BuildSysPro.IBPSA.Fluid.Geothermal.Borefields.BaseClasses.Boreholes.BaseClasses.Functions.internalResistancesTwoUTube

# .BuildSysPro.IBPSA.Fluid.Geothermal.Borefields.BaseClasses.Boreholes.BaseClasses.Functions.internalResistancesTwoUTube

Thermal resistances for double U-tube, according to Bauer et al (2011)

## Information

This model computes the different thermal resistances present in a double U-tube borehole using the method of Bauer et al. (2011). It also computes the fluid-to-ground thermal resistance Rb and the grout-to-grout thermal resistance Ra as defined by Claesson and Hellstrom (2011) using the multipole method.

#### References

J. Claesson and G. Hellstrom. Multipole method to calculate borehole thermal resistances in a borehole heat exchanger. HVAC&R Research, 17(6): 895-911, 2011.

D. Bauer, W. Heidemann, H. Müller-Steinhagen, and H.-J. G. Diersch. Thermal resistance and capacity models for borehole heat exchangers. International Journal of Energy Research, 35:312–320, 2011.

#### Interface

>     function internalResistancesTwoUTube
>       extends IBPSA.Fluid.Geothermal.Borefields.BaseClasses.Boreholes.BaseClasses.Functions.partialInternalResistances;
>       output Modelica.Units.SI.ThermalResistance Rgb "Thermal resistance between a grout capacity and the borehole wall, as defined by Bauer et al (2010)";
>       output Modelica.Units.SI.ThermalResistance Rgg1 "Thermal resistance between two neightbouring grout capacities, as defined by Bauer et al (2010)";
>       output Modelica.Units.SI.ThermalResistance Rgg2 "Thermal resistance between two  grout capacities opposite to each other, as defined by Bauer et al (2010)";
>       output Modelica.Units.SI.ThermalResistance RCondGro "Thermal resistance between a pipe wall and the grout capacity, as defined by Bauer et al (2010)";
>     end internalResistancesTwoUTube;

## Revisions

- February 7, 2022, by Michael Wetter:
  Changed function to be `pure`.
  This is for IBPSA, #1582.
- December 11, 2021, by Michael Wetter:
  Added `impure` declaration for MSL 4.0.0.
- July 18, 2018 by Massimo Cimmino:
  Implemented multipole method.
- February 14, 2014 by Michael Wetter:
  Added an assert statement to test for non-physical values.
- February 12, 2014, by Damien Picard:
  Remove the flow dependency of the resistances, as this function calculates the conduction resistances only.
- January 24, 2014, by Michael Wetter:
  Revised implementation.
- January 23, 2014, by Damien Picard:
  First implementation.

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