min=0,
max=1,
final unit="1") = 0.9
"Exhaust damper position maintaining building static pressure at setpoint when outdoor air damper is fully open and fan speed is at cooling maximum";
parameter Real minOutPosMin(
min=0,
max=1,
final unit="1") = 0.4
"Outdoor air damper position when fan operating at minimum speed to supply minimum outdoor air flow";
parameter Real outDamPhyPosMax(
min=0,
max=1,
final unit="1")=1
"Physical or at the comissioning fixed maximum position of the outdoor air damper";
Buildings.Controls.OBC.CDL.Interfaces.BooleanInput uSupFan "Supply fan status";
Buildings.Controls.OBC.CDL.Interfaces.RealInput uOutDamPos(
min=0,
max=1,
final unit="1")
"Outdoor air damper position";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput yExhDamPos(
min=0,
max=1,
final unit="1") "Exhaust damper position";
Buildings.Controls.OBC.CDL.Continuous.Line exhDamPos
"Linearly map exhaust damper position to the outdoor air damper position";
Buildings.Controls.OBC.CDL.Continuous.Switch swi1
"Check if exhaust damper should be open";
Buildings.Controls.OBC.CDL.Continuous.Hysteresis greThr(
final uLow=0.02,
final uHigh=0.05)
"Check if outdoor air damper is open";
Buildings.Controls.OBC.CDL.Logical.And and2
"Check if exhaust damper should be activated";
protected
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant zerDam(
final k=0)
"Close damper when disabled";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant minExhDam(
final k=minExhDamPos)
"Exhaust damper position maintaining building static pressure at setpoint while the system is at minPosMin";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant maxExhDam(
final k=maxExhDamPos)
"Exhaust damper position maintaining building static pressure at setpoint when outdoor air damper is fully open and fan speed is at cooling maximum";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant minPosAtMinSpd(
final k=minOutPosMin)
"Outdoor air damper position when fan operating at minimum speed to supply minimum outdoor air flow";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant outDamPhyPosMaxSig(
final k=outDamPhyPosMax)
"Physical or at the comissioning fixed maximum position of the outdoor air damper";
equation
connect(outDamPhyPosMaxSig.y, exhDamPos.x2);
connect(maxExhDam.y, exhDamPos.f2);
connect(uOutDamPos, exhDamPos.u);
connect(zerDam.y, swi1.u3);
connect(and2.y, swi1.u2);
connect(minPosAtMinSpd.y, exhDamPos.x1);
connect(minExhDam.y, exhDamPos.f1);
connect(uOutDamPos, greThr.u);
connect(uSupFan, and2.u2);
connect(greThr.y, and2.u1);
connect(exhDamPos.y, swi1.u1);
connect(swi1.y, yExhDamPos);
end ExhaustDamper;
Buildings.Controls.OBC.ASHRAE.G36_PR1.AHUs.SingleZone.VAV.SetPoints.ModeAndSetPoints
Output zone setpoint with operation mode selection
Information
Block that outputs the zone setpoint temperature (TZonCooSet,
TZonHeaSet) and system operation mode (yOpeMod).
The sequence consists of the following two subsequences.
Operation mode selector
The subsequence outputs one of seven types of system operation mode (occupied, warm-up,
cooldown, setback, freeze protection setback, setup, unoccupied) according
to current time, the time to next occupied hours tNexOcc and
current zone temperature TZon.
See
Buildings.Controls.OBC.ASHRAE.G36_PR1.Generic.SetPoints.OperationMode.
Zone setpoint temperature reset
It sets the zone temperature setpoint according to the globally specified setpoints, the local setpoint adjustments, the demand limits adjustment, the window status and the occupancy status. See Buildings.Controls.OBC.ASHRAE.G36_PR1.TerminalUnits.SetPoints.ZoneTemperatures.
