Project file created by Ground Loop Design (GLD), an application used for designing ground source heat pump systems; includes design data such as an energy analysis, building heating and cooling capacities, costs, summary information, installation, and C02 (carbon dioxide) emissions. GLD project files are used to store pump system plans before installation. By default, they are saved in the work files directory of a GLD software installation. Ground Loop Design is available in Commercial and Residential editions.