Buildings.Fluid.Movers
Package with fan and pump models
Information
This package contains component models for fans and pumps.Extends from Modelica.Icons.Package (Icon for standard packages).
Package Content
| Name | Description |
|---|---|
 UsersGuide
|
User's Guide |
 FlowControlled_dp
|
Fan or pump with ideally controlled head dp as input signal |
 FlowControlled_m_flow
|
Fan or pump with ideally controlled mass flow rate as input signal |
 SpeedControlled_Nrpm
|
Fan or pump with ideally controlled speed Nrpm as input signal |
 SpeedControlled_y
|
Fan or pump with ideally controlled normalized speed y as input signal |
 Data
|
Package containing data for real pumps/fans |
 Examples
|
Collection of models that illustrate model use and test models |
| Validation
|
Collection of validation models |
 BaseClasses
|
Package with base classes for Buildings.Fluid.Movers |
Buildings.Fluid.Movers.FlowControlled_dp
Fan or pump with ideally controlled head dp as input signal
Information
This model describes a fan or pump with prescribed head.
The input connector provides the difference between
outlet minus inlet pressure.
The efficiency of the device is computed based
on the efficiency and pressure curves that are defined
in record per, which is of type
Buildings.Fluid.Movers.SpeedControlled_Nrpm.
Main equations
See the User's Guide.
Typical use and important parameters
If use_inputFilter=true, then the parameter dp_nominal is
used to normalize the filter. This is used to improve the numerics of the transient response.
The actual pressure raise of the mover at steady-state is independent
of the value of dp_nominal. It is recommended to set
dp_nominal to approximately the pressure raise that the mover has during
full speed.
Options
Parameter prescribeSystemPressure
can be used to control the mover such that the pressure
difference set point is obtained across two points
in the system, instead of across the fan.
This allows an efficient implementation of
static pressure reset controllers.
A measurement of the pressure difference between the
two points in system then needs to be connected
to RealInput dpMea.
This functionality is demonstrated in
Buildings.Fluid.Movers.Validation.FlowControlled_dpSystem.
Extends from Buildings.Fluid.Movers.BaseClasses.PartialFlowMachine (Partial model to interface fan or pump models with the medium).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| replaceable package Medium | PartialMedium | Medium in the component | |
| Generic | per | redeclare parameter Building... | Record with performance data |
| Boolean | computePowerUsingSimilarityLaws | per.havePressureCurve | = true, compute power exactly, using similarity laws. Otherwise approximate. |
| Boolean | addPowerToMedium | true | Set to false to avoid any power (=heat and flow work) being added to medium (may give simpler equations) |
| Boolean | nominalValuesDefineDefaultPressureCurve | false | Set to true to avoid warning if m_flow_nominal and dp_nominal are used to construct the default pressure curve |
| PressureDifference | constantHead | dp_nominal | Constant pump head, used when inputType=Constant [Pa] |
| PressureDifference | heads[:] | dp_nominal*{(per.speeds[i]/p... | Vector of head set points, used when inputType=Stages [Pa] |
| Nominal condition | |||
| MassFlowRate | m_flow_nominal | m_flow_nominal(final min=Mod... | Nominal mass flow rate [kg/s] |
| PressureDifference | dp_nominal | if rho_default < 500 then 50... | Nominal pressure raise, used to normalized the filter if use_inputFilter=true, to set default values of constantHead and heads, and and for default pressure curve if not specified in record per [Pa] |
| Control | |||
