The history of under-soil heating
69,256 fans in a sold-out stadium including VIPs from the fields of politics, sports, and entertainment. The marching band plays the Olympic hymn, cable pullers try to beat a path through the crowds for the new, roaming cameras being used for the first time …
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Radio journalists and photographers rush from one interview to the next, and high above the field in the television booths, the moderators can hardly contain their enthusiasm: “We’re up here right now with what is most likely the best stadium lighting system anywhere in the world, looking down on a pitch that’s bright as day, and we can hardly believe it,” the moderator of German broadcaster ZDF explained to a viewership still mostly sitting in front of black-and-white televisions. “This stadium is a technological masterpiece.”
A stadium without equal
It was May 26, 1972. Germany would take the field to play against the USSR for the opening of the new Olympic stadium in Munich. And it was a big day not just for sports, but also for politics and the nation’s self-image. That’s why only the very best — including the stadium’s sophisticated roof design — would do for this symbol of national pride. The evening turned out to be a triumph: Germany beat the superpower Soviet Union 4:1. Gerd Müller shot every single goal. A report on the game published in the Soviet Union remarked: “Gerd Müller, known as the ‘Bomber of the Nation,’ seemed to be everyplace at once,” And as an aside: “The field was even heated.”
And it was true — not only had the engineers conceived an automated sprinkler system and lighting that put out a total 1,875 lux across the entire 105-meter length and 68-meter breadth of the playing field — to this day one of the brightest stadium lighting systems in Europe — they had also installed the very first under-soil heating system in the world beneath the grass. “Utterly ludicrous!” exclaimed Munich’s evening paper: “The old saying heard from parents around the world ‘I’m not paying to heat the outdoors!’ gets a whole new meaning.” But they also admitted that the new system “might have certain advantages.” And clearly it did. But it would take a long time for other football clubs to recognize them. A full 15 seasons of bitter cold winters later, the managers of Frankfurt’s football team had heating lines installed under the pitch of their Waldstadion arena.
Today, under-soil heating is required by Germany’s football association, the DFB, for the country’s top two leagues. Because it reduces the risk of serious injury to players as result of falling on the rock-hard frozen ground, but also because the grass regenerates faster thanks to the heat provided from below. And football is big business. When games are canceled, it can put a big dent in club finances.
The perfect conditioners
Under-soil heating systems require a ton of energy, frequently up to 50% of the average total energy consumption of the stadium. One thing that helps keep energy consumption in check is ensuring good heat transfer and system efficiency. From a physical standpoint, water is the best solution thanks to its high specific heat. But pure water will corrode the metal and plastic components of the system. And if it gets too cold, it freezes — expanding with enormous strength and destroying the lines. If you add glycols to the water, it won’t freeze anymore, but you will reduce the heat transfer performance and specific heat capacity.
“That makes finding the right conditioners in the right concentration no easy task,” explains Dr. Frank Hillerns of TYFOROP Chemie GmbH in Hamburg. Because the list of characteristics that a good heat transfer fluid must have is long: “It needs to ensure efficient heat transfer and protect against frost and corrosion. It needs to be compatible with all the metal and plastic components in the system including materials used to manufacture seals and also be able to handle extreme thermal stress in either direction. It has to be non-toxic, environmentally safe, and offer good value for the money.”
On May 14, 2005, Germany’s Olympiastadion shut down for good. After 33 years, 1,120 games, and a final victory against Nuremberg, the players of FC Bayern München celebrated their 19th title as Germany’s national champions while saying goodbye to the field on which they achieved their finest moments. At the very same time, the lines were being laid for the heating system of the new Allianz Arena’s field. On a substructure consisting of 4,500 m³ of frost-proofing gravel, 27 kilometers of flexible heating line as thick as your thumb was installed and filled with several thousand litres of TYFOCOR®. The field can now be heated using temperatures as high as 50°C. The 8,000 m² of grass has had to be replaced eleven times since then. The heating system, however, is still running flawlessly. “Of course that’s mainly because of the good work the heating installer did,” says Hillerns, “but we also play a part in ensuring that the games go off without a hitch.”
TYFOCOR®-brand products for heating, air-conditioning, and ventilation
Central air-conditioning systems in large buildings provide heat in the winter and cooling in the summer. To accomplish this, the heat transfer fluid in the central air-conditioning system is either heated or cooled and then transported to the heat exchangers in the individual rooms through piping. The heat transfer fluid used has to live up to all the demands placed on it regarding heat transfer and corrosion protection over an extended period of time and under both high and low temperatures. Even in buildings at remote locations which are not heated the entire winter through, our products prevent the heating system from freezing and thus ensure a long, trouble-free service life.