Harnessing low-temperature geothermal resources

The operating principle of a geothermal system involves combining a geothermal energy source—which captures thermal energy from the ground—with a heat pump-type thermodynamic system to raise the temperature of the thermal energy, and a distribution network within the building. A key feature of this system is its ability to produce heat (heating, domestic hot water— –, DHW) and cooling (cooling and air conditioning) depending on the season and needs.

These so-called low-temperature geothermal systems are used in industrial and commercial buildings as well as in residential buildings, improving the building’s environmental performance and, consequently, its green value.

A simplified scheme known as “minor geothermal energy” (GMI) has been established to promote these facilities, provided that the following conditions are met:

• drilling depth of 200 m;

• thermal power recovered throughout the entire facility < up to 500 kW.

This guide is intended to help you develop a project from design through to operation; starting from the design phase, you must identify the project’s characteristics as accurately as possible (heating and cooling requirements to be met, temperatures of the geothermal resource, temperatures of the building’s heat emitters, etc.). In addition, care must be taken to optimize all energy-consuming components (auxiliary systems) to achieve an optimized installation that meets the needs and comfort requirements of building occupants. The choice of installation type must, of course, comply with regulatory requirements, and, as with many other technologies, the search for financing can rely on the CEE programs.