modelSingleSpeedPLR
Extends from Modelica.Icons.Example (Icon for runnable examples).
Information
This model validates the model Buildings.Fluid.DXSystems.Cooling.AirSource.SingleSpeed.
The difference in results of TOut and XOut at the beginning and end of the simulation is because the mass flow rate is zero. For zero mass flow rate, EnergyPlus assumes steady state condition, whereas the Modelica model is a dynamic model and hence the properties at the outlet are equal to the state variables of the model.
The EnergyPlus results were generated using the example file DXCoilSystemAuto.idf
from EnergyPlus 7.1.
The EnergyPlus results were generated using the example file
DXCoilSystemAuto.idf from EnergyPlus 7.1.
On the summer design day, the PLR is below 1.
A similar effect has been achieved in this example by turning on the coil only for the period
during which it run in EnergyPlus.
This results in on-off cycle and fluctuating results.
To compare the results, the Modelica outputs are averaged over 3600 seconds,
and the EnergyPlus outputs are used with a zero order delay to avoid the time shift in results.
Note that EnergyPlus mass fractions (X) are in mass of water vapor per mass of dry air,
whereas Modelica uses the total mass as a reference. Hence, the EnergyPlus values
are corrected by dividing them by
1+X.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Units.SI.Power | Q_flow_nominal | datCoi.sta[1].nomVal.Q_flow_nominal | Nominal power |
| Modelica.Units.SI.MassFlowRate | m_flow_nominal | datCoi.sta[1].nomVal.m_flow_nominal | Nominal mass flow rate |
| Modelica.Units.SI.PressureDifference | dp_nominal | 1141 | Pressure drop at m_flow_nominal |
| Buildings.Fluid.DXSystems.Cooling.AirSource.Data.Generic.DXCoil | datCoi | Coil data |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Buildings.Fluid.Sources.Boundary_pT | sin | Sink | |
| Buildings.Fluid.Sources.Boundary_pT | sou | Source | |
| Buildings.Fluid.DXSystems.Cooling.AirSource.SingleSpeed | sinSpeDX | Single speed DX coil | |
| Modelica.Blocks.Routing.Multiplex2 | mux | Converts in an array | |
| Buildings.Utilities.IO.BCVTB.From_degC | TCIn_K | Converts degC to K | |
| Buildings.Utilities.IO.BCVTB.From_degC | TEvaIn_K | Converts degC to K | |
| Modelica.Blocks.Math.Mean | TOutMea | Average out value over one hour | |
| Buildings.Utilities.IO.BCVTB.To_degC | TOutDegC | Convert to degree Celsius | |
| Modelica.Blocks.Sources.RealExpression | TOut | Measured outlet air temperature | |
| Modelica.Blocks.Math.Mean | XEvaOutMea | Average out value over one hour | |
| Modelica.Blocks.Sources.RealExpression | XEvaOut | Measured outlet air humidity ratio (total air) | |
| Modelica.Blocks.Math.Mean | Q_flowMea | Mean of cooling rate | |
| Modelica.Blocks.Math.Mean | Q_flowSenMea | Mean of sensible cooling rate | |
| Modelica.Blocks.Math.Mean | PMea | Mean of power | |
| Modelica.Blocks.Math.Add | add | Convert humidity ratio (dry air) to humidity ratio (total air) | |
| Modelica.Blocks.Sources.Constant | XEvaInMoiAir | Moist air fraction = 1 | |
| Modelica.Blocks.Math.Division | shrEPlu | EnergyPlus result: SHR | |
| Modelica.Blocks.Sources.Pulse | p | Pressure | |
| Modelica.Blocks.Sources.RealExpression | XEvaInMod | Modified XEvaIn | |
| Modelica.Blocks.Sources.RealExpression | XEvaOutEPluMod | Modified XEvaOut of energyPlus to comapre with the model results | |
| Modelica.Blocks.Sources.BooleanTable | onOff | EnergyPlus PLR converted into on-off signal for this model | |
| Modelica.Blocks.Sources.TimeTable | TCIn | Condenser inlet temperature | |
| Modelica.Blocks.Sources.TimeTable | TEvaIn | Coil inlet temperature | |
| Modelica.Blocks.Sources.TimeTable | XEvaIn | Water fraction of moist air | |
| Modelica.Blocks.Sources.TimeTable | TOutEPlu_ori | EnergyPlus result: outlet temperature | |
| Modelica.Blocks.Sources.TimeTable | PEPlu_ori | EnergyPlus result: electric power | |
| Modelica.Blocks.Sources.TimeTable | XEvaOutEPlu_ori | EnergyPlus result: outlet water mass fraction | |
| Modelica.Blocks.Sources.TimeTable | Q_flowSenEPlu_ori | EnergyPlus result: sensible heat flow | |
| Modelica.Blocks.Sources.TimeTable | Q_flowEPlu_ori | EnergyPlus result: heat flow | |
| Modelica.Blocks.Math.Add | QCoo_flow | Total cooling heat flow rate | |
| UnitDelay | PEPlu | Delay input signal by one hour to match timestep with Modelica simulation | |
| UnitDelay | Q_flowSenEPlu | Delay input signal by one hour to match timestep with Modelica simulation | |
| UnitDelay | Q_flowEPlu | Delay input signal by one hour to match timestep with Modelica simulation | |
| UnitDelay | TOutEPlu | Delay input signal by one hour to match timestep with Modelica simulation | |
| UnitDelay | XEvaOutEPlu | Delay input signal by one hour to match timestep with Modelica simulation | |
| Modelica.Blocks.Math.MultiSum | multiSum | Add small value to measured value to avoid division by zero | |
| Modelica.Blocks.Sources.Constant | small | Small value to avoid division by zero |
Contents
| Name | Description |
|---|---|
 Medium | Medium model |
 UnitDelayprotected |
Revisions
-
April 5, 2023, by Karthik Devaprasad and Xing Lu:
Updated class name to differentiate from validation models for heating coils.
Updated connect statements to reflect change in input instance onsinSpeDXfromTConIntoTOut.
Updated comments and formatting for readability. -
January 22, 2016, by Michael Wetter:
Corrected type declaration of pressure difference. This is for #404. -
September 24, 2015 by Michael Wetter:
ImplementedUnitDelayto avoid a translation warning becauseUnitDelay.firstTriggerdoes not set thefixedattribute in MSL 3.2.1. -
June 9, 2015, by Michael Wetter:
Corrected wrong link to run script. -
December 22, 2014 by Michael Wetter:
RemovedModelica.Fluid.Systemto address issue #311. -
September 4, 2012 by Michael Wetter:
Modified example to avoid having to access protected data. -
August 20, 2012 by Kaustubh Phalak:
First implementation.