modelPartialBorefield

Borefield model using single U-tube borehole heat exchanger configuration.Calculates the average fluid temperature T_fts of the borefield for a given (time dependent) load Q_flow

Extends from BuildingSystems.Fluid.Interfaces.PartialTwoPortInterface, BuildingSystems.Fluid.Interfaces.TwoPortFlowResistanceParameters.

Information

This model simulates a borefield containing one or multiple boreholes using the parameters in the borFieDat record.

Heat transfer to the soil is modeled using only one borehole heat exchanger (To be added in an extended model). The fluid mass flow rate into the 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 thermal interaction between the borehole wall and the surrounding soil is modeled using BuildingSystems.Fluid.Geothermal.Borefields.BaseClasses.HeatTransfer.GroundTemperatureResponse, which uses a cell-shifting load aggregation technique to calculate the borehole wall temperature after calculating and/or read (from a previous calculation) the borefield's thermal response factor.

Parameters

Type	Name	Default	Description
Real	mSenFac	1	Factor for scaling the sensible thermal mass of the volume
Modelica.Units.SI.Time	tLoaAgg	300	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
BuildingSystems.Fluid.Geothermal.Borefields.Data.Borefield.Template	borFieDat		Borefield data
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
Advanced › g-function
Boolean	forceGFunCalc	false	Set to true to force the thermal response to be calculated at the start instead of checking whether this has been pre-computed
Integer	nSegGFun	12	Number of segments to use in the calculation of the g-function
Integer	nClu	5	Number of borehole clusters to use in the calculation of the g-function
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
Dynamics
Boolean	dynFil	true	Set to false to remove the dynamics of the filling material.

Components

Type	Name	Description
Modelica.Blocks.Interfaces.RealOutput	TBorAve	Average borehole wall temperature in the borefield
BuildingSystems.Fluid.Geothermal.Borefields.BaseClasses.HeatTransfer.GroundTemperatureResponse	groTemRes	Ground temperature response
BuildingSystems.Fluid.Geothermal.Borefields.BaseClasses.Boreholes.BaseClasses.PartialBorehole	borHol

Name	Description
Medium	Medium in the component

Revisions

April 9, 2021, by Michael Wetter:
Corrected placement of each keyword.
See Buildings, PR #2440.
August 25, 2020, by Filip Jorissen:
Switched port connections for masFloDiv. See #41.
March 24, 2020, by Damien Picard:
Propagated flowReversal into masFloDiv and masFloMul.
June 7, 2019, by Massimo Cimmino:
Converted instances that are not of interest to user to be protected.
June 4, 2019, by Massimo Cimmino:
Added an output for the average borehole wall temperature. See #1107.
April 11, 2019, by Filip Jorissen:
Added choicesAllMatching for borFieDat. See #1117.
January 18, 2019, by Jianjun Hu:
Limited the media choice to water and glycolWater. See #1050.
July 2018, by Alex Laferrière:
Changed into a partial model and changed documentation to reflect the new approach used by the borefield models.
July 2014, by Damien Picard:
First implementation.

modelPartialBorefield

Information

Parameters

Components

Contents

Revisions