Neal D. Paul

Document Type

Thesis - University Access Only

Award Date


Degree Name

Master of Science (MS)

Department / School

Mechanical Engineering


The objective of this research was to determine the effect of grout thermal conductivity on the design and performance of vertical geothermal heat exchanger loops. The steady-state grout thermal resistance was found experimentally and b using A SYS finite element analysis modeling. A multiple regression model was developed from the experimental results. The ANSYS results were correlated to using shape factors. Grout thermal resistance values from the experimental model were used with software packages GchpCalc and GLHEPRO, and the IGSHP A vertical loop design equations to estimate the effect of grout thermal conductivity on design loop length. Total loop length reductions of up to 15% to 25% were found. The effect of grout conductivity on vertical loop installation costs was estimated by comparing designs from GchpCalc for regular bentonite grout and for grout containing 50% sand for thermal enhancement. For a 15% reduction in heat exchanger design length a 14.2% cost savings was estimated for the heat exchanger installation. It was also shown that, for a given heat exchanger design􁅑 use of thermally enhanced grout instead to regular bentonite grout will result in better heat pump performance and lower operating costs.

Library of Congress Subject Headings

Heat pumps -- Design and construction Heat -- Transmission Grouting (Soil stabilization)



Number of Pages



South Dakota State University