http://www.youtube.com/watch? v=bsBvxw3W8bM
Schedules have been used in HVAC systems for decades to predict building occupancy. Office buildings, for example, are generally only occupied weekdays. During nights, weekends, and holidays, reducing ventilation, heating, and cooling down to their bare minimums saves considerable energy costs over continuously running them at full capacity.
A study on Norwegian schools found that using IR motion sensors to control DCV systems reduced energy consumption by 49% when compared with a standard CAV system.
CO2 sensors are popularly used to measure occupancy level. In a survey on Norwegian schools, using CO2 sensors for DCV was found to reduce energy consumption by 62% when compared with a constant air volume (CAV) ventilation system.
Studies have been conducted concerning the feasibility of using acoustic sensing and processing to control building automation. In October 2011, a project began, partially funded by the European Commission under grant no. 284628 Sounds for Energy-efficient Buildings (S4EeB). It is investigating the feasibility of DCV through monitoring sound in buildings to determine the occupancy level.
Studies have been conducted concerning the feasibility of "people counting" via inexpensive video cameras and software to compute occupancy levels of rooms. http://www.youtube.com/watch? v=bsBvxw3W8bM
