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Other innovations 26/08/2019

The Cooling Island starts its season 2!

At a time when heat waves are common, people dream about their being outdoor in cool places set up in the heart of the city. This dream becomes a reality thanks to the Cooling Islands (Ilots Frais) connected to the City of Paris’s cooling network.These Cooling Islands were tested last summer on three sites. Now, they are coming back in four new locations. A few minutes of freshness with Maxime Boucaud (Project Leader for Climespace)!

How would you assess the summer of 2018?

To evaluate the Cooling Islands set up during the summer of 2018 (for the record, they were set at Gare de Lyon, Paris Plages and Station F), we created several tools.

  • Technical ones involving installing sensors on the Station F site to measure humidity levels, air temperature and light and allow us to compare the air next to the island to the air inside it. We verified that our objectives, namely reducing temperatures by 5 degrees inside versus outside the island) had been achieved. This data also fed databases on temperature, humidity, and light levels at specific sites in Paris.
  • An online survey linked to a QR code, whose low rate of return did not really allow us to exploit the data
  • And finally, "social" tools created with sociologists and ENGIE Lab Crigen. The sociologists spent several half days on each of the sites to observe the behavior of passersby, asking them about their perception of this new urban object. These investigations allowed us to better understand how people use the islands.

The first usage that has emerged is as a place to pass through to hydrate using the fountains set up by Eau de Paris on each site. On the square in front of Gare de Lyon, we had added seats to hide the network of pipes of the cooling network, which made it a central location where people could sit down without having to purchase anything.

Using the island as a meeting point was also frequently observed, especially on the Paris Plage site, a fairly large area, and at the Gare de Lyon, which is very busy.

For the Station F site, the typology of uses was quite different, in particular because there was a much smaller passage. It was more of a place for cigarette breaks.

To summarize, the islands gave people the opportunity to stop in areas where they would normally pass through, to sit, lunch, take a break, which met one of our objectives.

Finding areas for improvement

The study also identified areas of where work needed to be done, particularly because of a lack of clarity of communication. People did not necessarily understand how the island worked or what they were specifically for before sitting down.

We had some feedback on the base, which was considered insufficiently comfortable. That was one of our priorities for this year.

We got feedback on the feeling of freshness that were probably related to the lack of explanations and some technical problems. This has led us to develop a new technical solution for this year.

The good surprises involved the condition of the equipment at the end of the operation: neither broken nor degraded after three months, which means the device was very well received and accepted.

Starting at the end of the 2018 season we began working on new ideas for 2019 thanks to feedback on this first experiment.

So, what's new this summer?

This year we’re reformulating the concept of the Cooling Island that is connected to the city’s cooling network in two different ways: the iceberg and the oasis.

The oasis is an improved version of the device from last year. The iceberg involves new materials and different architecture. In both cases, air circulation is integrated for more homogeneous cooling under the island, removing the condensation which could appear at the bases. This development significantly increases the efficiency of the device and how users feel about it.

In return, you need electricity to run the fans and air circulation. To provide this electricity, we used different solutions for the oasis and the iceberg. For the oasis we use the cooling network, which recharges batteries at night using a turbine. These batteries are used to power the fans during the day. For the iceberg, the batteries are recharged by photovoltaic panels on the roof of the island.

So, there are two different islands in terms of energy supply, and also in terms of materials. On the iceberg the seats are made of granite, a material often used by the City of Paris, which is a good alternative to marble. Marble has very good thermal properties, but it is also more expensive and more subject to breakage. On the iceberg, the fresh air is spread through micro-perforations in the granite. In both cases, the basic principle remains the same: chilled water is used from the Climespace cooling network; it circulates in the device before being reintegrated in the cold network, without any water being consumed.

 A prototyping phase for better efficiency

To develop the "iceberg" version we did a prototyping phase on a smaller model and tested it in climate chamber at IFSTTAR. This modeling phase allowed us to improve the device before launching it at full scale. For the iceberg, we changed the opacity of the roof and made it adjustable to optimize ground coverage. Unlike the oasis, the iceberg cannot be modified, but it offers other ways to sit down or lean back.

The "oasis" version connects to other modules to increase its surface area, which is not the case with the "iceberg" version. So, we ultimately have a range that lets us adapt to different sites.

Comfort in the city, a central notion

We worked on the concept of comfort in the city and try to incite people to take the time to cool off.

Following last summer’s experience, the City of Paris, which works a lot on the subject of adapting the city to climate change, accompanied us during the design and installation phase, and included the islands in their Extrema app and the “cool path” through the city. It also created a communication panel that will be installed near the islands.