Buildings.Controls.OBC.ASHRAE.G36.TerminalUnits.DualDuctMixConDischargeSensor.Subsequences
Package of subsequences for dual-duct terminal unit using mixing control with discharge flow sensor
Information
This package contains subsequences for dual-duct terminal unit using mixing control with discharge flow sensor. They are created according to Section 5.13 of ASHRAE Guideline 36, May 2020.
Package Content
| Name | Description |
|---|---|
 ActiveAirFlow
|
Output the active airflow setpoint for dual-duct terminal unit using mixing control with discharge flow sensor |
 Alarms
|
Generate alarms of dual-duct terminal unit using mixing control with discharge flow sensor |
 Dampers
|
Output signals for controlling dampers of dual-duct terminal unit using mixing control with discharge flow sensor |
 Overrides
|
Software switches to override setpoints |
 SystemRequests
|
Output system requests for dual-duct unit using mixing control with discharge flow sensor |
 Validation
|
Collection of validation models |
Buildings.Controls.OBC.ASHRAE.G36.TerminalUnits.DualDuctMixConDischargeSensor.Subsequences.ActiveAirFlow
Output the active airflow setpoint for dual-duct terminal unit using mixing control with discharge flow sensor
Information
This sequence sets the active cooling and heating maximum and the active minimum setpoints for dual-duct terminal unit using mixing control with discharge flow sensor. The implementation is according to the Section 5.13.4 of ASHRAE Guideline 36, May 2020.
The setpoints shall vary depending on the mode of the zone group.
| Setpoint | Occupied | Cooldown | Setup | Warm-up | Setback | Unoccupied |
|---|---|---|---|---|---|---|
Cooling maximum (VActCooMax_flow) | VCooMax_flow |
VCooMax_flow | VCooMax_flow |
0 | 0 | 0 |
Minimum (VActMin_flow) | VOccMin_flow | 0 | 0 | 0 | 0 | 0 |
Heating maximum (VActHeaMax_flow) | VHeaMax_flow |
0 | 0 | VHeaMax_flow | VHeaMax_flow |
0 |
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Real | VCooMax_flow | Design zone cooling maximum airflow rate [m3/s] | |
| Real | VHeaMax_flow | Design zone heating maximum airflow rate [m3/s] |
Connectors
| Type | Name | Description |
|---|---|---|
| input RealInput | VOccMin_flow | Occupied minimum airflow setpoint [m3/s] |
| input IntegerInput | uOpeMod | Zone operation mode |
| output RealOutput | VActCooMax_flow | Active cooling maximum airflow setpoint [m3/s] |
| output RealOutput | VActMin_flow | Active minimum airflow setpoint [m3/s] |
| output RealOutput | VActHeaMax_flow | Active heating maximum airflow setpoint [m3/s] |
Modelica definition
block ActiveAirFlow
"Output the active airflow setpoint for dual-duct terminal unit using mixing control with discharge flow sensor"
parameter Real VCooMax_flow(
final quantity="VolumeFlowRate",
final unit="m3/s")
"Design zone cooling maximum airflow rate";
parameter Real VHeaMax_flow(
final quantity="VolumeFlowRate",
final unit="m3/s")
"Design zone heating maximum airflow rate";
Buildings.Controls.OBC.CDL.Interfaces.RealInput VOccMin_flow(
final unit="m3/s",
final quantity="VolumeFlowRate")
"Occupied minimum airflow setpoint";
Buildings.Controls.OBC.CDL.Interfaces.IntegerInput uOpeMod
"Zone operation mode";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput VActCooMax_flow(
final min=0,
final unit="m3/s",
final quantity="VolumeFlowRate")
"Active cooling maximum airflow setpoint";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput VActMin_flow(
final min=0,
final unit="m3/s",
final quantity="VolumeFlowRate")
"Active minimum airflow setpoint";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput VActHeaMax_flow(
final min=0,
final unit="m3/s",
final quantity="VolumeFlowRate")
"Active heating maximum airflow setpoint";
protected
Buildings.Controls.OBC.CDL.Integers.Sources.Constant occMod(
final k=Buildings.Controls.OBC.ASHRAE.G36.Types.OperationModes.occupied)
"Occupied mode";
Buildings.Controls.OBC.CDL.Integers.Sources.Constant cooDowMod(
final k=Buildings.Controls.OBC.ASHRAE.G36.Types.OperationModes.coolDown)
"Cool down mode";
Buildings.Controls.OBC.CDL.Integers.Sources.Constant setUpMod(
final k=Buildings.Controls.OBC.ASHRAE.G36.Types.OperationModes.setUp)
"Setup mode";
Buildings.Controls.OBC.CDL.Logical.Or3 or3
"Check if it is in occupied, cooldown, or setup mode";
Buildings.Controls.OBC.CDL.Conversions.BooleanToReal actCooMax(
final realTrue=VCooMax_flow)
"Active cooling maximum flow";
Buildings.Controls.OBC.CDL.Conversions.BooleanToReal occModInd(
final realTrue=1)
"If in occupied mode, output 1";
Buildings.Controls.OBC.CDL.Continuous.Multiply pro
"Active cooling minimum, minimum airflow setpoint";
Buildings.Controls.OBC.CDL.Conversions.BooleanToReal heaMaxFlo(
final realTrue=VHeaMax_flow)
"Heating maximum flow when input is true";
Buildings.Controls.OBC.CDL.Integers.Sources.Constant setBacMod(
final k=Buildings.Controls.OBC.ASHRAE.G36.Types.OperationModes.setBack)
"Setback mode";
Buildings.Controls.OBC.CDL.Integers.Sources.Constant warUpMod(
final k=Buildings.Controls.OBC.ASHRAE.G36.Types.OperationModes.warmUp)
"Warm up mode";
Buildings.Controls.OBC.CDL.Integers.Equal ifOcc
"Check if current operation mode is occupied mode";
Buildings.Controls.OBC.CDL.Integers.Equal ifCooDow
"Check if current operation mode is cooldown mode";
Buildings.Controls.OBC.CDL.Integers.Equal ifSetUp
"Check if current operation mode is setup mode";
Buildings.Controls.OBC.CDL.Integers.Equal ifWarUp
"Check if current operation mode is warm-up mode";
Buildings.Controls.OBC.CDL.Integers.Equal ifSetBac
"Check if current operation mode is setback mode";
Buildings.Controls.OBC.CDL.Logical.Or3 or1
"Check if it is in occupied, warm-up, or setback mode";
equation
connect(occMod.y, ifOcc.u1);
connect(cooDowMod.y, ifCooDow.u1);
connect(setUpMod.y, ifSetUp.u1);
connect(warUpMod.y, ifWarUp.u1);
connect(uOpeMod, ifOcc.u2);
connect(uOpeMod, ifCooDow.u2);
connect(uOpeMod, ifSetUp.u2);
connect(uOpeMod, ifWarUp.u2);
connect(uOpeMod, ifSetBac.u2);
connect(setBacMod.y, ifSetBac.u1);
connect(ifOcc.y, or3.u1);
connect(ifCooDow.y, or3.u2);
connect(ifSetUp.y, or3.u3);
connect(or3.y, actCooMax.u);
connect(ifOcc.y, occModInd.u);
connect(VOccMin_flow, pro.u2);
connect(occModInd.y, pro.u1);
connect(actCooMax.y, VActCooMax_flow);
connect(pro.y, VActMin_flow);
connect(ifOcc.y, or1.u1);
connect(ifWarUp.y, or1.u2);
connect(ifSetBac.y, or1.u3);
connect(or1.y, heaMaxFlo.u);
connect(heaMaxFlo.y, VActHeaMax_flow);
end ActiveAirFlow;
Buildings.Controls.OBC.ASHRAE.G36.TerminalUnits.DualDuctMixConDischargeSensor.Subsequences.Alarms
Generate alarms of dual-duct terminal unit using mixing control with discharge flow sensor
Information
This block outputs alarms of dual-duct terminal unit using mixing control with discharge flow sensor. The implementation is according to the Section 5.13.6 of ASHRAE Guideline 36, May 2020.
Low airflow
-
If the measured airflow
VDis_flowis less than 70% of setpointVActSet_flowfor 5 minutes (lowFloTim) while the setpoint is greater than zero, generate a Level 3 alarm. -
If the measured airflow
VDis_flowis less than 50% of setpointVActSet_flowfor 5 minutes (lowFloTim) while the setpoint is greater than zero, generate a Level 2 alarm. -
If a zone has an importance multiplier (
staPreMul) of 0 for its static pressure reset Trim-Respond control loop, low airflow alarms shall be suppressed for that zone.
Airflow sensor calibration
-
If the cooling and heating fans serving the zone have been OFF (
u1CooFan=falseandu1HeaFan=false) for 10 minutes (fanOffTim), and the discharge airflow sensor readingVDis_flowis above 10% of the cooling maximum airflow setpointVCooMax_flow, generate a Level 3 alarm.
