Europe’s largest office tower in La Défense saves electricity

Esave electricity without using candlelight: the Coeur Défense tower in La Défense (Hauts-de-Seine), Europe’s largest office complex, reduces its consumption thanks to new devices and a lot of gray matter to control the building through sensors.

“Energy efficiency has been talked about for three to four years,” says technical director Ludovic Levavasseur, 52, who supports the change, with around 40% less consumption between October 2021 and October 2022.

Invisible in the report, because the price of kW has increased in parallel, the reduction will continue, especially thanks to the thousands of presence detectors gradually installed in the 170,000 m2 offices, he assures.

These automatons communicate hour by hour, day by day, with a computer in a modest blind room in the basement overseen by 42-year-old Nicolas Puype.

With service provider Engie Solutions, he has been the building’s “energy manager” for three years.

Coeur Défense’s seven buildings employ between 6 and 7,000 people, with a downward trend due to telecommuting.

Without seeing them, Nicolas Puype witnesses the ballet of arrivals and departures, which are immediately transmitted to the building’s technical management system (TMS).

“I know everything that’s going on without moving, I don’t even need a camera,” admits the automation engineer, who goes so far as to guess which train people take to get to work.

On its screens, elevators rise, lights turn on, fans start, and the power consumption curve rises, then collapses at the end of the day.

It turns off automatically when the desktop is empty.

Nicolas Puype neither dictates the temperature nor regulates it remotely, but he has an eye.

On the screen to his right, all energy production is synthesized, the slightest anomaly is reported.

Color graphs are superimposed, today’s consumption, previous day’s consumption.

All the sensors in Coeur Défense and the computers monitored by Nicolas Puype ultimately have a simple mission: to heat and light only when workers are present.

“If you’re already consuming only what you need to consume, you’re safe,” comments Thierry Chambon, CEO of Energisme, which sells energy management software.

All electric

The skyscraper, known for its twin 40-story towers with rounded edges reaching 161 meters high and bay windows that form a shifting white checkerboard, is 80% occupied.

It is impossible to turn off the heating or air conditioning, of course, to open the windows.

Pulsating hot or cold fresh air depending on the season to breathe, 42,000 lighting points, 76 elevators, 11 escalators, 14,000 blinds, more than 8,000 fans, etc. need to be equipped.

Everything is electric. Safety generators start in the event of an outage.

Thus, the electricity bill is the second cost item for the tower after security and fire safety.

And with prices rising, Mr. Puype is the man: “Here’s the liner. Once it drifts, it’s a little late to catch up, so I watch it day by day,” he said.

In 2021, the heat recovery cooler was replaced under the building.

A material that produces all the heat and cold the tower needs, the city grid serves only as a backup.

This equipment was commissioned in 2001. It’s new, it’s more efficient, and it’s this investment that has allowed electricity consumption to drop dramatically over the past year.

The expected reduction of 10% to 15% for next year will be easier: “We will try”, assured Frédéric Galvez, Deputy General Manager of Property Management at BNP Paribas Real Estate, which manages 2,000 buildings in France, including Coeur Défense. does.

Insulation remains. “It would be a huge, monstrous investment, almost as much as the price of the building (1.8 billion euros bought in 2017, editor’s note),” he says. “It would require the entire building to be demolished, the tenants to leave, and the owner to have no income during construction.”

For now, the tower is thinking more about equipping itself with photovoltaics.

23/12/2022 09:25:26 – Paris (AFP) – © 2022 AFP

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