Buildings.Templates.AirHandlersFans
Air handlers and fans
Information
This package contains templates for air handlers and fans.
Extends from Modelica.Icons.Package (Icon for standard packages).
Package Content
| Name | Description |
|---|---|
 VAVMultiZone
|
Multiple-zone VAV |
 Components
|
Package with component models |
 Data
|
Records for design and operating parameters |
 Types
|
Package with type definitions |
 Validation
|
Package with validation models |
 Interfaces
|
Interface classes |
Buildings.Templates.AirHandlersFans.VAVMultiZone
Multiple-zone VAV
Information
Description
This template represents a multiple-zone VAV air handler for a single duct system serving at least two terminal units.
The possible configuration options are enumerated in the table below.
The user may refer to ASHRAE (2021) for further details.
The first option displayed in bold characters corresponds to the default configuration.
| Configuration parameter | Options | Notes |
|---|---|---|
| Outdoor air section |
Single damper for ventilation and economizer, with airflow measurement station Separate dampers for ventilation and economizer, with airflow measurement station Separate dampers for ventilation and economizer, with differential pressure sensor |
|
| Relief/return air section |
Return fan with modulating relief damper Modulating relief damper without fan Relief fan with two-position relief damper |
Nonactuated barometric relief is currently not supported. |
| Supply fan - Blow-through position |
No fan Single fan - Variable speed Fan array - Variable speed |
At least one supply fan must be specified, either in blow-through
or draw-through position. Those two configurations are exclusive from
one another. ASHRAE Guideline 36 does not have any particular logic yet for handling fan arrays. If a fan array is selected, all of the fans are currently controlled together at the same speed, regardless of the number of VFDs. |
| Heating coil - Preheat position |
Hot water coil with two-way valve Modulating electric heating coil No coil |
|
| Cooling coil |
Chilled water coil with two-way valve No coil |
|
| Heating coil - Reheat position | No coil | ASHRAE Guideline 36 does not support heating coils in reheat position yet. |
| Supply fan - Draw-through position |
Single fan - Variable speed Fan array - Variable speed No fan |
At least one supply fan must be specified, either in blow-through
or draw-through position. Those two configurations are exclusive from
one another. ASHRAE Guideline 36 does not have any particular logic yet for handling fan arrays. If a fan array is selected, all of the fans are currently controlled together at the same speed, regardless of the number of VFDs. |
| Return fan |
Single fan - Variable speed Fan array - Variable speed No fan |
The relief fan and the return fan are both optional and they are exclusive from one another. |
| Relief fan |
No fan Single fan - Variable speed Fan array - Variable speed |
The relief fan and the return fan are both optional and they are exclusive from one another. |
| Controller | ASHRAE Guideline 36 controller | An open loop controller is also available for validation purposes only. |
| Exhaust fan | Not available: see note | All exhaust fans that normally operate with the air handler must be configured separately, by means of a dedicated template. |
| Heat recovery | Not available: see note | Currently no heat recovery equipment is supported. |
Simulation model assumptions and requirements
Pressure reference
The duct static pressure sensors use the outdoor absolute pressure as an approximation of the reference pressure in the mechanical room where the air handler is located.
When a building static pressure measurement is required by the control
sequence
(ctl.typCtlFanRet=AirHandlersFans.Types.ControlFanReturn.BuildingPressure),
the corresponding sensor pBui_rel is instantiated
within the current class.
In this case, an additional variable pBui needs to be
connected to the control bus to pass in the value of the absolute pressure
in a representative space of the building.
This is a modeling requirement, the actual control point remains the
relative building static pressure.
References
- ASHRAE, 2021. Guideline 36-2021, High-Performance Sequences of Operation for HVAC Systems. Atlanta, GA.
