What is Variable Refrigerant Flow?
Variable refrigerant flow (VRF), also known as variable refrigerant volume (VRV), is an HVAC technology invented by Daikin Industries, Ltd. in 1982. Like ductless minisplits, VRFs use refrigerant as the cooling and heating medium. This refrigerant is conditioned by a single outdoor condensing unit, and is circulated within the building to multiple indoor units.
VRFs are typically installed with an Air conditioner inverter which adds a DC inverter to the compressor in order to support variable motor speed and thus variable refrigerant flow rather than simply perform on/off operation. 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 indoor units to heat or cool as required, while the compressor load benefits from the internal heat recovery. Energy savings of up to 55% are predicted over comparable unitary equipment.  This also results in greater control of the building's interior temperature by the building's occupants.
VRF systems routinely operate at partial loads in the range of 30 to 70% which provides more consistent indoor temperatures and humidity levels as well as provides energy efficiency..
- 1. Very efficient –similar or better than chillers, 180% as efficient as standard splits and RTU’s.
- 2. Small space requirements = more net rentable SF.
- 3. Individual room control – indoor fan coils range from ½-ton up to 8-ton and can heat and cool independently.
- 4.Power distribution – allows building owners to proportion electrical consumption between tenants and bill via automated electronic means.
- 5. Suitable for a broad geographical range. These systems perform to subzero temperatures.
- 6. No gas required; all electric. No auxiliary heat strips needed.
- 7. Modular installation: these systems are great for retrofits, “add-on” tonnage, and phased construction.
- 8. Very low maintenance (particularly compared to central plants).
- 9. Remote control and monitoring via internet.
- 10. Durability – VRF gained a lot of ground in Japan and the Caribbean 25 years ago because they were designed for use where saltwater air corrosion and hurricanes are common..