modelElectricChillersDirectETS
Example model for district cooling system with
an electric chiller plant and a direct controlled ETS at each building
Extends from Modelica.Icons.Example (Icon for runnable examples).
Information
This model illustrates an example of district cooling system, consisting of a cooling plant with parallel electric chillers ( Buildings.DHC.Plants.Cooling.ElectricChillerParallel), a two-pipe distribution network with plug flow pipes ( Buildings.DHC.Networks.Distribution2PipePlugFlow_v), and time series building load that have directly connected ETS with the chilled water return temperatures controlled above a minimum threshold ( Buildings.DHC.Loads.Cooling.BuildingTimeSeriesWithETS). This configuration is illustrated in the schematic below.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Units.SI.Pressure | dpDis | 30000 | Total pressure drop in the district pipes |
| Modelica.Units.SI.MassFlowRate[nLoa] | mCon_flow_nominal | fill(10, nLoa) | Nominal mass flow rate in each connection line |
| Modelica.Units.SI.HeatFlowRate[nLoa] | QCoo_flow_nominal | {Buildings.DHC.Loads.BaseClasses.getPeakLoad(string = "#Peak space cooling load", filNam = filNam[i]) for i in 1:nLoa} | Space cooling design load (<=0) |
| Modelica.Units.SI.MassFlowRate[nLoa] | mBui_flow_nominal | {-QCoo_flow_nominal[i]/(cp*buiETS[i].dT_nominal) for i in 1:nLoa} | Nominal mass flow rate of building cooling side |
| Chiller and cooling tower | |||
| Buildings.Fluid.Chillers.Data.ElectricEIR.ElectricEIRChiller_York_YT_1055kW_5_96COP_Vanes | perChi | Performance data of chiller | |
| Modelica.Units.SI.MassFlowRate | mCHW_flow_nominal | 18.3 | Nominal chilled water mass flow rate |
| Modelica.Units.SI.MassFlowRate | mCW_flow_nominal | 34.7 | Nominal condenser water mass flow rate |
| Modelica.Units.SI.PressureDifference | dpCHW_nominal | 44.8*1000 | Nominal chilled water side pressure |
| Modelica.Units.SI.PressureDifference | dpCW_nominal | 46.2*1000 | Nominal condenser water side pressure |
| Modelica.Units.SI.Power | QChi_nominal | mCHW_flow_nominal*4200*(6.67 - 18.56) | Nominal cooling capaciaty (Negative means cooling) |
| Pumps | |||
| Buildings.Fluid.Movers.Data.Generic | perCHWPum | Performance data for chilled water pumps | |
| Buildings.Fluid.Movers.Data.Generic | perCWPum | Performance data for condenser water pumps | |
| Network | |||
| Integer | nLoa | 3 | Number of served loads |
| Buildings | |||
| String[nLoa] | filNam | {Modelica.Utilities.Files.loadResource("modelica://Buildings/Resources/Data/DHC/Loads/Examples/MediumOffice-90.1-2010-5A.mos"), Modelica.Utilities.Files.loadResource("modelica://Buildings/Resources/Data/DHC/Loads/Examples/MediumOffice-90.1-2010-5A.mos"), Modelica.Utilities.Files.loadResource("modelica://Buildings/Resources/Data/DHC/Loads/Examples/MediumOffice-90.1-2010-5A.mos")} | Library path of the file with thermal loads as time series |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Buildings.DHC.Plants.Cooling.ElectricChillerParallel | pla | District cooling plant | |
| Buildings.BoundaryConditions.WeatherData.ReaderTMY3 | weaDat | Weather data | |
| Modelica.Blocks.Sources.Constant | TCHWSupSet | Chilled water supply temperature setpoint | |
| Buildings.DHC.Networks.Distribution2PipePlugFlow_v | dis | Distribution network for district cooling system | |
| Buildings.DHC.Loads.Cooling.BuildingTimeSeriesWithETS[nLoa] | buiETS | Vectorized time series building load model connected with ETS for cooling | |
| Modelica.Blocks.Sources.Constant | TDisRetSet | Setpoint for district return temperature | |
| Modelica.Blocks.Math.Sum | QTotCoo_flow | Total cooling flow rate for all buildings | |
| Buildings.Controls.OBC.CDL.Reals.LessThreshold | offCoo | Threshold comparison to disable the plant | |
| Modelica.Blocks.Math.Gain | norQFlo | Normalized Q_flow | |
| HeatTransfer.Sources.FixedTemperature[nLoa] | gnd | Ground | |
| Controls.OBC.CDL.Logical.Timer | tim | ||
| Controls.OBC.CDL.Logical.Not | onPla | On signal for the plant | |
| HeatTransfer.Sources.FixedTemperature[nLoa + 1] | gnd1 | Ground |
Contents
| Name | Description |
|---|---|
 Medium | Medium model for water |
Revisions
-
August 22, 2023, by Michael Wetter:
Changed call toloadResources. This is needed for Dymola 2024x beta1 on Linux. -
January 2, 2023, by Kathryn Hinkelman:
Revised chilled water pump controls to be constant speed and running 1-and-1 with the chillers.
Changed building-side ets from direct uncontrolled to controlled.
Revised distribution network from fixed resistance pipes to plug flow pipes. -
December 21, 2022, by Kathryn Hinkelman:
CorrecteddpMealocation to be at the terminal building. Removed in-building pumping for direct uncontrolled ETS example.
This is for #2912. -
December 18, 2022, by Kathryn Hinkelman:
Relocated dp sensor for CHW pump control to most distal building. This is for #2912. - March 20, 2022, by Chengnan Shi:
First implementation.