Buildings.Fluid.Geothermal.Borefields.BaseClasses.Boreholes.BaseClasses.Functions.Validation
Models to validate borehole thermal resistances functions
Information
This package contains validation models for the classes in Buildings.Fluid.Geothermal.Borefields.BaseClasses.Boreholes.BaseClasses.Functions.
Extends from Modelica.Icons.ExamplesPackage (Icon for packages containing runnable examples).
Package Content
| Name | Description |
|---|---|
 ConvectionResistanceCircularPipe
|
Validation of the correlation used to evaluate the convection resistance in circular pipes |
| InternalResistancesOneUTube
|
Validation of the thermal resistances using the method of Bauer et al. (2011) for a single U-tube borehole |
| InternalResistancesOneUTubeNegative
|
Validation of the thermal resistances using the method of Bauer et al. (2011) for a single U-tube borehole |
| InternalResistancesTwoUTube
|
Validation of the thermal resistances using the method of Bauer et al. (2011) for a double U-tube borehole |
| InternalResistancesTwoUTubeNegative
|
Validation of the thermal resistances using the method of Bauer et al. (2011) for a double U-tube borehole |
| MultipoleThermalResistances_OneUTube
|
Validation of the thermal resitances for a single U-tube borehole |
| MultipoleThermalResistances_TwoUTube
|
Validation of the thermal resitances for a double U-tube borehole |
Buildings.Fluid.Geothermal.Borefields.BaseClasses.Boreholes.BaseClasses.Functions.Validation.ConvectionResistanceCircularPipe
Validation of the correlation used to evaluate the convection resistance in circular pipes
Information
This example validates the implementation of Buildings.Fluid.Geothermal.Borefields.BaseClasses.Boreholes.BaseClasses.Functions.convectionResistanceCircularPipe for the evaluation of the convection thermal resistance in circular pipes.
In this validation case, the fluid mass flow rate increases with time so that Re = t.
Extends from Modelica.Icons.Example (Icon for runnable examples).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Height | hSeg | 1.0 | Height of the element [m] |
| Radius | rTub | 0.02 | Tube radius [m] |
| Length | eTub | 0.002 | Tube thickness [m] |
| ThermalConductivity | kMed | 0.6 | Thermal conductivity of the fluid [W/(m.K)] |
| DynamicViscosity | muMed | 1.002e-3 | Dynamic viscosity of the fluid [Pa.s] |
| SpecificHeatCapacity | cpMed | 4182 | Specific heat capacity of the fluid [J/(kg.K)] |
| MassFlowRate | m_flow_nominal | 1 | Nominal mass flow rate [kg/s] |
Modelica definition
model ConvectionResistanceCircularPipe
"Validation of the correlation used to evaluate the convection resistance in circular pipes"
extends Modelica.Icons.Example;
parameter Modelica.Units.SI.Height hSeg=1.0 "Height of the element";
parameter Modelica.Units.SI.Radius rTub=0.02 "Tube radius";
parameter Modelica.Units.SI.Length eTub=0.002 "Tube thickness";
// thermal properties
parameter Modelica.Units.SI.ThermalConductivity kMed=0.6
"Thermal conductivity of the fluid";
parameter Modelica.Units.SI.DynamicViscosity muMed=1.002e-3
"Dynamic viscosity of the fluid";
parameter Modelica.Units.SI.SpecificHeatCapacity cpMed=4182
"Specific heat capacity of the fluid";
parameter Modelica.Units.SI.MassFlowRate m_flow_nominal=1
"Nominal mass flow rate";
Real Re "Reynolds number";
Real Nu "Reynolds number";
Modelica.Units.SI.MassFlowRate m_flow "Mass flow rate";
Modelica.Units.SI.ThermalResistance RConv "Convection resistance";
equation
Re = time;
Re = 2*m_flow/(muMed*Modelica.Constants.pi*(rTub-eTub));
RConv = Buildings.Fluid.Geothermal.Borefields.BaseClasses.Boreholes.BaseClasses.Functions.convectionResistanceCircularPipe(
hSeg=hSeg,
rTub=rTub,
eTub=eTub,
kMed=kMed,
muMed=muMed,
cpMed=cpMed,
m_flow=m_flow,
m_flow_nominal=m_flow_nominal);
Nu = 1/(kMed*Modelica.Constants.pi*hSeg*RConv);
end ConvectionResistanceCircularPipe;
Buildings.Fluid.Geothermal.Borefields.BaseClasses.Boreholes.BaseClasses.Functions.Validation.InternalResistancesOneUTube
Validation of the thermal resistances using the method of Bauer et al. (2011) for a single U-tube borehole
Information
This example validates the implementation of Buildings.Fluid.Geothermal.Borefields.BaseClasses.Boreholes.BaseClasses.Functions.internalResistancesOneUTube for the evaluation of the internal thermal resistances of a single U-tube borehole.
