This model simulates a borefield containing one or many single U-tube boreholes
using the parameters in the borFieDat record.
Heat transfer to the soil is modeled using only one borehole heat exchanger. 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.