modelSpaceCooling
Space cooling system
Extends from Modelica.Icons.Example.
Information
This block is identical to Buildings.Examples.Tutorial.SpaceCooling.System3, except that an air filter is added to the cooling system.
The major input signals for the air filter are configured as follows:
- The input trace substance C_inflow.y changes from 10 µg/m³ (7.73e-9 kg/kg, assuming an air density of 1.293 kg/m³) to 15 µg/m³ (1.16e-8 kg/kg) at 12:00 (15552000+12*3600 seconds).
-
The filter replacement signal
repSigis false.
The expected output are:
- The filtration efficiency airFil.eps[1] decreases along with the contaminant airFil.masAcc.mCon build up.
- The fan power fan.P slightly increases, caused by the rising pressure drop across the filter as contaminants build up.
Note that these changes in filtration efficiency and pressure drop are relatively minor over the span of a single day, with more pronounced effects expected over months.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Units.SI.Volume | V | 6*10*3 | Room volume |
| Real | eps | 0.8 | Heat recovery effectiveness |
| Modelica.Units.SI.Temperature | TASup_nominal | 291.15 | Nominal air temperature supplied to room |
| Modelica.Units.SI.DimensionlessRatio | wASup_nominal | 0.012 | Nominal air humidity ratio supplied to room [kg/kg] assuming 90% relative humidity |
| Modelica.Units.SI.Temperature | TRooSet | 297.15 | Nominal room air temperature |
| Modelica.Units.SI.Temperature | TOut_nominal | 303.15 | Design outlet air temperature |
| Modelica.Units.SI.Temperature | THeaRecLvg | TOut_nominal - eps*(TOut_nominal - TRooSet) | Air temperature leaving the heat recovery |
| Modelica.Units.SI.DimensionlessRatio | wHeaRecLvg | 0.0135 | Air humidity ratio leaving the heat recovery [kg/kg] |
| Modelica.Units.SI.HeatFlowRate | QRooInt_flow | 1000 | Internal heat gains of the room |
| Modelica.Units.SI.HeatFlowRate | QRooC_flow_nominal | -QRooInt_flow - 10E3/30*(TOut_nominal - TRooSet) | Nominal cooling load of the room |
| Modelica.Units.SI.MassFlowRate | mA_flow_nominal | 1.3*QRooC_flow_nominal/1006/(TASup_nominal - TRooSet) | Nominal air mass flow rate, increased by factor 1.3 to allow for recovery after temperature setback |
| Modelica.Units.SI.TemperatureDifference | dTFan | 2 | Estimated temperature raise across fan that needs to be made up by the cooling coil |
| Modelica.Units.SI.HeatFlowRate | QCoiC_flow_nominal | mA_flow_nominal*(TASup_nominal - THeaRecLvg - dTFan)*1006 + mA_flow_nominal*(wASup_nominal - wHeaRecLvg)*2458.3e3 | Cooling load of coil, taking into account outside air sensible and latent heat removal |
| Modelica.Units.SI.Temperature | TWSup_nominal | 285.15 | Water supply temperature |
| Modelica.Units.SI.Temperature | TWRet_nominal | 289.15 | Water return temperature |
| Modelica.Units.SI.MassFlowRate | mW_flow_nominal | -QCoiC_flow_nominal/(TWRet_nominal - TWSup_nominal)/4200 | Nominal water mass flow rate |
| Buildings.Fluid.AirFilters.Data.Generic | per | Performance dataset of the air filter |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Buildings.Fluid.MixingVolumes.MixingVolume | vol | ||
| Modelica.Thermal.HeatTransfer.Components.ThermalConductor | theCon | Thermal conductance with the ambient | |
| Modelica.Thermal.HeatTransfer.Sources.PrescribedTemperature | TOut | Outside temperature | |
| Modelica.Thermal.HeatTransfer.Sources.FixedHeatFlow | preHea | Prescribed heat flow | |
| Buildings.Fluid.Movers.FlowControlled_m_flow | fan | Supply air fan | |
| Buildings.Fluid.HeatExchangers.ConstantEffectiveness | hex | Heat recovery | |
| Buildings.Fluid.HeatExchangers.WetCoilEffectivenessNTU | cooCoi | Cooling coil | |
| Buildings.Fluid.Sources.Outside | out | ||
| Buildings.Fluid.Sources.MassFlowSource_T | souWat | Source for water flow rate | |
| Buildings.Fluid.Sources.Boundary_pT | sinWat | Sink for water circuit | |
| BoundaryConditions.WeatherData.ReaderTMY3 | weaDat | Weather data reader | |
| BoundaryConditions.WeatherData.Bus | weaBus | ||
| Buildings.Controls.OBC.CDL.Reals.Sources.Constant | mAir_flow | Fan air flow rate | |
| Buildings.Fluid.Sensors.TemperatureTwoPort | senTemHXOut | Temperature sensor for heat recovery outlet on supply side | |
| Buildings.Fluid.Sensors.TemperatureTwoPort | senTemSupAir | Temperature sensor for supply air | |
| Buildings.Controls.OBC.CDL.Reals.Sources.Constant | TRooSetPoi | Room temperature set point | |
| Modelica.Thermal.HeatTransfer.Sensors.TemperatureSensor | senTemRoo | Room temperature sensor | |
| Buildings.Controls.Continuous.LimPID | conRoo | Room controller | |
| Buildings.Fluid.AirFilters.Empirical | airFil | Air filter | |
| Modelica.Blocks.Sources.Ramp | C_inflow | Contaminant mass flow rate fraction | |
| Buildings.Fluid.Sensors.TraceSubstancesTwoPort | C_out | Trace substance sensor of outlet air | |
| Buildings.Controls.OBC.CDL.Logical.Sources.Constant | repSig | Filter replacement signal | |
| Buildings.Controls.OBC.CDL.Reals.Subtract | subDif | Substance difference between inlet and outlet |
Contents
| Name | Description |
|---|---|
| MediumA | Medium for air |
| MediumW | Medium for water |
Revisions
-
June 30, 2024, by Sen Huang:
First implementation based on Buildings.Examples.Tutorial.SpaceCooling.System3.