Extends from Buildings.Templates.AirHandlersFans.Interfaces.PartialAirHandler (Interface class for air handler).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| replaceable package MediumAir | Air | Air medium | |
| replaceable package MediumChiWat | Water | CHW medium | |
| replaceable package MediumHeaWat | Water | HHW medium | |
| Configuration | |||
| Configuration | typ | Buildings.Templates.AirHandl... | Type of system |
| Boolean | have_porRel | secOutRel.typ <> Types.Outdo... | Set to true for relief (exhaust) fluid port |
| Boolean | have_souChiWat | coiCoo.have_sou | Set to true if system uses CHW |
| Boolean | have_souHeaWat | coiHeaPre.have_sou or coiHea... | Set to true if system uses HHW |
| Fan | typFanSup | if fanSupDra.typ <> Building... | Type of supply fan |
| Fan | typFanRet | secOutRel.typFanRet | Type of return fan |
| Fan | typFanRel | secOutRel.typFanRel | Type of relief fan |
| MixedAirWithDamper | secOutRel | secOutRel(redeclare final pa... | Outdoor/relief/return air section |
| None | fanSupBlo | redeclare inner Buildings.Te... | Supply fan - Blow through |
| SingleVariable | fanSupDra | redeclare inner Buildings.Te... | Supply fan - Draw through |
| WaterBasedHeating | coiHeaPre | coiHeaPre(redeclare final pa... | Heating coil in preheat position |
| WaterBasedCooling | coiCoo | coiCoo(redeclare final packa... | Cooling coil |
| None | coiHeaReh | redeclare inner Buildings.Te... | Heating coil in reheat position |
| Nominal condition | |||
| MassFlowRate | mChiWat_flow_nominal | if coiCoo.have_sou then dat.... | Total CHW mass flow rate [kg/s] |
| MassFlowRate | mHeaWat_flow_nominal | (if coiHeaPre.have_sou then ... | Total HHW mass flow rate [kg/s] |
| HeatFlowRate | QChiWat_flow_nominal | if coiCoo.have_sou then dat.... | Total CHW heat flow rate [W] |
| HeatFlowRate | QHeaWat_flow_nominal | (if coiHeaPre.have_sou then ... | Total HHW heat flow rate [W] |
| Controls | |||
| G36VAVMultiZone | ctl | redeclare inner Buildings.Te... | Control selections |
| Dynamics | |||
| Conservation equations | |||
| Dynamics | energyDynamics | Modelica.Fluid.Types.Dynamic... | Type of energy balance: dynamic (3 initialization options) or steady state |
| Assumptions | |||
| Boolean | allowFlowReversalLiq | true | = true to allow flow reversal, false restricts to design direction - CHW and HW side |
| Advanced | |||
| Diagnostics | |||
| Boolean | show_T | false | = true, if actual temperature at ports of subcomponents is computed |
Connectors
| Type | Name | Description |
|---|---|---|
| FluidPort_a | port_Out | Outdoor air intake |
| FluidPort_b | port_Sup | Supply air |
| FluidPort_b | port_SupCol | Dual duct cold deck air supply |
| FluidPort_b | port_SupHot | Dual duct hot deck air supply |
| FluidPort_a | port_Ret | Return air |
| FluidPort_b | port_Rel | Relief (exhaust) air |
| FluidPort_b | port_bChiWat | CHW return port |
| FluidPort_a | port_aChiWat | CHW supply port |
| FluidPort_b | port_bHeaWat | HHW return port |
| FluidPort_a | port_aHeaWat | HHW supply port |
| Bus | bus | AHU control bus |
| Bus | busWea | Weather bus |
| Bus | busTer[nZon] | Terminal unit control bus |
Modelica definition
model VAVMultiZone "Multiple-zone VAV"
/*
HACK: In Dymola only (ticket SR00860858-01), bindings for the parameter record
cannot be made final if propagation from a top-level record (whole building)
is needed.
Instead those parameter declarations are annoted with enable=false
in the record class.
