Genilac is a 100% renewable innovative thermal solution, using lake water to cool and heat buildings in the centre of Geneva, Switzerland.

Cold water is pumped from the bottom of the lake into a network of pipes and buildings. The water runs through the interior of buildings to cool them down during summer, removing the need for AC units in places like office buildings and data storage facilities.

Diagram:

Source: https://iglus.org/genevas-new-urban-energy-infrasystem-connectivity-for-sustainability/

In winter a heat pump heats the water before it enters buildings, using the lake water to heat buildings. This solution offers an 80% reduction in CO2 emissions for heating and cooling in comparison to traditional methods.

In summer, 80% less energy is needed for the cooling process.

See their youtube video

Sources:

Genilac youtube channel: https://www.youtube.com/user/ChaineSIG

Genilac website (all information is taken from here)

Truchet, Thierry. “GENILAC: A Major, Sustainable Energy Innovation for Geneva.” Genie.ch, 17 June 2021, https://www.genie.ch/project/h/genilac-a-major-sustainable-energy-innovation-for-geneva.html.