| InputType | inputType | Buildings.Fluid.Types.InputT... | Control input type |
| Dynamics | |||
| Conservation equations | |||
| Dynamics | energyDynamics | Modelica.Fluid.Types.Dynamic... | Type of energy balance: dynamic (3 initialization options) or steady state |
| Nominal condition | |||
| Time | tau | 1 | Time constant of fluid volume for nominal flow, used if energy or mass balance is dynamic [s] |
| Filtered speed | |||
| Boolean | use_inputFilter | true | = true, if speed is filtered with a 2nd order CriticalDamping filter |
| Time | riseTime | 30 | Rise time of the filter (time to reach 99.6 % of the speed) [s] |
| Init | init | Modelica.Blocks.Types.Init.I... | Type of initialization (no init/steady state/initial state/initial output) |
| PressureDifference | dp_start | 0 | Initial value of pressure raise [Pa] |
| Initialization | |||
| AbsolutePressure | p_start | Medium.p_default | Start value of pressure [Pa] |
| Temperature | T_start | Medium.T_default | Start value of temperature [K] |
| MassFraction | X_start[Medium.nX] | Medium.X_default | Start value of mass fractions m_i/m [kg/kg] |
| ExtraProperty | C_start[Medium.nC] | fill(0, Medium.nC) | Start value of trace substances |
| ExtraProperty | C_nominal[Medium.nC] | fill(1E-2, Medium.nC) | Nominal value of trace substances. (Set to typical order of magnitude.) |
| Assumptions | |||
| Boolean | allowFlowReversal | true | = false to simplify equations, assuming, but not enforcing, no flow reversal |
| Advanced | |||
| MassFlowRate | m_flow_small | 1E-4*abs(m_flow_nominal) | Small mass flow rate for regularization of zero flow [kg/s] |
| Boolean | prescribeSystemPressure | false | =true, to control mover such that pressure difference is obtained across two remote points in system |
| Diagnostics | |||
| Boolean | show_T | false | = true, if actual temperature at port is computed |
Connectors
| Type | Name | Description |
|---|---|---|
| FluidPort_a | port_a | Fluid connector a (positive design flow direction is from port_a to port_b) |
| FluidPort_b | port_b | Fluid connector b (positive design flow direction is from port_a to port_b) |
| input IntegerInput | stage | Stage input signal for the pressure head |
| output RealOutput | y_actual | Actual normalised pump speed that is used for computations [1] |
| output RealOutput | P | Electrical power consumed [W] |
| HeatPort_a | heatPort | Heat dissipation to environment |
| input RealInput | dpMea | Measurement of pressure difference between two points where the set point should be obtained [Pa] |
| input RealInput | dp_in | Prescribed pressure rise [Pa] |
| output RealOutput | dp_actual | Pressure difference between the mover inlet and outlet [Pa] |
Modelica definition
model FlowControlled_dp
"Fan or pump with ideally controlled head dp as input signal"
extends Buildings.Fluid.Movers.BaseClasses.PartialFlowMachine(
final preVar=Buildings.Fluid.Movers.BaseClasses.Types.PrescribedVariable.PressureDifference,
final computePowerUsingSimilarityLaws=per.havePressureCurve,
preSou(dp_start=dp_start, control_dp= not prescribeSystemPressure),
final stageInputs(each final unit="Pa") = heads,
final constInput(final unit="Pa") = constantHead,
filter(
final y_start=dp_start,
u(final unit="Pa"),
y(final unit="Pa"),
x(each nominal=dp_nominal),
u_nominal=dp_nominal),
eff(
per(
final pressure = if per.havePressureCurve then
per.pressure
else
Buildings.Fluid.Movers.BaseClasses.Characteristics.flowParameters(
V_flow = {i/(nOri-1)*2.0*m_flow_nominal/rho_default for i in 0:(nOri-1)},
dp = {i/(nOri-1)*2.0*dp_nominal for i in (nOri-1):-1:0}),
final use_powerCharacteristic = if per.havePressureCurve then per.use_powerCharacteristic else false),