Extends from Modelica.Icons.Example (Icon for runnable examples).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Real | Rb | 0.0 | Borehole thermal resistance (Not used) [(m.K)/W] |
| Height | hSeg | 1.0 | Height of the element [m] |
| Radius | rBor | 0.07 | Radius of the borehole [m] |
| Radius | rTub | 0.02 | Radius of the tube [m] |
| Length | eTub | 0.002 | Thickness of the tubes [m] |
| Length | sha | 0.03 | Shank spacing, defined as the distance between the center of a pipe and the center of the borehole [m] |
| ThermalConductivity | kFil | 1.5 | Thermal conductivity of the grout [W/(m.K)] |
| ThermalConductivity | kSoi | 2.5 | Thermal conductivity of the soi [W/(m.K)] |
| ThermalConductivity | kTub | 0.4 | Thermal conductivity of the tube [W/(m.K)] |
| ThermalConductivity | kMed | 0.6 | Thermal conductivity of the fluid [W/(m.K)] |
| DynamicViscosity | muMed | 1.0e-3 | Dynamic viscosity of the fluid [Pa.s] |
| SpecificHeatCapacity | cpMed | 4180.0 | Specific heat capacity of the fluid [J/(kg.K)] |
| MassFlowRate | m_flow_nominal | 0.25 | Nominal mass flow rate [kg/s] |
| Real | x | Capacity location | |
| ThermalResistance | Rgb | Thermal resistance between grout zone and borehole wall [K/W] | |
| ThermalResistance | Rgg | Thermal resistance between the two grout zones [K/W] | |
| ThermalResistance | RCondGro | Thermal resistance between: pipe wall to capacity in grout [K/W] |
Modelica definition
model InternalResistancesOneUTube
"Validation of the thermal resistances using the method of Bauer et al. (2011) for a single U-tube borehole"
extends Modelica.Icons.Example;
// Geometry of the borehole
parameter Real Rb(unit="(m.K)/W") = 0.0
"Borehole thermal resistance (Not used)";
parameter Modelica.Units.SI.Height hSeg=1.0 "Height of the element";
parameter Modelica.Units.SI.Radius rBor=0.07 "Radius of the borehole";
// Geometry of the pipe
parameter Modelica.Units.SI.Radius rTub=0.02 "Radius of the tube";
parameter Modelica.Units.SI.Length eTub=0.002 "Thickness of the tubes";
parameter Modelica.Units.SI.Length sha=0.03
"Shank spacing, defined as the distance between the center of a pipe and the center of the borehole";
// Thermal properties (Solids)
parameter Modelica.Units.SI.ThermalConductivity kFil=1.5
"Thermal conductivity of the grout";
parameter Modelica.Units.SI.ThermalConductivity kSoi=2.5
"Thermal conductivity of the soi";
parameter Modelica.Units.SI.ThermalConductivity kTub=0.4
"Thermal conductivity of the tube";
// Thermal properties (Fluid)
parameter Modelica.Units.SI.ThermalConductivity kMed=0.6
"Thermal conductivity of the fluid";
parameter Modelica.Units.SI.DynamicViscosity muMed=1.0e-3
"Dynamic viscosity of the fluid";
parameter Modelica.Units.SI.SpecificHeatCapacity cpMed=4180.0
"Specific heat capacity of the fluid";
parameter Modelica.Units.SI.MassFlowRate m_flow_nominal=0.25
"Nominal mass flow rate";
// Outputs
parameter Real x(fixed=false) "Capacity location";
parameter Modelica.Units.SI.ThermalResistance Rgb(fixed=false)
"Thermal resistance between grout zone and borehole wall";
parameter Modelica.Units.SI.ThermalResistance Rgg(fixed=false)
"Thermal resistance between the two grout zones";
parameter Modelica.Units.SI.ThermalResistance RCondGro(fixed=false)
"Thermal resistance between: pipe wall to capacity in grout";
initial equation
(x, Rgb, Rgg, RCondGro) =
Buildings.Fluid.Geothermal.Borefields.BaseClasses.Boreholes.BaseClasses.Functions.internalResistancesOneUTube(
hSeg=hSeg,
rBor=rBor,
rTub=rTub,
eTub=eTub,
sha=sha,
kFil=kFil,
kSoi=kSoi,
kTub=kTub,
Rb=Rb,
kMed=kMed,
muMed=muMed,
cpMed=cpMed,
m_flow_nominal=m_flow_nominal);
end InternalResistancesOneUTube;
Buildings.Fluid.Geothermal.Borefields.BaseClasses.Boreholes.BaseClasses.Functions.Validation.InternalResistancesOneUTubeNegative
Validation of the thermal resistances using the method of Bauer et al. (2011) for a single U-tube borehole
Information
This example validates the implementation of Buildings.Fluid.Geothermal.Borefields.BaseClasses.Boreholes.BaseClasses.Functions.internalResistancesOneUTube for the evaluation of the internal thermal resistances of a single U-tube borehole.
