Library logo

Buildings.Controls.OBC.ASHRAE.G36.TerminalUnits.Reheat.Subsequences

Package of subsequences for terminal unit with reheat

Information

This package contains subsequences for VAV terminal unit with reheat only unit. They are created according to Section 5.6 of ASHRAE Guideline 36, May 2020.

Package Content

Name Description
Buildings.Controls.OBC.ASHRAE.G36.TerminalUnits.Reheat.Subsequences.ActiveAirFlow ActiveAirFlow Output the active airflow setpoint for VAV reheat terminal unit
Buildings.Controls.OBC.ASHRAE.G36.TerminalUnits.Reheat.Subsequences.Alarms Alarms Generate alarms of terminal unit with reheat
Buildings.Controls.OBC.ASHRAE.G36.TerminalUnits.Reheat.Subsequences.DamperValves DamperValves Output signals for controlling VAV reheat box damper and valve position
Buildings.Controls.OBC.ASHRAE.G36.TerminalUnits.Reheat.Subsequences.Overrides Overrides Software switches to override setpoints
Buildings.Controls.OBC.ASHRAE.G36.TerminalUnits.Reheat.Subsequences.SystemRequests SystemRequests Output system requests for VAV terminal unit with reheat
Buildings.Controls.OBC.ASHRAE.G36.TerminalUnits.Reheat.Subsequences.Validation Validation Collection of validation models

Buildings.Controls.OBC.ASHRAE.G36.TerminalUnits.Reheat.Subsequences.ActiveAirFlow Buildings.Controls.OBC.ASHRAE.G36.TerminalUnits.Reheat.Subsequences.ActiveAirFlow

Output the active airflow setpoint for VAV reheat terminal unit

Buildings.Controls.OBC.ASHRAE.G36.TerminalUnits.Reheat.Subsequences.ActiveAirFlow

Information

This sequence sets the active cooling and heating maximum and minimum setpoints for VAV reheat terminal unit. The implementation is according to the Section 5.6.4 of ASHRAE Guideline 36, May 2020.

The setpoints shall vary depending on the mode of the zone group.

Setpoint OccupiedCooldown SetupWarm-upSetbackUnoccupied
Cooling maximum (VActCooMax_flow)VCooMax_flow VCooMax_flowVCooMax_flow 000
Cooling minimum (VActCooMin_flow)VOccMin_flow 00000
Minimum (VActMin_flow)VOccMin_flow0 0000
Heating minimum (VActHeaMin_flow)max(VHeaMin_flow,VOccMin_flow) VHeaMin_flow0VHeaMax_flowVHeaMax_flow 0
Heating maximum (VActHeaMax_flow)max(VHeaMax_flow,VOccMin_flow) VHeaMax_flow0VCooMax_flowVCooMax_flow 0

Parameters

TypeNameDefaultDescription
RealVCooMax_flow Design zone cooling maximum airflow rate [m3/s]
RealVHeaMin_flow Design zone heating minimum airflow rate, for the reheat box with water hot coil, it should be zero [m3/s]
RealVHeaMax_flow Design zone heating maximum airflow rate [m3/s]

Connectors

TypeNameDescription
input IntegerInputuOpeModZone operation mode
input RealInputVOccMin_flowOccupied minimum airflow setpoint [m3/s]
output RealOutputVActCooMax_flowActive cooling maximum airflow setpoint [m3/s]
output RealOutputVActCooMin_flowActive cooling minimum airflow setpoint [m3/s]
output RealOutputVActMin_flowActive minimum airflow setpoint [m3/s]
output RealOutputVActHeaMin_flowActive heating minimum airflow setpoint [m3/s]
output RealOutputVActHeaMax_flowActive heating maximum airflow setpoint [m3/s]

Modelica definition

block ActiveAirFlow "Output the active airflow setpoint for VAV reheat terminal unit" parameter Real VCooMax_flow( final quantity="VolumeFlowRate", final unit="m3/s") "Design zone cooling maximum airflow rate"; parameter Real VHeaMin_flow( final quantity="VolumeFlowRate", final unit="m3/s") "Design zone heating minimum airflow rate, for the reheat box with water hot coil, it should be zero"; parameter Real VHeaMax_flow( final quantity="VolumeFlowRate", final unit="m3/s") "Design zone heating maximum airflow rate"; Buildings.Controls.OBC.CDL.Interfaces.IntegerInput uOpeMod "Zone operation mode"; Buildings.Controls.OBC.CDL.Interfaces.RealInput VOccMin_flow( final unit="m3/s", final quantity="VolumeFlowRate") "Occupied minimum airflow setpoint"; 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 VActCooMin_flow( final min=0, final unit="m3/s", final quantity="VolumeFlowRate") "Active cooling minimum 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 VActHeaMin_flow( final min=0, final unit="m3/s", final quantity="VolumeFlowRate") "Active heating 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.Reals.Multiply pro "Active cooling minimum, minimum airflow setpoint"; Buildings.Controls.OBC.CDL.Reals.Max max1 "Maximum of inputs"; Buildings.Controls.OBC.CDL.Conversions.BooleanToReal heaMinFlo( final realTrue=VHeaMin_flow) "Heating minimum flow when input is true"; Buildings.Controls.OBC.CDL.Conversions.BooleanToReal heaMaxFlo( final realTrue=VHeaMax_flow) "Heating maximum flow when input is true"; Buildings.Controls.OBC.CDL.Conversions.BooleanToReal cooMaxFlo( final realTrue=VCooMax_flow) "Cooling maximum flow when input is true"; Buildings.Controls.OBC.CDL.Reals.Max max2 "Maximum of inputs"; Buildings.Controls.OBC.CDL.Reals.Multiply pro1 "Product of inputs"; Buildings.Controls.OBC.CDL.Logical.Or or2 "Check if it is warm-up or setback"; Buildings.Controls.OBC.CDL.Reals.Add add2 "Add up inputs"; Buildings.Controls.OBC.CDL.Reals.Add add1 "Active heating minimu flow setpoint"; Buildings.Controls.OBC.CDL.Reals.Multiply pro2 "Product of inputs"; Buildings.Controls.OBC.CDL.Conversions.BooleanToReal heaMaxFlo1( final realTrue=VHeaMax_flow) "Heating maximum flow when input is true"; Buildings.Controls.OBC.CDL.Reals.Add add3 "Add up inputs"; Buildings.Controls.OBC.CDL.Reals.Add add4 "Active heating maximum flow setpoint"; 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.Reals.Sources.Constant heaMaxAir( final k=VHeaMax_flow) "Heating maximum airflow"; Buildings.Controls.OBC.CDL.Reals.Sources.Constant heaMinAir( final k=VHeaMin_flow) "Heating minimum airflow"; 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(VOccMin_flow, max1.u1); connect(heaMinAir.y, max1.u2); connect(VOccMin_flow, max2.u1); connect(heaMaxAir.y, max2.u2); connect(max1.y, pro1.u2); connect(occModInd.y, pro1.u1); connect(ifCooDow.y, heaMinFlo.u); connect(ifWarUp.y, or2.u1); connect(or2.y, heaMaxFlo.u); connect(ifSetBac.y, or2.u2); connect(heaMinFlo.y, add2.u1); connect(heaMaxFlo.y, add2.u2); connect(pro1.y, add1.u1); connect(add2.y, add1.u2); connect(max2.y, pro2.u2); connect(occModInd.y, pro2.u1); connect(or2.y, cooMaxFlo.u); connect(ifCooDow.y, heaMaxFlo1.u); connect(heaMaxFlo1.y, add3.u2); connect(cooMaxFlo.y, add3.u1); connect(pro2.y, add4.u1); connect(add3.y, add4.u2); connect(actCooMax.y, VActCooMax_flow); connect(pro.y, VActCooMin_flow); connect(pro.y, VActMin_flow); connect(add1.y, VActHeaMin_flow); connect(add4.y, VActHeaMax_flow); end ActiveAirFlow;

Buildings.Controls.OBC.ASHRAE.G36.TerminalUnits.Reheat.Subsequences.Alarms Buildings.Controls.OBC.ASHRAE.G36.TerminalUnits.Reheat.Subsequences.Alarms

Generate alarms of terminal unit with reheat

Buildings.Controls.OBC.ASHRAE.G36.TerminalUnits.Reheat.Subsequences.Alarms

Information

This block outputs alarms of terminal unit with reheat. The implementation is according to the Section 5.6.6 of ASHRAE Guideline 36, May 2020.

