Buildings.Templates.Plants.Controls.HeatRecoveryChillers
Package of sequences for heat recovery chillers
Information
This package contains control sequences for heat recovery chillers.
Package Content
| Name | Description |
|---|---|
 Controller
|
Sidestream heat recovery chiller controller |
 Enable
|
Heat recovery chiller and HRC CHW and HW pumps enable |
 ModeControl
|
Mode control and setpoint selection |
 Validation
|
Collection of validation models |
Buildings.Templates.Plants.Controls.HeatRecoveryChillers.Controller
Sidestream heat recovery chiller controller
Information
The control sequence consists of the following parts.
- Heat recovery chiller enable logic: Refer to Buildings.Templates.Plants.Controls.HeatRecoveryChillers.Enable.
- Heat recovery chiller CHW and HW pump control: The logic assumes constant speed pumps. The pumps are enabled as described in Buildings.Templates.Plants.Controls.HeatRecoveryChillers.Enable and disabled as described in Buildings.Templates.Plants.Controls.Pumps.Primary.DisableDedicated.
- Heat recovery chiller mode control and setpoint selection: Refer to Buildings.Templates.Plants.Controls.HeatRecoveryChillers.ModeControl.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Boolean | have_reqFlo | false | Set to true if HRC provides flow request point via network interface |
| Real | cp_default | Default specific heat capacity used to compute required capacity [J/(kg.K)] | |
| Real | rho_default | Default fluid density used to compute required capacity [kg/m3] | |
| Real | dtMea | 300 | Duration used to compute the moving average of required capacity [s] |
| Real | dtRun | 15*60 | Minimum runtime of enable and disable states [s] |
| Real | dtLoa | 10*60 | Runtime with sufficient load before enabling [s] |
| Real | dtTem1 | 3*60 | Runtime with first temperature threshold exceeded before disabling [s] |
| Real | dtTem2 | 1*60 | Runtime with second temperature threshold exceeded before disabling [s] |
| Information provided by designer | |||
| Real | TChiWatSup_min | Minimum allowable CHW supply temperature [K] | |
| Real | THeaWatSup_max | Maximum allowable HW supply temperature [K] | |
| Real | COPHea_nominal | Heating COP at design heating conditions [1] | |
| Real | capCoo_min | Minimum cooling capacity below which cycling occurs [W] | |
| Real | capHea_min | Minimum heating capacity below which cycling occurs [W] | |
Connectors
| Type | Name | Description |
|---|---|---|
| input RealInput | TChiWatRetUpsHrc | CHW return temperature upstream of HRC [K] |
| input RealInput | TChiWatSupSet | Active CHW supply temperature setpoint [K] |
| input RealInput | VChiWatLoa_flow | CHW volume flow rate distributed to the loads [m3/s] |
| input RealInput | THeaWatRetUpsHrc | HW return temperature upstream of HRC [K] |
| input RealInput | THeaWatSupSet | Active HW supply temperature setpoint [K] |
| input RealInput | VHeaWatLoa_flow | HW volume flow rate distributed to the loads [m3/s] |
| input RealInput | TChiWatHrcLvg | HRC leaving CHW temperature [K] |
| input RealInput | THeaWatHrcLvg | HRC leaving HW temperature [K] |
| input BooleanInput | u1Coo | Cooling plant enable |
| input BooleanInput | u1Hea | Heating plant enable |
| input BooleanInput | u1Hrc_actual | HRC status |
| input BooleanInput | u1ReqFloChiWat | CHW flow request from HRC |
| input BooleanInput | u1ReqFloConWat | CW flow request from HRC |
| output BooleanOutput | y1 | Enable command |
| output BooleanOutput | y1Coo | Mode command: true for cooling, false for heating |
| output BooleanOutput | y1PumChiWat | HRC CHW pump enable command |
