Already solar, the road becomes heated

A brick is laid in the construction of the smart city. The road, of which the production potential of photovoltaic electricity is already being tested in real conditions by the company of public works Colas (Bouygues group) – including a stretch of about 1 km opened in December 2016 in Normandy by the minister of the Environment of the time, Ségolène Royal, discovers his capacity for heat storage. Eurovia, a subsidiary of Vinci specializes in the construction of transport infrastructure, was launched on Monday 16 October its new product Power Road : a road incorporating, in the upper layers of the pavement, a heat exchanger to recover the heat from the sun naturally retained by the bitumen.

“We add a new function to the road, and it becomes positive energy, while preserving the qualities essential to durability, safety, comfort, sustainability”, stresses the president of Eurovia, Stone Anjolras.

A heat captured in the summer and returned in the winter

Under the effect of the sun, the temperatures of the roads – which cover 1.2% of the surface area of metropolitan France, namely, the 6,500 square kilometres, can reach 60°C at the surface and 40°C to about ten centimetres deep. This heat is now untapped, and in urban areas it contributes severely, through the phenomenon of heat islands, global warming and pollution. The innovation developed after 4 years of research by Eurovia allows to capture more than 10%, claims the company, thanks to a system of tubes placed just under the road in which circulates a heat transfer fluid. This heat can then be stored via a system of geothermal energy coupled with the installation, and to be restored in the time of need, especially in winter, by a heat pump.

A parking of 120 spaces for a 25-metre swimming pool

If the first applications experienced by the company are on ice control and snow removal to road – based marketable and also to international airports, where operations winter viability can cost tens of millions of euros -, a variety of uses are appearing on the horizon. Thirty square metres of pavement made with Power Road would allow, for example, to ensure the full needs of heating and hot water to a housing surrounding 70 square meters, provides Eurovia, which is based on a variety of public and private partners, including Ademe and the office for studies in environment Burgeap. To heat a greenhouse farm of 1,500 square meters, it should be 500 metres of pavement wide of 7 metres. And a parking for 120 seats, equipped with Power Road would cover a third of the heating needs of a municipal swimming pool of 25 meters – with a pool and learning pool. Uses which, moreover, are cumulative, says director of marketing, Guillaume Malochet.

A reduction of fossil fuels

“Renewable Energie, this heat is picked up by the road can help to reduce the use of fossil fuels producing CO2″, emphasises Clara Lorinquer, director, Environment and Quality at Eurovia. Not to mention other advantage to the environment such as the replacement of the products de-icing, ” she says, insisting also on the recyclability of polymer-built-in Power Road. In summer, the heat storage allows in addition to reduce the surface temperatures of 60°C up to 25°C, with positive effects including the use of air-conditioning systems and the lifespan of the roads.

The need to use this energy at the local level, in the framework of micro-grid thermal, would improve the role – traditionally played by the road – link between territories and inhabitants, now connected to a renewable energy produced nearby, considers Eurovia. So much more that can be connected and contribute to the storage of other heat sources, local: energy recovery from waste incineration, data centers etc

Not a “niche product”

Without setting specific quantitative objectives, the company is hoping to roll out its new product in all 15 countries where it is present, with prospects particularly interesting in the countries of the East for snow shopping centres, ” she says. If the price remains vague, it will not exceed the double of the one way roads today, promises Peter Anjolras, saying it was “aware of the funding issues,” local authorities and saying that he does not want that Power Road is a “niche product”. It insists on its profitability, which is achieved in 10-30 years, i.e. the lifetime of the road equipped.

For the Moment, Eurovia pursues the tests, aimed at the scientific validation of the performance and the complete industrialization of the installation of Power Road. 500 square meters have already been fitted on a range of toll booth to the A10 (at Saint-Arnoult in Yvelines), where the employer Cofiroute operates the heat generated for the heating of its visitor centre to the public. The connection to a heat network is tested to Pontarlier (Doubs), where Power Road was installed to warm the surface of the parking lot of a high school, and where the heat used will be the result of the heat network of the city is fed by a waste incinerator. An experimental plot with an area of 3,000 square meters should still see the light of day in 2019, on a site still being defined.

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