modelBoreholeSegment
Extends from Buildings.Fluid.Interfaces.PartialFourPortInterface, Buildings.Fluid.Interfaces.TwoPortFlowResistanceParameters, Buildings.Fluid.Interfaces.LumpedVolumeDeclarations.
Information
Horizontal layer that is used to model a U-tube borehole heat exchanger. This model combines three models, each simulating a different aspect of a borehole heat exchanger.
The instance pipFil computes the heat transfer in the pipes and the filling material.
This computation is done using the model
Buildings.Fluid.Geothermal.Boreholes.BaseClasses.HexInternalElement.
The instance soi computes transient and steady state heat transfer in the soil using a vertical cylinder.
The computation is done using the model
Buildings.HeatTransfer.Conduction.SingleLayerCylinder.
The model TBouCon computes the far-field temperature boundary condition,
i.e., the temperature at the outer
surface of the above cylindrical heat transfer computation.
The computation is done using the model
Buildings.Fluid.Geothermal.Boreholes.BaseClasses.SingleUTubeBoundaryCondition.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Boolean | homotopyInitialization | true | = true, use homotopy method |
| Modelica.Units.SI.Radius | rBor | 0.1 | Radius of the borehole |
| Modelica.Units.SI.Height | hSeg | Height of the element | |
| Modelica.Units.SI.Length | xC | 0.05 | Shank spacing, defined as the distance between the center of a pipe and the center of the borehole |
| Soil | |||
| Buildings.HeatTransfer.Data.Soil.Generic | matSoi | Thermal properties of soil | |
| Modelica.Units.SI.Radius | rExt | 3 | Radius of the soil used for the external boundary condition |
| Modelica.Units.SI.Temperature | TExt_start | 283.15 | Initial far field temperature |
| Integer | nSta | 10 | Number of state variables in the soil |
| Modelica.Units.SI.Time | samplePeriod | 604800 | Sample period for the external boundary condition |
| Filling material | |||
| Buildings.HeatTransfer.Data.BoreholeFillings.Generic | matFil | Thermal properties of the filling material | |
| Modelica.Units.SI.Temperature | TFil_start | 283.15 | Initial temperature of the filling material |
| Nominal condition | |||
| Modelica.Units.SI.MassFlowRate | m_flow_nominal | Nominal mass flow rate | |
| Advanced | |||
| Modelica.Units.SI.MassFlowRate | m_flow_small | 1E-4*abs(m_flow_nominal) | Small mass flow rate for regularization of zero flow |
| Tubes | |||
| Modelica.Units.SI.Radius | rTub | 0.02 | Radius of the tubes |
| Modelica.Units.SI.ThermalConductivity | kTub | 0.5 | Thermal conductivity of the tubes |
| Modelica.Units.SI.Length | eTub | 0.002 | Thickness of the tubes |
| Assumptions | |||
| Boolean | allowFlowReversal | true | = true to allow flow reversal, false restricts to design direction (port_a -> port_b) |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Buildings.Fluid.Geothermal.Boreholes.BaseClasses.HexInternalElement | pipFil | Internal part of the borehole including the pipes and the filling material | |
| Buildings.HeatTransfer.Conduction.SingleLayerCylinder | soi | Heat conduction in the soil | |
| Buildings.Fluid.Geothermal.Boreholes.BaseClasses.SingleUTubeBoundaryCondition | TBouCon | Thermal boundary condition for the far-field |
Contents
| Name | Description |
|---|---|
| Medium | Medium in the component |
Revisions
-
April 14, 2020, by Michael Wetter:
ChangedhomotopyInitializationto a constant.
This is for IBPSA, #1341. -
February 14, 2014, by Michael Wetter:
Removed unused parametersB0andB1. Updated hyperlinks in the documentation. -
October 8, 2013, by Michael Wetter:
Removed parametershow_V_flow. -
July 28 2011, by Pierre Vigouroux:
First implementation.