r_N(start=if abs(dp_nominal) > 1E-8 then dp_start/dp_nominal else 0)));
parameter Modelica.Units.SI.PressureDifference dp_start(
min=0,
displayUnit="Pa") = 0 "Initial value of pressure raise";
// For air, we set dp_nominal = 600 as default, for water we set 10000
parameter Modelica.Units.SI.PressureDifference dp_nominal(
min=0,
displayUnit="Pa") = if rho_default < 500 then 500 else 10000 "Nominal pressure raise, used to normalized the filter if use_inputFilter=true,
to set default values of constantHead and heads, and
and for default pressure curve if not specified in record per";
parameter Modelica.Units.SI.PressureDifference constantHead(
min=0,
displayUnit="Pa") = dp_nominal
"Constant pump head, used when inputType=Constant";
// By default, set heads proportional to sqrt(speed/speed_nominal)
parameter Modelica.Units.SI.PressureDifference[:] heads(
each min=0,
each displayUnit="Pa") = dp_nominal*{(per.speeds[i]/per.speeds[end])^2 for
i in 1:size(per.speeds, 1)}
"Vector of head set points, used when inputType=Stages";
parameter Boolean prescribeSystemPressure = false
"=true, to control mover such that pressure difference is obtained across two remote points in system";
Modelica.Blocks.Interfaces.RealInput dpMea(
final quantity="PressureDifference",
final displayUnit="Pa",
final unit="Pa")=gain.u if prescribeSystemPressure
"Measurement of pressure difference between two points where the set point should be obtained";
Modelica.Blocks.Interfaces.RealInput dp_in(final unit="Pa")
if inputType == Buildings.Fluid.Types.InputType.Continuous
"Prescribed pressure rise";
Modelica.Blocks.Interfaces.RealOutput dp_actual(final unit="Pa")
"Pressure difference between the mover inlet and outlet";
protected
Modelica.Blocks.Math.Gain gain(final k=-1);
equation
assert(inputSwitch.u >= -1E-3,
"Pressure set point for mover cannot be negative. Obtained dp = " + String(inputSwitch.u));
if use_inputFilter then
connect(filter.y, gain.u);
else
connect(inputSwitch.y, gain.u);
end if;
connect(inputSwitch.u, dp_in);
connect(preSou.dp_in, gain.y);
connect(senRelPre.p_rel, dp_actual);
end FlowControlled_dp;
Buildings.Fluid.Movers.FlowControlled_m_flow
Fan or pump with ideally controlled mass flow rate as input signal
Information
This model describes a fan or pump with prescribed mass flow rate.
The efficiency of the device is computed based
on the efficiency and pressure curves that are defined
in record per, which is of type
Buildings.Fluid.Movers.SpeedControlled_Nrpm.
See the User's Guide for more information.
Extends from Buildings.Fluid.Movers.BaseClasses.PartialFlowMachine (Partial model to interface fan or pump models with the medium).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| replaceable package Medium | PartialMedium | Medium in the component | |
| Generic | per | redeclare parameter Building... | Record with performance data |
| Boolean | computePowerUsingSimilarityLaws | per.havePressureCurve | = true, compute power exactly, using similarity laws. Otherwise approximate. |
| Boolean | addPowerToMedium | true | Set to false to avoid any power (=heat and flow work) being added to medium (may give simpler equations) |
| Boolean | nominalValuesDefineDefaultPressureCurve | false | Set to true to avoid warning if m_flow_nominal and dp_nominal are used to construct the default pressure curve |
| MassFlowRate | constantMassFlowRate | m_flow_nominal | Constant pump mass flow rate, used when inputType=Constant [kg/s] |
| MassFlowRate | massFlowRates[:] | m_flow_nominal*{per.speeds[i... | Vector of mass flow rate set points, used when inputType=Stage [kg/s] |
| Nominal condition | |||
| MassFlowRate | m_flow_nominal | m_flow_nominal(final min=Mod... | Nominal mass flow rate [kg/s] |