In this case, the shank spacing is defined such that the pipes are close to the
borehole wall, rendering the short-circuit thermal resistances negative. The
capacity location x is then automatically set to zero.
Extends from Modelica.Icons.Example (Icon for runnable examples).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Real | Rb | 0.0 | Borehole thermal resistance (Not used) [(m.K)/W] |
| Height | hSeg | 1.0 | Height of the element [m] |
| Radius | rBor | 0.07 | Radius of the borehole [m] |
| Radius | rTub | 0.02 | Radius of the tube [m] |
| Length | eTub | 0.002 | Thickness of the tubes [m] |
| Length | sha | 0.05 | Shank spacing, defined as the distance between the center of a pipe and the center of the borehole [m] |
| ThermalConductivity | kFil | 1.5 | Thermal conductivity of the grout [W/(m.K)] |
| ThermalConductivity | kSoi | 2.5 | Thermal conductivity of the soi [W/(m.K)] |
| ThermalConductivity | kTub | 0.4 | Thermal conductivity of the tube [W/(m.K)] |
| ThermalConductivity | kMed | 0.6 | Thermal conductivity of the fluid [W/(m.K)] |
| DynamicViscosity | muMed | 1.0e-3 | Dynamic viscosity of the fluid [Pa.s] |
| SpecificHeatCapacity | cpMed | 4180.0 | Specific heat capacity of the fluid [J/(kg.K)] |
| MassFlowRate | m_flow_nominal | 0.25 | Nominal mass flow rate [kg/s] |
| Real | x | Capacity location | |
| ThermalResistance | Rgb | Thermal resistance between grout zone and borehole wall [K/W] | |
| ThermalResistance | Rgg | Thermal resistance between the two grout zones [K/W] | |
| ThermalResistance | RCondGro | Thermal resistance between: pipe wall to capacity in grout [K/W] |
Modelica definition
model InternalResistancesOneUTubeNegative
"Validation of the thermal resistances using the method of Bauer et al. (2011) for a single U-tube borehole"
extends Modelica.Icons.Example;
// Geometry of the borehole
parameter Real Rb(unit="(m.K)/W") = 0.0
"Borehole thermal resistance (Not used)";
parameter Modelica.Units.SI.Height hSeg=1.0 "Height of the element";
parameter Modelica.Units.SI.Radius rBor=0.07 "Radius of the borehole";
// Geometry of the pipe
parameter Modelica.Units.SI.Radius rTub=0.02 "Radius of the tube";
parameter Modelica.Units.SI.Length eTub=0.002 "Thickness of the tubes";
parameter Modelica.Units.SI.Length sha=0.05
"Shank spacing, defined as the distance between the center of a pipe and the center of the borehole";
// Thermal properties (Solids)
parameter Modelica.Units.SI.ThermalConductivity kFil=1.5
"Thermal conductivity of the grout";
parameter Modelica.Units.SI.ThermalConductivity kSoi=2.5
"Thermal conductivity of the soi";
parameter Modelica.Units.SI.ThermalConductivity kTub=0.4
"Thermal conductivity of the tube";
// Thermal properties (Fluid)
parameter Modelica.Units.SI.ThermalConductivity kMed=0.6
"Thermal conductivity of the fluid";
parameter Modelica.Units.SI.DynamicViscosity muMed=1.0e-3
"Dynamic viscosity of the fluid";
parameter Modelica.Units.SI.SpecificHeatCapacity cpMed=4180.0
