HVAC Energy Savings and IEQ for Occupancy-Based Control by Side-by-Side
Experimental Study
Abstract
Building sensing technologies have evolved rapidly in the last two
decades in aid of monitoring building environment and energy system
performance. A series of occupancy sensing systems were developed to
track the occupant behavior in the indoor space. Occupancy-based
building system control is defined as a control method that adjusts the
building system operation schedules and setpoints based on the measured
occupant behavior and has been identified as a smart building control
strategy that can improve building energy efficiency as well as occupant
comfort. Some studies demonstrated energy-saving potential and
comfort-maintaining capability from occupancy-based control (OBC). This
study adopted a first-of-its-kind side-by-side experimental approach to
quantify the performance of the occupancy-based Heating, Ventilation,
and Air-Conditioning (HVAC) system control in commercial buildings.
Three state-of-the-art occupancy sensing technologies were integrated
into the real-time HVAC system control in this study. Their detection
accuracy and its effectiveness on energy-saving and thermal comfort were
analyzed. It was found that the OBC can maintain good thermal comfort
and perceived indoor air quality with a satisfaction ratio greater than
80%. Although the daily energy-saving by OBC varied with occupancy
sensor accuracy and outdoor environment conditions, the weekly averaged
HVAC energy saving was between 17-24%.