Low airflow

  1. If the zone is in occupied mode and after the AHU supply fan has been enabled for staTim, if the measured airflow VDis_flow is less than 70% of setpoint VActSet_flow for 5 minutes (lowFloTim) while the setpoint is greater than zero, generate a Level 3 alarm.
  2. If the zone is in occupied mode and after the AHU supply fan has been enabled for staTim, if the measured airflow VDis_flow is less than 50% of setpoint VActSet_flow for 5 minutes (lowFloTim) while the setpoint is greater than zero, generate a Level 2 alarm.
  3. 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.

Low-discharging air temperature

  1. If the zone is in occupied mode and if heating hot-water plant is proven on (u1HotPla=true), and the discharge temperature (TDis) is 8 °C (15 °F) less than the setpoint (TDisSet) for 10 minuts (lowTemTim), generate a Level 3 alarm.
  2. If the zone is in occupied mode and if heating hot-water plant is proven on (u1HotPla=true), and the discharge temperature (TDis) is 17 °C (30 °F) less than the setpoint (TDisSet) for 10 minuts (lowTemTim), generate a Level 2 alarm.
  3. If a zone has an importance multiplier (hotWatRes) of 0 for its hot-water reset Trim-Respond control loop, low discharing air temperature alarms shall be suppressed for that zone.

Airflow sensor calibration

If the fan serving the zone has been OFF (u1Fan=false) for 10 minutes (fanOffTim), and airflow sensor reading VDis_flow is above 10% of the cooling maximum airflow setpoint VCooMax_flow, generate a Level 3 alarm.

Leaking damper

If the damper position (uDam) is 0% and airflow sensor reading VDis_flow is above 10% of the cooling maximum airflow setpoint VCooMax_flow for 10 minutes (leaFloTim) while the fan serving the zone is proven on (u1Fan=true), generate a Level 4 alarm.

Leaking valve

If the valve position (uVal) is 0% for 15 minutes (valCloTim), discharing air temperature TDis is above AHU supply temperature TSup by 3 °C (5 °F), and the fan serving the zone is proven on (u1Fan=true), gemerate a Level 4 alarm.

Parameters

TypeNameDefaultDescription
Booleanhave_hotWatCoi True: the unit has the hot water coil
RealstaPreMul Importance multiplier for the zone static pressure reset control loop
RealhotWatRes Importance multiplier for the hot water reset control loop
RealVCooMax_flow Design zone cooling maximum airflow rate [m3/s]
ReallowFloTim300Threshold time to check low flow rate [s]
ReallowTemTim600Threshold time to check low discharge temperature [s]
RealfanOffTim600Threshold time to check fan off [s]
RealleaFloTim600Threshold time to check damper leaking airflow [s]
RealvalCloTim900Threshold time to check valve leaking water flow [s]
Advanced
RealfloHys0.05Near zero flow rate, below which the flow rate or difference will be seen as zero [m3/s]
RealdTHys0.25Temperature difference hysteresis below which the temperature difference will be seen as zero [K]
RealdamPosHys0.05Near zero damper position, below which the damper will be seen as closed [1]
RealvalPosHys0.05Near zero valve position, below which the valve will be seen as closed [1]
RealstaTim1800Delay triggering alarms after enabling AHU supply fan [s]

Connectors

TypeNameDescription
input RealInputVDis_flowMeasured discharge airflow rate airflow rate [m3/s]
input RealInputVActSet_flowActive airflow setpoint [m3/s]
input BooleanInputu1FanAHU supply fan status
input IntegerInputuOpeModZone operation mode
input RealInputuDamDamper position setpoint [1]
input RealInputuValActual valve position [1]
input RealInputTSupAir handler supply air temperature [K]
input BooleanInputu1HotPlaHot water plant status
input RealInputTDisMeasured discharge air temperature [K]
input RealInputTDisSetDischarge air temperature setpoint [K]
output IntegerOutputyLowFloAlaLow airflow alarms
output IntegerOutputyFloSenAlaAirflow sensor calibration alarm
output IntegerOutputyLeaDamAlaLeaking damper alarm
output IntegerOutputyLeaValAlaLeaking valve alarm
output IntegerOutputyLowTemAlaLow discharge air temperature alarms