"Specific heat capacity of the fluid";
parameter Modelica.Units.SI.MassFlowRate m_flow_nominal=0.25
"Nominal mass flow rate";
// Outputs
parameter Real x(fixed=false) "Capacity location";
parameter Modelica.Units.SI.ThermalResistance Rgb(fixed=false)
"Thermal resistance between grout zone and borehole wall";
parameter Modelica.Units.SI.ThermalResistance Rgg(fixed=false)
"Thermal resistance between the two grout zones";
parameter Modelica.Units.SI.ThermalResistance RCondGro(fixed=false)
"Thermal resistance between: pipe wall to capacity in grout";
initial equation
(x, Rgb, Rgg, RCondGro) =
Buildings.Fluid.Geothermal.Borefields.BaseClasses.Boreholes.BaseClasses.Functions.internalResistancesOneUTube(
hSeg=hSeg,
rBor=rBor,
rTub=rTub,
eTub=eTub,
sha=sha,
kFil=kFil,
kSoi=kSoi,
kTub=kTub,
Rb=Rb,
kMed=kMed,
muMed=muMed,
cpMed=cpMed,
m_flow_nominal=m_flow_nominal);
end InternalResistancesOneUTubeNegative;
Buildings.Fluid.Geothermal.Borefields.BaseClasses.Boreholes.BaseClasses.Functions.Validation.InternalResistancesTwoUTube
Validation of the thermal resistances using the method of Bauer et al. (2011) for a double U-tube borehole
Information
This example validates the implementation of Buildings.Fluid.Geothermal.Borefields.BaseClasses.Boreholes.BaseClasses.Functions.internalResistancesTwoUTube for the evaluation of the internal thermal resistances of a double U-tube borehole.
Extends from Modelica.Icons.Example (Icon for runnable examples).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Real | Rb | 0.0 | Borehole thermal resistance (Not used) [(m.K)/W] |
| Height | hSeg | 1.0 | Height of the element [m] |
| Radius | rBor | 0.07 | Radius of the borehole [m] |
| Radius | rTub | 0.02 | Radius of the tube [m] |
| Length | eTub | 0.002 | Thickness of the tubes [m] |
| Length | sha | 0.025 | Shank spacing, defined as the distance between the center of a pipe and the center of the borehole [m] |
| ThermalConductivity | kFil | 0.5 | Thermal conductivity of the grout [W/(m.K)] |
| ThermalConductivity | kSoi | 2.5 | Thermal conductivity of the soi [W/(m.K)] |
| ThermalConductivity | kTub | 0.4 | Thermal conductivity of the tube [W/(m.K)] |
| ThermalConductivity | kMed | 0.6 | Thermal conductivity of the fluid [W/(m.K)] |
| DynamicViscosity | muMed | 1.0e-3 | Dynamic viscosity of the fluid [Pa.s] |
| SpecificHeatCapacity | cpMed | 4180.0 | Specific heat capacity of the fluid [J/(kg.K)] |
| MassFlowRate | m_flow_nominal | 0.25 | Nominal mass flow rate [kg/s] |
| Real | x | Capacity location | |
| ThermalResistance | Rgb | Thermal resistance between grout zone and borehole wall [K/W] | |
| ThermalResistance | Rgg1 | Thermal resistance between the two adjacent grout zones [K/W] | |
| ThermalResistance | Rgg2 | Thermal resistance between the two opposite grout zones [K/W] | |
| ThermalResistance | RCondGro | Thermal resistance between: pipe wall to capacity in grout [K/W] |
Modelica definition
model InternalResistancesTwoUTube