Usage
This version is for a single zone only to be used in the Single Zone VAV sequence.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Boolean | have_winSen | Check if the zone has window status sensor | |
| Boolean | have_occSen | Check if the zone has occupancy sensor | |
| Setpoints | |||
| Real | THeaSetOcc | 293.15 | Occupied heating setpoint [K] |
| Real | THeaSetUno | 285.15 | Unoccupied heating setpoint [K] |
| Real | TCooSetOcc | 297.15 | Occupied cooling setpoint [K] |
| Real | TCooSetUno | 303.15 | Unoccupied cooling setpoint [K] |
| Setpoints adjustment | |||
| Adjustable settings | |||
| Boolean | cooAdj | false | Flag, set to true if both cooling and heating setpoint are adjustable separately |
| Boolean | heaAdj | false | Flag, set to true if heating setpoint is adjustable |
| Boolean | sinAdj | false | Flag, set to true if both cooling and heating setpoint are adjustable through a single common knob |
| Boolean | ignDemLim | false | Flag, set to true to exempt individual zone from demand limit setpoint adjustment |
| Limits | |||
| Real | TZonCooOnMax | 300.15 | Maximum cooling setpoint during on [K] |
| Real | TZonCooOnMin | 295.15 | Minimum cooling setpoint during on [K] |
| Real | TZonHeaOnMax | 295.15 | Maximum heating setpoint during on [K] |
| Real | TZonHeaOnMin | 291.15 | Minimum heating setpoint during on [K] |
| Real | TZonCooSetWinOpe | 322.15 | Cooling setpoint when window is open [K] |
| Real | TZonHeaSetWinOpe | 277.15 | Heating setpoint when window is open [K] |
| Demand control adjustment | |||
| Real | incTSetDem_1 | 0.56 | Cooling setpoint increase value (degC) when cooling demand limit level 1 is imposed |
| Real | incTSetDem_2 | 1.1 | Cooling setpoint increase value (degC) when cooling demand limit level 2 is imposed |
| Real | incTSetDem_3 | 2.2 | Cooling setpoint increase value (degC) when cooling demand limit level 3 is imposed |
| Real | decTSetDem_1 | 0.56 | Heating setpoint decrease value (degC) when heating demand limit level 1 is imposed |
| Real | decTSetDem_2 | 1.1 | Heating setpoint decrease value (degC) when heating demand limit level 2 is imposed |
| Real | decTSetDem_3 | 2.2 | Heating setpoint decrease value (degC) when heating demand limit level 3 is imposed |
| Advanced | |||
| Real | bouLim | 1 | Threshold of temperature difference for indicating the end of setback or setup mode |
| Real | uLow | -0.1 | Low limit of the hysteresis for checking temperature difference |
| Real | uHigh | 0.1 | High limit of the hysteresis for checking temperature difference |
| Operation mode | |||
| Real | preWarCooTim | 10800 | Maximum cool-down or warm-up time [s] |
| Real | TZonFreProOn | 277.15 | Threshold temperature to activate the freeze protection mode [K] |
| Real | TZonFreProOff | 280.15 | Threshold temperature to end the freeze protection mode [K] |
Connectors
| Type | Name | Description |
|---|---|---|
| input RealInput | cooDowTim | Cool-down time retrieved from optimal cool-down block [s] |
| input RealInput | warUpTim | Warm-up time retrieved from optimal warm-up block [s] |
| input BooleanInput | uWin | Window status: true=open, false=close |
| input RealInput | TZon | Zone temperature [K] |
| input BooleanInput | uOcc | Zone occupancy status according to the schedule: true=occupied, false=unoccupied |
| input RealInput | tNexOcc | Time to next occupied period [s] |
| input RealInput | setAdj | Setpoint adjustment value |
| input RealInput | heaSetAdj | Heating setpoint adjustment value |
| input BooleanInput | uOccSen | Occupancy sensor (occupied=true, unoccupied=false) |
| input IntegerInput | uCooDemLimLev | Cooling demand limit level |
| input IntegerInput | uHeaDemLimLev | Heating demand limit level |
| output IntegerOutput | yOpeMod | Operation mode |
| output RealOutput | TZonCooSet | Cooling setpoint temperature [K] |
| output RealOutput | TZonHeaSet | Heating setpoint temperature [K] |
Modelica definition
block ModeAndSetPoints "Output zone setpoint with operation mode selection"
parameter Boolean have_winSen "Check if the zone has window status sensor";
parameter Boolean have_occSen "Check if the zone has occupancy sensor";
parameter Real THeaSetOcc(
final unit="K",
displayUnit="degC",
final quantity="ThermodynamicTemperature")=293.15
"Occupied heating setpoint";
parameter Real THeaSetUno(
final unit="K",
displayUnit="degC",
final quantity="ThermodynamicTemperature")=285.15
"Unoccupied heating setpoint";
parameter Real TCooSetOcc(
final unit="K",
displayUnit="degC",
final quantity="ThermodynamicTemperature")=297.15
"Occupied cooling setpoint";
parameter Real TCooSetUno(
final unit="K",
displayUnit="degC",
final quantity="ThermodynamicTemperature")=303.15
"Unoccupied cooling setpoint";