Modelica definition

block Alarms "Generate alarms of terminal unit with reheat" parameter Boolean have_hotWatCoi "True: the unit has the hot water coil"; parameter Real staPreMul "Importance multiplier for the zone static pressure reset control loop"; parameter Real hotWatRes "Importance multiplier for the hot water 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 lowTemTim( final unit="s", final quantity="Time")=600 "Threshold time to check low discharge temperature"; 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 valCloTim( final unit="s", final quantity="Time")=900 "Threshold time to check valve leaking water flow"; 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 dTHys( final unit="K", final quantity="TemperatureDifference")=0.25 "Temperature difference hysteresis below which the temperature 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"; parameter Real valPosHys( final unit="1")=0.05 "Near zero valve position, below which the valve will be seen as closed"; parameter Real staTim( final unit="s", final quantity="Time")=1800 "Delay triggering alarms after enabling AHU supply fan"; Buildings.Controls.OBC.CDL.Interfaces.RealInput VDis_flow( final min=0, final unit="m3/s", final quantity="VolumeFlowRate") "Measured discharge airflow rate 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 u1Fan "AHU supply fan status"; Buildings.Controls.OBC.CDL.Interfaces.IntegerInput uOpeMod "Zone operation mode"; Buildings.Controls.OBC.CDL.Interfaces.RealInput uDam( final min=0, final unit="1") "Damper position setpoint"; Buildings.Controls.OBC.CDL.Interfaces.RealInput uVal( final min=0, final unit="1") "Actual valve position"; Buildings.Controls.OBC.CDL.Interfaces.RealInput TSup( final unit="K", final displayUnit="degC", final quantity="ThermodynamicTemperature") "Air handler supply air temperature"; Buildings.Controls.OBC.CDL.Interfaces.BooleanInput u1HotPla if have_hotWatCoi "Hot water plant status"; 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.RealInput TDisSet( final unit="K", final displayUnit="degC", final quantity="ThermodynamicTemperature") if have_hotWatCoi "Discharge air temperature 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 damper alarm"; Buildings.Controls.OBC.CDL.Interfaces.IntegerOutput yLeaValAla "Leaking valve alarm"; Buildings.Controls.OBC.CDL.Interfaces.IntegerOutput yLowTemAla if have_hotWatCoi "Low discharge air temperature alarms"; Buildings.Controls.OBC.CDL.Reals.MultiplyByParameter gai( final k=0.5) "Percentage of the setpoint"; Buildings.Controls.OBC.CDL.Reals.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.Reals.GreaterThreshold greThr(t=floHys, final h=0.5*floHys) "Check if setpoint airflow is greater than zero"; Buildings.Controls.OBC.CDL.Reals.Greater gre( final h=floHys) "Check if measured airflow is less than threshold"; Buildings.Controls.OBC.CDL.Reals.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.Reals.Sources.Constant conInt1( final k=staPreMul) "Importance multiplier for zone static pressure reset"; Buildings.Controls.OBC.CDL.Reals.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 and4 "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 and12 "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.Reals.Sources.Constant cooMaxFlo( final k=VCooMax_flow) "Cooling maximum airflow setpoint"; Buildings.Controls.OBC.CDL.Reals.MultiplyByParameter gai2( final k=0.1) "Percentage of the setpoint"; Buildings.Controls.OBC.CDL.Logical.Not not3 "Logical not"; Buildings.Controls.OBC.CDL.Logical.TrueDelay truDel2( final delayTime=fanOffTim) "Check if the supply fan has been OFF more than threshold time"; Buildings.Controls.OBC.CDL.Reals.Greater gre1( final h=floHys) "Check if measured airflow is greater than threshold"; Buildings.Controls.OBC.CDL.Logical.And and5 "Logical and"; Buildings.Controls.OBC.CDL.Logical.Not not4 "Logical not"; Buildings.Controls.OBC.CDL.Utilities.Assert assMes2( final message="Warning: airflow sensor should be calibrated.") "Level 3 airflow sensor alarm"; Buildings.Controls.OBC.CDL.Conversions.BooleanToInteger booToInt2( final integerTrue=3) "Convert boolean true to level 3 alarm"; Buildings.Controls.OBC.CDL.Logical.TrueDelay truDel3( final delayTime=leaFloTim) "Check if the air flow is above threshold by more than threshold time"; Buildings.Controls.OBC.CDL.Reals.LessThreshold cloDam( final t=damPosHys, final h=0.5*damPosHys) "Check if damper position is near zero"; Buildings.Controls.OBC.CDL.Logical.And leaDamAla "Check if generating leak damper alarms"; Buildings.Controls.OBC.CDL.Logical.Not not5 "Logical not"; Buildings.Controls.OBC.CDL.Utilities.Assert assMes3( final message="Warning: the damper is leaking.") "Level 4 leaking damper alarm"; Buildings.Controls.OBC.CDL.Conversions.BooleanToInteger booToInt3( final integerTrue=4) "Convert boolean true to level 4 alarm"; Buildings.Controls.OBC.CDL.Reals.Less les1( final h=dTHys) if have_hotWatCoi "Discharge temperature lower than setpoint by a threshold"; Buildings.Controls.OBC.CDL.Reals.AddParameter addPar( final p=-17) if have_hotWatCoi "Setpoint temperature minus a threshold"; Buildings.Controls.OBC.CDL.Reals.Less les2( final h=dTHys) if have_hotWatCoi "Discharge temperature lower than setpoint by a threshold"; Buildings.Controls.OBC.CDL.Reals.AddParameter addPar1( final p=-8) if have_hotWatCoi "Setpoint temperature minus a threshold"; Buildings.Controls.OBC.CDL.Logical.TrueDelay truDel4( final delayTime=lowTemTim) if have_hotWatCoi "Check if the discharge temperature has been less than threshold value for threshold time"; Buildings.Controls.OBC.CDL.Logical.TrueDelay truDel5( final delayTime=lowTemTim) if have_hotWatCoi "Check if the discharge temperature has been less than threshold value for threshold time"; Buildings.Controls.OBC.CDL.Logical.And and6 if have_hotWatCoi "Discharge temperature has been less than threshold value for sufficient time"; Buildings.Controls.OBC.CDL.Logical.And and7 if have_hotWatCoi "Logical and"; Buildings.Controls.OBC.CDL.Logical.Not not6 if have_hotWatCoi "Logical not"; Buildings.Controls.OBC.CDL.Utilities.Assert assMes4( final message="Warning: discharge air temperature is 17 degC less than the setpoint.") if have_hotWatCoi "Level 2 low discharge air temperature alarm"; Buildings.Controls.OBC.CDL.Integers.Switch lowTemAla if have_hotWatCoi "Low discharge temperature alarm"; Buildings.Controls.OBC.CDL.Integers.Sources.Constant conInt2( final k=2) if have_hotWatCoi "Level 2 alarm"; Buildings.Controls.OBC.CDL.Logical.And and8 if have_hotWatCoi "Discharge temperature has been less than threshold value for sufficient time"; Buildings.Controls.OBC.CDL.Conversions.BooleanToInteger booToInt4( final integerTrue=3) if have_hotWatCoi "Convert boolean true to level 3 alarm"; Buildings.Controls.OBC.CDL.Logical.And and9 if have_hotWatCoi "Logical and"; Buildings.Controls.OBC.CDL.Logical.Not not7 if have_hotWatCoi "Logical not"; Buildings.Controls.OBC.CDL.Utilities.Assert assMes5( final message="Warning: discharge air temperature is 8 degC less than the setpoint.") if have_hotWatCoi "Level 3 low airflow alarm"; Buildings.Controls.OBC.CDL.Reals.Sources.Constant conInt3( final k=hotWatRes) if have_hotWatCoi "Importance multiplier for hot water reset control"; Buildings.Controls.OBC.CDL.Reals.GreaterThreshold greThr2 if have_hotWatCoi "Check if the multiplier is greater than zero"; Buildings.Controls.OBC.CDL.Conversions.BooleanToInteger booToInt5 if have_hotWatCoi "Suppress the alarm when multiplier is zero"; Buildings.Controls.OBC.CDL.Integers.Multiply proInt1 if have_hotWatCoi "Low discharge air temperature alarms"; Buildings.Controls.OBC.CDL.Logical.TrueDelay truDel6( final delayTime=valCloTim) "Check if valve position is closed for more than threshold time"; Buildings.Controls.OBC.CDL.Reals.LessThreshold cloVal( final t=valPosHys, final h=0.5*valPosHys) "Check if valve position is near zero"; Buildings.Controls.OBC.CDL.Reals.AddParameter addPar2( final p=3) "AHU supply temperature plus 3 degree"; Buildings.Controls.OBC.CDL.Reals.Greater gre2( final h=dTHys) "Discharge temperature greate than AHU supply temperature by a threshold"; Buildings.Controls.OBC.CDL.Logical.And leaValAla "Check if generating leak valve alarms"; Buildings.Controls.OBC.CDL.Conversions.BooleanToInteger booToInt6( final integerTrue=4) "Convert boolean true to level 4 alarm"; Buildings.Controls.OBC.CDL.Logical.Not not8 "Logical not"; Buildings.Controls.OBC.CDL.Utilities.Assert assMes6( final message="Warning: the valve is leaking.") "Level 4 leaking valve alarm"; Buildings.Controls.OBC.CDL.Logical.TrueDelay truDel7( final delayTime=lowFloTim) "Check if the active flow setpoint has been greater than zero for the threshold time"; Buildings.Controls.OBC.CDL.Logical.And fanHotPlaOn if have_hotWatCoi "True: both the supply fan and the hot water plant are ON"; Buildings.Controls.OBC.CDL.Logical.And and10 "True: AHU fan is enabled and the discharge flow is lower than the threshold"; Buildings.Controls.OBC.CDL.Logical.And and11 "True: AHU fan is enabled and the discharge flow is lower than the threshold"; Buildings.Controls.OBC.CDL.Logical.TrueDelay fanIni( final delayTime=staTim) "Check if the AHU supply fan has been enabled for threshold time"; Buildings.Controls.OBC.CDL.Integers.Equal isOcc "Check if current operation mode is occupied mode"; Buildings.Controls.OBC.CDL.Integers.Sources.Constant occMod( final k=Buildings.Controls.OBC.ASHRAE.G36.Types.OperationModes.occupied) "Occupied mode"; Buildings.Controls.OBC.CDL.Logical.And and3 "Logical and"; Buildings.Controls.OBC.CDL.Logical.And and13 "Logical and"; Buildings.Controls.OBC.CDL.Logical.And leaDamAla1 "Check if generating leak damper alarms"; Buildings.Controls.OBC.CDL.Logical.And leaValAla1 "Check if generating leak valve alarms"; Buildings.Controls.OBC.CDL.Logical.And and14 if have_hotWatCoi "Logical and"; Buildings.Controls.OBC.CDL.Logical.And and15 if have_hotWatCoi "Logical and"; equation connect(VActSet_flow, gai.u); connect(VDis_flow, les.u1); connect(VActSet_flow, greThr.u); connect(VActSet_flow, gai1.u); connect(VDis_flow, gre.u2); connect(gai1.y, gre.u1); connect(truDel.y, and2.u1); connect(truDel1.y, and1.u2); connect(conInt.y, lowFloAla.u1); 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(and2.y,and4. u1); connect(greThr1.y,and4. u2); connect(and1.y, and12.u1); connect(greThr1.y, and12.u2); connect(not2.y, assMes1.u); connect(cooMaxFlo.y, gai2.u); connect(u1Fan, not3.u); connect(gai2.y, gre1.u2); connect(gre1.y, and5.u1); connect(not4.y, assMes2.u); connect(booToInt2.y, yFloSenAla); connect(proInt.y, yLowFloAla); connect(uDam, cloDam.u); connect(u1Fan, leaDamAla.u2); connect(not5.y, assMes3.u); connect(booToInt3.y, yLeaDamAla); connect(VDis_flow, gre1.u1); connect(TDis, les1.u1); connect(TDisSet, addPar.u); connect(addPar.y, les1.u2); connect(TDis, les2.u1); connect(TDisSet, addPar1.u); connect(addPar1.y, les2.u2); connect(les1.y, truDel4.u); connect(les2.y, truDel5.u); connect(truDel4.y, and6.u1); connect(conInt2.y, lowTemAla.u1); connect(not6.y, assMes4.u); connect(truDel5.y, and8.u1); connect(and8.y, and9.u1); connect(booToInt4.y, lowTemAla.u3); connect(not7.y, assMes5.u); connect(conInt3.y, greThr2.u); connect(greThr2.y, booToInt5.u); connect(lowTemAla.y, proInt1.u1); connect(booToInt5.y, proInt1.u2); connect(greThr2.y, and7.u2); connect(greThr2.y, and9.u2); connect(proInt1.y, yLowTemAla); connect(uVal, cloVal.u); connect(TSup, addPar2.u); connect(TDis, gre2.u1); connect(addPar2.y, gre2.u2); connect(not8.y, assMes6.u); connect(booToInt6.y, yLeaValAla); connect(greThr.y, truDel7.u); connect(truDel7.y, and1.u1); connect(truDel7.y, and2.u2); connect(u1HotPla, fanHotPlaOn.u1); connect(fanHotPlaOn.y, and6.u2); connect(fanHotPlaOn.y, and8.u2); connect(u1Fan, fanHotPlaOn.u2); connect(gre1.y, leaDamAla.u1); connect(not3.y, and5.u2); connect(and5.y, truDel2.u); connect(cloVal.y, leaValAla.u1); connect(u1Fan, leaValAla.u2); connect(les.y, and10.u1); connect(and10.y, truDel.u); connect(gre.y, and11.u1); connect(and11.y, truDel1.u); connect(u1Fan, fanIni.u); connect(fanIni.y, and11.u2); connect(fanIni.y, and10.u2); connect(uOpeMod, isOcc.u1); connect(occMod.y, isOcc.u2); connect(and6.y, and7.u1); connect(truDel3.y, booToInt3.u); connect(truDel3.y, not5.u); connect(truDel6.y, booToInt6.u); connect(truDel6.y, not8.u); connect(truDel2.y, booToInt2.u); connect(truDel2.y, not4.u); connect(gai.y, les.u2); connect(and4.y, and13.u1); connect(and12.y, and3.u1); connect(and3.y, booToInt.u); connect(and13.y, lowFloAla.u2); connect(and13.y, not1.u); connect(and3.y, not2.u); connect(isOcc.y, and13.u2); connect(isOcc.y, and3.u2); connect(leaDamAla.y, leaDamAla1.u1); connect(leaDamAla1.y, truDel3.u); connect(leaValAla.y, leaValAla1.u1); connect(leaValAla1.y, truDel6.u); connect(cloDam.y, leaDamAla1.u2); connect(gre2.y, leaValAla1.u2); connect(and7.y, and15.u1); connect(and9.y, and14.u1); connect(and14.y, booToInt4.u); connect(and15.y, lowTemAla.u2); connect(isOcc.y, and15.u2); connect(isOcc.y, and14.u2); connect(and15.y, not6.u); connect(and14.y, not7.u); end Alarms;

