Date of Award
Master of Science
Anming Hu, Xiaobing Liu
Ground source heat pumps (GSHPs) possess great potential to become a mainstream technology for space heating and cooling due to their long service life and low operating costs. The main barrier for wider adoption of GSHPs is the high installation costs of ground source heat exchangers (GSHEs). These high costs are primarily due to the many steps and the associated labor, material, and equipment costs involved in the installation process. While some parts of the cost are generally fixed, such as wages of drillers; others can be lowered through advances in technology. As a result, it is important to extensively explore and evaluate potential solutions for lowering the installation costs.To reduce the installation costs, it was important to first identify the key cost drivers that have significant potential for cost reduction. A cost model originally developed at Sandia National Laboratories was updated with up to date costs and the accounting of various information associated with the installation process. A parametric study was conducted using this updated cost model to determine the effectiveness of various possible cost reduction solutions, which can then aid in identifying and targeting the key cost drivers to allow for the greatest cost reductions possible. Current technological advancements, primarily potential drilling technologies, were also researched to identify which technologies can be utilized to effectively reduce installation costs. Using this information, a guideline can then be created covering the potential solutions for reducing GSHEs cost under these conditions.From this study, several recommendations are made for lowering the installation cost. Minimizing the number of boreholes and maximizing the borehole length is the preferred option where available land for installing GSHEs is limited, but multiple shallow boreholes drilled with low-cost drill rigs may be better where available land is plenty. Despite which option is chosen, it is best to maximize the penetration rate of drilling and minimize the borehole diameter and associated material and equipment costs. Incorporating novel drilling methods, like the laser drill rig upon becoming economically viable, can also aid in lowering costs in places difficult to drill with conventional drill rigs.
McDonald, Joshua C., "Evaluation of Possible Solutions to Reduce Ground Source Heat Exchanger Cost. " Master's Thesis, University of Tennessee, 2018.