parameter Boolean cooAdj=false
"Flag, set to true if both cooling and heating setpoint are adjustable separately";
parameter Boolean heaAdj=false
"Flag, set to true if heating setpoint is adjustable";
parameter Boolean sinAdj=false
"Flag, set to true if both cooling and heating setpoint are adjustable through a single common knob";
parameter Boolean ignDemLim=false
"Flag, set to true to exempt individual zone from demand limit setpoint adjustment";
parameter Real TZonCooOnMax(
final unit="K",
displayUnit="degC",
final quantity="ThermodynamicTemperature")=300.15
"Maximum cooling setpoint during on";
parameter Real TZonCooOnMin(
final unit="K",
displayUnit="degC",
final quantity="ThermodynamicTemperature")=295.15
"Minimum cooling setpoint during on";
parameter Real TZonHeaOnMax(
final unit="K",
displayUnit="degC",
final quantity="ThermodynamicTemperature")=295.15
"Maximum heating setpoint during on";
parameter Real TZonHeaOnMin(
final unit="K",
displayUnit="degC",
final quantity="ThermodynamicTemperature")=291.15
"Minimum heating setpoint during on";
parameter Real TZonCooSetWinOpe(
final unit="K",
displayUnit="degC",
final quantity="ThermodynamicTemperature")=322.15 "Cooling setpoint when window is open";
parameter Real TZonHeaSetWinOpe(
final unit="K",
displayUnit="degC",
final quantity="ThermodynamicTemperature")=277.15 "Heating setpoint when window is open";
parameter Real incTSetDem_1=0.56
"Cooling setpoint increase value (degC) when cooling demand limit level 1 is imposed";
parameter Real incTSetDem_2=1.1
"Cooling setpoint increase value (degC) when cooling demand limit level 2 is imposed";
parameter Real incTSetDem_3=2.2
"Cooling setpoint increase value (degC) when cooling demand limit level 3 is imposed";
parameter Real decTSetDem_1=0.56
"Heating setpoint decrease value (degC) when heating demand limit level 1 is imposed";
parameter Real decTSetDem_2=1.1
"Heating setpoint decrease value (degC) when heating demand limit level 2 is imposed";
parameter Real decTSetDem_3=2.2
"Heating setpoint decrease value (degC) when heating demand limit level 3 is imposed";
parameter Real bouLim=1
"Threshold of temperature difference for indicating the end of setback or setup mode";
parameter Real uLow=-0.1
"Low limit of the hysteresis for checking temperature difference";
parameter Real uHigh=0.1
"High limit of the hysteresis for checking temperature difference";
parameter Real preWarCooTim(
final unit="s",
final quantity="Time")=10800 "Maximum cool-down or warm-up time";
parameter Real TZonFreProOn(
final unit="K",
displayUnit="degC",
final quantity="ThermodynamicTemperature")=277.15
"Threshold temperature to activate the freeze protection mode";
parameter Real TZonFreProOff(
final unit="K",
displayUnit="degC",
final quantity="ThermodynamicTemperature")=280.15
"Threshold temperature to end the freeze protection mode";
Buildings.Controls.OBC.CDL.Interfaces.RealInput cooDowTim(
final unit="s",
final quantity="Time")
"Cool-down time retrieved from optimal cool-down block";
Buildings.Controls.OBC.CDL.Interfaces.RealInput warUpTim(
final unit="s",
final quantity="Time") "Warm-up time retrieved from optimal warm-up block";
Buildings.Controls.OBC.CDL.Interfaces.BooleanInput uWin if have_winSen
"Window status: true=open, false=close";
Buildings.Controls.OBC.CDL.Interfaces.RealInput TZon(
final unit="K",
displayUnit="degC",
final quantity="ThermodynamicTemperature")
"Zone temperature";
Buildings.Controls.OBC.CDL.Interfaces.BooleanInput uOcc
"Zone occupancy status according to the schedule: true=occupied, false=unoccupied";
Buildings.Controls.OBC.CDL.Interfaces.RealInput tNexOcc(
final unit="s",
final quantity="Time") "Time to next occupied period";
Buildings.Controls.OBC.CDL.Interfaces.RealInput setAdj if cooAdj or sinAdj
"Setpoint adjustment value";
Buildings.Controls.OBC.CDL.Interfaces.RealInput heaSetAdj if heaAdj
"Heating setpoint adjustment value";
Buildings.Controls.OBC.CDL.Interfaces.BooleanInput uOccSen if have_occSen
"Occupancy sensor (occupied=true, unoccupied=false)";
Buildings.Controls.OBC.CDL.Interfaces.IntegerInput uCooDemLimLev
"Cooling demand limit level";
Buildings.Controls.OBC.CDL.Interfaces.IntegerInput uHeaDemLimLev
"Heating demand limit level";
Buildings.Controls.OBC.CDL.Interfaces.IntegerOutput yOpeMod "Operation mode";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput TZonCooSet(
final unit="K",
displayUnit="degC",
final quantity="ThermodynamicTemperature")
"Cooling setpoint temperature";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput TZonHeaSet(
final unit="K",
displayUnit="degC",
final quantity="ThermodynamicTemperature")
"Heating setpoint temperature";
Buildings.Controls.OBC.ASHRAE.G36_PR1.Generic.SetPoints.OperationMode
opeModSel(
final numZon=1,
