Buildings.Fluid.Geothermal.ZonedBorefields.Validation.FEFLOW

Package with models for comparative model validation with FEFLOW

Information

This package contains validation models that compare the results of the Modelica model with the ones from a finite element model that was simulated with the FEFLOW software.

In all models of this package, the temperatures TOut are the leaving water temperatures from FEFLOW, computed with FEFLOW's analytical solution for the borehole heat transfer. Comparing TOut with the temperatures TBorFieOut shows good agreement except at the initial transient at the start of the simulation when the mass flow rate changes from zero to the design flow rate. The leaving water temperatures at this initial transient show similar discrepancies as the comparison of FEFLOW's analytical and numerical solutions that is presented in the FEFLOW white paper (DHI-WASY 2010). In the FEFLOW white paper, it is explained that the reason for this difference is due to the FEFLOW's analytical solution not being valid for such short-time dynamics. Therefore, the validation of the Modelica implementation is satisfactory.

References

DHI-WASY Software FEFLOW. Finite Element Subsurface Flow & Transport Simulation System. White Paper Vol. V. DHI-WASY GmbH. Berlin 2010.

Extends from Modelica.Icons.ExamplesPackage (Icon for packages containing runnable examples).

Package Content

Name	Description
InletTemperaturePulse	Comparative model validation with FEFLOW for a response to a pulse in inlet temperature
MassFlowRatePulse100	Comparative model validation with FEFLOW for a pulse response
MassFlowRatePulse50	Comparative model validation with FEFLOW for a response to a pulse in inlet mass flow rate
MassFlowRateStep100	Comparative model validation with FEFLOW for a step response

Buildings.Fluid.Geothermal.ZonedBorefields.Validation.FEFLOW.InletTemperaturePulse

Comparative model validation with FEFLOW for a response to a pulse in inlet temperature

Buildings.Fluid.Geothermal.ZonedBorefields.Validation.FEFLOW.InletTemperaturePulse

Information

This validation cases compares the outlet temperature of a borefield with two zones against the temperatures that were calculated with the FEFLOW software. The inlet temperature in both zones is a pulse function.

Extends from Buildings.Fluid.Geothermal.ZonedBorefields.Validation.FEFLOW.MassFlowRatePulse100 (Comparative model validation with FEFLOW for a pulse response).

Parameters

Type	Name	Default	Description
Temperature	T_start	286.65	Initial temperature of the soil [K]
Bentonite	filDat		Borehole filling data
SandStone	soiDat		Soil data
Template	borFieDat		Borefield data
Template	conDat		Construction data

Modelica definition

model InletTemperaturePulse "Comparative model validation with FEFLOW for a response to a pulse in inlet temperature" extends Buildings.Fluid.Geothermal.ZonedBorefields.Validation.FEFLOW.MassFlowRatePulse100( redeclare Modelica.Blocks.Sources.Constant m_flow( k=borFieDat.conDat.mZon_flow_nominal), redeclare Modelica.Blocks.Sources.Pulse TIn( each amplitude( each final unit="K")=13, each period=3600*24*10, each offset( each final unit="K", each displayUnit="degC") =280.15), TOut( fileName=Modelica.Utilities.Files.loadResource("modelica://Buildings/Resources/Data/Fluid/Geothermal/ZonedBorefields/Validation/FEFLOW/InletTemperaturePulse.txt"))); end InletTemperaturePulse;

Buildings.Fluid.Geothermal.ZonedBorefields.Validation.FEFLOW.MassFlowRatePulse100

Comparative model validation with FEFLOW for a pulse response

Buildings.Fluid.Geothermal.ZonedBorefields.Validation.FEFLOW.MassFlowRatePulse100

Information

This validation cases compares the outlet temperature of a borefield with two zones against the temperatures that were calculated with the FEFLOW software. The mass flow rate in both zones is a pulse function.

Extends from Modelica.Icons.Example (Icon for runnable examples).

