Despite the fact that commercial geothermal heat pump (often called ground-source heat pump or geoexchange) systems first gained moderate popularity as early as the late 1940s and early 1950s, widespread acceptance of the technology by architectural and engineering firms, mechanical design teams, developers, and building owner/operators has been extremely slow. And although there was a momentary increase in the installation of geothermal heat pump systems following the oil crises of the 1970s, it has not been until the past few years that interest in commercial geothermal heat pump systems has once again been on the rise