A new day dawns in La Défense. The first tired employees emerge from Line 1 of the Paris Metro, and the skyscrapers of La Défense awaken, bright lights coming on one by one behind the glass façades. But cooling tower manu­fac­turer Jacir has already accom­plished much of his work on this January night in 2019. On Jacir’s orders, heavy goods vehi­cles had crawled through the empty streets in the early hours – twelve stain­less steel boxes, each 7.6 to 7.7 meters, were unloaded in front of a building that resem­bles an upside-down mush­room: the heart of enertherm, respon­sible for all the hot and cold running water in La Défense.

enertherm is respon­sible for heating the homes and work­places of hundreds of thou­sands of people to a suit­able temper­a­ture. enertherm uses a piping system to provide cold water for air condi­tioning and warm water for heating directly to the build­ings.

But first, there were prob­lems to solve. The cooling towers in enertherm’s produc­tion plant were past their best. They are used to cool the condensers that conduct the heat from the water. enertherm had to contend with leaks, and main­te­nance was compli­cated. And then there was the noise – the nearest resi­den­tial and commer­cial build­ings are only 50 meters from the plant, which was too close for the level of noise that the old towers made.

In three stages, Jacir’s cooling tower experts installed 36 custom-built cooling towers under the roof of the enerthem building. (Photo | enertherm)

36 Custom-Made Cooling Towers

This is where Jacir really impressed. The cooling tower experts are based in Pontault-Combault in the south-east of Paris and won the tender to deliver enertherm 36 custom-made cooling towers, to be installed under the roof of the enertherm building in three stages. To Antoine Robi­chon, Jacir’s Tech­nical Director, it is clear what made the differ­ence. “For enertherm, it wasn’t the price that was key – as we weren’t cheaper than the compe­ti­tion – it was how quiet our product is. On paper, our strongest competitor’s system was equally quiet, but ours delivers in prac­tice. ebm-papst’s calcu­la­tions proved to be absolutely correct.”

Jacir installed a total of 324 RadiPac fans with a size of 1,000 millime­ters in the cooling towers for enertherm. (Photo | enertherm)

If you stand 20 meters away from the Jacir cooling towers, you’ll be exposed to a volume of 37 dB(A). That’s less than a TV in your living room playing at a normal volume. Each cooling tower contains nine fans, which generate an air flow of 270,000 m³/h. “We chose ebm-papst’s RadiPac centrifugal fans, as they were the only ones that could meet the require­ments,” says Robi­chon.

324 Fans

Apart from the low noise level, the two main require­ments were energy effi­ciency and being wear free: The fans have a wide optimum effi­ciency range, with a static overall effi­ciency of up to 68 percent. The EC external rotor motors of the centrifugal fans with 100% speed control do not require main­te­nance thanks to the long-term lubri­ca­tion of the ball bear­ings. With the new cooling towers, enertherm can achieve a total cooling capacity of 129 megawatts. In total, Jacir installed 324 RadiPac fans with a size of 1,000 mm in the cooling towers for enertherm.

The project was divided into three deliv­eries, each of twelve towers that Jacir had to install on the roof of the enertherm building at a height of five meters – which was no easy under­taking, and a real orga­ni­za­tional effort: “The heavy goods vehi­cles were only allowed to operate at night, while the 1,000-ton crane was only able to work in the day. What’s more, the crane driver couldn’t see what was happening at the end of the 100-meter-long arm,” Robi­chon explains.

But the posi­tioning of the cooling towers worked out – and strength­ened Jacir’s posi­tion in the market at the same time: “It was an impor­tant project for us. We will keep making use of the newly devel­oped tech­nical possi­bil­i­ties in the future,” says Robi­chon.