Comparative life cycle assessment of the ground source heat pump vs air source heat pump

In view of the decarbonisation of the thermal sector, the use of ground source heat pumps (GSHP) plays a key role. The geothermal system coupled with heat pumps, is the most energy efficient and environmentally sustainable heating and cooling system because the ground temperature is constant all year round, unlike traditional air-source heat pumps (ASHP). A comparative life cycle assessment of a pilot GSHP system, operating in the ENEA Casaccia Research Centre (Italy), and a conventional ASHP was performed. In accordance with ISO standard, the impacts on the four damage criteria were evaluated for each phase of the entire life cycle (production, installation, operation and end-of-life), using the SimaPro 9.0 software. The GSHP system has significant impacts compared to the other ASHP system components during manufacturing and installation. In contrast, slightly higher impacts of the ASHP system are recorded during the operational phase. It should be considered that the geothermal probe circuit has a useful life of 100 years, which allows for multiple operational life cycles of the geothermal plant. Therefore, the paper highlights that the GSHP system, as a whole, is more energy efficient and has a lower long-term environmental impact, compared to a traditional air conditioning system.