VRF — variable refrigerant flow — is the large-building technology that scales the ductless idea up to dozens of zones. VRV (variable refrigerant volume) is Daikin's registered trademark for the same thing; Daikin introduced it in 1982, and the rest of the industry uses the generic 'VRF.' Like a residential multi-zone mini-split, a VRF system runs many individually controlled indoor units from one or more outdoor units on a shared refrigerant loop — but at a scale a home system never reaches, up to 64 indoor units per outdoor unit on Daikin's VRV.
The defining capability is heat recovery: a VRF system can heat some zones while cooling others at the same time, moving rejected heat from a sunny office to a shaded one instead of wasting it. It does this with branch controllers (or a three-pipe layout) that route refrigerant zone by zone. That makes VRF the go-to for hotels, offices, schools, and large mixed-use homes where rooms have very different loads through the day.
For most homeowners shopping a mini-split, VRF is more than they need — a two-to-five-head residential multi-zone covers a house at a fraction of the cost and complexity. The term matters mainly at the boundary: a large custom home, a small commercial space, or a multi-unit building may genuinely call for VRF, and the contractor pool, factory certifications (Mitsubishi City Multi, Daikin VRV, Carrier VRF), and per-ton economics there are different from residential ductless. If a proposal jumps to VRF, ask why a standard multi-zone won't do the job.