‘VRF’ stands for ‘variable refrigerant flow’, and ‘VRV’ for ‘variable refrigerant volume’. Both mean
essentially the same thing, but the term VRV is used exclusively by the manufacturer Daikin, who
pioneered the technology and also patented the name.
These systems work on the principle that there is one outdoor unit, serving up to 48 indoor units, and come in either two- or three-pipe forms.
The term heat pump in air conditioning simply means that the system as a whole can either
cool or heat, depending on the demand. A two pipe system works on the principle that all of the indoor
units operate in the same mode, and cooling or heating can be switched by the reversing valve located
in the outdoor unit. Each indoor unit can have its own controller and be fully functional – apart from
individual mode selection (i.e. whether it is cooling or heating).
The term heat recovery in air conditioning means that heat can be absorbed (recovered) from one area of a building and
rejected to another, saving energy.
The system works on the same principle as the two-pipe, except that simultaneous cooling and heating is
available. A branch selector box (or more than one box) acts as a reversing valve, not the outdoor unit,
which means each indoor unit can be individually controlled to provide complete flexibility of use.