Empirical evaluation of an occupant-participatory schedule-based control for GHP cooling systems

• We empirically evaluated a participatory HVAC control strategy over 3 months. • The strategy cut indoor unit operating time by 38.8% compared to a fixed schedule. • M&V analysis of field data verified a 9.7% net decrease in GHP gas use. • Operational data reveals a 26.9% building vacancy, acting as a diagnostic tool. This study presents an empirical evaluation of an Occupant-Participatory Schedule-Based Control (OPSBC) strategy for a gas engine-driven heat pump (GHP) cooling system in a commercial office building. Unlike conventional schedule-based control (CSBC), OPSBC integrates a brief pre-cooling period with occupant-initiated operation, effectively using occupant behavior as a zero-cost occupancy sensor. A field experiment was conducted in a five-story office building in Daejeon, South Korea, with CSBC applied from July to August 2024 and OPSBC from August to September 2024. Indoor unit operational data were analyzed to assess changes in runtime and load, while a measurement and verification (M&V) framework was used to quantify GHP gas savings against a temperature-normalized baseline. The results showed that OPSBC reduced the average indoor unit operating time by 38.8% and the estimated cooling load by 33.9%. Furthermore, the occupant-driven data revealed an average daily vacancy rate of 26.9%, highlighting the strategy’s diagnostic potential. The M&V analysis verified a net GHP gas consumption decrease of 9.7%. While system efficiency was occasionally reduced under partial load conditions, OPSBC’s elimination of unnecessary operation delivered significant energy savings. These findings validate OPSBC as a practical, zero-cost bridging solution for enhancing HVAC energy efficiency in existing commercial buildings.