With this system, geothermal energy is collected by means of a brine circuit and transferred to the heat pump. Geothermal brine collectors can be installed in three different ways: where there is sufficient land available, horizontal collectors are the most affordable option. The area covered depends on the method of construction and thermal insulation level of the building, as well as ground conditions. A spiral-shaped trench collector would be an alternative that takes up less physical space. Geothermal probes which require deep boreholes , can also be set into the ground. These are typically set to a depth of 100 metres each, and are ideal when little space is available. In many locations, these require a permit from the local water board.
Active or passive cooling: In active cooling mode, heat is "pumped" from the building interior in summer using the existing heating system and transferred to the ground. In active cooling mode, the maximum cooling capacity will still be available, even after several weeks of hot weather. Engineering information