In 2018, Charles de Gaulle Airport (ADP) has taken a step forward and chose to test the concept of saving energy linked to air conditioning thanks to a passive cooling: the cool roofing. A white paint that reflects the sun light waves during sunny periods was applied on the West Pier of the Terminal 2G. Over 1,160 square meter were covered with the CoolRoof paint from the Cool Roof France Company. The application required 10 days and two persons for the preparation of the roof/ coating application.
The coating system included:
- Two layers of base coat formulated with an acrylic based paint
- A top coat based on Kynar Aquatec® latex
Some fresh air before taking off?
The West (with cool roof) and East Pier (without cool roof) of Roissy airport were monitored by Surya Consultant to estimate the efficiency of the cool roof paint system in lowering the temperature at the surface of the roof. The temperature at the surface of the roof, the temperature of the ceiling above, and the ambient temperature were monitored from June 1 to September 30. A weather station also measured outside temperature (°C) and solar radiation (W/m²). During this period, the two Piers were air-conditioned used in similar conditions (passengers, traffic...).
The recorded data displays clearly the facts: the temperature of the passive cooled roof sharply lowered by 24.2°C and the energy consumption linked to air conditioning to reach desired settings inside building has seen a drop of 21% (6374 kWh, 5.5 kWh/m²). With actual energy price, this translates over the period to a saving of 612 Euros! In addition, employees working all day long inside the Pier have reported a great improvement in thermal comfort during this period, (as well as following years).
A dark roof absorbs most of the energy received by the sun, heating the roof structure and transferring most of heat flow to the underlying building or to the surrounding air: air conditioners that suck hot air and dump it outside can further exacerbate the cooling requirement of a building. The cool roof technology not only reflect as much of the sun’s energy as possible, but also affect surrounding temperatures and offset carbon emissions.
Desired long-Lasting whiteness
The goal of the project was to apply the best choice of architectural coating that would provide highly efficient reflectivity and long-term durability. The durability of cool roof paints made with Kynar Aquatec® latex has many advantages: it limits dirt, mildew and soiling accumulation on the slow-sloped roof from pollution and facilitates cleaning at a lower cost. The results: a white paint that reflects 95% of the sun rays whereas traditional paint reaches only 70%, and this for many years.