Leaking damper
-
If the cooling and heating damper position (
uCooDamanduHeaDam) are 0% and airflow sensor readingVDis_flowis above 10% of the cooling maximum airflow setpointVCooMax_flowfor 10 minutes (leaFloTim) while the fan serving the zone is proven on (u1CooFan=trueoru1HeaFan=true), generate a Level 4 alarm.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Real | staPreMul | Importance multiplier for the zone static pressure reset control loop | |
| Real | VCooMax_flow | Design zone cooling maximum airflow rate [m3/s] | |
| Real | lowFloTim | 300 | Threshold time to check low flow rate [s] |
| Real | fanOffTim | 600 | Threshold time to check fan off [s] |
| Real | leaFloTim | 600 | Threshold time to check damper leaking airflow [s] |
| Advanced | |||
| Real | floHys | 0.05 | Near zero flow rate, below which the flow rate or difference will be seen as zero [m3/s] |
| Real | damPosHys | 0.05 | Near zero damper position, below which the damper will be seen as closed [1] |
Connectors
| Type | Name | Description |
|---|---|---|
| input RealInput | VDis_flow | Measured discharge airflow rate [m3/s] |
| input RealInput | VActSet_flow | Active airflow setpoint [m3/s] |
| input BooleanInput | u1CooFan | Cooling air handler supply fan status |
| input BooleanInput | u1HeaFan | Heating air handler supply fan status |
| input RealInput | uCooDam | Cooling damper position setpoint [1] |
| input RealInput | uHeaDam | Heating damper position setpoint [1] |
| output IntegerOutput | yLowFloAla | Low airflow alarms |
| output IntegerOutput | yFloSenAla | Airflow sensor calibration alarm |
| output IntegerOutput | yLeaDamAla | Leaking dampers alarm, could be heating or cooling damper |
Modelica definition
block Alarms
"Generate alarms of dual-duct terminal unit using mixing control with discharge flow sensor"
parameter Real staPreMul
"Importance multiplier for the zone static pressure reset control loop";
parameter Real VCooMax_flow(
final quantity="VolumeFlowRate",
final unit="m3/s")
"Design zone cooling maximum airflow rate";
parameter Real lowFloTim(
final unit="s",
final quantity="Time")=300
"Threshold time to check low flow rate";
parameter Real fanOffTim(
final unit="s",
final quantity="Time")=600
"Threshold time to check fan off";
parameter Real leaFloTim(
final unit="s",
final quantity="Time")=600
"Threshold time to check damper leaking airflow";
parameter Real floHys(
final quantity="VolumeFlowRate",
final unit="m3/s")=0.05
"Near zero flow rate, below which the flow rate or difference will be seen as zero";
parameter Real damPosHys(
final unit="1")=0.05
"Near zero damper position, below which the damper will be seen as closed";
Buildings.Controls.OBC.CDL.Interfaces.RealInput VDis_flow(
final min=0,
final unit="m3/s",
final quantity="VolumeFlowRate") "Measured discharge airflow rate";
Buildings.Controls.OBC.CDL.Interfaces.RealInput VActSet_flow(
final min=0,
final unit="m3/s",
final quantity="VolumeFlowRate") "Active airflow setpoint";
Buildings.Controls.OBC.CDL.Interfaces.BooleanInput u1CooFan
"Cooling air handler supply fan status";
Buildings.Controls.OBC.CDL.Interfaces.BooleanInput u1HeaFan
"Heating air handler supply fan status";
Buildings.Controls.OBC.CDL.Interfaces.RealInput uCooDam(
final min=0,
final unit="1")
"Cooling damper position setpoint";
Buildings.Controls.OBC.CDL.Interfaces.RealInput uHeaDam(
final min=0,
final unit="1")
"Heating damper position setpoint";
Buildings.Controls.OBC.CDL.Interfaces.IntegerOutput yLowFloAla
"Low airflow alarms";
Buildings.Controls.OBC.CDL.Interfaces.IntegerOutput yFloSenAla
"Airflow sensor calibration alarm";
Buildings.Controls.OBC.CDL.Interfaces.IntegerOutput yLeaDamAla
"Leaking dampers alarm, could be heating or cooling damper";
Buildings.Controls.OBC.CDL.Continuous.MultiplyByParameter gai(
final k=0.5)
"Percentage of the setpoint";
Buildings.Controls.OBC.CDL.Continuous.Less les(
final h=floHys)
"Check if measured airflow is less than threshold";
Buildings.Controls.OBC.CDL.Logical.TrueDelay truDel(
final delayTime=lowFloTim)
"Check if the measured airflow has been less than threshold value for threshold time";
Buildings.Controls.OBC.CDL.Continuous.GreaterThreshold greThr(
final h=floHys)
"Check if setpoint airflow is greater than zero";
Buildings.Controls.OBC.CDL.Continuous.Greater gre(
final h=floHys)
"Check if measured airflow is less than threshold";
Buildings.Controls.OBC.CDL.Continuous.MultiplyByParameter gai1(
final k=0.7)
"Percentage of the setpoint";
Buildings.Controls.OBC.CDL.Logical.TrueDelay truDel1(
final delayTime=lowFloTim)
"Check if the measured airflow has been less than threshold value for threshold time";
Buildings.Controls.OBC.CDL.Logical.And and2
"Measured airflow has been less than threshold value for sufficient time";
Buildings.Controls.OBC.CDL.Logical.And and1
"Measured airflow has been less than threshold value for sufficient time";
Buildings.Controls.OBC.CDL.Integers.Switch lowFloAla
"Low airflow alarm";
Buildings.Controls.OBC.CDL.Integers.Sources.Constant conInt(
final k=2)
"Level 2 alarm";
Buildings.Controls.OBC.CDL.Conversions.BooleanToInteger booToInt(
final integerTrue=3)
"Convert boolean true to level 3 alarm";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant conInt1(
final k=staPreMul)
"Importance multiplier for zone static pressure reset";
Buildings.Controls.OBC.CDL.Continuous.GreaterThreshold greThr1
"Check if the multiplier is greater than zero";
Buildings.Controls.OBC.CDL.Conversions.BooleanToInteger booToInt1
"Suppress the alarm when multiplier is zero";
Buildings.Controls.OBC.CDL.Integers.Multiply proInt
"Low flow alarms";
Buildings.Controls.OBC.CDL.Logical.And and3
"Logical and";
Buildings.Controls.OBC.CDL.Logical.Not not1
"Logical not";
Buildings.Controls.OBC.CDL.Utilities.Assert assMes(
final message="Warning: airflow is less than 50% of the setpoint.")
"Level 2 low airflow alarm";
Buildings.Controls.OBC.CDL.Logical.And and4
"Logical and";
Buildings.Controls.OBC.CDL.Logical.Not not2
"Logical not";
Buildings.Controls.OBC.CDL.Utilities.Assert assMes1(
final message="Warning: airflow is less than 70% of the setpoint.")
"Level 3 low airflow alarm";
Buildings.Controls.OBC.CDL.Continuous.LessThreshold cloDam(
final t=damPosHys,
final h=0.5*damPosHys) "Check if damper position is near zero";
Buildings.Controls.OBC.CDL.Continuous.LessThreshold cloDam1(
final t=damPosHys,
final h=0.5*damPosHys)
"Check if damper position is near zero";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant cooMaxFlo1(
final k=VCooMax_flow)
"Cooling maximum airflow setpoint";
Buildings.Controls.OBC.CDL.Continuous.MultiplyByParameter gai4(
final k=0.1)
"Percentage of the setpoint";
Buildings.Controls.OBC.CDL.Continuous.Greater gre3(
final h=floHys)
"Check if measured airflow is greater than threshold";
Buildings.Controls.OBC.CDL.Logical.And and7
"Logical and";
Buildings.Controls.OBC.CDL.Logical.Not not9
"Logical not";
Buildings.Controls.OBC.CDL.Utilities.Assert assMes6(
final message="Warning: airflow sensor should be calibrated.")
"Level 3 airflow sensor alarm";
Buildings.Controls.OBC.CDL.Conversions.BooleanToInteger booToInt6(
final integerTrue=3)
"Convert boolean true to level 3 alarm";
Buildings.Controls.OBC.CDL.Logical.Or or2
"Check if there is any supply fan proven on";
Buildings.Controls.OBC.CDL.Logical.TrueDelay truDel6(
final delayTime=fanOffTim)
"Check if the supply fan has been OFF more than threshold time";
Buildings.Controls.OBC.CDL.Logical.Not not10
"Logical not";
Buildings.Controls.OBC.CDL.Logical.TrueDelay truDel7(
final delayTime=leaFloTim)
"Check if the air flow is above threshold by more than threshold time";
Buildings.Controls.OBC.CDL.Logical.And3 leaDamAla2
"Check if generating leak damper alarms";
Buildings.Controls.OBC.CDL.Logical.And cloBotDam
"Both heating and cooling dampers are closed";
Buildings.Controls.OBC.CDL.Logical.Not not11
"Logical not";
Buildings.Controls.OBC.CDL.Utilities.Assert assMes7(
final message="Warning: the cold-duct or hot-dcut damper is leaking.")
