Examining the Relationships between Stationary Occupancy and Building Energy Loads in US Educational Buildings–Case Study

Abstract

Building energy systems are designed to handle both permanent and temporary occupants. Permanent occupants are considered the base energy load while temporary occupants are considered a temporary or additional load. Temporary occupancy is potentially the most difficult to design as the number of temporary occupants varies more significantly than permanent occupants. This case study was designed to investigate the effect of occupancy on energy loads, i.e. the relationship between occupancy and building energy loads. This study estimated the building occupancy by using existing network infrastructure, such as Wi-Fi and wired Ethernet based on the assumption that the number of Wi-Fi connections and the wired Ethernet traffic were used as a proxy for total and stationary occupancy. The relationships were then examined using correlations and regression analyses. The results showed the following: 1. Stationary occupancy was successfully estimated using the network infrastructure; 2. There was a linear relationship between electricity use and total occupancy (and, thus, the use of network infrastructure); 3. Permanent occupants generated a higher impact on the electricity load than the temporary occupants; 4. There was a logarithmic relationship between electricity use and the Ethernet data traffic (a proxy of permanent occupants); and 5. The statistical and qualitative analyses indicated that there was no significant relationship between occupancy and thermal loads, such as cooling and heating loads.

A longitudinal study of the occupancy patterns of a university library building using thermal imaging analysis

“…However, Chen, Jiang, and Xie (2018) reported that BLE and Wi-Fi detection systems have limitations as the users may turn off Wi-Fi or Bluetooth on their devices and may have multiple devices. Lee, Chong, and Chou (2020) monitored stationary (such as faculty members and graduate students) and non-stationary occupants (such as students) in the Arizona State University building using Ethernet traffic flow and Wi-Fi connections, respectively. The authors noted the limitations of assuming occupant types solely based on whether they connect their devices to Wi-Fi or Ethernet.…”

A preliminary simulation study about the impact of COVID-19 crisis on energy demand of a building mix at a district in Sweden

“…This means that building energy and services systems (such as HVAC, lighting, plug-loads etc.) in residential buildings have to remain operating in order to provide energy, thermal comfort and ventilation even during weekends [14] . Conversely, offices and schools will have less internal heat gains and less operation time due to less occupants and by scaling back their activities, which will result in a drop of the energy demand especially during the weekdays.…”