COVID-19 is changing the way indoor spaces are used, presenting challenges for those who manage those spaces, from homes to offices and factories. Not least among these challenges is heating and cooling — the largest consumer of energy in American homes and commercial buildings. There’s a need for smarter, more flexible climate control that keeps people comfortable without heating and cooling entire empty buildings.
Researchers have developed a solution that could provide more efficient, more personalized comfort, completely eliminating wall-mounted thermostats. The Human Embodied Autonomous Thermostat (HEAT) pairs thermal cameras with three-dimensional video cameras to measure whether occupants are hot or cold by tracking their facial temperature. It then feeds the temperature data to a predictive model that compares it with information about occupants’ thermal preferences. HEAT determines the temperature that will keep the largest number of occupants comfortable with minimum energy expenditure, effectively and efficiently maintaining the comfort of 10 occupants in a lab setting.
HEAT is able to measure comfort without requiring users to wear any detection devices and without the need for a separate camera for each occupant. It works a bit like today’s Internet-enabled learning thermostats. When it is newly installed, occupants teach the system about their preferences by periodically giving it feedback from their smart-phones on a three-point scale: “too hot,” “too cold,” or “comfortable.” After a few days, HEAT learns their preferences and operates independently.
The research team is working with power company Southern Power to begin testing HEAT in its Alabama offices, where test cameras will be mounted on tripods in the corners of rooms — the cameras would be placed less obtrusively in a permanent installation. The cameras collect temperature data without identifying individuals and all footage is deleted immediately after processing, usually within a few seconds.
Facial temperature is a good predictor of comfort since blood vessels expand to radiate additional heat, raising facial temperature; when we’re too cold, they constrict, cooling the face. While earlier iterations of the system also used body temperature to predict comfort, they required users to wear wristbands that measured body temperature directly and to provide frequent feedback about their comfort level.
Tweaks to the model could make the system useful in hospitals, where care providers struggle to stay comfortable under masks and other protective equipment. The HEAT system could be adapted to help them stay comfortable by adjusting room temperature or even by signaling to them when they need to take a break.