"Level 4 leaking damper alarm";
Buildings.Controls.OBC.CDL.Conversions.BooleanToInteger booToInt7(
final integerTrue=4)
"Convert boolean true to level 4 alarm";
equation
connect(VActSet_flow, gai.u);
connect(VDis_flow, les.u1);
connect(gai.y, les.u2);
connect(les.y, truDel.u);
connect(VActSet_flow, greThr.u);
connect(VActSet_flow, gai1.u);
connect(VDis_flow, gre.u2);
connect(gai1.y, gre.u1);
connect(gre.y, truDel1.u);
connect(truDel.y, and2.u1);
connect(greThr.y, and2.u2);
connect(greThr.y, and1.u1);
connect(truDel1.y, and1.u2);
connect(and2.y, lowFloAla.u2);
connect(conInt.y, lowFloAla.u1);
connect(and1.y, booToInt.u);
connect(booToInt.y, lowFloAla.u3);
connect(conInt1.y, greThr1.u);
connect(greThr1.y, booToInt1.u);
connect(lowFloAla.y, proInt.u1);
connect(booToInt1.y, proInt.u2);
connect(not1.y, assMes.u);
connect(and3.y, not1.u);
connect(and2.y, and3.u1);
connect(greThr1.y, and3.u2);
connect(and1.y, and4.u1);
connect(greThr1.y, and4.u2);
connect(and4.y, not2.u);
connect(not2.y, assMes1.u);
connect(proInt.y, yLowFloAla);
connect(uCooDam, cloDam.u);
connect(uHeaDam, cloDam1.u);
connect(and7.y,not9. u);
connect(and7.y,booToInt6. u);
connect(VDis_flow, gre3.u1);
connect(gre3.y, and7.u1);
connect(u1CooFan, or2.u1);
connect(u1HeaFan, or2.u2);
connect(or2.y, not10.u);
connect(not10.y, truDel6.u);
connect(truDel6.y, and7.u2);
connect(not9.y, assMes6.u);
connect(booToInt6.y, yFloSenAla);
connect(gai4.y, gre3.u2);
connect(gre3.y, truDel7.u);
connect(truDel7.y, leaDamAla2.u1);
connect(cooMaxFlo1.y, gai4.u);
connect(cloBotDam.y, leaDamAla2.u3);
connect(or2.y, leaDamAla2.u2);
connect(cloDam.y, cloBotDam.u1);
connect(cloDam1.y, cloBotDam.u2);
connect(not11.y, assMes7.u);
connect(leaDamAla2.y, booToInt7.u);
connect(booToInt7.y, yLeaDamAla);
connect(leaDamAla2.y, not11.u);
end Alarms;
Buildings.Controls.OBC.ASHRAE.G36.TerminalUnits.DualDuctMixConDischargeSensor.Subsequences.Dampers
Output signals for controlling dampers of dual-duct terminal unit using mixing control with discharge flow sensor
Information
This sequence sets the dampers for dual-duct terminal unit using mixing control with discharge flow sensor. The implementation is according to Section 5.13.5 of ASHRAE Guideline 36, May 2020. The calculation is done following the steps below.
-
When the zone state is cooling (
uCoo > 0), then the cooling loop outputuCooshall reset the supply airflow setpoint from the minimumVActMin_flowto cooling maximum setpointVActCooMax_flow. The cooling damper shall be modulated by a control loop to maintain the measured aiflowVDis_flowat setpoint. The heating damper shall be closedyHeaDam=0.-
If the cold-deck supply air temperature
TColSupfrom the cooling air handler is greater than room temperatureTZon, cooling supply airflow setpoint shall be no higher than the minimum.
-
If the cold-deck supply air temperature
-
When the zone state is deadband (
uCoo=0anduHea=0), the cooling airflow set pointVColDucDis_flow_Setshall be the minimum set pointVActMin_flow. The cooling damper shall be modulated by a control loop to maintain the measured cooling airflow at set point. The heating damper shall be closed. -
When the zone state is heating (
uHea > 0), then the heating loop outputuHeashall be mapped to the heating damper position. The cooling damper is modulated to maintain measured discharge airflow at the minimum airflow setpointVActMin_flow.-
If the hot-deck supply air temperature
THotSupfrom the heating air handler is less than room temperatureTZon, the heating damper shall be closed. -
Maximum heating airflow shall be limited by a reverse-acting P-only loop whose setpoint
is the heating maximum
VActHeaMax_flowand whose output is maximum heating damper position rangingfrom 0% to 100%.
-
If the hot-deck supply air temperature
-
Overriding above controls:
-
If heating air handler is not proven ON (
u1HeaAHU=false), the heating damper shall be closed (yHeaDam=0). -
If cooling air handler is not proven ON (
u1CooAHU=false), the cooling damper shall be closed (yCooDam=0).
-
If heating air handler is not proven ON (
The sequences of controlling dampers position for dual-duct terminal unit using mixing control with inlet flow sensor are described in the following figure below.
Note that when the zone is in heating state, the wordings in Section 5.13.5.1.c does not specify the flow setpoint. This causes confusion when implementing system request sequences that is specified in Section 5.13.8.4, which requires the flow setpoint. To avoid the confusion, the sequence was then implemented according to the plot above, which is Figure 5.13.5 in Guideline 36.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Boolean | have_preIndDam | true | True: the VAV damper is pressure independent (with built-in flow controller) |
| Real | VCooMax_flow | Design zone cooling maximum airflow rate [m3/s] | |
| Real | VHeaMax_flow | Design zone heating maximum airflow rate [m3/s] | |
| SimpleController | controllerTypeDam | Buildings.Controls.OBC.CDL.T... | Type of controller |
| Real | kDam | 0.5 | Gain of controller for damper control [1] |
| Real | TiDam | 300 | Time constant of integrator block for damper control [s] |
| Real | TdDam | 0.1 | Time constant of derivative block for damper control [s] |
| Real | kHeaMaxDam | 0.5 | Gain of controller for heating maximum damper control [1] |
| Advanced | |||
| Real | dTHys | 0.25 | Temperature difference hysteresis below which the temperature difference will be seen as zero [K] |
| Real | looHys | 0.05 | Loop output hysteresis below which the output will be seen as zero [1] |
Connectors
| Type | Name | Description |
|---|---|---|
| input RealInput | uCoo | Cooling control signal [1] |
| input RealInput | VActCooMax_flow | Active cooling maximum airflow rate [m3/s] |
| input RealInput | TColSup | Cold duct supply air temperature from central air handler [K] |
| input RealInput | VDis_flow | Measured discharge airflow rate airflow rate [m3/s] |
| input BooleanInput | u1CooAHU | Cooling air handler status |
| input RealInput | VActMin_flow | Active minimum airflow rate [m3/s] |
| input RealInput | TZon | Measured zone temperature [K] |
| input RealInput | THotSup | Hot duct supply air temperature from central air handler [K] |
| input RealInput | uHea | Heating control signal [1] |
| input RealInput | VActHeaMax_flow | Active heating maximum airflow rate [m3/s] |
| input BooleanInput | u1HeaAHU | Heating air handler status |
| output RealOutput | VDis_flow_Set | Discharge airflow setpoint [m3/s] |
| output RealOutput | VColDucDis_flow_Set | Cold duct discharge airflow setpoint [m3/s] |
| output RealOutput | yCooDam | Cold duct damper commanded position [1] |
| output RealOutput | yHeaDam | Hot duct damper commanded position [1] |
Modelica definition
block Dampers
"Output signals for controlling dampers of dual-duct terminal unit using mixing control with discharge flow sensor"
parameter Boolean have_preIndDam = true
"True: the VAV damper is pressure independent (with built-in flow controller)";
parameter Real VCooMax_flow(
final quantity="VolumeFlowRate",
final unit="m3/s")
"Design zone cooling maximum airflow rate";
parameter Real VHeaMax_flow(
final quantity="VolumeFlowRate",
final unit="m3/s")
"Design zone heating maximum airflow rate";
parameter Buildings.Controls.OBC.CDL.Types.SimpleController controllerTypeDam=
Buildings.Controls.OBC.CDL.Types.SimpleController.PI
"Type of controller";
parameter Real kDam(final unit="1")=0.5
"Gain of controller for damper control";
parameter Real TiDam(
final unit="s",
final quantity="Time")=300
"Time constant of integrator block for damper control";
parameter Real TdDam(
final unit="s",
final quantity="Time")=0.1
"Time constant of derivative block for damper control";
parameter Real kHeaMaxDam(final unit="1")=0.5
"Gain of controller for heating maximum damper control";
parameter Real dTHys(
final unit="K",
final quantity="TemperatureDifference")=0.25
"Temperature difference hysteresis below which the temperature difference will be seen as zero";
parameter Real looHys(
final unit="1") = 0.05
"Loop output hysteresis below which the output will be seen as zero";
Buildings.Controls.OBC.CDL.Interfaces.RealInput uCoo(
final min=0,
final max=1,
final unit="1")
"Cooling control signal";
Buildings.Controls.OBC.CDL.Interfaces.RealInput VActCooMax_flow(
final min=0,
final unit="m3/s",
final quantity="VolumeFlowRate")
"Active cooling maximum airflow rate";
Buildings.Controls.OBC.CDL.Interfaces.RealInput TColSup(
final unit="K",
final displayUnit="degC",
final quantity="ThermodynamicTemperature")
"Cold duct supply air temperature from central air handler";
Buildings.Controls.OBC.CDL.Interfaces.RealInput VDis_flow(
final min=0,
final unit="m3/s",
final quantity="VolumeFlowRate") if not have_preIndDam
"Measured discharge airflow rate airflow rate";
Buildings.Controls.OBC.CDL.Interfaces.BooleanInput u1CooAHU
"Cooling air handler status";
Buildings.Controls.OBC.CDL.Interfaces.RealInput VActMin_flow(
final min=0,
final unit="m3/s",
final quantity="VolumeFlowRate")
"Active minimum airflow rate";
Buildings.Controls.OBC.CDL.Interfaces.RealInput TZon(
final unit="K",
final displayUnit="degC",
