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\ndecades in aid of monitoring building environment and energy system performance.\nA series of occupancy sensing systems were developed to track the occupant\nbehavior in the indoor space. Occupancy-based building system control is\ndefined as a control method that adjusts the building system operation schedules\nand setpoints based on the measured occupant behavior and has been identified\nas a smart building control strategy that can improve building energy\nefficiency as well as occupant comfort. Some studies demonstrated energy-saving\npotential and comfort-maintaining capability from occupancy-based control (OBC).\nThis study adopted a first-of-its-kind side-by-side experimental approach to\nquantify the performance of the occupancy-based Heating, Ventilation, and Air-Conditioning\n(HVAC) system control in commercial buildings. Three state-of-the-art occupancy\nsensing technologies were integrated into the real-time HVAC system control in\nthis study. Their detection accuracy and its effectiveness\non energy-saving and thermal comfort were analyzed. It was found that the OBC\ncan maintain good thermal comfort and perceived indoor air quality with a satisfaction\nratio greater than 80%. Although the daily energy-saving by OBC varied with occupancy\nsensor accuracy and outdoor environment conditions, the weekly averaged HVAC energy\nsaving was between 17-24%.