| PressureDifference | dp_nominal | if rho_default < 500 then 50... | Nominal pressure raise, used for default pressure curve if not specified in record per [Pa] |
| Control | |||
| InputType | inputType | Buildings.Fluid.Types.InputT... | Control input type |
| Dynamics | |||
| Conservation equations | |||
| Dynamics | energyDynamics | Modelica.Fluid.Types.Dynamic... | Type of energy balance: dynamic (3 initialization options) or steady state |
| Nominal condition | |||
| Time | tau | 1 | Time constant of fluid volume for nominal flow, used if energy or mass balance is dynamic [s] |
| Filtered speed | |||
| Boolean | use_inputFilter | true | = true, if speed is filtered with a 2nd order CriticalDamping filter |
| Time | riseTime | 30 | Rise time of the filter (time to reach 99.6 % of the speed) [s] |
| Init | init | Modelica.Blocks.Types.Init.I... | Type of initialization (no init/steady state/initial state/initial output) |
| MassFlowRate | m_flow_start | 0 | Initial value of mass flow rate [kg/s] |
| Initialization | |||
| AbsolutePressure | p_start | Medium.p_default | Start value of pressure [Pa] |
| Temperature | T_start | Medium.T_default | Start value of temperature [K] |
| MassFraction | X_start[Medium.nX] | Medium.X_default | Start value of mass fractions m_i/m [kg/kg] |
| ExtraProperty | C_start[Medium.nC] | fill(0, Medium.nC) | Start value of trace substances |
| ExtraProperty | C_nominal[Medium.nC] | fill(1E-2, Medium.nC) | Nominal value of trace substances. (Set to typical order of magnitude.) |
| Assumptions | |||
| Boolean | allowFlowReversal | true | = false to simplify equations, assuming, but not enforcing, no flow reversal |
| Advanced | |||
| MassFlowRate | m_flow_small | 1E-4*abs(m_flow_nominal) | Small mass flow rate for regularization of zero flow [kg/s] |
| Diagnostics | |||
| Boolean | show_T | false | = true, if actual temperature at port is computed |
Connectors
| Type | Name | Description |
|---|---|---|
| FluidPort_a | port_a | Fluid connector a (positive design flow direction is from port_a to port_b) |
| FluidPort_b | port_b | Fluid connector b (positive design flow direction is from port_a to port_b) |
| input IntegerInput | stage | Stage input signal for the pressure head |
| output RealOutput | y_actual | Actual normalised pump speed that is used for computations [1] |
| output RealOutput | P | Electrical power consumed [W] |
| HeatPort_a | heatPort | Heat dissipation to environment |
| input RealInput | m_flow_in | Prescribed mass flow rate [kg/s] |
| output RealOutput | m_flow_actual | Actual mass flow rate [kg/s] |
Modelica definition
model FlowControlled_m_flow
"Fan or pump with ideally controlled mass flow rate as input signal"
extends Buildings.Fluid.Movers.BaseClasses.PartialFlowMachine(
final preVar=Buildings.Fluid.Movers.BaseClasses.Types.PrescribedVariable.FlowRate,
final computePowerUsingSimilarityLaws=per.havePressureCurve,
final stageInputs(each final unit="kg/s")=massFlowRates,
final constInput(final unit="kg/s")=constantMassFlowRate,
filter(
final y_start=m_flow_start,
u(final unit="kg/s"),
y(final unit="kg/s"),
x(each nominal=m_flow_nominal),
u_nominal=m_flow_nominal),
eff(
per(
final pressure = if per.havePressureCurve then
per.pressure
else
Buildings.Fluid.Movers.BaseClasses.Characteristics.flowParameters(
V_flow = {i/(nOri-1)*2.0*m_flow_nominal/rho_default for i in 0:(nOri-1)},
dp = {i/(nOri-1)*2.0*dp_nominal for i in (nOri-1):-1:0}),
final use_powerCharacteristic = if per.havePressureCurve then per.use_powerCharacteristic else false),
r_N(start=if abs(m_flow_nominal) > 1E-8 then m_flow_start/m_flow_nominal else 0)),
preSou(m_flow_start=m_flow_start));
