Buildings.Experimental.DHC.Loads.Combined

Package with models for loads

Information

This package contains models of building loads that are used to build example models of DHC systems.

Extends from Modelica.Icons.VariantsPackage (Icon for package containing variants).

Package Content

Name	Description
BuildingTimeSeriesWithETS	Model of a building with loads provided as time series, connected to an ETS
Examples	This package contains example models
BaseClasses	Package with base classes that are used by multiple models

Buildings.Experimental.DHC.Loads.Combined.BuildingTimeSeriesWithETS

Model of a building with loads provided as time series, connected to an ETS

Buildings.Experimental.DHC.Loads.Combined.BuildingTimeSeriesWithETS

Information

This model is composed of a heat pump based energy transfer station model Buildings.Experimental.DHC.EnergyTransferStations.Combined.HeatPumpHeatExchanger connected to a simplified building model where the space heating, cooling and hot water loads are provided as time series.

Scaling

The parameter bui.facMul is the multiplier factor applied to the building loads that are provided as time series. It is used to represent multiple identical buildings served by a unique energy transfer station. The parameter facMul is the multiplier factor applied to the whole system composed of the building(s) and the energy transfer station. It is used to represent multiple identical ETSs served by the DHC system. So, if for instance the overall heating and cooling efficiency is equal to 1, then the load on the district loop is the load provided as time series multiplied by facMul * bui.facMul.

Note that the parameters QCoo_flow_nominal, QHea_flow_nominal and QHot_flow_nominal are the ETS design values. They include the building loads multiplier factor bui.facMul but not the building and ETS multiplier factor facMul.

Extends from Buildings.Experimental.DHC.Loads.Combined.BaseClasses.PartialBuildingWithETS (Partial model with ETS model and partial building model).

Parameters

Type	Name	Default	Description
replaceable package MediumSer		Water	Service side medium
replaceable package MediumSerHea_a		Water	Service side medium at heating inlet
replaceable package MediumBui		Water	Building side medium
String	filNam		Library path of the file with thermal loads as time series
Configuration
Integer	nPorts_heaWat	1	Number of heating water fluid ports
Integer	nPorts_chiWat	1	Number of chilled water fluid ports
Scaling
Real	facMul	1	Multiplier factor
ETS model parameters
Temperature	TDisWatMin	6 + 273.15	District water minimum temperature [K]
Temperature	TDisWatMax	17 + 273.15	District water maximum temperature [K]
TemperatureDifference	dT_nominal	4	Water temperature drop/increase accross load and source-side HX (always positive) [K]
Temperature	TChiWatSup_nominal	18 + 273.15	Chilled water supply temperature [K]
Temperature	THeaWatSup_nominal	38 + 273.15	Heating water supply temperature [K]
Pressure	dp_nominal	50000	Pressure difference at nominal flow rate (for each flow leg) [Pa]
Real	COPHeaWat_nominal	4.0	COP of heat pump for heating water production [1]
Real	COPHotWat_nominal	2.3	COP of heat pump for hot water production [1]
Assumptions
Boolean	allowFlowReversalSer	false	Set to true to allow flow reversal on service side
Boolean	allowFlowReversalBui	false	Set to true to allow flow reversal on building side

Connectors

Type	Name	Description
FluidPort_a	port_aSerAmb	Fluid connector for ambient water service supply line
FluidPort_b	port_bSerAmb	Fluid connector for ambient water service return line
FluidPort_a	port_aSerHea	Fluid connector for heating service supply line
FluidPort_b	port_bSerHea	Fluid connector for heating service return line
FluidPort_a	port_aSerCoo	Fluid connector for cooling service supply line
FluidPort_b	port_bSerCoo	Fluid connector for cooling service return line
Bus	weaBus	Weather data bus
output RealOutput	QHea_flow	Total heating heat flow rate transferred to the loads (>=0) [W]
output RealOutput	QCoo_flow	Total cooling heat flow rate transferred to the loads (<=0) [W]
output RealOutput	PHea	Power drawn by heating system [W]
output RealOutput	PCoo	Power drawn by cooling system [W]
output RealOutput	PFan	Power drawn by fan motors [W]
output RealOutput	PPum	Power drawn by pump motors [W]
output RealOutput	QFue_flow[nFue]	Fuel energy input rate [W]
input RealInput	TChiWatSupSet	Chilled water supply temperature set point [K]
input RealInput	THeaWatSupMaxSet	Heating water supply temperature set point - Maximum value [K]
input RealInput	THeaWatSupMinSet	Heating water supply temperature set point - Minimum value [K]
output RealOutput	PPumETS	ETS pump power [W]
input RealInput	THotWatSupSet	Service hot water supply temperature set point [K]
input RealInput	TColWat	Cold water temperature [K]