final quantity="ThermodynamicTemperature")
"Measured zone temperature";
Buildings.Controls.OBC.CDL.Interfaces.RealInput THotSup(
final unit="K",
final displayUnit="degC",
final quantity="ThermodynamicTemperature")
"Hot duct supply air temperature from central air handler";
Buildings.Controls.OBC.CDL.Interfaces.RealInput uHea(
final min=0,
final max=1,
final unit="1")
"Heating control signal";
Buildings.Controls.OBC.CDL.Interfaces.RealInput VActHeaMax_flow(
final min=0,
final unit="m3/s",
final quantity="VolumeFlowRate")
"Active heating maximum airflow rate";
Buildings.Controls.OBC.CDL.Interfaces.BooleanInput u1HeaAHU
"Heating air handler status";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput VDis_flow_Set(
final min=0,
final unit="m3/s",
final quantity="VolumeFlowRate")
"Discharge airflow setpoint";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput VColDucDis_flow_Set(
final min=0,
final unit="m3/s",
final quantity="VolumeFlowRate")
"Cold duct discharge airflow setpoint";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput yCooDam(
final min=0,
final max=1,
final unit="1") "Cold duct damper commanded position";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput yHeaDam(
final min=0,
final max=1,
final unit="1") "Hot duct damper commanded position";
Buildings.Controls.OBC.CDL.Logical.And and4 "Logical and";
Buildings.Controls.OBC.CDL.Continuous.Line lin
"Active airflow setpoint for cooling";
Buildings.Controls.OBC.CDL.Continuous.Switch swi
"Output active cold duct airflow setpoint";
Buildings.Controls.OBC.CDL.Continuous.Switch swi5
"Airflow setpoint when it is in cooling state";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant conZer(
final k=0) "Constant zero";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant conOne(
final k=1) "Constant one";
Buildings.Controls.OBC.CDL.Continuous.GreaterThreshold greThr1(
final t=looHys,
final h=0.5*looHys)
"Check if it is cooling state";
Buildings.Controls.OBC.CDL.Continuous.GreaterThreshold greThr(
final t=dTHys,
final h=0.5*dTHys)
"Check if supply air temperature is greater than room temperature";
Buildings.Controls.OBC.CDL.Continuous.Subtract sub2
"Calculate temperature difference between AHU supply air and room ";
Buildings.Controls.OBC.CDL.Logical.Or or2
"Cooing or heating state";
Buildings.Controls.OBC.CDL.Continuous.GreaterThreshold greThr2(
final t=looHys,
final h=0.5*looHys) "Check if it is heating state";
Buildings.Controls.OBC.CDL.Logical.Not not1
"In deadband state";
Buildings.Controls.OBC.CDL.Continuous.Switch swi1
"Active cold duct airflow setpoint when it is in deadband state";
Buildings.Controls.OBC.CDL.Continuous.Subtract sub1
"Calculate temperature difference between AHU supply air and room ";
Buildings.Controls.OBC.CDL.Continuous.GreaterThreshold greThr3(
final t=dTHys,
final h=0.5*dTHys)
"Check if supply air temperature is less than room temperature";
Buildings.Controls.OBC.CDL.Logical.And and1
"Logical and";
Buildings.Controls.OBC.CDL.Continuous.Switch swi2
"Airflow setpoint when it is in heating state";
Buildings.Controls.OBC.CDL.Continuous.Switch swi3
"Airflow setpoint when it is in heating state";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant conZer3(
final k=0)
"Constant zero";
Buildings.Controls.OBC.CDL.Continuous.Subtract sub3
"Calculate flow rate difference between minimum flow setpoint and measured discharge flow";
Buildings.Controls.OBC.CDL.Continuous.Max max1
"Ensure positive flow";
Buildings.Controls.OBC.CDL.Conversions.BooleanToReal booToRea2(
final realTrue=1,
final realFalse=0)
"Convert boolean to real";
Buildings.Controls.OBC.CDL.Continuous.Multiply mul3
"Cold duct flow setpoint when in heating state";
Buildings.Controls.OBC.CDL.Continuous.Divide VDisSet_flowNor
"Normalized setpoint for discharge volume flow rate";
Buildings.Controls.OBC.CDL.Continuous.PIDWithReset conCooDam(
final controllerType=controllerTypeDam,
final k=kDam,
final Ti=TiDam,
final Td=TdDam,
final yMax=1,
final yMin=0,
final y_reset=0) if not have_preIndDam
"Cooling damper position controller";
Buildings.Controls.OBC.CDL.Continuous.Divide VDis_flowNor
if not have_preIndDam
"Normalized discharge volume flow rate";
Buildings.Controls.OBC.CDL.Continuous.Switch cooDamPos
"Output cooling damper position";
Buildings.Controls.OBC.CDL.Logical.Not not3
"Not proven on";
Buildings.Controls.OBC.CDL.Continuous.MultiplyByParameter gai(
final k=1)
if have_preIndDam
"Block that can be disabled so remove the connection";
Buildings.Controls.OBC.CDL.Continuous.Divide VDisSet_flowNor1
"Normalized setpoint for discharge volume flow rate";
Buildings.Controls.OBC.CDL.Continuous.PIDWithReset conHeaDam(
final controllerType=Buildings.Controls.OBC.CDL.Types.SimpleController.P,
final k=kHeaMaxDam,
final yMax=1,
final yMin=0,
final y_reset=0) if not have_preIndDam
"Heating damper position controller";
Buildings.Controls.OBC.CDL.Continuous.Divide VDis_flowNor1
if not have_preIndDam
"Normalized discharge volume flow rate";
Buildings.Controls.OBC.CDL.Continuous.MultiplyByParameter gai1(
final k=1)
if have_preIndDam
"Block that can be disabled so remove the connection";
Buildings.Controls.OBC.CDL.Continuous.Switch heaDamPos
"Output heating damper position";
Buildings.Controls.OBC.CDL.Logical.Or or1
"Cooing or deadband state";
Buildings.Controls.OBC.CDL.Conversions.BooleanToReal booToRea1(
final realTrue=0,
final realFalse=1)
"Ensure heating damper is closed when it is in cooling or deadband state";
Buildings.Controls.OBC.CDL.Continuous.Multiply mul1
"Ensure heating damper is closed when it is in cooling or deadband state";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant conZer1(
final k=0)
"Constant zero";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant conOne1(
final k=1)
"Constant one";
Buildings.Controls.OBC.CDL.Continuous.Line lin1
"Active airflow setpoint for heating";
Buildings.Controls.OBC.CDL.Continuous.Add add2
"Total discharge airflow setpoint";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant cooMax1(
final k=VCooMax_flow)
"Cooling maximum flow";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant heaMax1(
final k=VHeaMax_flow)
"Heating maximum flow";
Buildings.Controls.OBC.CDL.Continuous.Max max2
"Nominal flow";
equation
connect(uCoo, lin.u);
connect(conZer.y, lin.x1);
connect(conOne.y, lin.x2);
connect(VActCooMax_flow, lin.f2);
connect(uCoo, greThr1.u);
connect(and4.y, swi5.u2);
connect(lin.y, swi5.u3);
connect(swi5.y, swi.u1);
connect(TColSup, sub2.u1);
connect(sub2.y, greThr.u);
connect(greThr.y, and4.u2);
connect(greThr1.y, and4.u1);
connect(greThr1.y, swi.u2);
connect(TZon, sub2.u2);
connect(VActMin_flow, swi5.u1);
connect(greThr1.y, or2.u1);
connect(uHea, greThr2.u);
connect(greThr2.y, or2.u2);
connect(or2.y, not1.u);
connect(not1.y, swi1.u2);
connect(VActMin_flow, swi1.u1);
connect(swi1.y, swi.u3);
connect(TZon, sub1.u1);
connect(THotSup, sub1.u2);
connect(sub1.y, greThr3.u);
connect(greThr3.y, and1.u1);
connect(greThr2.y, and1.u2);
connect(and1.y, swi2.u2);
connect(greThr2.y, swi3.u2);
connect(swi2.y, swi3.u1);
connect(conZer3.y, swi3.u3);
connect(VActMin_flow, sub3.u1);
connect(sub3.y, max1.u2);
connect(conZer3.y, max1.u1);
connect(greThr2.y, booToRea2.u);
connect(booToRea2.y, mul3.u1);
connect(max1.y, mul3.u2);
connect(mul3.y, swi1.u3);
connect(swi.y, VColDucDis_flow_Set);
connect(swi.y, VDisSet_flowNor.u1);
connect(VDisSet_flowNor.y, conCooDam.u_s);
connect(VDis_flow, VDis_flowNor.u1);
connect(VDis_flowNor.y, conCooDam.u_m);
connect(u1CooAHU, conCooDam.trigger);
connect(u1CooAHU, not3.u);
connect(not3.y, cooDamPos.u2);
connect(VDisSet_flowNor.y, gai.u);
connect(gai.y, cooDamPos.u3);
connect(conCooDam.y, cooDamPos.u3);
connect(conZer3.y, cooDamPos.u1);
connect(cooDamPos.y, yCooDam);
connect(heaDamPos.y, yHeaDam);
connect(u1HeaAHU, heaDamPos.u2);
connect(conZer3.y, heaDamPos.u3);
connect(VDisSet_flowNor1.y, conHeaDam.u_s);
connect(VDis_flowNor1.y, conHeaDam.u_m);
connect(u1HeaAHU, conHeaDam.trigger);
connect(greThr1.y, or1.u1);
connect(or2.y, or1.u2);
connect(or1.y, booToRea1.u);
connect(booToRea1.y, mul1.u2);
connect(VDisSet_flowNor1.y, gai1.u);
connect(mul1.y, heaDamPos.u1);
connect(VActMin_flow, lin.f1);
connect(conZer3.y, swi2.u1);
connect(VDis_flow, VDis_flowNor1.u1);
connect(conZer1.y, lin1.x1);
connect(conZer1.y, lin1.f1);
connect(conOne1.y, lin1.x2);
connect(VActHeaMax_flow, lin1.f2);
connect(uHea, lin1.u);
connect(lin1.y, swi2.u3);
connect(swi2.y, sub3.u2);
connect(swi3.y, VDisSet_flowNor1.u1);
connect(conHeaDam.y, mul1.u1);
connect(gai1.y, mul1.u1);
connect(swi.y, add2.u1);
connect(swi3.y, add2.u2);
connect(add2.y, VDis_flow_Set);
connect(cooMax1.y,max2. u1);
connect(heaMax1.y,max2. u2);
connect(max2.y, VDisSet_flowNor.u2);
connect(max2.y, VDis_flowNor.u2);
connect(max2.y, VDisSet_flowNor1.u2);
connect(max2.y, VDis_flowNor1.u2);
end Dampers;
Buildings.Controls.OBC.ASHRAE.G36.TerminalUnits.DualDuctMixConDischargeSensor.Subsequences.Overrides
Software switches to override setpoints
Information
This block considers the overrides to the setpoints for dual-duct terminal unit using mixing control with discharge flow sensor. The implementation is according to the Section 5.13.7 of ASHRAE Guideline 36, May 2020.
