The effectiveness of heat transfer to the ground is a critical factor in designing efficient geothermal heat pump (GHP) systems. However, the thermal conductivity of the surrounding rock and soil formations is not the only factor to be considered. Borehole diameter, grout volume, and grout thermal conductivity also affect performance. To determine the relationship between each of these factors, tests have been conducted at several sites in Oklahoma, South Dakota, and Texas, using different grouts and varying pipe and borehole diameters to provide data that will allow installers to design more optimum and cost-effective GHP systems.

Units: Dual