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.
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.”
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.
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.