modelThermalResistorVertical

Lumped thermal element transporting heat without storing it

Extends from Modelica.Thermal.HeatTransfer.Interfaces.Element1D (Partial heat transfer element with two HeatPort connectors that does not store energy).

Information

1. Purpose of model

Quasi-static vertical thermal resistor for one-dimensional heat conduction between two vertically neighbouring control volumes. The thermal resistance is computed from half the control volume height and the cross-sectional area with a constant thermal conductivity. Same idea as the Modelica Standard Library ThermalConductor, but parametrized by the thermal resistance instead of the conductance, which allows a resistance of zero (no temperature difference) in series connections. This is the variant without dispersion; for hydrodynamic dispersion use ThermalResistorVertical_withDispersion.

2. Level of detail, physical effects considered, and physical insight

L1: Quasi-static 1D heat transport in vertical direction. No thermal storage within the resistor; the temperature drop is given by the calculated thermal resistance.

3. Limits of validity

- No thermal mass inside the resistor (instantaneous conduction).

- Constant thermal conductivity (no temperature dependency, no dispersion).

- The factor 0.5 in the resistance formula assumes the temperature node sits at the centre of the control volume.

4. Interfaces

port_a: lower heat port — heat inlet (Heat, inherited from Element1D)

port_b: upper heat port — heat outlet (Heat, inherited from Element1D)

5. Nomenclature

R_v R vertical thermal resistance [K/W]
\lambda lambda thermal conductivity of the aquifer/aquitard [W/(m·K)]
A_s A cross-sectional area of control volume [m²]
z_\mathrm{cv} z height of control volume [m]
\dot{Q} Q_flow heat flow rate [W] (inherited from Element1D)
\Delta T dT temperature difference across resistor [K] (inherited from Element1D)

6. Governing Equations

Vertical thermal resistance (half-cell formulation):

R = 0.5*z / (lambda * A)

Heat transport (inherited from Element1D):

dT = R * Q_flow

7. Remarks for Usage

Used inside ImpermeableLayer to represent vertical heat conduction in the confining layers. A resistance of R = 0 is permitted and yields no temperature difference, which is convenient for series connections. Thermal properties are taken from the Subsurface_Basic (Parameters) record.

8. Validation

Tested in check model "ATES.Validierung.Buoyancy.Val_homogenLayer"

9. References

(no remarks)

10. Version History

Model created by Markus Gillner (markus.gillner@tuhh.de), May 2026

Model revised by Markus Gillner (markus.gillner@tuhh.de), June 2026

- Completed the documentation (10-section template, preferred heading style) and corrected the interface description (heat ports port_a/port_b inherited from Element1D; A is a parameter, not a Real input).

Parameters

TypeNameDefaultDescription
SI.ThermalConductivitylambdaHeat Conductivity of the aquifer
SI.AreaA
SI.Lengthzheights of all control volumes in aquifer
SI.ThermalResistanceR0.5*z/(lambda*A)Thermal resistance of material

Connectors

TypeNameDefaultDescription
HeatPort_aport_a (from Element1D)
HeatPort_bport_b (from Element1D)

Components

TypeNameDefaultDescription
SI.HeatFlowRateQ_flow (from Element1D)Heat flow rate from port_a -> port_b
SI.TemperatureDifferencedT (from Element1D)port_a.T - port_b.T