In 2015, commercial and residential buildings accounted for 40% of the energy consumption in the United States according to the U.S. Energy Information Administration. As the owners of these buildings seek to decrease costs and reduce energy consumption they have begun to adopt building energy management systems (BEMS). BEMS have developed alongside intelligent building technologies such as sensors and wireless networks to manage energy usage, and according to expert services firm Navigant, the global BEMS market is expected to grow at an estimated CAGR of 18.2% to $12.8 Billion in 2025.
Occupancy sensors are an important component of BEMS, allowing buildings to reduce electricity consumption by managing HVAC systems, plug loads, and lighting during times of low or no occupancy. Research firm Markets and Markets predicts that the global occupancy sensor market will grow at an estimated CAGR of 19.5% to $2.78 Billion in 2020. However, current occupancy sensors have high upfront costs, are vulnerable to false triggering, and use energy themselves, which has limited their adoption to only very large commercial buildings. Overcoming these hurdles is critical for the next generation of BEMS and the reduction of building energy consumption.
Researchers at NREL have discovered innovative ways to use a building's existing Wi-Fi network to determine occupancy within the building. Taking advantage of the beamforming characteristics of modern routers allows occupancy to be determined by tracking the signal direction and strength of wireless device connections within a building. Techniques developed at NREL can also be used in tandem with existing hardware to determine occupants and occupant density in three dimensions by actively and passively measuring the Wi-Fi characteristics of a space. These solutions allow building occupancy to be determined with low upfront costs and negligible additional energy usage compared to traditional solutions, expanding the BEMS market to a wide variety of commercial and residential buildings.
Among the advantages of this system are that it uses an established hardware platform, with which building owners, occupants, and customers are comfortable; it enables occupancy-based control for the roughly 98% of buildings that do not currently have it. It has low energy consumption with increased occupant counting accuracy and real-time occupant tracking.