GEOTHERMAL ENERGY
Geothermal energy in multi-family housing: what we learned drilling 47 boreholes
Under the garden of the Arroyo Bodonal building in Tres Cantos there are 47 boreholes around 137 metres deep — more than 6,500 linear metres of drilling. You cannot see them, they make no noise and they burn no fuel: they are the heart of a geothermal installation that heats and cools 80 homes and produces their hot water all year round.
How geothermal energy works in multi-family housing
Geothermal systems take advantage of the fact that the ground keeps a stable temperature all year. A circuit of probes exchanges heat with the ground and eight cascading heat pumps (430 kW) raise or dissipate it according to the season: underfloor heating in winter, cooling in summer and domestic hot water at all times. The result at Arroyo Bodonal: an energy rating of A and a measured saving of 75% against a conventional building.
What you need to know before considering it
First, the ground decides: a preliminary geothermal study determines how many boreholes are needed and how deep they must go. The upfront investment is higher than a conventional system, and it pays back through running costs and through the value of a building that does not depend on fuel prices.
Is it repeatable today?
More so than in 2015: the equipment has improved, regulation is pushing towards nearly zero-energy buildings, and the volatility of gas prices has made energy independence more valuable. Our installation in Tres Cantos received the award for the best geothermal installation in the Community of Madrid, and it remains the benchmark we apply to the new residential developments we design across Spain.
Considering geothermal energy for a development or a house?
Tell us about it and we will explain what it would take in your case.