*/
extends Buildings.Templates.AirHandlersFans.Interfaces.PartialAirHandler(
nZon(final min=2),
redeclare Buildings.Templates.AirHandlersFans.Data.VAVMultiZone dat(
typCoiHeaPre=coiHeaPre.typ,
typCoiCoo=coiCoo.typ,
typCoiHeaReh=coiHeaReh.typ,
typValCoiHeaPre=coiHeaPre.typVal,
typValCoiCoo=coiCoo.typVal,
typValCoiHeaReh=coiHeaReh.typVal,
typDamOut=secOutRel.typDamOut,
typDamOutMin=secOutRel.typDamOutMin,
typDamRet=secOutRel.typDamRet,
typDamRel=secOutRel.typDamRel,
typSecOut=secOutRel.typSecOut,
typCtl=ctl.typ,
buiPreCon=ctl.buiPreCon,
stdVen=ctl.stdVen),
final typ=Buildings.Templates.AirHandlersFans.Types.Configuration.SingleDuct,
final have_porRel=secOutRel.typ <> Types.OutdoorReliefReturnSection.MixedAirNoRelief,
final have_souChiWat=coiCoo.have_sou,
final have_souHeaWat=coiHeaPre.have_sou or coiHeaReh.have_sou,
final typFanSup=if
fanSupDra.typ <> Buildings.Templates.Components.Types.Fan.None then
fanSupDra.typ elseif fanSupBlo.typ <> Buildings.Templates.Components.Types.Fan.None
then fanSupBlo.typ else Buildings.Templates.Components.Types.Fan.None,
final typFanRel=secOutRel.typFanRel,
final typFanRet=secOutRel.typFanRet,
final mChiWat_flow_nominal=if coiCoo.have_sou then dat.coiCoo.mWat_flow_nominal else 0,
final mHeaWat_flow_nominal=(if coiHeaPre.have_sou then dat.coiHeaPre.mWat_flow_nominal else 0) +
(if coiHeaReh.have_sou then dat.coiHeaReh.mWat_flow_nominal else 0),
final QChiWat_flow_nominal=if coiCoo.have_sou then dat.coiCoo.Q_flow_nominal else 0,
final QHeaWat_flow_nominal=(if coiHeaPre.have_sou then dat.coiHeaPre.Q_flow_nominal else 0) +
(if coiHeaReh.have_sou then dat.coiHeaReh.Q_flow_nominal else 0));
final parameter Boolean have_senPreBui=
secOutRel.typSecRel==Buildings.Templates.AirHandlersFans.Types.ReliefReturnSection.ReliefDamper or
secOutRel.typSecRel==Buildings.Templates.AirHandlersFans.Types.ReliefReturnSection.ReliefFan or
secOutRel.typSecRel==Buildings.Templates.AirHandlersFans.Types.ReliefReturnSection.ReturnFan and
secOutRel.typCtlFanRet==Buildings.Templates.AirHandlersFans.Types.ControlFanReturn.BuildingPressure
"Set to true if building static pressure sensor is used";
/*
RFE: Currently only the configuration with economizer is supported.
Hence, no choices annotation, but still replaceable to access parameter
dialog box of the component.
