Heating, ventilation, and air conditioning (HVAC) consumes around 13 percent of all energy consumption in the United States. Much of this is wasted energy, used when buildings are either not occupied or occupied well under their maximum capacity. Traditional motion sensors are often used in buildings to adjust lighting levels, but they cannot provide advanced quantitative information about how many people are occupying the space, especially in an environment where people are stationary for long periods of time. Using monitoring systems like cameras or wearable sensors, however, may compromise occupants’ privacy.
Edwin C. Kan, Electrical and Computer Engineering, is leading a team of Cornell researchers to develop a privacy-conscious occupant monitoring system to enable more efficient control of HVAC systems in residential and commercial buildings. Their solution is based on a combination of active radio frequency identification (RFID) readers and cheap, passive tags. Instead of requiring occupants to wear tags—the tags as coordinated landmarks—are distributed around a room to enable an accurate occupancy count. Kan and his team have received $1.5 million in funding over 2.5 years.
When occupants, stationary or moving, are present among the RFID reader and multiple tags, their interference on the backscattering paths provides insights on the room population. Occupancy data are then sent to the building control system to manage HVAC in order to maximize building energy efficiency. Without breaching privacy, the smart thermostat technology can give reliable inputs to HVAC for energy savings larger than 30 percent, while improving human comfort and productivity.