Variable Refrigerant Flow (VRF) systems are typically installed with an air conditioner inverter which adds a DC inverter to the compressor to support variable motor speed. By operating at varying speeds, VRF units work only at the needed rate allowing for substantial energy savings at load conditions. Heat recovery VRF technology allows individual units to heat or cool as required, while the compressor load benefits from the internal heat recovery.
The two main system types of VRF's are two pipe and three pipe systems. In two pipe VRF system all of the zones should be in cooling or heating. And in case of three pipe system with heat recovery, it is possible to heat certain zones while cooling others. While the VRF systems have greater initial cost, it allows for better zonal thermal control and overall greater efficiencies.
Cove.tool supports VRF systems that are:
a. air cooled
b. water cooled
Find out about the differences between VRF and VAV systems here.