| output BooleanOutput | y1PumHeaWat | HRC HW pump enable command |
| output RealOutput | TSupSet | Active supply temperature setpoint [K] |
Modelica definition
block Controller
"Sidestream heat recovery chiller controller"
parameter Boolean have_reqFlo=false
"Set to true if HRC provides flow request point via network interface";
parameter Real TChiWatSup_min(
min=273.15,
start=4 + 273.15,
unit="K",
displayUnit="degC")
"Minimum allowable CHW supply temperature";
parameter Real THeaWatSup_max(
min=273.15,
start=60 + 273.15,
unit="K",
displayUnit="degC")
"Maximum allowable HW supply temperature";
parameter Real COPHea_nominal(
min=1.1,
unit="1")
"Heating COP at design heating conditions";
parameter Real capCoo_min(
min=0,
unit="W")
"Minimum cooling capacity below which cycling occurs";
parameter Real capHea_min(
min=0,
unit="W")
"Minimum heating capacity below which cycling occurs";
parameter Real cp_default(
min=0,
unit="J/(kg.K)")
"Default specific heat capacity used to compute required capacity";
parameter Real rho_default(
min=0,
unit="kg/m3")
"Default fluid density used to compute required capacity";
parameter Real dtMea(
min=0,
unit="s")=300
"Duration used to compute the moving average of required capacity";
parameter Real dtRun(
min=0,
unit="s")=15 * 60
"Minimum runtime of enable and disable states";
parameter Real dtLoa(
min=0,
unit="s")=10 * 60
"Runtime with sufficient load before enabling";
parameter Real dtTem1(
min=0,
unit="s")=3 * 60
"Runtime with first temperature threshold exceeded before disabling";
parameter Real dtTem2(
min=0,
unit="s")=1 * 60
"Runtime with second temperature threshold exceeded before disabling";
Buildings.Controls.OBC.CDL.Interfaces.RealInput TChiWatRetUpsHrc(
final unit="K",
displayUnit="degC")
"CHW return temperature upstream of HRC";
Buildings.Controls.OBC.CDL.Interfaces.RealInput TChiWatSupSet(
final unit="K",
displayUnit="degC")
"Active CHW supply temperature setpoint";
Buildings.Controls.OBC.CDL.Interfaces.RealInput VChiWatLoa_flow(
final unit="m3/s")
"CHW volume flow rate distributed to the loads";
Buildings.Controls.OBC.CDL.Interfaces.RealInput THeaWatRetUpsHrc(
final unit="K",
displayUnit="degC")
"HW return temperature upstream of HRC";
Buildings.Controls.OBC.CDL.Interfaces.RealInput THeaWatSupSet(
final unit="K",
displayUnit="degC")
"Active HW supply temperature setpoint";
Buildings.Controls.OBC.CDL.Interfaces.RealInput VHeaWatLoa_flow(
final unit="m3/s")
"HW volume flow rate distributed to the loads";
StagingRotation.LoadAverage loaChiWat(
final typ=Buildings.Templates.Plants.Controls.Types.Application.Cooling,
final cp_default=cp_default,
final rho_default=rho_default,
final dtMea=dtMea)
"CHW load";
StagingRotation.LoadAverage loaHeaWat(
final typ=Buildings.Templates.Plants.Controls.Types.Application.Heating,
final cp_default=cp_default,
final rho_default=rho_default,
final dtMea=dtMea)
"HW load";
Buildings.Controls.OBC.CDL.Interfaces.RealInput TChiWatHrcLvg(
final unit="K",
displayUnit="degC")
"HRC leaving CHW temperature";
Buildings.Controls.OBC.CDL.Interfaces.RealInput THeaWatHrcLvg(
final unit="K",
displayUnit="degC")
"HRC leaving HW temperature";
Buildings.Controls.OBC.CDL.Interfaces.BooleanInput u1Coo
"Cooling plant enable";
Buildings.Controls.OBC.CDL.Interfaces.BooleanInput u1Hea
"Heating plant enable";
Buildings.Controls.OBC.CDL.Interfaces.BooleanInput u1Hrc_actual
"HRC status";
Buildings.Controls.OBC.CDL.Interfaces.BooleanInput u1ReqFloChiWat
if have_reqFlo
"CHW flow request from HRC";
Buildings.Controls.OBC.CDL.Interfaces.BooleanInput u1ReqFloConWat
