You may not remember what you were doing on the evening of February 3, 2013. But Andrew Wilhelm does.
The President and CEO of the Oak Ridge-based LED North America was at home watching the Super Bowl between the San Francisco 49ers and the Baltimore Ravens. Shortly after the beginning of the third quarter, the power at the Louisiana Superdome went out. After the outage, the metal halide lights hanging from the Superdome rafters had to cool down, and warm back up. By the time the lights were illuminating the stadium at their pre-outage level, 34 valuable minutes had elapsed.
Wilhelm looked at the TV and said, “If they had LED lights, this wouldn’t take so long.” It was a moment that changed his life and will likely change the way University of Tennessee fans watch basketball for years to come.
For the last several weeks, Wilhelm’s company, along with Knoxville-based Bandit Lites, has been installing a revolutionary system of LED lights in UT’s Thompson-Boling arena, making it the largest sports arena in the country to use the technology on this scale. After the lights debut during Saturday's UT Men's Basketball game with Vanderbilt, Wilhelm predicts the new system will save the arena a lot of money on its energy bill, while offering fans an active, entertaining environment in which to watch a game.
Light-emitting diodes (LED's) are hardly new. They were invented more than a century ago, but languished largely unnoticed for the next fifty years. Starting in the early 1960’s, however, scientists began to explore LED’s and make significant improvements to the technology. Now, the lights are found in everything from televisions to car headlights and they’re rapidly becoming a popular way to light homes.
The technology’s introduction into sports arenas is much more recent. The reason arenas haven’t already adopted it involves the intense heat LED’s create. “Heat is the enemy,” says Wilhelm. “A lot of people don’t realize it, but LED’s get extremely hot. And the whole secret to the longevity and performance of LED’s is being able to manage that heat and move that heat.” Stadiums like the Superdome would have to incorporate enormous, expensive cooling equipment into their LED lighting systems to make it work.
After that fateful Super Bowl outage, Wilhelm began working with scientists at the Oak Ridge National Laboratory to find a more efficient way to keep LED lights cool. The answer came in the form of a graphite foam block, a technology invented by James Klett at ORNL in 1999.
“The graphite foam is basically a super thermal conductor of heat,” Wilhelm explains. “Technically, it’s pure carbon. It’s very, very porous. It’s 75% air, extremely lightweight.”
LED North America attaches a small graphite foam block to each 5-inch by 5-inch lighting board. When the LED’s on the board heat up, the foam absorbs it. And because the graphite is so efficient at dealing with heat, it only takes a small fan to cool it down. The smaller, lighter equipment will use up less space in the catwalk and will put less strain on the arena’s roof.
Just like the metal halide lights in the Superdome, the current lights at Thompson-Boling take a long time to cool down and fire up. So it’s not practical to turn them on and off. Over time, that adds up. Wilhelm predicts the LED lights will save the arena approximately 85% on its energy bill.
Even when the current lights go down for pre-game introductions, they’re not really going down. The system employs a series of drapes that shade the lights when it’s time for the arena to go dark. That archaic process limits the arena’s flexibility.
The LED’s being installed at Thompson-Boling, however, can be turned off and on again at a rate of approximately five times per second. Wilhelm says means the arena could be much more creative in the way it uses the lights. “You hit a button and the lights go out and one light lights up the American flag for the national anthem,” Wilhelm says. “And then they hit another button and the light instantly goes to light up the tunnel when the players come out. And then they go to the game, and boom—all the lights fire up. The Vols win the game, the lights start strobing, dancing all over the place.”
The fans will probably notice something about the arena has changed. But they may not be able to figure out why. “I don’t know if they’re going to notice the light,” Wilhelm says. “I think they’re going to say ‘Oh did Tennessee get a new court? This one’s like a white birch. They must have bleached it or used new wood’”.
And if the power at Thompson-Boling ever does go out during a game, fans won’t have to worry about a long delay. Once the power comes back on, the lights will come on too. And the game will continue.