Validating the Digital Lumens LED Lighting Control Retrofit
Bryan Urban | Fraunhofer USA Inc.
The objective of project EW-201718, is to validate the lifecycle energy and cost savings potential of an automated Light Emitting Diode (LED) lighting retrofit system in up to four typical Department of Defense (DoD) facility types, including high-bay (hangar, warehouse/coldstorage, big-box retail) and office applications. In addition, researchers will demonstrate the technology is relevant and appropriate for the target end-use applications, that it is compatible with DoD requirements, and that lighting output that meets or exceeds pre-retrofit conditions.
A successful project will demonstrate 1.) lighting energy savings of at least 70% (stretch target 90%) relative to typical non-controlled non-LED lighting systems, 2.) simple payback of under five years with at least 5x ROI, 3.) average fixture install time of 15 min., and 4.) occupied lighting levels at least as high as pre-retrofit condition or meeting American National Standards Institute (ANSI)/ American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) standards.
Although LED lighting is proven to reduce energy consumption, several barriers prevent its widespread adoption and effective use in many retrofit applications. Providing intelligent lighting controls is a common pain point, as most existing fixtures in DoD facilities lack the communications and sensing to accommodate adjustable lighting control. Traditional solutions require expensive and invasive rewiring that make installations of control systems impractical. Furthermore, in high-occupancy environments, basic lighting control methods do not lead to significant reductions in energy usage.
Smart lighting controls can unlock energy efficiency gains that go beyond simple lamp efficiency improvements. Digital Lumens® has developed the Intelligent Lighting System with Connected Light Engine (CLE, for high-bay applications) and LLE Linear Light Engine (LLE) Fixtures (for linear tube fluorescent retrofits). This innovative lighting platform reduces lighting energy consumption, simplifies installation, eliminates maintenance, and enables centralized control and automation. At the network level, the luminaires communicate via encrypted wireless ZigBee® mesh network to a central hub, and the luminaires can be controlled, programmed, and polled from either the central hub, a control panel, or a handheld device. The platform integrates electrical sub-metering to provide detailed reports of lighting energy use to verify and improve energy savings over time. Occupancy reports that log when lights are switched on can provide a security benefit.
Validation will use independent circuit-level monitoring and data from the Digital Lumens® systems to verify energy savings and to confirm the ability of the lighting system to measure and report its energy performance. Light and occupancy data loggers will be used to monitor and normalize for activity and ambient light availability and to record pre- and post- retrofit conditions. Time to install will be recorded during the retrofit. Surveys will measure occupant and facilities personnel acceptance and satisfaction.
Lighting accounts for about 22% of commercial buildings electricity consumption, and electricity consumption accounts for about 64% of DoD’s facility energy bill. Initial field testing of the retrofit system found up to 93% energy reduction over existing lighting systems (high-bay) and 43% over existing uncontrolled LED solutions. Facility savings (per 100,000 ft2) can exceed $27,000 per year.
Assuming an average energy savings of 80% relative to fluorescent tube or sodium lamps without controls is applicable to 70% of lighting end uses, the lighting system would reduce DoD’s $4 billion facilities energy expenditure by about $390 million per year. This represents about 10 percent of total facility energy expenditures.
Non-energy benefits include commensurate reductions in facility electric demand, improved lighting quality, increased resiliency, and reduced operation & maintenance costs.