This model computes the different thermal resistances present in a single-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.
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.
function internalResistancesOneUTube extends IBPSA.Fluid.Geothermal.Borefields.BaseClasses.Boreholes.BaseClasses.Functions.partialInternalResistances; output Modelica.SIunits.ThermalResistance Rgb "Thermal resistance between grout zone and borehole wall"; output Modelica.SIunits.ThermalResistance Rgg "Thermal resistance between the two grout zones"; output Modelica.SIunits.ThermalResistance RCondGro "Thermal resistance between: pipe wall to capacity in grout"; end internalResistancesOneUTube;