Light sensors have been on the scene, at least in rudimentary form, for years. The idea is a simple one: If lights can be more tightly controlled, their cost to operate will go down. The most obvious example is restroom lights that turn themselves on and off as people enter and leave.
The trend of the past few years is that modern telecommunications and IT technology is taking these technologies to new levels in a couple of ways. The most obvious is that they lower optional expense (opex). On a more subtle level, they collect data on how lighting, HVAC and other energy elements are being utilized by the building and the people within. This data can be proactive leveraged to make short- and long-term changes, predict and avoid potential problems and for other purposes.
Thus, occupancy sensors are one of the most valuable of these rapidly evolving tools. They often are co-located with or even integrated into LEDs. This is a good thing for energy managers, again for two reasons: The first is that lights are everywhere. There is no better way to get comprehensive insight into what is happening in a building than gathering data from the platform that is most widely dispersed. The other reason is that the evolution of these tools is happening while there is a change out of legacy lighting in favor of LEDs. That change out is almost solely due to the superiority of LEDs on environmental issues, energy usage and lifespan. This allows the advanced sensor capabilities to be icing on the cake as opposed to the main goal of a project.
Brent Protzman, Manager of Energy Information and Analytics at Lutron Electronics, told Energy Manager Today that commercial spaces have more distributed sensing options producing more data on how space is being utilized. “This growth in information from these sensors is driving the need to analyze this data and develop actionable insights,” he wrote. “For example, data on which office areas are occupied most, which ones the least, can help facility managers decide on an appropriate cleaning schedule, thus going beyond the use of light sensors as energy saving devices and into helping reduce operational costs."
It is difficult to put a definitive return on investment (ROI) and savings figure on such projects. The technology is used in different ways and is at varying levels of maturity. It seems, however, that the bottom line will benefit significantly. In March, The U.S. Department of Energy (DoE) posted an overview of the wireless approach to occupancy sensors. The first thing that the DoE does is make the overall case for the technology:
Studies have shown that adding lighting controls can reduce lighting energy use 10% to 90% or more depending on the use of the space in which the sensors are installed. One study conducted on a university campus found that installing wired occupancy sensors to control lighting in more than 200 rooms in 10 buildings provided an annual cost savings of about $14,000 with a simple payback of 4.2 years.
The piece outlines the approaches to wireless sensors. The good news for energy managers is that there are several wireless protocols that enable placement of standalone sensors without wired infrastructure.
The data will get deeper and more valuable, according to Protzman. “As sensors evolve, the types of devices will also evolve to get richer information for the facility managers and allow more environmental factors to be tracked with the intention of gaining greater comfort for the occupant in a space,” he wrote. “This could translate to sensing more than temperature, occupancy, and light.”
There has been a good bit of news on the motion sensor front.
Last week, Larsen Electronics introduced the EXP-MS-N4X-AT-HV explosion-proof motion sensor. It is aimed for use in hazardous (Class 1 Division 1 and Class 2 Division 1) areas. The wall-mounted unit is made of copper-free non-sparking aluminum and glass. The device is receommend for use in areas in which combustible dust and particles are present.
Two companies – Acuity Brands and Hubbell – made announcements regarding wireless capabilities of occupancy sensors. Acuity introduced the nLight AIR platform which, the company says, reduces complexity and cost in retrofit applications. In June, Hubbell said that it updated its wiSCAPE gateway, which control as many as 1,000 wiSCAPE fixture modules.
Research continues as well – and not just among vendors. For instance, the Lighting Enabled Systems & Applications (LESA) and students from Rensselaer Polytechnic Institution and Boston College were awarded a patent on a way to detect people’s presence, location and pose in a room without the use of cameras. This, the release says, is a way to collect granular data without compromising privacy.
Two evolution of occupancy sensors and the ongoing switch to LEDs can generate great benefits on both fronts – if companies savvy enough to combine the two.
