Effects of BTR on Required Bore Footage.
The curved lines show the required footage of a 5" bore per ton for a particular residential site. The vertical lines show computed BTRs for the various
loop types and for grout conductivities of 0.4 (blue lines) and 1.2 (red lines). The vertical positions of the loop types are for visual clarity only.
The required footage per ton is determined by the intersection of the vertical line, representing the BTR for the loop type and grout conductivity, and the Formation Thermal Conductivity (horizontal grid lines).