As anyone in the technology development sector knows, most of our working hours are spent solving the many problems that arise and thwart our path towards deliverable goals. Eventually we get there and make our clients happy with new products made possible through new twists of technology.
But what about all the effort spent on solving those problems? Is it a one-and-done exercise, or can all that learned-on-the-job knowledge be applied solving different problems for other clients? Our success with the LimeLight smart wireless lighting control system for parking garages proved to us that difficult problem solving experiences are never lost to the past. Working on a warehouse lighting project, we became more adept at networking hundreds and then thousands of sensors together with high-density mesh (HDM) infrastructures. Eventually, the question was posed: "where else can we apply this knowledge?"
That question was eventually answered by a "what if" thought one of our engineers had as he drove by an empty, but fully and brightly-lit parking garage at midnight. That's what planted the seed for LimeLight, a safe, controllable, extremely energy efficient parking garage lighting system.
First, let's consider the foundational elements (or constraints) of wireless lighting control for a parking garage. To begin with, we need a lighting fixture that combines optimal light output with the ability to dim on command and to turn on instantly when motion is detected. Next, these features had to be available at a price point that contributes to an attractive return on investment, which required that our optimal fixture be fluorescent.
Applying what we learned from the smart lighting warehouse project, we turned lights into intelligent fixtures by attaching a two-way radio to each. This enabled the lights to communicate with each other and ultimately to talk to a gateway serving as the central nervous system of the mesh. The gateway is tied to the Internet, and all the lighting commands, schedules, and events are managed via the Web through someone's office or laptop computer.
This combination of easy system management with energy savings of as much as 65% is just the beginning of LimeLight's benefits. Because each fixture is intelligent, all kinds of garage performance functions and problems can be monitored through the mesh network. For example, if a fixture is vandalized, an email or text message is sent instantly identifying which one has been damaged. Messages also are immediately sent identifying burned out lamps or other malfunctions.
Each LimeLight lamp fixture incorporates a motion sensor, creating redundant coverage throughout the entire floor. With these sensors, light harvesting is optimized during the day and at night. Light pollution is also eliminated by dimming the fixtures in the evening when the sensors detect no motion from either vehicles or people. Any fixture can be dimmed to a single lamp, turned off, or go to full power.
Most importantly, the system provides safety. When movement of either a person or vehicle is detected, groups of lighting fixtures switch to full power, providing a safe and inviting nighttime experience. Furthermore, LimeLight safeguards the entire garage, ensuring that no matter when a customer may enter the garage, the system will light the way. Fixture groupings allow an entire floor to illuminate once motion is detected at the entrance. As cars exit the facility, each floor below will illuminate ahead of time.
LimeLight sensors calibrate the light output during the day, minimizing energy consumption while creating a pleasant environment with natural light. Between the savings from adjusting lighting levels during the day and the energy conserved by turning off the lights when they aren't needed at night, the energy meter on these parking structures turn at a snail's pace while creating an ROI that turns heads. Installed in a parking facility at the University of Michigan, LimeLight reduced electrical costs by 60% in its first year of operation and saved the university $32,000. Not only is the system providing better on-off control of lighting, it has reduced basic electrical requirements through its ability to convert previous 250 W fluorescent fixtures to 102 W devices.
To summarize, LimeLight is a Web-based control system that operates through high-density mesh (HDM) wireless technology. User-programmable parameters determine who accesses the system and at what level they operate. Two-way communication between system components is enabled by an nPhase M2M platform. A gateway mini-computer manages the lighting fixtures by leveraged Zigbee protocol to enhance data communication in the often hostile environments of parking facilities. Fixtures include radio modules integrated with motion sensors to facilitate communication and light harvesting and all are managed through the Web-based customized user interface.
The hard work it takes to solve tough problems today can keep paying dividends down the road. In our case, the lessons we learned by solving warehouse lighting problems is now helping municipal and university parking garages in 16 states to reduce their electrical usage through the evolution of LimeLight.