*/
inner Buildings.Templates.AirHandlersFans.Components.OutdoorReliefReturnSection.MixedAirWithDamper
secOutRel(
redeclare final package MediumAir = MediumAir,
final typCtlFanRet=ctl.typCtlFanRet,
final typCtlEco=ctl.typCtlEco,
final energyDynamics=energyDynamics,
final allowFlowReversal=allowFlowReversalAir,
dat(
final mOutMin_flow_nominal=dat.mOutMin_flow_nominal,
final damOut=dat.damOut,
final damOutMin=dat.damOutMin,
final damRel=dat.damRel,
final damRet=dat.damRet,
final fanRel=dat.fanRel,
final fanRet=dat.fanRet))
"Outdoor/relief/return air section";
Buildings.Templates.Components.Sensors.Temperature TAirMix(
redeclare final package Medium = MediumAir,
final have_sen=ctl.use_TMix,
final typ=Buildings.Templates.Components.Types.SensorTemperature.Averaging,
final m_flow_nominal=mAirSup_flow_nominal,
final allowFlowReversal=allowFlowReversalAir)
"Mixed air temperature sensor";
inner replaceable Buildings.Templates.Components.Fans.None fanSupBlo
constrainedby Buildings.Templates.Components.Interfaces.PartialFan(
redeclare final package Medium = MediumAir,
final energyDynamics=energyDynamics,
final allowFlowReversal=allowFlowReversalAir,
final dat=dat.fanSup,
final have_senFlo=ctl.typCtlFanRet==
Buildings.Templates.AirHandlersFans.Types.ControlFanReturn.AirflowMeasured)
"Supply fan - Blow through";
Buildings.Templates.Components.Sensors.Temperature TAirCoiHeaLvg(
redeclare final package Medium = MediumAir,
final have_sen=coiHeaPre.typ <> Buildings.Templates.Components.Types.Coil.None
and coiCoo.typ <> Buildings.Templates.Components.Types.Coil.None,
final typ=Buildings.Templates.Components.Types.SensorTemperature.Averaging,
final m_flow_nominal=mAirSup_flow_nominal,
final allowFlowReversal=allowFlowReversalAir)
"Heating coil leaving air temperature sensor";
Buildings.Templates.Components.Sensors.Temperature TAirCoiCooLvg(
redeclare final package Medium = MediumAir,
final have_sen=coiCoo.typ <> Buildings.Templates.Components.Types.Coil.None
and coiHeaReh.typ <> Buildings.Templates.Components.Types.Coil.None,
final typ=Buildings.Templates.Components.Types.SensorTemperature.Averaging,
final m_flow_nominal=mAirSup_flow_nominal,
final allowFlowReversal=allowFlowReversalAir)
"Cooling coil leaving air temperature sensor";
inner replaceable Buildings.Templates.Components.Fans.SingleVariable fanSupDra
constrainedby Buildings.Templates.Components.Interfaces.PartialFan(
redeclare final package Medium = MediumAir,
final energyDynamics=energyDynamics,
final allowFlowReversal=allowFlowReversalAir,
final dat=dat.fanSup,
final have_senFlo=ctl.typCtlFanRet==
Buildings.Templates.AirHandlersFans.Types.ControlFanReturn.AirflowMeasured)
"Supply fan - Draw through";
Buildings.Templates.Components.Sensors.Temperature TAirSup(
redeclare final package Medium = MediumAir,
final have_sen=true,
final typ=Buildings.Templates.Components.Types.SensorTemperature.Standard,
final m_flow_nominal=mAirSup_flow_nominal,
final allowFlowReversal=allowFlowReversalAir)
"Supply air temperature sensor";
Buildings.Templates.Components.Sensors.DifferentialPressure pBui_rel(
redeclare final package Medium = MediumAir,
final have_sen=have_senPreBui,
final text_flip=true)
"Building static pressure";
Buildings.Fluid.Sources.Outside out(
redeclare final package Medium=MediumAir,
final nPorts=3)
"Outdoor conditions";
Buildings.Fluid.Sources.Boundary_pT bui(
redeclare final package Medium = MediumAir,