Buildings.Controls.OBC.ASHRAE.G36.TerminalUnits.Reheat.Subsequences.DamperValves Buildings.Controls.OBC.ASHRAE.G36.TerminalUnits.Reheat.Subsequences.DamperValves

Output signals for controlling VAV reheat box damper and valve position

Buildings.Controls.OBC.ASHRAE.G36.TerminalUnits.Reheat.Subsequences.DamperValves

Information

This sequence sets the damper and valve position for VAV reheat terminal unit. The implementation is according to Section 5.6.5 of ASHRAE Guideline 36, May 2020. The calculation is done following the steps below.

  1. When the zone state is cooling (uCoo > 0), then the cooling loop output uCoo shall be mapped to the airflow setpoint from the cooling minimum VActCooMin_flow to the cooling maximum VActCooMax_flow airflow setpoints. The heating coil is disabled (yVal=0) unless the discharge air temperature TDis is below the minimum setpoint (10 °C).
    • If supply air temperature TSup from the AHU is greater than room temperature TZon, cooling supply airflow setpoint shall be no higher than the minimum.
  2. When the zone state is Deadband (uCoo=0 and uHea=0), then the active airflow setpoint shall be the minimum airflow setpoint VActMin_flow. The heating coil is disabled unless the discharge air temperature is below the minimum setpoint (10 °C).
  3. When the zone state is Heating (uHea > 0), then the heating loop shall maintain space temperature at the heating setpoint as follows:
    • From 0% to 50%, the heating loop output uHea shall reset the discharge temperature setpoint from current AHU SAT setpoint TSupSet to a maximum of dTDisZonSetMax above space temperature setpoint. The airflow setpoint shall be the heating minimum VActHeaMin_flow.
    • From 50% to 100%, if the discharge air temperature TDis is greater than room temperature plus 3 Kelvin, the heating loop output uHea shall reset the airflow setpoint from the heating minimum airflow setpoint VActHeaMin_flow to the heating maximum airflow setpoint VActHeaMax_flow.
    • The heating coil shall be modulated to maintain the discharge temperature at setpoint.
  4. The VAV damper shall be modulated by a control loop to maintain the measured airflow at the active setpoint.
  5. In occupied mode, the heating coil shall be modulated a discharge temperature no lower than 10 °C (50 °F).

The sequences of controlling damper and valve position for VAV reheat terminal unit are described in the following figure below.

Image of damper and valve control for VAV reheat terminal unit

As specified in Section 5.6.7 of ASHRAE Guideline 36, the airflow setpoint could be override by providing software switches that interlock to a system-level point to:

  1. when oveFloSet equals to 1, force the zone airflow setpoint VSet_flow to zero,
  2. when oveFloSet equals to 2, force the zone airflow setpoint VSet_flow to zone cooling maximum airflow rate VCooMax_flow,
  3. when oveFloSet equals to 3, force the zone airflow setpoint VSet_flow to zone minimum airflow setpoint VMin_flow.
  4. when oveFloSet equals to 4, force the zone airflow setpoint VSet_flow to zone heating maximum airflow setpoint VHeaMax_flow.

Parameters

TypeNameDefaultDescription
RealdTDisZonSetMax11Zone maximum discharge air temperature above heating setpoint [K]
RealTDisMin283.15Lowest discharge air temperature [K]
RealVMin_flow Design zone minimum airflow setpoint [m3/s]
RealVCooMax_flow Design zone cooling maximum airflow rate [m3/s]
RealVHeaMax_flow Design zone heating maximum airflow rate [m3/s]
Valve
SimpleControllercontrollerTypeValBuildings.Controls.OBC.CDL.T...Type of controller
RealkVal0.5Gain of controller for valve control [1/K]
RealTiVal300Time constant of integrator block for valve control [s]
RealTdVal0.1Time constant of derivative block for valve control [s]
Damper
SimpleControllercontrollerTypeDamBuildings.Controls.OBC.CDL.T...Type of controller
RealkDam0.5Gain of controller for damper control [1]
RealTiDam300Time constant of integrator block for damper control [s]
RealTdDam0.1Time constant of derivative block for damper control [s]
Advanced
RealdTHys0.25Temperature difference hysteresis below which the temperature difference will be seen as zero [K]
ReallooHys0.01Loop output hysteresis below which the output will be seen as zero [1]
RealiniDam0.01Initial damper position when the damper control is enabled [1]

