modelPartialStorage
Extends from Buildings.Fluid.Geothermal.ZonedBorefields.Interfaces.PartialTwoNPortsInterface, Buildings.Fluid.Geothermal.ZonedBorefields.Interfaces.TwoNPortsFlowResistanceParameters.
Information
This model simulates a borehole thermal energy storage system with multiple
zones of boreholes. Boreholes within the same zone are connected
in parallel. The borefield configuration and thermal parameters are defined in
the borFieDat record.
Heat transfer to the soil is modeled using one borehole heat exchanger (To be added in an extended model) per borefield zone. The fluid mass flow rate into each borehole is divided to reflect the per-borehole fluid mass flow rate. The borehole model calculates the dynamics within the borehole itself using an axial discretization and a resistance-capacitance network for the internal thermal resistances between the individual pipes and between each pipe and the borehole wall.
The ground thermal response at each borehole segment is evaluated using analytical thermal response factors. Spatial and temporal superposition are used to evaluate the total temperature change at each of the borehole segments.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Units.SI.Time | tLoaAgg | 3600.0 | Time resolution of load aggregation |
| Integer | nCel | 5 | Number of cells per aggregation level |
| Integer | nSeg | 10 | Number of segments to use in vertical discretization of the boreholes |
| Buildings.Fluid.Geothermal.ZonedBorefields.Data.Borefield.Template | borFieDat | Borefield data record | |
| Integer | nZon | borFieDat.conDat.nZon | Total number of independent bore field zones |
| Integer | nBorPerZon | borFieDat.conDat.nBorPerZon | Number of boreholes per borefield zone |
| Dynamics › Conservation equations | |||
| Modelica.Fluid.Types.Dynamics | energyDynamics | Modelica.Fluid.Types.Dynamics.DynamicFreeInitial | Type of energy balance: dynamic (3 initialization options) or steady state |
| Initialization | |||
| Medium.AbsolutePressure | p_start | Medium.p_default | Start value of pressure |
| Modelica.Units.SI.Temperature[nSeg] | TFlu_start | TGro_start | Start value of fluid temperature |
| Initialization › Soil | |||
| Modelica.Units.SI.Temperature | TExt0_start | 283.15 | Initial far field temperature |
| Modelica.Units.SI.Temperature[nSeg] | TExt_start | {if z[i] >= z0 then TExt0_start + (z[i] - z0)*dT_dz else TExt0_start for i in 1:nSeg} | Temperature of the undisturbed ground |
| Initialization › Filling material | |||
| Modelica.Units.SI.Temperature[nSeg] | TGro_start | TExt_start | Start value of grout temperature |
| Initialization › Temperature profile | |||
| Modelica.Units.SI.Height | z0 | 10 | Depth below which the temperature gradient starts |
| Real | dT_dz | 0.01 | Vertical temperature gradient of the undisturbed soil for h below z0 |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Buildings.Fluid.Geothermal.Borefields.BaseClasses.Boreholes.BaseClasses.PartialBorehole[nZon] | borHol | ||
| Buildings.Fluid.Geothermal.ZonedBorefields.BaseClasses.HeatTransfer.GroundTemperatureResponse | groTemRes | Ground thermal response | |
| Modelica.Blocks.Interfaces.RealOutput[nZon] | TBorAve | Average borehole wall temperature in the borefield | |
| Modelica.Blocks.Interfaces.RealOutput[nZon] | QBorAve | Average (per borehole) heat transfer rate in each zone |
Contents
| Name | Description |
|---|---|
| Medium | Medium in the borehole pipes |
Revisions
-
February 2024, by Massimo Cimmino:
First implementation.