Parameters

Type	Name	Default	Description
Temperature	T_start	286.65	Initial temperature of the soil [K]
Bentonite	filDat	filDat(kFil=1.0)	Borehole filling data
SandStone	soiDat	soiDat(kSoi=1.1, cSoi=1.4E6/...	Soil data
Template	borFieDat	borFieDat(filDat=filDat, soi...	Borefield data
Template	conDat	conDat(borCon=Buildings.Flui...	Construction data
Constant	TIn[nZon]	TIn(each k(each final unit="...	Inlet temperature into each zone
Pulse	m_flow[nZon]	m_flow(amplitude=borFieDat.c...	Mass flow rate into each zone

Modelica definition

model MassFlowRatePulse100 "Comparative model validation with FEFLOW for a pulse response" extends Modelica.Icons.Example; package Medium = Buildings.Media.Water; parameter Modelica.Units.SI.Temperature T_start=286.65 "Initial temperature of the soil"; parameter ZonedBorefields.Data.Filling.Bentonite filDat( kFil=1.0) "Borehole filling data"; parameter ZonedBorefields.Data.Soil.SandStone soiDat( kSoi=1.1, cSoi=1.4E6/1800, dSoi=1800) "Soil data"; parameter Buildings.Fluid.Geothermal.ZonedBorefields.Data.Borefield.Template borFieDat( filDat=filDat, soiDat=soiDat, conDat=conDat) "Borefield data"; parameter Data.Configuration.Template conDat( borCon=Buildings.Fluid.Geothermal.Borefields.Types.BoreholeConfiguration.DoubleUTubeParallel, mBor_flow_nominal=20*995.586/24/3600*{1, 1}, each dp_nominal=85*4*100*{1, 1}, hBor=85, rBor=0.075, dBor=0.5, nZon=2, iZon={1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 2,2,2,2}, cooBor={{3, 1.5}, {6, 1.5}, {9, 1.5}, {12, 1.5}, {1.5, 4.5}, {4.5, 4.5}, {7.5, 4.5}, {10.5, 4.5}, {3, 7.5}, {6, 7.5}, {9, 7.5}, {12, 7.5}, {1.5, 10.5}, {4.5, 10.5}, {7.5, 10.5}, {10.5, 10.5}, {3, 13.5}, {6, 13.5}, {9, 13.5}, {12, 13.5}, {1.5, 16.5}, {4.5, 16.5}, {7.5, 16.5}, {10.5, 16.5}, {5.4, 22.5}, {10.8, 22.5}, {2.7, 28.5}, {8.1, 28.5}}, rTub=0.016, kTub=0.42, eTub=0.0029, xC=(2*((0.04/2)^2))^(1/2)) "Construction data"; final parameter Integer nZon(min=1) = borFieDat.conDat.nZon "Total number of independent bore field zones"; replaceable Modelica.Blocks.Sources.Constant TIn[nZon]( each k(each final unit="K", each displayUnit="degC")=293.15) constrainedby Modelica.Blocks.Interfaces.SO "Inlet temperature into each zone"; Modelica.Blocks.Sources.CombiTimeTable TOut( tableOnFile=true, tableName="tab1", columns={2,3}, smoothness=Modelica.Blocks.Types.Smoothness.LinearSegments, fileName=Modelica.Utilities.Files.loadResource("modelica://Buildings/Resources/Data/Fluid/Geothermal/ZonedBorefields/Validation/FEFLOW/Pulse.txt"), y(each unit="K", each displayUnit="degC")) "Reference results for the borehole fluid outlet temperature in each zone from FEFLOW"; Modelica.Units.SI.TemperatureDifference dTOut[2] = {if m_flow[i].y > 1E-5 then TOut.y[i] - TBorFieOut[i].T else 0 for i in 1:2} "Temperature difference FEFLOW minus Modelica outlet temperature"; Real dQNor_flow[2] = {if m_flow[i].y > 1E-5 then (TOut.y[i] - sou[i].T) / (TBorFieOut[i].T - sou[i].T)-1 else 0 for i in 1:2} "Difference in heat extraction FEFLOW divided by Modelica"; Buildings.Fluid.Geothermal.ZonedBorefields.TwoUTubes borFie( redeclare package Medium = Medium, allowFlowReversal=false, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial, TExt0_start=T_start, borFieDat=borFieDat, dT_dz=0) "Borefield"; Sensors.TemperatureTwoPort TBorFieIn[nZon]( redeclare each package Medium = Medium, each allowFlowReversal=false, each T_start=T_start, m_flow_nominal=borFieDat.conDat.mZon_flow_nominal, each tau=0) "Inlet temperature of the borefield"; Sensors.TemperatureTwoPort TBorFieOut[nZon]( redeclare each package Medium = Medium, each allowFlowReversal=false, each T_start=T_start, m_flow_nominal=borFieDat.conDat.mZon_flow_nominal, each tau=0) "Outlet temperature of the borefield"; Sources.Boundary_ph sin[nZon]( redeclare each package Medium = Medium, each nPorts=1) "Sink"; replaceable Modelica.Blocks.Sources.Pulse m_flow[nZon]( amplitude=borFieDat.conDat.mZon_flow_nominal, each width=50, each period=3600*24*10, each startTime=0) constrainedby Modelica.Blocks.Interfaces.SO "Mass flow rate into each zone"; Sources.MassFlowSource_T sou[nZon]( redeclare each package Medium = Medium, each use_m_flow_in=true, each use_T_in=true, each nPorts=1) "Mass flow source"; equation connect(TBorFieIn.port_b,borFie. port_a); connect(borFie.port_b, TBorFieOut.port_a); connect(sin[:].ports[1],TBorFieOut[:]. port_b); connect(sou.ports[1], TBorFieIn.port_a); connect(m_flow.y, sou.m_flow_in); connect(TIn.y, sou.T_in); end MassFlowRatePulse100;

