The pipe also is highly conductive which facilitates the extraction of heat from the soil. System fluid, water or water and antifreeze, is circulated through the buried pipe system, which absorbs heat from the earth and carries it to the heat pump. At the high school, the heat pump extracts heat from the pipes, compresses it to a higher temperature, and distributes it to individual heating-cooling units in each classroom. The individual units enable each teacher to determine individual classroom temperatures. Heat may be drawn from one classroom to a cooler one.
Unneeded heat is returned to the earth via the piping network.
The boreholes were then filled to the surface with bentonite grout, to bond the pipe to the hole walls and prevent air cavities from forming. The natural clay material seals the boreholes from bottom to top, to protect the integrity of the system and of nearby aquifers. It also provides a thermal bridge between the earth and the pipe. The school's system has two heat loop fields, each consisting of six well clusters or zones. Interconnecting the wells into one cluster took the crew eight to 12 hours.