// For air, we set dp_nominal = 600 as default, for water we set 10000
parameter Modelica.Units.SI.PressureDifference dp_nominal(
min=0,
displayUnit="Pa") = if rho_default < 500 then 500 else 10000
"Nominal pressure raise, used for default pressure curve if not specified in record per";
parameter Modelica.Units.SI.MassFlowRate m_flow_start(min=0) = 0
"Initial value of mass flow rate";
parameter Modelica.Units.SI.MassFlowRate constantMassFlowRate=m_flow_nominal
"Constant pump mass flow rate, used when inputType=Constant";
// By default, set massFlowRates proportional to (speed/speed_nominal)
parameter Modelica.Units.SI.MassFlowRate[:] massFlowRates=m_flow_nominal*{per.speeds[
i]/per.speeds[end] for i in 1:size(per.speeds, 1)}
"Vector of mass flow rate set points, used when inputType=Stage";
Modelica.Blocks.Interfaces.RealInput m_flow_in(
final unit="kg/s",
nominal=m_flow_nominal)
if inputType == Buildings.Fluid.Types.InputType.Continuous
"Prescribed mass flow rate";
Modelica.Blocks.Interfaces.RealOutput m_flow_actual(
final unit="kg/s",
nominal=m_flow_nominal) "Actual mass flow rate";
equation
if use_inputFilter then
connect(filter.y, m_flow_actual);
connect(filter.y, preSou.m_flow_in);
else
connect(inputSwitch.y, m_flow_actual);
connect(inputSwitch.y, preSou.m_flow_in);
end if;
connect(inputSwitch.u, m_flow_in);
end FlowControlled_m_flow;
Buildings.Fluid.Movers.SpeedControlled_Nrpm
Fan or pump with ideally controlled speed Nrpm as input signal
Information
This model describes a fan or pump with prescribed speed in revolutions per minute. The head is computed based on the performance curve that take as an argument the actual volume flow rate divided by the maximum flow rate and the relative speed of the fan. The efficiency of the device is computed based on the efficiency curves that take as an argument the actual volume flow rate divided by the maximum possible volume flow rate, or based on the motor performance curves.
See the User's Guide for more information.
Extends from Buildings.Fluid.Movers.BaseClasses.PartialFlowMachine (Partial model to interface fan or pump models with the medium).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| replaceable package Medium | PartialMedium | Medium in the component | |
| Generic | per | redeclare parameter Building... | Record with performance data |
| Boolean | computePowerUsingSimilarityLaws | true | = true, compute power exactly, using similarity laws. Otherwise approximate. |
| Boolean | addPowerToMedium | true | Set to false to avoid any power (=heat and flow work) being added to medium (may give simpler equations) |
| Boolean | nominalValuesDefineDefaultPressureCurve | false | Set to true to avoid warning if m_flow_nominal and dp_nominal are used to construct the default pressure curve |
| Nominal condition | |||
| MassFlowRate | m_flow_nominal | max(per.pressure.V_flow)*rho... | Nominal mass flow rate [kg/s] |
| Control | |||
| InputType | inputType | Buildings.Fluid.Types.InputT... | Control input type |
| Dynamics | |||
| Conservation equations | |||
| Dynamics | energyDynamics | Modelica.Fluid.Types.Dynamic... | Type of energy balance: dynamic (3 initialization options) or steady state |
| Nominal condition | |||
| Time | tau | 1 | Time constant of fluid volume for nominal flow, used if energy or mass balance is dynamic [s] |
| Filtered speed | |||
| Boolean | use_inputFilter | true | = true, if speed is filtered with a 2nd order CriticalDamping filter |
| Time | riseTime | 30 | Rise time of the filter (time to reach 99.6 % of the speed) [s] |
| Init | init | Modelica.Blocks.Types.Init.I... | Type of initialization (no init/steady state/initial state/initial output) |
| Real | y_start | 0 | Initial value of speed [1] |