Provide software switches that interlock to a system-level point to:
-
when
oveFloSetequals to 1, force the zone airflow setpointVSet_flowto zero, -
when
oveFloSetequals to 2, force the zone airflow setpointVSet_flowto zone cooling maximum airflow rateVCooMax_flow, -
when
oveFloSetequals to 3, force the zone airflow setpointVSet_flowto zone minimum airflow setpointVMin_flow. -
when
oveFloSetequals to 4, force the zone airflow setpointVSet_flowto zone heating maximum airflow setpointVHeaMax_flow. -
when
oveCooDamPosequals to 1, force the cooling damper to full closed by settingyCooDamto 0, -
when
oveCooDamPosequals to 2, force the cooling damper to full open by settingyCooDamto 1. -
when
oveHeaDamPosequals to 1, force the heating damper to full closed by settingyHeaDamto 0, -
when
oveHeaDamPosequals to 2, force the heating damper to full open by settingyHeaDamto 1.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Real | VMin_flow | Design zone minimum airflow setpoint [m3/s] | |
| Real | VCooMax_flow | Design zone cooling maximum airflow rate [m3/s] | |
| Real | VHeaMax_flow | Design zone heating maximum airflow rate [m3/s] |
Connectors
| Type | Name | Description |
|---|---|---|
| input IntegerInput | oveFloSet | Index of overriding flow setpoint, 1: set to zero; 2: set to cooling maximum; 3: set to minimum flow; 4: set to heating maximum |
| input RealInput | VActSet_flow | Active airflow setpoint [m3/s] |
| input IntegerInput | oveCooDamPos | Index of overriding cooling damper position, 1: set to close; 2: set to open |
| input RealInput | uCooDam | Cooling damper commanded position [1] |
| input IntegerInput | oveHeaDamPos | Index of overriding heating damper position, 1: set to close; 2: set to open |
| input RealInput | uHeaDam | Heating damper commanded position [1] |
| output RealOutput | VSet_flow | Airflow setpoint after considering override [m3/s] |
| output RealOutput | yCooDam | Cooling damper position setpoint after considering override [1] |
| output RealOutput | yHeaDam | Heating damper position setpoint after considering override [1] |
Modelica definition
block Overrides "Software switches to override setpoints"
parameter Real VMin_flow(
final quantity="VolumeFlowRate",
final unit="m3/s")
"Design zone minimum airflow setpoint";
parameter Real VCooMax_flow(
final quantity="VolumeFlowRate",
final unit="m3/s")
"Design zone cooling maximum airflow rate";
parameter Real VHeaMax_flow(
final quantity="VolumeFlowRate",
final unit="m3/s")
"Design zone heating maximum airflow rate";
Buildings.Controls.OBC.CDL.Interfaces.IntegerInput oveFloSet
"Index of overriding flow setpoint, 1: set to zero; 2: set to cooling maximum; 3: set to minimum flow; 4: set to heating maximum";
Buildings.Controls.OBC.CDL.Interfaces.RealInput VActSet_flow(
final min=0,
final unit="m3/s",
final quantity="VolumeFlowRate")
"Active airflow setpoint";
Buildings.Controls.OBC.CDL.Interfaces.IntegerInput oveCooDamPos
"Index of overriding cooling damper position, 1: set to close; 2: set to open";
Buildings.Controls.OBC.CDL.Interfaces.RealInput uCooDam(
final min=0,
final unit="1")
"Cooling damper commanded position";
Buildings.Controls.OBC.CDL.Interfaces.IntegerInput oveHeaDamPos
"Index of overriding heating damper position, 1: set to close; 2: set to open";
Buildings.Controls.OBC.CDL.Interfaces.RealInput uHeaDam(
final min=0,
final unit="1")
"Heating damper commanded position";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput VSet_flow(
final min=0,
final unit="m3/s",
final quantity="VolumeFlowRate")
"Airflow setpoint after considering override";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput yCooDam(
final min=0,
final unit="1")
"Cooling damper position setpoint after considering override";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput yHeaDam(
final min=0,
final unit="1")
"Heating damper position setpoint after considering override";
Buildings.Controls.OBC.CDL.Integers.Sources.Constant conInt(
final k=1)
"Constant 1";
Buildings.Controls.OBC.CDL.Integers.Equal forZerFlo "Check if forcing zone airflow setpoint to zero";
Buildings.Controls.OBC.CDL.Integers.Equal forCooMax
"Check if forcing zone airflow setpoint to cooling maximum";
Buildings.Controls.OBC.CDL.Integers.Sources.Constant conInt1(
final k=2)
"Constant 2";
Buildings.Controls.OBC.CDL.Integers.Equal forMinFlo
"Check if forcing zone airflow setpoint to minimum flow";
Buildings.Controls.OBC.CDL.Integers.Sources.Constant conInt2(
final k=3)
"Constant 3";
Buildings.Controls.OBC.CDL.Conversions.BooleanToReal zerFlo(
final realTrue=0)
"Force zone airflow setpoint to zero";
Buildings.Controls.OBC.CDL.Conversions.BooleanToReal cooMax(
final realTrue=VCooMax_flow)
"Force zone airflow setpoint to cooling maximum";
Buildings.Controls.OBC.CDL.Conversions.BooleanToReal minFlo(
final realTrue=VMin_flow)
"Force zone airflow setpoint to zone minimum flow";
Buildings.Controls.OBC.CDL.Continuous.Add add2 "Add up two inputs";
Buildings.Controls.OBC.CDL.Continuous.Add add1 "Add up inputs";
Buildings.Controls.OBC.CDL.Continuous.Switch swi "Airflow setpoint after considering override";
Buildings.Controls.OBC.CDL.Logical.Or3 or3 "Check if the airflow setpoint should be overrided";
Buildings.Controls.OBC.CDL.Integers.Sources.Constant conInt3(
final k=1)
"Constant 1";
Buildings.Controls.OBC.CDL.Integers.Equal intEqu3
"Check if forcing damper to full close";
Buildings.Controls.OBC.CDL.Integers.Equal intEqu4
"Check if forcing damper to full open";
Buildings.Controls.OBC.CDL.Integers.Sources.Constant conInt4(
final k=2)
"Constant 2";
Buildings.Controls.OBC.CDL.Conversions.BooleanToReal cloDam(
final realTrue=0)
"Full closed damper position";
Buildings.Controls.OBC.CDL.Conversions.BooleanToReal opeDam(
final realTrue=1)
"Full open damper position";
Buildings.Controls.OBC.CDL.Continuous.Add add3 "Add up inputs";
Buildings.Controls.OBC.CDL.Logical.Or or2
"Check if the damper setpoint position should be overrided";
Buildings.Controls.OBC.CDL.Continuous.Switch swi1
"Damper setpoint position after considering override";
Buildings.Controls.OBC.CDL.Integers.Sources.Constant conInt5(
final k=4)
"Constant 4";
Buildings.Controls.OBC.CDL.Integers.Equal forMinFlo1
"Check if forcing zone airflow setpoint to minimum flow";
Buildings.Controls.OBC.CDL.Conversions.BooleanToReal heaMax(