if have_reqFlo
"CW flow request from HRC";
Buildings.Controls.OBC.CDL.Interfaces.BooleanOutput y1
"Enable command";
Buildings.Controls.OBC.CDL.Interfaces.BooleanOutput y1Coo
"Mode command: true for cooling, false for heating";
Buildings.Controls.OBC.CDL.Interfaces.BooleanOutput y1PumChiWat
"HRC CHW pump enable command";
Buildings.Controls.OBC.CDL.Interfaces.BooleanOutput y1PumHeaWat
"HRC HW pump enable command";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput TSupSet(
final unit="K",
displayUnit="degC")
"Active supply temperature setpoint";
Enable ena(
final TChiWatSup_min=TChiWatSup_min,
final THeaWatSup_max=THeaWatSup_max,
final capCoo_min=capCoo_min,
final capHea_min=capHea_min,
final dtLoa=dtLoa,
final dtRun=dtRun,
final dtTem1=dtTem1,
final dtTem2=dtTem2)
"Compute enable command";
ModeControl setMod(
final COPHea_nominal=COPHea_nominal)
"Set mode";
Pumps.Primary.DisableDedicated pumChiWat(
final have_reqFlo=have_reqFlo)
"CHW pump control";
Pumps.Primary.DisableDedicated pumHeaWat(
final have_reqFlo=have_reqFlo)
"HW pump control";
Buildings.Controls.OBC.CDL.Logical.Pre preMod
"Previous mode setting";
equation
connect(TChiWatSupSet, loaChiWat.TSupSet);
connect(TChiWatRetUpsHrc, loaChiWat.TRet);
connect(VChiWatLoa_flow, loaChiWat.V_flow);
connect(THeaWatSupSet, loaHeaWat.TSupSet);
connect(THeaWatRetUpsHrc, loaHeaWat.TRet);
connect(VHeaWatLoa_flow, loaHeaWat.V_flow);
connect(u1Coo, ena.u1Coo);
connect(u1Hea, ena.u1Hea);
connect(u1Hrc_actual, ena.u1Hrc_actual);
connect(loaChiWat.QReq_flow, ena.QChiWatReq_flow);
connect(loaHeaWat.QReq_flow, ena.QHeaWatReq_flow);
connect(TChiWatHrcLvg, ena.TChiWatHrcLvg);
connect(THeaWatHrcLvg, ena.THeaWatHrcLvg);
connect(loaChiWat.QReq_flow, setMod.QChiWatReq_flow);
connect(loaHeaWat.QReq_flow, setMod.QHeaWatReq_flow);
connect(TChiWatSupSet, setMod.TChiWatSupSet);
connect(THeaWatSupSet, setMod.THeaWatSupSet);
connect(setMod.y1Coo, y1Coo);
connect(setMod.TSupSet, TSupSet);
connect(ena.y1, y1);
connect(ena.y1SetMod, setMod.u1SetMod);
connect(ena.y1, pumChiWat.u1);
connect(ena.y1, pumChiWat.u1Equ);
connect(u1ReqFloChiWat, pumChiWat.u1ReqFlo);
connect(u1Hrc_actual, pumChiWat.u1Equ_actual);
connect(ena.y1, pumHeaWat.u1);
connect(ena.y1, pumHeaWat.u1Equ);
connect(u1ReqFloConWat, pumHeaWat.u1ReqFlo);
connect(u1Hrc_actual, pumHeaWat.u1Equ_actual);
connect(pumHeaWat.y1, y1PumHeaWat);
connect(pumChiWat.y1, y1PumChiWat);
connect(setMod.y1Coo, preMod.u);
connect(preMod.y, ena.u1CooHrc);
end Controller;
Buildings.Templates.Plants.Controls.HeatRecoveryChillers.Enable
Heat recovery chiller and HRC CHW and HW pumps enable
Information
The available CHW load QChiWatReq_flow is calculated based on secondary
CHW temperature immediately upstream of the heat recovery chiller,
active CHW supply temperature setpoint and secondary CHW loop flow.
The available HW load QHeaWatReq_flow is calculated based on secondary
HW temperature immediately upstream of the heat recovery chiller,
active HW supply temperature setpoint and secondary HW loop flow.
The available CHW and HW loads used in logic are rolling averages
over a period of dtMea
of instantaneous values sampled at minimum once every 30 s.
The heat recovery chiller is enabled when all of the following are true:
- CHW plant has been enabled for
dtRun. QChiWatReq_flow > capCooHrc_minfordtLoa.- HW plant has been enabled for
dtRun. QHeaWatReq_flow > capHeaHrc_minfordtLoa.- HRC has been disabled for at least
dtRun.
The heat recovery chiller is disabled when any of the following are true:
- CHW plant is disabled.
- HW plant is disabled.
