CH-24-C010 - Implementation of RP-1747 Demand-Controlled Ventilation in an Office Building: Preliminary Results from the Cooling Season

ASHRAE RP-1747 is a CO2-based demand-controlled ventilation (DCV) approach which uses trim and respond logic to dynamically adjust variable air volume (VAV) terminal units’ minimum airflow setpoints based on zones’ ventilation requirements. While simulation results and laboratory testing have estimated the impact on heating, ventilation, and air conditioning (HVAC) systems compared to traditional ventilation, there have been limited applications of RP-1747 in occupied, real-world buildings to date; indeed, its adoption by ASHRAE Guideline 36 is pending “further confirmation of its stability in real-world applications”. This paper introduces a real-world implementation of RP-1747 DCV in an institutional office building in Ottawa, Canada, and examines concurrent HVAC energy and building automation system (BAS) data from the highly instrumented building during the cooling season. Occupancy and CO2 data are compared to evaluate per person delivery rates of ventilation air and CO2 concentrations in zones before and after the implementation. Three-parameter univariate changepoint models are used to compare the HVAC energy use in the months before and after the implementation. Challenges with the implementation, including errors in the case study buildings control logic, are detailed and their implications on the study’s findings are discussed. The results represent a preliminary attempt at implementing RP-1747 in a real building, with an aim to contribute to the body of literature on this emerging DCV approach and provide anecdotal evidence of its benefits and iterations with other control logic in a real-world application.