Connectors

TypeNameDescription
input IntegerInputoveFloSetIndex of overriding flow setpoint, 1: set to zero; 2: set to cooling maximum; 3: set to minimum flow; 4: set to heating maximum
input RealInputVDis_flowMeasured primary discharge airflow rate [m3/s]
input RealInputVActCooMin_flowActive cooling minimum airflow rate [m3/s]
input RealInputuCooCooling control signal [1]
input RealInputVActCooMax_flowActive cooling maximum airflow rate [m3/s]
input RealInputTSupTemperature of the air supplied from central air handler [K]
input RealInputVActMin_flowActive minimum airflow rate [m3/s]
input BooleanInputu1FanAHU supply fan status
input RealInputTDisMeasured discharge air temperature [K]
input RealInputTSupSetSupply air temperature setpoint from central air handler [K]
input RealInputTHeaSetZone heating setpoint temperature [K]
input RealInputuHeaHeating control signal [1]
input RealInputTZonMeasured zone temperature [K]
input RealInputVActHeaMin_flowActive heating minimum airflow rate [m3/s]
input RealInputVActHeaMax_flowActive heating maximum airflow rate [m3/s]
input IntegerInputuOpeModZone operation mode
output RealOutputVSet_flowCommanded discharge airflow setpoint [m3/s]
output RealOutputyDamVAV damper commanded position [1]
output RealOutputyValReheater valve commanded position [1]
output RealOutputTDisSetDischarge airflow setpoint temperature [K]

