Why Louvre’s Mona Lisa keeps a smile

PARIS (AP):

The Mona Lisa may maintain her famously enigmatic smile because she benefits from one of Paris’ best-kept secrets: An underground cooling system that’s helped the Louvre cope with the sweltering heat that has broken temperature records across Europe.

The little-known ‘urban cold’ network snakes unsuspecting beneath Parisians’ feet at a depth of up to 30 metres (98 feet), pumping out icy water through 89 kilometres (55 miles) of labyrinthine pipes, which is used to chill the air in over 700 sites. The system, which uses electricity generated by renewable sources, is the largest in Europe — and chugs on around the clock with a deafening noise totally inaudible above ground.

Paris City Hall has now signed an ambitious contract to triple the size of the network by 2042 to 252 kilometres (157 miles). It would make it the largest urban cooling system in the world. The new contract intends to help the city to both adapt to and combat the threat of global warming. Many parts of Europe hit 40 degrees Celsius (104 Fahrenheit) in July.

The city is extending the cooling network to hospitals, schools and metro stations over the next two decades. It’s unclear how much of the system will be operational by the time of the Paris Olympics in 2024, but it’s possible the systems will be used in several Olympic sites.

Unbeknown to millions of tourists, the piping currently cools the City of Light’s most emblematic sites, such as the Louvre and the Quai Branly Museum. It might even help cool the tempers of agitated lawmakers as it is used to drop temperatures in the National Assembly.

JOINT VENTURE

The scheme is operated by the joint-venture company Fraîcheur de Paris — 85 per cent owned by the state’s French energy company EDF and the rest by public transport operator RATP. The company’s officials tout its benefits for the entire French capital.

“If all (Parisian) buildings get equipped with autonomous installations (such as air conditioning), it will gradually create a very significant urban ‘heat island’ effect,” said Maggie Schelfhaut of Fraîcheur de Paris, referring to the increased heat in cities due to less vegetation, which cools, and more urban infrastructure, which absorbs the sun’s rays.

But Schelfhaut said that the pipe network could make the whole of Paris one degree Celsius (1.8 Fahrenheit) cooler than if autonomous installations were put up across the city.

“One degree less in the city centre is a lot,” she added.

Three of the 10 high-tech cooling sites lie on the Seine river and are accessed by a retractable spiral staircase barely visible from street level — in something resembling the lair of the ‘Teenage Mutant Ninja Turtles’.

When the Seine’s water is cold enough, a machine captures it and uses it to chill the system’s water. The heat created as a by-product is sent back into the Seine, where it is absorbed. The chilled water is then pumped though the system’s pipes to its 730 Parisian clients.

Paris’ cooling sites all use renewable energy sources, such as wind turbines and solar panels. Four new solar energy sites which will feed into this network are also earmarked for construction. French officials see this energy independence as particularly important, given the threat of Russia cutting off energy supplies to Europe.

The merits of using a cooling system which uses renewable energy to operate are already being felt by sites that use them. The world’s most visited museum, the Louvre, has benefited from the network since the 1990s — with officials proud of its ecological, economic and art-conservation advantages.