modelThermostaticValve
Extends from AixLib.Obsolete.BaseClasses.ObsoleteModel (Icon for classes that are obsolete and will be removed in later versions), AixLib.Fluid.Interfaces.PartialTwoPortTransport (Partial element transporting fluid between two ports without storage of mass or energy).
Information
Overview
Model for a simple thermostatic valve.
Concept
Development of SimpleValve by incorporating the behaviour of a thermostatic head as a P controller with a maximum deviation of P and an influence of the pressure drop on the sensed temperature.
It is possible to not close the valve completely by allowing for some minimal leakage. Use this option carefully and always check the influence it might have on your results.
Example Results
AixLib.HVAC.Radiators.Examples.PumpRadiatorThermostaticValve
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Real | leakageOpening | 0.0001 | may be useful for simulation stability. Always check the influence it has on your results |
| Assumptions | |||
| Boolean | allowFlowReversal (from PartialTwoPort) | true | = false to simplify equations, assuming, but not enforcing, no flow reversal |
| Advanced | |||
| Modelica.Units.SI.PressureDifference | dp_start (from PartialTwoPortTransport) | 0 | Guess value of dp = port_a.p - port_b.p |
| Medium.MassFlowRate | m_flow_start (from PartialTwoPortTransport) | 0 | Guess value of m_flow = port_a.m_flow |
| Medium.MassFlowRate | m_flow_small (from PartialTwoPortTransport) | Small mass flow rate for regularization of zero flow | |
| Advanced › Diagnostics | |||
| Boolean | show_T (from PartialTwoPortTransport) | true | = true, if temperatures at port_a and port_b are computed |
| Boolean | show_V_flow (from PartialTwoPortTransport) | true | = true, if volume flow rate at inflowing port is computed |
| Valve | |||
| Real | Kvs | 1.4 | Kv value at full opening (=1) |
| Thermostatic head | |||
| Real | Kv_setT | 0.8 | Kv value when set temperature = measured temperature |
| Real | P | 2 | Deviation of P-controller when valve is closed |
| Real | Influence_PressureDrop | 0.14 | influence of the pressure drop in K |
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 | T_room | temperature in room | |
| Modelica.Blocks.Interfaces.RealInput | T_setRoom | set temperature in room |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Medium.MassFlowRate | m_flow (from PartialTwoPortTransport) | Mass flow rate in design flow direction | |
| Modelica.Units.SI.PressureDifference | dp (from PartialTwoPortTransport) | Pressure difference between port_a and port_b (= port_a.p - port_b.p) | |
| Modelica.Units.SI.VolumeFlowRate | V_flow (from PartialTwoPortTransport) | m_flow/Modelica.Fluid.Utilities.regStep(m_flow, Medium.density(Medium.setState_phX(p = port_a.p, h = inStream(port_a.h_outflow), X = inStream(port_a.Xi_outflow))), Medium.density(Medium.setState_phX(p = port_b.p, h = inStream(port_b.h_outflow), X = inStream(port_b.Xi_outflow))), m_flow_small) | Volume flow rate at inflowing port (positive when flow from port_a to port_b) |
| Medium.Temperature | port_a_T (from PartialTwoPortTransport) | Modelica.Fluid.Utilities.regStep(port_a.m_flow, Medium.temperature(Medium.setState_phX(p = port_a.p, h = inStream(port_a.h_outflow), X = inStream(port_a.Xi_outflow))), Medium.temperature(Medium.setState_phX(port_a.p, port_a.h_outflow, port_a.Xi_outflow)), m_flow_small) | Temperature close to port_a, if show_T = true |
| Medium.Temperature | port_b_T (from PartialTwoPortTransport) | Modelica.Fluid.Utilities.regStep(port_b.m_flow, Medium.temperature(Medium.setState_phX(p = port_b.p, h = inStream(port_b.h_outflow), X = inStream(port_b.Xi_outflow))), Medium.temperature(Medium.setState_phX(port_b.p, port_b.h_outflow, port_b.Xi_outflow)), m_flow_small) | Temperature close to port_b, if show_T = true |
| Real | opening | valve opening | |
| Real | TempDiff | Difference between measured temperature and set temperature | |
| Real | Influence_PressureDrop_inK | Influence of pressure drop in Kelvin. |
Revisions
-
November 2014 by Marcus Fuchs:
Changed model to use Annex 60 base class -
November 13, 2013 by Ana Constantin:
Implemented