final preWarCooTim=preWarCooTim,
final TZonFreProOn=TZonFreProOn,
final TZonFreProOff=TZonFreProOff) "Operation mode";
Buildings.Controls.OBC.ASHRAE.G36_PR1.TerminalUnits.SetPoints.ZoneTemperatures
TZonSet(
final have_occSen=have_occSen,
final have_winSen=have_winSen,
final cooAdj=cooAdj,
final heaAdj=heaAdj,
final sinAdj=sinAdj,
final ignDemLim=ignDemLim,
final TZonCooOnMax=TZonCooOnMax,
final TZonCooOnMin=TZonCooOnMin,
final TZonHeaOnMax=TZonHeaOnMax,
final TZonHeaOnMin=TZonHeaOnMin,
final TZonCooSetWinOpe=TZonCooSetWinOpe,
final TZonHeaSetWinOpe=TZonHeaSetWinOpe,
final incTSetDem_1=incTSetDem_1,
final incTSetDem_2=incTSetDem_2,
final incTSetDem_3=incTSetDem_3,
final decTSetDem_1=decTSetDem_1,
final decTSetDem_2=decTSetDem_2,
final decTSetDem_3=decTSetDem_3) "Adjust setpoint temperature";
Buildings.Controls.OBC.ASHRAE.G36_PR1.Generic.SetPoints.ZoneStatus zonSta(
final THeaSetOcc=THeaSetOcc,
final THeaSetUno=THeaSetUno,
final TCooSetOcc=TCooSetOcc,
final TCooSetUno=TCooSetUno,
final bouLim=bouLim,
final have_winSen=have_winSen,
final uLow=uLow,
final uHigh=uHigh) "Zone temperature status";
Buildings.Controls.OBC.CDL.Conversions.BooleanToInteger colZon
"Check if the zone is cold";
Buildings.Controls.OBC.CDL.Conversions.BooleanToInteger hotZon
"Check if the zone is hot";
Buildings.Controls.OBC.CDL.Logical.Sources.Constant winSta(
final k=false) if not have_winSen
"Assume window is closed when there is no windows status sensor";
Buildings.Controls.OBC.CDL.Logical.Sources.Constant occSta(
final k=true) if not have_occSen
"Assume the zone is occupied when there is no occupancy sensor";
Buildings.Controls.OBC.CDL.Conversions.BooleanToInteger booToInt
"Boolean to integer";
equation
connect(zonSta.cooDowTim, cooDowTim);
connect(zonSta.warUpTim, warUpTim);
connect(zonSta.uWin, uWin);
connect(zonSta.TZon, TZon);
connect(zonSta.yCooTim, opeModSel.maxCooDowTim);
connect(zonSta.yWarTim, opeModSel.maxWarUpTim);
connect(zonSta.yHigOccCoo, opeModSel.uHigOccCoo);
connect(zonSta.yOccHeaHig, opeModSel.uOccHeaHig);
connect(zonSta.yUnoHeaHig, colZon.u);
connect(colZon.y, opeModSel.totColZon);
connect(zonSta.yHigUnoCoo, hotZon.u);
connect(hotZon.y, opeModSel.totHotZon);
connect(zonSta.yUnoHeaHig, opeModSel.uSetBac);
connect(zonSta.yEndSetBac, opeModSel.uEndSetBac);
connect(TZon, opeModSel.TZonMin);
connect(zonSta.yHigUnoCoo, opeModSel.uSetUp);
connect(zonSta.yEndSetUp, opeModSel.uEndSetUp);
connect(opeModSel.uOcc, uOcc);
connect(opeModSel.tNexOcc, tNexOcc);
connect(zonSta.TCooSetOn, TZonSet.TZonCooSetOcc);
connect(zonSta.TCooSetOff, TZonSet.TZonCooSetUno);
connect(zonSta.THeaSetOn, TZonSet.TZonHeaSetOcc);
connect(zonSta.THeaSetOff, TZonSet.TZonHeaSetUno);
connect(opeModSel.yOpeMod, TZonSet.uOpeMod);
connect(TZonSet.uCooDemLimLev, uCooDemLimLev);
connect(TZonSet.uHeaDemLimLev, uHeaDemLimLev);
connect(uWin, TZonSet.uWinSta);
connect(winSta.y, TZonSet.uWinSta);
connect(TZonSet.uOccSen, uOccSen);
connect(occSta.y, TZonSet.uOccSen);
connect(opeModSel.yOpeMod, yOpeMod);
connect(TZonSet.TZonCooSet, TZonCooSet);
connect(TZonSet.TZonHeaSet, TZonHeaSet);
connect(winSta.y, booToInt.u);
connect(uWin, booToInt.u);
connect(booToInt.y, opeModSel.uOpeWin);
connect(TZonSet.setAdj, setAdj);
connect(TZonSet.heaSetAdj, heaSetAdj);
end ModeAndSetPoints;
Buildings.Controls.OBC.ASHRAE.G36_PR1.AHUs.SingleZone.VAV.SetPoints.OutsideAirFlow
Output the minimum outdoor airflow rate setpoint for systems with a single zone
Information
This atomic sequence sets the minimum outdoor airflow setpoint for compliance with the ventilation rate procedure of ASHRAE 62.1-2013. The implementation is according to ASHRAE Guidline 36 (G36), PART 5.P.4.b, PART 5.B.2.b, PART3.1-D.2.a.
Step 1: Minimum breathing zone outdoor airflow required breZon
- The area component of the breathing zone outdoor airflow:
breZonAre = AFlo*VOutPerAre_flow. - The population component of the breathing zone outdoor airflow:
breZonPop = occCou*VOutPerPer_flow.
The number of occupant occCou could be retrieved
directly from occupancy sensor nOcc if the sensor exists
(have_occSen=true), or using the default occupant density
occDen to find it AFlo*occDen. The occupant
density can be found from Table 6.2.2.1 in ASHRAE Standard 62.1-2013.
Step 2: Zone air-distribution effectiveness zonDisEff
Table 6.2.2.2 in ASHRAE 62.1-2013 lists some typical values for setting the
effectiveness. Depending on difference between zone space temperature
TZon and supply air temperature TDis, Warm-air
effectiveness zonDisEffHea or Cool-air effectiveness
zonDisEffCoo should be applied.
Step 3: Minimum required zone outdoor airflow zonOutAirRate
For each zone in any mode other than occupied mode and for zones that have
window switches and the window is open, zonOutAirRate shall be
zero.
