The Lighting Research Center (LRC) at Rensselaer Polytechnic Institute has issued a new DELTA report on mogul-base light-emitting diode (LED) replacement lamps. These high-wattage lamps are designed to fit into the large mogul sockets found in commercial, industrial and outdoor lighting applications to replace conventional, high-intensity discharge (HID) lamps. LED replacement lamps have the potential to save substantial energy, reduce maintenance and improve color characteristics.

In 2015, LRC’s DELTA Program Director Jennifer Brons conducted an evaluation of mogul-base LED replacement lamps at the Bonneville Power Administration (BPA) Maintenance Facility, a warehouse and shop for electrical utility workers, serving southern Oregon. The space is used for storing vehicles, electrical equipment and supplies. The facility is also occasionally used on nights and weekends for repair or assembly tasks and for weather-related electrical emergencies. The original lighting (metal halide lamps) was installed when the facility was built in the early 1990s. The LRC conducted an evaluation of the lighting before and after retrofit with mogul-base LED replacement lamps.

The field test objectives were to:

-Assess ease of retrofit
-Compare worker acceptance before and after retrofit
-Compare energy performance before and after retrofit

Key findings of the DELTA report include:

-Power demand of the LED retrofit was 60% lower than the conventional metal halide luminaires, without reducing light levels or creating hotspots underneath.
-The retrofit increased light levels noticeably, compared to the existing degraded metal halide lamps with dirty lenses. Because lights were also turned off more frequently after the retrofit, higher energy savings (73%) were estimated.
-Payback periods were long, but might be shorter at other sites with longer hours of use, higher electricity rates, or lower-cost LEDs.
-Instant restrike characteristics of LEDs provide opportunities for other energy-saving technologies, such as vacancy/ occupancy sensors or time clocks.
-The electrician had positive feedback about the installation experience.
-Worker feedback about the retrofit was enthusiastically positive.
-Workers preferred re-use of existing prismatic diffuser lenses, rather than leaving retrofitted luminaires open.

“The LED replacement lamps demonstrated at this BPA facility direct the light downward, delivering the light to a horizontal workplane more effectively than the previous metal halide lamps,” said Brons. “LED lamps such as these have the potential to illuminate high bay environments at equal or higher light levels, with lower power demand.”  

“The old lighting was inefficient and often required maintenance,” said Jennifer Williams, project manager, with BPA’s Facilities Planning and Projects. “The new LEDs improve employee safety and working conditions, and are much more energy efficient.”

“The project turned out great and is much appreciated,” said Craig Sanders, BPA facilities maintenance worker and project supervisor. “The installation was very straightforward. We were able to do 21 individual replacements in about a day’s time.”

The project was made possible through a partnership with BPA’s Emerging Technologies team.

The full-color, illustrated report, Mogul Screw-base LED Replacement Lamps for High Bay Environments, detailing the project evaluation and findings, is available for free download from the LRC website.

Other recent DELTA reports include LED Lighting in a Campus Building, LEDs for Construction Lighting and Daylighting in Whole Foods Market.

About DELTA
Since 1994, the DELTA program, which stands for Demonstration and Evaluation of Lighting Technologies and Applications, has produced more than 40 case studies at sites ranging from schools to office buildings to senior housing, along with numerous outdoor locations. The reports are written for lighting specifiers, building managers, architects, and others who design and install lighting, and are available for free download from the LRC website.