Water from Lake Annecy heats and cools the Trésums district in France

On 13 February, RES-DHC project partners visited a technical plant in Annecy that uses lake energy to provide heating and cooling to the nearby buildings.

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Lake Annecy serves as an energy carrier to heat and cool nearby buildings in the Trésums district (France).

This virtuous installation is based on a water loop supplied by the lake to cover, thanks to heat pumps, 95% of the heating and domestic hot water needs of occupants of 18 residential buildings, a senior residence, a hotel and the future municipal nautical centre. The water from the lake is also used to directly cool the buildings via exchangers and by a principle of geo-cooling, which saves electricity consumption in comparison to individual air conditioning systems.

This first lake heating and cooling network in France recovers 65% renewable energy by returning all withdrawn water back to the lake, thus preventing the release of 2,600 tons of CO2 per year.


This heating and cooling network has been built by IDEX.