Otherwise, the required zone outdoor airflow zonOutAirRate
shall be calculated as follows:
- If discharge air temperature at the terminal unit is less than or equal to
zone space temperature:
zonOutAirRate = (breZonAre+breZonPop)/disEffCoo. -
If discharge air temperature at the terminal unit is greater than zone space
temperature:
zonOutAirRate = (breZonAre+breZonPop)/disEffHea
- If discharge air temperature at the terminal unit is less than or equal to
zone space temperature:
zonOutAirRate = breZonAre/disEffCoo - If discharge air temperature at the terminal unit is greater than zone
space temperature:
zonOutAirRate = breZonAre/disEffHea
For the single zone system, the required minimum outdoor airflow setpoint
VOutMinSet_flow equals to the zonOutAirRate.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Boolean | have_occSen | Set to true if zones have occupancy sensor | |
| Real | occDen | 0.05 | Default number of person in unit area [1/m2] |
| Real | zonDisEffHea | 0.8 | Zone air distribution effectiveness during heating [1] |
| Real | zonDisEffCoo | 1.0 | Zone air distribution effectiveness during cooling [1] |
| Nominal condition | |||
| Real | VOutPerAre_flow | 3e-4 | Outdoor air rate per unit area [m3/(s.m2)] |
| Real | VOutPerPer_flow | 2.5e-3 | Outdoor air rate per person [m3/s] |
| Real | AFlo | Floor area [m2] | |
| Advanced | |||
| Real | uLow | -0.5 | If zone space temperature minus supply air temperature is less than uLow, then it should use heating supply air distribution effectiveness [K] |
| Real | uHigh | 0.5 | If zone space temperature minus supply air temperature is more than uHig, then it should use cooling supply air distribution effectiveness [K] |
Connectors
| Type | Name | Description |
|---|---|---|
| input RealInput | nOcc | Number of occupants [1] |
| input RealInput | TZon | Measured zone air temperature [K] |
| input RealInput | TDis | Measured discharge air temperature [K] |
| input IntegerInput | uOpeMod | AHU operation mode status signal |
| input BooleanInput | uSupFan | Supply fan status, true if on, false if off |
| input BooleanInput | uWin | Window status, true if open, false if closed |
| output RealOutput | VOutMinSet_flow | Effective minimum outdoor airflow setpoint [m3/s] |
Modelica definition
block OutsideAirFlow
"Output the minimum outdoor airflow rate setpoint for systems with a single zone"
parameter Real VOutPerAre_flow(
final unit="m3/(s.m2)") = 3e-4
"Outdoor air rate per unit area";
parameter Real VOutPerPer_flow(
final unit="m3/s",
final quantity="VolumeFlowRate")= 2.5e-3
"Outdoor air rate per person";
parameter Real AFlo(
final unit="m2",
final quantity="Area") "Floor area";
parameter Boolean have_occSen
"Set to true if zones have occupancy sensor";
parameter Real occDen(final unit="1/m2") = 0.05
"Default number of person in unit area";
parameter Real zonDisEffHea(final unit="1") = 0.8
"Zone air distribution effectiveness during heating";
parameter Real zonDisEffCoo(final unit="1") = 1.0
"Zone air distribution effectiveness during cooling";
parameter Real uLow(
final unit="K",
final displayUnit="K",
final quantity="TemperatureDifference") = -0.5
"If zone space temperature minus supply air temperature is less than uLow,
then it should use heating supply air distribution effectiveness";
parameter Real uHigh(
final unit="K",
final displayUnit="K",
final quantity="TemperatureDifference") = 0.5
"If zone space temperature minus supply air temperature is more than uHig,
then it should use cooling supply air distribution effectiveness";
Buildings.Controls.OBC.CDL.Interfaces.RealInput nOcc(final unit="1")
if have_occSen "Number of occupants";
Buildings.Controls.OBC.CDL.Interfaces.RealInput TZon(
final unit="K",
final displayUnit="degC",
final quantity="ThermodynamicTemperature") "Measured zone air temperature";
Buildings.Controls.OBC.CDL.Interfaces.RealInput TDis(
final unit="K",
final displayUnit="degC",
final quantity="ThermodynamicTemperature") "Measured discharge air temperature";
Buildings.Controls.OBC.CDL.Interfaces.IntegerInput uOpeMod
"AHU operation mode status signal";
Buildings.Controls.OBC.CDL.Interfaces.BooleanInput uSupFan
"Supply fan status, true if on, false if off";
Buildings.Controls.OBC.CDL.Interfaces.BooleanInput uWin
"Window status, true if open, false if closed";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput VOutMinSet_flow(
min=0,
final unit="m3/s",
final quantity="VolumeFlowRate") "Effective minimum outdoor airflow setpoint";
protected
Buildings.Controls.OBC.CDL.Continuous.Add breZon "Breathing zone airflow";
Buildings.Controls.OBC.CDL.Continuous.Subtract sub2
"Zone space temperature minus supply air temperature";
