2 Pipe VRV/VRF Air to Air
Invented by Daikin in 1982, variable refrigerant volume technology allows up to 64 indoor units to share pipework to the outdoor unit. VRV is a Daikin trademark so other manufacturers use VRF (variable refrigerant flow).
The main difference to the split air to air is that the expansion valve is in the indoor unit (to control refrigerant flow) and indoor units share refrigerant pipes from the outdoor unit.
Aimed at the commercial market but can been applied to residential properties, especially larger houses and high end installations.
Pros
High capacity systems
High efficiency
2+ outdoor units can be connected for redundancy
Allows long pipe distances so units can be placed down the garden
Cons
Expensive and no grant
Indoor units must all be in either heating or cooling
Difficult to retrofit
Requires F-Gas
3 Pipe VRV/VRF Air to Air
The 3 pipe VRV/VRF is a development on the 2 pipe. The 3rd pipe adds ‘heat recovery’ which means that some of the indoor units can be heating and other can be cooling simultaneously. This can be incredibly energy efficient because if you’re cooling rooms in the summer, that heat taken from those rooms can be put into the hot water for showers, or into a heated pool.
This system requires a ‘branch box’ which connects the 2 pipe indoor units to the 3 pipe outdoor units. The changeover between heated and cooled zones happens in the branch box.
Pros
Flagship heat pump system
Ideal for new/referb high end properties
Best comfort levels
Ultimate flexibility
Cons
No Government funding
Requires F-Gas
Complicated system