Modelica definition

block DamperValves "Output signals for controlling VAV reheat box damper and valve position" parameter Real dTDisZonSetMax(unit="K")=11 "Zone maximum discharge air temperature above heating setpoint"; parameter Real TDisMin( unit="K", displayUnit="degC")=283.15 "Lowest discharge air temperature"; parameter Real VMin_flow(unit="m3/s") "Design zone minimum airflow setpoint"; parameter Real VCooMax_flow(unit="m3/s") "Design zone cooling maximum airflow rate"; parameter Real VHeaMax_flow(unit="m3/s") "Design zone heating maximum airflow rate"; parameter Buildings.Controls.OBC.CDL.Types.SimpleController controllerTypeVal= Buildings.Controls.OBC.CDL.Types.SimpleController.PI "Type of controller"; parameter Real kVal(unit="1/K")=0.5 "Gain of controller for valve control"; parameter Real TiVal(unit="s")=300 "Time constant of integrator block for valve control"; parameter Real TdVal(unit="s")=0.1 "Time constant of derivative block for valve control"; parameter Buildings.Controls.OBC.CDL.Types.SimpleController controllerTypeDam= Buildings.Controls.OBC.CDL.Types.SimpleController.PI "Type of controller"; parameter Real kDam(unit="1")=0.5 "Gain of controller for damper control"; parameter Real TiDam(unit="s")=300 "Time constant of integrator block for damper control"; parameter Real TdDam(unit="s")=0.1 "Time constant of derivative block for damper control"; parameter Real dTHys(unit="K")=0.25 "Temperature difference hysteresis below which the temperature difference will be seen as zero"; parameter Real looHys(unit="1")=0.01 "Loop output hysteresis below which the output will be seen as zero"; parameter Real iniDam(unit="1")=0.01 "Initial damper position when the damper control is enabled"; 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 VDis_flow( final min=0, final unit="m3/s", final quantity="VolumeFlowRate") "Measured primary discharge airflow rate"; Buildings.Controls.OBC.CDL.Interfaces.RealInput VActCooMin_flow( final min=0, final unit="m3/s", final quantity="VolumeFlowRate") "Active cooling minimum airflow rate"; 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 TSup( final unit="K", final displayUnit="degC", final quantity="ThermodynamicTemperature") "Temperature of the air supplied from central air handler"; 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.BooleanInput u1Fan "AHU supply fan status"; 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.RealInput TSupSet( final unit="K", final displayUnit="degC", final quantity="ThermodynamicTemperature") "Supply air temperature setpoint from central air handler"; 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 control signal"; 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 VActHeaMin_flow( final min=0, final unit="m3/s", final quantity="VolumeFlowRate") "Active heating minimum airflow rate"; 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.IntegerInput uOpeMod "Zone operation mode"; Buildings.Controls.OBC.CDL.Interfaces.RealOutput VSet_flow( final min=0, final unit="m3/s", final quantity="VolumeFlowRate") "Commanded discharge airflow setpoint"; Buildings.Controls.OBC.CDL.Interfaces.RealOutput yDam( final min=0, final max=1, final unit="1") "VAV damper commanded position"; Buildings.Controls.OBC.CDL.Interfaces.RealOutput yVal( final min=0, final max=1, final unit="1") "Reheater valve commanded position"; Buildings.Controls.OBC.CDL.Interfaces.RealOutput TDisSet( final unit="K", final displayUnit="degC", final quantity="ThermodynamicTemperature") "Discharge airflow setpoint temperature"; Buildings.Controls.OBC.CDL.Logical.And and4 "Logical and"; Buildings.Controls.OBC.CDL.Reals.Line lin "Active airflow setpoint for cooling"; Buildings.Controls.OBC.CDL.Reals.PIDWithReset conDam( final controllerType=controllerTypeDam, final k=kDam, final Ti=TiDam, final Td=TdDam, final yMax=1, final yMin=0, final y_reset=iniDam) "Damper position controller"; Buildings.Controls.OBC.CDL.Reals.Switch swi "Output active cooling airflow according to cooling control signal"; Buildings.Controls.OBC.CDL.Reals.Switch swi5 "Airflow setpoint when it is in cooling state"; Buildings.Controls.OBC.CDL.Logical.Not not1 "Not in cooling state"; Buildings.Controls.OBC.CDL.Logical.Not not2 "Not in heating state"; Buildings.Controls.OBC.CDL.Logical.And and2 "Check if current zone state is deadband"; Buildings.Controls.OBC.CDL.Reals.Switch swi1 "Airflow setpoint when it is in deadband state"; Buildings.Controls.OBC.CDL.Reals.Line lin3 "Airflow setpoint when it is in heating state"; Buildings.Controls.OBC.CDL.Reals.Switch swi2 "Acitive heating airflow rate"; Buildings.Controls.OBC.CDL.Reals.Greater gre( final h=dTHys) "Check if the discharge air temperature is greater than zone temperature by a threshold"; Buildings.Controls.OBC.CDL.Reals.Line conTDisHeaSet "Discharge air temperature for heating"; Buildings.Controls.OBC.CDL.Logical.Or or2 "Enable heating coil when it is in heating state, or the discharge air temperature is lower than minimum"; Buildings.Controls.OBC.CDL.Reals.Switch swi3 "Discharge airflow setpoint when heating coil is enabled"; Buildings.Controls.OBC.CDL.Reals.PIDWithReset conVal( final controllerType=controllerTypeVal, final k=kVal, final Ti=TiVal, final Td=TdVal, final yMax=1, final yMin=0, u_s(final unit="K", displayUnit="degC"), u_m(final unit="K", displayUnit="degC")) "Hot water valve controller"; Buildings.Controls.OBC.CDL.Logical.And and1 "Occupied mode and discharge temperature is low"; Buildings.Controls.OBC.CDL.Reals.Sources.Constant conZer( final k=0) "Constant zero"; Buildings.Controls.OBC.CDL.Reals.Sources.Constant conOne( final k=1) "Constant one"; Buildings.Controls.OBC.CDL.Reals.GreaterThreshold greThr1( final t=looHys, final h=0.5*looHys) "Check if it is cooling state"; Buildings.Controls.OBC.CDL.Reals.GreaterThreshold greThr( final t=dTHys, final h=0.5*dTHys) "Check if supply air temperature is greater than room temperature"; Buildings.Controls.OBC.CDL.Reals.Subtract sub2 "Calculate temperature difference between AHU supply air and room "; Buildings.Controls.OBC.CDL.Reals.Switch watValPosUno "Output hot water valve position"; Buildings.Controls.OBC.CDL.Reals.Switch damPosUno "Output damper position"; Buildings.Controls.OBC.CDL.Reals.Divide VDis_flowNor "Normalized discharge volume flow rate"; Buildings.Controls.OBC.CDL.Reals.Divide VDisSet_flowNor "Normalized setpoint for discharge volume flow rate"; Buildings.Controls.OBC.CDL.Reals.LessThreshold lowMin( final t=TDisMin, final h=dTHys) "Check if discharge air temperature is less than lowest discharge air temperature"; Buildings.Controls.OBC.CDL.Reals.Sources.Constant conZer2( final k=0) "Constant zero"; Buildings.Controls.OBC.CDL.Reals.GreaterThreshold greThr2( final t=looHys, final h=0.8*looHys) "Check if it is heating state"; Buildings.Controls.OBC.CDL.Reals.Sources.Constant conHal1( final k=0.5) "Constant real value"; Buildings.Controls.OBC.CDL.Reals.Sources.Constant conOne2( final k=1) "Constant real value"; Buildings.Controls.OBC.CDL.Reals.AddParameter addPar1( final p=3) "Zone temperature plus threshold difference"; Buildings.Controls.OBC.CDL.Reals.Sources.Constant conHal( final k=0.5) "Constant real value"; Buildings.Controls.OBC.CDL.Reals.Sources.Constant conZer3( final k=0) "Constant zero"; Buildings.Controls.OBC.CDL.Reals.AddParameter addPar( final p=dTDisZonSetMax) "Maximum heating discharge temperature"; Buildings.Controls.OBC.CDL.Reals.Sources.Constant lowDisAirTem( final k=TDisMin) "Lowest allowed discharge air temperature"; Buildings.Controls.OBC.CDL.Reals.Switch swi4 "Output hot water valve position in case of low discharge air temperature"; Buildings.Controls.OBC.CDL.Integers.Sources.Constant occMod( final k=Buildings.Controls.OBC.ASHRAE.G36.Types.OperationModes.occupied) "Constant signal for occupied mode"; Buildings.Controls.OBC.CDL.Integers.Equal isOcc "Output true if the operation mode is occupied"; Buildings.Controls.OBC.CDL.Integers.Sources.Constant unOcc( final k=Buildings.Controls.OBC.ASHRAE.G36.Types.OperationModes.unoccupied) "Constant signal for unoccupied mode"; Buildings.Controls.OBC.CDL.Integers.Equal isUno "Output true if the operation mode is unoccupied"; Buildings.Controls.OBC.CDL.Reals.Max max1 "Ensure the discharge temperature being higher than the minimum"; 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.Reals.Add add2 "Add up two inputs"; Buildings.Controls.OBC.CDL.Reals.Add add1 "Add up inputs"; Buildings.Controls.OBC.CDL.Reals.Switch swi6 "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 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.Reals.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.Reals.Sources.Constant cooMax1( final k=VCooMax_flow) "Cooling maximum flow"; Buildings.Controls.OBC.CDL.Reals.Sources.Constant heaMax1( final k=VHeaMax_flow) "Heating maximum flow"; Buildings.Controls.OBC.CDL.Reals.Max max2 "Nominal flow"; Buildings.Controls.OBC.CDL.Logical.TrueFalseHold truFalHol( final trueHoldDuration=600, final falseHoldDuration=0) "Hold true input for certain time"; Buildings.Controls.OBC.CDL.Logical.TrueFalseHold truFalHol1( final trueHoldDuration=600, final falseHoldDuration=0) "Hold true input for certain time"; equation connect(uCoo, lin.u); connect(conZer.y, lin.x1); connect(VActCooMin_flow, lin.f1); 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(TSup, sub2.u1); connect(TZon, sub2.u2); connect(sub2.y, greThr.u); connect(greThr.y, and4.u2); connect(watValPosUno.y,yVal); connect(conDam.y, damPosUno.u3); connect(damPosUno.y, yDam); connect(VDis_flow, VDis_flowNor.u1); connect(VDis_flowNor.y, conDam.u_m); connect(VDisSet_flowNor.y, conDam.u_s); connect(VActMin_flow, swi5.u1); connect(TDis, lowMin.u); connect(uHea, greThr2.u); connect(not1.y, and2.u1); connect(not2.y, and2.u2); connect(and2.y, swi1.u2); connect(VActMin_flow, swi1.u1); connect(conHal1.y, lin3.x1); connect(VActHeaMin_flow, lin3.f1); connect(conOne2.y, lin3.x2); connect(VActHeaMax_flow, lin3.f2); connect(uHea, lin3.u); connect(TZon, addPar1.u); connect(TDis, gre.u1); connect(addPar1.y, gre.u2); connect(gre.y, swi2.u2); connect(VActHeaMin_flow, swi2.u3); connect(lin3.y, swi2.u1); connect(swi2.y, swi1.u3); connect(swi1.y, swi.u3); connect(THeaSet, addPar.u); connect(conZer3.y, conTDisHeaSet.x1); connect(conHal.y, conTDisHeaSet.x2); connect(TSupSet, conTDisHeaSet.f1); connect(addPar.y, conTDisHeaSet.f2); connect(uHea, conTDisHeaSet.u); connect(conTDisHeaSet.y, swi3.u1); connect(swi3.y, conVal.u_s); connect(TDis, conVal.u_m); connect(or2.y, conVal.trigger); connect(or2.y, swi4.u2); connect(conVal.y, swi4.u1); connect(conZer2.y, swi4.u3); connect(conZer2.y, watValPosUno.u1); connect(swi4.y, watValPosUno.u3); connect(uOpeMod, isOcc.u2); connect(occMod.y, isOcc.u1); connect(lowMin.y, and1.u1); connect(isOcc.y, and1.u2); connect(and1.y, or2.u1); connect(swi3.y, TDisSet); connect(unOcc.y, isUno.u1); connect(uOpeMod, isUno.u2); connect(conZer2.y, damPosUno.u1); connect(isUno.y, damPosUno.u2); connect(isUno.y, watValPosUno.u2); connect(TSupSet, max1.u1); connect(lowDisAirTem.y, max1.u2); 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(zerFlo.y,add1. u1); connect(forZerFlo.y,or3. u1); connect(forCooMax.y,or3. u2); connect(forMinFlo.y,or3. u3); connect(add1.y, swi6.u1); connect(oveFloSet,forMinFlo1. u1); connect(conInt5.y,forMinFlo1. u2); connect(forMinFlo1.y,heaMax. u); connect(minFlo.y,add4. u1); connect(heaMax.y,add4. u2); connect(or3.y,or1. u1); connect(forMinFlo1.y,or1. u2); connect(or1.y, swi6.u2); connect(add2.y, add1.u2); connect(add4.y, add2.u2); connect(cooMax.y, add2.u1); connect(swi.y, swi6.u3); connect(swi6.y, VDisSet_flowNor.u1); connect(swi6.y, VSet_flow); connect(cooMax1.y, max2.u1); connect(heaMax1.y, max2.u2); connect(max2.y, VDisSet_flowNor.u2); connect(max2.y, VDis_flowNor.u2); connect(greThr2.y, truFalHol.u); connect(greThr1.y, truFalHol1.u); connect(truFalHol1.y, not1.u); connect(truFalHol1.y, and4.u1); connect(truFalHol1.y, swi.u2); connect(truFalHol.y, not2.u); connect(truFalHol.y, or2.u2); connect(truFalHol.y, swi3.u2); connect(u1Fan, conDam.trigger); connect(max1.y, swi3.u3); end DamperValves;

Buildings.Controls.OBC.ASHRAE.G36.TerminalUnits.Reheat.Subsequences.Overrides Buildings.Controls.OBC.ASHRAE.G36.TerminalUnits.Reheat.Subsequences.Overrides

Software switches to override setpoints

Buildings.Controls.OBC.ASHRAE.G36.TerminalUnits.Reheat.Subsequences.Overrides

Information

This block considers the overrides to the setpoints for terminal unit with reheat. The implementation is according to the Section 5.6.7 of ASHRAE Guideline 36, May 2020.

Provide software switches that interlock to a system-level point to:

  1. when oveDamPos equals to 1, force the damper to full closed by setting yDam to 0,
  2. when oveDamPos equals to 2, force the damper to full open by setting yDam to 1.
  3. when uHeaOff equals to true, force the heating valve to full closed by setting yVal to 0.

Connectors

TypeNameDescription
input IntegerInputoveDamPosIndex of overriding damper position, 1: set to close; 2: set to open
input RealInputuDamDamper commanded position [1]
input BooleanInputuHeaOffOverride heating valve position, true: close heating valve
input RealInputuValHeating valve commanded position [1]
output RealOutputyDamDamper commanded position, after considering override [1]
output RealOutputyValHeating valve commanded position, after considering override [1]

Modelica definition

block Overrides "Software switches to override setpoints" Buildings.Controls.OBC.CDL.Interfaces.IntegerInput oveDamPos "Index of overriding damper position, 1: set to close; 2: set to open"; Buildings.Controls.OBC.CDL.Interfaces.RealInput uDam( final min=0, final unit="1") "Damper commanded position"; Buildings.Controls.OBC.CDL.Interfaces.BooleanInput uHeaOff "Override heating valve position, true: close heating valve"; Buildings.Controls.OBC.CDL.Interfaces.RealInput uVal( final min=0, final unit="1") "Heating valve commanded position"; Buildings.Controls.OBC.CDL.Interfaces.RealOutput yDam( final min=0, final unit="1") "Damper commanded position, after considering override"; Buildings.Controls.OBC.CDL.Interfaces.RealOutput yVal( final min=0, final unit="1") "Heating valve commanded position, after considering override"; 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.Reals.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.Reals.Switch swi1 "Damper setpoint position after considering override"; Buildings.Controls.OBC.CDL.Reals.Multiply pro "Valve position setpoint after considering override"; Buildings.Controls.OBC.CDL.Conversions.BooleanToReal booToRea( final realTrue=0, final realFalse=1) "Convert boolean true to real 0"; equation connect(conInt3.y, intEqu3.u2); connect(conInt4.y,intEqu4. u2); connect(oveDamPos, intEqu3.u1); connect(oveDamPos, 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(uDam, swi1.u3); connect(swi1.y, yDam); connect(uHeaOff, booToRea.u); connect(booToRea.y, pro.u1); connect(uVal, pro.u2); connect(pro.y,yVal); end Overrides;

Buildings.Controls.OBC.ASHRAE.G36.TerminalUnits.Reheat.Subsequences.SystemRequests Buildings.Controls.OBC.ASHRAE.G36.TerminalUnits.Reheat.Subsequences.SystemRequests

Output system requests for VAV terminal unit with reheat

Buildings.Controls.OBC.ASHRAE.G36.TerminalUnits.Reheat.Subsequences.SystemRequests

Information

This sequence outputs the system reset requests for terminal unit with reheat. The implementation is according to the Section 5.6.8 of ASHRAE Guideline 36, May 2020.

Cooling SAT reset requests yZonTemResReq

  1. If the zone temperature TZon exceeds the zone cooling setpoint TCooSet by 3 °C (5 °F)) for 2 minutes and after suppression period (uAftSup=true) due to setpoint change per G36 Part 5.1.20, send 3 requests (yZonTemResReq=3).
  2. Else if the zone temperature TZon exceeds the zone cooling setpoint TCooSet by 2 °C (3 °F) for 2 minutes and after suppression period (uAftSup=true) due to setpoint change per G36 Part 5.1.20, send 2 requests (yZonTemResReq=2).
  3. Else if the cooling loop uCoo is greater than 95%, send 1 request (yZonTemResReq=1) until uCoo is less than 85%.
  4. Else if uCoo is less than 95%, send 0 request (yZonTemResReq=0).

Static pressure reset requests yZonPreResReq

  1. If the measured airflow VDis_flow is less than 50% of setpoint VSet_flow while the setpoint is greater than zero and the damper position uDam is greater than 95% for 1 minute, send 3 requests (yZonPreResReq=3).
  2. Else if the measured airflow VDis_flow is less than 70% of setpoint VSet_flow while the setpoint is greater than zero and the damper position uDam is greater than 95% for 1 minute, send 2 requests (yZonPreResReq=2).
  3. Else if the damper position uDam is greater than 95%, send 1 request (yZonPreResReq=1) until uDam is less than 85%.
  4. Else if the damper position uDam is less than 95%, send 0 request (yZonPreResReq=0).

If there is a hot-water coil (have_hotWatCoi=true), hot-water reset requests yHeaValResReq

  1. If the discharging air temperature TDis is 17 °C (30 °F) thrTDis_1 less than the setpoint TDisSet for 5 minutes, send 3 requests.
  2. Else ff the discharging air temperature TDis is 8 °C (15 °F) thrTDis_1 less than the setpoint TDisSet for 5 minutes, send 2 requests.
  3. Else if the hot water valve position uVal is greater than 95%, send 1 request until the hot water valve position is less than 85%.
  4. Else if the hot water valve position uVal is less than 95%, send 0 request.

If there is a hot-water coil and heating hot-water plant, heating hot-water plant reqeusts. Send the heating hot-water plant that serves the zone a heating hot-water plant request as follows:

  1. If the hot water valve position uVal is greater than 95%, send 1 request until the hot water valve position is less than 10%.
  2. If the hot water valve position uVal is less than 95%, send 0 requests.

Parameters

TypeNameDefaultDescription
Booleanhave_hotWatCoi True: the system has hot water coil
RealthrTemDif3Threshold difference between zone temperature and cooling setpoint for generating 3 cooling SAT reset requests [K]
RealtwoTemDif2Threshold difference between zone temperature and cooling setpoint for generating 2 cooling SAT reset requests [K]
RealthrTDis_117Threshold difference between discharge air temperature and its setpoint for generating 3 hot water reset requests [K]
RealthrTDis_28Threshold difference between discharge air temperature and its setpoint for generating 2 hot water reset requests [K]
Duration times
RealdurTimTem120Duration time of zone temperature exceeds setpoint [s]
RealdurTimFlo60Duration time of airflow rate less than setpoint [s]
RealdurTimDisAir300Duration time of discharge air temperature less than setpoint [s]
Advanced
RealdTHys0.25Near zero temperature difference, below which the difference will be seen as zero [K]
RealfloHys Near zero flow rate, below which the flow rate or difference will be seen as zero [m3/s]
ReallooHys Loop output hysteresis below which the output will be seen as zero [1]
RealdamPosHys Near zero damper position, below which the damper will be seen as closed [1]
RealvalPosHys Near zero valve position, below which the valve will be seen as closed [1]
RealsamplePeriod120Sample period of component, set to the same value as the trim and respond that process yPreSetReq [s]

Connectors

TypeNameDescription
input BooleanInputuAftSupAfter suppression period due to the setpoint change
input RealInputTCooSetZone cooling setpoint temperature [K]
input RealInputTZonZone temperature [K]
input RealInputuCooCooling loop signal [1]
input RealInputVSet_flowDischarge airflow rate setpoint [m3/s]
input RealInputVDis_flowMeasured discharge airflow rate [m3/s]
input RealInputuDamDamper position setpoint [1]
input RealInputTDisSetDischarge airflow setpoint temperature for heating [K]
input RealInputTDisMeasured discharge airflow temperature [K]
input RealInputuValHot water valve position setpoint [1]
output IntegerOutputyZonTemResReqZone cooling supply air temperature reset request
output IntegerOutputyZonPreResReqZone static pressure reset requests
output IntegerOutputyHeaValResReqHot water reset requests
output IntegerOutputyHotWatPlaReqRequest to heating hot-water plant