Buildings.Controls.OBC.CDL.Continuous.MultiplyByParameter gai(
final k=VOutPerPer_flow) if have_occSen "Outdoor airflow rate per person";
Buildings.Controls.OBC.CDL.Continuous.Switch swi
"Switch for enabling occupancy sensor input";
Buildings.Controls.OBC.CDL.Continuous.Switch swi1
"Switch between cooling or heating distribution effectiveness";
Buildings.Controls.OBC.CDL.Continuous.Divide zonOutAirRate
"Required zone outdoor airflow rate";
Buildings.Controls.OBC.CDL.Continuous.Switch swi2
"If window is open or it is not in occupied mode, the required outdoor
airflow rate should be zero";
Buildings.Controls.OBC.CDL.Continuous.Switch swi3
"If supply fan is off, then outdoor airflow rate should be zero.";
Buildings.Controls.OBC.CDL.Continuous.Hysteresis hys(
final uLow=uLow,
final uHigh=uHigh,
final pre_y_start=true)
"Check if cooling or heating air distribution effectiveness should be applied, with 1 degC deadband";
Buildings.Controls.OBC.CDL.Logical.Sources.Constant occSen(
final k=have_occSen)
"Boolean constant to indicate if there is occupancy sensor";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant zerOutAir(
final k=0)
"Zero required outdoor airflow rate when window open or zone is not in occupied mode";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant disEffHea(
final k=zonDisEffHea)
"Zone distribution effectiveness during heating";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant disEffCoo(
final k=zonDisEffCoo)
"Zone distribution effectiveness for cooling";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant breZonAre(
final k=VOutPerAre_flow*AFlo)
"Area component of the breathing zone outdoor airflow";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant breZonPop(
final k=VOutPerPer_flow*AFlo*occDen)
"Population component of the breathing zone outdoor airflow";
Buildings.Controls.OBC.CDL.Integers.Equal intEqu1 "Check if operation mode is occupied";
Buildings.Controls.OBC.CDL.Integers.Sources.Constant occMod(
final k=Buildings.Controls.OBC.ASHRAE.G36_PR1.Types.OperationModes.occupied)
"Occupied mode index";
Buildings.Controls.OBC.CDL.Logical.And and1 "Logical and";
Buildings.Controls.OBC.CDL.Logical.Not not1 "Logical not";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant zerOcc(final k=0)
if not have_occSen
"Zero occupant when there is no occupancy sensor";
equation
connect(breZonAre.y, breZon.u1);
connect(gai.y, swi.u1);
connect(breZonPop.y, swi.u3);
connect(swi.y, breZon.u2);
connect(disEffCoo.y, swi1.u1);
connect(disEffHea.y, swi1.u3);
connect(breZon.y, zonOutAirRate.u1);
connect(swi1.y, zonOutAirRate.u2);
connect(uWin, swi2.u2);
connect(zerOutAir.y, swi2.u1);
connect(zonOutAirRate.y, swi2.u3);
connect(swi.u2, occSen.y);
connect(nOcc, gai.u);
connect(swi3.y, VOutMinSet_flow);
connect(TZon, sub2.u1);
connect(TDis, sub2.u2);
connect(sub2.y, hys.u);
connect(hys.y, swi1.u2);
connect(swi2.y, swi3.u3);
connect(zerOutAir.y, swi3.u1);
connect(and1.y, not1.u);
connect(not1.y, swi3.u2);
connect(uSupFan, and1.u1);
connect(intEqu1.y, and1.u2);
connect(uOpeMod, intEqu1.u1);
connect(occMod.y, intEqu1.u2);
connect(swi.u1, zerOcc.y);
end OutsideAirFlow;
Buildings.Controls.OBC.ASHRAE.G36_PR1.AHUs.SingleZone.VAV.SetPoints.Supply
Supply air set point for single zone VAV system
Information
Block that outputs the set points for the supply air temperature for cooling, heating and economizer control, and the fan speed for a single zone VAV system.
For the temperature set points, the
parameters are the maximum supply air temperature TSupSetMax,
and the minimum supply air temperature for cooling TSupSetMin.
The deadband temperature is equal to the
average set point for the zone temperature
for heating and cooling, as obtained from the input TZonSet,
constraint to be within 21°C (≈70 F) and
24°C (≈75 F).
The setpoints are computed as shown in the figure below.
Note that the setpoint for the supply air temperature for heating
and for economizer control is the same, and this setpoint is
lower than TSupSetMin when the heating loop signal
is zero and the economizer is in cooling mode, as shown in the figure.
For the fan speed set point, the
parameters are the maximu fan speed at heating yHeaMax,
the minimum fan speed yMin and
the maximum fan speed for cooling yCooMax.
For a cooling control signal of uCoo > 0.25,
the speed is faster increased the larger the difference is between
the zone temperature minus outdoor temperature TZon-TOut.
The figure below shows the sequence.
The output TSupCoo is to be used to control the cooling coil,
and the output
TSupHeaEco is to be used to control the heating coil and the
economizer dampers.
