The optional ‘Electric resistance backup heat for indoor units’ is the only back-up source within the VRF System dialog that is intended to model actual installed equipment. If the actual VRF system will include electric resistance back-up heating within the indoor units, check the box for this and select the meter for reporting the electric power for this end use.
Any actual back-up cooling source, which is not offered as a standard feature of any VRF system that IES is aware of, would need to be modeled as an independent cooling system with its own cooling coil serving the same space as the VRF system. For example, if the space cooling were critical for maintaining computer data center operation, a supplemental or fully redundant back-up cooling source, such as a standard DX cooling system, might be included and controlled to come on only when the VRF system fails to meet the cooling load (e.g., when the zone temperature exceeds an elevated setpoint).