Modelica definition

block SystemRequests "Output system requests for VAV terminal unit with reheat" parameter Boolean have_hotWatCoi "True: the system has hot water coil"; 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 thrTDis_1( final unit="K", final quantity="TemperatureDifference")=17 "Threshold difference between discharge air temperature and its setpoint for generating 3 hot water reset requests"; parameter Real thrTDis_2( final unit="K", final quantity="TemperatureDifference")=8 "Threshold difference between discharge air temperature and its setpoint for generating 2 hot water 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 durTimDisAir( final unit="s", final quantity="Time")=300 "Duration time of discharge air temperature 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"; parameter Real valPosHys( final unit="1") "Near zero valve position, below which the valve will be seen as closed"; parameter Real samplePeriod( final unit="s", final quantity="Time")=120 "Sample period of component, set to the same value as the trim and respond that process yPreSetReq"; Buildings.Controls.OBC.CDL.Interfaces.BooleanInput uAftSup "After suppression period due to the 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.RealInput VSet_flow( 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 uDam( final min=0, final max=1, final unit="1") "Damper position setpoint"; Buildings.Controls.OBC.CDL.Interfaces.RealInput TDisSet( final unit="K", final displayUnit="degC", final quantity="ThermodynamicTemperature") if have_hotWatCoi "Discharge airflow setpoint temperature for heating"; Buildings.Controls.OBC.CDL.Interfaces.RealInput TDis( final unit="K", final displayUnit="degC", final quantity="ThermodynamicTemperature") if have_hotWatCoi "Measured discharge airflow temperature"; Buildings.Controls.OBC.CDL.Interfaces.RealInput uVal( final min=0, final max=1, final unit="1") if have_hotWatCoi "Hot water valve position setpoint"; Buildings.Controls.OBC.CDL.Interfaces.IntegerOutput yZonTemResReq "Zone cooling supply air temperature reset request"; Buildings.Controls.OBC.CDL.Interfaces.IntegerOutput yZonPreResReq "Zone static pressure reset requests"; Buildings.Controls.OBC.CDL.Interfaces.IntegerOutput yHeaValResReq if have_hotWatCoi "Hot water reset requests"; Buildings.Controls.OBC.CDL.Interfaces.IntegerOutput yHotWatPlaReq if have_hotWatCoi "Request to heating hot-water plant"; protected Buildings.Controls.OBC.CDL.Reals.Less les( final h=dTHys) if have_hotWatCoi "Check if discharge temperature is less than setpoint by a threshold"; Buildings.Controls.OBC.CDL.Reals.Less les1( final h=dTHys) if have_hotWatCoi "Check if discharge temperature is less than setpoint by a threshold"; Buildings.Controls.OBC.CDL.Reals.GreaterThreshold greThr1( final t=thrTemDif, final h=dTHys) "Check if zone temperature is greater than cooling setpoint by threshold"; Buildings.Controls.OBC.CDL.Reals.GreaterThreshold greThr2( final t=twoTemDif, final h=dTHys) "Check if zone temperature is greater than cooling setpoint by threshold"; Buildings.Controls.OBC.CDL.Reals.GreaterThreshold greThr3( final t=0.95, final h=damPosHys) "Check if damper position is greater than 0.95"; Buildings.Controls.OBC.CDL.Reals.GreaterThreshold greThr( final t=0.95, final h=looHys) "Check if cooling loop signal is greater than 0.95"; Buildings.Controls.OBC.CDL.Reals.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.Reals.MultiplyByParameter gai1( final k=0.5) "50% of setpoint"; Buildings.Controls.OBC.CDL.Reals.MultiplyByParameter gai2( final k=0.7) "70% of setpoint"; Buildings.Controls.OBC.CDL.Reals.Subtract sub2 "Calculate difference between zone temperature and cooling setpoint"; Buildings.Controls.OBC.CDL.Reals.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.Reals.Greater greEqu( final h=floHys) "Check if discharge airflow is less than 50% of setpoint"; Buildings.Controls.OBC.CDL.Reals.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.Reals.AddParameter addPar( final p=thrTDis_1) if have_hotWatCoi "Discharge temperature plus threshold"; Buildings.Controls.OBC.CDL.Reals.AddParameter addPar1( final p=thrTDis_2) if have_hotWatCoi "Discharge temperature plus threshold"; Buildings.Controls.OBC.CDL.Integers.Sources.Constant thrHeaResReq( final k=3) if have_hotWatCoi "Constant 3"; Buildings.Controls.OBC.CDL.Integers.Sources.Constant twoHeaResReq( final k=2) if have_hotWatCoi "Constant 2"; Buildings.Controls.OBC.CDL.Integers.Switch intSwi2 if have_hotWatCoi "Output 3 or other request "; Buildings.Controls.OBC.CDL.Integers.Switch intSwi3 if have_hotWatCoi "Output 2 or other request "; Buildings.Controls.OBC.CDL.Logical.TrueDelay tim4( final delayTime=durTimDisAir) if have_hotWatCoi "Check if it is more than threshold time"; Buildings.Controls.OBC.CDL.Logical.TrueDelay tim5( final delayTime=durTimDisAir) if have_hotWatCoi "Check if it is more than threshold time"; Buildings.Controls.OBC.CDL.Reals.GreaterThreshold greThr5( final t=0.95, final h=valPosHys) if have_hotWatCoi "Check if valve position is greater than 0.95"; Buildings.Controls.OBC.CDL.Conversions.BooleanToInteger booToInt2 if have_hotWatCoi "Convert boolean to integer"; Buildings.Controls.OBC.CDL.Reals.GreaterThreshold greThr6( final t=0.95, final h=0.85) if have_hotWatCoi "Check if valve position is greater than 0.95"; Buildings.Controls.OBC.CDL.Conversions.BooleanToInteger booToInt3 if have_hotWatCoi "Convert boolean to integer"; Buildings.Controls.OBC.CDL.Discrete.Sampler sampler( final samplePeriod=samplePeriod) "Sample input signal, as the output signal will go to the trim and respond which also samples at samplePeriod"; Buildings.Controls.OBC.CDL.Discrete.Sampler sampler1( final samplePeriod=samplePeriod) "Sample input signal, as the output signal will go to the trim and respond which also samples at samplePeriod"; Buildings.Controls.OBC.CDL.Discrete.Sampler sampler2( final samplePeriod=samplePeriod) "Sample input signal, as the output signal will go to the trim and respond which also samples at samplePeriod"; Buildings.Controls.OBC.CDL.Discrete.Sampler sampler3( final samplePeriod=samplePeriod) "Sample input signal, as the output signal will go to the trim and respond which also samples at samplePeriod"; 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(greEqu.u1, gai1.y); connect(greEqu.y, and3.u2); connect(gai2.y, greEqu1.u1); connect(greEqu1.y, and4.u2); connect(uAftSup, and2.u1); connect(uAftSup, and1.u1); connect(thrCooResReq.y, intSwi.u1); connect(twoCooResReq.y, intSwi1.u1); connect(intSwi1.y, intSwi.u3); connect(intSwi.y, yZonTemResReq); connect(greThr.y, booToInt.u); connect(booToInt.y, intSwi1.u3); 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(swi4.y, yZonPreResReq); connect(TDis,addPar. u); connect(TDis,addPar1. u); connect(tim5.y, intSwi3.u2); connect(tim4.y, intSwi2.u2); connect(addPar.y, les.u1); connect(TDisSet, les.u2); connect(les.y, tim4.u); connect(TDisSet, les1.u2); connect(addPar1.y, les1.u1); connect(les1.y, tim5.u); connect(yHeaValResReq, intSwi2.y); connect(thrHeaResReq.y, intSwi2.u1); connect(twoHeaResReq.y, intSwi3.u1); connect(intSwi3.y, intSwi2.u3); connect(uVal, greThr5.u); connect(greThr5.y, booToInt2.u); connect(booToInt2.y, intSwi3.u3); connect(uVal, greThr6.u); connect(greThr6.y, booToInt3.u); connect(booToInt3.y, yHotWatPlaReq); connect(TCooSet, sub2.u2); connect(TCooSet, sub3.u2); connect(TZon, sub2.u1); connect(TZon, sub3.u1); connect(uCoo, sampler.u); connect(sampler.y, greThr.u); connect(uDam, sampler1.u); connect(sampler1.y, greThr3.u); connect(VDis_flow, sampler2.u); connect(sampler2.y, greEqu.u2); connect(sampler2.y, greEqu1.u2); connect(VSet_flow, sampler3.u); connect(sampler3.y, greThr4.u); connect(sampler3.y, gai1.u); connect(sampler3.y, gai2.u); end SystemRequests;