Recently, the Advanced Research Projects Agency-Energy (ARPA-E) announced $20 million in funding for 15 projects that will develop a new class of sensor systems to enable significant energy savings via reduced demand for heating and cooling in residential and commercial buildings. The Center for Lighting Enabled Systems & Applications (LESA) at Rensselaer, along with the University of New Mexico (UNM) and LESA industry partner ABB, are working to create a low-cost, privacy-preserving sensor technology for counting, locating, and tracking occupants in any commercial space that will be developed and tested. Funding for the entire project is $2.375 million over three years.

Today, about 13 percent of all energy produced in the United States is used to heat, cool, and ventilate buildings, according to ARPA-E. Heating, ventilation, and air conditioning (HVAC) are the largest consumers of energy in commercial buildings, totaling 37 percent of all energy used in this sector. Much of this energy is wasted by heating, cooling, and over-ventilating unoccupied or partially occupied spaces. Due to a lack of accurate and reliable occupancy information, existing building automation and control systems are limited in their ability to substantially reduce HVAC energy use.

ARPA-E’s Saving Energy Nationwide in Structures with Occupancy Recognition (SENSOR) program supports innovative and highly accurate presence sensors and occupant counters that optimize HVAC of buildings while reducing cost and slashing energy use.

“The award from ARPA-E allows LESA to build on its fundamental research showing the power of digitized light, which, when reflected from any object in the space, generates privacy-preserving occupancy and activity data,” said Robert F. Karlicek Jr., LESA director. “In this program, the LESA team will apply its lighting toolkit concepts to achieving better energy efficiency in buildings, but this is only the start of how digitized illumination will become an essential part of any Internet of Things (IoT) platform for smart buildings, health care, horticulture, new 5G wireless communications, and cognitive environments. We are honored to work with our partners from the University of New Mexico and ABB to take our game-changing energy technology research to the next level.”

The technology uses only high-efficiency, low-power infrared LEDs and photodiodes for distance mapping, and with privacy preserved, can be used anywhere in the building. Studies of prototype occupancy sensing using this technology suggest that energy costs of heating and cooling can be reduced by up to 30 percent by training the building management system to deliver the right temperature air when and where it is needed. The data will also be invaluable for building utilization and security managers, simplifying the installation of new, energy efficient, smart building systems, and services.

According to Karlicek, the sensor significantly extends infrared-based time of flight (ToF) distance measurement technology previously developed by LESA. The new TOF sensor system will use a patented plenoptic (a light field that captures information about the light field emanating from a scene) detector technology developed by LESA academic partner UNM and will integrate additional sensor signal processing circuitry developed by the LESA optoelectronic illumination and communication team at Rensselaer.

“The miniature, low-cost ToF sensor array can then be built into lighting fixtures or installed in the ceiling,” Karlicek said. “In addition, several sensors distributed throughout the space will form a sparse network, scanning the entire space for distance information to map the precise number, location, and movement of occupants. In terms of identifying individuals, the sensors only register people’s presence in the space, thus preserving personal privacy.”

UNM will work on the development of a sensor array that provides multiple spatially separated time of flight signals using a unique integrated optical technology developed at UNM, which was recently awarded U.S. Patent 9,766,123 through STC.UNM. The UNM technology uses a grating coupled waveguide as a spectral and angular filter. The input coupling region is displaced from the silicon detection region to provide a unique plenoptic sensor that provides unparalleled spectral and angular resolution while being fully compatible with mature silicon integrated circuit manufacturing technology to ensure low cost.

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