Note that the inputs uHea and uCoo must be computed
based on the same temperature sensors and control loops.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Temperatures | |||
| Real | TSupSetMax | Maximum supply air temperature for heating [K] | |
| Real | TSupSetMin | Minimum supply air temperature for cooling [K] | |
| Speed | |||
| Real | yHeaMax | Maximum fan speed for heating [1] | |
| Real | yMin | Minimum fan speed [1] | |
| Real | yCooMax | 1 | Maximum fan speed for cooling [1] |
Connectors
| Type | Name | Description |
|---|---|---|
| input RealInput | uHea | Heating control signal [1] |
| input RealInput | uCoo | Cooling control signal [1] |
| input RealInput | TZonSet | Average of heating and cooling setpoints for zone temperature [K] |
| input RealInput | TZon | Zone temperature [K] |
| input RealInput | TOut | Outdoor air temperature [K] |
| output RealOutput | TSupHeaEco | Temperature setpoint for heating coil and for economizer [K] |
| output RealOutput | TSupCoo | Cooling supply air temperature setpoint [K] |
| output RealOutput | y | Fan speed [1] |
| input BooleanInput | uFan | Supply fan status |
Modelica definition
block Supply "Supply air set point for single zone VAV system"
parameter Real TSupSetMax(
final unit="K",
final displayUnit="degC",
final quantity="ThermodynamicTemperature")
"Maximum supply air temperature for heating";
parameter Real TSupSetMin(
final unit="K",
final displayUnit="degC",
final quantity="ThermodynamicTemperature")
"Minimum supply air temperature for cooling";
parameter Real yHeaMax(min=0, max=1, unit="1")
"Maximum fan speed for heating";
parameter Real yMin(min=0, max=1, unit="1")
"Minimum fan speed";
parameter Real yCooMax(min=0, max=1, unit="1") = 1
"Maximum fan speed for cooling";
Buildings.Controls.OBC.CDL.Interfaces.RealInput uHea(min=0, max=1, unit="1")
"Heating control signal";
Buildings.Controls.OBC.CDL.Interfaces.RealInput uCoo(min=0, max=1, unit="1")
"Cooling control signal";
Buildings.Controls.OBC.CDL.Interfaces.RealInput TZonSet(unit="K", displayUnit="degC")
"Average of heating and cooling setpoints for zone temperature";
Buildings.Controls.OBC.CDL.Interfaces.RealInput TZon(unit="K", displayUnit="degC")
"Zone temperature";
Buildings.Controls.OBC.CDL.Interfaces.RealInput TOut(unit="K", displayUnit="degC")
"Outdoor air temperature";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput TSupHeaEco(unit="K", displayUnit="degC")
"Temperature setpoint for heating coil and for economizer";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput TSupCoo(unit="K", displayUnit="degC")
"Cooling supply air temperature setpoint";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput y(min=0, max=1, unit="1") "Fan speed";
Buildings.Controls.OBC.CDL.Interfaces.BooleanInput uFan "Supply fan status";
Buildings.Controls.OBC.CDL.Continuous.Switch switch "Switch to assign control signal";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant fanOff(k=0) "Fan off status";
Buildings.Controls.OBC.CDL.Continuous.Min yFanHeaCoo "Fan speed due to heating or cooling";
protected
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant one(final k=1) "Maximum fan speed";
Buildings.Controls.OBC.CDL.Continuous.Line TSetCooHig
"Table to compute the setpoint for cooling for uCoo = 0...1";
Buildings.Controls.OBC.CDL.Continuous.Line offSetTSetHea
"Table to compute the setpoint offset for heating for uCoo = 0...1";
Buildings.Controls.OBC.CDL.Continuous.Add addTHe
"Adder for heating setpoint calculation";
Buildings.Controls.OBC.CDL.Continuous.Line offSetTSetCoo
"Table to compute the setpoint offset for cooling for uHea = 0...1";
Buildings.Controls.OBC.CDL.Continuous.Add addTSupCoo
"Adder for cooling setpoint calculation";
Buildings.Controls.OBC.CDL.Continuous.Subtract dT
"Difference zone minus outdoor temperature";
Buildings.Controls.OBC.CDL.Continuous.MultiplyByParameter gai1(
final k=(yMin - yCooMax)/(0.56 - 5.6))
"Gain factor";
Buildings.Controls.OBC.CDL.Continuous.AddParameter yMed(
final p=yCooMax - (yMin - yCooMax)/(0.56 - 5.6)*5.6)
"Fan speed at medium cooling load";
Buildings.Controls.OBC.CDL.Continuous.Limiter yMedLim(
final uMax=yCooMax,
final uMin=yMin) "Limiter for yMed";
Buildings.Controls.OBC.CDL.Continuous.Limiter TDea(
final uMax=24 + 273.15,
final uMin=21 + 273.15)
"Limiter that outputs the dead band value for the supply air temperature";
Buildings.Controls.OBC.CDL.Continuous.Line TSetHeaHig
"Block to compute the setpoint for heating for uHea = 0...1";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant con0(
final k=0) "Contant that outputs zero";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant con25(
final k=0.25) "Contant that outputs 0.25";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant con05(