-
The heat recovery chiller cycles off (chiller is enabled but status changes from Run to Off)
under low load conditions and either
QChiWatReq_flow < capCooHrc_minorQHeaWatReq_flow < capHeaHrc_min. -
If the HRC is in heating mode and CHW supply temperature leaving the
heat recovery chiller as measured either through the chiller’s network interface
or immediately downstream of the chiller is
< TChiWatSupSet_min + 1fordtTem1or< TChiWatSupSet_minfordtTem2. -
If the HRC is in cooling mode and HW supply temperature leaving the
heat recovery chiller as measured either through the chiller’s network interface
or immediately downstream of the chiller is
> THeaWatSupSet_max - 1.5fordtTem1or> THeaWatSupSet_maxfordtTem2.
Pump control
Sidestream HRC HW and CHW pumps are enabled when the heat recovery chiller is enabled.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Real | dtRun | 15*60 | Minimum runtime of enable and disable states [s] |
| Real | dtLoa | 10*60 | Runtime with sufficient load before enabling [s] |
| Real | dtTem1 | 3*60 | Runtime with first temperature threshold exceeded before disabling [s] |
| Real | dtTem2 | 1*60 | Runtime with second temperature threshold exceeded before disabling [s] |
| Information provided by designer | |||
| Real | TChiWatSup_min | Minimum allowable CHW supply temperature [K] | |
| Real | THeaWatSup_max | Maximum allowable HW supply temperature [K] | |
| Real | capCoo_min | Minimum cooling capacity below which cycling occurs [W] | |
| Real | capHea_min | Minimum heating capacity below which cycling occurs [W] | |
Connectors
| Type | Name | Description |
|---|---|---|
| input BooleanInput | u1Coo | Cooling plant enable |
| input BooleanInput | u1Hea | Heating plant enable |
| input BooleanInput | u1Hrc_actual | HRC status |
| input RealInput | QChiWatReq_flow | CHW load [W] |
| input RealInput | QHeaWatReq_flow | HW load [W] |
| input RealInput | TChiWatHrcLvg | HRC leaving CHW temperature [K] |
| input RealInput | THeaWatHrcLvg | HRC leaving HW temperature [K] |
| input BooleanInput | u1CooHrc | HRC control mode command: true for cooling, false for heating |
| output BooleanOutput | y1 | Enable command |
| output BooleanOutput | y1SetMod | Enable mode setting |
Modelica definition
block Enable
"Heat recovery chiller and HRC CHW and HW pumps enable"
parameter Real TChiWatSup_min(
final min=273.15,
start=4 + 273.15,
final unit="K",
displayUnit="degC")
"Minimum allowable CHW supply temperature";
parameter Real THeaWatSup_max(
final min=273.15,
start=60 + 273.15,
final unit="K",
displayUnit="degC")
"Maximum allowable HW supply temperature";
parameter Real capCoo_min(
final min=0,
final unit="W")
"Minimum cooling capacity below which cycling occurs";
parameter Real capHea_min(
final min=0,
final unit="W")
"Minimum heating capacity below which cycling occurs";
parameter Real dtRun(
final min=0,
final unit="s")=15 * 60
"Minimum runtime of enable and disable states";
parameter Real dtLoa(
final min=0,
final unit="s")=10 * 60
"Runtime with sufficient load before enabling";
parameter Real dtTem1(
final min=0,
final unit="s")=3 * 60
"Runtime with first temperature threshold exceeded before disabling";
parameter Real dtTem2(
final min=0,
final unit="s")=1 * 60
"Runtime with second temperature threshold exceeded before disabling";
Buildings.Controls.OBC.CDL.Interfaces.BooleanInput u1Coo
"Cooling plant enable";
Buildings.Controls.OBC.CDL.Interfaces.BooleanInput u1Hea
"Heating plant enable";
Buildings.Controls.OBC.CDL.Interfaces.BooleanInput u1Hrc_actual
"HRC status";
Buildings.Controls.OBC.CDL.Interfaces.RealInput QChiWatReq_flow(
final unit="W")
"CHW load";