Buildings.Fluid.Geothermal.ZonedBorefields.Validation.FEFLOW.MassFlowRatePulse50

Comparative model validation with FEFLOW for a response to a pulse in inlet mass flow rate

Buildings.Fluid.Geothermal.ZonedBorefields.Validation.FEFLOW.MassFlowRatePulse50

Information

Extends from Buildings.Fluid.Geothermal.ZonedBorefields.Validation.FEFLOW.MassFlowRatePulse100 (Comparative model validation with FEFLOW for a pulse response).

Parameters

Type	Name	Default	Description
Temperature	T_start	286.65	Initial temperature of the soil [K]
Bentonite	filDat		Borehole filling data
SandStone	soiDat		Soil data
Template	borFieDat		Borefield data
Template	conDat		Construction data
Constant	TIn[nZon]	redeclare Modelica.Blocks.So...	Inlet temperature into each zone

Modelica definition

model MassFlowRatePulse50 "Comparative model validation with FEFLOW for a response to a pulse in inlet mass flow rate" extends Buildings.Fluid.Geothermal.ZonedBorefields.Validation.FEFLOW.MassFlowRatePulse100( redeclare Modelica.Blocks.Sources.Pulse m_flow( amplitude=0.5*borFieDat.conDat.mZon_flow_nominal, each period=3600*24*10, offset=0.5*borFieDat.conDat.mZon_flow_nominal, each startTime=0), TOut( fileName=Modelica.Utilities.Files.loadResource("modelica://Buildings/Resources/Data/Fluid/Geothermal/ZonedBorefields/Validation/FEFLOW/MassFlowRatePulse.txt"))); end MassFlowRatePulse50;

Buildings.Fluid.Geothermal.ZonedBorefields.Validation.FEFLOW.MassFlowRateStep100

Comparative model validation with FEFLOW for a step response

Buildings.Fluid.Geothermal.ZonedBorefields.Validation.FEFLOW.MassFlowRateStep100

Information

Extends from Buildings.Fluid.Geothermal.ZonedBorefields.Validation.FEFLOW.MassFlowRatePulse100 (Comparative model validation with FEFLOW for a pulse response).

Parameters

Type	Name	Default	Description
Temperature	T_start	286.65	Initial temperature of the soil [K]
Bentonite	filDat		Borehole filling data
SandStone	soiDat		Soil data
Template	borFieDat		Borefield data
Template	conDat		Construction data
Constant	TIn[nZon]	redeclare Modelica.Blocks.So...	Inlet temperature into each zone

Modelica definition

model MassFlowRateStep100 "Comparative model validation with FEFLOW for a step response" extends Buildings.Fluid.Geothermal.ZonedBorefields.Validation.FEFLOW.MassFlowRatePulse100( redeclare Modelica.Blocks.Sources.Step m_flow( height=borFieDat.conDat.mZon_flow_nominal, each offset=0, each startTime=0), TOut( fileName=Modelica.Utilities.Files.loadResource("modelica://Buildings/Resources/Data/Fluid/Geothermal/ZonedBorefields/Validation/FEFLOW/Step.txt"))); end MassFlowRateStep100;