I wrote the below news item for the September issue of tED Magazine. Reprinted with permission.
High- and low-bay luminaires are common in industrial applications such as warehouses and manufacturing but also certain commercial applications such as big-box stores. “High bay” frequently refers to luminaires mounted at a height over 20 feet, “low bay” up to 20 feet. Due to the greater distance between the luminaire and the task, more light output is required—commonly 5,000 to 20,000 lumens per low-bay luminaire and 15,000 to 100,000 lumens per high-bay luminaire.
According to the U.S. Department of Energy (DOE), industrial luminaires represented 15 percent of all lighting energy consumption in 2015. These luminaires represent a significant amount of wattage and have long operating periods (at least 12 hours per day), making them a suitable candidate for replacement by more-efficient LED alternatives. DOE estimated LED penetration at six percent of this market in 2015, showing plenty of room for growth.
How do these LED alternatives perform? A new DOE CALiPER Snapshot Report profiles current average performance among LED industrial luminaires targeting incumbent HID and fluorescent technology. The results are based on more than 8,000 applicable products listed in the Lighting Facts database.
The report suggests strong improvement in this Lighting Facts category between April 2014 and March 2017, with big gains in light output while wattage remained fairly steady, resulting in an efficacy (lumens/W) increase. Mean efficacy was 115 lumens/W, a 20 percent improvement. In comparison, the mean efficacy of metal halide and fluorescent luminaires is around 70-90 lumens/W. This category is also more efficacious than linear, troffer, area/roadway and parking garage luminaires listed in Lighting Facts. In fact, Lighting Facts’ most efficacious product is a 22,000-lumen high-bay luminaire operating at 210 lumens/W.
Efficacy for about two-thirds of the products exceeded 105 lumens/W, the threshold for inclusion in the DesignLights Consortium’s (DLC) Qualified Products List (QPL). At the high end, about a quarter of the products were rated over 130 lumens/W, the threshold for DLC QPL Premium listing.
DOE found that a majority of the Lighting Facts-listed industrial luminaires emitted comparable light output as their metal halide and fluorescent counterparts. Mean light output was 18,000 lumens, far exceeding the DLC QPL minimum requirement of 5,000 lumens. About one-half produced 11,000-22,000 lumens. About two percent, or 150 products, emitted more than 50,000 lumens, which is able to match the output of 1000W metal halide luminaires.
Color quality for the Lighting Facts-listed industrial luminaires was similar to that of their conventional counterparts. About one-half offered a correlated color temperature (CCT) of at least 5000K, which is a very visually cool shade of white light. A significant portion of the remainder had a CCT of 4000K, with some available at 3000K and 3500K. About two-thirds of the luminaires offered a color rendering index (CRI) rating in the 80s, with most of the rest having a CRI in the 70s.
“In terms of the data captured by LED Lighting Facts and reported in the new Snapshot, LED industrial products offer a compelling alternative to incumbent products,” James Brodrick, DOE SSL Program manager wrote in his April 12, 2017 SSL Postings. “While the report focuses on basic photometric characteristics, choosing a product for a specific installation requires a more comprehensive analysis, including light distribution, projected lifetime, lumen maintenance and cost.”
Click here to read the report.