Buildings.Controls.OBC.CDL.Interfaces.RealInput QHeaWatReq_flow(
final unit="W")
"HW load";
Buildings.Controls.OBC.CDL.Interfaces.RealInput TChiWatHrcLvg(
final unit="K",
displayUnit="degC")
"HRC leaving CHW temperature";
Buildings.Controls.OBC.CDL.Interfaces.RealInput THeaWatHrcLvg(
final unit="K",
displayUnit="degC")
"HRC leaving HW temperature";
Buildings.Controls.OBC.CDL.Interfaces.BooleanInput u1CooHrc
"HRC control mode command: true for cooling, false for heating";
Buildings.Controls.OBC.CDL.Interfaces.BooleanOutput y1
"Enable command";
Buildings.Controls.OBC.CDL.Logical.Pre preEna
"Left limit (in discrete-time) of enable signal";
Buildings.Controls.OBC.CDL.Logical.Timer timCooEna(
final t=dtRun)
"Return true if cooling plant has been enabled for specified duration";
Buildings.Controls.OBC.CDL.Logical.Not dis
"Return true if disabled";
Buildings.Controls.OBC.CDL.Logical.Timer runDis(
final t=dtRun)
"Return true if system has been disabled for specified duration";
Buildings.Controls.OBC.CDL.Logical.Timer timHeaEna(
final t=dtRun)
"Return true if heating plant has been enabled for specified duration";
Buildings.Controls.OBC.CDL.Reals.GreaterThreshold higLoaCoo(
final t=capCoo_min,
h=1E-4 * capCoo_min)
"Compare CHW load to cycling limit (hysteresis is to avoid chattering with some simulators)";
Buildings.Controls.OBC.CDL.Reals.GreaterThreshold higLoaHea(
final t=capHea_min,
h=1E-4 * capHea_min)
"Compare HW load to cycling limit (hysteresis is to avoid chattering with some simulators)";
Buildings.Controls.OBC.CDL.Reals.LessThreshold lowTChiWatLvg1(
final t=TChiWatSup_min + 1)
"Return true if first temperature limit exceeded";
Buildings.Controls.OBC.CDL.Reals.GreaterThreshold higTHeaWatLvg1(
final t=THeaWatSup_max - 1.5)
"Return true if first temperature limit exceeded";
Buildings.Controls.OBC.CDL.Reals.GreaterThreshold higTHeaWatLvg2(
final t=THeaWatSup_max)
"Return true if second temperature limit exceeded";
Buildings.Controls.OBC.CDL.Reals.LessThreshold lowTChiWatLvg2(
final t=TChiWatSup_min)
"Return true if second temperature limit exceeded";
Buildings.Controls.OBC.CDL.Logical.Timer timTHeaWatLvg1(
final t=dtTem1)
"Return true if threshold exceeded for specified duration";
Buildings.Controls.OBC.CDL.Logical.Timer timTHeaWatLvg2(
final t=dtTem2)
"Return true if threshold exceeded for specified duration";
Buildings.Controls.OBC.CDL.Logical.Timer timTChiWatLvg1(
final t=dtTem1)
"Return true if threshold exceeded for specified duration";
Buildings.Controls.OBC.CDL.Logical.Timer timTChiWatLvg2(
final t=dtTem2)
"Return true if threshold exceeded for specified duration";
Buildings.Controls.OBC.CDL.Logical.Timer timLoaCoo(
final t=dtLoa)
"Return true if threshold exceeded for specified duration";
Buildings.Controls.OBC.CDL.Logical.Timer timLoaHea(
final t=dtLoa)
"Return true if threshold exceeded for specified duration";
Buildings.Controls.OBC.CDL.Logical.MultiAnd allEna(
nin=5)
"All enable conditions met";
Buildings.Controls.OBC.CDL.Logical.MultiOr anyDis(
nin=5)
"Any disable condition met";
Buildings.Controls.OBC.CDL.Logical.Not disCoo
"Return true if cooling plant disabled";
Buildings.Controls.OBC.CDL.Logical.Not disHea
"Return true if heating plant disabled";
Buildings.Controls.OBC.CDL.Reals.LessThreshold lowLoaCoo(
final t=capCoo_min,
h=1E-4 * capCoo_min)
"Compare CHW load to cycling limit (hysteresis is to avoid chattering with some simulators)";
Buildings.Controls.OBC.CDL.Reals.LessThreshold lowLoaHea(
final t=capHea_min,
h=1E-4 * capHea_min)
"Compare HW load to cycling limit (hysteresis is to avoid chattering with some simulators)";
Buildings.Controls.OBC.CDL.Logical.Or anyLowLoa
