The light bill for big stadiums can be significant -- After all, the light bulbs used to illuminate playing fields are typically metal-halide and burn 1,500 W each. So you might think an upgrade to illumination-grade LEDs would be a natural idea for stadium operators. The problem has been that LEDs haven't had enough output to handle field lighting chores. But that situation is changing. The first LED fixtures billed as being "stadium capable" were introduced last year.
The most recent development in the solid-state stadium lighting area was the development by Noribachi in Los Angeles of a new light engine that incorporates an array of 378 individual LEDs said to deliver up to 66,000 lumens of light. The new product is available both as a custom LED light engine, called the 378.HEX, and integrated into a fixture designed for stadium illumination.
Will the new LED engines be up to that task of brightening stadiums? Here's how Noribachi analyzes the issue: Most major league sports arenas, the company says, require more than 50 foot candles of illumination on the field of play. And the number of lights in a stadium can vary greatly from 250 to over 1,000. The 378.HEX light was designed to mimic the 1,500-W metal halide bulbs normally used in field lighting. A brand-new metal halide bulb is capable of generating anywhere between 75,000 and 150,000 lumens. This output is omni-directional and must be reflected onto the field. Based on reflectivity, the actual illumination beamed at field is somewhere between 52,500 to 105,000 lumens.
At least on paper, the Noribachi engine should be able to handle field lighting. The company says its 1,500-W-equivalent stadium and flood light requires only 450 W of power to operate but generates about 75,000 lumens — all of which are directed at the field. Noribachi says it gets this kind of performance by narrowing the "beam angle" of the LEDs to 80º.
Noribachi also says its LEDs do better than ordinary 1,500 W playing field lights partly because 1,500-W lights get dimmer relatively quickly — a metal halide light can see a decrease in lumen output by 40% in as little as a year. That's not an issue for LEDs. Noribachi is claiming its LED engines last three to five times longer than the conventional lamps they replace.
The Noribachi light engines typically sport a power factor greater than 0.9 and approximate the color output of metal halides bulbs as well.