final k=0.5) "Contant that outputs 0.5";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant con75(
final k=0.75) "Contant that outputs 0.75";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant conTSupSetMax(
final k=TSupSetMax) "Constant that outputs TSupSetMax";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant conTSupSetMin(
final k=TSupSetMin) "Constant that outputs TSupSetMin";
Buildings.Controls.OBC.CDL.Continuous.Subtract TDeaTSupSetMin
"Outputs TDea-TSupSetMin";
Buildings.Controls.OBC.CDL.Continuous.MultiplyByParameter gai(
final k=-1)
"Gain factor";
Buildings.Controls.OBC.CDL.Continuous.AddParameter addTDea(
final p=-1.1)
"Adds constant offset";
Buildings.Controls.OBC.CDL.Continuous.Subtract TSupSetMaxTDea
"Outputs TSupSetMax-TDea";
Buildings.Controls.OBC.CDL.Continuous.Line yHea "Fan speed for heating";
Buildings.Controls.OBC.CDL.Continuous.Line lin050(
final limitBelow=true,
final limitAbove=true)
"Linear increase in control signal for 0 < yCoo < 0.75";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant con025(
final k=0.25) "Constant signal";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant con1(
final k=0.5) "Constant signal";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant con2(
final k=1) "Constant signal";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant con3(
final k=0) "Constant signal";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant con4(
final k=yCooMax - yMin) "Constant signal";
Buildings.Controls.OBC.CDL.Continuous.Subtract dY075
"Change in control signal above yMedLim for y > 0.75";
Buildings.Controls.OBC.CDL.Continuous.Line lin075(
final limitBelow=true,
final limitAbove=true)
"Linear increase in control signal for 0.75 < yCoo";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant con5(
final k=0.75) "Constant signal";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant con6(
final k=0) "Constant signal";
Buildings.Controls.OBC.CDL.Continuous.AddParameter yOffSet(
final p=-yMin)
"Subtract yMin so that all control signals can be added";
Buildings.Controls.OBC.CDL.Continuous.Add addHeaCoo
"Add heating control signal and offset due to cooling";
Buildings.Controls.OBC.CDL.Continuous.Add offCoo
"Offset of control signal (relative to heating signal) for cooling";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant con7(final k=0.5)
"Contant that outputs 0.5";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant minSpe(final k=yMin)
"Contant that outputs minimum fan speed";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant conOne(final k=1)
"Contant that outputs 1";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant maxHeaSpe(final k=yHeaMax)
"Contant that outputs maximum fan speed for heating";
equation
connect(offSetTSetHea.u, uCoo);
connect(offSetTSetHea.y, addTHe.u2);
connect(addTHe.y, TSupHeaEco);
connect(TSetCooHig.y, addTSupCoo.u1);
connect(offSetTSetCoo.y, addTSupCoo.u2);
connect(TSetCooHig.u, uCoo);
connect(offSetTSetCoo.u, uHea);
connect(addTSupCoo.y, TSupCoo);
connect(dT.u1, TZon);
connect(dT.u2, TOut);
connect(yMedLim.u, yMed.y);
connect(TDea.u, TZonSet);
connect(TDea.y, TSetHeaHig.f1);
connect(con05.y, TSetHeaHig.x2);
connect(conTSupSetMax.y, TSetHeaHig.f2);
connect(uHea, TSetHeaHig.u);
connect(TSetHeaHig.y, addTHe.u1);
connect(con0.y, offSetTSetHea.x1);
connect(con25.y, offSetTSetHea.x2);
connect(con0.y, offSetTSetHea.f1);
connect(TDea.y, TDeaTSupSetMin.u1);
connect(conTSupSetMin.y, TDeaTSupSetMin.u2);
connect(addTDea.y, offSetTSetHea.f2);
connect(TSetCooHig.x1, con05.y);
connect(TSetCooHig.f1, TDea.y);
connect(TSetCooHig.x2, con75.y);
connect(TSetCooHig.f2, conTSupSetMin.y);
connect(offSetTSetCoo.f1, con0.y);
connect(offSetTSetCoo.x1, con0.y);
connect(offSetTSetCoo.x2, con05.y);
connect(TSupSetMaxTDea.u1, conTSupSetMax.y);
connect(TDea.y, TSupSetMaxTDea.u2);
connect(TSupSetMaxTDea.y, offSetTSetCoo.f2);
connect(uCoo, lin050.u);
connect(dY075.u1, con4.y);
connect(lin075.x2, con2.y);
connect(lin075.x1, con5.y);
connect(uCoo, lin075.u);
connect(yMedLim.y, yOffSet.u);
connect(dY075.u2, yOffSet.y);
connect(offCoo.u1, lin050.y);
connect(offCoo.u2, lin075.y);
connect(offCoo.y, addHeaCoo.u2);
connect(lin050.x2, con1.y);
connect(con025.y, lin050.x1);
connect(lin050.f2, yOffSet.y);
connect(con3.y, lin050.f1);
connect(dY075.y, lin075.f2);
connect(con6.y, lin075.f1);
connect(TSetHeaHig.x1, con0.y);
connect(con7.y, yHea.x1);
connect(minSpe.y, yHea.f1);
connect(uHea, yHea.u);
connect(conOne.y, yHea.x2);
connect(maxHeaSpe.y, yHea.f2);
connect(yHea.y, addHeaCoo.u1);
connect(uFan, switch.u2);
connect(fanOff.y, switch.u3);
connect(switch.y, y);
connect(one.y, yFanHeaCoo.u1);
connect(addHeaCoo.y, yFanHeaCoo.u2);
connect(yFanHeaCoo.y, switch.u1);
connect(TDeaTSupSetMin.y, gai.u);
connect(gai.y, addTDea.u);
connect(dT.y, gai1.u);
connect(gai1.y, yMed.u);
end Supply;