final realTrue=VHeaMax_flow)
"Force zone airflow setpoint to zone heating maximum flow";
Buildings.Controls.OBC.CDL.Continuous.Add add4
"Add up two inputs";
Buildings.Controls.OBC.CDL.Logical.Or or1
"Check if the airflow setpoint should be overrided";
Buildings.Controls.OBC.CDL.Integers.Sources.Constant conInt6(
final k=1)
"Constant 1";
Buildings.Controls.OBC.CDL.Integers.Equal intEqu1
"Check if forcing damper to full close";
Buildings.Controls.OBC.CDL.Integers.Equal intEqu2
"Check if forcing damper to full open";
Buildings.Controls.OBC.CDL.Integers.Sources.Constant conInt7(
final k=2)
"Constant 2";
Buildings.Controls.OBC.CDL.Conversions.BooleanToReal cloDam1(
final realTrue=0)
"Full closed damper position";
Buildings.Controls.OBC.CDL.Conversions.BooleanToReal opeDam1(
final realTrue=1)
"Full open damper position";
Buildings.Controls.OBC.CDL.Continuous.Add add5
"Add up inputs";
Buildings.Controls.OBC.CDL.Logical.Or or4
"Check if the damper setpoint position should be overrided";
Buildings.Controls.OBC.CDL.Continuous.Switch swi2
"Damper setpoint position after considering override";
equation
connect(oveFloSet, forZerFlo.u1);
connect(conInt.y, forZerFlo.u2);
connect(oveFloSet, forCooMax.u1);
connect(conInt1.y, forCooMax.u2);
connect(oveFloSet, forMinFlo.u1);
connect(conInt2.y, forMinFlo.u2);
connect(forZerFlo.y, zerFlo.u);
connect(forCooMax.y, cooMax.u);
connect(forMinFlo.y, minFlo.u);
connect(cooMax.y, add2.u1);
connect(zerFlo.y, add1.u1);
connect(forZerFlo.y, or3.u1);
connect(forCooMax.y, or3.u2);
connect(forMinFlo.y, or3.u3);
connect(add1.y, swi.u1);
connect(VActSet_flow, swi.u3);
connect(swi.y, VSet_flow);
connect(conInt3.y, intEqu3.u2);
connect(conInt4.y,intEqu4. u2);
connect(oveCooDamPos, intEqu3.u1);
connect(oveCooDamPos, intEqu4.u1);
connect(intEqu3.y, cloDam.u);
connect(intEqu4.y, opeDam.u);
connect(cloDam.y, add3.u1);
connect(opeDam.y, add3.u2);
connect(intEqu3.y, or2.u1);
connect(intEqu4.y, or2.u2);
connect(add3.y, swi1.u1);
connect(or2.y, swi1.u2);
connect(uCooDam, swi1.u3);
connect(swi1.y, yCooDam);
connect(oveFloSet, forMinFlo1.u1);
connect(conInt5.y, forMinFlo1.u2);
connect(forMinFlo1.y, heaMax.u);
connect(add2.y, add1.u2);
connect(minFlo.y, add4.u1);
connect(heaMax.y, add4.u2);
connect(add4.y, add2.u2);
connect(or3.y, or1.u1);
connect(forMinFlo1.y, or1.u2);
connect(or1.y, swi.u2);
connect(conInt6.y,intEqu1. u2);
connect(conInt7.y,intEqu2. u2);
connect(oveHeaDamPos, intEqu1.u1);
connect(oveHeaDamPos, intEqu2.u1);
connect(intEqu1.y, cloDam1.u);
connect(intEqu2.y, opeDam1.u);
connect(cloDam1.y, add5.u1);
connect(opeDam1.y, add5.u2);
connect(intEqu1.y,or4. u1);
connect(intEqu2.y,or4. u2);
connect(add5.y,swi2. u1);
connect(or4.y,swi2. u2);
connect(uHeaDam, swi2.u3);
connect(swi2.y, yHeaDam);
end Overrides;
Buildings.Controls.OBC.ASHRAE.G36.TerminalUnits.DualDuctMixConDischargeSensor.Subsequences.SystemRequests
Output system requests for dual-duct unit using mixing control with discharge flow sensor
Information
This sequence outputs the system reset requests for dual-duct terminal unit using mixing control with discharge flow sensor. The implementation is according to the Section 5.13.8 of ASHRAE Guideline 36, May 2020.
Cooling SAT reset requests yZonCooTemResReq
-
If the zone temperature
TZonexceeds the zone cooling setpointTCooSetby 3 °C (5 °F)) for 2 minutes and after suppression period (uAftSupCoo=true) due to setpoint change per G36 Part 5.1.20, send 3 requests (yZonCooTemResReq=3). -
Else if the zone temperature
TZonexceeds the zone cooling setpointTCooSetby 2 °C (3 °F) for 2 minutes and after suppression period (uAftSupCoo=true) due to setpoint change per G36 Part 5.1.20, send 2 requests (yZonCooTemResReq=3). -
Else if the cooling loop
uCoois greater than 95%, send 1 request (yZonCooTemResReq=1) untiluCoois less than 85%. -
Else if
uCoois less than 95%, send 0 request (yZonCooTemResReq=0).
Cold-duct static pressure reset requests yColDucPreResReq
When the zone is in cooling or deadband state:
-
If the measured airflow
VDis_flowis less than 50% of setpointVDis_flow_Setwhile the setpoint is greater than zero and the damper positionuCooDamis greater than 95% for 1 minute, send 3 requests (yColDucPreResReq=3). -
Else if the measured airflow
VDis_flowis less than 70% of setpointVDis_flow_Setwhile the setpoint is greater than zero and the damper positionuCooDamis greater than 95% for 1 minute, send 2 requests (yColDucPreResReq=2). -
Else if the damper position
uCooDamis greater than 95%, send 1 request (yColDucPreResReq=1) untiluDamis less than 85%. -
Else if the damper position
uCooDamis less than 95%, send 0 request (yColDucPreResReq=0).
Heating SAT reset requests yZonHeaTemResReq
-
If the zone temperature
TZonis below the zone heating setpointTHeaSetby 3 °C (5 °F)) for 2 minutes and after suppression period (uAftSupHea=true) due to setpoint change per G36 Part 5.1.20, send 3 requests (yZonHeaTemResReq=3). -
Else if the zone temperature
TZonis below the zone heating setpointTHeaSetby 2 °C (3 °F) for 2 minutes and after suppression period (uAftSupHea=true) due to setpoint change per G36 Part 5.1.20, send 2 requests (yZonHeaTemResReq=3). -
Else if the heating loop
uHeais greater than 95%, send 1 request (yZonHeaTemResReq=1) untiluHeais less than 85%. -
Else if
uHeais less than 95%, send 0 request (yZonHeaTemResReq=0).
Hot-duct static pressure reset requests yHotDucPreResReq
When the zone is in heating state:
-
If the measured airflow
VDis_flowis less than 50% of setpointVDis_flow_Setwhile the setpoint is greater than zero and the damper positionuHeaDamis greater than 95% for 1 minute, send 3 requests (yHotDucPreResReq=3). -
Else if the measured airflow
VDis_flowis less than 70% of setpointVDis_flow_Setwhile the setpoint is greater than zero and the damper positionuHeaDamis greater than 95% for 1 minute, send 2 requests (yHotDucPreResReq=2). -
Else if the damper position
uHeaDamis greater than 95%, send 1 request (yHotDucPreResReq=1) untiluHeaDamis less than 85%. -
Else if the damper position
uHeaDamis less than 95%, send 0 request (yHotDucPreResReq=0).
Heating-fan requests
Send the heating fan that serves the zone a heating-fan request as follows:
- If the heating loop is greater than 15%, send 1 request until the heating loop is less than 1%.
