modelStation_m_flow
Extends from BuildingSystems.Technologies.DistrictHeatingNetworks.EnergyTransferStations.BaseClasses.PartialStation.
Information
The station model uses the ambient air temperature to determine the set point for the supply temperature in the building (secondary loop). The exact temperature depends on the parameters Tsupply_max, Tsupply_min,factor_Tsupply of the tanhAmbience block.
This set temperature is used to determine the mass flow rate in the pump pumpDHN.
The building/zone tempearture input signal is used to determine the percentage of nominal mass flow rate that should be pumped by pumpHeating. The block externalIdealHeater extracts energy so that the fluid undergoes a temperature drop equal to the paremeter Tdrop.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Units.SI.Efficiency | eps (from PartialStation) | 0.9 | Heat exchanger effectiveness |
| Modelica.Units.SI.Temperature | TminDHN | 273.15 + 30 | Minimum return temperature in building's installation |
| Modelica.Units.SI.TemperatureDifference | Tdrop | 25 | Desired Temperature drop in building's installation |
| Real | eps_inst | 1 | Factor accountig per inneficiency of installation. Increase heat to be delivered |
| Modelica.Units.SI.Temperature | Tsupply_max | 273.15 + 90 | Maximum supply temperature in building |
| Modelica.Units.SI.Temperature | Tsupply_min | 273.15 + 70 | Minimum supply temperature in building |
| Real | factor_Tsupply | 7 | Un- or smooth changes of the supply set temperature. tanh((InSignal-SetValue)/factor) (notice, tanh(1)=0.7616 tanh(3)=0.9951) |
| Real | factor_m_flow | 0.05 | Un- or smooth changes of mass flow rate of the heating system. tanh((InSignal-SetValue)/factor) (notice, tanh(1)=0.7616 tanh(3)=0.9951) |
| Boolean | addPowerToMedium | false | Set to false to avoid any power in the pump model (=heat and flow work) being added to medium (may give simpler equations) |
| Assumptions | |||
| Boolean | allowFlowReversal (from PartialTwoPort) | true | = false to simplify equations, assuming, but not enforcing, no flow reversal |
| Nominal condition | |||
| Modelica.Units.SI.MassFlowRate | m_flow_nominal (from PartialTwoPortInterface) | Nominal mass flow rate | |
| Modelica.Units.SI.HeatFlowRate | Q_nominal | Nominal Heat power in the Heat Transfer Station | |
| Modelica.Units.SI.MassFlowRate | m_flow_nominalDHN | 1.05*m_flow_nominalHeating | Nominal mass flow rate |
| Modelica.Units.SI.Pressure | dp_nominalDHN | 40000 | Nominal pressure drop at the Heat Exchanger DHN loop |
| Modelica.Units.SI.MassFlowRate | m_flow_nominalHeating | Q_nominal/4182/Tdrop | Nominal mass flow rate |
| Modelica.Units.SI.Pressure | dp_nominalHeating | 40000 | Nominal pressure drop at the Heat Exchanger heating installation loop |
| Advanced | |||
| Modelica.Units.SI.MassFlowRate | m_flow_small (from PartialTwoPortInterface) | 1E-4*abs(m_flow_nominal) | Small mass flow rate for regularization of zero flow |
| Advanced › Diagnostics | |||
| Boolean | show_T (from PartialTwoPortInterface) | false | = true, if actual temperature at port is computed |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Fluid.Interfaces.FluidPort_a | port_a (from PartialTwoPort) | Fluid connector a (positive design flow direction is from port_a to port_b) | |
| Modelica.Fluid.Interfaces.FluidPort_b | port_b (from PartialTwoPort) | Fluid connector b (positive design flow direction is from port_a to port_b) | |
| Modelica.Blocks.Interfaces.RealInput | ambienceTAirRef (from PartialStation) | ||
| Modelica.Blocks.Interfaces.RealInput | zoneTAir (from PartialStation) | ||
| Modelica.Blocks.Interfaces.RealInput | Tset (from PartialStation) | Heating set temperature | |
| Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a | Radheat (from PartialStation) | ||
| Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a | Conheat (from PartialStation) |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Units.SI.MassFlowRate | m_flow (from PartialTwoPortInterface) | port_a.m_flow | Mass flow rate from port_a to port_b (m_flow > 0 is design flow direction) |
| Modelica.Units.SI.PressureDifference | dp (from PartialTwoPortInterface) | port_a.p - port_b.p | Pressure difference between port_a and port_b |
| Medium.ThermodynamicState | sta_a (from PartialTwoPortInterface) | if allowFlowReversal then Medium.setState_phX(port_a.p, noEvent(actualStream(port_a.h_outflow)), noEvent(actualStream(port_a.Xi_outflow))) else Medium.setState_phX(port_a.p, noEvent(inStream(port_a.h_outflow)), noEvent(inStream(port_a.Xi_outflow))) | Medium properties in port_a |
| Medium.ThermodynamicState | sta_b (from PartialTwoPortInterface) | if allowFlowReversal then Medium.setState_phX(port_b.p, noEvent(actualStream(port_b.h_outflow)), noEvent(actualStream(port_b.Xi_outflow))) else Medium.setState_phX(port_b.p, noEvent(port_b.h_outflow), noEvent(port_b.Xi_outflow)) | Medium properties in port_b |
| Fluid.HeatExchangers.ConstantEffectiveness | hex (from PartialStation) | ||
| BuildingSystems.Technologies.DistrictHeatingNetworks.Utilities.Tanh | tanhAmbience | ||
| Modelica.Blocks.Sources.Constant | constAmbience | ||
| BuildingSystems.Fluid.Movers.FlowControlled_m_flow | pumpDHN | ||
| BuildingSystems.Controls.Continuous.LimPID | conPID | ||
| BuildingSystems.Technologies.DistrictHeatingNetworks.Utilities.Tanh | tanhZone | ||
| BuildingSystems.Fluid.Sensors.Temperature | senTemSupply | ||
| BuildingSystems.Fluid.Movers.FlowControlled_m_flow | pumpHeating | ||
| BuildingSystems.Fluid.Storage.ExpansionVessel | exp | ||
| Modelica.Blocks.Sources.RealExpression | m_flow_signal | ||
| BaseClasses.ExternalIdealHeater | externalIdealHeater | ||
| Modelica.Blocks.Sources.RealExpression | Q | ||
| Modelica.Blocks.Sources.RealExpression | Tmin | ||
| Buildings.BaseClasses.RelationRadiationConvection | relationRadiationConvection | ||
| Fluid.MixingVolumes.MixingVolume | vol |