This paper provides a new implementation model of the BACnet objects on high-level functionality for variable refrigerant flow (VRF) air-conditioning systems for commercial buildings. First, the paper discusses a model of the air-conditioner cell that consists of a group of BACnet standard type objects using the Unified Modeling Language (UML). In addition, this paper provides a new concept of a virtual wattmeter using the BACnet Accumulator object type for power consumption allocation to each tenant of the building. Examples of computer simulation and field testing show the effectiveness of our approach to expedite communication access and to provide more accurate allocation of power consumption for VRF air-conditioning systems.

Units: SI