"Validation of the thermal resistances using the method of Bauer et al. (2011) for a double U-tube borehole"
extends Modelica.Icons.Example;
// Geometry of the borehole
parameter Real Rb(unit="(m.K)/W") = 0.0
"Borehole thermal resistance (Not used)";
parameter Modelica.Units.SI.Height hSeg=1.0 "Height of the element";
parameter Modelica.Units.SI.Radius rBor=0.07 "Radius of the borehole";
// Geometry of the pipe
parameter Modelica.Units.SI.Radius rTub=0.02 "Radius of the tube";
parameter Modelica.Units.SI.Length eTub=0.002 "Thickness of the tubes";
parameter Modelica.Units.SI.Length sha=0.025
"Shank spacing, defined as the distance between the center of a pipe and the center of the borehole";
// Thermal properties (Solids)
parameter Modelica.Units.SI.ThermalConductivity kFil=0.5
"Thermal conductivity of the grout";
parameter Modelica.Units.SI.ThermalConductivity kSoi=2.5
"Thermal conductivity of the soi";
parameter Modelica.Units.SI.ThermalConductivity kTub=0.4
"Thermal conductivity of the tube";
// Thermal properties (Fluid)
parameter Modelica.Units.SI.ThermalConductivity kMed=0.6
"Thermal conductivity of the fluid";
parameter Modelica.Units.SI.DynamicViscosity muMed=1.0e-3
"Dynamic viscosity of the fluid";
parameter Modelica.Units.SI.SpecificHeatCapacity cpMed=4180.0
"Specific heat capacity of the fluid";
parameter Modelica.Units.SI.MassFlowRate m_flow_nominal=0.25
"Nominal mass flow rate";
// Outputs
parameter Real x(fixed=false) "Capacity location";
parameter Modelica.Units.SI.ThermalResistance Rgb(fixed=false)
"Thermal resistance between grout zone and borehole wall";
parameter Modelica.Units.SI.ThermalResistance Rgg1(fixed=false)
"Thermal resistance between the two adjacent grout zones";
parameter Modelica.Units.SI.ThermalResistance Rgg2(fixed=false)
"Thermal resistance between the two opposite grout zones";
parameter Modelica.Units.SI.ThermalResistance RCondGro(fixed=false)
"Thermal resistance between: pipe wall to capacity in grout";
initial equation
(x, Rgb, Rgg1, Rgg2, RCondGro) =
Buildings.Fluid.Geothermal.Borefields.BaseClasses.Boreholes.BaseClasses.Functions.internalResistancesTwoUTube(
hSeg=hSeg,
rBor=rBor,
rTub=rTub,
eTub=eTub,
sha=sha,
kFil=kFil,
kSoi=kSoi,
kTub=kTub,
Rb=Rb,
kMed=kMed,
muMed=muMed,
cpMed=cpMed,
m_flow_nominal=m_flow_nominal);
end InternalResistancesTwoUTube;
Buildings.Fluid.Geothermal.Borefields.BaseClasses.Boreholes.BaseClasses.Functions.Validation.InternalResistancesTwoUTubeNegative
Validation of the thermal resistances using the method of Bauer et al. (2011) for a double U-tube borehole
Information
This example validates the implementation of Buildings.Fluid.Geothermal.Borefields.BaseClasses.Boreholes.BaseClasses.Functions.internalResistancesTwoUTube for the evaluation of the internal thermal resistances of a double U-tube borehole.
In this case, the shank spacing is defined such that the pipes are close to the
borehole wall, rendering the short-circuit thermal resistances negative. The
capacity location x is then automatically set to zero.
