Ground source coil drilling platform - Annulus drill: Final report

Abstract

Ground source heat pumps (GSHPs) use geothermal energy to heat and cool the operating fluid to pass through heat exchangers to condition the interior environment of commercial and residential structures. While GSHPs are usually more efficient than traditional heating/cooling systems, the up-front costs are high and the installation process can be very invasive to retrofit applications, which is a large part of the GSHP market.

The goal of this design project is to design a system capable of drilling a large annulus for installing a coil of HDPE pipe for heat transfer in a ground source heat pump system. Given dimensions of the annulus hole are 3 feet, 2.5 feet, 15 feet for outer diameter, inner diameter and depth, respectively.

The design of the machine performs two primary functions: annulus drilling and earth extraction. The purpose of drilling an annulus rather than a hole is to reduce the amount of dirt removed from the ground to lessen the installation costs and environmental effects, and to reduce the depth drilled into the ground from around 250 feet to 15 feet. This project is designed to reduce the overall environmental effects and cost of installing a ground source heat pump. The constraints include leaving the smallest possible footprint in a resident's yard, making the system easily operated by a trained individual, and reducing the cost of the operation and also the machine itself.