- Else if the heatling loop is less than 15%, send 0 requests.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Real | thrTemDif | 3 | Threshold difference between zone temperature and cooling setpoint for generating 3 cooling SAT reset requests [K] |
| Real | twoTemDif | 2 | Threshold difference between zone temperature and cooling setpoint for generating 2 cooling SAT reset requests [K] |
| Duration times | |||
| Real | durTimTem | 120 | Duration time of zone temperature exceeds setpoint [s] |
| Real | durTimFlo | 60 | Duration time of airflow rate less than setpoint [s] |
| Advanced | |||
| Real | dTHys | 0.25 | Near zero temperature difference, below which the difference will be seen as zero [K] |
| Real | floHys | Near zero flow rate, below which the flow rate or difference will be seen as zero [m3/s] | |
| Real | looHys | Loop output hysteresis below which the output will be seen as zero [1] | |
| Real | damPosHys | Near zero damper position, below which the damper will be seen as closed [1] | |
Connectors
| Type | Name | Description |
|---|---|---|
| input BooleanInput | uAftSupCoo | After suppression period due to the cooling setpoint change |
| input RealInput | TCooSet | Zone cooling setpoint temperature [K] |
| input RealInput | TZon | Zone temperature [K] |
| input RealInput | uCoo | Cooling loop signal [1] |
| input BooleanInput | uAftSupHea | After suppression period due to the heating setpoint change |
| input RealInput | THeaSet | Zone heating setpoint temperature [K] |
| input RealInput | uHea | Heating loop signal [1] |
| input RealInput | VDis_flow_Set | Discharge airflow rate setpoint [m3/s] |
| input RealInput | VDis_flow | Measured discharge airflow rate [m3/s] |
| input RealInput | uCooDam | Cooling damper position setpoint [1] |
| input RealInput | uHeaDam | Heating damper position setpoint [1] |
| output IntegerOutput | yZonCooTemResReq | Zone cooling supply air temperature reset request |
| output IntegerOutput | yColDucPreResReq | Cold duct static pressure reset requests |
| output IntegerOutput | yZonHeaTemResReq | Zone heating supply air temperature reset request |
| output IntegerOutput | yHotDucPreResReq | Hot duct static pressure reset requests |
| output IntegerOutput | yHeaFanReq | Heating fan request |
Modelica definition
block SystemRequests
"Output system requests for dual-duct unit using mixing control with discharge flow sensor"
parameter Real thrTemDif(
final unit="K",
final quantity="TemperatureDifference")=3
"Threshold difference between zone temperature and cooling setpoint for generating 3 cooling SAT reset requests";
parameter Real twoTemDif(
final unit="K",
final quantity="TemperatureDifference")=2
"Threshold difference between zone temperature and cooling setpoint for generating 2 cooling SAT reset requests";
parameter Real durTimTem(
final unit="s",
final quantity="Time")=120
"Duration time of zone temperature exceeds setpoint";
parameter Real durTimFlo(
final unit="s",
final quantity="Time")=60
"Duration time of airflow rate less than setpoint";
parameter Real dTHys(
final unit="K",
final quantity="TemperatureDifference")=0.25
"Near zero temperature difference, below which the difference will be seen as zero";
parameter Real floHys(
final quantity="VolumeFlowRate",
final unit="m3/s")
"Near zero flow rate, below which the flow rate or difference will be seen as zero";
parameter Real looHys(unit="1")
"Loop output hysteresis below which the output will be seen as zero";
parameter Real damPosHys(
final unit="1")
"Near zero damper position, below which the damper will be seen as closed";
Buildings.Controls.OBC.CDL.Interfaces.BooleanInput uAftSupCoo
"After suppression period due to the cooling setpoint change";
Buildings.Controls.OBC.CDL.Interfaces.RealInput TCooSet(
final unit="K",
final displayUnit="degC",
final quantity="ThermodynamicTemperature")
"Zone cooling setpoint temperature";
Buildings.Controls.OBC.CDL.Interfaces.RealInput TZon(
final unit="K",
final displayUnit="degC",
final quantity="ThermodynamicTemperature")
"Zone temperature";
Buildings.Controls.OBC.CDL.Interfaces.RealInput uCoo(
final min=0,
final max=1,
final unit="1") "Cooling loop signal";
Buildings.Controls.OBC.CDL.Interfaces.BooleanInput uAftSupHea
"After suppression period due to the heating setpoint change";
Buildings.Controls.OBC.CDL.Interfaces.RealInput THeaSet(
final unit="K",
final displayUnit="degC",
final quantity="ThermodynamicTemperature")
"Zone heating setpoint temperature";
Buildings.Controls.OBC.CDL.Interfaces.RealInput uHea(
final min=0,
final max=1,
final unit="1")
"Heating loop signal";
Buildings.Controls.OBC.CDL.Interfaces.RealInput VDis_flow_Set(
final min=0,
final unit="m3/s",
quantity="VolumeFlowRate")
"Discharge airflow rate setpoint";
Buildings.Controls.OBC.CDL.Interfaces.RealInput VDis_flow(
final min=0,
final unit="m3/s",
final quantity="VolumeFlowRate")
"Measured discharge airflow rate";
Buildings.Controls.OBC.CDL.Interfaces.RealInput uCooDam(
final min=0,
final max=1,
final unit="1") "Cooling damper position setpoint";
Buildings.Controls.OBC.CDL.Interfaces.RealInput uHeaDam(
final min=0,
final max=1,
final unit="1") "Heating damper position setpoint";
Buildings.Controls.OBC.CDL.Interfaces.IntegerOutput yZonCooTemResReq
"Zone cooling supply air temperature reset request";
Buildings.Controls.OBC.CDL.Interfaces.IntegerOutput yColDucPreResReq
"Cold duct static pressure reset requests";
Buildings.Controls.OBC.CDL.Interfaces.IntegerOutput yZonHeaTemResReq
"Zone heating supply air temperature reset request";
Buildings.Controls.OBC.CDL.Interfaces.IntegerOutput yHotDucPreResReq
"Hot duct static pressure reset requests";
Buildings.Controls.OBC.CDL.Interfaces.IntegerOutput yHeaFanReq
"Heating fan request";
protected
Buildings.Controls.OBC.CDL.Continuous.GreaterThreshold greThr1(
final t=thrTemDif,
final h=dTHys)
"Check if zone temperature is greater than cooling setpoint by threshold";
Buildings.Controls.OBC.CDL.Continuous.GreaterThreshold greThr2(
final t=twoTemDif,
final h=dTHys)
"Check if zone temperature is greater than cooling setpoint by threshold";
Buildings.Controls.OBC.CDL.Continuous.GreaterThreshold greThr3(
final t=0.95,
final h=damPosHys)
"Check if damper position is greater than 0.95";
Buildings.Controls.OBC.CDL.Continuous.GreaterThreshold greThr(
final t=0.95,
final h=looHys)
"Check if cooling loop signal is greater than 0.95";
Buildings.Controls.OBC.CDL.Continuous.GreaterThreshold greThr4(
final t=floHys,
final h=0.5*floHys)
"Check if discharge airflow setpoint is greater than 0";
Buildings.Controls.OBC.CDL.Conversions.BooleanToInteger booToInt
"Convert boolean to integer";
Buildings.Controls.OBC.CDL.Conversions.BooleanToInteger booToInt1
"Convert boolean to integer";
Buildings.Controls.OBC.CDL.Continuous.MultiplyByParameter gai1(
final k=0.5)
"50% of setpoint";
Buildings.Controls.OBC.CDL.Continuous.MultiplyByParameter gai2(
final k=0.7)
"70% of setpoint";
Buildings.Controls.OBC.CDL.Continuous.Subtract sub2
"Calculate difference between zone temperature and cooling setpoint";
Buildings.Controls.OBC.CDL.Continuous.Subtract sub3
"Calculate difference between zone temperature and cooling setpoint";
Buildings.Controls.OBC.CDL.Logical.And and1
"Logical and";
Buildings.Controls.OBC.CDL.Logical.And and2
"Logical and";
Buildings.Controls.OBC.CDL.Logical.And and3
"Logical and";
Buildings.Controls.OBC.CDL.Logical.And and4
"Logical and";
Buildings.Controls.OBC.CDL.Integers.Sources.Constant thrCooResReq(
final k=3)
"Constant 3";
Buildings.Controls.OBC.CDL.Integers.Sources.Constant twoCooResReq(
final k=2) "Constant 2";
Buildings.Controls.OBC.CDL.Integers.Sources.Constant thrPreResReq(
final k=3) "Constant 3";
Buildings.Controls.OBC.CDL.Integers.Sources.Constant twoPreResReq(
final k=2)
"Constant 2";
Buildings.Controls.OBC.CDL.Integers.Switch intSwi
