modelSingleSpeed
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,
with a nominal cooling capacity of 10500 Watts instead of using
autosizing. This allowed to have a part load ratio of one.
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.Sources.TimeTable | plr_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.Math.RealToBoolean | onOff | Enable the DX coil when input is greater than 0.5 | |
| 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 from model | |
| 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.Sources.TimeTable | TOutEPlu | EnergyPlus result: outlet temperature | |
| Modelica.Blocks.Sources.TimeTable | Q_flowEPlu | EnergyPlus result: heat flow | |
| Modelica.Blocks.Sources.TimeTable | Q_flowSenEPlu | EnergyPlus result: sensible heat flow | |
| Modelica.Blocks.Math.Division | shrEPlu | EnergyPlus result: SHR | |
| Modelica.Blocks.Sources.TimeTable | XEvaOutEPlu | EnergyPlus result: outlet water mass fraction | |
| Modelica.Blocks.Sources.TimeTable | PEPlu | EnergyPlus result: electric power | |
| 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.Math.Add | QCoo_flow | Total cooling heat flow rate |
Contents
| Name | Description |
|---|---|
 Medium | Medium model |
Revisions
-
April 5, 2023, by Karthik Devaprasad and Xing Lu:
Updated model name to differentiate from heating coil validation models.
Updated connection statements to reflect change in input instance onsinSpeDXfromTConIntoTOut.
Updated formatting for readability. -
January 22, 2016, by Michael Wetter:
Corrected type declaration of pressure difference. This is for #404. -
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.