final use_p_in=have_senPreBui,
final nPorts=1)
"Building absolute pressure in representative space";
Buildings.Templates.Components.Sensors.Temperature TAirRet(
redeclare final package Medium = MediumAir,
final allowFlowReversal=allowFlowReversalAir,
final have_sen=
secOutRel.have_eco and
(ctl.typCtlEco==Buildings.Controls.OBC.ASHRAE.G36.Types.ControlEconomizer.DifferentialDryBulb or
ctl.typCtlEco==Buildings.Controls.OBC.ASHRAE.G36.Types.ControlEconomizer.FixedDryBulbWithDifferentialDryBulb),
final typ=Buildings.Templates.Components.Types.SensorTemperature.Standard,
final m_flow_nominal=mAirRet_flow_nominal)
"Return air temperature sensor";
Buildings.Templates.Components.Sensors.SpecificEnthalpy hAirRet(
redeclare final package Medium = MediumAir,
final allowFlowReversal=allowFlowReversalAir,
final have_sen=
secOutRel.have_eco and
ctl.typCtlEco==Buildings.Controls.OBC.ASHRAE.G36.Types.ControlEconomizer.DifferentialEnthalpyWithFixedDryBulb,
final m_flow_nominal=mAirRet_flow_nominal)
"Return air enthalpy sensor";
Buildings.Templates.Components.Sensors.DifferentialPressure pAirSup_rel(
redeclare final package Medium = MediumAir,
final have_sen=true)
"Duct static pressure sensor";
inner replaceable Buildings.Templates.Components.Coils.WaterBasedHeating coiHeaPre(
redeclare final package MediumHeaWat=MediumHeaWat,
redeclare final Buildings.Templates.Components.Valves.TwoWayModulating val)
constrainedby Buildings.Templates.Components.Interfaces.PartialCoil(
final dat=dat.coiHeaPre,
redeclare final package MediumAir=MediumAir,
final energyDynamics=energyDynamics,
final allowFlowReversalAir=allowFlowReversalAir,
final allowFlowReversalLiq=allowFlowReversalLiq,
final show_T=show_T)
"Heating coil in preheat position";
inner replaceable Buildings.Templates.Components.Coils.WaterBasedCooling coiCoo(
redeclare final package MediumChiWat=MediumChiWat,
redeclare final Buildings.Templates.Components.Valves.TwoWayModulating val)
constrainedby Buildings.Templates.Components.Interfaces.PartialCoil(
final dat=dat.coiCoo,
redeclare final package MediumAir=MediumAir,
final energyDynamics=energyDynamics,
final allowFlowReversalAir=allowFlowReversalAir,
final allowFlowReversalLiq=allowFlowReversalLiq,
final show_T=show_T)
"Cooling coil";
inner replaceable Buildings.Templates.Components.Coils.None coiHeaReh
constrainedby Buildings.Templates.Components.Interfaces.PartialCoil(
final dat=dat.coiHeaReh,
redeclare final package MediumAir=MediumAir,
final energyDynamics=energyDynamics,
final allowFlowReversalAir=allowFlowReversalAir,
final allowFlowReversalLiq=allowFlowReversalLiq,
final show_T=show_T)
"Heating coil in reheat position";
Buildings.Fluid.FixedResistances.Junction junHeaWatSup(
redeclare final package Medium = MediumHeaWat,
final m_flow_nominal=mHeaWat_flow_nominal*{1,-1,-1},
energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial,
dp_nominal=fill(0, 3),
final portFlowDirection_1=if allowFlowReversalLiq then
Modelica.Fluid.Types.PortFlowDirection.Bidirectional
else Modelica.Fluid.Types.PortFlowDirection.Entering,
final portFlowDirection_2=if allowFlowReversalLiq then
Modelica.Fluid.Types.PortFlowDirection.Bidirectional
else Modelica.Fluid.Types.PortFlowDirection.Leaving,
final portFlowDirection_3=if allowFlowReversalLiq then
Modelica.Fluid.Types.PortFlowDirection.Bidirectional
else Modelica.Fluid.Types.PortFlowDirection.Leaving) if have_souHeaWat
"HHW supply junction";