"Any low load condition met";
Buildings.Controls.OBC.CDL.Logical.FallingEdge off
"Return true when HRC cycles off";
Buildings.Controls.OBC.CDL.Logical.And anyLowLoaAndOff
"Any low load condition met and HRC cycles off";
Buildings.Controls.OBC.CDL.Logical.And enaAndCoo
"HRC enabled in cooling mode";
Buildings.Controls.OBC.CDL.Logical.And enaAndHea
"HRC enabled in heating mode";
Buildings.Controls.OBC.CDL.Logical.Not hea
"True if heating control mode";
Buildings.Controls.OBC.CDL.Logical.Or anyTChiWatLvg
"Any leaving CHW temperature condition met";
Buildings.Controls.OBC.CDL.Logical.Or anyTHeaWatLvg
"Any leaving HW temperature condition met";
Buildings.Controls.OBC.CDL.Logical.And anyTChiWatLvgAndHea
"Any leaving CHW temperature condition met and HRC enabled in heating mode";
Buildings.Controls.OBC.CDL.Logical.And anyTHeaWatLvgAndCoo
"Any leaving HW temperature condition met and HRC enabled in cooling mode";
Buildings.Controls.OBC.CDL.Logical.Latch enaDis
"Maintain true signal until disable condition met";
Buildings.Controls.OBC.CDL.Interfaces.BooleanOutput y1SetMod
"Enable mode setting";
Buildings.Controls.OBC.CDL.Logical.TrueDelay truDel(
delayTime=5)
"Delay so that mode setting is enabled prior to enabling the HRC";
Buildings.Controls.OBC.CDL.Logical.Edge edg
"Enable mode setting just before enabling the HRC";
equation
connect(preEna.y, dis.u);
connect(dis.y, runDis.u);
connect(u1Coo, timCooEna.u);
connect(u1Hea, timHeaEna.u);
connect(y1, preEna.u);
connect(QChiWatReq_flow, higLoaCoo.u);
connect(QHeaWatReq_flow, higLoaHea.u);
connect(TChiWatHrcLvg, lowTChiWatLvg1.u);
connect(THeaWatHrcLvg, higTHeaWatLvg1.u);
connect(TChiWatHrcLvg, lowTChiWatLvg2.u);
connect(THeaWatHrcLvg, higTHeaWatLvg2.u);
connect(higTHeaWatLvg1.y, timTHeaWatLvg1.u);
connect(higTHeaWatLvg2.y, timTHeaWatLvg2.u);
connect(lowTChiWatLvg1.y, timTChiWatLvg1.u);
connect(lowTChiWatLvg2.y, timTChiWatLvg2.u);
connect(higLoaCoo.y, timLoaCoo.u);
connect(higLoaHea.y, timLoaHea.u);
connect(timCooEna.passed, allEna.u[1]);
connect(timHeaEna.passed, allEna.u[2]);
connect(runDis.passed, allEna.u[3]);
connect(timLoaCoo.passed, allEna.u[4]);
connect(timLoaHea.passed, allEna.u[5]);
connect(u1Coo, disCoo.u);
connect(u1Hea, disHea.u);
connect(disCoo.y, anyDis.u[1]);
connect(disHea.y, anyDis.u[2]);
connect(QChiWatReq_flow, lowLoaCoo.u);
connect(QChiWatReq_flow, lowLoaHea.u);
connect(lowLoaCoo.y, anyLowLoa.u1);
connect(lowLoaHea.y, anyLowLoa.u2);
connect(off.y, anyLowLoaAndOff.u1);
connect(anyLowLoa.y, anyLowLoaAndOff.u2);
connect(anyLowLoaAndOff.y, anyDis.u[3]);
connect(u1CooHrc, hea.u);
connect(u1CooHrc, enaAndCoo.u2);
connect(hea.y, enaAndHea.u2);
connect(timTHeaWatLvg1.passed, anyTHeaWatLvg.u1);
connect(timTChiWatLvg1.passed, anyTChiWatLvg.u1);
connect(timTChiWatLvg2.passed, anyTChiWatLvg.u2);
connect(timTHeaWatLvg2.passed, anyTHeaWatLvg.u2);
connect(anyTChiWatLvg.y, anyTChiWatLvgAndHea.u2);
connect(anyTChiWatLvgAndHea.y, anyDis.u[4]);
connect(anyTHeaWatLvgAndCoo.y, anyDis.u[5]);
connect(allEna.y, enaDis.u);
connect(anyDis.y, enaDis.clr);
connect(enaDis.y, truDel.u);
connect(truDel.y, y1);
connect(enaDis.y, edg.u);
connect(edg.y, y1SetMod);
connect(u1Hrc_actual, off.u);
connect(preEna.y, enaAndCoo.u1);
connect(preEna.y, enaAndHea.u1);
connect(enaAndCoo.y, anyTHeaWatLvgAndCoo.u1);
connect(anyTHeaWatLvg.y, anyTHeaWatLvgAndCoo.u2);
connect(enaAndHea.y, anyTChiWatLvgAndHea.u1);
end Enable;
Buildings.Templates.Plants.Controls.HeatRecoveryChillers.ModeControl
Mode control and setpoint selection
Information
Mode control
If the following equation is true prior to enabling the HRC, set the control mode to heating. Otherwise, set the control mode to cooling.