"Output 3 or other request ";
Buildings.Controls.OBC.CDL.Integers.Switch intSwi1
"Output 2 or other request ";
Buildings.Controls.OBC.CDL.Integers.Switch swi4
"Output 3 or other request ";
Buildings.Controls.OBC.CDL.Integers.Switch swi5
"Output 2 or other request ";
Buildings.Controls.OBC.CDL.Logical.TrueDelay tim1(
final delayTime=durTimTem) "Check if it is more than threshold time";
Buildings.Controls.OBC.CDL.Logical.TrueDelay tim2(
final delayTime=durTimTem) "Check if it is more than threshold time";
Buildings.Controls.OBC.CDL.Logical.TrueDelay tim3(
final delayTime=durTimFlo) "Check if it is more than threshold time";
Buildings.Controls.OBC.CDL.Continuous.Greater greEqu(final h=floHys)
"Check if discharge airflow is less than 50% of setpoint";
Buildings.Controls.OBC.CDL.Continuous.Greater greEqu1(final h=floHys)
"Check if discharge airflow is less than 70% of setpoint";
Buildings.Controls.OBC.CDL.Logical.And and5
"Logical and";
Buildings.Controls.OBC.CDL.Continuous.GreaterThreshold greThr7(
final t=thrTemDif,
final h=dTHys)
"Check if zone temperature is less than heating setpoint by threshold";
Buildings.Controls.OBC.CDL.Continuous.GreaterThreshold greThr8(
final t=twoTemDif,
final h=dTHys)
"Check if zone temperature is less than heating setpoint by threshold";
Buildings.Controls.OBC.CDL.Continuous.GreaterThreshold greThr9(
final t=0.95,
final h=damPosHys)
"Check if damper position is greater than 0.95";
Buildings.Controls.OBC.CDL.Continuous.GreaterThreshold greThr10(
final t=0.95,
final h=looHys) "Check if heating loop signal is greater than 0.95";
Buildings.Controls.OBC.CDL.Conversions.BooleanToInteger booToInt4
"Convert boolean to integer";
Buildings.Controls.OBC.CDL.Conversions.BooleanToInteger booToInt5
"Convert boolean to integer";
Buildings.Controls.OBC.CDL.Continuous.Subtract sub1
"Calculate difference between zone temperature and heating setpoint";
Buildings.Controls.OBC.CDL.Continuous.Subtract sub4
"Calculate difference between zone temperature and heating setpoint";
Buildings.Controls.OBC.CDL.Logical.And and6
"Logical and";
Buildings.Controls.OBC.CDL.Logical.And and7
"Logical and";
Buildings.Controls.OBC.CDL.Logical.And and8
"Logical and";
Buildings.Controls.OBC.CDL.Logical.And and9
"Logical and";
Buildings.Controls.OBC.CDL.Integers.Sources.Constant thrCooResReq1(
final k=3)
"Constant 3";
Buildings.Controls.OBC.CDL.Integers.Sources.Constant twoCooResReq1(
final k=2)
"Constant 2";
Buildings.Controls.OBC.CDL.Integers.Sources.Constant thrPreResReq1(
final k=3)
"Constant 3";
Buildings.Controls.OBC.CDL.Integers.Sources.Constant twoPreResReq1(
final k=2)
"Constant 2";
Buildings.Controls.OBC.CDL.Integers.Switch intSwi4
"Output 3 or other request ";
Buildings.Controls.OBC.CDL.Integers.Switch intSwi5
"Output 2 or other request ";
Buildings.Controls.OBC.CDL.Integers.Switch swi1
"Output 3 or other request ";
Buildings.Controls.OBC.CDL.Integers.Switch swi2
"Output 2 or other request ";
Buildings.Controls.OBC.CDL.Logical.TrueDelay tim6(
final delayTime=durTimTem)
"Check if it is more than threshold time";
Buildings.Controls.OBC.CDL.Logical.TrueDelay tim7(
final delayTime=durTimTem)
"Check if it is more than threshold time";
Buildings.Controls.OBC.CDL.Logical.TrueDelay tim8(
final delayTime=durTimFlo)
"Check if it is more than threshold time";
Buildings.Controls.OBC.CDL.Logical.And and10
"Logical and";
Buildings.Controls.OBC.CDL.Continuous.GreaterThreshold greThr12(
final t=0.15,
final h=looHys)
"Check if heating loop signal is greater than 0.15";
Buildings.Controls.OBC.CDL.Logical.Latch lat "Hold the true input";
Buildings.Controls.OBC.CDL.Continuous.LessThreshold lesThr(
final t=0.01,
final h=looHys)
"Check if the heating loop output is less than threshold";
Buildings.Controls.OBC.CDL.Conversions.BooleanToInteger booToInt6
"Heating fan request";
Buildings.Controls.OBC.CDL.Continuous.GreaterThreshold greThr5(
final t=looHys,
final h=0.5*looHys)
"Check if it is heating state";
Buildings.Controls.OBC.CDL.Continuous.GreaterThreshold greThr6(
final t=looHys,
final h=0.5*looHys)
"Check if it is heating state";
Buildings.Controls.OBC.CDL.Continuous.GreaterThreshold greThr13(
final t=looHys,
final h=0.5*looHys)
"Check if it is cooling state";
Buildings.Controls.OBC.CDL.Logical.Or or2
"Cooing or heating state";
Buildings.Controls.OBC.CDL.Logical.Not not1
"In deadband state";
Buildings.Controls.OBC.CDL.Logical.Or or1
"Cooing or deadband state";
Buildings.Controls.OBC.CDL.Conversions.BooleanToInteger booToInt3
"Convert boolean to integer";
Buildings.Controls.OBC.CDL.Integers.Multiply mulInt2
"Ensure zero request when the it is not in heating state";
Buildings.Controls.OBC.CDL.Conversions.BooleanToInteger booToInt2
"Convert boolean to integer";
Buildings.Controls.OBC.CDL.Integers.Multiply mulInt1
"Ensure zero request when it is in heating state";
equation
connect(sub2.y, greThr1.u);
connect(and2.y, intSwi.u2);
connect(sub3.y, greThr2.u);
connect(and1.y, intSwi1.u2);
connect(and3.y, swi4.u2);
connect(and4.y, swi5.u2);
connect(greThr2.y, tim2.u);
connect(tim2.y, and1.u2);
connect(greThr1.y, tim1.u);
connect(tim1.y, and2.u2);
connect(greThr4.u, VDis_flow_Set);
connect(greEqu.u1, gai1.y);
connect(greEqu.y, and3.u2);
connect(gai2.y, greEqu1.u1);
connect(greEqu1.y, and4.u2);
connect(uCoo, greThr.u);
connect(uAftSupCoo, and2.u1);
connect(uAftSupCoo, and1.u1);
connect(thrCooResReq.y, intSwi.u1);
connect(twoCooResReq.y, intSwi1.u1);
connect(intSwi1.y, intSwi.u3);
connect(intSwi.y, yZonCooTemResReq);
connect(greThr.y, booToInt.u);
connect(booToInt.y, intSwi1.u3);
connect(uCooDam, greThr3.u);
connect(VDis_flow_Set, gai1.u);
connect(VDis_flow_Set, gai2.u);
connect(VDis_flow, greEqu.u2);
connect(VDis_flow, greEqu1.u2);
connect(greThr3.y, tim3.u);
connect(greThr4.y, and5.u1);
connect(tim3.y, and5.u2);
connect(and5.y, and3.u1);
connect(and5.y, and4.u1);
connect(greThr3.y, booToInt1.u);
connect(booToInt1.y, swi5.u3);
connect(twoPreResReq.y, swi5.u1);
connect(thrPreResReq.y, swi4.u1);
connect(swi5.y, swi4.u3);
connect(TCooSet, sub3.u2);
connect(TCooSet, sub2.u2);
connect(TZon, sub2.u1);
connect(TZon, sub3.u1);
connect(sub1.y,greThr7. u);
connect(and7.y, intSwi4.u2);
connect(sub4.y,greThr8. u);
connect(and6.y,intSwi5. u2);
connect(and8.y,swi1. u2);
connect(and9.y,swi2. u2);
connect(greThr8.y,tim7. u);
connect(tim7.y,and6. u2);
connect(greThr7.y,tim6. u);
connect(tim6.y,and7. u2);
connect(uHea, greThr10.u);
connect(uAftSupHea, and7.u1);
connect(uAftSupHea, and6.u1);
connect(thrCooResReq1.y, intSwi4.u1);
connect(twoCooResReq1.y, intSwi5.u1);
connect(intSwi5.y, intSwi4.u3);
connect(intSwi4.y, yZonHeaTemResReq);
connect(greThr10.y, booToInt4.u);
connect(booToInt4.y, intSwi5.u3);
connect(uHeaDam, greThr9.u);
connect(greThr9.y,tim8. u);
connect(tim8.y, and10.u2);
connect(and10.y, and8.u1);
connect(and10.y, and9.u1);
connect(greThr9.y,booToInt5. u);
connect(booToInt5.y,swi2. u3);
connect(twoPreResReq1.y, swi2.u1);
connect(thrPreResReq1.y, swi1.u1);
connect(swi2.y,swi1. u3);
connect(THeaSet, sub1.u1);
connect(THeaSet, sub4.u1);
connect(TZon, sub1.u2);
connect(TZon, sub4.u2);
connect(uHea, greThr12.u);
connect(greThr12.y, lat.u);
connect(uHea, lesThr.u);
connect(lesThr.y, lat.clr);
connect(lat.y, booToInt6.u);
connect(booToInt6.y, yHeaFanReq);
connect(uHea, greThr5.u);
connect(greThr5.y, booToInt3.u);
connect(booToInt3.y, mulInt2.u2);
connect(swi1.y, mulInt2.u1);
connect(mulInt2.y, yHotDucPreResReq);
connect(uHea, greThr6.u);
connect(uCoo, greThr13.u);
connect(greThr13.y, or2.u1);
connect(greThr6.y, or2.u2);
connect(or2.y, not1.u);
connect(greThr13.y, or1.u1);
connect(not1.y, or1.u2);
connect(or1.y, booToInt2.u);
connect(swi4.y, mulInt1.u1);
connect(booToInt2.y, mulInt1.u2);
connect(mulInt1.y, yColDucPreResReq);
connect(greThr4.y, and10.u1);
connect(greEqu.y, and8.u2);
connect(greEqu1.y, and9.u2);
end SystemRequests;