Water and gas consumption, how Grasse intends to save money for its municipal swimming pool

Wednesday 20th November 2024 02:56 AM

Efforts in terms of energy transition are underway.

If the Urban Community of the Pays de Grasse (CAPG) has already lowered the temperature of the Harjès swimming pool by one degree (that's 7% savings!), this is not the only measure to reduce the bill .

For the past two weeks, the historic Grasse basin, opened in 1984, has been equipped with a state-of-the-art system for the automatic renewal of water and the recovery of calories from waste water.

Because they are subject to hygiene and safety standards, swimming pools are required to regularly renew their bathing water, i.e. 30 liters per day per bather. “In Harjès, which welcomes 57,000 users per year, 1,700,000 liters have to be changed each year, not counting the effects of evaporation and overflowing water,” explains Julien Jamet, director of waste and energy management at the Agglo.

15.000 euros savings per year

What is this new concept implemented by Véolia Énergie? This is the Axone exchanger, patented by the Onsen company, which won the 2021 Environmental Trophy. It collects hot renewal water (29°C) and captures the calories from this water, which allows to preheat the new water. As for the water to be evacuated, it is collected in a 15m3 tarpaulin semi-buried in front of the building, and will be reused for washing the filters.

So, what savings for the CAPG? The result is 750,000 liters of water saved, or €2,900 per year.

But also 148 MWh saved per year, or 22% of annual gas consumption, i.e. €12,580. In total, a reduction in costs estimated at more than €15,000.

For what investment? “The cost is €92,280including 62% subsidies from the State and Energy Saving Certificates”, specifies Charlotte Pruvot, head of the energy department at CAPG, which therefore financed €35,030.

“The advantage is that this equipment can be installed at Altitude 500 when it reopens,” underlines Annie Duval, elected for energy savings at the CAPG and in Grasse. The future Altitude 500 nautical center (hopeful opening in 2026) will be equipped with a wood boiler and solar thermal system.

The Harjès swimming pool will then permanently close its pool…

In the technical room, the Axone exchanger, which recovers heat from the waste water.

The number

34
This is the number of tonnes of CO2 saved each year thanks to this system. This system is already in place at the Oliviers swimming pool in Cannes, and in a pool in La Ciotat, in Bouches-du-Rhône.