Wi-Fi based Occupancy Detection in a Building with Indoor Localization

This paper presents the implementation of Demand Controlled Ventilation (DCV) System of a building. Particularly in dynamic environments, the occupancy of the zone is frequently varying with respect to time. The objective is to design-energy-efficient ventilation system without affecting the occupant's comfort, by knowing the number of occupants in the building, where they are located and their behavior. The conventional CO2 based DCV system requires multiple CO2 sensors to monitor the indoor air quality. The delay in obtaining responses from the sensor leads to poor accuracy in real-time implementation of CO2 based DCV system. In this paper, the indoor occupancy densitiesat different regions are approximated by implementing logging counter based on the Received Signal Strength Indicator (RSSI) of Wi-Fi. The distance between the transmitter and the mobile Wi-Fi devices can be measured and located in the indoor environment from the values of RSSI. Continuous tracking of mobile Wi-Fi devices will give the occupancy pattern of the zone. These occupancy pattern of the zone will improve the performance of the building HVAC (Heating, Ventilation and Air-Conditioning) Systems.