Extends from Modelica.Icons.Example (Icon for runnable examples).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Real | Rb | 0.0 | Borehole thermal resistance (Not used) [(m.K)/W] |
| Height | hSeg | 1.0 | Height of the element [m] |
| Radius | rBor | 0.07 | Radius of the borehole [m] |
| Radius | rTub | 0.02 | Radius of the tube [m] |
| Length | eTub | 0.002 | Thickness of the tubes [m] |
| Length | sha | 0.05 | Shank spacing, defined as the distance between the center of a pipe and the center of the borehole [m] |
| ThermalConductivity | kFil | 1.5 | Thermal conductivity of the grout [W/(m.K)] |
| ThermalConductivity | kSoi | 2.5 | Thermal conductivity of the soi [W/(m.K)] |
| ThermalConductivity | kTub | 0.4 | Thermal conductivity of the tube [W/(m.K)] |
| ThermalConductivity | kMed | 0.6 | Thermal conductivity of the fluid [W/(m.K)] |
| DynamicViscosity | muMed | 1.0e-3 | Dynamic viscosity of the fluid [Pa.s] |
| SpecificHeatCapacity | cpMed | 4180.0 | Specific heat capacity of the fluid [J/(kg.K)] |
| MassFlowRate | m_flow_nominal | 0.25 | Nominal mass flow rate [kg/s] |
| Real | x | Capacity location | |
| ThermalResistance | Rgb | Thermal resistance between grout zone and borehole wall [K/W] | |
| ThermalResistance | Rgg1 | Thermal resistance between the two adjacent grout zones [K/W] | |
| ThermalResistance | Rgg2 | Thermal resistance between the two opposite grout zones [K/W] | |
| ThermalResistance | RCondGro | Thermal resistance between: pipe wall to capacity in grout [K/W] |
Modelica definition
model InternalResistancesTwoUTubeNegative
"Validation of the thermal resistances using the method of Bauer et al. (2011) for a double U-tube borehole"
extends Modelica.Icons.Example;
// Geometry of the borehole
parameter Real Rb(unit="(m.K)/W") = 0.0
"Borehole thermal resistance (Not used)";
parameter Modelica.Units.SI.Height hSeg=1.0 "Height of the element";
parameter Modelica.Units.SI.Radius rBor=0.07 "Radius of the borehole";
// Geometry of the pipe
parameter Modelica.Units.SI.Radius rTub=0.02 "Radius of the tube";
parameter Modelica.Units.SI.Length eTub=0.002 "Thickness of the tubes";
parameter Modelica.Units.SI.Length sha=0.05
"Shank spacing, defined as the distance between the center of a pipe and the center of the borehole";
// Thermal properties (Solids)
parameter Modelica.Units.SI.ThermalConductivity kFil=1.5
"Thermal conductivity of the grout";
parameter Modelica.Units.SI.ThermalConductivity kSoi=2.5
"Thermal conductivity of the soi";
parameter Modelica.Units.SI.ThermalConductivity kTub=0.4
"Thermal conductivity of the tube";
// Thermal properties (Fluid)
parameter Modelica.Units.SI.ThermalConductivity kMed=0.6
"Thermal conductivity of the fluid";
parameter Modelica.Units.SI.DynamicViscosity muMed=1.0e-3
"Dynamic viscosity of the fluid";
parameter Modelica.Units.SI.SpecificHeatCapacity cpMed=4180.0
"Specific heat capacity of the fluid";
parameter Modelica.Units.SI.MassFlowRate m_flow_nominal=0.25
"Nominal mass flow rate";
// Outputs
parameter Real x(fixed=false) "Capacity location";
parameter Modelica.Units.SI.ThermalResistance Rgb(fixed=false)
"Thermal resistance between grout zone and borehole wall";
parameter Modelica.Units.SI.ThermalResistance Rgg1(fixed=false)
"Thermal resistance between the two adjacent grout zones";
parameter Modelica.Units.SI.ThermalResistance Rgg2(fixed=false)
"Thermal resistance between the two opposite grout zones";
parameter Modelica.Units.SI.ThermalResistance RCondGro(fixed=false)
"Thermal resistance between: pipe wall to capacity in grout";
initial equation
(x, Rgb, Rgg1, Rgg2, RCondGro) =
Buildings.Fluid.Geothermal.Borefields.BaseClasses.Boreholes.BaseClasses.Functions.internalResistancesTwoUTube(
hSeg=hSeg,
rBor=rBor,
rTub=rTub,
eTub=eTub,
sha=sha,
kFil=kFil,
kSoi=kSoi,
kTub=kTub,
Rb=Rb,
kMed=kMed,
muMed=muMed,
cpMed=cpMed,
m_flow_nominal=m_flow_nominal);
end InternalResistancesTwoUTubeNegative;
Buildings.Fluid.Geothermal.Borefields.BaseClasses.Boreholes.BaseClasses.Functions.Validation.MultipoleThermalResistances_OneUTube
Validation of the thermal resitances for a single U-tube borehole
Information
This example validates the implementation of Buildings.Fluid.Geothermal.Borefields.BaseClasses.Boreholes.BaseClasses.Functions.multipoleThermalResistances for the evaluation of the borehole thermal resistances.
The multipole method is used to evaluate thermal resistances for a single U-tube borehole with asymmetrically positionned pipes. Results are compared to reference values given in Claesson and Hellström (2011).