| Initialization | |||
| AbsolutePressure | p_start | Medium.p_default | Start value of pressure [Pa] |
| Temperature | T_start | Medium.T_default | Start value of temperature [K] |
| MassFraction | X_start[Medium.nX] | Medium.X_default | Start value of mass fractions m_i/m [kg/kg] |
| ExtraProperty | C_start[Medium.nC] | fill(0, Medium.nC) | Start value of trace substances |
| ExtraProperty | C_nominal[Medium.nC] | fill(1E-2, Medium.nC) | Nominal value of trace substances. (Set to typical order of magnitude.) |
| Assumptions | |||
| Boolean | allowFlowReversal | true | = false to simplify equations, assuming, but not enforcing, no flow reversal |
| Advanced | |||
| MassFlowRate | m_flow_small | 1E-4*abs(m_flow_nominal) | Small mass flow rate for regularization of zero flow [kg/s] |
| Diagnostics | |||
| Boolean | show_T | false | = true, if actual temperature at port is computed |
Connectors
| Type | Name | Description |
|---|---|---|
| FluidPort_a | port_a | Fluid connector a (positive design flow direction is from port_a to port_b) |
| FluidPort_b | port_b | Fluid connector b (positive design flow direction is from port_a to port_b) |
| input IntegerInput | stage | Stage input signal for the pressure head |
| output RealOutput | y_actual | Actual normalised pump speed that is used for computations [1] |
| output RealOutput | P | Electrical power consumed [W] |
| HeatPort_a | heatPort | Heat dissipation to environment |
| input RealInput | Nrpm | Prescribed rotational speed [rev/min] |
Modelica definition
model SpeedControlled_Nrpm
"Fan or pump with ideally controlled speed Nrpm as input signal"
extends Buildings.Fluid.Movers.BaseClasses.PartialFlowMachine(
final preVar=Buildings.Fluid.Movers.BaseClasses.Types.PrescribedVariable.Speed,
final nominalValuesDefineDefaultPressureCurve=false,
final computePowerUsingSimilarityLaws=true,
final m_flow_nominal = max(per.pressure.V_flow)*rho_default,
final stageInputs(each final unit="1") = per.speeds,
final constInput(final unit="1") = per.constantSpeed,
filter(
final y_start=y_start,
u(final unit="1"),
y(final unit="1")),
eff(
per(final pressure = per.pressure,
final use_powerCharacteristic = per.use_powerCharacteristic),
r_N(start=y_start)),
gaiSpe(u(final unit="rev/min"),
final k=1/per.speed_rpm_nominal));
parameter Real y_start(min=0, max=1, unit="1")=0 "Initial value of speed";
Modelica.Blocks.Interfaces.RealInput Nrpm(final unit="rev/min")
if inputType == Buildings.Fluid.Types.InputType.Continuous
"Prescribed rotational speed";
protected
Modelica.Blocks.Math.Gain gain(final k=-1) "Pressure gain";
initial equation
assert(per.havePressureCurve,
"SpeedControlled_Nrpm model requires to set the pressure vs. flow rate curve in record 'per'.");
equation
connect(Nrpm, gaiSpe.u);
connect(gaiSpe.y, inputSwitch.u);
connect(eff.dp, gain.u);
connect(gain.y, preSou.dp_in);
if use_inputFilter then
connect(filter.y, eff.y_in);
else
connect(inputSwitch.y, eff.y_in);
end if;
end SpeedControlled_Nrpm;
Buildings.Fluid.Movers.SpeedControlled_y
Fan or pump with ideally controlled normalized speed y as input signal
Information
This model describes a fan or pump with prescribed normalized speed. The input connector provides the normalized rotational speed (between 0 and 1). The head is computed based on the performance curve that take as an argument the actual volume flow rate divided by the maximum flow rate and the relative speed of the fan. The efficiency of the device is computed based on the efficiency curves that take as an argument the actual volume flow rate divided by the maximum possible volume flow rate, or based on the motor performance curves.
See the User's Guide for more information.
