Department of Energy

R&D 100: Smart Sensors Mean Energy Savings

July 23, 2013

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Researchers at the Energy Department's National Renewable Energy Laboratory recently developed a new smart occupancy sensor that adds optics to what had only been a motion detection before. The new sensor combines an inexpensive camera with a high-speed microprocessor and algorithms to detect movement and human presence in a room with an accuracy of more than 90 percent -- an advancement that could lead to enormous energy savings in commercial buildings. | Photo courtesy of Dennis Schroeder, NREL.

Researchers at the Energy Department's National Renewable Energy Laboratory recently developed a new smart occupancy sensor that adds optics to what had only been a motion detection before. The new sensor combines an inexpensive camera with a high-speed microprocessor and algorithms to detect movement and human presence in a room with an accuracy of more than 90 percent -- an advancement that could lead to enormous energy savings in commercial buildings. | Photo courtesy of Dennis Schroeder, NREL.

At an estimated cost of $38 billion a year, lighting represents the largest source of electricity consumption in U.S. commercial buildings. For nearly 30 years, commercial buildings have relied on motion occupancy sensors -- a technology that a study has found can only accurately detect people about 75 percent of the time -- to control lighting and reduce energy costs. But now researchers at the Energy Department’s National Renewable Energy Laboratory (NREL) have developed a new low-cost smart sensor that raises the accuracy of detecting people to the upper 90 percent range according to initial studies -- an advancement that could lead to enormous energy savings in commercial buildings.

How did NREL researchers achieve this dramatic increase in accuracy? They borrowed from a technology that most of us use on a daily basis -- the smartphone -- to go beyond mere motion detection and add optics to occupancy sensors. This breakthrough is so significant that the new sensor -- called the Image Processing Occupancy Sensor or IPOS for short -- was recently recognized by R&D Magazine as one of the 100 most outstanding technology developments of 2013.

The size of a stick of gum, IPOS combines an inexpensive camera with a high-speed microprocessor and algorithms to detect movement and human presence in a room. It can also count the number of people in a room, document their location and register their activity level with a potential range of up to 100 feet away. And because IPOS is based on mass-produced technology already on the market, it can be made economically. While IPOS is currently available for companies to license, researchers estimate it will likely sell for $100-200 when produced commercially.

But IPOS isn’t just a breakthrough for lighting controls. It also has the potential for use in regulating a building’s airflow for ventilation. Currently, buildings are required to provide the minimum amount of airflow necessary to supply ventilation for a fully occupied room even when no one is in the room. By counting the number of people in a room, IPOS could provide the information necessary to adjust airflow based on a room’s occupancy. When used to control both airflow and lighting, occupancy sensors similar to IPOS could cut a large building’s energy use by 18 percent on average, according to a new report from the Pacific Northwest National Laboratory.

Interested in more technologies that could change the way we use energy? Learn more about the other innovations from the Energy Department’s National Laboratories and facilities that won a 2013 R&D 100 award.