QChiWatReq_flow > QHeaWat_flow * (1 - 1 / COPHea_nominal)
Write mode via the chiller’s BACnet interface prior to sending the chiller an enable command.
Setpoint
When the control mode is cooling, the active setpoint shall be the CHW supply temperature setpoint. When the control mode is heating, the active setpoint shall be the HW supply temperature setpoint.
Details
The condition "prior to enabling the HRC" is evaluated in the block Buildings.Templates.Plants.Controls.HeatRecoveryChillers.Enable.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Information provided by designer | |||
| Real | COPHea_nominal | Heating COP at design heating conditions [1] | |
Connectors
| Type | Name | Description |
|---|---|---|
| input BooleanInput | u1SetMod | Enable mode setting |
| input RealInput | QChiWatReq_flow | CHW load [W] |
| input RealInput | QHeaWatReq_flow | HW load [W] |
| input RealInput | TChiWatSupSet | Active CHW supply temperature setpoint [K] |
| input RealInput | THeaWatSupSet | Active HW supply temperature setpoint [K] |
| output BooleanOutput | y1Coo | Mode command: true for cooling, false for heating |
| output RealOutput | TSupSet | Active supply temperature setpoint [K] |
Modelica definition
block ModeControl
"Mode control and setpoint selection"
parameter Real COPHea_nominal(
final min=1.1,
final unit="1")
"Heating COP at design heating conditions";
Buildings.Controls.OBC.CDL.Interfaces.BooleanInput u1SetMod
"Enable mode setting";
Buildings.Controls.OBC.CDL.Interfaces.RealInput QChiWatReq_flow(
final unit="W")
"CHW load";
Buildings.Controls.OBC.CDL.Interfaces.RealInput QHeaWatReq_flow(
final unit="W")
"HW load";
Buildings.Controls.OBC.CDL.Interfaces.RealInput TChiWatSupSet(
final unit="K",
displayUnit="degC")
"Active CHW supply temperature setpoint";
Buildings.Controls.OBC.CDL.Interfaces.RealInput THeaWatSupSet(
final unit="K",
displayUnit="degC")
"Active HW supply temperature setpoint";
Buildings.Controls.OBC.CDL.Interfaces.BooleanOutput y1Coo
"Mode command: true for cooling, false for heating";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput TSupSet(
final unit="K",
displayUnit="degC")
"Active supply temperature setpoint";
Buildings.Controls.OBC.CDL.Reals.MultiplyByParameter QEvaHea_flow(
final k=1 - 1 / COPHea_nominal)
"Compute evaporator heat flow rate in heating mode";
Buildings.Controls.OBC.CDL.Reals.Less les
"True (cooling) if CHW load lower than evaporator heat flow rate in heating mode";
Buildings.Controls.OBC.CDL.Reals.Switch selTSupSet
"Select supply temperature setpoint";
Buildings.Controls.OBC.CDL.Logical.Switch setMod
"Set mode if mode setting enabled, otherwise reuse previous mode";
Buildings.Controls.OBC.CDL.Logical.Pre preMod
"Previous mode setting";
equation
connect(QHeaWatReq_flow, QEvaHea_flow.u);
connect(QChiWatReq_flow, les.u1);
connect(QEvaHea_flow.y, les.u2);
connect(TChiWatSupSet, selTSupSet.u1);
connect(THeaWatSupSet, selTSupSet.u3);
connect(selTSupSet.y, TSupSet);
connect(u1SetMod, setMod.u2);
connect(setMod.y, y1Coo);
connect(les.y, setMod.u1);
connect(y1Coo, preMod.u);
connect(preMod.y, setMod.u3);
connect(y1Coo, selTSupSet.u2);
end ModeControl;