Increasing the Efficiency of HVAC Systems using Schedule-Based Control

Heating, Ventilation and Air Conditioning (HVAC) systems maintain the temperature and air quality in buildings. In many commercial buildings, HVAC systems run on a simple schedule that maintains a comfortable temperature during the workday while conserving energy at other times. However, it is possible to conserve even more energy if the information on the level of occupancy is available. This is the case, for example, in classrooms at post-secondary campuses where explicit timetables for classroom usage can be available. In this paper, the viability of using classroom timetables as a data source is explored to create a more efficient schedule for HVAC system usage. Software to extract timetable data and then generate an HVAC schedule based on this data was developed. Schedules are generated and implemented in three different buildings. A reduction in energy of 20.8%, 20.3%, and 30.7% was observed for each building respectively by comparing energy consumption two weeks prior to and two weeks after implementation. This is evidence that schedule-based HVAC control can be used to effectively reduce total building energy consumption.