Computational Occupancy Sensing System (COSSY)

Heating, ventilation, and air conditioning (HVAC) consume a significant portion of the energy used in buildings. Much of this energy is wasted when buildings are occupied well below their maximum capacity. Traditional PIR (passive infrared) sensors, that detect movement, cannot estimate the number of people in a room. While COsensors can provide a proxy measurement of occupancy level (inferred from COconcentration), their response to changes in occupancy is very slow on account of long time scale of air mixing. Clearly, a new type of sensor system is needed to enable advanced control of HVAC infrastructure. Deployed in commercial buildings, such sensor systems have the potential for a significant reduction in energy consumption in the US and the associated reduction of COemissions.

A team composed of faculty and students from the Departments of  Electrical and Computer Engineering, and of Mechanical Engineering at Boston University is currently developing a Computational Occupancy Sensing SYstem (COSSY) to estimate the number of people in commercial spaces and monitor how this number changes over time. The system is being designed to deliver robust performance by combining data from thermal door sensors and overhead fisheye cameras. Data streams from the sensors and cameras jointly undergo advanced detection to provide an accurate occupancy estimate. All processing is performed locally within a building’s infrastructure (no processing in the cloud) to mitigate security concerns.  The system will feature a modular design to accommodate various room sizes and geometries (scalable architecture). The obtained occupancy data will be sent to the building autoamtion system (BAS) 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 a BAS to deliver the right-temperature air when and where it is needed.


The project is currently in an early stage as various COSSY components are being developed and compared with state of the art. For a detailed description of current research, please see the following links

This project is expected to help reduce the amount of energy needed to effectively heat, cool, and ventilate buildings without sacrificing occupant comfort or privacy.

  • Economy: Buildings will require less energy to operate, reducing HVAC costs for businesses. In addition, better controlled ventilation may lead to improved indoor air quality and increased worker productivity.
  • Security: 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.
  • Environment: 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.