References
Claesson, J., & Hellström, G. (2011). Multipole method to calculate borehole thermal resistances in a borehole heat exchanger. HVAC&R Research, 17(6), 895-911.
Extends from Modelica.Icons.Example (Icon for runnable examples).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Integer | nPip | 2 | Number of pipes |
| Integer | J | 3 | Number of multipoles |
| Position | xPip[nPip] | {0.03,-0.03} | x-Coordinates of pipes [m] |
| Position | yPip[nPip] | {0.00,0.02} | y-Coordinates of pipes [m] |
| Radius | rBor | 0.07 | Borehole radius [m] |
| Radius | rPip[nPip] | fill(0.02, nPip) | Outter radius of pipes [m] |
| ThermalConductivity | kFil | 1.5 | Thermal conductivity of grouting material [W/(m.K)] |
| ThermalConductivity | kSoi | 2.5 | Thermal conductivity of soil material [W/(m.K)] |
| Real | RFluPip[nPip] | fill(1.2/(2*Modelica.Constan... | Fluid to pipe wall thermal resistances [(m.K)/W] |
| Temperature | TBor | 0 | Average borehole wall temperature [K] |
| Real | RDelta_Ref[nPip, nPip] | {{1/3.680,1/0.242},{1/0.242,... | Reference delta-circuit thermal resistances [(m.K)/W] |
| Real | R_Ref[nPip, nPip] | {{0.25592,0.01561},{0.01561,... | Reference internal thermal resistances [(m.K)/W] |
Modelica definition
model MultipoleThermalResistances_OneUTube
"Validation of the thermal resitances for a single U-tube borehole"
extends Modelica.Icons.Example;
parameter Integer nPip=2 "Number of pipes";
parameter Integer J=3 "Number of multipoles";
parameter Modelica.Units.SI.Position[nPip] xPip={0.03,-0.03}
"x-Coordinates of pipes";
parameter Modelica.Units.SI.Position[nPip] yPip={0.00,0.02}
"y-Coordinates of pipes";
parameter Modelica.Units.SI.Radius rBor=0.07 "Borehole radius";
parameter Modelica.Units.SI.Radius[nPip] rPip=fill(0.02, nPip)
"Outter radius of pipes";
parameter Modelica.Units.SI.ThermalConductivity kFil=1.5
"Thermal conductivity of grouting material";
parameter Modelica.Units.SI.ThermalConductivity kSoi=2.5
"Thermal conductivity of soil material";
parameter Real[nPip] RFluPip(each unit="(m.K)/W")=
fill(1.2/(2*Modelica.Constants.pi*kFil), nPip)
"Fluid to pipe wall thermal resistances";
parameter Modelica.Units.SI.Temperature TBor=0
"Average borehole wall temperature";
parameter Real[nPip,nPip] RDelta_Ref(each unit="(m.K)/W")=
{{1/3.680, 1/0.242},{1/0.242, 1/3.724}}
"Reference delta-circuit thermal resistances";
parameter Real[nPip,nPip] R_Ref(each unit="(m.K)/W")=
{{0.25592, 0.01561},{0.01561, 0.25311}}
"Reference internal thermal resistances";
Real[nPip,nPip] RDelta(each unit="(m.K)/W")
"Delta-circuit thermal resistances";
Real[nPip,nPip] R(each unit="(m.K)/W")
"Internal thermal resistances";
equation
(RDelta, R) = Buildings.Fluid.Geothermal.Borefields.BaseClasses.Boreholes.BaseClasses.Functions.multipoleThermalResistances(
nPip, J, xPip, yPip, rBor, rPip, kFil, kSoi, RFluPip, TBor);
end MultipoleThermalResistances_OneUTube;
Buildings.Fluid.Geothermal.Borefields.BaseClasses.Boreholes.BaseClasses.Functions.Validation.MultipoleThermalResistances_TwoUTube
Validation of the thermal resitances for a double U-tube borehole
Information
This example validates the implementation of Buildings.Fluid.Geothermal.Borefields.BaseClasses.Boreholes.BaseClasses.Functions.multipoleThermalResistances for the evaluation of the borehole thermal resistances.
The multipole method is used to evaluate thermal resistances for a double U-tube borehole with symmetrically positionned pipes. Results are compared to reference values given in Claesson (2012).
References
Claesson, J. (2012). Multipole method to calculate borehole thermal resistances. Mathematical report. Department of Building Physics, Lund University, Box 118, SE-221 00 Lund, Sweden. 128 pages.
Extends from Modelica.Icons.Example (Icon for runnable examples).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Integer | nPip | 4 | Number of pipes |
| Integer | J | 3 | Number of multipoles |
| Position | xPip[nPip] | {0.03,-0.03,-0.03,0.03} | x-Coordinates of pipes [m] |
| Position | yPip[nPip] | {0.03,0.03,-0.03,-0.03} | y-Coordinates of pipes [m] |
| Radius | rBor | 0.07 | Borehole radius [m] |
| Radius | rPip[nPip] | fill(0.02, nPip) | Outter radius of pipes [m] |
| ThermalConductivity | kFil | 1.5 | Thermal conductivity of grouting material [W/(m.K)] |
| ThermalConductivity | kSoi | 2.5 | Thermal conductivity of soil material [W/(m.K)] |
| Real | RFluPip[nPip] | fill(1.2/(2*Modelica.Constan... | Fluid to pipe wall thermal resistances [(m.K)/W] |
| Temperature | TBor | 0 | Average borehole wall temperature [K] |
| Real | RDelta_Ref[nPip, nPip] | {{1/3.61,1/0.35,-1/0.25,1/0.... | Reference delta-circuit thermal resistances [(m.K)/W] |
| Real | R_Ref[nPip, nPip] | {{0.2509,0.0192,-0.0122,0.01... | Reference internal thermal resistances [(m.K)/W] |
Modelica definition
model MultipoleThermalResistances_TwoUTube
"Validation of the thermal resitances for a double U-tube borehole"
extends Modelica.Icons.Example;
parameter Integer nPip=4 "Number of pipes";
parameter Integer J=3 "Number of multipoles";
parameter Modelica.Units.SI.Position[nPip] xPip={0.03,-0.03,-0.03,0.03}
"x-Coordinates of pipes";
parameter Modelica.Units.SI.Position[nPip] yPip={0.03,0.03,-0.03,-0.03}
"y-Coordinates of pipes";
parameter Modelica.Units.SI.Radius rBor=0.07 "Borehole radius";
parameter Modelica.Units.SI.Radius[nPip] rPip=fill(0.02, nPip)
"Outter radius of pipes";
parameter Modelica.Units.SI.ThermalConductivity kFil=1.5
"Thermal conductivity of grouting material";
parameter Modelica.Units.SI.ThermalConductivity kSoi=2.5
"Thermal conductivity of soil material";
parameter Real[nPip] RFluPip(each unit="(m.K)/W")=
fill(1.2/(2*Modelica.Constants.pi*kFil), nPip)
"Fluid to pipe wall thermal resistances";
parameter Modelica.Units.SI.Temperature TBor=0
"Average borehole wall temperature";
parameter Real[nPip,nPip] RDelta_Ref(each unit="(m.K)/W")=
{{1/3.61, 1/0.35, -1/0.25, 1/0.35},
{1/0.35, 1/3.61, 1/0.35, -1/0.25},
{-1/0.25, 1/0.35, 1/3.61, 1/0.35},
{1/0.35, -1/0.25, 1/0.35, 1/3.61}}
"Reference delta-circuit thermal resistances";
parameter Real[nPip,nPip] R_Ref(each unit="(m.K)/W")=
{{0.2509, 0.0192, -0.0122, 0.0192},
{0.0192, 0.2509, 0.0192, -0.0122},
{-0.0122, 0.0192, 0.2509, 0.0192},
{0.0192, -0.0122, 0.0192, 0.2509}}
"Reference internal thermal resistances";
Real[nPip,nPip] RDelta(each unit="(m.K)/W")
"Delta-circuit thermal resistances";
Real[nPip,nPip] R(each unit="(m.K)/W")
"Internal thermal resistances";
equation
(RDelta, R) = Buildings.Fluid.Geothermal.Borefields.BaseClasses.Boreholes.BaseClasses.Functions.multipoleThermalResistances(
nPip, J, xPip, yPip, rBor, rPip, kFil, kSoi, RFluPip, TBor);
end MultipoleThermalResistances_TwoUTube;