The availability of Light-Emitting Diode (LED) fixtures with integrated sensors and embedded controls is relatively new and not implemented at scale in Department of Defense (DoD) facilities. The increased use of LED lighting, with the addition of integrated controls, will help DoD reduce energy use and energy costs. The goal of this project was to demonstrate and accelerate the deployment of an innovative holistic lighting retrofit system in DoD facilities. The project evaluated the demonstrated lighting system in terms of the installation and commissioning process, measured energy and demand savings, light levels, installed cost, system economics, and occupant satisfaction.

Technology Description

The demonstrated lighting system employs LED luminaires available in typical form factors. Each fixture is equipped with a passive-infrared occupancy sensor, a light sensor for daylight harvesting control, and a communications and control module. Switches use a wireless network protocol to communicate with fixtures. Luminaires in the group respond together to both switch operation and to occupancy signals. Each fixture adjusts for available daylight independently. Additional savings may be realized by trimming the high-end output of each luminaire.

Demonstration Results

 This demonstration project used LED lighting technology with integrated occupancy and daylight sensors and embedded controls. The potential energy savings may be estimated by comparing against typical fluorescent lighting installed at a lighting power density of 1.2 W/ft2. An LED system would have a lighting power density (LPD) on the order of 0.6 W/ft2, reducing energy use by 50%. The additional use of occupancy control and daylight harvesting can cut remaining energy use by 38%, resulting in total savings of about 69% of the original energy use.

The table below lays out other performance objectives and success criteria measured in this project.

EW-201722 Table


Implementation Issues

The general trend is decreasing installed cost for these systems. As this trend continues, the overall economics of these lighting systems will naturally improve. However, the following may help expedite this within DoD facilities. The installed cost at the demonstration sites was much higher than expected. This involved several factors: installation time, fixture density, and markups. The higher-than-expected labor hours may be due to the small areas associated with the sites. Fixed costs do not scale with site size, making it more advantageous to pursue lighting retrofit of larger areas (>25,000 ft2 ). It is also important to obtain buy-in from the occupants. This similarly involves educating them about the benefits of the system and the basics of its operation.