Modelica definition

model BuildingTimeSeriesWithETS "Model of a building with loads provided as time series, connected to an ETS" extends Buildings.Experimental.DHC.Loads.Combined.BaseClasses.PartialBuildingWithETS ( redeclare Buildings.Experimental.DHC.Loads.BaseClasses.Examples.BaseClasses.BuildingTimeSeries bui( final filNam=filNam, have_hotWat=true, T_aHeaWat_nominal=ets.THeaWatSup_nominal, T_bHeaWat_nominal=ets.THeaWatRet_nominal, T_aChiWat_nominal=ets.TChiWatSup_nominal, T_bChiWat_nominal=ets.TChiWatRet_nominal), ets( have_hotWat=true, QChiWat_flow_nominal=QCoo_flow_nominal, QHeaWat_flow_nominal=QHea_flow_nominal, QHotWat_flow_nominal=QHot_flow_nominal)); parameter String filNam "Library path of the file with thermal loads as time series"; final parameter Modelica.Units.SI.HeatFlowRate QCoo_flow_nominal( max=-Modelica.Constants.eps)= bui.facMul * bui.QCoo_flow_nominal "Space cooling design load (<=0)"; final parameter Modelica.Units.SI.HeatFlowRate QHea_flow_nominal( min=Modelica.Constants.eps)= bui.facMul * bui.QHea_flow_nominal "Space heating design load (>=0)"; final parameter Modelica.Units.SI.HeatFlowRate QHot_flow_nominal( min=Modelica.Constants.eps)= bui.facMul * Buildings.Experimental.DHC.Loads.BaseClasses.getPeakLoad( string="#Peak water heating load", filNam=Modelica.Utilities.Files.loadResource(filNam)) "Hot water design load (>=0)"; Buildings.Controls.OBC.CDL.Interfaces.RealInput THotWatSupSet( final unit="K", displayUnit="degC") "Service hot water supply temperature set point"; Buildings.Controls.OBC.CDL.Interfaces.RealInput TColWat( final unit="K", displayUnit="degC") "Cold water temperature"; Buildings.Controls.OBC.CDL.Reals.MultiplyByParameter loaHeaNor( k=1/QHea_flow_nominal) "Normalized heating load"; Buildings.Controls.OBC.CDL.Reals.GreaterThreshold enaHeaCoo[2](each t=1e-4) "Threshold comparison to enable heating and cooling"; Modelica.Blocks.Sources.BooleanConstant enaSHW( final k=true) if have_hotWat "SHW production enable signal"; Buildings.Controls.OBC.CDL.Reals.MultiplyByParameter loaCooNor(k=1/ QCoo_flow_nominal) "Normalized cooling load"; equation connect(bui.QReqHotWat_flow, ets.loaSHW); connect(THotWatSupSet, ets.THotWatSupSet); connect(TColWat, ets.TColWat); connect(enaHeaCoo[1].y, ets.uHea); connect(enaHeaCoo[2].y, ets.uCoo); connect(enaSHW.y, ets.uSHW); connect(loaHeaNor.y, enaHeaCoo[1].u); connect(loaCooNor.y, enaHeaCoo[2].u); connect(bui.QReqHea_flow, loaHeaNor.u); connect(bui.QReqCoo_flow, loaCooNor.u); connect(loaHeaNor.y, resTHeaWatSup.u); end BuildingTimeSeriesWithETS;