Reflected Light Field Sensing for Occupancy Detection

APRA-E Project Image

New York
Project Term:
06/27/2018 - 06/26/2022

Critical Need:

Heating, ventilation, and air conditioning (HVAC) consumes a significant portion of the energy used in buildings. Much of this is wasted energy, used when buildings are either not occupied at all, or occupied well under their maximum design conditions. Traditional motion sensors are often used in buildings to adjust lighting levels, but they cannot provide advanced quantitative information about the environment. New classes of sensor systems used to enable advanced control of HVAC levels can include human presence sensors, people counting sensors, and low-cost CO2 sensors. Their improved accuracy and reliability can reduce energy consumption for homes and commercial environments.

Project Innovation + Advantages:

Rensselaer Polytechnic Institute (RPI) will develop a method for counting occupants in a commercial space using time-of-flight (TOF) sensors, which measure the distance from objects using the speed of light to create a 3D map of human positions. This TOF system could be installed in the ceiling or built into lighting fixtures for easy deployment. Several sensors distributed across a space will enable precise mapping, while preserving privacy by using low-resolution images. The technology is being designed around low power infrared LEDs and a patented plenoptic detector technology together with TOF information, which can enable unique combinations of spatial resolution, field of view and privacy. The sensor network will maintain an accurate count of the number of people in the space, and uses a simple program to track people who may be temporarily lost between sensor "blind spots", thus reducing the number of sensors needed. Occupancy data is then sent to the building control system to manage the heating, cooling and air flow in order to maximize building energy efficiency and provide optimal human comfort. Energy costs of heating and cooling can be reduced by up to 30% by training the building management system to deliver the right temperature air when and where it is needed.

Potential Impact:

If successful, SENSOR projects will dramatically reduce the amount of energy needed to effectively heat, cool, and ventilate buildings without sacrificing occupant comfort.


Lower electricity consumption by buildings eases strain on the grid, helping to improve resilience and reduce demand during peak hours, when the threat of blackouts is greatest.


Using significantly less energy could help reduce emissions attributed to power generation. In addition, improved interior air quality could help prevent negative effects on human health.


Buildings will require less energy to operate, reducing heating, cooling, and ventilation costs for businesses and families. In addition, better controlled ventilation may lead to improved indoor air quality (ensured by an accurate occupant count, and validated via widespread CO2 detection) may lead to improved worker productivity and academic performance


ARPA-E Program Director:
Dr. Marina Sofos
Project Contact:
Bob Karlicek
Press and General Inquiries Email:
Project Contact Email:


University of New Mexico
ABB, Inc.

Related Projects

Release Date: