A residential building comprising 56 homes in San Sebastián de los Reyes, Madrid, uses a centralised geothermal system to meet its heating and cooling, and domestic hot water needs. Built in 2019, the building has 6,700 m² of conditioned floor area and combines three 25–100 kW water-to-water heat pumps, operating in cascade, with 32 geothermal boreholes, each 125 metres deep. Total installed capacity reaches 300 kW.

The system provides heating and cooling through radiant floor heating and cooling and is complemented by high levels of insulation and dual-flow ventilation with heat recovery. According to the case study, geothermal energy covers 100% of the building’s thermal demand. The system records a coefficient of performance of between 4.6 and 5 and an annual seasonal performance factor (SPF) of 5.3, which reached 6.7 in July 2023.

The source also reports savings of 36% compared with a conventional solution based on a gas boiler and aerothermal system, equivalent to €32,600 per year. The project also achieved one of the highest sustainability levels under BREEAM certification.

Key figures:

• Building condition: New building
• Building type: Residential building, 56 homes
• Delivery year: 2019
• Primary energy consumption: Not specified in the source
• Energy performance certificate rating: The source indicates the highest energy performance rating but does not specify the class
• Renewables: Geothermal energy through 3 water-to-water heat pumps; 32 boreholes, each 125 m deep; 300 kW total installed capacity; reported coverage of 100% of thermal demand