Energy-saving potential in Indian open-plan offices using Micro-Zonal Occupant Centric Control (MZOCC)

Abstract

HVAC energy consumption can be reduced by air-conditioning only the regions which are occupied. Though occupancy-based smart controllers are common in this regard, they are mostly used for physically separated HVAC zones. Only limited studies have explored localized conditioning within HVAC zones. Micro-zonal occupant-centric control (MZOCC) aims at maintaining a target air temperature only in the virtual micro-zones where occupants are present, leaving other regions unconditioned. There is a need to understand the potential of MZOCC in terms of investment and energy savings and develop strategies for improving it. This study addresses these research gaps by exploring MZOCC in a typical Indian open-plan office using an experimentally validated CFD model. Cooling pattern, energy consumption and thermal contours for varying (1) diffuser arrangement, (2) airflow control, and (3) occupancy conditions are explored.The study’s key findings are (1) MZOCC induces substantial energy savings at minimal additional investment; (2) Strategizing diffuser location and airflow control are required to avoid merging of air jets and heavy thermal gradients; (3) Using a low-velocity flow (setback-flow) or maintaining a higher setpoint temperature (setback-temperature) in unoccupied micro-zones improves the efficiency of MZOCC. This study extends the literature on MZOCC by addressing operational challenges in MZOCC.