The objective of this project is to quantify the energy, environmental, and economic benefits of deploying advanced exterior lighting control technologies at a representative U.S. Army installation (Fort Sill, Oklahoma). Three complementary systems based on scalable control and communication technologies will be demonstrated, each targeting different exterior lighting applications (e.g., street lighting, parking lots, and vehicle maintenance areas) and offering different levels of functionality, energy, and maintenance cost savings. The system solutions deployed will be tailored to suit the unique characteristics of the target Department of Defense (DoD) applications. Evidence will be gathered to substantiate energy savings, payback time, performance, and reliability of these systems, and the results will be used to estimate broad DoD benefits.
The Dynadimmer system is a standalone fixture-by-fixture control architecture where the light level is controlled by a preprogrammed dimming profile as a function of time by a controller integrated in the LED driver. This configuration enables energy and cost savings by dimming the light levels during periods of low occupancy.
Starsense is a radio frequency mesh networked system where each light fixture is controlled independently using an Outdoor Lighting Controller (OLC) module placed on top of the LED fixture. The OLCs are set to a programmable dimming profile, and the entire lighting network is displayed on a remote dashboard allowing remote visualization and control of the system at all times. A lighting management service software called CityTouch is provided to allow easy interaction, detailed asset management functions and fault detection, energy usage reports, and real-time control.
The LOD system is based on the Starsense mesh network and adds motion detection sensors in the network allowing dynamic adaptive control of the light levels in each fixture. System configuration software allows flexible deployment of the sensors and light fixtures as well as asset management, energy reporting, and extensive data visualization features.
With the Dynadimmer system, energy and cost savings of 66% (exceeding the objective of 50%) were achieved on 36 LED luminaires over the demonstration period of 1 year in an administration building parking lot (Welcome Center B4700). Average illuminance level was slightly increased (2.0 footcandles [fc] versus 1.8 fc), and distribution uniformity was substantially improved (7.4 versus 168) over pre-retrofit.
The Starsense was deployed on a main road through the base (Sheridan Road) on 40 LED luminaires and achieved energy savings of 59% (exceeding objective of 50%) over 1 year of operation. Average illuminance was increased from 0.5 fc to 0.7 fc on roadway sections and 1.2 fc at intersections, and distribution uniformity was substantially improved (3.7 versus 42) compared to pre-retrofit conditions.
Deployed in a TEMF with 42 fixtures, the LOD system replaced HPS lamps with LED light fixtures. The new system demonstrated energy savings of 92% (exceeding the objective of 50%) while maintaining the same average illuminance with improved uniformity (1.9 versus 10.6) over pre-retrofit conditions.
In all three systems, the lighting levels exceeded Illuminating Engineering Society of North America illuminance requirements. User feedback from questionnaires showed overall satisfaction with the new lighting and a clear preference for the new system compared to the pre-retrofit HPS lighting based on functionality and convenience.
Based on the results, Fort Sill is considering deploying these systems (specifically the Starsense system, which is a commercially released product). Several thousand Dynadimmer systems have already been deployed to over a dozen Air Force bases. At this time, the LOD system is a research prototype and is being considered as a future product.
This project has shown that advanced LED light sources with controls can result in substantial energy and cost savings (60 to 90% depending on the application areas and usage patterns) while improving the quality of light in terms of color rendering and brightness, which has been confirmed by user surveys. Life cycle cost analysis has shown that these systems can provide savings to investment ratio (over 20 years) of more than 2.0 and payback of less than 5 years for Dynadimmer and LOD and less than 8 years for Starsense in areas where the average cost of electricity is $0.10 or more per kilowatt hour (kWh). Electricity rates vary between $0.044 per kWh to $0.28 per kWh across the United States for industrial customers and are higher for commercial and residential customers. Furthermore the actual rates are determined by negotiations between base administration and the utility companies.
Deployment of these exterior lighting systems has already been carried out, or is being considered, at several other Department of Defense (DoD) bases, including multiple Air Force bases, Fort Bliss, Fort Knox, Fort Dodge, and others. The results from Fort Sill have been helpful in understanding DoD needs in depth, which allows for wider deployment across DoD thereby enabling substantial energy and cost savings. Beyond energy related costs, the asset management features allow detailed information on the usage of the lighting infrastructure, which can be combined with data analytics to provide improved space utilization resulting in added cost savings.