modelExternalIdealHeater
Extends from BuildingSystems.Fluid.Interfaces.PartialTwoPortInterface (Partial model with two ports and declaration of quantities that are used by many models).
Information
The model recieves an input signal Q_in which is the heat flow rate that has to be extracted from the fluid. Before the heat flow rate is extracted, the input signal passes through a limiter block with an upper and lower limit.
The upper limit ensures that the return temperature does not drops down to a value under a minimum temperature TDHNMin defined from outside.
The lower limit is in general set to 0 in order to avoid the block to cool the fluid.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Real | eps_inst | 1 | Factor accountig per inneficiency of installation. Increase heat to be delivered |
| 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 | |
| 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.Thermal.HeatTransfer.Interfaces.HeatPort_a | Q_flowHea | ||
| Modelica.Blocks.Interfaces.RealInput | Q_in | ||
| BuildingSystems.Interfaces.Temp_KInput | TDHNMin |
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 |
| Modelica.Thermal.HeatTransfer.Sources.PrescribedHeatFlow | prescribedHeatFlow | ||
| Modelica.Thermal.HeatTransfer.Sources.PrescribedHeatFlow | prescribedHeatFlow1 | ||
| Modelica.Blocks.Math.Gain | gain | ||
| Modelica.Blocks.Math.Feedback | feedback | ||
| Modelica.Blocks.Math.Product | product | ||
| Modelica.Blocks.Math.Gain | Q_flowMax | ||
| BuildingSystems.Fluid.MixingVolumes.MixingVolume | vol | ||
| BuildingSystems.Fluid.Sensors.TemperatureTwoPort | senTem | ||
| BuildingSystems.Fluid.Sensors.MassFlowRate | senMasFlo | ||
| Modelica.Blocks.Nonlinear.VariableLimiter | variableLimiter | ||
| Modelica.Blocks.Sources.Constant | const | ||
| Modelica.Blocks.Math.Max | max | ||
| Modelica.Blocks.Math.Gain | gain1 |