Buildings.Fluid.FixedResistances.Junction junHeaWatRet(
redeclare final package Medium = MediumHeaWat,
final m_flow_nominal=mHeaWat_flow_nominal*{1,-1,1},
energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial,
dp_nominal=fill(0, 3),
final portFlowDirection_1=if allowFlowReversalLiq then
Modelica.Fluid.Types.PortFlowDirection.Bidirectional
else Modelica.Fluid.Types.PortFlowDirection.Entering,
final portFlowDirection_2=if allowFlowReversalLiq then
Modelica.Fluid.Types.PortFlowDirection.Bidirectional
else Modelica.Fluid.Types.PortFlowDirection.Entering,
final portFlowDirection_3=if allowFlowReversalLiq then
Modelica.Fluid.Types.PortFlowDirection.Bidirectional
else Modelica.Fluid.Types.PortFlowDirection.Leaving) if have_souHeaWat
"HHW return junction";
inner replaceable Buildings.Templates.AirHandlersFans.Components.Controls.G36VAVMultiZone
ctl
constrainedby Buildings.Templates.AirHandlersFans.Components.Interfaces.PartialControllerVAVMultizone
( final dat=dat.ctl,
final nZon=nZon)
"Control selections";
initial equation
assert(typFanSup<>Buildings.Templates.Components.Types.Fan.None,
"In "+ getInstanceName() + ": "+
"The template is configured with no supply fan, which is not supported.");
assert(not (fanSupBlo.typ<>Buildings.Templates.Components.Types.Fan.None and
fanSupDra.typ<>Buildings.Templates.Components.Types.Fan.None),
"In "+ getInstanceName() + ": "+
"The template is configured with both a blow-through fan and a draw-through fan, which is not supported.");
equation
/* Control point connection - start */
connect(TAirMix.y, bus.TAirMix);
connect(TAirCoiHeaLvg.y, bus.TAirCoiHeaLvg);
connect(TAirSup.y, bus.TAirSup);
connect(pAirSup_rel.y, bus.pAirSup_rel);
connect(hAirRet.y, bus.hAirRet);
connect(TAirRet.y, bus.TAirRet);
connect(fanSupDra.bus, bus.fanSup);
connect(fanSupBlo.bus, bus.fanSup);
connect(coiHeaPre.bus, bus.coiHea);
connect(coiCoo.bus, bus.coiCoo);
connect(coiHeaReh.bus, bus.coiHea);
connect(secOutRel.bus, bus);
connect(bui.p_in, bus.pBui);
connect(pBui_rel.y, bus.pBui_rel);
/* Control point connection - stop */
connect(port_aChiWat, coiCoo.port_aSou);
connect(coiCoo.port_bSou, port_bChiWat);
connect(busWea,coiCoo.busWea);
connect(TAirMix.port_b, fanSupBlo.port_a);
connect(coiHeaReh.port_b, fanSupDra.port_a);
connect(busWea, out.weaBus);
connect(pBui_rel.port_b, out.ports[1]);
connect(bui.ports[1], pBui_rel.port_a);
connect(ctl.busTer, busTer);
connect(ctl.bus, bus);
connect(port_Ret, hAirRet.port_a);
connect(hAirRet.port_b, TAirRet.port_a);
connect(coiHeaPre.port_b, TAirCoiHeaLvg.port_a);
connect(TAirCoiHeaLvg.port_b, coiCoo.port_a);
connect(coiCoo.port_b, TAirCoiCooLvg.port_a);
connect(TAirCoiCooLvg.port_b, coiHeaReh.port_a);
connect(secOutRel.port_Sup, TAirMix.port_a);
connect(secOutRel.port_bPre, out.ports[2]);
connect(port_Rel, secOutRel.port_Rel);
connect(port_Out, secOutRel.port_Out);
connect(TAirSup.port_b, port_Sup);
connect(TAirSup.port_b, pAirSup_rel.port_a);
connect(fanSupDra.port_b, TAirSup.port_a);
connect(port_aHeaWat, junHeaWatSup.port_1);
connect(port_bHeaWat, junHeaWatRet.port_2);
connect(junHeaWatSup.port_3, coiHeaReh.port_aSou);
connect(coiHeaReh.port_bSou, junHeaWatRet.port_3);
connect(coiHeaPre.port_bSou, junHeaWatRet.port_1);
connect(junHeaWatSup.port_2, coiHeaPre.port_aSou);
connect(out.ports[3], pAirSup_rel.port_b);
connect(secOutRel.port_Ret, TAirRet.port_b);
connect(fanSupBlo.port_b, coiHeaPre.port_a);
end VAVMultiZone;