Extends from Buildings.Fluid.Movers.BaseClasses.PartialFlowMachine (Partial model to interface fan or pump models with the medium).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| replaceable package Medium | PartialMedium | Medium in the component | |
| Generic | per | redeclare parameter Building... | Record with performance data |
| Boolean | computePowerUsingSimilarityLaws | true | = true, compute power exactly, using similarity laws. Otherwise approximate. |
| Boolean | addPowerToMedium | true | Set to false to avoid any power (=heat and flow work) being added to medium (may give simpler equations) |
| Boolean | nominalValuesDefineDefaultPressureCurve | false | Set to true to avoid warning if m_flow_nominal and dp_nominal are used to construct the default pressure curve |
| Nominal condition | |||
| MassFlowRate | m_flow_nominal | max(per.pressure.V_flow)*rho... | Nominal mass flow rate [kg/s] |
| Control | |||
| InputType | inputType | Buildings.Fluid.Types.InputT... | Control input type |
| Dynamics | |||
| Conservation equations | |||
| Dynamics | energyDynamics | Modelica.Fluid.Types.Dynamic... | Type of energy balance: dynamic (3 initialization options) or steady state |
| Nominal condition | |||
| Time | tau | 1 | Time constant of fluid volume for nominal flow, used if energy or mass balance is dynamic [s] |
| Filtered speed | |||
| Boolean | use_inputFilter | true | = true, if speed is filtered with a 2nd order CriticalDamping filter |
| Time | riseTime | 30 | Rise time of the filter (time to reach 99.6 % of the speed) [s] |
| Init | init | Modelica.Blocks.Types.Init.I... | Type of initialization (no init/steady state/initial state/initial output) |
| Real | y_start | 0 | Initial value of speed [1] |
| Initialization | |||
| AbsolutePressure | p_start | Medium.p_default | Start value of pressure [Pa] |
| Temperature | T_start | Medium.T_default | Start value of temperature [K] |
| MassFraction | X_start[Medium.nX] | Medium.X_default | Start value of mass fractions m_i/m [kg/kg] |
| ExtraProperty | C_start[Medium.nC] | fill(0, Medium.nC) | Start value of trace substances |
| ExtraProperty | C_nominal[Medium.nC] | fill(1E-2, Medium.nC) | Nominal value of trace substances. (Set to typical order of magnitude.) |
| Assumptions | |||
| Boolean | allowFlowReversal | true | = false to simplify equations, assuming, but not enforcing, no flow reversal |
| Advanced | |||
| MassFlowRate | m_flow_small | 1E-4*abs(m_flow_nominal) | Small mass flow rate for regularization of zero flow [kg/s] |
| Diagnostics | |||
| Boolean | show_T | false | = true, if actual temperature at port is computed |
Connectors
| Type | Name | Description |
|---|---|---|
| FluidPort_a | port_a | Fluid connector a (positive design flow direction is from port_a to port_b) |
| FluidPort_b | port_b | Fluid connector b (positive design flow direction is from port_a to port_b) |
| input IntegerInput | stage | Stage input signal for the pressure head |
| output RealOutput | y_actual | Actual normalised pump speed that is used for computations [1] |
| output RealOutput | P | Electrical power consumed [W] |
| HeatPort_a | heatPort | Heat dissipation to environment |
| input RealInput | y | Constant normalized rotational speed [1] |
Modelica definition
model SpeedControlled_y
"Fan or pump with ideally controlled normalized speed y as input signal"
extends Buildings.Fluid.Movers.BaseClasses.PartialFlowMachine(
final preVar=Buildings.Fluid.Movers.BaseClasses.Types.PrescribedVariable.Speed,
final nominalValuesDefineDefaultPressureCurve=false,
final computePowerUsingSimilarityLaws=true,
final m_flow_nominal = max(per.pressure.V_flow)*rho_default,
final stageInputs(each final unit="1") = per.speeds,
final constInput(final unit="1") = per.constantSpeed,
filter(
final y_start=y_start,
u(final unit="1"),
y(final unit="1")),
eff(
per(final pressure = per.pressure,
final use_powerCharacteristic = per.use_powerCharacteristic),
r_N(start=y_start)),
gaiSpe(u(final unit="1"),
final k=1/per.speed_nominal));
parameter Real y_start(min=0, max=1, unit="1")=0 "Initial value of speed";
Modelica.Blocks.Interfaces.RealInput y(
unit="1")
if inputType == Buildings.Fluid.Types.InputType.Continuous
"Constant normalized rotational speed";
protected
Modelica.Blocks.Math.Gain gain(final k=-1) "Pressure gain";
initial equation
assert(per.havePressureCurve,
"SpeedControlled_y requires to set the pressure vs. flow rate curve in record 'per'.");
equation
connect(gaiSpe.u, y);
connect(gaiSpe.y, inputSwitch.u);
connect(eff.dp, gain.u);
connect(gain.y, preSou.dp_in);
if use_inputFilter then
connect(filter.y, eff.y_in);
else
connect(inputSwitch.y, eff.y_in);
end if;
end SpeedControlled_y;