Residential geothermal heating technology has been developed over the past few decades as an alternative to fossil-fuel based heating. However, the high initialization cost of these systems has proven to be a significant barrier to their acceptance. In order to reduce these initial costs, a better understanding of how the different pipe geometries and their orientations within a grout-filled borehole needs to be better understood. We are interested in formulating novel mathematical descriptions, utilizing the disparate length scales in the radial and axial directions, which can inform how different cross-section geometries, and geometrical variations in the axial direction affect the harnessing of energy from the soil. This problem is coupled to the thermal response in the soil, and hence both fields need to be found simultaneously.